U.S. patent application number 11/805833 was filed with the patent office on 2007-12-27 for fastener installation system.
Invention is credited to David James Fulbright.
Application Number | 20070295779 11/805833 |
Document ID | / |
Family ID | 38801984 |
Filed Date | 2007-12-27 |
United States Patent
Application |
20070295779 |
Kind Code |
A1 |
Fulbright; David James |
December 27, 2007 |
Fastener installation system
Abstract
A blind fastener installation tool which accomplishes the blind
installation of a series of fasteners is described in detail in
this specification. The blind fastener installation tool comprises
a structural housing which features a means for securing a fastener
installation assembly in position relative to said structural
housing during the blind installation of a fastener; and a means
for reciprocating said fastener installation assembly relative to
said structural housing at the conclusion of a cyclic blowline-fed
or clip-fed blind installation of a fastener. The blind fastener
installation tool also comprises a fastener installation assembly
comprising (1) a pull rod assembly comprising means for pulling a
first portion of a fastener; (2) an annular, piston-actuated,
direct action, piston-decoupled pull rod actuation assembly to
translate the pull rod assembly relative to said fastener
installation assembly when said fastener installation assembly is
secured at a fastener installation assembly fastener installation
position, thereby pulling said first portion of said fastener until
blind installation of said fastener is complete; and (3) a nose
assembly comprising (3a) a fastener receptacle for securing the
position of a fastener relative to said nose assembly during blind
installation of said fastener; and (3b) one or more optional pull
rod translation dampening assemblies to smoothly and effectually
dampen the sudden translation of said pull rod assembly after
pintail break during blind installation of a pintail-break-type
fastener. The blind fastener installation tool also comprises an
optional fastener delivery assembly, said optional fastener
delivery assembly constituting: (1) a clip-fed fastener delivery
system; or (2) a blowline-fed fastener delivery system.
Inventors: |
Fulbright; David James;
(Waco, TX) |
Correspondence
Address: |
LAW OFFICE OF PAUL W. FULBRIGHT, PLLC
2003 J.J. PEARCE DRIVE
RICHARSON
TX
75081-5447
US
|
Family ID: |
38801984 |
Appl. No.: |
11/805833 |
Filed: |
May 24, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11445483 |
Jun 1, 2006 |
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11805833 |
May 24, 2007 |
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11035009 |
Jan 13, 2005 |
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11445483 |
Jun 1, 2006 |
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Current U.S.
Class: |
227/138 |
Current CPC
Class: |
B21J 15/105 20130101;
B21J 15/285 20130101; B21J 15/28 20130101; B21J 15/043 20130101;
B21J 15/32 20130101; B21J 15/22 20130101 |
Class at
Publication: |
227/138 |
International
Class: |
B21J 15/12 20060101
B21J015/12 |
Claims
1. A blind fastener installation tool to effectuate the blind
installation of a series of fasteners, said blind fastener
installation tool comprising: (a) a structural housing comprising:
(1) means for securing a fastener installation assembly in position
relative to said structural housing during the blind installation
of a fastener; (2) means for reciprocating said fastener
installation assembly relative to said structural housing at the
conclusion of blind installation of a fastener; and (b) a fastener
installation assembly, said fastener installation assembly
comprising: (1) a pull rod assembly comprising a pull rod actuation
member and means for pulling a first portion of a fastener; (2) an
annular, piston-actuated, piston-decoupled pull rod actuation
assembly, said annular, piston-actuated, piston-decoupled pull rod
actuation assembly featuring the direct action of a drive piston
against said pull rod actuation member, said annular,
piston-actuated, piston-decoupled pull rod actuation assembly
translating the pull rod assembly relative to said fastener
installation assembly when said fastener installation assembly is
secured at a fastener installation assembly fastener installation
position, thereby pulling said first portion of said fastener until
blind installation of said fastener is complete; (3) a nose
assembly comprising a fastener receptacle for securing the position
of a fastener relative to said nose assembly during blind
installation of said fastener.
2. The blind fastener installation tool of claim 1 wherein said
nose assembly further comprises one or more pull rod translation
dampening assemblies to smoothly and effectually dampen sudden
translation of said pull rod assembly after blind installation of a
fastener.
3. The blind fastener installation tool of claim 2 wherein at least
one of said one or more pull rod translation dampening assemblies
dampens the sudden translation of said pull rod assembly after
pintail break during blind installation of a pintail-break-type
fastener.
4. The blind fastener installation tool of claim 3 wherein said
structural housing further comprises a means for inter-connecting
with a fastener delivery assembly; and wherein said blind fastener
installation tool further comprises said fastener delivery
assembly, said fastener delivery assembly comprising a clip-fed
fastener delivery system, said clip-fed fastener delivery system
comprising means for securing the sequential oriented placement of
each fastener of said series of fasteners (said series of fasteners
housed within a portable housing) within one or more fastener
presenters, said one or more fastener presenters securely
presenting each fastener in succession to said fastener receptacle
as the fastener installation assembly is reciprocated and prior to
said fastener installation assembly arriving at said fastener
installation assembly fastener installation position.
5. The blind fastener installation tool of claim 3 wherein said
structural housing further comprises a means for inter-connecting
with a fastener delivery assembly; and wherein said blind fastener
installation tool further comprises said fastener delivery
assembly, said fastener delivery assembly comprising a blowline-fed
fastener delivery system, said blowline-fed fastener delivery
system comprising: means for securing the sequential oriented
placement of each fastener of said series of fasteners (said series
of fasteners housed within a bulk supply receptacle) into a
blowline, said blowline transporting each said fastener in
succession to a catcher and thereafter to one or more fastener
presenters, said one or more fastener presenters securely
presenting each fastener in succession to said fastener receptacle
as the fastener installation assembly is reciprocated and prior to
said fastener installation assembly arriving at said fastener
installation assembly fastener installation position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of, and claims
the benefit of, and incorporates by reference the entirety of, the
following applications: [0002] U.S. Provisional Application No.
60/536,593, filed Jan. 15, 2004 (entitled "A Fastener Installation
System"). [0003] U.S. Provisional Application No. 60/604,648, filed
Aug. 26, 2004 (entitled "Improvements to a Fastener Installation
System"). [0004] U.S. Nonprovisional application Ser. No.
11/035,009, filed Jan. 13, 2005 (entitled "A Fastener Installation
System"). [0005] U.S. Nonprovisional application Ser. No.
11/445,483, filed Jun. 1, 2006 (entitled "A Fastener Installation
System").
BACKGROUND OF THE INVENTION
[0006] Blind rivet installation tools have been in existence for
many years. However, the vast majority of prior art designs have
suffered from one or more important disadvantages.
[0007] First, the vast majority of prior art designs impart recoil
to the operator upon rivet installation. Second, the vast majority
of prior arts designs are manually loaded, which is extremely
inefficient in an industrial environment. Third, most prior art
blind rivet installation tools are insufficiently reliable for
industrial applications. Fourth, few, if any, prior art designs
were designed to operate in multiple environments. Fifth, most
prior art designs are noisy, contributing to a hostile work
environment.
[0008] It is to the correction of these deficiencies, among others,
that the instant disclosure is directed.
BRIEF SUMMARY OF THE INVENTION
[0009] A blind fastener installation tool which effectuates the
blind installation of a series of fasteners is described in detail
in this specification.
[0010] The blind fastener installation tool comprises a structural
housing which itself comprises (1) means for inter-connecting with
a fastener delivery assembly; (2) means for securing a fastener
installation assembly in position relative to said structural
housing during the blind installation of a fastener; and (3) means
for reciprocating said fastener installation assembly relative to
said structural housing at the conclusion of a cyclic blowline-fed
or clip-fed blind installation of a fastener.
[0011] The blind fastener installation tool also comprises a
fastener installation assembly, said fastener installation assembly
comprising (1) a pull rod assembly comprising means for pulling a
first portion of a fastener; (2) an annular, piston-actuated,
direct action, piston-decoupled pull rod actuation assembly to
translate the pull rod assembly relative to said fastener
installation assembly when said fastener installation assembly is
secured at a fastener installation assembly fastener installation
position, thereby pulling said first portion of said fastener until
blind installation of said fastener is complete; and (3) a nose
assembly comprising (3a) a fastener receptacle for securing the
position of a fastener relative to said nose assembly during blind
installation of said fastener; and (3b) one or more optional pull
rod translation dampening assemblies to smoothly and effectually
dampen the sudden translation of said pull rod assembly after
pintail break during blind installation of a pintail-break-type
fastener;
[0012] The blind fastener installation tool also comprises an
optional fastener delivery assembly, said optional fastener
delivery assembly constituting: (1) a clip-fed fastener delivery
system, said clip-fed fastener delivery system comprising means for
securing the sequential oriented placement of each fastener of said
series of fasteners (said series of fasteners housed within a
portable housing) within one or more fastener presenters, said one
or more fastener presenters securely presenting each fastener in
succession to said fastener receptacle as the fastener installation
assembly is reciprocated and prior to said fastener installation
assembly arriving at said fastener installation assembly fastener
installation position; or (2) a blowline-fed fastener delivery
system, said blowline-fed fastener delivery system comprising:
means for securing the sequential oriented placement of each
fastener of said series of fasteners (said series of fasteners
housed within a bulk supply receptacle) into a blowline, said
blowline transporting each said fastener in succession to one or
more fastener presenters, said one or more fastener presenters
securely presenting each fastener in succession to said fastener
receptacle as the fastener installation assembly is reciprocated
and prior to said fastener installation assembly arriving at said
fastener installation assembly fastener installation position.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0013] FIG. 1 is a side view of the invention at stage one of the
fastener installation process described herein.
[0014] FIG. 1A is an enlarged cross-sectional view of the nose
assembly of the invention at stage one of the fastener installation
process described herein.
[0015] FIG. 1B is an isometric view of the collet lock actuating
assembly of the invention.
[0016] FIG. 1C is an enlarged cross-sectional view which depicts
the outer collet in a locked position.
[0017] FIG. 1D is an enlarged cross-sectional view which depicts
the outer collet in an unlocked position.
[0018] FIG. 1E is an exploded isometric view of the collet lock
actuating assembly.
[0019] FIG. 1F is an isometric view of a portion of the clip-fed
rivet delivery system.
[0020] FIG. 2 is a side cross-sectional view of the invention at
stage two of the fastener installation process described
herein.
[0021] FIG. 2A is an enlarged side cross-sectional view of a
rearward portion of the invention at stage two of the fastener
installation process described herein.
[0022] FIG. 3 is a side cross-sectional view of the invention at
stage three of the fastener installation process described
herein.
[0023] FIG. 3A is an enlarged side cross-sectional view of a
rearward portion of the invention at stage three of the fastener
installation process described herein.
[0024] FIG. 3B is an enlarged side cross-sectional view of a
forward portion of the invention at stage three of the fastener
installation process described herein.
[0025] FIG. 4 is a side cross-sectional view of the invention at
stage four of the fastener installation process described
herein.
[0026] FIG. 5 is a side cross-sectional view of the invention at
stage five of the fastener installation process described
herein.
[0027] FIG. 5A is an enlarged side cross-sectional view of a
rearward portion of the invention at stage five of the fastener
installation process described herein.
[0028] FIG. 5B is an enlarged side cross-sectional view of a
forward portion of the invention at stage five of the fastener
installation process described herein.
[0029] FIG. 6 is a side cross-sectional view of the invention at
stage six of the fastener installation process described
herein.
[0030] FIG. 6A is an enlarged side cross-sectional view of a
rearward portion of the invention at stage six of the fastener
installation process described herein.
[0031] FIG. 7 is a side cross-sectional view of the invention at
stage seven of the fastener installation process described
herein.
[0032] FIG. 8 is a side cross-sectional view of the invention at
stage eight of the fastener installation process described
herein.
[0033] FIG. 8A is an isometric view of a portion of the invention
at stage eight of the fastener installation process described
herein.
[0034] FIG. 8B is an isometric portion of the clip-fed rivet
delivery system.
[0035] FIG. 8C is an isometric view of a paw, paw stop assembly,
and paw stop actuator.
[0036] FIG. 8D is a side cross-sectional view of a paw stop
assembly.
[0037] FIG. 9 is a side view of a portion of the invention at stage
nine of the fastener installation process described herein.
[0038] FIG. 9A is an isometric view of a portion of the invention
at stage nine of the fastener installation process described
herein.
[0039] FIG. 10 is a side cross-sectional view of a portion of the
invention at stage ten of the fastener installation process
described herein.
[0040] FIG. 10A is an isometric view of a portion of the invention
at stage ten of the fastener installation process described
herein.
[0041] FIG. 10B is an isometric view of a portion of the invention
at stage ten of the fastener installation process described
herein.
[0042] FIG. 11 is a side cross-sectional view of the invention at
stage eleven of the fastener installation process described
herein.
[0043] FIG. 12 is an isometric view of a portion of the invention
at stage twelve of the fastener installation process described
herein.
[0044] FIG. 12A is an isometric view of a portion of the invention
at stage twelve of the fastener installation process described
herein.
[0045] FIG. 12B is an isometric view of a portion of the invention
at stage twelve of the fastener installation process described
herein.
[0046] FIG. 13 is an isometric view of a portion of the invention
at stage thirteen of the fastener installation process described
herein.
[0047] FIG. 14 is omitted.
[0048] FIG. 15 is an isometric view of the inner collet in its open
position.
[0049] FIG. 16 is an isometric view of the inner collet in its
closed position.
DETAILED DESCRIPTION OF THE INVENTION
[0050] This application is a continuation-in-part of, and claims
the benefit of, and incorporates by reference the entirety of,
three (3) prior patent applications.
[0051] This application incorporates the entirety of U.S.
Provisional Application No. 60/536,593, filed Jan. 15, 2004
(entitled "A Fastener Installation System"), by reference, and,
herein, whenever referenced, said provisional patent application
will commonly be referred to as the "fastener installation system
provisional patent application."
[0052] This application also incorporates the entirety of U.S.
Provisional Application No. 60/604,648, filed Aug. 26, 2004
(entitled "Improvements to a Fastener Installation System"), by
reference, and, herein, whenever referenced, said provisional
patent application will commonly be referred to as the "fastener
installation system improvements provisional patent
application."
[0053] This application also incorporates the entirety of U.S.
Nonprovisional application Ser. No. 11/035,009, filed Jan. 13, 2005
(entitled "A Fastener Installation System"), by reference, and,
herein, whenever referenced, said nonprovisional patent application
will commonly be referred to as the "'009 fastener installation
system nonprovisional patent application."
[0054] This application also incorporates the entirety of U.S.
Nonprovisional application Ser. No. 11/445,483, filed Jun. 1, 2006
(entitled "A Fastener Installation System"), by reference, and,
herein, whenever referenced, said nonprovisional patent application
will commonly be referred to as the "'483 fastener installation
system nonprovisional patent application."
[0055] With reference now to the drawings, and in particular with
reference to FIG. 1, a fastener installation system 1 for the
installation of fasteners 3 is shown.
[0056] The specific fastener installation system 1 shown is a blind
rivet installation system 1 for the blind installation of rivets 3,
and the specific blind rivet installation system 1 shown features a
blind rivet installation tool 5 equipped with a clip-fed rivet
delivery system 7.
[0057] With reference now to the drawings, and in particular with
reference to FIG. 1, a blind rivet installation system 1 for the
installation of rivets 3 is shown. The blind rivet installation
system 1 features a blind rivet installation tool 5 equipped with a
clip-fed rivet delivery system 7 as shown.
[0058] The rivets 3 (such as rivet 3a) for which this tool is
particularly well suited are what are commonly known in the
industrial and aerospace fastening industries as blind rivets,
although the tool will obviously perform its intended function with
any rivet, fastener or workpiece similarly designed.
[0059] Overview of Stages of Blind Fastener Installation.
[0060] The blind rivet installation tool 5 effectuates the blind
installation of rivets 3 through a cyclic series of thirteen stages
described hereinbelow. The thirteen stages of blind installation
are: [0061] Stage One: Rivet ready. [0062] Stage Two: Inner Collet
Closure. [0063] Stage Three: Rivet Installation Complete Except for
Pin Break. [0064] Stage Four: Rivet Installation Post Pin Break.
[0065] Stage Five: Inner Collet Re-Opening. [0066] Stage Six:
Piston Return Complete. [0067] Stage Seven: Outer Collet Opens.
[0068] Stage Eight: Reciprocation: Nose assembly retracted; rivet
captured at paw stop. [0069] Stage Nine: Reciprocation: rivet
presentation. [0070] Stage Ten: Rivet load. [0071] Stage Eleven:
Nose assembly full extension. [0072] Stage Twelve: Stroke presenter
down. [0073] Stage Thirteen: Presenter prior to rivet capture.
[0074] The status/state of the blind rivet installation tool 5
subsystems and components, and the rivets 3 being manipulated by
the blind rivet installation tool 5 as well as by the clip-fed
rivet delivery system 7, at each stage of the process, are
discussed in detail in this specification.
[0075] Automated/Computerized Execution of the Stages of Blind
Rivet Installation.
[0076] As described in great detail hereinbelow, the blind rivet
installation tool 5 effectuates the blind installation of rivets 3
through a cyclic series of thirteen stages. Execution of the
thirteen stages is efficiently effectuated by means of automation,
namely, through the use of programmable controllers,
micro-controllers, and/or electro-mechanical sensors the uses and
applications of which are well-known to persons of ordinary skill
in the art of electromechanical automation.
[0077] The key goal of automating the thirteen-stage installation
process is simply this: (a) reduce the cycle time as much as
possible by, for example, executing stage steps in parallel
whenever possible; and (b) ensure that the execution of no stage
proceeds until any electromechanical sensors employed impart
confidence that the pre-requisites of that stage's execution are in
place. The first objective imparts operational speed; the second
imparts operational safety and security.
[0078] The person of ordinary skill in the art of automation will
require no extensive recitation of the automation implementation
issues presented by the blind rivet installation process described
herein. However, some useful lessons have been, and continue to be,
learned by the inventor, and they are discussed where applicable in
the discussion of each of the thirteen stages below.
[0079] Useful Conventions Regarding Relative Position.
[0080] In describing the position of each of the invention's
components, as well as the rivet workpieces being acted upon,
certain default conventions are useful.
