U.S. patent number 3,763,541 [Application Number 05/310,789] was granted by the patent office on 1973-10-09 for method of and apparatus for setting blind fasteners.
Invention is credited to David M. Jaffe.
United States Patent |
3,763,541 |
Jaffe |
October 9, 1973 |
METHOD OF AND APPARATUS FOR SETTING BLIND FASTENERS
Abstract
Apparatus for setting fasteners having apertures therein, which
comprises a mandrel mounted for movement relative to an anvil
surface, said mandrel being adapted to receive a fastener thereon
by effecting relative axial movement between the mandrel and the
aperture in the fastener, means for expanding a portion of the
mandrel in front of the fastener to a cross-section greater than
the aperture in the fastener, and means for driving the expanded
mandrel toward the anvil surface to set the fastener.
Inventors: |
Jaffe; David M. (New York,
NY) |
Family
ID: |
23204118 |
Appl.
No.: |
05/310,789 |
Filed: |
November 30, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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142826 |
May 11, 1971 |
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62873 |
Aug 11, 1970 |
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Current U.S.
Class: |
72/393; 29/816;
72/391.4 |
Current CPC
Class: |
B21J
15/32 (20130101); B21J 15/043 (20130101); B21J
15/105 (20130101); B21J 15/365 (20130101); Y10T
29/53513 (20150115) |
Current International
Class: |
B21J
15/04 (20060101); B21J 15/36 (20060101); B21J
15/34 (20060101); B21J 15/06 (20060101); B21J
15/00 (20060101); B23q 007/10 (); B23p
011/00 () |
Field of
Search: |
;29/2H,2B,212D,509,243.52,2P ;72/446X |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Eager; Thomas H.
Parent Case Text
This is a continuation of Ser. No. 142,826, filed May 11, 1971, now
abandoned, which was a continuation-in-part of Ser. No. 62,873,
filed Aug. 11, 1970, now abandoned.
Claims
I claim:
1. Apparatus for setting fasteners having apertures therein, which
comprises:
a mandrel assembly adapted to be expanded from an unexpanded mode
to an expanded mode mounted for movement relative to an anvil
surface, said mandrel assembly being adapted to receive a fastener
thereon in its unexpanded mode by effecting relative axial movement
between the mandrel assembly and the aperture in the fastener, the
mandrel assembly in its unexpanded mode occupying substantially the
entire cross-sectional area of the aperture in the fastener when
the fastener is received thereon,
means for expanding the mandrel assembly to its expanded mode
wherein a portion thereof has a cross-section greater than the
aperture in the fastener, and
means for driving the expanded mandrel assembly toward the anvil
surface to set the fastener.
2. Apparatus according to claim 1, wherein:
the mandrel assembly includes a shaft having an enlarged front
portion.
3. Apparatus according to claim 2, wherein the enlarged front
portion of the shaft includes a tip tapered to a point from a base
having a cross-section larger than that of the shaft and a portion
of decreasing cross-section between the base of the tapered tip and
the shaft proper.
4. Apparatus according to claim 2, wherein the means for expanding
the mandrel assembly includes a sleeve of resilient material
mounted for slidable movement on the mandrel to and from a position
whereat the leading edge thereof is mounted adjacent the thickest
part of the enlarged front portion thereof, said sleeve being
segmented adjacent the leading edge thereof.
5. Apparatus according to claim 4, wherein:
the mandrel shaft is circular in cross-section and the enlarged
front portion of the mandrel includes a tapered conical tip and a
frustoconical portion of decreasing cross-section between the base
of the conical tip and the shaft, and
the sleeve is tubular and the segments thereof are in cross-section
sections of an annular ring.
6. Apparatus according to claim 4, wherein:
the mandrel shaft is circular in cross-section and the enlarged
front portion of the mandrel includes a tapered conical tip and a
frustoconical portion of decreasing cross-section between the base
of conical tip and said shaft, and
said sleeve is tubular and at least portions of the segments
thereof are triangular in cross-section, one apex of the triangle
being pointed radially outwardly to engage and sever the end of the
fastener.
7. Apparatus according to claim 4, wherein:
at least a portion of the mandrel shaft is of triangular
cross-section and the enlarged front portion of the mandrel
includes a tapered conical tip and a substantially frustoconical
portion of decreasing cross-section between the conical tip and the
triangular cross-section, the substantially frustoconical section
including triangular flats faired into the sides of the triangular
shaft, and
the sleeve segments are secant sections of a circle circumscribed
about the triangle of the shaft cross-section.
8. Apparatus for setting fasteners having apertures,
comprising:
a housing including an anvil surface with an aperture therein,
a mandrel assembly mounted in said housing and extending out of
said aperture, said mandrel assembly being adapted to be expanded
from an unexpanded mode to an expanded mode and to receive a
fastener thereon in its unexpanded mode for setting by effecting
relative axial movement between the mandrel assembly and the
aperture in the fastener, the mandrel assembly in its unexpanded
mode occupying substantially the entire aperture in the fastener
when the fastener is received thereon,
means for expanding the mandrel assembly on the side of the
fastener away from the anvil surface to a cross-section greater
than the diameter of the aperture in the fastener, and
means mounted in said housing for driving said expanded mandrel
assembly relative to said anvil surface to set the fastener, said
means including a cylinder and a piston reciprocal in the cylinder
and connected to said mandrel assembly.
9. Apparatus according to claim 8, wherein:
said mandrel assembly includes a shaft having an enlarged front
portion, and
the means for expanding the mandrel assembly includes a sleeve
having a segmented front portion, said sleeve being mounted on the
mandrel shaft for movement relative thereto to and from a position
whereat at least a portion of the segmented front thereof is
adjacent the thickest part of the enlarged front portion of the
mandrel shaft such that the thickness of the sleeve segments is
added thereto.
10. Apparatus according to claim 9, wherein the means for moving
the sleeve relative to the mandrel shaft includes an enlarged
portion provided on said sleeve at the rear thereof and a collar
mounted on said mandrel and movable within said enlarged sleeve
portion upon the rearward movement of the piston.
