U.S. patent number 3,654,792 [Application Number 04/844,894] was granted by the patent office on 1972-04-11 for apparatus and method for installing blind fasteners.
This patent grant is currently assigned to Briles Manufacturing. Invention is credited to Daniel R. Mead.
United States Patent |
3,654,792 |
Mead |
April 11, 1972 |
APPARATUS AND METHOD FOR INSTALLING BLIND FASTENERS
Abstract
An automatically sequencing, hydraulically powered pre-entry
pull-up tool for upsetting blind fastener sleeves on the blind side
of a structure, and a novel sequencing method employed by said tool
to assure complete and uniform fastener upsetting. The tool
includes a hand gun having a protruding threaded mandrel insertable
into a blind fastener sleeve to be upset, the mandrel rotating in
one direction to engage with the sleeve, axially retracting to pull
up and upset the sleeve, and then rotating in the opposite
direction to disengage from the sleeve, these three steps being
hydraulically powered in the hand gun by hydraulic power from a
remote source, and being electrically controlled. According to the
method of the disclosure uniform upsetting is assured by effecting
the automatic shifting from stage to stage of the operation by
sensing back pressure in the hydraulic system.
Inventors: |
Mead; Daniel R. (Hawthorne,
CA) |
Assignee: |
Briles Manufacturing (El
Segundo, CA)
|
Family
ID: |
25293898 |
Appl.
No.: |
04/844,894 |
Filed: |
July 25, 1969 |
Current U.S.
Class: |
72/391.8;
29/243.524; 72/114 |
Current CPC
Class: |
B25B
27/0014 (20130101); B21J 15/105 (20130101); Y10T
29/53743 (20150115) |
Current International
Class: |
B21J
15/04 (20060101); B21J 15/06 (20060101); B25B
27/00 (20060101); B21J 15/00 (20060101); B21d
009/05 () |
Field of
Search: |
;72/391,114,453 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lanham; Charles W.
Assistant Examiner: Crosby; Gene P.
Claims
I claim:
1. A pre-entry pull-up tool for upsetting internally threaded blind
fastener sleeves, which comprises a hand gun having a protruding,
threaded mandrel that is insertable into a blind fastener sleeve to
be upset, reversible rotary drive means in the gun connected to the
mandrel for driving the mandrel in first and second directions of
rotation, translational drive means in the gun connected to the
mandrel for axially driving the mandrel inwardly of the gun, a
source of motive power operatively connected to said rotary and
translational drive means, automatically sequencing control circuit
means connected to said power source for (1) driving the mandrel in
said first direction of rotation in a screw-in mode of operation of
the tool to effect threaded engagement of the mandrel in a blind
fastener sleeve, (2) driving the mandrel axially in a pull-up mode
of operation to upset the sleeve, and (3 ) driving the mandrel in
said second direction of rotation in a screw-out mode of operation
to disengage the mandrel from the sleeve, and manually actuable
means operatively connected to said control circuit means for
initiating the automatic sequencing operation thereof.
2. A pre-entry pull-up tool as defined in claim 1, wherein said
power source is remote from said hand gun, and a flexible power
transmitting connection between said power source and said hand
gun.
3. A pre-entry pull-up tool as defined in claim 1, wherein said
control circuit means includes electrical switch means on the hand
gun and connected to said manually actuable means for initiating
the operation thereof.
4. A pre-entry pull-up tool as defined in claim 1, wherein said
rotary drive means and said translational drive means are
hydraulically actuated, and said power source includes a hydraulic
fluid pressure system hydraulically connected to said rotary drive
means and to said translational drive means.
5. A pre-entry pull-up tool as defined in claim 4, wherein said
hydraulic system is pneumatically energized.
6. A pre-entry pull-up tool for upsetting internally threaded blind
fastener sleeves, which comprises a hand gun having a protruding
threaded mandrel that is insertable into a blind fastener sleeve to
be upset, reversible rotary drive means in the gun connected to the
mandrel for driving the mandrel in first and second directions of
rotation, translational drive means in the gun connected to the
mandrel for axially driving the mandrel inwardly of the gun, a
source of motive power operatively connected to said rotary and
translational drive means, and automatically sequencing control
circuit means connected to said power source for (1) driving the
mandrel in said first direction of rotation in a screw-in mode of
operation of the tool to effect threaded engagement of the mandrel
in a blind fastener sleeve, (2) driving the mandrel axially in a
pull-up mode of operation to upset the sleeve, and (3) driving the
mandrel in said second direction of rotation in a screw-out mode of
mode of operation to disengage the mandrel from the sleeve, said
automatically sequencing control circuit means including sensing
means responsive to increased torque load on said mandrel for
initiating the automatic sequencing step from said screw-in mode of
operation to said pull-up mode
of operation. 6. A pre-entry pull-up tool as defined in claim 6,
wherein said rotary drive means is a motor in the gun, and said
sensing means is
responsive to substantially a stall condition of said motor. 8. A
pre-entry pull-up tool as defined in claim 7, wherein said motor is
hydraulically driven, said power source including a hydraulic fluid
pressure system hydraulically connected to said motor, and said
sensing means being responsive to a hydraulic fluid pressure
increase in said
hydraulic fluid pressure system. 9. A pre-entry pull-up tool for
upsetting internally threaded blind fastener sleeves, which
comprises a hand gun having a protruding, threaded mandrel that is
insertable into a blind fastener sleeve to be upset, reversible
rotary drive means in the gun connected to the mandrel for driving
the mandrel in first and second directions of rotation,
translational drive means in the gun connected to the mandrel for
axially driving the mandrel inwardly of the gun, a source of motive
power operatively connected to said rotary and translational drive
means, and automatically sequencing control circuit means connected
to said power source for (1) driving the mandrel in said first
direction of rotation in a screw-in mode of operation of the tool
to effect threaded engagement of the mandrel in a blind fastener
sleeve, (2) driving the mandrel axially in a pull-up mode of
operation to upset the sleeve, and (3 ) driving the mandrel in said
second direction of rotation in a screw-out mode of operation to
disengage the mandrel from the sleeve, said automatically
sequencing control circuit means including sensing means responsive
to increased pulling load on the mandrel for initiating the
automatic sequencing step from said pull-up mode of operation to
said
screw-out mode of operation. 10. A pre-entry pull-up tool as
defined in claim 9, wherein said translational drive means is
hydraulically driven, said power source including a hydraulic fluid
pressure system hydraulically connected to said translational drive
means, and said sensing means being responsive to a hydraulic fluid
pressure increase in
said hydraulic fluid pressure system. 11. A pre-entry pull-up tool
for upsetting internally threaded blind fastener sleeves, which