[0081] Viewing the invention as shown in FIG. 1, one can utilize
three perpendicular axes, denominated the x-, y- and z-axes,
defining an orthogonal coordinate system, to describe relative
position. As shown in FIG. 1, the x-axis describes position along a
horizontal axis, with movement to the "left" (also described as
"forward" movement), as shown in FIG. 1, being associated with
increasing x position. Conversely, movement to the "right" (also
described as "backward" or "rearward" movement), as shown in FIG.
1, is associated with decreasing x position.
[0082] As also shown in FIG. 1, the y-axis describes position along
a vertical axis, with movement "upwards", or "elevating" movement,
as shown in FIG. 1, being associated with increasing y position.
Conversely, movement "downwards", or "lowering" movement, as shown
in FIG. 1, is associated with decreasing y position.
[0083] As also shown in FIG. 1, the z-axis describes position along
an axis perpendicular to both the x-axis and the y-axis, with
shifting movement "to the right" (from the vantage point of a
viewer facing in the positive x direction), or "into the page" as
shown in FIG. 1, being associated with increasing z position.
Conversely, movement "to the left", or out of the page towards the
reader as shown in FIG. 1, is associated with decreasing z
position.
[0084] Viewing the invention as shown in FIG. 1, one can also
utilize a cylindrical coordinate system, denominated x-r-a.degree.,
to describe relative position.
[0085] In such a cylindrical coordinate system, as shown in FIG. 1,
and as in the case of the orthogonal x-y-z coordinate system
described above, the x-axis describes position along a horizontal
axis, with movement to the "left" (also described as "forward"
movement), as shown in FIG. 1, being associated with increasing x
position. Conversely, movement to the "right" (also described as
"backward" or "rearward" movement), as shown in FIG. 1, is
associated with decreasing x position.
[0086] As also shown in FIG. 1, the r-axis describes position along
a radial axis fixed or centered at the x-axis, with radial movement
"outwards", as shown in FIG. 1, being associated with increasing r
position. Conversely, radial movement "inwards", as shown in FIG.
1, is associated with decreasing r position.
[0087] As also shown in FIG. 1, the a.degree.-axis describes
angular position, relative to an angular origin located straight
overhead (i.e., at "top dead center") when the blind rivet
installation tool 5 is held as shown in FIG. 1, with rotational
movement "clockwise" (from the vantage point of a viewer facing in
the positive x direction), or top portion--away and bottom
portion--towards the reader, as shown in FIG. 1, being associated
with increasing a.degree. position. Conversely, rotational movement
"counterclockwise", or top portion--towards and bottom
portion--away from the reader, as shown in FIG. 1, is associated
with decreasing a.degree. position.
[0088] It will of course be understood that these conventions
should be ignored when the discussion of a particular figure makes
it reasonably apparent to a person of ordinary skill in the art
that a particular, and different, convention has been adopted to
make or clarify a specific point.
[0089] Stage One: Rivet Ready.
[0090] Returning, now, to FIG. 1, the blind rivet installation tool
5 comprises a nose 9, said nose 9 featuring a nose insert 11, a
collet lock 13, a front end cap 15, a hydraulic cylinder 17, a
bridge 19, a reciprocation air cylinder 21, a left cylinder housing
23, a left handle 25, a gear drive housing 27, a trigger 29, a
presentation air cylinder 33, a turnbuckle 35, a presentation
connecting rod 37, a large presentation sprocket 39, and a collet
lock bracket 41. The relationship of these elements, and their
interoperability, are described more fully below.
[0091] As shown, and as more fully described in the figures which
follow, the clip-fed rivet delivery system 7 is connected to the
blind rivet installation tool 5 so as to facilitate the delivery of
rivets 3 to the blind rivet installation tool 5 for blind
installation.
[0092] At stage one, the following important status items should be
noted (note: not all of the components or assemblies enumerated in
this paragraph listing are itemized in FIG. 1; however, they are
defined and described fully in the corresponding figures that
follow): [0093] (a) the nose assembly 43 (comprising nose 9) is
fully extended with a rivet 3a ready for installation; [0094] (b)
the outer collet 45 is locked; [0095] (b1) the collet lock bracket
41 has pivoted to a rearward location, moving the collet lock 13
back; [0096] (b2) the collet lock air cylinder 61 is retracted;
[0097] (c) the jaws 49 are in the "accept" position; and [0098] (d)
the next rivet in succession (not shown in FIG. 1), rivet 3b, is
against the paws (i.e., rivet 3b fully captured as described more
fully below).
[0099] Thus, as shown in FIG. 1, the nose assembly 43 (see FIG. 1A)
is fully extended, thus extending a rivet 3a forward for blind
installation. Blind installation occurs when the rivet 3a is placed
in a rivet hole, and the trigger 29 of the blind rivet installation
tool 5 is depressed, installing the rivet even though the user has
immediate physical access only to one side of the rivet 3a during
installation. Through a process more fully described below, the
rivet 3a is automatically installed.
[0100] A comparison of FIG. 1 and FIG. 1C (showing outer collet 45
and collet lock 13 in the locked position) with FIG. 1D (showing
outer collet 45 and collet lock 13 in the unlocked position)
reveals the telltale gap between the collet lock 13 and front end
cap 15. In FIG. 1 and FIG. 1C the gap is small (outer collet 45 and
collet lock 13 locked); in FIG. 1D, the gap is comparatively larger
(outer collet 45 and collet lock 13 unlocked).
[0101] Returning, now, to FIG. 1, presentation air cylinder 33,
turnbuckle 35, and presentation connecting rod 37 are visible
through access portal 31 and are shown in a substantially
retracted/rearward position. Also visible is large presentation
sprocket 39 which is connected to presentation connecting rod 37
via dowel pin 71. Large presentation sprocket 39 rotates back
(i.e., clockwise from the vantage point of FIG. 1) and forth
(counterclockwise) between two endpoint loci during operation of
the blind rivet installation tool 5; at stage one, the position of
large presentation sprocket 39 is best described as being nearly
fully clockwise rotated.
[0102] Turning, now, to FIG. 1 A, a close-up cross-sectional view
of nose assembly 43 is depicted. Inspection of this figure reveals
an important subassembly, the pull rod assembly 73, which comprises
jaw collet 47, jaws 49, jaw spring follower 51, jaw spring 53, pull
rod 55, forward pull rod outer seal 57, dampening spring 59, pull
rod coupling 101 (not shown in FIG. 1A), and pull rod sealing tube
103 (not shown in FIG. 1A).
[0103] During operation of the blind rivet installation tool 5,
pull rod assembly 73 translates back and forth within nose assembly
43. At this stage one, it is shown in its forwardmost position.
[0104] In pull rod assembly 73, jaws 49 are positioned within jaw
collet 47. The jaws 49 (through the action of adjacent jaw spring
follower 51) are urged forward against jaw collet 47 by jaw spring
53 which abuts a stop within pull rod 55. When jaws 49 are urged
forward against jaw collet 47, the outer frusto-conical surface of
the jaws 49 and the inner frusto-conical surface of jaw collet 47
results in the jaws 49 being urged into a closed (i.e., radially
inward) and forward position.
[0105] At stage one, as shown in FIG. 1A, the pull rod assembly 73
is in its forwardmost position. At that position, the forward face
of jaws 49 impinges upon the rearmost face of nose insert 11; this
action results in jaws 49 opening (i.e., extending radially
outward), and translating backward with respect to jaw collet 47,
the radially outward expansion opening the jaws 49 sufficiently (to
the "rivet acceptance position") to receive the pintail of a rivet
3.
[0106] Turning, now, to FIG. 1B, FIG. 1C, FIG. 1D, and FIG. 1E, a
series of figures is provided that reveals the operation of the
collet lock actuating assembly 75.
[0107] FIG. 1B, an isometric drawing, depicts the collet lock
actuating assembly 75 which comprises collet lock 13, collet lock
bracket 41, clevis 63, clevis pin 65, collet lock air cylinder 61,
pivot pin 67, right handle 69, and left handle 25 (not shown in
FIG. 1B).
[0108] As shown in FIG. 1B, when air cylinder 61 is retracted,
collet lock bracket 41 rotates clockwise (as viewed from the
vantage point of FIG. 1B along the z-axis) about pivot pin 67 which
is restrained by left handle 25 and right handle 69. When collet
lock bracket 41 is so rotated, the collet lock bracket tongs 77,
fitted so as to engage collet lock recesses 79, urge the collet
lock 13 in a rearward direction relative to the nose assembly 43
and the front end cap 15.
[0109] The details of FIG. 1B are clarified by reference to FIG. 1E
which provides an exploded view of the collet lock actuating
assembly 75. FIG. 1E reveals the shape of outer collet 45 and,
importantly, the presence of the nose locking groove 81. It also
shows the pivot pin recess 85 which receives pivot pin 67 so as to
rotatably secure collet lock bracket 41.
[0110] FIG. 1C provides a close-up cross-sectional view of the
outer collet 45, the collet lock 13, and portions of the nose
assembly 43 and front end cap 15. Importantly, in FIG. 1C, the
outer collet 45 is shown in the locked position, its position at
stage one.
[0111] Note that the outer collet locking tooth 83 is fully seated
within the nose locking groove 81, thus locking outer collet 45 in
place and preventing forward or backward movement of nose 9
relative to front end cap 15. Note, as well, the presence of a very
small gap between the forward face of outer collet locking tooth 83
and the forward face of nose locking groove 81. A similar gap, or
tolerance, exists between the rearward face of outer collet locking
tooth 83 and the rearward face of nose locking groove 81.
[0112] These gaps exist to ensure effective mating of outer collet
locking tooth 83 and nose locking groove 81. However, it is
desirable to substantially minimize these gaps in order to ensure
that, for example, during stage two, when pull rod 55 is urged in a
rearward direction relative to nose 9 and front end cap 15, at a
time when it is desired to restrain rearward motion of the nose 9,
nose 9 moves as little as practicable prior to the outer collet
locking tooth 83 engaging the nose locking groove 81 so as to
conserve installation stroke length.
[0113] Outer collet 45 features two frusto-conical surfaces on each
of its respective tongs; reference to FIG. 1C reveals
frusto-conical surface 45a1 and frusto-conical surface 45e2. These
frusto-conical surfaces are designed to interact with corresponding
frusto-conical surfaces on the collet lock (see surface 13(1)) and
the front end cap (see surface 15(2)), so as to close the outer
collet 45, as shown in FIG. 1C, or open the outer collet 45, as
shown in FIG. 1D.
[0114] FIG. 1E depicts the three-dimensional shape of outer collet
45, while FIG. 1C and FIG. 1D depict its cross-sectional
appearance. Notice, with reference to FIG. 1E, that the outer
collet 45 features a plurality of angularly spaced outer collet
tongs; in the preferred embodiment shown herein, the outer collet
tongs are designated 45a, 45b, 45c, 45d, 45e, 45f, 45g, and 45h.
Outer collet 45 acts as a spring, and it is produced in such a
manner that, when it is at its at-rest, or "open" position, as
shown in FIG. 1D, the outer collet tongs 45a, 45b, 45c, 45d, 45e,
45f, 45g, and 45h "spring open" so as to expand radially and to
separate themselves from one another, and from the nose axis 89, to
a greater extent than would be the case if the spring were in its
radially compressed, or "closed" position, as shown in FIG. 1C.
Note the contrast in the position of outer collet tong 45a as shown
in FIG. 1C and FIG. 1D; in FIG. 1D, outer collet tong 45a is
"sprung open" to such an extent that the innermost surface of outer
collet locking tooth 83 is radially outside of the outer surface of
nose 9, while, in FIG. 1C, outer collet tong 45a has been radially
compressed, or "closed", to such an extent that the innermost
surface of outer collet locking tooth 83 is fully seated within
nose locking groove 81 as described above.
[0115] The methods and means by which such an outer collet 45,
featuring a spring constant, is produced are well-known to those of
ordinary skill in the art of collet manufacture. One method of
manufacture would involve the heat treatment of a collet, said
collet sprung open prior to heat treat by a pre-determined amount,
so that the collet naturally features the desired quality of
springing open in an outward radial direction after a radially
inwardly compressive force is removed.
[0116] A comparative study of FIG. 1D and FIG. 1C reveals the
manner by which collet lock 13 and front end cap 15 cooperate so as
to move outer collet 45 from an unlocked position to a locked
position. In FIG. 1D, the outer collet 45 is, as described above,
shown in an unlocked, or "open", position. Notice the forwardly
displaced position of collet lock 13. Notice, as well, that, when
outer collet tong 45a springs radially outward, its natural
spring-based tendency, smooth frusto-conical surfaces 45a(2)
through 45h(2) impinge upon frusto-conical surface 15(2) and, due
to the outer collet 45 spring constant, outer collet 45 expands
radially outward and translates forward as shown (the translation
generating a small longitudinal gap between the rearmost surface of
outer collet 45 and the forwardmost face of front end cap outer
collet seat 87). In this unlocked position, nose 9 can slide, in a
longitudinal direction, smoothly and easily past outer collet 45
without interference.
[0117] When it is desired to move outer collet 45 from the unlocked
position shown in FIG. 1D to the locked position shown in FIG. 1C,
the collet lock 13 is translated backwards (owing to the action of,
among other things, collet lock bracket 41, as described above).
The backwards movement of collet lock 13 results in surface 13(1)
impinging upon surfaces 45a(1) through 45h(1), with the result
being that outer collet 45 is translated backwards and radially
compressed, so that, as shown in FIG. 1C, when outer collet 45 is
indeed locked, frusto-conical surface 13(1) has fully engaged and
matched frusto-conical surfaces 45a(1) through 45h(1),
frusto-conical surface 15(2) has fully engaged frusto-conical
surfaces 45a(2) through 45h(2), and outer collet locking tooth 83
is fully seated within nose locking groove 81.
[0118] At this juncture, several aspects of the design of outer
collet 45 can now be appreciated.
[0119] The longitudinal length of outer collet 45 minimizes the
force necessary to radially compress the cantilever outer collet
tongs, such as outer collet tong 45a, and thus close the collet.
This minimizes the work to be done by the collet lock actuating
assembly 75 in closing the outer collet 45. Furthermore, the length
also minimizes the bending stresses at work within the outer collet
45 as it moves back and forth from its locked and unlocked
positions.
[0120] As described above, collet lock 13, outer collet 45, front
end cap 15, outer collet locking tooth 83, and nose locking groove
81 have all been designed so that their respective mating surfaces,
including their respective cylindrical and frusto-conical surfaces,
as described above, meet and effectually match. In addition, outer
collet 45, as described above, has been designed so that, when it
is fully radially compressed to its closed and locked position, the
innermost diameter of outer collet locking tooth 83 effectually
matches the outside diameter of the nose locking groove 81; in
addition, when outer collet 45 is fully radially compressed to its
closed and locked position, the inner diameter of the outer collet
tongs proximate to (but outside) the outer collet locking teeth
effectually matches the outside diameter of the nose 9. These
geometric fits, coupled with the longitudinal length of the collet
lock 13, accomplish several valuable design objectives.
[0121] The collet lock 13, with its longitudinal length and
frusto-conical surface 13(1), cooperates with front end cap 15,
with its longitudinal length and frusto-conical surface 15(2), to
insure that outer collet 45 is always in precise longitudinal and
radial alignment so that outer collet locking tooth 83 easily drops
into nose locking groove 81 with only a modicum of force. It is
helpful to note that outer collet locking tooth 83 is not clamped
into nose locking groove 81; rather, it is fitted into place, and
this fitting occurs primarily as a result of a modicum of inwardly
radially compressive force being applied to the outer collet tongs
so as to bring the inner surface of the outer collet tongs adjacent
to (but outside) the outer collet locking teeth into union with the
outer surface of the nose 9. In short, when the outer collet 45 is
closed, a fairly precise slip fit occurs.
[0122] The design rationale for the slip fit lies in an
appreciation for the fact that outer collet 45 effectuates its
intended purpose when, during stage two, the outer collet locking
tooth 83 engages nose locking groove 81 so as to restrain the
rearward motion of the nose 9 when pull rod 55 is urged in a
rearward direction relative to nose 9. As can be seen from an
inspection of FIG. 1C, when pull rod 55 is urged rearward, the
forwardmost face of outer collet locking tooth 83 fully engages the
forwardmost face of nose locking groove 81. During stage two, the
sheer forces developed at this juncture are substantial, and a
design objective of the collet lock actuating assembly 75 is to
ensure that the outer collet locking tooth 83 is fully seated
within the nose locking groove 81 (with the forwardmost face of
outer collet locking tooth 83 meeting the forwardmost face of nose
locking groove 81 across their entire respective surface areas), so
that the outer collet locking tooth 83, which features a
substantial longitudinal x-axis dimension, can withstand the
substantial sheer forces imparted by the forwardmost face of nose
locking groove 81.
[0123] The sheering force imparted upon outer collet locking tooth
83 is transferred by the action of the rearmost surface of outer
collet 45 upon the forwardmost face of front end cap outer collet
seat 87 which it meets (note: when outer collet 45 is open, as
shown in FIG. 1D, there is a small gap between the rearmost surface
of outer collet 45 upon the forwardmost face of front end cap outer
collet seat 87). Front end cap 15 is secured in position relative
to the blind rivet installation tool 5 by means of a threaded
connection to hydraulic cylinder 17 as more fully described
below.
[0124] Outer collet 45 is preferably made of a high-strength,
fatigue-resistant, alloy steel.
[0125] Nose 9 can be constructed of numerous alloys, provided that
the front surface of the nose locking groove 81 is capable of
withstanding the bearing stresses generated at stage two when it
meets outer collet locking tooth 83. Thus, the nose could be
functionally and effectually constructed of any alloy which meets
this technical requirement or, alternatively, for example, it might
also be manufactured of a lower-strength alloy which has been
surface treated so as to yield the desired performance.
[0126] The collet lock 13 is preferably made of a plastic featuring
a low coefficient of friction, so as to both smoothly manipulate
the outer collet 45 and to act as a forward guide for the
reciprocating longitudinal movement of nose 9.
[0127] The front end cap is preferably made of a high-strength
aluminum alloy to provide the necessary strength and wear
characteristics while simultaneously minimizing weight.
[0128] Returning, finally, and briefly, to FIG. 1, it will be
appreciated that rivet 3a is shown in the "rivet ready" position,
with nose assembly 43 fully extended, and the next rivet in
succession, rivet 3b, obscured from view, is still contained within
the clip-fed rivet delivery system 7, awaiting its turn to be
presented to the nose assembly 43 after rivet 3a has been installed
and nose assembly 43 has been retracted/reciprocated to the
rear.