11. Apparatus according to claim 8, wherein:
a chamber is provided in said housing between said anvil surface
and said cylinder, said chamber communicating with said aperture in
the anvil surface,
said mandrel assembly includes:
a shaft portion extending from the piston through said chamber and
out said aperture,
an enlarged front portion mounted on the end of the shaft portion
extending from the aperture, and
a collar portion mounted on the shaft portion in said chamber,
said means for expanding the mandrel assembly includes a member
mounted for slidable movement with respect to said shaft and having
a sleeve portion with a segmented front end extending through said
aperture to a position normally adjacent the enlarged front portion
of the mandrel shaft and a hollow, enlarged portion connected to
said sleeve portion and mounted for movement in said chamber, said
hollow enlarged portion enclosing said collar on the shaft,
rearward movement of the piston being operable to first expand the
mandrel assembly as the enlarged shaft portion is moved relative to
the sleeve segments and the latter surround at least a portion of
the enlarged front end, adding their thickness thereto, and
further rearward movement of the piston being operable to drive the
expanded mandrel assembly into the fastener as the collar strikes
the rear of the hollow enlarged portion of the expanding member and
carries it to the rear along therewith.
12. Apparatus according to claim 9, wherein said driving means
further includes a spring mounted between the back of the piston
and the back of the cylinder to bias the enlarged front of the
mandrel shaft away from said anvil surface and means for admitting
fluid to said cylinder in front of said piston to expand the
mandrel assembly by causing movement of the sleeve relative to the
mandrel shaft and to drive the expanded mandrel assembly toward
said anvil surface.
13. Apparatus according to claim 11, wherein the shaft portion of
the mandrel is circular in cross-section and the enlarged front
portion of the mandrel shaft includes an enlarged conical tip and a
frustoconical portion of decreasing cross-section between the base
of the conical tip and the shaft.
14. Apparatus according to claim 13, wherein:
said chamber is cylindrical, said sleeve is tubular, said segments
are arcuate in cross-section and the leading edges thereof are
flared outwardly, and
the enlarged portion of the expanding member is tubular with front
and rear walls slidable on the mandrel shaft portion, the tubular
periphery being slidable in said cylindrical chamber.
15. Apparatus for setting fasteners having apertures therein, which
comprises:
a housing,
a nose mounted at one end of the housing, said nose including an
anvil surface having an aperture therein,
a mandrel mounted for reciprocal movement in said housing,
means for loading a fastener on the mandrel,
means for driving the mandrel through a forward stroke wherein the
portion thereof having the fastener loaded thereon extends out the
nose,
means for expanding the effective cross-section of the end portion
of the mandrel beyond that of the fastener aperture after the
forward stroke of the mandrel, and
means for driving the expanded end of the mandrel toward said anvil
surface to set the fastener.
16. Apparatus according to claim 15, wherein:
said mandrel includes a shaft portion and an enlarged front
portion, and
said means for expanding the mandrel includes a sleeve mounted for
slidable movement on the shaft for movement to and from a position
adjacent the thickest part of the enlarged front portion of the
mandrel.
17. Apparatus according to claim 15, wherein said nose
includes:
a plurality of segments hingedly mounted to the housing, and
means for biasing said nose segments to a position wereat they are
operable to pass the fastener loaded mandrel therethrough from the
housing out, but only to pass the mandrel therethrough into the
housing, thus providing the anvil surface for the setting of the
fastener.
18. Apparatus according to claim 15, wherein said means for loading
a fastener on the mandrel includes:
means for supporting the fastener in said housing wherein the
aperture therein is in spaced relationship with the mandrel,
and
means for gating a fastener onto said support in a timed
relationship with the reciprocal movement of the mandrel.
19. Apparatus according to claim 15, wherein said means for driving
said mandrel includes a cylinder provided in said housing, a piston
mounted on the mandrel and reciprocal in said cylinder, a spring
mounted between the back of the cylinder and the back of the piston
for driving a portion of the mandrel out of the nose and means for
admitting compressed air into the cylinder in front of the piston
to set the fastener on the portion of the mandrel extending out of
the nose and drive the mandrel portion back inside the housing.
20. Apparatus according to claim 16, wherein said means for
expanding the mandrel further includes:
a tubular member mounted to said sleeve at the rear thereof and
slidable along therewith on said mandrel, said tubular member
including a front and a back, and
a collar mounted on said mandrel and within said tubular member
wherein initial driving movement of the mandrel effects the
expansion of the end portion of the mandrel since the segmented end
of the sleeve moves to said position adjacent the thickest portion
thereof and when the collar strikes the rear of the tubular member
the thus expanded mandrel is driven back into the fastener.
21. Apparatus according to claim 6, wherein said mandrel shaft
conical portion includes a sharp tip for puncturing apertures in
work for the receiving of fasteners therein.
22. An apparatus for setting fasteners having apertures therein,
which comprises:
a mandrel mounted for movement relative to an anvil surface, said
mandrel including a shaft having an enlarged front portion, at
least a portion of the shaft being of substantially polygonal
cross-section and the enlarged front portion of the mandrel
including a generally frustoconical portion of decreasing
cross-section between the leading edge thereof and the polygonal
cross-section portion of the shaft, said generally frustoconical
section including flats faired into the sides of the polygonal
shaft,
a sleeve mounted on the mandrel, the front portion of said sleeve
being segmented, said sleeve segments having generally flat
interiors disposed opposite the sides of the polygonal
cross-section portion of the shaft,
means for sliding said sleeve relative to the mandrel to and from a
position whereat the leading edge of the sleeve is positioned on
the enlarged front portion at a point whereat the effective
cross-section of the mandrel and sleeve segments are greater than
the aperture in the fastener, the generally flat interior of the
sleeve segments sliding on the flat of the frustoconical portion of
the mandrel, and
means for driving the expanded mandrel towards the anvil surface to
set the fastener.