comprises a hand gun having a protruding, threaded mandrel that is
insertable into a blind fastener sleeve to be upset, reversible
rotary drive means in the gun connected to the mandrel for driving
the mandrel in first and second directions of rotation,
translational drive means in the gun connected to the mandrel for
axially driving the mandrel inwardly of the gun, a source of motive
power operatively connected to said rotary and translational drive
means, and automatically sequencing control circuit means connected
to said power source for (1) driving the mandrel in said first
direction of rotation in a screw-in mode of operation of the tool
to effect threaded engagement of the mandrel in a blind fastener
sleeve, (2) driving the mandrel axially in a pull-up mode or
operation to upset the sleeve, and (3) driving the mandrel in said
second direction of rotation in a screw-out mode of operation to
disengage the mandrel from the sleeve, said rotary drive means and
said translational drive means both being hydraulically actuated,
said power source including a hydraulic fluid pressure system
hydraulically connected through a first hydraulic connection to
said rotary drive means and through a second hydraulic connection
to said translational drive means, first sensing means associated
with said first hydraulic connection and responsive to a hydraulic
fluid pressure increase in said first hydraulic connection for
initiating the automatic sequencing step from said screw-in mode of
operation to said pull-up mode of operation, and second sensing
means associated with said second hydraulic connection and
responsive to a hydraulic fluid pressure increase in said second
hydraulic connection for initiating the automatic sequencing step
from said pull-up mode of
operation to said screw-out mode of operation. 12. A pre-entry
pull-up tool for upsetting internally threaded blind fastener
sleeves, which comprises a hand gun having a protruding, threaded
mandrel that is insertable into a blind fastener sleeve to be
upset, reversible rotary drive means in the gun connected to the
mandrel for driving the mandrel in first and second directions of
rotation, translational drive means in the gun connected to the
mandrel for axially driving the mandrel inwardly of the gun, a
source of motive power operatively connected to said rotary and
translational drive means, and automatically sequencing control
circuit means connected to said power source for (1) driving the
mandrel in said first direction of rotation in a screw-in mode of
operation of the tool to effect threaded engagement of the mandrel
in a blind fastener sleeve, (2) driving the mandrel axially in a
pull-up mode of operation to upset the sleeve, and (3) driving the
mandrel in said second direction of rotation in a screw-out mode of
operation to disengage the mandrel from the sleeve, said gun
including a body having front and rear ends, said mandrel
projecting forwardly from said body, and an anvil mounted on the
front end of the body, said anvil having an aperture therethrough
through which said mandrel extends, the anvil being engageable
against the exposed end of a blind fastener sleeve into which the
mandrel is inserted, said automatically sequencing control circuit
means including sensing means responsive to increased torque load
on the said mandrel for initiating the automatic sequencing step
from the said screw-in mode of operation to said pull-up mode of
operation, such increased torque load resulting from further
threaded engagement of the mandrel into a blind fastener sleeve
after said anvil is seated against the exposed end to the sleeve.
13. A pre-entry pull-up tool as defined in claim 12, wherein said
anvil is adjustable on said body relative to the axis of the
mandrel for adjusting the relative axial positions of the mandrel
threads and the anvil to
accommodate blind fastener sleeves of different lengths. 14. A
pre-entry pull-up tool for upsetting internally threaded blind
fastener sleeves, which comprises a hand gun having a protruding,
threaded mandrel that is insertable into a blind fastener sleeve to
be upset, reversible rotary drive means in the gun connected to the
mandrel for driving the mandrel in first and second directions of
rotation, translational drive means in the gun connected to the
mandrel for axially driving the mandrel inwardly of the gun, a
source of motive power operatively connected to said rotary and
translational drive means, and automatically sequencing control
circuit means connected to said power source for (1) driving the
mandrel in said first direction of rotation in a screw-in mode of
operation of the tool to effect threaded engagement of the mandrel
in a blind fastener sleeve, (2) driving the mandrel axially in a
pull-up mode of operation to upset the sleeve, and (3) driving the
mandrel in said second direction of rotation in a screw-out mode of
operation to disengage the mandrel from the sleeve, said rotary
drive means being a reversible hydraulically driven motor, and said
power source including a hydraulic fluid system hydraulically
connected to said motor, said hydraulic system including a fluid
reservoir, a hydraulic pump having an input connected to the
reservoir and having an output, a hydraulic loop circuit having
first and second ends and having said motor therein arranged so
that fluid flow from said first end toward said second ends
operates the motor to drive the mandrel in said first direction of
rotation, and fluid flow in the opposite direction in said loop
operates the motor to drive the mandrel in said second direction of
rotation, and valve means connected to said reservoir, to said
pump, and to both ends of said loop circuit, said valve means being
shiftable between a first position wherein it connects said first
end of the loop circuit to said pump output and said second end of
the loop circuit to said reservoir to cause the mandrel to be
driven in said first direction of rotation, and a second position
wherein it connects said second end of the loop circuit to said
pump output and said first end of the loop circuit to said
reservoir to cause the mandrel to be driven in
said second direction of rotation. 15. A pre-entry pull-up tool as
defined in claim 14, wherein said valve means is also shiftable to
a third, shut-off position wherein it blocks said pump output from
both ends of said loop circuit, and pressure-responsive means
connected to said loop circuit between said first end thereof and
said motor, said pressure responsive means being operatively
connected to said valve means to shift said valve means from its
said first position to its said third position in response to a
substantial pressure increase in said loop circuit caused
by substantially a stall condition of said motor. 16. A pre-entry
pull-up tool as defined in claim 15, which includes solenoid means
connected to said valve means for shifting said valve means between
its said positions, said pressure responsive means comprising a
pressure which electrically
connected to said solenoid means. 17. A pre-entry pull-up tool as
defined in claim 14, wherein said translational means is
hydraulically driven, said hydraulic fluid system including a
second hydraulic circuit having second valve means therein, said
second circuit including fluid connections between said second
valve means and said reservoir and pump respectively, and a fluid
conduit between said second valve means and said translational