[0129] From an automation/computerized control standpoint, the
preferred embodiment of collet lock air cylinder 61 (as well as
presentation air cylinder 33 and reciprocation air cylinder 21
referred to hereinbelow) is an air cylinder system which emits
feedback signals to the system controller verifying the actual
position of the air cylinder so as to facilitate effective control.
For example, some air cylinder systems are referred to colloquially
in the industry as "magnetic air cylinders" in that they feature
the use of magnetic rings and sensors (e.g., hall effect sensors)
to generate feedback signals which are easily interpreted by the
system controller. Through the use of these kinds of systems, or
their equivalents, the locked/unlocked condition of the outer
collet 45 can be precisely and continuously controlled.
[0130] Stage Two: Inner Collet Closure.
[0131] Turning now to FIG. 2, the blind rivet installation tool 5
is shown in its position/state during stage two of the blind rivet
installation process. This stage features complete inner collet
closure and shoulder engagement, as more fully described below.
[0132] Referring to FIG. 2, the reader will appreciate, based upon
the description provided above, that the collet lock 13 and outer
collet 45 are in their respective locked positions. An
understanding of the operation of the blind rivet installation tool
5 in stage two is best developed by reference to a number of the
tool components positioned in a more rearward location within the
tool, as shown in FIG. 2A.
[0133] Referring, now, to FIG. 2A, the reader will observe that
piston 91 has been displaced in a rearward direction from front end
cap 15 as a result of the introduction of hydraulic fluid into
piston cavity 109.
[0134] At stage one, the piston 91 is abutted to front end cap 15.
At stage two, shortly after trigger 29 is actuated, hydraulic fluid
is introduced at high pressure into piston cavity 109. As a result,
piston cavity 109 expands and piston 91 translates rearward to the
position shown in FIG. 2A.
[0135] As piston 91 translates rearward, its frusto-conical surface
91a impinges upon the forward frusto-conical surfaces of inner
collet 93.
[0136] Inner collet 93 consists of a plurality of inner collet
members acted upon by a plurality of inner collet springs. In the
preferred embodiment shown herein, there are two inner collet
members, inner collet member 93a and inner collet member 93b. Inner
collet member 93a and inner collet member 93b are centered about
nose axis 89, and are urged in a radially outward direction by a
plurality of inner collet springs 111; in the preferred embodiment
shown herein, this is effectuated by inner collet springs 111a,
111b, 111c, and 111d. Compare FIG. 15 (which depicts inner collet
93 in its open, outwardly radially expanded, position) with FIG. 16
(which depicts inner collet 93 in its closed, inwardly radially
contracted, position).
[0137] Returning, now, to FIG. 2A, inner collet member 93b features
a forward frusto-conical surface 93b(1) and a rearward
frusto-conical surface 93b(2). As piston 91 translates rearward,
its frusto-conical surface 91a impinges upon the forward
frusto-conical surfaces 93a(1) and 93b(1) of inner collet 93, and,
in turn, the rearward frusto-conical surfaces 93a(2) and 93b(2) of
inner collet 93 impinge upon inner collet spring follower 95 at
inner collet spring follower frusto-conical surface 95a.
[0138] As piston 91 translates rearward, and its frusto-conical
surface 91a impinges upon the forward frusto-conical surfaces
93a(1) and 93b(1), inner collet member 93a and inner collet member
93b are translated rearward and simultaneously radially compressed
inward as they are slidably re-positioned deeper within the
frusto-conical piston surface 91a and inner collet spring follower
frusto-conical surface 95a. This rearward translation and radial
compression continues until the inner collet 93 reaches its fully
closed position as shown in FIG. 2A and FIG. 16.
[0139] An inspection of FIG. 15 and FIG. 16, depicting the shape of
inner collet 93 in its open and closed positions respectively,
reveals that each inner collet member features no less than eight
major utilitarian surfaces. Inner collet member 93b, for example,
features: [0140] (a) forward frusto-conical surface 93b(1); [0141]
(b) rearward frusto-conical surface 93b(2); [0142] (c) inner
cylindrical surface 93b(3); [0143] (d) outer cylindrical surface
93b(4); [0144] (e) first mating surface 93b(5); [0145] (f) second
mating surface 93b(6); [0146] (g) forward bearing surface 93b(7);
and [0147] (h) rearward bearing surface 93b(8).
[0148] When inner collet 93 is fully closed, as shown in FIG. 2A
and FIG. 16, the inner collet members have been inwardly radially
compressed to such a complete extent that the mating surfaces of
the inner collet members fully meet. In the embodiment shown, the
mating surfaces of inner collet member 93a (i.e., the first mating
surface 93a(5) and second mating surface 93a(6)) meet with the
mating surfaces of inner collet member 93b (i.e., the first mating
surface 93b(5) and second mating surface 93b(6)).
[0149] Furthermore, the inner collet members have been inwardly
radially compressed to such a complete extent that the inner collet
member inner cylindrical surfaces, such as inner collet member
inner cylindrical surface 93b(3), approach and loosely, but
closely, fit about and opposite the outer cylindrical surface of
pull rod 55.
[0150] It should also be understood that, when the inner collet
members have been fully inwardly radially compressed as shown, the
inner collet rearward bearing surface 93b(8) has been radially
re-positioned such that it is now in a longitudinally oppositional
position with respect to the forwardmost bearing surface 101a of
pull rod coupling 101. In particular, note that the inner collet
rearward bearing surface 93b(8) has been brought radially within
the reach of the forwardmost surface 101a of pull rod coupling 101
(pull rod coupling 101 being threadedly affixed to pull rod 55);
thus, in stage three, as additional hydraulic fluid is introduced
under high pressure into piston cavity 109, the inner collet
rearward bearing surface 93b(8) will impinge upon the forwardmost
bearing surface 101a of pull rod coupling 101.
[0151] At this point, several things about inner collet 93 can be
appreciated.
[0152] When inner collet 93 is in its fully closed position, as
shown in FIG. 2A and in FIG. 16, it doesn't clamp upon pull rod 55;
rather, it is loosely fitted about pull rod 55. The key to the
effective use of inner collet 93 is that, when it is compressed to
its fully closed position, a substantial and effective surface area
within inner collet rearward bearing surface 93b(8) is brought into
effective oppositional alignment with the forwardmost bearing
surface 101a of pull rod coupling 101. Similarly, when it is
compressed to its fully closed position, the inner collet member
forward bearing surfaces, such as inner collet member forward
bearing surface 93b(7), meet a substantial and effective surface
area within the rearward bearing surface 91b of piston 91.
[0153] When inner collet 93 is translated rearward by the action of
piston 91, it is actuating spring 97 (constrained by rear end cap
99 which is threadedly connected to hydraulic cylinder 17) that
provides the resistance which results in the inner collet 93 being
simultaneously radially compressed inward as it is slidably
re-positioned deeper within the frusto-conical piston surface 91a
and inner collet spring follower frusto-conical surface 95a. Thus,
it is essential to pre-set the spring constant of actuating spring
97 such that it is much greater than the spring constant of the
inner collet springs 111, so that the inner collet 93 rapidly
closes and opens during the cyclic rearward and forward motion of
piston 91 with a minimal amount of piston stroke.
[0154] Another salient feature of inner collet 93 is its unique
shape. See FIG. 15 and FIG. 16. As discussed herein, inner collet
93 moves back and forth between its open position (i.e., its
forward, outwardly radially expanded, position, e.g., at stage one)
as shown in FIG. 15 and its closed position (i.e., its rearward,
inwardly radially compressed, position, e.g., at stage two) as
shown in FIG. 16. The shape of inner collet 93 (i.e., the shape of
the inner collet members, such as, in the embodiment shown in this
specification, inner collet member 93a and 93b) is driven by the
desired shape of inner collet 93 at its respective open and closed
positions as well as by its desired performance between these two
points.
[0155] In its open position, as shown in FIG. 6, FIG. 6A, and FIG.
15, and focusing specifically upon the forward portions of inner
collet member 93b, it is desired for forward frusto-conical surface
93b(1) to effectively meet the radially outer portion of piston
rearward frusto-conical surface 91a. By contrast, in its closed
position, as shown in FIG. 2 and FIG. 16, and focusing specifically
upon the forward portions of inner collet member 93b, it is desired
for forward frusto-conical surface 93b(1) to effectively meet the
radially inner portion of piston rearward frusto-conical surface
91a. It is also desired for inner collet 93 to smoothly glide
between these two states as it is cyclically reciprocated between
its open and closed positions.
[0156] Finally, returning to the overall state of blind rivet
installation tool 5 at stage two, it should be noted that, although
hydraulic fluid has entered piston cavity 109, and piston 91 has
stroked rearward, resulting in inner collet 93 translating rearward
and closing radially inwardly to its fully closed position, pull
rod coupling 101 and pull rod 55 have not, as yet, moved
longitudinally.
[0157] From an automation/computerized control standpoint, it is
helpful to configure the system controller so that, if the operator
of the tool releases the trigger 29 at any point prior to stage
four (which occurs immediately after pintail break), the system
controller initiates a controlled abort or reset of the
installation process. For example, in such a case, the system
controller would initiate a controlled reduction/release of
hydraulic pressure, and the piston return techniques described in
stage five and stage six would be employed.
[0158] Stage Three: Rivet Installation Complete Except for Pin
Break.
[0159] Turning, now, to FIG. 3, FIG. 3A, and FIG. 3B, the blind
rivet installation system 1 is shown at stage three in the blind
rivet installation process; that is, the blind rivet installation
system 1 is shown in the state experienced when the installation of
rivet 3 is nearly complete except for pin break (i.e., the breaking
of the rivet pintail that occurs at the conclusion of rivet
installation).
[0160] FIG. 3 (which reveals blind rivet installation system 1
status at stage three) is probably most easily understood and
appreciated by a comparative study of it alongside FIG. 2 (which
reveals blind rivet installation system 1 at stage two). Note that,
in FIG. 3, and as particularly depicted in FIG. 3A, pull rod
assembly 73, bridge 19, bridge coupling 107, retention nut 105, and
reciprocation air cylinder extension rod 113 have been
longitudinally displaced in a rearward direction relative to their
respective positions shown in FIG. 2.
[0161] The displacement of pull rod assembly 73 has occurred over
substantial resistance. The ultimate source of resistance: the
rivet 3a.
[0162] Recall that, at stage one, as shown in FIG. 1A, the pull rod
assembly 73 is in its forwardmost position. At that position, the
forward face of jaws 49 impinges upon the rearmost face of nose
insert 11; this action results in jaws 49 opening (i.e., extending
radially outward), and translating backward with respect to jaw
collet 47, the radially outward expansion opening the jaws 49
sufficiently (to the "rivet acceptance position") to receive the
pintail of a rivet 3.
[0163] Now, at stage three, as shown in FIG. 3 and FIG. 3B, as the
pull rod assembly 73 is translated towards the rear, the segmented
jaws 49 now close (i.e., inwardly radially compress) upon the
pintail 3a(1) of rivet 3a. Furthermore, as the translation of pull
rod assembly 73 continues, the inwardly radially compressive force
of the jaw collet 47 increases, thus increasing the substantially
normal force (i.e., the "bite") the jaw collet 47 and the jaws 49
exert upon the pintail 3a(1) of rivet 3a.
[0164] Increases in the inwardly radially compressive force of jaw
collet 47 and jaws 49 continue to occur as additional fluid is
introduced under high pressure into piston cavity 109, which, as
shown in FIG. 3, further rearwardly displaces pull rod assembly 73
thus increasing the longitudinal pulling force being exerted by the
pull rod assembly 73 upon rivet 3a. The additional hydraulic fluid
in piston cavity 109, and the displacement of pull rod assembly 73,
is most easily recognized in FIG. 3 and FIG. 3A by noting, as
compared with FIG. 2, the increased longitudinal distance between
front end cap 15 and piston 91. The rearward displacement of pull
rod assembly 73 is also evidenced by the compression of actuating
spring 97 as also shown in FIG. 3 and FIG. 3A.
[0165] Rivets 3 are designed to deform under the influence of the
pulling force generated by the pull rod assembly 73, and, in FIG.
3B, the deformation of rivet 3a is apparent in the region
designated as deformation region 3a(2). This deformation, in fact,
is what secures the rivet 3a in place and enables the performance
of a "blind" installation (i.e., installation performed by
immediately accessing only one physical side/face of the members to
be joined) of the rivet 3a.
[0166] From an automation/computerized control standpoint, it is
helpful to note that sensors continuously monitor the building
hydraulic pressure which characterizes this stage. If abnormalities
in the expected time-sequenced build and release of pressure occur,
the system controller initiates a controlled abort or reset of the
installation process. For example, if the hydraulic pressure
profile occurs as expected (i.e., the hydraulic pressure builds as
expected), then, if, for some reason, pintail break is unduly
delayed, a controlled abort or reset of the installation process is
executed by the controller. If, for example, the hydraulic pressure
profile is abnormal (e.g., the pressure builds unusually slowly as
it might if no rivet pintail was in position within nose insert 11
at the time the trigger 29 was depressed), then, again, a
controlled abort or reset of the installation system may be
effectuated.
[0167] Stage Four: Rivet Installation Post Pin Break.
[0168] Turning, now, to FIG. 4, the blind rivet installation system
1 is shown at stage four in the blind rivet installation process;
that is, the blind rivet installation system 1 is shown in the
state experienced immediately after the installation of rivet 3 is
completed and pintail break occurs.
[0169] The events immediately following pintail break are
graphically depicted in FIG. 4. The reader will recall that, during
stage three, as described hereinabove, pintail portion 3a(l) of
rivet 3a has been pulled rearward with great force by jaws 49; at
this instant in time, at stage four, immediately after pintail
break occurs, pintail portion 3a(1) of rivet 3a has been
accelerated rearward, released by jaws 49, and is thereby projected
rearward at high speed through blind rivet installation tool 5
within the pull rod inner cavity 115 of pull rod 55 as shown in
FIG. 4.
[0170] At this point in time after pintail break, pull rod assembly
73, now freed of the resistance provided by rivet 3a, translates
rearward at high speed. This high-speed rearward translation can be
readily appreciated in FIG. 4 by inspection of the displacement of
bridge 19 from rear end cap 99. Similarly, a clear rearward
displacement of the pull rod assembly 73 is evident from the
distance between the forwardmost face 101a of pull rod coupling 101
from the rearward bearing surface 93b(8) of inner collet 93.
[0171] As the pull rod assembly 73 translates backward, it is
rapidly, but smoothly, decelerated by the action of dampening
spring 59. Dampening spring 59 fulfills one of its intended
functions in dampening the shock, or "recoil", associated with
pintail break as a result of its being secured between the
dampening spring pull rod stop 117 (located on the forward exterior
surface of pull rod 55) and the dampening spring nose stop 119
(located on the rearward interior surface of nose 9). This spring
is preferably manufactured of high-strength spring steel, and it is
believed that dampening spring 59 will enjoy a long useful life if
it is designed so that, at the point of maximum compression (which
occurs during recoil), it is compressed to no more than
approximately forty percent of its at-rest length.
[0172] It should also be noted that pull rod assembly 73 is
threadedly connected to bridge 19 which is, in turn, and in
functional succession, connected to bridge coupling 107 and
reciprocation air cylinder extension rod 113 of reciprocation air
cylinder 21. Reciprocation air cylinder 21, as described more fully
below, is useful in stage eight in effectuating reciprocation of
the nose assembly 43. However, it is also useful here.
[0173] By metering the valve assemblies associated with
reciprocation air cylinder 21, in accordance with means well-known
to persons of ordinary skill in the art, it is possible to use
reciprocation air cylinder 21 to assist dampening spring 59 in
managing the pull rod assembly 73 movement that occurs after
pintail break. For example, some dampening can be derived as an
immediate result of the work being done in translating the at-rest
reciprocation air cylinder piston rearward. The dampening can be
increased if the reciprocation air cylinder 21 is pressurized so
that the translation requires additional work; indeed, even the
nature of the dampening (e.g., linear, non-linear) can be varied
through metering the valve assemblies associated with reciprocation
air cylinder 21, all in accordance with means well-known to persons
of ordinary skill in the art.
[0174] In addition to dampening through the use of dampening spring
59 and/or the use of reciprocation air cylinder 21, dampening may
be effected through the use of seals which serve to create a
substantially airtight rearward cavity within blind rivet
installation tool 5.
[0175] Inspection of FIGS. 3A, 4, and 5A, reveals a rearward cavity
defined by nose 9, forward pull rod outer seal 57, nose-piston seal
121, piston 91, rear end cap outer seal 135, piston flange
hydraulic seal 133, hydraulic cylinder 17, rear end cap 99, rear
end cap inner seal 123, pull rod coupling sealing tube 103, pull
rod 55, and pull rod coupling 101. A careful inspection of the
embodiment shown in FIG. 3A and FIG. 4 reveals that the rearward
cavity is not an airtight cavity due in large part to the lack of a
sliding engagement between closely fitted nose 9 and piston 91, the
sliding engagement to be sealed by nose-piston seal 121 acting
against piston bushing 137 which is press fit into the inner
surface of piston 91.
[0176] Thus, if, in an alternative embodiment, a sliding engagement
were arranged between closely fitted nose 9 and piston 91
throughout stage four, stage five and stage six, then a third major
alternative source of dampening (i.e., dampening via compression of
the trapped volume of air within the substantially airtight
rearward cavity) would exist. An air supply air fitting (not
shown), located in hydraulic cylinder 17 at a longitudinal location
just forward of rear end cap 99, facilitates the management of the
air pressure in the rearward cavity, so that, via the air supply,
the desired time-sequenced amount of air compression occurs during
the rearward translation of pull rod assembly 73.
[0177] At this point in time, immediately after pintail break, due
to the pintail break-generated drop in resistance, the hydraulic
pressure in the hydraulic line and hydraulic cylinder drops rapidly
and dramatically. A hydraulic pressure sensor (not shown) in the
hydraulic fluid supply detects the pressure drop, and, in response,
the hydraulic valve is switched, diverting the hydraulic fluid flow
from the hydraulic line to reservoir; the hydraulic line supplying
hydraulic fluid to piston cavity 109 is also re-directed to the
hydraulic system reservoir. Actuation spring 97, now acting through
spring follower 95, urges inner collet 93 and piston 91 forward,
reducing the size of piston cavity 109, and urging the hydraulic
fluid contained therein into the reservoir.