23. Apparatus according to claim 22, wherein the cross-section of
the mandrel shaft is substantially triangular, the flats of the
frustoconical portion are generally triangular in shape, the sleeve
segments are secant sections of a circle circumscribed about the
triangle of the shaft cross-section and the enlarged front portion
of the mandrel includes a tapered tip.
24. Apparatus according to claim 1, wherein the mandrel assembly
occupies substantially the entire cross-sectional area of the
aperture in the fastener for at least a significant portion of the
length thereof when the fastener is placed on the mandrel assembly
in its unexpanded mode.
25. An apparatus for setting fasteners having apertures therein,
which comprises:
a mandrel mounted for movement relative to an anvil surface, said
mandrel including a shaft having an enlarged front portion, at
least a portion of the shaft being of substantially polygonal
cross-section and the enlarged front portion of the mandrel
including a generally frustoconical portion of decreasing
cross-section between the leading edge thereof and the polygonal
cross-section portion of the shaft,
a sleeve mounted on the mandrel, the front portion of said sleeve
being segmented, said sleeve segments having generally flat
interiors disposed opposite the sides of the polygonal
cross-section portion of the shaft,
means for sliding said sleeve relative to the mandrel to and from a
position whereat the leading edge of the sleeve is positioned on
the enlarged front portion at a point whereat the effective
cross-section of the mandrel and sleeve segments are greater than
the aperture in the fastener, and
means for driving the expanded mandrel towards the anvil surface to
set the fastener.
26. Apparatus according to claim 25, wherein the cross-section of
the mandrel shaft is substantially triangular, the sleeve segments
are secant sections of a circle circumscribed about the triangle of
the shaft cross-section and the enlarged front portion of the
mandrel includes a tapered tip.
Description
BACKGROUND
This invention relates to fasteners and more particularly to an
improved method of and apparatus for setting blind fasteners.
In many situations it is desired to fasten two pieces of material
together when only one side of the work is accessible. When this is
to be effected by a fastener such as a nail or a screw, it is
relatively simple to drive the fastener into a fastening position.
However, when the nature of the material, or its application,
require that a blind rivet or the like be used, difficulties arise
in the setting of the fastener, since the work separates the
portion of the fastener to be set and the fastening tool.
Many approaches have been taken to overcome this problem. For
example, blind rivets have been fabricated with a headed nail
thereon, whereupon the rivet is placed in the holes in the work
with the head thereof on the far side, and the nail is pulled from
the near side of the work, the nail head deforming the far side of
the rivet and thus setting the rivet in the work. The nail remains
held in the rivet and the portion of the nail protruding from the
near side thereof is broken off. Obviously, this is a wasteful and
time consuming operation.
In another approach, a plurality of rivets having tapered openings
are loaded on a single mandrel having an enlarged head. In
operation, the leading rivet and the portion of the mandrel on
which it is mounted are inserted in the hole and the mandrel is
drawn back one rivet length, setting the rivet as it passes
therethrough and readying the apparatus for the next operation.
This is unsatisfactory since rivets must be precisely mounted on
the mandrel in a costly and time consuming manner and mandrels have
to be replaced after a predetermined number of rivets are set.
In a still further approach, apparatus has been devised wherein the
rivet is placed in a hole and a tool including a hook is placed
through the rivet and rotated as it is drawn back, setting the
rivet. This approach is also time consuming and costly.
SUMMARY
It is, therefore, an object of this invention to provide an
improved method of and apparatus for setting blind fasteners.
It is another object of this invention to provide a rivet setting
system wherein the setting tool may freely pass through a fastener
in a first mode and be operable to set the fastener in a second
mode.
It is a more specific object of this invention to provide a rivet
setting system including an expandible mandrel wherein in an
unexpanded mode the mandrel may receive a fastener thereon for
setting and in an expanded mode set the fastener.
It is a still more specific object of this invention to provide a
fastener setting tool including an expandible mandrel mounted for
rectilinear movement with respect to an anvil surface and operable
to receive a fastener thereon in a first mode and to be expanded
such that it is operable to set the fastener thereon when the tool
is actuated to move the mandrel relative to the anvil surface.
It is a further object of this invention to provide an improved
mandrel assembly adapted to be inserted in one side of a blind
fastener and set it from the other side.
It is a still further object of this invention to provide a system
wherein a reciprocable member picks up a fastener at one point of
its cycle and sets it at another point of its cycle.
It is yet another object of this invention to provide a
semi-automatic system for setting a succession of blind
fasteners.
In accordance with these and other objects apparatus according to
the invention may comprise a mandrel, means for driving the mandrel
through a cycle including forward and reverse portions, means for
mounting a fastener on the mandrel prior to the reverse portion of
the cycle, and means fo increasing the effective diameter of a
portion of the mandrel for at least a portion of the reverse
portion of the cycle to set the fastener mounted thereon.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of a hand loaded fastening tool
according to the invention.
FIG. 2a is an isometric view of a portion of the mandrel assembly
shown in FIG. 1 as viewed from line 2--2 of FIG. 1.
FIG. 2b is an isometric view of a portion of an alternate
embodiment of the mandrel assembly shown in FIG. 1 as viewed from
line 2--2 of FIG. 1.
FIGS. 2c and 2d are front views of a third embodiment of the
mandrel assembly shown in FIG. 1.
FIG. 2e is a side elevation view of a portion of the embodiment
shown in FIGS. 2c and 2d.
FIG. 3 is a side elevation view of a semi-automatic fastening tool
according to the invention.
FIG. 4 is an enlarged side elevation view of a portion of the
fastener support sub-assembly shown in FIG. 3.
FIG. 5 is a front view of the fastening tool shown in FIG. 3.
FIG. 6a-6c depicts a cycle of operation of the fastening tools
shown in FIGS. 1-5.
FIG. 7 is a schematic view of a portion of the collar and cylinder
of another embodiment of a fastening tool according to the
invention.