drive means, said second valve means being shiftable between a
first position wherein it connects said conduit to said reservoir
to allow fluid drainage from said translational drive means so that
the latter is inoperative, and a second position wherein it
connects said conduit to said pump output to drive the mandrel
axially in said pull-up
mode of operation. 18. A pre-entry pull-up tool as defined in claim
17, which includes pressure-responsive means connected to said
conduit and operatively connected to said second valve means to
shift said second valve means from its said second position to its
said first position in response to a substantial pressure increase
in said conduit caused by a
substantial increase in the pulling load on the mandrel. 19. A
pre-entry pull-up tool as defined is claim 17, wherein said
first-mentioned valve means is also shiftable to a third, shut-off
position wherein it blocks said pump output from both ends of said
loop circuit, pressure-responsive means connected to said loop
circuit between said first end thereof and said motor, said
pressure-responsive means being operatively connected to said
first-mentioned valve means and to said second valve means to shift
said first-mentioned valve means from its said first position to
its said third position and to shift said second valve means from
its said first position to its said second position in a response
to a substantial pressure increase in said loop circuit caused by
substantially a stall condition of said motor, whereby the response
of said pressure-responsive means to substantially a stall
condition of said motor causes automatic shifting of said tool from
said screw-in mode of operation to said pull-up
mode of operation. 20. A pre-entry pull-up tool as defined in claim
19, which includes second pressure-responsive means connected to
said conduit and operatively connected to said second valve means
and to said first-mentioned valve means to shift said second valve
means from its said second position to its said first position and
to shift said first-mentioned valve means from its said third
position to its said second position in response to a substantial
pressure increase in said conduit caused by a substantial increase
and the pulling load on the mandrel, whereby the response of said
second pressure-responsive means to a substantial increase in the
pulling load on the mandrel causes automatic shifting of said tool
from said pull-up mode of operation to said
screw-out mode of operation. 21. A pre-entry pull-up tool for
upsetting internally threaded blind fastener sleeves, which
comprises a hand gun having a protruding, threaded mandrel that is
insertable into a blind fastener sleeve to be upset, reversible
rotary drive means in the gun connected to the mandrel for driving
the mandrel in first and second directions of rotation,
translational drive means in the gun connected to the mandrel for
axially driving the mandrel inwardly of the gun, a source of motive
power operatively connected to said rotary and translational drive
means, automatically sequencing control circuit means connected to
said power source for (1) driving a mandrel in said first direction
of rotation in a screw-in mode of operation of the tool to effect
threaded engagement of the mandrel in a blind fastener sleeve, (2)
driving the mandrel axially in a pull-up mode of operation to upset
the sleeve, and (3) driving the mandrel in said second direction of
rotation in a screw-out mode of operation to disengage the mandrel
from the sleeve, and manually operable selector means operatively
connected to said control circuit means and movable between a first
position wherein said control circuit means causes automatic
sequencing of said tool through said screw-in, pull-up, and
screw-out modes of operation, and a second position wherein said
control circuit means causes said tool to operate only in
said screw-out mode of operation. 22. The method of upsetting an
internally threaded blind fastener sleeve which comprises the steps
of inserting a threaded mandrel into said sleeve, rotating said
mandrel in a first direction of rotation for screwing the mandrel
into the sleeve, sensing the torque load on the mandrel during said
rotation thereof, terminating said rotation of the mandrel and
initiating translational pull-up movement of the mandrel to upset
the sleeve in response to a substantial increase in said torque
load, sensing the pulling load on the mandrel during said pull-up
movement, and terminating said axial pull-up movement and
initiating rotation of the mandrel in a second direction of
rotation for screwing the mandrel out of the sleeve in response to
a
substantial increase in said pulling load. 23. The method of
upsetting an internally threaded blind fastener sleeve which
comprises the steps of inserting a threaded mandrel into said
sleeve, rotating said mandrel in a first direction of rotation for
screwing the mandrel into the sleeve, sensing the torque load on
the mandrel during the said rotation thereof, terminating said
rotation of the mandrel and initiating translational pull-up
movement of the mandrel to upset the sleeve in response to a
substantial increase in said torque load, sensing the pulling load
on the mandrel during said pull-up movement and initiating rotation
of the mandrel in a second direction of rotation for screwing the
mandrel out of the sleeve in response to a substantial increase in
said pulling load, the rotational and translational movements of
the mandrel being effected by a hydraulic power system, the torque
and pulling loads on the mandrel being sensed by sensing back
pressures in the hydraulic power system.
Description
BACKGROUND OF THE INVENTION
The present invention relates to blind fasteners, i.e., bolt type
fasteners which are capable of being installed from one side only
of a structure, and it relates more particularly to apparatus and
methods for installing blind fasteners efficiently and rapidly, and
with assurance that each of a series of blind fasteners will be
fully expanded on the blind side of the workpiece and will be
uniformly pulled up in the axial direction.
Large numbers of blind fasteners are required in such highly
stressed structures as modern aircraft structures, in regions
thereof where access to one side of a structural joint in
difficult.
Most of such blind fasteners which are employed in modern
high-speed aircraft embody a sleeve portion which is inserted from
the access side of the structure into a bore through the structure,
the sleeve having a head at one end adapted to seat on the access
side of the structure, an internally threaded pull-up portion
adjacent the other end thereof which is engageable by a threaded
mandrel insertable through the sleeve from the access side, and an
intermediate deformable section adapted to buckle outwardly in
response to pull-up movement of the mandrel. In this way, the
structure is axially clamped between the head part of the sleeve on
the access side and the outwardly buckled deformable section of the
sleeve which functions as a nut. While some blind fasteners include
only such a sleeve, in most cases the sleeve is secured against
radial inward deformation under tension, and is provided with
additional shear strength, by insertion of a core pin or bolt into
the central passage of the sleeve after the sleeve has been
installed in the structure as aforesaid.