[0178] After pull rod assembly 73 has completed its backward
translation, it is desired for it to return expeditiously to its
fully forward position; however, returning pull rod assembly 73 to
its fully forward position is a step that is desirably effectuated
with some care, as excessive return speed will result in a
needlessly strong impact between the forwardmost surface 101a of
pull rod coupling 101 and the rearward bearing surfaces (e.g.,
rearward bearing surface 93b(8)) of inner collet 93. Furthermore,
the time-limiting step in the blind rivet installation cycle at
this point is the return (by mechanisms to be discussed) of piston
91, and not pull rod assembly 73, to its return position.
[0179] Thus, while it is desired to return pull rod assembly 73 to
its fully forward position expeditiously, if this return is
effected by means of dampening spring 59, as it is the embodiment
shown herein, then, as described above, it may well be desired to
retard the forward movement of pull rod assembly 73 somewhat. This
can be effectuated through a number of mechanisms. First, it may be
possible to meter the valve assemblies associated with
reciprocation air cylinder 21, in accordance with means well-known
to persons of ordinary skill in the art, to dampen the forward
return speed of pull rod assembly 73.
[0180] Second, it may also be possible, in the alternative
embodiment described above (i.e., the embodiment featuring a
substantially airtight rearward cavity), to meter the air supply
valving associated with the air supply air fitting in hydraulic
cylinder 17 so as to restrict air flow into the substantially
airtight rearward cavity thereby dampening the forward return
motion of pull rod assembly 73.
[0181] A variety of issues from an automation/computerized control
standpoint have been identified in the description of this stage.
The attentive reader will also appreciate that the valving
associated with the reciprocation air cylinder 21 has been usefully
configured such that air pressure only acts upon the air cylinder
21 during reciprocation; that is, once the air cylinder piston has
been stroked to its desired new position, the associated air valve
releases the air pressure on the air cylinder. This enables the
above-referenced metering of the valve assemblies associated with
reciprocation air cylinder 21.
[0182] Stage Five: Inner Collet Re-Opening.
[0183] Turning, now, to FIG. 5, the blind rivet installation system
1 is shown at stage five in the blind rivet installation process;
that is, the blind rivet installation system 1 is shown in the
state experienced after pintail break occurs, at a time when the
pull rod assembly 73 has fully returned to its forwardmost
position, the piston 91 is in the process of returning to its
forwardmost position, and the inner collet 93 is in the process of
re-opening.
[0184] The attentive reader will recall that, after pull rod
assembly 73 has completed its backward translation, it is then
translated to its fully forward position. This may be accomplished
in several ways, and, in the preferred embodiment shown herein, it
is effectuated in no small part by means of the dampening spring
59.
[0185] As referenced above, the return of the pull rod assembly 73
to its fully forward position is a step that should be effectuated
with some care, as excessive return speed will result in a
needlessly strong impact between the forwardmost surface 101a of
pull rod coupling 101 and the rearward bearing surfaces (e.g.,
rearward bearing surface 93b(8)) of inner collet 93. In FIG. 5,
this impact has, in fact, already occurred, and, as shown, inner
collet 93 is continuing its forward return, while pull rod assembly
73 has reached its fully returned, forwardmost position. Perhaps
the best evidence of the full and complete return of pull rod
assembly 73 is the fact that, as was depicted in FIG. 1A and is now
depicted in FIG. 5B, the forward face of jaws 49 now impinges upon
the rearmost face of nose insert 11 resulting in jaws 49 opening
(i.e., extending radially outward) sufficiently (to the "rivet
acceptance position") to receive the pintail of a rivet 3. The
reader will also note the fully expanded condition of dampening
spring 59.
[0186] Although, at this moment in time, the pull rod assembly 73
has returned to its forwardmost position, inner collet 93 and
piston 91 have not, as yet, fully returned to their respective
forwardmost positions. At this point, actuation spring 97, acting
through inner collet spring follower 95, is continuing to urge
inner collet 93, and thereby piston 91, forward (note the partially
radially expanded condition of inner collet 93). The actuation
spring 97, at this point, has almost fully expanded and, as a
result, the force it imparts to inner collet spring follower 95 is
substantially diminishing. If the returns of inner collet 93 and
piston 91 were left entirely to the work of actuation spring 97,
the return completion time might be excessive; therefore, to reduce
return completion time, at the time after pintail break when the
hydraulic pressure sensor in the hydraulic fluid supply detects the
pintail break-generated pressure drop, or very shortly thereafter,
the air supply pressurizes the now substantially airtight rearward
cavity (note the sliding engagement of closely fitted nose 9 and
piston 91 in FIG. 5 and FIG. 5A) so as to expedite the forward
movement of piston 91.
[0187] From an automation/computerized control standpoint, it is
helpful to note that the return of the pull rod assembly 73 to its
fully forward position is an event which could practically be
evidenced by the feedback signal(s) (e.g., the hall effect signals)
from reciprocation air cylinder 21.
[0188] Stage Six: Piston Return Complete.
[0189] Turning, now, to FIG. 6, the blind rivet installation system
1 is shown at stage six in the blind rivet installation process;
that is, the blind rivet installation system 1 is shown in the
state experienced after pintail break occurs, at a time when the
pull rod assembly 73 has fully returned to its forwardmost
position, the piston 91 has fully returned to its forwardmost
position, and the inner collet 93 has fully re-opened.
[0190] Note, in both FIG. 6 and FIG. 6A, that the forwardmost face
91c of the piston flange of piston 91 is fully coincident with the
rearmost face of front end cap 15. Note, as well, that actuation
spring 97 has fully expanded.
[0191] Finally, from an automation/computerized control standpoint,
in FIG. 6A, note the presence of a piston proximity sensor 139
(commonly, a transducer) used to detect the full return of piston
91. The piston proximity sensor 139 may be fitted to front end cap
15 as shown.
[0192] Stage Seven: Outer Collet Opens.
[0193] Turning, now, to FIG. 7, the blind rivet installation system
1 is shown at stage seven in the blind rivet installation process;
that is, the blind rivet installation system 1 is shown in the
state experienced after pintail break occurs, at a time when the
pull rod assembly 73, the piston 91, and the inner collet 93 have
returned to their forwardmost positions; thus, at this juncture,
the blind rivet installation tool 5 is ready to effectuate
reciprocation of the nose assembly 43. In order for reciprocation
of nose assembly 43 to occur, however, the outer collet 45 must be
unlocked/opened.
[0194] The reader will recall, from the extensive discussion of
stage one, how the outer collet 45 operates. In a nutshell, when
air cylinder 61 is extended, collet lock bracket 41 rotates
counter-clockwise (as viewed from the vantage point of FIG. 1B
along the z-axis). When collet lock bracket 41 is so rotated, the
collet lock bracket tongs 77 urge the collet lock 13 forward. As
described more fully in the discussion of FIG. 1C and FIG. 1D, the
forward movement of collet lock 13 results in outer collet 45 being
translated forwards and radially expanded, so that, as shown in
FIG. 1D and in FIG. 7, the outer collet 45 translates to its fully
unlocked position. At this point, nose assembly 43 can reciprocate
through outer collet 45 without interference.
[0195] Stage Eight: Reciprocation: Nose Assembly Retracted; Rivet
Captured at Paw Stop.
[0196] Turning, now, to FIG. 8, the blind rivet installation system
1 is shown at stage eight in the blind rivet installation process;
that is, the blind rivet installation tool 5 is shown in the state
experienced after the nose assembly has fully retracted, with a
rivet "captured" and held (as described below) at a paw stop
location prior to presentation.
[0197] As shown in FIG. 8, nose assembly 43 has been fully
retracted rearward by the action of reciprocation air cylinder 21.
Notice the rearward location of nose assembly 43, bridge 19, bridge
coupling 107, and reciprocation air cylinder extension rod 113.
Once it is confirmed by piston proximity sensor 139 that piston 91
has been fully returned, as described in stage six, and the outer
collet has been opened, as described in stage seven, the
reciprocation air cylinder 21 extends the reciprocation air
cylinder extension rod 113 so as to translate nose assembly 43
rearward through the action of bridge coupling 107 and bridge
19.
[0198] Attention is now directed to FIG. 8A, FIG. 8B, FIG. 8C, and
FIG. 8D. These figures provide additional detail regarding various
aspects of the clip-fed rivet delivery system 7 absent the clip-fed
rivet delivery system structural housing 141 (which comprises rivet
body structural housing 141a and rivet pintail structural housing
141b).
[0199] Turning, now, to FIG. 8A, the next rivet in succession rivet
3b is shown in its position in stage eight just prior to
presentation (rivet presentation occurring during stage nine). The
rivet 3b is fully "captured" (i.e., secured for later presentation)
within rivet body presenter 143 and rivet pintail presenter 145.
Specifically, captured rivet 3b is fully seated and snapped into
rivet body presenter channel 143a and rivet pintail presenter
channel 145a (the rivet presenter channels also depicted in FIG. 9A
and FIG. 13).
[0200] In FIG. 8A, as stated above, nose 9 has been fully
longitudinally retracted rearward. This rearward retraction of nose
9 allows the spring-loaded paw stop actuators 151 to extend
radially inward (i.e., towards nose axis 89) to their fully
extended (i.e., "disengaged") position. Note: in FIG. 8A, the
supports which hold paw stop actuators (which, in the preferred
embodiment, are paw stop actuators 151a and 151b) in place have
been removed from the figure for clarity.
[0201] The extension/disengagement of paw stop actuators 151 allows
the spring-loaded paw stop assemblies 149 to retract rearward
(i.e., to "disengage"). Notice the sliding engagement of the
rearmost face of paw stop assemblies 149a and 149b against the
conical surface of corresponding paw stop actuators 151. Note: in
FIG. 8A, the supports which hold paw stop assemblies 149 in place
have been removed from the figure for clarity.
[0202] The disengagement of the paw stop assemblies 149, as
depicted in FIG. 8A and as occurs during stage eight, allows the
rivet pintail paws 147 to rotate freely about their rivet pintail
paw pivots 153 (not shown for clarity), although it should be noted
that the rivet pintail paws 147a and 147b are spring-loaded so that
the paw extremities rotate generally downwards to the closed
position shown (i.e., rivet pintail paw 147a is spring-loaded to
perform clockwise rotation when viewed facing in the positive
direction of the x-axis while rivet pintail paw 147b is
spring-loaded to perform counter-clockwise rotation). When, at
other times during the blind rivet installation cycle, the paw stop
assemblies 149 are engaged (i.e., fully extended forward and over
the rivet pintail paws 147), the rivet pintail paws 147 are thereby
blocked/precluded from rotating generally upwards so as to preclude
presentation of a later rivet in succession (i.e., rivet pintail
paw 147a is precluded from performing counter-clockwise rotation
while rivet pintail paw 147b is precluded from performing clockwise
rotation).
[0203] Thus, as shown in FIG. 8A, while the rivet pintail paws 147
are shown in their spring-actuated closed position, the
disengagement of the paw stop assemblies 149 allows the rivet
pintail paws 147 to rotate generally upwards (i.e., to "open") at a
later time (at stage nine) when rivet presentation occurs.
[0204] FIG. 8C, like FIG. 8A, clarifies the spatial arrangement of
the rivet pintail paw 147, paw stop assembly 149, and paw stop
actuator 151.
[0205] As shown in FIG. 8A, the rearward retraction of nose 9
allows the spring-loaded paw stop actuators 151 to extend radially
inward (i.e., towards nose axis 89) to their fully extended (i.e.,
"disengaged") position. The extension/disengagement of paw stop
actuators 151 allows the spring-loaded paw stop assemblies 149 to
retract rearward (i.e., to "disengage").
[0206] Notice in FIG. 8C the components of the paw stop assembly
149a and its relationship to rivet pintail paw 147a and paw stop
actuator 151a. When nose 9 reciprocates forward (not shown), the
paw stop actuator 151a is actuated/engaged (i.e., depressed, or
extended radially outward with respect to nose axis 89).
Specifically, the exterior surface of nose insert 11 and then nose
9 comes into effective sliding engagement with, and thus
depresses/actuates, paw stop actuator end cap 151a(1). As paw stop
actuator 151a is depressed, paw stop actuator conical surface
151a(5) slidably and effectually engages paw stop assembly end cap
149a(6) (whose orientation is fixed by clip-fed rivet delivery
system structural housing 141b (not shown)) and translates paw stop
assembly 149a forward. The forward translation of paw stop assembly
149a extends paw stop 149a(1) longitudinally forward to a position
over rivet pintail paw 147a, specifically to a position vertically
over the upper surface 147a(1) of rivet pintail paw 147a. With the
paw stop assembly 149a in this position, the extremity of rivet
pintail paw 147a cannot rotate upward because the upper surface
147a(1) of rivet pintail paw 147a strikes the outer cylindrical
surface of paw stop assembly 149a at paw stop 149a(1).
[0207] Conversely, when nose 9 reciprocates backwards (e.g., to the
position shown in FIG. 8A), the paw stop actuator 151a is
disengaged. Specifically, nose 9 exits sliding engagement with, and
thus releases/disengages, paw stop actuator end cap 151a(1). As
spring-actuated paw stop actuator 151a is released/extended, paw
stop assembly end cap 149a(6) (whose general orientation is fixed
by clip-fed rivet delivery system structural housing 141b (not
shown)) smoothly extends and follows paw stop actuator outer
cylindrical surface 151a(2) and then paw stop actuator conical
surface 151a(5) (featuring a decreasing conical outer diameter)
until paw stop assembly 149a reaches full rearward
extension/disengagement. At this point, paw stop 149a(1) has also
been translated longitudinally rearward to a position adjacent to,
but not over, the upper surface 147a(1) of rivet pintail paw 147a,
so that it does not interfere with the rotation of rivet pintail
paw 147a.
[0208] FIG. 8B provides information regarding how paw stop
actuators 151 and paw stop assemblies 149 are positionally secured
within clip-fed rivet delivery system structural housing 141b.
[0209] The components of paw stop actuator 151b, for example, are
shown ready for insertion within paw stop actuator recess 155. Paw
stop actuator spring 151b(3) abuts a stop within recess 155, so
that paw stop actuator 151b's body (which may be constructed as a
single unit or in parts) is continuously urged radially inward
(with respect to nose axis 89) and restrained only by a stop, such
as an e-clip, transversely secured within clip-fed rivet delivery
system structural housing 141b.
[0210] The components of paw stop assembly 149b, for example, are
shown ready for insertion within paw stop assembly recess 157. Paw
stop assembly return spring 149b(2) abuts a stop within recess 157,
so that paw stop assembly 149b's body is continuously urged
rearward and restrained only by the outer functional surfaces of
its associated paw stop actuator (i.e., paw stop actuator
cylindrical surface 151b(2) and paw stop actuator conical surface
15lb(5)).
[0211] FIG. 8D provides useful additional detail regarding paw stop
assembly 149, by providing a cutaway view of paw stop assembly
149a. Paw stop assembly 149a comprises paw stop 149a(1) (which
features a paw stop flange 149a(5)), paw stop return spring
149a(2), paw stop sleeve 149a(3) (which features a paw stop sleeve
end portion 149a(6)), and paw stop compression spring 149a(4).
[0212] The purpose of the two springs within paw stop assembly 149a
becomes apparent when the reader understands that the paw stop will
be actuated under two different circumstances. In stage thirteen,
for example, when paw stop assembly 149a is actuated/engaged, the
paw stop 149a(1) extends over the paw 147a, preventing its
generally upwards rotation. In this circumstance, the forward
movement of paw stop sleeve end cap portion 149a(6) compresses the
relatively stiff compression spring 149a(4) which, in turn,
impinges upon the paw stop flange 149a(5) which, in turn, urges the
paw stop 149a(1) forward against the relatively gentle resistance
of return spring 149a(2) (the return spring 149a(2) being secured
against forward translation by a stop within clip-fed rivet
delivery system structural housing 141b).
[0213] In stage ten, by contrast, when paw stop assembly 149a is
actuated, the paw stop 149a(1) is extended forward and it abuts the
rearmost face of paw 147a. In this circumstance, the forward
movement of paw stop sleeve end cap portion 149a(6) compresses the
relatively stiff compression spring 149a(4) which, in turn,
impinges upon the paw stop flange 149a(5) which, in turn, urges the
paw stop 149a(1) forward. In this case, however, forward movement
of paw stop 149a(1) is blocked, and, as a result, compression
spring 149a(4) is compressed.
[0214] From an automation/computerized control standpoint, it is
helpful to note that the reciprocation of nose assembly 43 to its
fully rearward position is an event which could practically be
evidenced by the feedback signal(s) (e.g., the hall effect signals)
from reciprocation air cylinder 21.
[0215] Stage Nine: Reciprocation: Rivet Presentation.
[0216] Turning, now, to FIG. 9, the blind rivet installation system
1 is shown at stage nine in the blind rivet installation process;
that is, the blind rivet installation tool 5 is shown in the state
experienced after the nose assembly has fully retracted, with a
rivet "presented" for subsequent loading by and within the nose
assembly.
[0217] The reader will recall, with reference to FIG. 1, that
presentation air cylinder 33, turnbuckle 35, and presentation
connecting rod 37 are visible through access portal 31 and are
shown in a substantially retracted/rearward position. Also visible
is large presentation sprocket 39 which is connected to
presentation connecting rod 37 via dowel pin 71. Large presentation
sprocket 39 rotates back (i.e., clockwise from the vantage point of
FIG. 1) and forth (counterclockwise) between two endpoint loci
during operation of the blind rivet installation tool 5; at stage
one, the position of large presentation sprocket 39 is best
described as being nearly fully clockwise rotated.
[0218] Returning, now, to FIG. 9, which is associated with stage
nine of the blind rivet installation process, the reader will
observe that clip-fed rivet delivery system structural housing 141
and gear drive housing 27 have been removed so as to facilitate a
review of the presentation mechanisms associated with the clip-fed
rivet delivery system 7. Note that presentation air cylinder 33,
turnbuckle 35, and presentation connecting rod 37 are now in a
fully retracted/rearward position, and large presentation sprocket
39 is fully clockwise rotated. A careful study of FIG. 9A (and an
understanding of the rivet presentation process which occurs at
stage nine) reveals why this is so.