FIG. 8 shows a development of a portion of the cylinder shown
schematically in FIG. 7.
FIGS. 9A-9D show a cycle of operation of the alternate embodiment
of the fastening tool shown in FIGS. 8 and 9.
FIGS. 10-12 depict improved fasteners for use with the embodiment
shown in FIGS. 7 and 8.
FIG. 13 is an elevation view of a fixture employing features of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the drawings, a preferred embodiment of the
invention comprises an expandible mandrel assembly 10 that is
adaptable to pass through the hole in a fastener in one mode and to
be expanded such that it is operable to set the fastener in a
second mode.
The expandible mandrel assembly is shown in connection with a hand
loaded tool in FIG. 1, in a semi-automatic hand tool in FIGS. 3-5,
and a fixture in FIG. 13. FIGS. 2a-2e disclose three
cross-sectional configurations of the mandrel assembly. FIGS. 6a-6c
show an operation sequence of the setting of one type of blind
fastener by the embodiments of FIG. 1 and FIGS. 3-5. FIGS. 7 and 8
disclose an alternate configuration of the mandrel assembly adapted
for the setting of a different type of fastener and usuable with
the tools of FIG. 1 and FIGS. 3-5. FIGS. 9A-9D show an operation
sequence of the embodiment of FIGS. 7 and 8 and FIGS. 10-12 show
three new blind fasteners made possible by the embodiment of FIGS.
7 and 8.
With reference to FIG. 1 of the drawings, a basic hand tool 8
incorporating features of the invention may comprise in a preferred
embodiment an expandible mandrel assembly 10 which is connected to
a piston 12 mounted for reciprocal movement in a cylinder 14. The
expandible mandrel assembly is mounted in a head 16 detachably
connected to the rest of the tool 8 and including a chamber 17
therein in axial alignment with cylinder 14. The backward stroke of
the piston 12 is powered by a pneumatic-hydraulic operating
mechanism 18 and the forward stroke is powered by a spring 22
mounted between the piston 12 and the back of cylinder 14.
The means for reciprocating the expandible mandrel assembly, i.e.,
the spring mounted piston and the pneumatic-hydraulic operating
mechanism, are old in the art and are commercially available. One
available tool having these parts is the Gesipa PH-I. Lever and cam
type hand tools that perform the same function are also
available.
The expandible mandrel assembly 10 that forms a preferred
embodiment of the invention includes a shaft 24 connected to piston
12 and reciprocal therewith. The shaft is dimensioned such that a
substantial portion thereof extends out of the head 16 through an
aperture 26 provided therein, as seen in FIG. 1.
The frong end 28 of shaft 24 is enlarged by a diverging
frustoconical portion 30 and then tapered to a point by a conical
portion 32. A collar 34 is mounted on shaft 24 substantially to the
rear of the front end thereof and within the cylinder 40 for a
purpose made clear hereinbelow.
A mandrel expanding member 36 is slidably mounted on shaft 24 and
includes a sleeve portion 38 and a hollow cylinder portion 40. The
hollow cylinder encloses collar 34 as shown in FIG. 1 and is
slidable with respect to the interior wall of chamber 17. With this
arrangement, the member 36 is movable along with shaft 24 when
collar 34 engages either the front or rear wall of cylinder 40 and
is movable with respect to shaft 24 during the initial portions of
either a forward or reverse stroke of the shaft 24 a distance equal
to the travel of collar 34 within the cylinder 40. A spring 41 is
mounted in chamber 17 between the back of cylinder 40 and the back
of the chamber.
The forward end of the sleeve 38 is split into a plurality of
segments 42, preferably three as shown in FIGS. 2a-2c, but not
limited to that number, which are made of strong but flexible
material.
The shaft, sleeve, cylinder and collar are dimensioned and arranged
such that after a forward stroke of the expandible mandrel assembly
is effected by the spring 22, a fastener may be placed on the
assembly since the portion thereof having the largest
cross-section, the forward portion of shaft frustoconical portion
30, will accept the hole in the particular fastener being
utilized.
The portion of the shaft extending out of head 16 through aperture
26 is made long enough to accept the fastener at the rear thereof
and still have the head of the shaft entirely in front of the
fastener. The aperture 26 is of slightly greater diameter than the
sleeve 38 such that the shaft and sleeve may freely slide therein.
However, the front end of the shaft cannot pass therethrough nor
can a fastener mounted on the mandrel assembly.
Upon the actuation of the pneumatic-hydraulic mechanism 18, the
shaft 24 will move rearwardly with respect to member 36 the
distance of the stroke of collar 34 in cylinder 40. The effect of
this movement is to make the segmented end of sleeve 38 ride up on
frustoconical portion 30 to increase the effective diameter of the
mandrel assembly at this point such that it will not pass freely
through the hole in the fastener. The spring 41 assures this
expansion of the mandrel assembly upon the initial portion of the
rearward stroke of the pneumatic-hydraulic mechanism 18, since it
biases the cylinder 40 in the forward portion of chamber 17 while
the shaft 24 retracts the collar 34.
Thus, when the collar 34 strikes the rear wall of cylinder 40 and
carries the member 36 to the rear along therewith, the mandrel will
be operable to engage and set the fastener as the fastener is
captured between the expanded mandrel front end and the front of
the head 16.
With reference to FIG. 2a, one configuration of the mandrel
assembly could include a shaft 24 that is circular in cross-section
and a tubular sleeve 38. A tubular sleeve 38 results in arcuate
segments 42 which are of a different curvature than frustoconical
portion 30 of the shaft. The sleeve material is selected to be
resilient enough such that when the shaft is retracted and the
segments 42 are caught between the frustoconical portion 30 and a
fastener, they will conform to the curvature of the frustoconical
portion and set the fastener evenly around its periphery.
An alternate configuration of the mandrel assembly is shown in FIG.