A major problem in the installation of such blind fasteners is that
the proper amount of axial take-up and radial expansion of the
sleeve on the blind side of the structure is critical in achieving
the fully rated strength of the fastened joint, but at the same
time the part of the fastener which is thus taken up and expanded
is on the blind side of the structure and is inaccessible to visual
inspection to assure that it has in fact been taken up and expanded
to the correct extent. Conventional apparatus and methods for
pulling up and expanding blind fastener sleeves rely substantially
completely on a determination by the installing operator as to the
extent of engagement of the pull-up mandrel with the internally
threaded pull-up portion of the sleeve, and the amount of axial
movement of the mandrel that is applied to expand the deformable
section of the sleeve and provide axial clamp-up force. One type of
hydraulically powered tool currently widely used for this purpose
has a cycle of operation for installing each blind fastener sleeve
that includes three separate manual controls which must be
sequentially actuated in order to complete an installation. A first
manual control button is depressed to cause the pull-up mandrel to
rotate in a clockwise direction for engagement with the internally
threaded pull-up portion of the sleeve on the blind side of the
structure. The extent of threaded engagement of the mandrel with
the sleeve depends upon how long the appropriate button is
depressed, and is accordingly variable according to operator
judgement. The extent of threaded engagement of the mandrel with
the sleeve is made further uncertain with such equipment by
pulsating hydraulic power from a reciprocating type hydraulic pump,
with the result that torque is applied intermittently to the
threaded mandrel. Then, when the mandrel is thus threadedly engaged
with the sleeve and the first button is released, a second button
is manually depressed to produce pull-up force on the mandrel for
buckling the deformable section of the sleeve, this pull-up force
being released only upon release of the second actuating button.
The final step with such conventional equipment is to provide
anticlockwise rotation of the mandrel to unscrew the mandrel from
the sleeve either by depressing a third button or by flipping a
reversing lever and depressing the first button again.
With conventional equipment of this type, the extent of threaded
engagement of the mandrel in the sleeve is uncertain, and
consequently the extent of axial take-up is not fully predictable
and reliable. If the operator should happen to let up too soon on
the first button so that the threaded engagement is inadequate
withstand the stresses of the second stage, then the threads can be
torn out in the second stage and the fastener left in only
partially assembled condition. Also, it is not infrequent that such
fasteners are damaged by the operator inadvertently depressing the
wrong button. Additionally, expansion and pull-up may be left
incomplete if the operator should release the second button too
soon.
SUMMARY OF THE INVENTION
In view of these and other problems in the art, it is an object of
the present invention to provide a novel hydraulically powered
pre-entry pull-up tool for expanding blind fastener sleeves on the
blind side of a structure and axially clamping the sleeves, wherein
the extent of each of the critical operative steps is automatically
determined by the tool rather than manually so as to assure uniform
installation characteristics of a series of similar blind fastener
sleeves.
Accordingly, it is a more particular object of the invention to
provide a hydraulically powered pre-entry pull-up tool of the
character described wherein the extent of threaded engagement of
the pull-up mandrel of the tool into the internally threaded part
of the blind fastener sleeve is determined by sensing a
predetermined reaction torque on the mandrel. Similarly, it is a
more particular object of the invention to provide a tool of the
character described wherein the extent of axial pull-up of the
mandrel, and hence the extent of the axial upsetting movement and
pull-up force on the blind fastener sleeve, is determined by
sensing a predetermined axial reaction force on the mandrel.
Another object of the invention is to provide a hydraulically
powered apparatus of the character described for installing blind
fastener sleeves wherein the aforesaid predetermined reaction
torque and axial reaction force on the mandrel are determined in
the apparatus by sensing back pressures in the hydraulic
system.
A further object of the present invention is to provide apparatus
of the character described for installing blind fastener sleeves
which is hydraulically powered, with the hydraulic power means
electrically controlled so as to be automatically sequencing
between screw-in, take-up, and screw-out modes of operation.
A still further object of the invention is to provide apparatus of
the character described for installing blind fastener sleeves
wherein the operator simply manipulates a hand gun having a
protruding threaded mandrel that is insertable into each blind
fastener sleeve, and wherein the entire sequence of operation for
installing each blind fastener sleeve, including screw-in, pull-up,
and screw-out, is effected by actuating a single triggering device
on the hand gun which causes automatic electrical control of a
hydraulic power unit remote from the hand gun.
An additional object of the invention is to provide a novel method
of installing blind fastener sleeves of the character described,
wherein uniform upsetting and pull-up in a series of blind fastener
sleeves is assured by effecting the automatic shifting from stage
to stage of the operation in response to back pressure in the
hydraulic system at the completion of each stage of operation.
Other objects and advantages of the present invention will appear
during the course of the following part of the specification,
wherein the details of construction, mode of operation, and method
steps of a presently preferred embodiment are described with
reference to accompanying drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an axial, vertical section, with portions shown in
elevation, illustrating the hand gun forming a part of the present
invention.
FIG. 2 is a perspective view illustrating the mandrel portion of
the hand gun separated from the rest of the gun.
FIG. 3 is a fragmentary, plan view taken on the line 3--3 in FIG. 1
illustrating the bottom of the handle of the hand gun, and in
particular illustrating the hydraulic and electrical passages into
the hand gun.
FIG. 4 is a cross-sectional view taken on the line 4--4 FIG. 1
showing structural details in the forward portion of the gun.
FIG. 5 is a vertical sectional view taken on the line 5--5 in FIG.
1, with a portion thereof in elevation, showing further details of
the gun in the region of the handle and body portions thereof.
FIG. 6 is another vertical sectional view, partly in elevation,
taken on the line 6--6 in FIG. 1, also showing details of the
handle and body portions of the gun.
FIG. 7 is an enlarged, fragmentary, vertical section taken on the
line 7--7 in FIG. 1 showing details of the hydraulic motor in the
gun.
FIG. 8 is also an enlarged, fragmentary, vertical section, taken on
the line 8--8 in FIG. 1, illustrating a portion of the gun forward
of the motor.
FIG. 9 is an exploded perspective view illustrating a portion of
the body of the hand gun and illustrating the various parts of the
gun making up the hydraulic motor and the support and housing
structure therefor.
FIG. 10 is a fragmentary, vertical, axial, section, partly in
elevation, illustrating the forward part of the hand gun
operatively engaged in a blind fastener sleeve at the completion of
the screw-in phase of operation of the gun.