[0219] Referring to FIG. 9A, it is readily observed that rivet 3b
has been "presented" (or, elevated) to a precise central location
for subsequent loading within nose assembly 43. Notice that the
longitudinal axis of rivet 3b is nearly co-extensive with the nose
axis 89. Presentation at this location is desired because, at a
subsequent time, nose assembly 43 will be reciprocated forward so
as to load rivet 3b within nose assembly 43.
[0220] The presentation of rivet 3b described above is accomplished
through the action of rivet body presenter 143 and rivet pintail
presenter 145. Recall that rivet 3b is securely held by both of
these presenters by virtue of the snapping engagement that exists
between the body of rivet 3b and rivet body presenter channel 143a
and between the pintail of rivet 3b and rivet pintail presenter
channel 145a.
[0221] As stated above, the rivet body presenter 143 and rivet
pintail presenter 145 have been configured, and specifically
cooperate, so that, at stage nine, rivet 3b can be properly
presented to nose assembly 43 for loading. FIG. 9A reveals, as
described above, that rivet body presenter 143 and rivet pintail
presenter 145 are aligned so that their respective presenter
channels, when presenting a rivet, present the rivet so that its
longitudinal axis aligns with nose axis 89.
[0222] Furthermore, just as the nose assembly reciprocates
(horizontally) at various stages of blind rivet installation tool 5
operation, so too do the rivet body presenter 143 and rivet pintail
presenter 145 reciprocate (vertically) at various stages of the
blind rivet installation process. Rivet body presenter 143 and
rivet pintail presenter 145 are slidably secured to the clip-fed
rivet delivery system structural housing 141b and clip-fed rivet
delivery system guide track assembly 171.
[0223] Rivet presentation is effectuated as follows. Presentation
air cylinder 33 retracts turnbuckle 35 and, as a result,
presentation connecting rod 37 to their fully retracted/rearward
positions. This has the effect of fully clockwise rotating large
sprocket hub 159 and thereby large presentation sprocket 39. The
clockwise rotation of large presentation sprocket 39 drives
presentation chain 161 which, in turn, drives small presentation
sprocket 163 (also in a clockwise direction as viewed in the
positive z-direction). Small presentation sprocket 163 is fixed to
presentation gear 165, and its clockwise rotation rotates
presentation gear 165 clockwise. The clockwise rotation of
presentation gear 165 translates presentation rack 167 upwards
(i.e., in the positive y-axis direction).
[0224] Because presentation rack 167 is fixed to pintail presenter
145, the elevation of presentation rack 167 thereby raises pintail
presenter 145. This explains the full and final elevation of
pintail presenter 145 to presentation position.
[0225] Rivet body presenter 143 is elevated not by the direct
action of presentation rack 167, but, rather, by the direct action
of rivet pintail presenter 145. That is, as rivet pintail presenter
145 is elevated by the action of presentation rack 167, two rivet
pintail presenter positioning rods 177, longitudinally extending
through rivet pintail presenter 145, and fitted within rivet
pintail presenter positioning rod recesses 173 within rivet pintail
presenter 145, are also elevated. These rivet pintail presenter
positioning rods 177, prior to rivet pintail presenter 145
elevation, extend into the lowermost portion of two corresponding
rivet body presenter positioning slots 175 within rivet body
presenter 143, and, a short time after rivet pintail presenter 145
begins its upward ascent, courtesy of presentation rack 167, the
rivet pintail presenter positioning rods 177 engage the upper edge
of their corresponding rivet body presenter positioning slots 175,
thus effectuating elevation of rivet body presenter 143 as well.
The rivet pintail presenter positioning rods 177 and rivet body
presenter positioning slots 175 are positioned so that, when the
rivet pintail presenter positioning rods 177 engage the upper edge
of the rivet body presenter positioning slots 175, the presenter
channels are in axial alignment as required for effective rivet
presentation.
[0226] The motivation for the use of the rivet pintail presenter
positioning rods 177 and rivet body presenter positioning slots 175
is twofold. First, for reasons outlined subsequently, it is
desirable to ensure that, when the rivet body presenter and rivet
pintail presenter are lowered (at a later stage in the blind rivet
installation process), the rivet pintail presenter's descent
precede the rivet body presenter's descent. Second, the rivet
pintail presenter positioning rods 177 and rivet body presenter
positioning slots 175 serve to assist the clip-fed rivet delivery
system structural housing 141b and clip-fed rivet delivery system
guide track assembly 171 in securing the position of the rivet body
presenter 143 and rivet pintail presenter 145. Simply put, the
rearmost longitudinal portion of the rivet pintail presenter
positioning rods 177 are fixedly secured within the body of rivet
pintail presenter 145, and the foremost portions of the rivet
pintail presenter positioning rods 177 are loosely, but securely,
fitted with a washer and retention nut so as to assist in securing
the position of the rivet body presenter 143 and rivet pintail
presenter 145.
[0227] From an automation/computerized control standpoint, it is
helpful to note that, as in the case of reciprocation air cylinder
21, the valving associated with the presentation air cylinder 33
has been usefully configured such that air pressure only acts upon
the air cylinder 33 during stroke; that is, once the air cylinder
piston has been stroked to its desired new position, the associated
air valve releases the air pressure on the air cylinder. This
allows the forward reciprocation of nose assembly 43 in stage ten
and stage eleven to depress the rivet pintail presenter 145 and
rivet body presenter 143 without having to overcome additional
resistance from presentation air cylinder 33.
[0228] It is also helpful to note that presentation air cylinder 33
typically strokes to no less than three discrete locations (see,
e.g., stage nine, stage twelve, stage thirteen); therefore, the
presentation air cylinder 33 is configured with no less than three
feedback sensors (e.g., hall sensors) to facilitate the emission of
control signals to the system controller.
[0229] Stage Ten: Rivet Load.
[0230] Turning, now, to FIG. 10, the blind rivet installation
system 1 is shown at stage ten in the blind rivet installation
process; that is, the blind rivet installation tool 5 is shown in
the state experienced after rivet presentation as the nose assembly
initiates loading of the rivet.
[0231] Even a cursory inspection of FIG. 10 reveals that the nose
assembly 43 has now reciprocated/advanced forward such that rivet
3b is now partially loaded within nose assembly 43 (i.e., the
pintail of rivet 3b is now located within nose insert 11) (see also
FIG. 10A). Note, in FIG. 10, that the nose insert 11 has just come
into contact with the ramp 145b (a linear ramp in the embodiment
shown) of rivet pintail presenter 145. Rivet pintail presenter
linear ramp 145b features a channel radius of curvature which is
approximately equal to that at the outer periphery of the
cylindrical section of nose 9.
[0232] Designing rivet pintail presenter ramp 145b in the fashion
described hereinabove ensures that nose 9 smoothly and easily
engages rivet pintail presenter linear ramp 145b, urging it
downward as nose assembly 43 advances during rivet load. As nose
assembly 43 advances, the pintail of rivet 3b enters the jaws 49
and rivet pintail presenter 145 is continuously urged downward,
until, as nose insert 11 approaches head 3b(3) of rivet 3b, rivet
pintail presenter positioning rod 177 engages the lowermost portion
of rivet body presenter positioning slot 175, urging rivet body
presenter 143 downward (see FIG. 8A).
[0233] It is desired for rivet body presenter positioning slot 175
to be of such a length that the rivet body presenter 143 will be
urged downward shortly before rivet head 3b(3) strikes the surface
of rivet body presenter ramp 143b (see FIG. 9A and FIG. 10B). Rivet
body presenter ramp 143b (a linear ramp in the embodiment shown)
has been fashioned to urge rivet body presenter 143 downward if
rivet head 3b(3) should impinge upon rivet body presenter 143
during its forward travel, and it is desired for rivet body
presenter linear ramp 143b to feature a channel radius of curvature
approximately equal to the radius of curvature of rivet head
3b(3).
[0234] Finally, it should be noted that, as nose assembly 43
advanced, the paw stop actuators 151 were engaged, and these, in
turn, actuated the paw stop assemblies 149. However, as discussed
previously, the paw stop assemblies, at this time, harmlessly come
into contact with the rearmost surface of the rivet pintail paws
147. See FIG. 9A as well as the extensive discussion of the paw
stop actuators 151 and paw stop assemblies 149 at stage eight.
[0235] Stage Eleven: Nose Assembly Full Extension.
[0236] Turning, now, to FIG. 11, the blind rivet installation
system 1 is shown at stage eleven in the blind rivet installation
process; that is, the blind rivet installation tool 5 is shown in
the state experienced after rivet loading has occurred and the nose
assembly has been fully forwardly extended and locked into
position. From a rivet installation standpoint, the blind rivet
installation tool 5 status can be aptly described as "rivet ready"
for installation.
[0237] Note, in FIG. 11, that nose assembly 43 is in its
forwardmost position vis-a-vis the blind rivet installation tool 5.
Note as well that nose assembly 43 has been locked into position
via outer collet 45 (note, similarly, the locked position of collet
lock 13). Finally, note the position of rivet 3b: it stands ready
for installation, securely positioned within jaws 49. With a
squeeze of trigger 29, blind rivet installation of rivet 3b (the
successor of rivet 3a) will occur.
[0238] The reader will observe that, at this point in the
installation process, nose assembly 43 has been reciprocated fully
backward and fully forward. This back-and-forth movement of nose
assembly 43 could have the effect of momentarily distracting the
user of the tool from his installation locus, and it could also
constitute a mild safety-related hazard. Thus, it is desirable to
fit the tool with a pointing sleeve, a fixed, cylindrical tube
which encircles nose assembly 43.
[0239] As stated, the pointing sleeve (not shown in the figures) is
a simple cylindrical member which largely encircles the nose
assembly 43 (the lower portion of the cylindrical member comprising
a generally longitudinal, long, wide slot to allow for, among other
things, the operation of the rivet presenters 143, 145 and the paw
stop actuators 151). The user using the tool, and those around him
or her, therefore, cannot inadvertently be struck by the
back-and-forth reciprocation of nose assembly 43 that occurs at the
forward sections of the tool, and the user is further benefited by
having the pointing sleeve as an aid to facilitate the easy visual
positioning of the extremity of the nose assembly 43 near the rivet
hole during reciprocation.
[0240] The pointing sleeve can also be configured so as to serve
the purpose of noise abatement. Specifically, the cylindrical wall
may feature the use of sound-insulating material and the
forwardmost pointing sleeve extremity may be configured to feature
a noise-abating cup/edge which translates forward and seals around
the rivet installation site so as to dampen/muffle the sound
created when pintail break occurs.
[0241] Provision for the pointing sleeve is apparent in the
figures; for example, in FIG. 11, FIG. 11C, and FIG. 11D, a
pointing sleeve counterbore 229, to receive the pointing sleeve, is
shown.
[0242] From an automation/computerized control standpoint, it is
helpful to note that the reciprocation of nose assembly 43 to its
fully forward position is an event which could practically be
evidenced by the feedback signal(s) (e.g., the hall effect signals)
from reciprocation air cylinder 21. At this point in time, as
described above, the system controller would send a control signal
to collet lock air cylinder 61 to effectuate locking of outer
collet 45.
[0243] Stage Twelve: Stroke Presenter Down.
[0244] Turning, now, to FIG. 12, the blind rivet installation
system 1 is shown at stage twelve in the blind rivet installation
process; that is, the blind rivet installation tool 5 is shown in
the state experienced after the nose assembly has been fully
extended forward and the rivet pintail presenter 145 has been
stroked downward, advancing a series of rivets for eventual
presentation, as more fully described hereinbelow.
[0245] FIG. 12B depicts several components of the clip fed rivet
delivery system 7. Presentation air cylinder 33 has advanced
turnbuckle 35, and, thereby, presentation connecting rod 37, to the
fully forward position. Presentation connecting rod 37, by means of
dowel pin 71, has rotated large sprocket hub 159 counterclockwise
(as viewed in FIG. 12B from the perspective of a viewer facing in
the positive z-direction) so as to lower presentation rack 167 and,
thereby, rivet pintail presenter 145.
[0246] Note, in FIG. 12B, the presence of a series of rivets
following a generally u-shaped path leading to presentation. The
next rivet to be presented is rivet 3c. Although additional details
regarding how this series of rivets is secured within the clip fed
rivet delivery system 7 are provided hereinbelow, FIG. 12B does
provide insight regarding how this series of rivets is advanced
along its path.
[0247] Briefly, rivet drive belt 209, which translates in a
clockwise direction about entry pulley 205 (clockwise about entry
pulley 205 as shown in FIG. 12B and as viewed looking in the
positive x-direction), rotates about entry pulley 205 and
simultaneously translates the rivets, the rivets rolling alongside
rivet body side track plate island 215, so as to advance the rivets
along their desired path.
[0248] Turning, now, to FIG. 12A, a different view of many of the
same components presented in FIG. 12B is presented. An inspection
of FIG. 12A reveals that, as presentation connecting rod 37 is
urged forward, and large sprocket hub 159 is rotated clockwise (as
viewed in FIG. 12A when facing the negative z-direction),
presentation chain 161 drives small presentation sprocket 163
which, in turn, drives presentation gear 165 so as to rotate in a
similarly clockwise direction. The rotation of presentation gear
165 drives presentation rack 167 downward, and this, in turn,
drives rivet pintail presenter 145 downward as well.
[0249] Attached to rivet pintail presenter 145 is belt rack 179;
it, too, is driven downward. As belt rack 179 is translated
downward, it induces the counterclockwise rotation of rack gear
181.
[0250] Rack gear 181 contains one-way bearing 183 and hex drive
shaft 185. Hex drive shaft 185 not only serves as a shaft for rack
gear 181, in addition, it serves as a shaft for hex gear 187.
One-way bearing 183 and hex drive shaft 185 cooperate to ensure
that, as belt rack 179 translates downward and rack gear 181
rotates counterclockwise, hex gear 187 is rotated counterclockwise
as well. However, importantly, when belt rack 179 is translated
upwards, inducing a clockwise rotation in rack gear 181, hex gear
187 does not rotate; rather, hex gear 187 stands idle.
[0251] As stated previously, FIG. 12, FIG. 12A, and FIG. 12B all
depict the status of the blind rivet installation system 1 and clip
fed rivet delivery system 7 at stage twelve, at the conclusion of
the downward stroke of rivet pintail presenter 145. As rivet
pintail presenter 145 and belt rack 179 stroke downward, the
counterclockwise rotation of rack year 181 and hex gear 187 induces
the clockwise rotation of idler gear 189. The clockwise rotation of
idler gear 189 induces the clockwise rotation of large belt drive
sprocket 191, and the resulting translation of belt drive chain 193
results in a clockwise rotation of small belt drive sprocket 195.
As small belt drive sprocket 195 rotates clockwise, belt drive
shaft 197 is induced into clockwise rotation as well; this
clockwise rotation rotates belt drive pulley 199, resulting in
one-way translation of rivet drive belt 209 throughout the clip fed
rivet delivery system 7.
[0252] An inspection of FIG. 12A and FIG. 12B reveals the following
path of rivet drive belt 209: a locus of rivet drive belt 209
leaves belt drive pulley 199, translates toward and eventually
rotates about first idler pulley 201, translates toward and rotates
about second idler pulley 203, translates toward and rotates about
entry pulley 205, translates toward and rotates about third idler
pulley 207, and then return translates to belt drive pulley 199. It
will also be appreciated that the translation of rivet drive belt
209 urges the entire series of rivets towards the uppermost portion
of clip fed rivet delivery system 7 to facilitate their one-by-one
presentation by means of rivet pintail presenter 145 and rivet body
presenter 143.
[0253] Finally, it will be appreciated that belt rack 179, rack
gear 181, hex gear 187, idler gear 189, and large belt drive
sprocket 191 have all been configured so that the downward stroke
of belt rack 179 has been effectively converted into a forward,
driving translation of rivet drive belt 209, while the return
upward stroke of belt rack 179 leaves rivet drive belt 209 idle
(owing to the action of one-way bearing 183 and hex drive shaft
185).
[0254] A careful study of FIG. 12 and FIG. 1F reveals how the
rivets are secured so as to facilitate their fluid march in
succession towards presentation.
[0255] FIG. 1F depicts important components of the clip fed rivet
delivery system 7 absent the clip fed rivet delivery system
structural housing 141. Rivets are loaded in succession into clip
fed rivet delivery system main rivet channel 227. Much, but not
all, of the orienting of the rivets 3 after loading occurs as a
result of the placement of the rivet heads within main rivet
channel 227, which itself comprises two transverse rivet channels,
transverse rivet channel 227a and transverse rivet channel
227b.
[0256] The main rivet channel 227 can be profitably described in
two different ways. One way, as referenced hereinabove, is to
describe it by reference to two opposing transverse rivet channels.
The first transverse rivet channel 227a is formed, in the
embodiment shown herein, from rivet body side track plate island
215, rivet head track plate island 225, and rivet pintail track
plate island 223. These three members cooperate to create
transverse rivet channel 227a which receives a generally
semi-circular portion of the rotating and translating rivet head.
It should be noted that transverse rivet channel 227a could easily
be equivalently constructed of one homogeneous material, rather
than three.
[0257] The second transverse rivet channel 227b is formed, in the
embodiment shown herein, from rivet body side track plate 217,
rivet head track plate 221, and rivet pintail side track plate 219,
and these three members similarly cooperate to create a transverse
rivet channel 227b which receives the opposite generally
semi-circular portion of the rotating and translating rivet head.
It should also be noted that transverse rivet channel 227b could
easily be equivalently constructed of one homogeneous material,
rather than three.
[0258] An alternative way of viewing main rivet channel 227 is to
view it as a path which has been carved out of three track plates,
creating, in effect, three track plate "islands." For example, one
could envision defining rivet body side track plate island 215 as
the "island" that has been created by carving a u-shaped path, main
rivet channel 227, into rivet body side track plate 217. Similarly,
rivet pintail side track plate island 223 may be viewed as the
"island" that has been created by carving main rivet channel 227
into rivet pintail side track plate 219. And rivet head track plate
island 225 may be viewed as the "island" that has been created by
carving main rivet channel 227 into rivet head track plate 221.
[0259] Regardless of semantics, it is clear from FIG. 1F that a
main rivet channel 227, a generally u-shaped path in the embodiment
shown herein (to increase the number of rivets 3 that are housed
within the clip-fed rivet delivery system 7), has been created, and
it is through this channel that the rivets 3 progress in their
march towards presentation. Thus, a primary alignment mechanism by
which the rivets 3 are aligned and simultaneously translated is the
creation of main rivet channel 227, which itself comprises the
opposing generally u-shaped transverse rivet channels 227a and
227b, which utilize the rivet head, and the body and pintail
portions immediately adjacent thereto, for alignment and
translation.