2b and is particularly suitable to applications wherein materials
other than metal are being jointed, for example, plastic and/or
cloths. The shaft 24' is circular in cross-section, as in the
previous embodiment. The back of the sleeve 38 is still tubular,
but the segments 42' at the leading portion thereof are triangular
in cross-section. When the mandrel assembly assembly of this
embodiment is retracted, the edges of the triangular segments
engage the fastener and sever the barrel thereof at the far side.
This causes the far side of the fastener to curl toward the
material and set them.
A mandrel assembly configuration having particular strength is
shown in FIGS. 2c, 2d and 2e. In this embodiment, the shaft 24" is
triangular in cross-section and the segments 42" are in
cross-section a secant closing off a circular arc that is a portion
of a circle circumscribed around the triangle of the shaft. The
segments are sized such that the secant is the same length as the
length of each side of the triangle and thus, in the unexpanded
position of the mandrel assembly, the flats of the three segments
are flush with the sides of the triangular shaft and the
peripheries thereof form a circle.
The frustoconical portion 30" of this embodiment of the shaft
includes triangular flats 44 with their apices adjacent the back of
the conical head 32 and their bases leading into the sides of the
triangular shaft. Thus, when the shaft is retracted to expand this
embodiment of the mandrel, the segments 42" slide up the flats 44
and engage the fasteners for setting at the midpoints of their
arcuate periphery, as shown in FIG. 2e.
It is to be understood that, unless otherwise stated, each of the
configurations of the mandrel assembly set forth hereinabove is
usable in the tools and embodiments described herein, and when the
mandrel assembly is mentioned hereinbelow, it is to be taken as
being interchangeably one of the configurations shown in FIGS. 2a,
2b and 2c-2e.
The setting stroke of the mandrel assembly is the backward stroke,
which is powered by the pneumatic-hydraulic mechanism 18. The
mechanism includes a housing 46 having a pneumatic section 48 and a
hydraulic section 50. A piston 52 is mounted in pneumatic section
and is driven by a house supply of compressed air delivered thereto
through a hose 54 and a port 56. A trigger 58 operates a valve 60
that controls the flow of air to the pneumatic section.
A piston rod 62 is connected to piston 52 and extends through a
suitable seal and guide assembly 64 into hydraulic section 50 where
it is attached to a piston 66 mounted therein. A upply of hydraulic
fluid is contained in the hydraulic section to the left of the
piston 66 and in cylinder 14 below piston 12, with a port 68
allowing fluid to flow therebetween. A seal assembly 70 seals head
16 from the hydraulic fluid in cylinder 14.
In operation, upon actuation of the trigger 58, piston 52 is driven
to the left as seen in FIG. 1, driving piston 66 along therewith.
The velocity of the movement of the piston assembly is controlled
by the size of port 68, but in any event is slowed by the
resistance of the hydraulic fluid. The driving of the fluid into
cylinder 14 by piston 66 causes piston 12 to be driven back in the
cylinder against the bias of spring 22.
A relief port 72 provided in the pneumatic section permits the
action of spring 22 to overcome the air pressure in the pneumatic
section once the trigger is released and air is no longer being
injected therein. The spring drives the piston down in the cylinder
14, the hydraulic fluid below the flange being forced back into the
hydraulic section of the housing through port 68 and moving the
piston assembly to the right, as seen in FIG. 1. The driving of the
piston 12 down the cylinder 14 first unexpands the mandrel assembly
and then drives the assembly outwardly.
In FIGS. 6a-6c, the apparatus is shown in operation sequence
setting a fastener having a tapered hole wherein the forward
portion of the hole is larger than the unexpanded mandrel but
smaller than the expanded mandrel. In FIG. 6a the mandrel assembly
is in its forward, unexpanded, mode, when the hand tool is picked
up for use. A fastener is placed by hand on the portion of the
mandrel assembly that extends out of head 16.
The trigger 58 is then operated, driving piston 12 and thus shaft
24 back in cylinder 14 and head 16 respectively. The initial
backward movement causes the shaft 24 to move rearwardly with
respect to the segments 42 of the mandrel expanding member 36, thus
expanding the effective cross-section of the head of the mandrel,
as discussed in detail hereinabove. Continued backward movement of
the shaft 24 causes collar 34 to drive the entire mandrel assembly
to the rear, whereupon the expanded head of the mandrel engages the
far side of the fastener and sets it (FIG. 6b).
The leading portion of head 16 is flat such that the head of the
fastener is flush therewith and provides an "anvil" when the
expanded mandrel exerts its rearward force against the front of the
fastener. With the type of fastener shown in FIGS. 6a-6c, after
setting the front of the fastener, the mandrel then reaches the
portion of the hole where the diameter thereof is greater than the
expanded mandrel. The mandrel assembly then retracts until the
enlarged head portion engages aperture 26, which will not pass it
through. The trigger is then released, allowing the mandrel
assembly to unexpand and return to its start position where it can
accept another fastener for setting.
In addition to setting a fastener having a tapered hole, the
pneumatic-hydraulic tool 8 is operable to set an eyelet type of
fastener. An eyelet fastener includes a flange and a barrel having
a hole of constant diameter therethrough. As stated hereinabove,
one widely used method for the blind setting of eyelet fasteners is
to equip it with a headed nail, the head of the nail being in the
front of the barrel and the shank of the nail being in the front of
the barrel and the shank of the nail extending from the flange end.
The eyelet is set by grasping the shank of the nail and pulling it
to the rear, thus forcing the head of the nail back into the barrel
of the eyelet to deform and set it. The portion of the nail shank
protruding from the flange of the eyelet is then severed and
disposed of.
The use of the expandible mandrel assembly and the tool 8 to set
the eyelet fastener completely eliminates the need of equipping it
with the headed nail and the resultant saving in time and material
cost is manifest.
In operation, the eyelet is placed on the portion of the unexpanded
mandrel assembly extending from the head 16, the thus loaded
mandrel is placed in the work and trigger 58 is actuated. The
mandrel assembly is first expanded and then driven back into
engagement with the front of the eyelet, deforming and pressing the
front thereof back into the work. The flat front of head 16 forms
an anvil for the setting process.