FIG. 11 is a view similar to the FIG. 10, but illustrating a
further portion of the tool in section, showing the pull-up phase
of operation of the gun.
FIG. 12 is a view similar to FIGS. 10 and 11, but illustrating the
screw-out phase of operation of the tool.
FIG. 13 is an enlarged, fragmentary, vertical section showing a
portion of the structure illustrated in FIG. 7, and illustrating
the screw-in phase of operation of the hydraulic motor in the hand
gun.
FIG. 14 is a view similar to FIG. 13, but illustrating the
screw-out phase of operation of the hydraulic motor in the hand
gun.
FIG. 15 is a fragmentary, axial, vertical section, partly in
elevation, similar to FIG. 10, but showing the forward portion of
the hand gun adjusted to accommodate a blind fastener sleeve which
is shorter than the blind fastener sleeve shown in FIG. 10.
FIG. -6 is a side elevational view, partly in section, illustrating
the remote power unit which provides the hydraulic driving power to
the hand gun, and is electrically controlled from the hand gun.
FIG. 17 is a horizontal section, partly in elevation, taken on the
line 17--17 in FIG. 16.
FIG. 18 is a front elevational view, partly in section, taken on
the line 18--18 in FIG. 16.
FIG. 19 is a vertical section, partly in elevation, taken on the
line 19--19 in FIG. 16.
FIG. 20 is a fragmentary side elevational view of the remote power
unit that is shown in FIGS. 16 to 19, taken on the line 20--20 in
FIG. 18.
FIG. 21 is a diagrammatic view showing both the bottom of the
handle of the hand gun as illustrated in FIG. 3 and a portion of
the front panel of the remote power unit as shown in FIG. 18, with
the hydraulic and electrical lines from the remote power unit to
the hand gun illustrated diagrammatically.
FIG. 22 is a diagram of the hydraulic system of the apparatus,
together with a pneumatic system employed to drive the hydraulic
system.
FIG. 23 is a diagram of the electrical system of the apparatus.
DETAILED DESCRIPTION
Referring to the drawings, and at first particularly to FIGS. 1
through 9 thereof, these figures illustrate the structure of the
hand gun portion of the apparatus, which is generally designated
10. The hand gun 10 includes a generally hollow body 12 having an
integrally formed handle 14 depending therefrom.
An annular nose piece 16 is threadedly engaged with the body 12 at
the front end thereof by threaded coupling 18, the nosepiece 16
having a rearwardly opening cylindrical chamber 20 in its rearward
portion, and tapering down to a forwardly projecting, externally
threaded, tubular forward portion 22.
The body 12 defines a cylindrical chamber 24 therein, which is
axially aligned with and somewhat larger than the nosepiece
cylinder 20, immediately to the rear of nosepiece 16. A piston 26
is slidably mounted within the body cylinder 24, the piston 26
having an integral forwardly extending tubular axial shaft portion
28 which extends into the nosepiece cylinder 20. The piston 26 is
forwardly biased so as to normally seat against the rearward
annular edge of the nosepiece 16 as illustrated in FIG. 1 by means
of a coil compression spring 30, the forward end of which is
engaged against the piston, and the rearward end of which is seated
in an annular recess 32 in body 12 immediately to the rear of
cylinder 24.
A spindle 34 is both rotatably and slidably mounted in the gun 10,
with a forward portion thereof extending coaxially into the tubular
forward portion 22 of nosepiece 16, and a rearward portion thereof
extending coaxially through the tubular piston shaft 28. The
spindle 34 has an enlarged, hollow rear end portion which projects
rearwardly from the piston 26 and serves as a drive coupler for
application of rotary power to the spindle. A snap ring 38 is
engaged in a groove 40 in the spindle immediately forward of the
tubular piston shaft 28, whereby the piston 26 and its integral
shaft 28 are axially secured on the spindle 34 between the rear
spindle enlargement 36 and the snap ring 38. In this manner, the
piston 26 and spindle 34 move as a single unit in the axial
direction. Accordingly, the piston spring 30 biases the spindle 34
toward its forwardmost position as illustrated in FIG. 1.
It will be noted that the spindle 34 is held in axially centered
position within the body 12 and nosepiece 16 by engagement of the
spindle in a constricted portion 42 of nosepiece 16, and by
engagement of the rearward portion of the spindle in the piston
assembly which in turn is centered by engagement of the piston in
the body cylinder 24.
An O-ring seal 44 is engaged between the body 12 and nosepiece 16
rearwardly of the threaded coupling 18 to prevent escape of
hydraulic field to the outside of the hand gun 10. Another O-ring
seal 46 is engaged between the constricted portion 42 of the
nosepiece and the spindle 34 so as to prevent escape of pressurized
hydraulic fluid forwardly into the threaded tubular portion of the
nosepiece. Escape of pressurized hydraulic fluid rearwardly past
the piston 26 is opposed by a third O-ring seal 48 engageable
between the piston and the body cylinder 24 in the form of a
conventional piston ring, and a fourth O-ring seal 50 engageable
between the piston 26 and the spindle 34.
The pull-up mandrel 52 of the tool has an enlarged rearward
connector portion 54 which is coupled to the forward end portion of
spindle 34 by means of a collet 56 which is threadedly connected to
the forward end portion of spindle 34 by means of a left-hand
threaded coupling. The mandrel 52 has a rearwardly projecting flat
key 58 which is engaged in a complementary key slot 60 in the front
end of spindle 34, whereby the spindle 34 and mandrel 52 will move
as a single unit both axially and rotationally in both directions
of rotation. The collet 56 has a cylindrical outer surface which is
both slidably and rotationally engaged in the cylindrical inner
surface of the tubular forward portion 22 of the nosepiece 16,
providing axially centering support for the forward end of the
spindle 34 and for the mandrel 52. The mandrel 52 is provided at
its forward end portion with right-hand threads 62, this threaded
portion being releasably threadedly engageable with complementary
internal threads in a blind fastener sleeve as described
hereinafter in detail.