[0260] A close inspection of FIG. 1F reveals that rivet drive belt
209 contacts one generally semi-circular side of the rivets and
translates the rivets along the desired path by rotating/rolling
them along main rivet channel 227. Thus, each individual rivet 3 is
translated by means of the action of the rivet drive belt 209 and
the simultaneous advance of the rivets 3 behind it.
[0261] Because the rivet drive belt 209 is not positioned within
main rivet channel 227, but, rather, is located to one side of it
(i.e., just forward of it in the embodiment shown), it is useful to
position a rivet roll bar guide plate 211 (or some other equivalent
mechanism such as a unitary extension on the rivet body side track
plate island 215 or a balancing belt positioned at an opposite
location vis-a-vis the main rivet channel 227) so that, as the
rivet 3 rolls along main rivet channel 227, it is, throughout most
of its path towards presentation, being gently squeezed between
rivet drive belt 209 on one side and the rivet body side track
plate island 215, rivet pintail side track plate island 223, and
the normally (i.e., oppositely) positioned rivet roll bar guide
plate 211 on the other. The spaced positioning of the roll bar
guide plate 211 must allow for the placement of the rivet body
presenter 143 between it and the rivet body side track plate island
215 and the rivet body side track plate 217.
[0262] As the rivet rolls along, twitter (i.e., movement of the
rivet off of the x-axis, for example, in the direction of the
y-axis) is effectually limited by the action of the two transverse
rivet channels 227a and 227b which secure the rivet, by means of
its head, into position. A rivet guide plate 213 facilitates the
smooth translation of the rivets as they traverse the bottom of the
u-shaped main rivet channel 227.
[0263] Although the clip-fed rivet delivery system 7 described
herein is particularly well suited for what are commonly known in
the industrial and aerospace fastening industries as blind rivets,
the feed mechanisms described will obviously perform their intended
functions with any substantially axis-symmetric part containing an
enlarged axis-symmetric cross-section.
[0264] Stage Thirteen: Presenter Prior to Rivet Capture.
[0265] Turning, now, to FIG. 13, the blind rivet installation
system 1 is shown at stage thirteen in the blind rivet installation
process; that is, the blind rivet installation tool 5 is shown in
the state experienced just prior to rivet capture.
[0266] At this moment in time, presentation air cylinder 33 (not
shown in FIG. 13) has retracted turnbuckle 35, and, thereby,
presentation connecting rod 37, to a substantially rearward
position. Presentation connecting rod 37, by means of dowel pin 71,
has rotated large sprocket hub 159 clockwise (as viewed in FIG. 13
from the perspective of a viewer facing in the positive
z-direction) so as to raise presentation rack 167 and, thereby,
rivet pintail presenter 145, as described hereinabove.
[0267] The next rivet in succession, rivet 3c, is shown in its
position in stage thirteen just prior to capture. When the
presentation connecting rod 37 is further retracted a short
distance, the rivet 3c will be further elevated by rivet body
presenter 143 (not shown in FIG. 13) and rivet pintail presenter
145.
[0268] It should also be noted that, during this stage, when
presentation connecting rod 37 translates rearward, rivet drive
belt 209 does not translate due to the configuration of rack gear
181, one-way bearing 183, and hex drive shaft 185, as described in
the discussion of stage twelve.
[0269] As stated, when the presentation connecting rod 37 is
further retracted a short distance, the rivet 3c will be further
elevated by rivet body presenter 143 (not shown in FIG. 13) and
rivet pintail presenter 145; however, its upward ascent will be
limited by the paws 147 which are secured in position by the paw
stops 149 (not shown in FIG. 13).
[0270] When the rivet 3c is driven into the paws 147, it will be
fully "captured" within rivet body presenter 143 and rivet pintail
presenter 145. Specifically, captured rivet 3c will be fully seated
and snapped into rivet body presenter channel 143a and rivet
pintail presenter channel 145a (the rivet presenter channels being
depicted within both FIG. 9A and FIG. 13).
[0271] At this point, the rivet 3c is fully secured for
presentation, as described in the discussion of stage eight and
stage nine.
[0272] Fastener Delivery Systems.
[0273] The reader will note that much of the discussion contained
within this specification is devoted to a blind rivet installation
system 1 for the blind installation of rivets 3, the specific blind
rivet installation system 1 featuring a blind rivet installation
tool 5 equipped with a clip-fed rivet delivery system 7.
[0274] Although a clip-fed rivet delivery system is an effective,
portable method of delivering rivets 3 to the blind rivet
installation tool 5, there are occasions in which a higher-volume
rivet delivery system is desired.
[0275] A useful blowline-fed rivet delivery system comprises a bulk
supply receptacle which stores a large volume of rivets for
high-volume delivery to the blind rivet installation tool 5.
[0276] The bulk supply receptacle comprises a bin, a separator, a
transfer device, an orienter, a queueing transfer device, and
either a gate or an inspection/sorting device. The bin houses a
large supply of rivets for high-volume delivery to the blind rivet
installation tool 5. Several alternative methods may be employed in
the design of the separator; a useful approach employs an elevating
paddlewheel which scoops a modicum of rivets from the bin, elevates
them, and transfers them to a transfer device.
[0277] The transfer device may also utilize a variety of designs.
An effective transfer device employs a set of inclined, parallel,
oppositely-spinning bars at the base of a trough. The spinning of
the bars, and their inclined orientation, induces the sliding
movement of vertically oriented rivets to the orienter.
[0278] The orienter separates the vertically oriented rivets in
such a fashion that those that are properly oriented for
introduction into the queueing transfer device and the
inspection/sorting device are passed to those devices, while those
that are oppositely oriented are returned to the bin. The orienter
may profitably employ a number of design concepts; one useful
approach is to employ a T-shaped rivet channel which separates the
vertically oriented rivets based upon the relative difference
between the rivet pintail diameter and rivet body diameter.
[0279] Properly oriented rivets exiting the orienter enter the
queueing transfer device which employs a drive belt, track plates,
and roll bars (in a fashion similar to that described in stage
twelve) to transfer the rivets, in individual succession, along a
path towards the gate or inspection/sorting device. Upon command
from the system controller to pass a rivet to the tool, the gate or
the inspection/sorting device (the latter culling rivets which do
not meet pre-defined criteria) passes a rivet to the blowline.
[0280] The blowline passes individual rivets at high speed from the
bulk receptacle to the blowline-fed rivet delivery system connected
the blind rivet installation tool 5. Importantly, the blowline-fed
rivet delivery system is inter-connected to the blind rivet
installation tool 5 utilizing the same docking connections that are
utilized by the clip-fed rivet delivery system 7 described
hereinabove. Similarly, two blowline portals 231, one of which is
shown in FIG. 9A, linearize the final section of blowline entering
the blind rivet installation tool 5 and secure the position of the
blowline directly (i.e., closely) below the hydraulic cylinder and
along the longitudinal axis of the blind rivet installation tool
5.
[0281] The blowline-fed rivet delivery system comprises a rivet
catcher assembly which captures arriving rivets for action by a
rivet presentation assembly. The rivet presentation assembly may
utilize a rivet pintail presenter, rivet body presenter, and paws
in a manner similar to that depicted in stage eight, stage nine,
and stage thirteen.
[0282] A Blowline--Feed Delivery System "Bulk Feeder"
[0283] With reference now to the drawings, and in particular with
reference to FIG. 201F, a bulk feeder for use in conjunction with a
fastener installation system is shown. Reference characters are not
employed in the instant figures because, given reader familiarity
with the fastener installation system provisional patent
application and the technologies described therein, they are
unnecessary.
[0284] Shown in FIG. 201F is the feeder and the escapement system.
Looking at the feeder shown here are rivets in random orientation
laying in the hopper. The reader will observe some rivets that have
slid out of the hopper into the paddlewheel feed system. Also, the
reader will observe that a number of rivets are being transported
in the queue track. Further, a few rivets are in the escapement
system.
[0285] With reference now to FIG. 202F, an opposite (or rear view)
of the feeder assembly is shown. A motor is mounted to two
oppositely oriented z-rails. This motor couples to the paddlewheel
(not shown) in order to rotate the paddlewheel and thereby propel
or lift the rivets to an elevated location where they roll down
into a set of spinning transport bars. The motor to the far right
is coupled to the spinning transport bars via a rubber belt.
[0286] With reference now to FIG. 203F, a rear view is again
presented, and, in this view, the paddlewheel rear guide plate is
removed for clarity. Here one observes rivets laying against the
paddles. This view from the rear depicts the wheel rotating
clockwise. It should be understood that the paddlewheel can be
driven in either direction (clockwise or counter-clockwise)
depending on the parts that are being fed. The preferred embodiment
here and for many applications is counter-clockwise as viewed from
the rear (and as shown in FIG. 204F and FIG. 205F). This elevates
the parts and then allows them to roll off onto the spinning bars
with a minimum of freefall or drop. By minimizing the freefall
and/or drop, the resulting impact on the parts is minimized. It is
also possible to construct the outer surface of the main
paddlewheel cylinder as a conic section, so that the rivets can be
elevated by the paddles to the uppermost position on the
paddlewheel so as to slide down the conic surface and through a
port in the front or rear guide plate on to the spinning bars (or
on to a spinning bar trough feed section).
[0287] With reference now to FIG. 204F and FIG. 205F, in these
views, one can observe the rivets coming through the front side
paddlewheel guide plate from the hopper on the far side. As the
paddlewheel rotates, it pushes the rivets along the paddlewheel
trough. The trough stops and has a slide where the rivets exit onto
a pair of oppositely spinning bars.
[0288] The spinning bars are spaced to allow the rivets to hang
down through or between the bars. The spinning bars are also
inclined or angled downward from the horizontal plane. The angle
should be between 5-15 degrees depending on the parts that are
being fed.
[0289] The combination of oppositely spinning bars and the inclined
smooth surface of the spinning bars acts to propel the parts down
the slope.
[0290] In FIG. 205F, the concentric circles located just below the
motor are representations of spur gears. Gears are utilized here to
create oppositely spinning bars. The bars are attached to these
gears and go through bushings held in the mounting bracket.
[0291] With reference now to FIG. 206F, in this view, rivets are
shown in various orientations after they have slid down out of the
paddlewheel into the spinning bars. Here, some of the rivets are
right-side-up (i.e., in a useful orientation for convenient and
effective blowline feeding) and others are up-side-down (i.e., in a
reverse orientation) with respect to each other.
[0292] With reference now to FIG. 207F, in this view, the rivets
are traveling down the inclined spinning bars and entering a
sorting block. The sorting block allows upside down rivets to
travel straight forward and through the sorting block and
eventually falling back into the hopper.
[0293] Rivets which are right-side-up are diverted ninety degrees
and into a queue track which propels the rivets to an escapement
device.
[0294] With reference now to FIG. 208F, another front view of the
feeder is depicted. Here, the reader can observe the elevational
views of several functions.
[0295] Note the hopper and the rivets contained within it. The
paddlewheel lifts the rivets to the height required to enter the
spinning bars. The spinning bars ramp down to the sorting block.
Upside-down rivets fall from the sorting block back down into the
hopper.
[0296] With reference now to FIG. 209F, in this view, several
properly oriented rivets are being transported down a queue track
towards the escapement system. Just inside the wall where the
escapement is mounted, the reader will observe a motor. This motor
drives a belt which propels the rivets down the queue track
(utilizing a rivet roll bar guide plate and guide slot-based track,
albeit with a flat belt, in a manner similar to that described in
the fastener installation system provisional patent
application).
[0297] The Blowline--Feed Delivery System Bulk Feeder
Escapement
[0298] With reference now to FIG. 210F, in this view, rivets are
observed entering an index wheel with specially cut slots
configured to accept the rivets. Here, there is a rivet at each of
three locations and one rivet that has been scrapped out of the
index wheel and is shown falling down into a funnel-shaped
receiver.
[0299] Also shown is a sensor block/bridge that spans over and
around the path of the rivet. On both sides of the bridge infrared
or other sensors are located so that, as the rivet is rotated along
its path, this infrared beam is blocked (or other monitoring sensor
triggered). This, in turn, signals the controller and is used to
stop the index wheel at the correct location to accept a new rivet
from the queue track (note that the hole halfway up the bridge is
where the sensors are located).
[0300] Note that this escapement system uses no conventional gating
system. Instead, the rivet is scraped from the index wheel and then
the rivet falls into the funnel.
[0301] After the rivet falls into the funnel, the cover is slid
over the funnel which, via a face seal, seals the blowline feed
chamber and tube. Now, compressed air is introduced at a high
volume flow rate which then propels the rivet down the blowline
feed tube.
[0302] With reference now to FIG. 211F, in this view, the funnel
cover is shown in its closed position, ready to blow a rivet down
the feed tube.
[0303] A Blowline--Feed Delivery System "Catcher"
[0304] With reference now to FIG. 201C, in this view, the fastener
installation system is shown with the nose assembly in the
retracted position. The catcher assembly is attached to the gear
drive housing. The catcher also has a safety cover which surrounds
the catcher assembly.
[0305] With reference now to FIG. 202C, in this view, the tool and
catcher assembly are shown alone with the paws. The catcher housing
and cover are not shown for clarity. Also shown are the two
presenters (i.e., the rivet pintail presenter and the rivet body
side presenter).
[0306] With reference now to FIG. 203C, in this view, the catcher
body is not shown in order to show the two presenters, the location
gates, the gate keepers, the impact piston, the rivet, the spring
cover, the blowline feed tube, the rack gear, and the rack gear
drive assembly. The rivet is shown as it exits the blowline feed
tube and is about to impact the location gates. Not shown are small
coil compression springs that close the location gates.
[0307] With reference now to FIG. 204C, in this view, the rivet is
shown as it is entering the rear of the tool. The rivet is actually
being transported through a plastic (e.g., nylon, teflon, etc.)
tube and is propelled via compressed air. As the rivet approaches
the tool, the plastic tube enters a closely fitted metallic tube.
The plastic tube is thereby held in a straight configuration. This
yields a straight line path for the rivet. This helps to ensure
that the rivet travels in a predictable path.
[0308] Also shown in this view is a compression spring that reacts
between the impact piston and the spring cover. The spring here
acts to absorb the impact of the rivet. The rivet is actually
stopped by this impact piston and spring combination.
[0309] With reference now to FIG. 205C and FIG. 206C, two different
views that show the rivet as it is entering the catcher body are
shown (catcher body not shown). It is noted that the rivet catcher
mechanisms described herein are aligned with the blowline feed tube
and the presenter assembly; however, it would be possible to enjoy
further savings of cycle time by shifting the location of the
catcher assembly and blowline feed tube to one side so that a
shuttle mechanism can transport the most recently arrived rivet
upon demand to the presenter assembly while the blowline feed tube
delivers another rivet to the catcher.
[0310] With reference now to FIG. 207C, in this view, the rivet is
shown just after it clears the location gates. Here, the gates have
been opened by the head of the rivet and, after the head clears the
gates, the gates are closed via compression springs. The gates in
their most-closed position are spaced such that the pintail is a
loose fit. The pintail can move unobstructed in the vertical
direction.
[0311] Also shown is the impact piston and compression spring just
as the rivet impacts the impact piston. Here, the impact piston and
spring act to decelerate the rivet and then to move the rivet into
a reproducible location. The rivet is located in the longitudinal
direction along the x-axis between the piston and the location
gates. The head of the rivet is larger than the location gate gap
thereby stopping the travel of the rivet as it bounces back off the
impact piston.
[0312] Both the gates and the impact piston are fitted with a high
hardness urethane (or other similarly functional) bumper material.
As shown, the gates appear in two pieces and are comprised of a
light weight aluminum rectangular door or gate and attached to its
impact side (i.e., its rearmost face) is a high hardness urethane
bumper.
[0313] The location gates have a purpose in addition to final
containment of the rivet. They also act to slow the rivet as it
comes flying through the gates. At this point, the rivet might
easily be traveling at a speed of fifty to one hundred miles per
hour. The large variability in speed is due to several factors
including the length of the blowline feed line. In twenty-five-foot
blowline feed tubes, the speed can reach fifty to sixty-five miles
per hour. The rivet is constantly accelerating, and, therefore, as
the tube gets longer, the rivet's speed is increasing. Naturally,
there is a limit to the rivet's velocity, and some control is
attainable by controlling the air volume, velocity and
pressure.
[0314] As stated, the impact piston also is equipped with a high
hardness urethane on its impact surface. This protects the piston
and rivet from damage as the rivet strikes the impact piston. As
the rivet flies into place, its path crosses through or in between
a set of infrared sensors. One sensor is an emitter, and the other
is a receiver. As the rivet blocks this beam an electrical signal
is interrupted, thereby signaling the tool controller that a rivet
has been delivered. Once the rivet comes to rest, it is ready to be
captured by the presenters.
[0315] With reference now to FIG. 208C, in this view, the
presenters have moved up through the catcher body and delivered the
rivet up to the paw position (whether by means of the rack-and-gear
system described in the fastener installation system provisional
patent application or by a vertically mounted air cylinder
positioned within the gear drive housing and coupled to the
presenters). This would be expected to occur when the nose is in a
somewhat extended position (note: in this figure, the nose is
retracted solely for clarity).
[0316] With the nose in the extended position, the presenters and
paws can be positioned such that no paw stop system is
required.
[0317] It has been discovered that the nose can be used to stop the
rivet and create the oppositional force required to snap the rivet
body into the body side presenter. After this is accomplished, the
presentation air cylinder is vented of its air pressure, allowing
the entire mechanical system to relax. This basically yields the
rivet captured in the body side presenter and the rivet flange
located just below the nose. The paws now act as guides to
facilitate the capture of the rivet in the body side presenter.
[0318] With reference now to FIG. 209C, in this view, the
presenters and rivet are shown in the fully extended load position.
Now, the axis of the rivet and the axis of the nose are aligned.
The nose may move forward and capture the rivet.
[0319] With reference now to FIG. 210C, in this view, the nose is
shown in the process of moving forward and capturing the rivet
(engaging the pintail presenter in the same manner as described in
the fastener installation system provisional patent
application).