Upon release of the trigger 58, the spring 22 first unexpands the
mandrel and then returns the mandrel assembly to the start
position. The unexpanded mandrel is then removed through the hole
in the set fastener by moving the tool 8 away from the work.
With reference to FIGS. 3-5 of the drawings, a preferred embodiment
of a semi-automatic fastening tool according to the invention
generally comprises a housing 74 having therein a pair of axially
aligned cylindrical chambers 76 and 78 separated by a wall 80. A
fastener supply assembly 82 supplies fasteners one at a time into
chamber 76 through an escapement mechanism 84, a support 86
retaining the fasteners in position in the chamber 76.
A mandrel assembly 88 similar to mandrel assembly 22 is supported
in wall 80 and is reciprocated by a drive arrangement 90 mounted in
chamber 78 such that the mandrel assembly is operable to pick up a
fastener on support assembly 86, carry it out through a nose 92
mounted at one end of housing 74 in communication with chamber 76,
set it, and be retracted back into housing 74 for a new cycle. The
drive arrangement is operated by a trigger 94 mounted on a hand
grip 96.
More specifically, fastener supply assembly 82 comprises a chute
100 having a portion 102 with a T-shaped cross-section for
receiving the flanged portion of the fasteners. The thickness of
the "cross bar" of portion 102 is greater than the thickness of the
flanges of the fasteners so that the fasteners can arrange
themselves in a line with the flanges thereof overlapping. The back
of the T-shaped portion 102 also extends into the chamber 74 for
preventing fasteners from falling backwards in the chamber and
includes a cut out portion 104 so that the mandrel assembly can
pass therethrough.
The escapement mechanism 84 is operable to provide one fastener at
a time from the supply assembly into chamber 76 through an opening
106 in housing 74 in a predetermined relationship with the cycle of
the mandrel assembly. The escapement mechanism includes a first
slat 108 mounted for slidable movement in the housing wall to and
from a position whereat the leading edge thereof blocks the chute
100. A spring 110 connected at one end thereof to the housing and
at the other end thereof to the slat biases the slat 108 in its
closed position. The slat 108 includes a portion 112 angled into
chamber 76 so as to be in the path of the mandrel assembly as it
reciprocates.
A second slat 114 is mounted for slidable movement in the housing
wall and includes a stop bar 116 supported by a vertically
extending member 118. The slat 114 is movable to and from a normal
position whereat stop bar 116 blocks chute 100 at a point spaced
approximately one fastener thickness above slat 108. A portion 120
of slat 114 is angled into chamber 76 so that it may also be
engaged by the mandrel assembly and a spring 122 mounted between
the slat and the housing biases the slat into its blocking
position.
The slats 108 and 114 are operated alternately by the mandrel
assembly as will be discussed more fully below such that a single
fastener is released into chamber 76 prior to each forward stroke
of the mandrel assembly.
The support assembly 86 includes a fastener support tray 124 having
a fastener barrel support 126 and an arcuate camming surface 128
connected to each of the sides thereof. The tray 124 is pivotally
mounted on a pin 130 for movement downwardly into a recess 132
provided therefor in housing 74. A spring 134 biases the tray into
its upward position.
A fastener gated through the escapement mechanism 84 falls onto
tray 124 where it rests as shown in FIG. 4, i.e., with its barrel
on support 126 in spaced relationship with the mandrel assembly and
the flanged end retained in place by the bottom of chute 100. When
the mandrel assembly picks up the fastener and carries it forward,
the flanged end will engage camming surface 128 forcing the tray
into recess 132 to allow the flange to pass the support
assembly.
The nose 92 includes a plurality of tapered segments 136 that are
hinged to the housing by spring connections 138 such that the nose
is biased into its closed position shown in solid lines in FIG. 3.
The front of each segment is flanged and cut to form a flat nose
front having an aperture 140 therein. The diameter of aperture 140
is slightly larger than the largest diameter of the mandrel
assembly in its unexpanded mode, but smaller than that of the
mandrel nose assembly in its expanded mode.
The mandrel assembly 88 is similar to that described in the
previous embodiment and the same numerals are used to indicate the
same parts. The shaft 24 and mandrel expanding member 36 of this
embodiment are somewhat longer than in the previous embodiment and
have a greater re-ciprocatory stroke. In addition, a plurality of
fingers 142 are mounted on the shaft a predetermined distance from
the front end thereof and extend radially therefrom through the
splits in the sleeve 38 between segments 42.
The mandrel assembly is reciprocated by the drive arrangement 90
which includes a piston 146 mounted for slidable movement in
chamber 78 and having a piston rod 148 extending therefrom and
connected to shaft 24. A spring 150 is mounted between the piston
and the back end of chamber 78. An air duct 152 enters chamber 78
at the front thereof and communicates with an air hose 154 that is
connected in turn to a house supply of compressed air. A valve 156
controls the flow of air to the chamber 76 and is actuated by
trigger 94 on grip 96.
A pair of relief valves 158 and 160 mounted in ports 162 and 164
respectively are provided in housing 74 to port the air in chamber
78 on both sides of piston 146 to the atmosphere when the piston is
driven toward the respective ducts.
The length of chamber 78 and thus the stroke of piston 146 is
selected such that, upon the forward stroke of the piston, fingers
142 are flush with the front of nose 92. A plurality of cutouts 165
are pro-vided in the nose segments 136 to accommodate the fingers
142 therein.
Referring now to FIGS. 3-5 and 6a-6c, in operation, the tool as
seen in FIG. 3 is near the start of its forward stroke, which is
powered by spring 150. A fastener is in place on support assembly
86 since on the last portion of the back stroke of the previous
cycle the back of the cylinder 40 engaged the angled portion 112 of
slat 108, retracting it against the bias of spring 110 to allow the
bottommost fastener to fall into chamber 76 and onto the support
assembly 86.