A tubular anvil 64 is annularly disposed about the mandrel 52,
anvil 64 having a rearwardly extending, internally threaded skirt
portion 66 which is threadedly coupled over the externally threaded
tubular forward portion 22 of the nosepiece 16. Mandrel 52 is
freely rotatable and slidable relative to the anvil 64, and anvil
64 has a generally flat forward working face 68 which engages
against the blind fastener sleeve head during the screw-in and
pull-up phases of operation of the apparatus as will hereinafter be
described in detail.
Also threadedly engaged over the externally threaded tubular
forward portion 22 of nosepiece 16, immediately to the rear of the
anvil skirt portion 66, is a locking ring or nut 70 which serves to
lock the anvil axially relative to the nosepiece. In FIG. 1 the
anvil 64 is at its rearwardmost position on the nosepiece 16, which
leaves a maximum length of the mandrel 52 projecting forwardly from
the working face 68 of the anvil, to accommodate a relatively long
blind fastener sleeve. Forward adjustment of the anvil 64 on the
nosepiece 16, secured by means of the locking ring or nut 70, will
accommodate blind fastener sleeves of shorter lengths.
Rotary power is supplied to the spindle 34 by means of a
reversible, gear-type hydraulic motor mounted on the rear end of
the hand gun body 12, the motor being generally designated 72.
Motor 72 includes a power gear 74 and an idler gear 76 meshed with
the power gear 74, the gears 74 and 76 having standard involute
gear teeth. Respective integral shafts 78 and 80 extend from both
ends of the gears 74 and 76. The shaft 78 for power gear 74
includes a forwardly extending portion 82 of square cross section
which is engaged in a complementary square aperture 84 in the
enlarged coupler portion 36 of the spindle 34. The coupler portion
36 of the spindle has a cavity 86 extending axially forwardly of
the square aperture portion 84 to allow substantial rearward
sliding movement of the drive coupler 36 over the square shaft
portion 82 during the pull-up phase of operation of the tool, and
dampening of this relative axial movement between the coupler 36
and the square shaft portion 82 due to a close-fitting relationship
therebetween, and due to the presence of hydraulic fluid in the
cylinder 24, is avoided by providing bleeder passage means 88 which
extends radially outwardly from the cavity 86 to the outside of
drive coupler 36.
The motor gears 74 and 76 are rotatably mounted in respective
parallel, communicating, arcuate cavities 90 and 92 which extend
axially through a motor gear housing plate 94 of substantially the
same axial thickness as the length of the gears 74 and 76. Inside
and outside manifold plates 96 and 98, respectively, seat flush
against the front and rear surfaces of the motor gear housing plate
94, the manifold plates 96 and 98 each being provided with a pair
of bores that are coaxial with the respective gear cavities 90 and
92 in the housing plate 94, to provide journals for the respective
gear shifts 78 and 80.
The inside manifold plate 96 is adapted to seat flush against a
generally flat rearwardly facing surface 100 of body 12, while a
generally flat motor cover plate 102 is adapted to seat against the
rear surface of outside manifold plate 98.
The entire assembly consisting of motor gear housing plate 94 and
the gears 74 and 76 therein, the two manifold plates 96 and 98, and
the motor cover plate 102, is secured to the gun body 12 by means
of a plurality of screws 104 which extend through aligned apertures
in the plates 94, 96, 98 and 102, and threadedly engage in the rear
of body 12 as best seen in FIG. 1. Sealing rings 106 are engaged
between each pair of mating surfaces in this assembly radially
outwardly of the hydraulic motor gears 74 and 76 and shafts 78 and
80, to prevent the escape of hydraulic fluid through the
interfaces.
The hydraulic fluid passage system of the hand gun 10 includes
three inlet conduits which receive hydraulic fluid under pressure
from the remote power unit and one hydraulic fluid drain conduit.
Thus, referring in particular to FIGS. 1, 3, and 5, looking
forwardly from the rear of the gun as in FIG. 5, at the right-hand
side of the handle is a conduit 108 which is connected to the
remote power unit by a flexible hose to receive hydraulic actuating
fluid for the screw-in phase of mandrel operation. Similarly, fluid
conduit 110 in the left-hand side of the gun handle looking
forwardly as in FIG. 5 receives hydraulic actuating fluid from the
remote power unit through a suitable flexible hose for the
screw-out phase of mandrel operation. Centered between the sides of
the handle, and located forwardly of the conduits 108 and 110, is a
third conduit 112 which receives hydraulic actuating fluid from the
remote power unit through a suitable flexible hose for the pull-up
phase of mandrel operation. Finally, a drain conduit 114 is
centered between the sides of the handle to the rear of the
conduits 108 and 110, the conduit 114 being connected to the remote
power unit through a fourth flexible hose to return hydraulic fluid
from the gun back to the power unit.
The fluid conduits 108 and 110 extend upwardly through the handle
14 and then rearwardly, generally parallel to each other, through
the body 12 of the gun, opening into respective upwardly extending
grooves 116 and 118 in the rear surface 100 of body 12. The upper
ends of grooves 116 and 118 communicate with respective ports 120
and 122 which extend in the axial direction through inside manifold
plate 96 and open in horizontally spaced relationship to the gear
cavities 90 and 92 proximate the constriction where the cavities 90
and 92 come together; i.e., the ports 120 and 122 communicate with
the gear cavities 90 and 92 proximate the horizontal centerline
therebetween. As best shown in FIG. 7, the ports 120 and 122 are
spaced apart slightly more than the thickness of a single tooth of
either of the gears 74 and 76, and by providing a close tolerance
fit between the gears 74 and 76 there will always be substantially
a one-tooth seal between the ports 120 ad 122. A close tolerance
fit is also provided between the outer periphery of power gear 74
and its gear cavity 90, and between the periphery of the idler gear
76 and its gear cavity 92. In this manner, the gears 74 and 76
provide a labyrinth type seal in their respective cavities 90 and
92 and the pressure falls off in a steep gradient from the parts
120 and 122 peripherally outwardly about the cavities 90 and 92.
With this arrangement, the gear motor is highly efficient, and it
is unnecessary to provide conventional bleed passages diametrically
through the gears.
When fluid under pressure is supplied to the fluid conduit 108 in
the handle 14, it passes upwardly through conduit 108 into groove
116 in surface 100 of the body and thence through the respective
port 120 into the region where the gear cavities 90 and 92 join.