[0320] Modularized Embodiments of the Shock Mitigation
Functionality
[0321] With reference now to FIG. 201S1 and FIG. 201S2, there are
depicted alternative methods of construction of a rivet tool
utilizing the shock mitigation functionality previously fully
described in the fastener installation system provisional patent
application. Many of the components that comprise this system are
either identical to (or very similar to) the system described in
the fastener installation system provisional patent
application.
[0322] A cursory review of the instant embodiment reveals that this
configuration does not have the components necessary for
reciprocation of the nose rearward through the tool. Therefore, the
necessity for an inner collet assembly is eliminated. The reader of
the fastener installation system provisional patent application
will recall, for example, that the inner collet 93 described in
that application was utilized to impart the rearward force on the
pull rod 55 in order to install a rivet 3.
[0323] In the instant application, a pull rod nut member 357 is
utilized to create a similar action. In FIG. 201S1b, pull rod nut
357 is attached to pull rod 355. This assembly could also be
produced as one part whereby a substantial shoulder and face are
created in order to transfer the load from the piston rearward face
to the pull rod 355. In this embodiment, the pull rod nut 357 is
constructed such that its forward face 363 will mate to the
rearward face 365 of piston 391.
[0324] As piston 391 is translated rearward, due to the
introduction of hydraulic fluid, these two faces will translate
rearward causing the pull rod 355 to move rearward also. As pull
rod 355 translates rearward, the rivet installation process
proceeds.
[0325] When the rivet installation process completes, and the
pintail or pull mandrell breaks, the pull rod assembly 373
accelerates rearward and it is decelerated by the dampening spring
359.
[0326] In FIG. 201S2b, the piston 391 is shown in its rearward
position illustrating the translation after introduction of
hydraulic fluid. The pull rod 355 and pull rod nut 357 are shown in
a rearward position illustrating the relative movement of these
components to the piston 391. Notice the piston rearward face 365
and the pull rod nut forward face 363 are substantially displaced
from one another (illustrating the same de-coupling action
described in the fastener installation system provisional patent
application).
[0327] This displacement is achieved through the compression of
dampening spring 359. After pintail break, the pull rod assembly
373 accelerates rearward compressing dampening spring 359. This
compression of dampening spring 359 is the primary shock absorption
mechanism.
[0328] Also note the pull rod outer seal 357. This seal can also be
utilized to create dampening through the work performed by rapidly
compressing the air trapped between the nose 309 and the pull rod
355.
[0329] In FIG. 201S2a, the displacement of the pull rod assembly
373 is also apparent. Comparing this figure to FIG. 201S1a, one
observes that components 347, 349, 357, 355, 351, and 353 have all
translated rearward. The translation amplitude is the sum of the
translation of the piston 391, as shown in FIG. 201S2b, and the
translation of the pull rod assembly 373 after pintail break
enabled by compression of dampening spring 359.
[0330] FIG. 201S1b and FIG. 201S2b illustrate a piston bushing 337.
This component is utilized to create a guide for the pull rod. This
bushing may be constructed of a hard impact-resistant plastic with
a lubrication additive. The bushing serves to guide the pull rod
during the rapid acceleration-deceleration cycle. A plastic would
be an example of a highly advantageous, even preferred, material,
because it enables the design to meet weight requirements (note:
brass, bronze and similar materials would likely be effectual as
well).
[0331] With reference now to FIG. 202S1 and FIG. 202S2, there are
depicted designs of a shock absorbing rivet installation system
designed such that the system could easily be adapted to fit on (or
attach to) almost all conventional rivet tools. In the trade, such
an assembly might be expected to be referred to as a "modular nose
assembly." These designs also utilize the shock mitigation
functionality previously fully described in the fastener
installation system provisional patent application.
[0332] Hydraulic cylinder 417 and piston 491 are illustrated here
in a workmanlike configuration. Whether the piston and hydraulic
cylinder are a part of a pneudraulic or hydraulic-type tool is of
little consequence. Further, the piston shown is illustrated with a
typical half-shell coupling arrangement. The piston could be
configured with threads for the coupling action.
[0333] FIG. 202S1 is a snapshot at the beginning of rivet
installation. FIG. 202S2 is a snapshot after the rivet installation
process is complete and pintail break has occurred.
[0334] In this design, the de-coupling action occurs between the
forward conical face 447(1) of jaw collet 447 and the inner conical
face 455(1) of pull rod/tube 455. The dampening spring 459 acts
between the rearward face 447(2) of jaw collet 447 and the front
face 491(1) of piston 491.
[0335] After pintail break, the pull rod assembly 473 comprised of
447, 449, 451, 453, 455, and 443 all accelerate rearward
compressing dampening spring 459.
[0336] Notice that the spring keeper component 443 has been
threadedly attached where, in the original fastener installation
system provisional patent application, the original pull rod 55
coupled to the to the rear jaw collet 47. The pull rod also acted
as a spring seat for the collet spring. In this design, the pull
rod/tube 455 acts on the front outside conical surface of jaw
collet 447.
[0337] In order to facilitate the proper jaw action (opening and
closing on the pintail), the jaw spring is seated in this spring
seat which is threadedly attached to the jaw collet 447.
[0338] Notice, as well, that the spring follower is extended all
the way rearward and substantially into the piston 491.
[0339] Many, if not most, rivet installation tools are "rearward
ejection"-based tools with regard to the ejection of pintails. In
such designs, a path is required through the piston. Here, the
piston would have a through-hole. A "bounded pathway" is created
with the spring follower. The astute reader will note that the
spring follower is a part of the pull rod assembly 473, and so it
accelerate-decelerates with this assembly during the
rearward/forward action.
[0340] Based upon the foregoing, the process of rivet installation
utilizing such a shock mitigation modular nose assembly becomes
apparent.
[0341] Piston 491 translates rearward with respect to hydraulic
cylinder 417 after hydraulic fluid is introduced. Piston 491 pulls
pull rod/tube 455 via the clamshell coupling 445.
[0342] Pull rod/tube conical face 455(1) pushes on jaw collet
conical face 447(1) creating the translation required to install a
rivet.
[0343] After pintail break has occurred, pull rod assembly 473
accelerates rearward compressing dampening spring 459. After
deceleration completes, the dampening spring returns the pull rod
assembly 473 forward until faces 447(1) and 455(1) mate.
[0344] A Useful "Hydraulic Circuit" to Improve Cycle Time.
[0345] The attentive reader will appreciate that an important
design objective is to reduce, whenever possible and convenient,
the total cycle time associated with the thirteen-stage process of
fastener/rivet installation. In the discussion of stage five (inner
collet re-opening) supra, for example, there was extensive
discussion regarding using air to pressurize the rearward cavity
which aided in the return of the piston. It may not have been
obvious to the inattentive reader that, as the hydraulic piston is
being urged forward, fluid is being pushed backward through the
hydraulic line and the diverter valve back at the pump unit.
[0346] In the application where these systems are likely to be
employed, a substantial distance between the hydraulic unit and the
tool may be desired (generally and easily exceeding twenty-five to
fifty feet or more). This length of hydraulic line can create a
substantial resistance when one wants to push the hydraulic fluid
back to the unit in a short period of time. In the configuration
described particularly at stages four through seven, air pressure
is used to displace that twenty-five foot oil column. The reader
will appreciate that the time required to effectuate such a
displacement is substantial.
[0347] An improved method employs a hydraulic "vent circuit." See
FIG. 301. Here, a vent line is installed where oil may be exhausted
and later returned to the tank or reservoir.
[0348] This is accomplished by installing a mechanically operating
valve (e.g., a spring-operated valve) in the hydraulic circuit
coincident with the tool. This valve closes when high-flow
hydraulics act upon it, thus enabling the tool to build pressure
and do the work required to install the rivet.
[0349] After pin break, and after the hydraulic diverter valve is
released to allow the return of fluid back to the tank, this valve
opens due to the reduction of fluid flow. Next in the cycle, air is
introduced into the rearward cavity of the tool via a pneumatic
valve (in FIG. 301, this circuit it is pneumatic valve 501). This
pressurization of the rearward cavity causes the piston to move and
thus eject hydraulic fluid back through the hydraulic line. At this
point, the fluid has two paths for travel. The first is the path
from whence it came (back down the twenty-five foot line, through
the diverter valve, and into the tank). The second is the path
through the new bleed valve. Here, the valve is configured to allow
a flow rate of fluid that is desired to accomplish expedient piston
return, and this fluid vents by and through a check valve and into
a substantially empty return/drain line.
[0350] The check valve is a one way valve that allows almost
unrestricted flow of fluid in one direction, but does not allow
flow in the opposite direction. Here, the check valve allows a
pressurization of the drain line which acts to propel the vented
fluid through the line to the tank/reservoir. The tank/reservoir is
vented to atmosphere through a filter/breather cap (not shown).
[0351] Thus, in summary, through the employment of such a hydraulic
vent circuit, a vent chamber is created into which fluid is
exhausted during the piston return cycle. This chamber's proximity
to the tool is substantial in that now only inches or millimeters
of fluid (rather than many feet) are being displaced, thus greatly
minimizing the work required to return the piston.
[0352] It has been observed in testing that the use of such a
circuit can reduce the time associated with piston return by an
order of magnitude or more (experimentation has demonstrated
reductions of from approximately four to six seconds to
approximately two-tenths to three-tenths of a second).
[0353] The check valve may not be necessary due to the fact that
both the fluid and air should take the path-of least resistance.
However, use of a check valve minimizes the possibility of an
introduction of air into the hydraulic cylinder. Such an
introduction would not be catastrophic, but it would potentially
result in a dampening and/or reduction of the cycle time in the
installation phase of the cycle.
[0354] Although much attention is given to cycle time in the design
of cyclic automated tools, there are other benefits to the design
and use of the hydraulic vent circuit. For example, the circuit
also provides a cooling mechanism to the system. Because the
venting occurs during each cycle, there is a circulation of
hydraulic fluid. It is known that single-hose hydraulic systems
using air-return or spring-return get hot if they are used in rapid
cycle situations for extended periods of time. This is due to the
friction generated in the oil as it is pressurized. If there is no
circulation of the oil, then the fluid's temperature increases,
and, over time, the increase can be substantial. The circulatory
system described allows small amounts of oil to be circulated
during each cycle, thus contributing to a moderation of system
temperature.
[0355] Another benefit of the circuit is apparent. The circulation
of the hydraulic fluid, which occurs with each cycle, also helps to
keep the system free of air in the hydraulics. Each time the
hydraulic diverter valve is actuated, a small amount of hydraulic
fluid is circulated through the circuit and out the high flow
closed/medium flow open valve. This action works to rid the
hydraulic system of trapped air. Furthermore, when a new tool is
connected to the system, air is often introduced, and this usually
needs to be bled off through convoluted procedures. With the
hydraulic vent circuit, new or replacement tools can be attached to
the system, and several actuations performed on the diverter valve,
resulting in a substantially air-free hydraulic system.
[0356] An Alternative "Queue Track" Design.
[0357] Another embodiment for the production of a queue of
correctly oriented rivets has been developed.
[0358] In this design, in place of the queue track system depicted
in FIG. 209F which employs a belt, motor, and a roll bar guide
plate, a set of rails, which are inclined from the horizontal
plane, is employed. These two rails are angled downward between
five and ten degrees and are separated to create a free sliding fit
to the rivet body. The rivet hangs between the two guide rails by
the rivet head.
[0359] The guide rails are constructed of a slick material, such as
Delrin, Teflon,.RTM. or a metallic material which has been coated
with a friction-reducing material.
[0360] To further aid the smooth translation of rivets down the
tracks to the escaping device, a series of very small air streams
is employed. This is accomplished by using the rails as manifolds,
whereby holes are constructed longitudinally through the rails
creating a reservoir or accumulator. Then, small holes are
introduced at acute angles to the longitudinal axis and
intersecting the reservoir cavity. These holes are spaced and
placed such that air streams exit the rails and impinge on the
rivet bodies just below the rivet heads.
[0361] With the reservoir or accumulator effect, it is possible to
use small flow rates of air and still the velocity of the air
exiting the rails throughout its length is normalized. This system
is different from other inclined rail systems in that there is
frequently no need to employ hold-down rails or top-guide rails.
Inclined feed rail systems are not uncommonly inclined at an angle
of fifteen degrees or more to the horizontal plane (in fact, it is
not uncommon to see thirty to forty-five degree tracks). These
systems typically employ a hold-down rail to stop the parts being
fed from spilling out. The hold-down rails add another surface
which will both impart friction and, importantly, create a
situation in which nesting or sticking often occurs.
[0362] Furthermore, in the instance of manipulation of the head of
a rivet, in conventional systems, a shingling effect is observed.
When this occurs, the parts stick and a jam in the feed system is
developed due to one rivet head riding up slightly upon an adjacent
rivet. Through this displacement, the gap established from the feed
rail top surface to the hold down rails is closed, and, in effect,
the resulting shingling creates a braking action (often resulting
in jams).
[0363] The feed industry has proposed a variety of solutions to
this problem. All feature various disadvantages.
[0364] The inclined rail system described herein does not require
the use of hold-down rails. Therefore, as shingling occurs, no
braking or added friction is produced. The air streams, or jets,
are minimal since they only are required to break the static
friction between the head and the rail. This factor is of practical
import for two reasons. First, the use of compressed air is not
without cost to the end-user. Second, often times, in industrial
environments, compressed air is used to such a degree that it
becomes an environmental issue (i.e., management of noise levels in
the plant). By minimizing the amount of air used in a feed system,
important economies are realized. And by eliminating the hold-down
rails, another common variable contributing to rivet jams is
eliminated, thus increasing overall system throughput and
reliability.
[0365] A "Catcher" Improvement.
[0366] A modified embodiment of the catcher system, targeting a
reduction in total cycle time and the elimination of
throughput-reducing variables, involves the deployment of not one,
but two, rivets in the blow-line feed tube at certain times.
[0367] Starting at the feeder, a rivet is dropped into the conical
shaped receiver, and the cover is closed creating a seal via the
face seal. Also, at this time, another rivet is at the opposite end
of the feed tube adjacent the presenter. Next in sequence, with the
presenters in the down (or, open) position, air would be introduced
to the blow-feed line back at the receiver.
[0368] Now both rivets move. It is most likely the case that the
rivet at the receiver, and closest to the air supply, experiences
the greatest acceleration. The rivet adjacent to the presenter will
be propelled immediately into position, due to the transmission of
air pressure ahead of the oncoming rivet.
[0369] The rivet adjacent the presenter only has to move a few
inches in order to be in position; therefore, it will likely not be
able to accelerate to a significant speed. This is important, in
that, due to this greatly reduced speed, it may be possible to
eliminate the position gates, or at least use a simplified set of
flexible tabs, to ensure that the rivet head is in the correct,
final position. Also, the impact piston may well be eliminated and
replaced with a simple bumper.
[0370] Once the rivet has been propelled into position, an infrared
(IR) emitter and receiver signaling unit will be blocked. This
signal change will invite the controller to sequence the presenters
up. As the presenter moves upward, or shortly after it has reached
the paws, the second rivet would impact the presenter rearward
face. This face is fitted with an impact-absorbing compound. The
impact will naturally result in the rivet bouncing backward (or,
rearward) away from the presenter. In order to re-position the
rivet to a position adjacent the presenter, the air flow may
desirably be left on for a short duration. It is possible that
another set of IR emitter receivers could usefully be employed to
verify the arrival of the second rivet.
[0371] This alternate catcher embodiment is useful in several ways.
First, due to the reduced length of travel, a rivet will reach
proper position for presentation faster. This will allow for a
reduction in the over-all cycle time. Second, the rivet
presentation assembly (or cavity) will be simplified by the
elimination of the impact piston and further by the elimination of
the spring-loaded position gates (or the simplification of the
gates into flexible tabs). These simplifications have the potential
to yield an inherent increase the reliability of the system due to
a reduction in operating variables.
[0372] Also, the stopping of a rivet currently in transport mode
will be more controlled. This better control is achieved since the
rivet will be in an enclosed tube section. The blow-feed tube, as
it abuts the catcher and presenter assembly, is largely a
completely enclosed tubular section. Therefore, as the rivet
impacts the presenter, it has nowhere to recoil but slightly
backwards down the tube. This confinement of the rivet at impact
has the potential to help avert the jams that can occur when there
are open passages for the bouncing rivet to be deflected into or
against. This elimination/reduction of dynamic variables has the
real potential to result in an important increase in overall system
reliability. And, finally, through these improvements, the cost of
construction and maintenance may well be reduced.
[0373] A Threaded Insert Installation System.
[0374] The astute reader will find that another useful embodiment
can be produced that will automate the installation of threaded
inserts. Threaded inserts are produced in a multitude of shapes and
materials. Generally, they are employed to create a nut member on a
piece of sheet metal. Sometimes the sheet metal is of a thin gauge
and a structural thread is required. The objective may be to fasten
a removable panel, to fasten a component, or to address problems of
restricted access to the back or blind side of an assembly.
Whatever the case, threaded inserts are utilized in many
applications throughout many industries.
[0375] The basic form or shape of the threaded insert is much akin
to that of the blind rivet sleeve. The blind rivet sleeve is
typically described by reference to the body and the head. The
primary difference between a blind rivet sleeve and a threaded
insert is that the threaded insert has an internally threaded
section or portion typically found at the base of the body or at
the end opposite the head.
[0376] Upon installation, a threaded insert functions much like a
blind rivet sleeve. The threaded insert is threadably mated to an
installation tool. Here the threaded insert is coupled to a mandrel
which protrudes from an anvil/nose member. Then, the threaded
insert is inserted through a hole in the work piece or component.
The head of the insert controls the insertion depth as does the
head on a blind rivet.
[0377] Next, the tool is actuated through some type of triggering
device. This, in turn starts a longitudinal motion whereby the
mandrel is pulled rearward or into the anvil/nose member. When
sufficient translation has occurred to abut the anvil/nose against
the head of the insert, a substantial load is imparted through the
mandrel which is threadably attached to the threaded section or
portion of the threaded insert internal diameter.
[0378] After sufficient load is produced by the action inside the
tool which is mechanically coupled to the mandrel, the back or
blind side of the sleeve member of the threaded insert begins to
buckle or expand similar to the body or sleeve of a blind rivet.
This expansion creates a blind side or back side head in the
threaded insert sleeve. Once the back side head is formed in the
threaded insert, the installation tool, through the employment of a
spinning action, de-couples the mandrel from the threaded insert.