As the mandrel assembly is driven forward, it passes through the
cut-out portion 104 in chute 100 and the hole in the fastener, the
fastener being picked up by the fingers 142 and resting on sleeve
38. As the mandrel assembly proceeds still further forward, the
leading edge of cylinder 40 engages angled portion 120 of slat 114
and carries the slat forward against the bias of spring 122 to
allow the stack of fasteners to drop onto slat 108, which has been
returned to its closed position by spring 110 as the mandrel
assembly moved forward.
The leading portion of the mandrel assembly with the fastener
thereon now exits through the nose 92, the head of the fastener
camming open the nose segments to allow the fastener loaded mandrel
assembly therethrough. The spring connections 138 close the nose
behind the head of the fastener, and the fastener is placed in the
hole in the work, see FIG. 6a.
After the fastener has been placed in the work trigger 94 is
depressed, opening valve 156 to permit compressed air to drive
piston 146 back in the chamber 78. The initial portion of the back
stroke retracts the shaft 24 with respect to sleeve 38 to expand
the mandrel, in the manner set forth hereinabove in connection with
the embodiment shown in FIG. 1, to beyond that of the forward end
of the fastener.
Thus, when the collar 34 strikes the rear of cylinder 40 and causes
the entire mandrel assembly to retract, the sleeve segments 42 will
engage and flare the front end of the fastener, the nose front
acting as an anvil, supporting the head of the fastener as the
sleeve segments exert its rearward force on the front of the
fastener (FIG. 6b) and, as the expanded mandrel front portion
reaches the portion of the fastener having a larger hole
cross-section than itself, the mandrel assembly passes through the
fastener, back through the nose, which is cammed opened by the
frustoconical surface of the mandrel assembly, and into chamber 76,
leaving a set fastener (FIG. 6c).
As the mandrel assembly approaches the position shown in FIG. 1 the
spring 122 forces slat 114 back into the chute 100 to support all
the fasteners therein except the lowermost one and then the back of
cylinder 40 will engage the angled portion 112 of slat 108 and
drive it back, allowing the bottommost fastener to fall into
support assembly 86 for the next cycle. The initial portion of the
next forward stroke drives collar 34 forward in cylinder 40 to
unexpand the mandrel assembly prior to the forward stroke of the
assembly towards and out the nose 92.
With reference to FIGS. 7, 8 and 9A-9D, an alternate embodiment of
the invention involves a modified shaft collar, designated 34',
operating in a modified cylinder, designated 40'. The modified
shaft collar 34' includes two diamond shaped key members 166
adapted to move in a keyway 168 formed in the inner face of
cylinder 40'. The configuration of keyway 168 is best seen in FIG.
8, which is a development of the cylinder 40'. All other elements
of this embodiment of the invention are the same as the embodiment
described hereinabove in connection with FIGS. 3-5 and are
designated by the same numerals.
The operation sequence of the fastener system of this alternate
embodiment is a four stroke cycle wherein eyelet type fasteners can
be set. At the beginning of the cycle, the spring 150 drives the
mandrel assembly 22 forward, picking up a rivet from the feed and
support assemblies and driving the fastener out the nose of the
tool in a manner identical to the embodiment of FIGS. 3-5. At this
time, the fastener and mandrel are placed in the hole in a piece of
work, as seen in FIG. 9A.
The trigger 94 is then depressed, sending compressed air into the
front of chamber 78 and driving piston 146 backwards. Initially,
this drives collar 34' back in cylinder 40', with the key members
166 moving back in keyway 146 from the points designated A in FIGS.
7 and 8 to the points designated B, or all the way to the back wall
of the cylinder.
This expands the mandrel, since the frustoconical shaft portion 30
of the mandrel retracts with respect to sleeve 38 in the same
manner as discussed hereinabove to increase the diameter of the
head of the mandrel to beyond that of the hole in the fastener.
Further backward travel of piston 146 drives the expanded mandrel
back into the leading edge of the rivet, with the frustoconical
shaft portion 30 setting the leading edge of the fastener, as seen
in FIG. 9B. The backward travel of the mandrel assembly back
through the fastener and the nose, as in the system of FIGS. 6a-6c,
is precluded by the obstacle presented by the set fastener acting
against the sloping wall of the expanded mandrel.
The third stroke of this embodiment involves releasing the trigger,
causing a forward stroke as the spring again drives the piston
forward in chamber 16 once the air starts escaping from port 106.
The effect of this forward stroke is to drive collar 34' forward in
cylinder 40' with the key members 166 moving along the keyway 168
from points B to points designated C, which drives the collar to
the front of the cylinder, unexpanding the mandrel.
This prepares the mandrel assembly for withdrawal through the rivet
back into the tool. This is the effect of the fourth stroke of the
cycle, which is caused by again depressing the trigger 94 and
driving the piston 146 backwardly. The initial effect of this
backward stroke is not to expand the mandrel, since the collar 34'
moves backwardly in cylinder 40' only slightly. This is due to the
key members moving in the keyways only from the points C to the
points designated points D. Thus, the backward movement of the
collar 34' with respect to the cylinder 40' is halted near the
front of the cylinder and then the entire mandrel assembly is
withdrawn through the rivet back into the housing 74 as the piston
travels back towards the back wall of chamber 78, readying the
system for the next cycle on the next forward stroke of the
piston.
It will be noted that in this embodiment, there is a provision for
the collar to move backward in the cylinder a small amount, seen
most clearly in FIGS. 9A and 9C, without expanding the mandrel. The
length of this amount is equal to the longitudinal element of the
length of travel of the keys in the keyway portion C-D and is
provided so that the mandrel assembly will be unexpanded during
stroke four so that it may come back freely through the rivet.
The advantages of this four stroke system are manifest. The eyelet
type fastener and others like it having a hole of constant diameter
are the most desireable to use in many applications due to their
strength and low cost. Heretofore it has been particularly costly
and difficult to set these type of rivets in blind situations and
impossible to set them with a strong set. Now, with the modified
collar and cylinder shown in FIGS. 7 and 8, the semi-automatic tool
of FIGS. 3-5 may be used to set this type of fastener. As described
hereinabove, the hand fed tool of FIG. 1 is also operable to set
the eyelet fastener, using a two stroke cycle.