Then, the fluid flows to the left as viewed in FIGS. 7 and 13, in
the direction of the arrows in FIG. 13, displacing the meshed gear
teeth to the left the fluid then discharging out through port 122,
groove 118 and thence out of the hand gun portion of the tool
through the fluid conduit 110. Thus, fluid flowing in this
direction will cause the power gear 74 to rotate clockwise as
viewed in FIGS. 5, 7, 9, and 13. Correspondingly, the shaft 78 of
gear 74 will be rotated clockwise, and the square portion 82
thereof will cause the spindle 34 and the mandrel 52 to rotate in a
clockwise direction.
Conversely, when hydraulic fluid under pressure is introduced into
the hand gun through fluid conduit 110, it passes upwardly through
the handle and rearwardly through the body portion of conduit 110
into groove 118, from which it passes rearwardly through port 122,
and as indicated by the flow arrows in FIG. 14, flows to the right
in the region where the gear cavities 90 and 92 join, forcing the
meshing gear teeth to the right as viewed in FIG. 14. The fluid
then flows out through the port 120, groove 116 and fluid conduit
108. Thus, when fluid under pressure is introduced into the gun
through fluid conduit 110, it causes the power gear 74 to rotate in
an anticlockwise direction as viewed in FIGS. 5, 7, 9, and 14,
thereby rotating the power gear shaft 78 and its square forward
portion 82 anticlockwise, and correspondingly rotating the spindle
34 and mandrel 52 anticlockwise.
A small amount of the hydraulic fluid which is thus introduced into
the hand gun through the fluid conduits 108 and 110 will flow into
the journals for the gear shafts 78 and 80 so as to lubricate the
latter, from the gear cavities 90 and 92 adjacent the ends of the
gears 74 and 76.
Such of the hydraulic fluid as may seep into the interfaces between
rear body surface 100 and manifold plate 96 or between plates 96,
94, 98, and 102, from any source, as for example from the grooves
116 and 118, the ports 120 and 122, the gear shift journals, or the
gear cavities 90 and 92, will be prevented from escaping to the
outside of the hand gun by the sealing rings 106 as aforesaid, and
will be collected by a series of axially aligned leakage ports 124,
126, and 128, respective plates 98, 94, and 96, and fed to a
further leakage port 130 in the body 12 opening at rear surface 100
thereof, the final leakage port 130 extending forwardly into
communication with the annular recess 32 in the body 12, from which
such drainage fluid is enabled to flow out of the hand gun through
the drain conduit 114.
Hydraulic fluid under pressure introduced into the fluid conduit
112 passes upwardly through the handle 14 and thence forwardly in
the body 12 into the body cylinder 24 forwardly of piston ring 48,
thereby building up fluid pressure forward of the piston in the
chambers 24 and 20 and forcing the piston 26 rearwardly against the
forward biasing force of spring 30, thus moving spindle 34 and
mandrel 52 axially rearwardly in the hand gun relative to the anvil
64 Hydraulic fluid which may seep rearwardly past the piston ring
48 is simply collected in the cylindrical chamber 24 and annular
recess 32 to the rear of the piston, and drains out of the hand gun
through the drain conduit 114 which communicates at its upper end
with the cylindrical body chamber 24. Actually, hydraulic fluid
previously accummulated in the cylinder 24 and recess 32 from
bypassing the piston 26 and from leakage out of the hydraulic motor
72, is pumped out of the hand gun through drain conduit 114 each
time the piston 26 is driven rearwardly during a cycle of operation
of the tool.
Upon release of pressure of the hydraulic fluid in the conduit 112,
the spring 30 is enabled to return the piston 26, and consequently
the spindle 34 and mandrel 52, forwardly to the position shown in
FIG. 1, with excess fluid from chamber 20 in the nosepiece 16 and
from the cylindrical body chamber 24 forward of piston ring 48
simply flowing back out through the fluid conduit 112.
The hand gun 10 has a single finger-actuated switch button 132
thereon which projects forwardly from a trigger-shaped, concave
finger guide 134 projecting forwardly from the upper front portion
of the handle 14. The switch button 132 actuates a normally open
electrical switch 136, the two contacts of which are electrically
connected to a pair of wires 138 and 140 which, together with a
ground wire 142, constitute the electrical elements of an
electrical cable 144 that extends from the hand gun 10 to the
remote power source. Depressing the switch button 132 to close
switch 136 completes an electrical circuit which causes the hand
gun 10 to hydraulically drive the mandrel 52 through a complete
cycle of operation.
Such a complete cycle of operation is illustrated in the sequence
of FIGS 10, 11, and 12 of the drawings which show the installation
of a blind fastener sleeve generally designated 146 in a structure
generally designated 148 comprising a pair of overlapping panels
150 and 152. The exposed side 154 of panel 150 shall be considered
to be the access side of the structure 148, while the exposed side
156 of the panel 152 shall be considered to be the blind side of
structure 148. The structure 148 has a bore 158 extending
therethrough from the access side 154 to the blind side 156, the
bore 158 having a counterbore 160 at the access end thereof to
receive the head 162 of the blind fastener sleeve where, as shown,
the blind fastener sleeve has a tapered type head.
The blind fastener sleeve 146 includes, in addition to the head
portion 162 thereof, a tubular body portion 164 which is generally
coextensive with the panel bore 158, but preferably terminates just
short of the blind side 156 of the structure, a thin-walled,
undercut, deformable section 166 which extends substantially beyond
the blind side 156 of the panel, and terminating in an internally
threaded pull-up portion 168 of the sleeve.
Installation of the blind fastener sleeve 146 in the structure 148
is accomplished by first inserting the fastener sleeve 146 into the
bore 158 from the access side 154 thereof until the sleeve head 162
seats in the counterbore 160. The hand gun 10 is then moved into
position so that its forwardly projecting mandrel 52 is generally
axially aligned with the sleeve 146, and the mandrel 52 is then
inserted through the sleeve 146 until the forward end of the
mandrel comes into contact with the threads in the pull-up portion
168 of the sleeve where that portion of the sleeve joins with the
deformable section 166 of the sleeve. Both as an aid to guiding the
forward end of the mandrel into the internally threaded pull-up
portion 168 of the sleeve, and to achieve the desired nut
configuration of the deformable section 166 of the sleeve after
pull-up, the deformable section 166 preferably includes a radially
inwardly tapering guide portion 170.