Now, a mechanically fastened nut member is attached to the work
piece and may be utilized for a number of useful applications.
[0379] Through the modification of several components of the
invention disclosed herein, an automatic threaded insert
installation system can be produced. The bulk feed device would
still operate in much the same manner whereby it would elevate
threaded inserts via the paddlewheel, propel them along spinning
bars, after which they would proceed through a sorting block,
yielding properly oriented threaded inserts to an escapement
device.
[0380] The escapement device would have to be modified such that,
during the freefall to the receiver, the threaded inserts would not
be allowed to tumble and therefore lose their associated
orientation. This would be accomplished by minimizing the freefall
and modifying the receiver conical shape so as to prevent tumbling.
In some cases, threaded inserts are of such a shape that a tubular
blow feed line would not allow for a reliable transport with the
threaded insert in the most useable orientation (sleeve first and
head last). In these cases, the insert would be delivered to the
escapement in an inverted orientation, be introduced to the
receiver, and finally be propelled through the feed tube to the
installation tool.
[0381] At the tool, the threaded inset would be located, oriented,
and then secured by a presenter. Next, the presenter would be
positioned such that the threaded insert was axially aligned with
the mandrel/anvil/nose assembly. With the presenter holding the
threaded insert in the proper load location, the mandrel/anvil/nose
assembly would be translated towards the threaded insert and,
simultaneously, a mandrel spinning action would occur.
[0382] Fitted inside the nose would be a motor that would couple to
the mandrel holder or coupling. The mandrels do wear and therefore
have to be replaced periodically. Incorporated in this assembly is
a sensing circuit that insures that the mandrel is sufficiently
coupled to the threaded insert prior to the anvil/nose translating
forward and thus removing the threaded insert from the presenter.
Once the sensing circuit has verified proper threadable engagement
of the mandrel to the threaded insert, the anvil/nose assembly
would be reciprocated forward to the installation-ready
position.
[0383] Now, the operator would insert the threaded insert into a
prepared hole and a trigger actuation would activate the pulling
function in the tool.
[0384] Here, the hydraulic pressure sensing system employed in the
blind rivet system would be utilized to insure that the correct
installation load was imparted through the mandrel to the threaded
insert. Upon reaching the defined load, the mandrel/pulling
assembly would be returned forward inside the anvil/nose assembly
which would eliminate the axial load for installation. Now, the
spinning action would be actuated in the opposite direction as
before which would act to decouple the mandrel from the installed
threaded insert.
[0385] As with the blind rivet system, several processes are
simultaneously occurring in order to facilitate a minimal cycle
time. Staging of threaded insert, blow feeding, and capturing for
presentation are processes that would occur simultaneously with
installation, as is done in the blind rivet system.
[0386] Furthermore, a clip feed system similar to that employed in
the blind rivet installation system described herein would be very
useful in this application due to the fact that some nut insert
designs might prevent successful blow feeding, but could easily be
loaded into clips from a bulk feed unit outfitted to automatically
load the threaded inserts into clips.
[0387] The clip design previously described is designed in such a
manner that, through an external rotary input, the belt transport
system within the clip can be powered facilitating rapid automatic
loading. Here, these clips, either blind rivet or threaded insert
clips, can be aligned and coupled to a driving device that powers
the belt transport within the clip and then, with proper alignment
to the queue track on the bulk feed module, these clips can be
loaded economically.
[0388] The system described herein would also be able to be run as
a manual system with an operator loading threaded inserts by hand
and then performing the installation just as the invention
disclosed herein allows. Finally, as in the case of the invention,
this new automated threaded insert system facilitates the use of
robotic installation. With the automatic feed mechanisms employed,
these systems need merely to be affixed to a robot and fully
automatic installation would be attained.
[0389] An Alternative Collet Lock Actuating Assembly.
[0390] Referring, now, to FIG. 401, there is shown an alternative
collet lock actuating assembly 475. Note that, in this assembly
475, the collet lock air cylinder 461 actuates the collet lock
bracket tong 477 about pivot pin 467 so as to translate collet lock
413 as described in the description associated with stage one.
[0391] An Alternative Presentation Drive.
[0392] Referring, now, to FIG. 402A, FIG. 402B, and FIG. 402C,
there is shown an alternative presentation drive. Note that, in
this assembly, the rivet body presenter and rivet pintail presenter
are translated using an assembly of gears and racks, rather than an
assembly of chains, sprockets, gears and racks as described
hereinabove in stage nine.
[0393] Turning, now, to FIG. 402A and FIG. 402B, the presenters
543, 545 are shown in their lowermost position. Upon actuation of
presentation air cylinder 533, presentation air cylinder rack 564
will extend forward rotating gear set 565 in a clockwise direction
which, in turn, translates presentation rack 567 upwards. The
upward translation of presentation rack 567, in turn, elevates
presenters 543, 545.
[0394] Turning, now, to FIG. 402C, note that presentation rack 567
is now shown in a lower (but not lowermost) position. The
presentation rack 567 is equipped with sensor holes 570a, 570b.
These sensor holes 570a, 570b provide a communication conduit, so
that the tool controller, acting in response to signals received
from LED emitter receiver set 568a, 568b, can determine the
position of presentation rack 567. Similarly, hall sensor 572
provides input signals to the tool controller regarding the
position of presentation air cylinder 533.
[0395] Refinements to the Improved Catcher System.
[0396] Referring, now, to FIG. 403A, FIG. 403B, FIG. 403C, FIG.
403D, FIG. 403E, FIG. 403F, FIG. 403G, FIG. 403H, and FIG. 403I,
there is shown an embodiment of the improved catcher system
described hereinabove (see "A `catcher` improvement"
hereinabove).
[0397] Referring, now, to FIG. 403A, a partial cutaway is shown
which clearly demonstrates the staging of the rivets 703a, 703b,
703c within the tool. Rivet 703a is of course ready to be
installed.
[0398] Rivet 703b and rivet 703c are staged within the tool,
awaiting their respective turns for presentation. Specifically,
rivet 703b is shown in the forward, chambered position proximate to
the presenters 743, 745. By contrast, rivet 703c is shown in
position within the blow tube 702, its forward travel having been
halted by impact-absorbing stop 700.
[0399] Referring, now, to FIG. 403B and FIG. 403C, a partial
cutaway is shown which again clearly demonstrates the staging of
the rivets 703b, 703c within the tool.
[0400] Specifically, rivet 703b is shown in the forward, chambered
position. Note that the rivet head is against the bumpers 704a,b
which served to stop its forward travel. Notice as well the head of
the rivet has passed through flexible tabs 708a,b which now serve
to prevent the rivet from recoiling/rebounding rearward back
towards the blow tube 702. The position of rivet 703b is
detected/confirmed from a control standpoint by LED
emitter-receiver set 706a,b.
[0401] Rivet 703c is shown in position within the blow tube 702,
its forward travel having been halted by impact-absorbing stop 700.
Once again, its position is detected by LED emitter-receiver set
710a,b.
[0402] Turning, now, to FIG. 403D, FIG. 403E, and FIG. 403F,
various exploded, perspective views of the impact-absorbing stop
700 and various control components are shown. These figures impart
a greater overall understanding of component positions within the
tool. Specifically, the overall position of the impact-absorbing
stop 700 and the LED receiver 710b are shown.
[0403] Turning, now, to FIG. 403G, FIG. 403H, and FIG. 403I,
various views showing the operation of the impact-absorbing stop
700 are shown. Specifically, in FIG. 403H, the impact-absorbing
stop 700 is shown in the rivet halt position. This view makes clear
that the impact-absorbing stop 700 halts further progress by a
rivet 703c in the blow tube 702; however, it does not significantly
impede the flow of air in the blow tube 702.
[0404] In FIG. 403I, the impact-absorbing stop 700 is shown in its
lowered position, allowing rivets to advance from their rearward
staged position (see, e.g., rivet 703c) to their forward chambered
position (see, e.g., rivet 703b).
[0405] An Alternative Paw Stop System Embodiment.
[0406] Referring, now, to FIG. 404A, FIG. 404B, and FIG. 404C, an
alternative paw stop system embodiment is shown.
[0407] In FIG. 404A, a flag stop system, which serves the same
purpose as the paw stop system in stage eight referenced
hereinabove, is shown. In the figure, rivet 703b is shown in the
forward, chambered position, and the flag stop 869 is shown in the
stop position. In this position, the flag stop 869 is ready to
provide the resistance necessary to snap rivet 703b into a captured
position within rivet body side presenter 843.
[0408] The attentive reader will appreciate from the figures that
flag stop 869 rotates between two positions, the first shown in
FIG. 404A and the second shown in FIG. 404C. Upon actuation by the
tool controller, an air cylinder (not shown) translates flag stop
push rod 864 forward. This, in turn, rotates flag stop actuator 866
against the resistance of return spring 862 and translates the
spherical link 868 so as to rotate flag stop 869.
[0409] In FIG. 404B, the flag stop 869 is shown actually applying
the resistance necessary to snap rivet 703b into a captured
position within the now-elevated rivet body side presenter 843.
[0410] Finally, in FIG. 404C, the flag stop 869 has been rotated
clockwise (when viewed from above) so that the presentation system
can elevate rivet 703b into the rivet load position.
[0411] A Quick Release Nose Assembly Mechanism.
[0412] Referring, now, to FIG. 405A, FIG. 405B, and FIG. 405C, a
quick release nose assembly mechanism is shown.
[0413] In FIG. 405A, the tool is shown as fitted with quick release
retention tab 920. The tab 920 is shown in the closed position,
securing the nose assembly 943 to the bridge 919.
[0414] In FIG. 405B, the quick release tab 920 is shown in the open
position, allowing the nose assembly 943 to be separated from the
bridge 919 and removed from the tool. Quick removal of the nose
assembly 943 may be desirable to effectuate routine maintenance
and/or repairs or replacements. When quick release tab 920 is
elevated, as shown in FIG. 405B, quick release retention pins 922
are also elevated (against the action of quick release return
springs 918) thus disengaging nose assembly retention groove
924.
[0415] FIG. 405C depicts removal of nose assembly 943.
[0416] An Alternative Rivet Capture Mechanism.
[0417] Referring, now, to FIG. 406, an alternative rivet capture
mechanism is shown. In FIG. 406, rivet pintail presenter 1045 has
been equipped with a bar magnet 1046, and rivet body side presenter
1043 has been equipped with a ball magnet 1044. These magnets
secure rivet 1003b to the presenters for rivet loading and, as
such, serve as a substitute for the presenter "snap" fit
functionality described in stage eight.
[0418] Another Alternative Collet Lock Actuating Assembly.
[0419] Referring, now, to FIG. 501A and FIG. 501B, there is shown
another alternative collet lock actuating assembly 1175.
[0420] Note that, in this assembly 1175, the collet lock air
cylinder 1161 actuates the collet lock bracket tong 1177 about
pivot pin 1167 so as to translate collet lock 1113 as described in
the description associated with stage one.
[0421] Additional Refinements to the Improved Catcher System.
[0422] Referring, now, to FIG. 502A and FIG. 502B, there are shown
various additional refinements to the improved catcher system
described hereinabove (see "A `catcher` improvement"
hereinabove).
[0423] In FIG. 502A, the rivet 1203b is shown in its chambered
position. In this figure, the head of the rivet 1203b has abutted
the bumpers 1204a,b and is constrained in the longitudinal
x-direction direction by the action of flexible tabs 1208a,b.
[0424] Turning to FIG. 502B, the attentive reader will appreciate
that, if the bumpers 1204a,b are fashioned of an appropriate, hard,
conductive material, then, once the rivet 1203b comes into contact
with the bumpers 1204a,b, an electrical path will be created. This
presents an opportunity for yet another process control detection
mechanism. Specifically, if the tool is configured such that
conductivity across electrical contacts 1214,b is measured, then
the chambering of a rivet 1203b can be detected.
[0425] FIG. 502B also reveals the presence of vertical flexible
tabs 1212a,b. These vertical flexible tabs 1212a,b gently constrain
the body of rivet 1203b during chambering.
[0426] An alternative decoupled piston-pull rod nexis.
[0427] Referring, now, to FIG. 503A, FIG. 503B, FIG. 503C, FIG.
503D, FIG. 503E, FIG. 503F, and FIG. 503G, there is shown an
alternative embodiment of the decoupled nexis between the piston
and pull rod assembly.
[0428] Turning, now, to FIG. 503A and FIG. 503C, the attentive
reader will note that, when these figures are compared to FIG. 2A,
two components from FIG. 2A are conspicuously missing--the inner
collet 93 and actuation spring 97. Actually, several components
from FIG. 2A have been eliminated, but those two are immediately
apparent from even a casual perusal of the figures.
[0429] One of the important functions of the inner collet 93 and
its related components and subassemblies of FIG. 2A et al was to
effectuate the decoupled action of the piston 91 against pull rod
coupling 101. In FIG. 503A and FIG. 503C, which depict the tool in
a state comparable to that encountered in stage six as described
hereinabove, this decoupled action is effectuated generally as
follows.
[0430] The rearward face of piston 1391 is positioned to act
against the forwardmost face of pull rod coupling 1401. The
coupling 1401 is threadedly connected to pull rod 1355 (which, as
described above, is the direct means by which blind rivet
installation is effectuated). Pull rod coupling 1401 is also
threadedly connected to seal rod 1403 which is then connected
through a quick release mechanism to bridge 1319.
[0431] The reader will understand and appreciate that, if air
pressure is utilized to expedite piston return (as generally
described in stage five and as shown in this figure), a rear end
cap inner seal 1423 is useful for securing a substantially airtight
cavity.
[0432] Pull rod coupling 1401 is shown in this figure as being
fitted with sensor ring 1402. This ring 1402 provides a means for
detecting pin break (a means to be contrasted with the monitoring
of hydraulic pressure as described in stage four hereinabove).
Sensor ring 1402 comprises a ferrous material, so that a proximity
sensor (such as proximity sensor 139 of FIG. 6A) can detect the
motion of pull rod assembly 1373 when pin break occurs.
[0433] It will also be appreciated that, as hydraulic fluid is
introduced into piston cavity 1409, the piston 1391 will be
translated rearward (for example, as described in stage two
hereinabove). In this alternative embodiment, the rearward
translation of the piston 1391 is limited by the forwardmost face
of rear end cap 1399 which is threadedly connected to hydraulic
cylinder 1317.
[0434] Although this configuration of the piston assembly, pull rod
assembly, and their functional interconnection differs from that
shown in FIG. 2A et al, the person of ordinary skill in the art
will appreciate that the piston and pull rod assembly continue to
be decoupled. This decoupling continues to impart all of the
benefits (for example, shock mitigation, nose assembly
reciprocation) described above.
[0435] Turning, now, to FIG. 503B, the reader will understand and
appreciate that this figure appears so as to provide a high-level
overview of the exterior appearance of some of the tool components
when this alternative embodiment is employed. The reader will note,
for example, the relative position of the bridge 1319 and the
hydraulic cylinder 1317.
[0436] Another Quick Release Nose Assembly Mechanism.
[0437] Referring, now, to FIG. 504A, FIG. 504B, and FIG. 504C,
another quick release nose assembly mechanism, similar in operation
to that of 405A, FIG. 405B, and FIG. 405C, is shown.
[0438] In FIG. 504A, the tool is shown as fitted with quick release
retention tab 1520. The tab 1520 is shown in the open position,
allowing the nose assembly 1543 to be separated from the bridge
1519 and removed from the tool.
[0439] Specifically, as shown in FIG. 504B and FIG. 504C, the
bridge 1519 can now be rotated away from the nose axis 1589 (not
shown) so that the nose assembly 1543 can now be removed in a
rearward direction from the tool.
[0440] An Alternative Decoupled Piston-Pull Rod Nexis.
[0441] Referring, now, to FIG. 601, there is shown an additional
alternative embodiment of the decoupled nexis between the piston
and pull rod assembly. FIG. 601A depicts an end view of the
embodiment shown in FIG. 601. FIG. 601B depicts an enlargement of
salient sections of FIG. 601.
[0442] Turning, now, to FIG. 601B, the attentive reader will note
that, when this figure is compared to FIG. 2A, two components from
FIG. 2A are conspicuously missing--the inner collet 93 and
actuation spring 97. Actually, several components from FIG. 2A have
been eliminated, but those two are immediately apparent from even a
casual perusal of the figures.
[0443] One of the important functions of the inner collet 93 and
its related components and subassemblies of FIG. 2A et al was to
effectuate the decoupled action of the piston 91 against pull rod
coupling 101. In FIG. 601B, which depict the tool in a state
comparable to that encountered in stage six as described
hereinabove, this decoupled action is effectuated generally as
follows.
[0444] The rearward face of piston 2291 is positioned to act
against the forwardmost face of seal rod 2203. The seal rod 2203 is
threadedly connected to pull rod 2255 (which, as described above,
is the direct means by which blind rivet installation is
effectuated). Seal rod 2203 is also connected through a quick
release mechanism to the bridge (bridge not shown).
[0445] The reader will understand and appreciate that, if air
pressure is utilized to expedite piston return (as generally
described in stage five and as shown in this figure), a rear end
cap inner seal 2223 and rear end cap outer seal 2235 are useful for
securing a substantially airtight cavity.
[0446] It will also be appreciated that, as hydraulic fluid is
introduced into piston cavity 2297, the piston 2291 will be
translated rearward (for example, as described in stage two
hereinabove). In this alternative embodiment, the rearward
translation of the piston 2291 is limited by the forwardmost face
of rear end cap 2299 which is threadedly connected to hydraulic
cylinder 2217.
[0447] Although this configuration of the piston assembly, pull rod
assembly, and their functional interconnection differs from that
shown in FIG. 2A et al, the person of ordinary skill in the art
will appreciate that the piston and pull rod assembly continue to
be decoupled. This decoupling continues to impart all of the
benefits (for example, shock mitigation, nose assembly
reciprocation) described above.
[0448] The astute reader will appreciate that the embodiment shown
in FIG. 601, FIG. 601A, and FIG. 601B incorporates all of the
important teachings referenced hereinabove with respect to FIGS.
503A, 503B, 503C, FIG. 201S1 (and its related figures), and FIG.
201S2 (and its related figures). In some respects, for example, in
FIG. 601B, the seal rod 2203 is acting as a functional and
equivalent extension of the pull rod nut member 357 of FIG.
201S1.
* * * * *