This embodiment also permits the employment of special blind
fasteners, such as those shown in FIGS. 10-12. Referring to FIG.
10, a water tight fastener 170 comprises the usual head portion 172
and a barrel portion 174 that is closed at the far end thereof and
includes a crimped portion 176. The inner diameter of the crimp 176
is selected such that the unexpanded mandrel of the embodiment
shown in FIGS. 7, 8 and 9A-9D can pass therethrough. Thus, when the
mandrel is expanded and withdrawn, the sleeve segments 42 will
engage the far side of the crimp and set the rivet against the far
side of the work.
With reference to FIG. 11, this embodiment of the invention makes a
threaded blind rivet possible. One such rivet, designated 180,
includes the usual head portion 182 and a barrel portion 184 that
includes a threaded portion 186 and an unthreaded portion 188. The
expanded mandrel will set the unthreaded portion, leaving the
threaded portion intact since the inside diameter of the threading
is selected to permit the unexpanded mandrel to freely pass
therethrough.
FIG. 12 depicts a crimped, threaded rivet 190 that combines the
features of rivets 170 and 180 in that it includes a crimped
portion 192 and a threaded portion 194, resulting in a water-tight,
threaded rivet.
With reference to FIG. 13, the fastening tool shown in FIGS. 3-5
can be mounted in a fixture 200 including a fastening tool housing
202 that corresponds to housing 74 of the embodiment of FIGS. 3-5.
The fixture includes a Syntron type feed 204 to the escapement
mechanism 84 (not specifically shown) in the fixture housing
wherein fasteners are fed to the mandrel assembly mounted in the
housing for reciprocal motion out the fixture nose 206, identical
to nose 92, in the same fashion as the semiautomatic tool shown in
FIGS. 3-5. An anvil 208 having an aperture therein mounted for up
and down movement on a support 210 that is raised and lowered by an
air cylinder 212.
The operation of air cylinder 212 is in timed relationship with the
mandrel assembly drive such that the anvil is raised on the
downstroke of the mandrel assembly, wherein the fastener on the
mandrel assembly is either placed in a prepared hole in the
material, or a hole in the material is made for the fastener by the
mandrel conical portion 32 on the downstroke of the mandrel. the
rearward stroke of the mandrel assembly then sets the fastener as
set forth hereinabove in connection with the embodiment shown in
FIGS. 3-5.
This fixture is most suited to the fastening of two pieces of
cloth, of cloth to plastic, or of two pieces of like soft material,
and thus the mandrel expanding sleeve embodiment of FIG. 2b would
be most suited thereto.
Having now fully set forth both structure and operation of
preferred embodiments of the concept underlying the present
invention, it may be that various other embodiments as well as
certain variations and modifications of the embodiments herein
shown and described will occur to those skilled in the art upon
becoming familiar with said underlying concept. For example, it
will be apparent to one skilled in the art that the mandrel
assembly 10 utilized in all of the embodiments described
hereinabove is fabricated of a hard material having a high tensile
strength such as maraging steel, such that it is operable to set
many tens of thousands of fasteners, which are, by their nature,
fabricated of relatively soft deformable materials.
This difference in the relative hardness of the mandrel assembly
and the fasteners coupled with the power of the various drive
mechanisms disclosed provides a capability to the invention of
setting a fastener without passing the mandrel assembly completely
through the aperture therein.
The mandrel need only be inserted into the fastener to a position
where the enlarged head thereof is past the portion of the fastener
barrel that is located interior of the work. The subsequent
expansion of the mandrel distends the barrel of the fastener and,
when the expanded mandrel is driven toward the anvil, the barrel of
the fastener distends back to the work, setting the fastener.
When the method of the invention is practiced in this manner, it
can be used to set fasteners having a substantially uniform
cylindrical barrel with a closed end to provide an inexpensive
weatherproof fastening.
It will be evident that in the practice of this last named method
that if the mandrel assembly had initially been precisely located
with respect to the work such that the barrel of the fastener is
distended back to the work by the initial expansion of the
assembly, the step of driving the assembly toward the anvil is
omitted since a set fastener blocks rearward movement of the
mandrel assembly.
In a modification of this last named method, the mandrel assembly
can be inserted into the fastener aperture at the barrel end
thereof and expanded to set the fastener.
Furthermore, several alternative constructions and modes of
expanding the mandrel assembly 10 are readily suggested to one
skilled in the art. For example, referring to FIGS. 2c-2e, it will
be apparent that the expansion of the effective cross-section of
the mandrel assembly could be effected by the reverse of the
elements shown. More specifically, the expansion of the effective
cross-section of the mandrel assembly shown in FIGS. 2c-2e could be
effected by utilizing a triangular shaft 24" without the enlarged
head portions 30 and 32, lengthening the segments 42" so that they
protrude in front of the end of the shaft 24" and thickening the
protruding ends. The thickened segment end portions are in
cross-section a segment 42" such as shown in FIGS. 2c-2e with a
rectangular portion contiguous to the secant side thereof, the
height of the rectangle increasing from zero at the position on the
segments where the leading end of the shaft is positioned in the
unexpanded mode to a maximum at the tips thereof.
With this arrangement, assuming the drive mechanism has also been
reversed to withdraw the segments initially rather than the shaft,
the segments are withdrawn to expand the mandrel and then the
assembly as a whole is driven to the rear. The expansion of the
mandrel is caused by the thickened segment end portions riding up
onto the shaft, the effect being to move the circular sides of the
segments outwardly to set the fastener.
These and all other such embodiments, variations, and modifications
that incorporate the spirit of the invention and depend upon its
underlying concept are consequently to be considered as within the
scope of the claims appended herebelow, unless the claims by their
language expressly state otherwise.
* * * * *