When the mandrel 52 is thus positioned, the operator simply presses
the finger switch button 132 and holds the button down until the
cycling has been completed. The first response to actuation of the
switch 136 in the gun will be provision by the remote power source
of hydraulic fluid under pressure to the fluid conduit 108 in the
handle of the gun, which will provide fluid pressure to the gear
motor 72 through port 120, thereby causing the mandrel 52 to be
rotated clockwise so that the threaded end portion 62 of mandrel 52
will automatically screw into the internally threaded pull-up
portion 168 of the blind fastener sleeve 146. This screw-in first
phase of operation of the hand gun will continue until the forward
working face 68 of anvil 64 and the sleeve head 162 are brought
tightly into engagement and the tubular column comprising the
nosepiece 16 and anvil 64 of the hand gun and the fastener sleeve
146 oppose further threaded engagement of the front end portion of
mandrel 52 into the pull-up portion 168 of the sleeve, at which
time the hydraulic motor 72 will stall, and corresponding back
pressure in the fluid conduit 108 will be sensed in the remote
power unit to automatically switch to the second phase of operation
of the apparatus.
The second phase is effected by introduction of hydraulic fluid
under pressure into the hand gun through fluid conduit 112, which
builds up fluid pressure forward of the piston 26, forcing the
piston 26 and hence the mandrel 52 rearwardly from the first-phase
stall position shown in FIG. 10 to cause the deformable section 166
of the blind fastener sleeve to buckle outwardly as shown in FIG.
11. This pull-up phase of the operation continues until the
deformable section 166 of the sleeve is collapsed to the point
where it applies sufficient force in opposition to further collapse
to build up back pressure of the hydraulic fluid in conduit 112 to
a predetermined pressure which is sensed in the remote power unit
and employed to automatically effect the shift from the second
phase of operation of the tool to the third phase of operation
which is illustrated in FIG. 12.
According to the third phase of operation, hydraulic fluid under
pressure is introduced into the hand gun through the fluid conduit
110, from which it is conducted to the hydraulic motor 72 through
port 122 to cause anticlockwise rotation of the mandrel 52, whereby
the threaded forward end portion 62 of the mandrel will screw out
of the internally threaded pull-up portion 168 of the blind
fastener sleeve. The three-phase installation cycle is complete
when the threaded forward end of the mandrel clears the threads of
the pull-up portion 168 of the blind fastener sleeve as illustrated
in FIG. 12, and at that point the finger switch button 132 can be
released by the operator to turn off the tool, and the mandrel
withdrawn from the fully installed blind fastener sleeve 146.
FIG. 15 is similar to FIG. 10, illustrating the mandrel 52 of the
tool fully threadedly engaged with the internally threaded pull-up
portion of a blind fastener sleeve at the termination of the first
or screw-in phase of operation of the tool. However, FIG. 15
differs from FIG. 10 by showing a shortened blind fastener sleeve
146a engaged through a bore 158a in structure 148a composed of a
pair of relatively thin panels 150a and 152a. Because of the
shortened length of the fastener sleeve 146a, if the tool were
adjusted as in FIG. 10, with the anvil 64 and locking ring 70 fully
rearwardly positioned on the tubular forward portion 22 of the
nosepiece, then the threaded front end portion 62 of mandrel 52
would screw too far through the internally threaded pull-up portion
168a of the fastener sleeve and there would be an insufficient
axial length of threaded engagement therebetween when the forward
face of the anvil 64 bottomed against the head of the fastener
sleeve at the completion of the first phase to assure that the
pull-up phase could be accomplished without damaging the fastener
sleeve. In fact, with an even shorter fastener sleeve than the
sleeve 146a illustrated in FIG. 15, the threaded forward end 62 of
the mandrel 52 might screw completely on through the threaded
pull-up portion of the fastener sleeve so that the hydraulic motor
stall-out to complete the first phase of operation might never
occur.
To accommodate such a shorter fastener sleeve 146a, all that is
necessary is to screw the anvil 64 forwardly on the tubular forward
portion 22 of the nosepiece a sufficient amount to assure full
threaded engagement of the threaded forward end 62 of the mandrel
in the internally threaded pull-up portion 168a of the fastener
sleeve, and then to lock the anvil 64 in this position by
tightening the locking ring 70 against the rearward end of the
anvil. The operation of the tool through the three phases,
screw-in, pull-up, and screw-out, will then be identical to the
operation described in connection with FIGS. 10, 11, and 12.
FIG. 22 diagrammatically illustrates the hydraulic system, which is
generally designated 172. Also illustrated in FIG. 22 is a
pneumatic power system, generally designated 174, which provides
the driving power to the hydraulic system. While the hydraulic pump
of the hydraulic system 172 can be powered by any conventional
prime mover, as for example an electric motor, the pneumatic power
system 174 is particularly desirable in that it does not produce
the sparks of an electric motor, and hence the explosion hazard of
an electric motor, and it utilizes readily available shop air which
is capable of bringing the hydraulic pump up to operational speed
with a minimum time lag.
Referring at first to the pneumatic power system 174, shop air is
supplied thereto through air inlet conduit 176, the air being
directed through a filter 178, a pressure regulator 180, and a
lubricator 182 to a normally closed solenoid-operated air valve
184. The lubricator 182 suspends a small amount of oil in the air
for lubrication of the air motor. A pressure gauge 186 is connected
between regulator 180 and valve 184 for monitoring the air pressure
that is supplied through valve 184 to the air motor. When the
solenoid-operated air valve 184 is energized and thereby moved from
the closed position that is illustrated to its open position, it
permits air to flow therethrough and thence through a flow control
valve 188, which adjustably meters the rate of air flow, to air
motor 190, which is silenced by a suitable muffler 192. The air
motor 190 drives the hydraulic pump 194 of the hydraulic system 172
through a suitable drive shaft connection 196.
The hydraulic pump 194 is energized in response to actuation of the
hand gun switch button 132 to close the normally open electrical
switch 136 located in the hand gun. Closure of switch 136 moves the
normally closed solenoid-operated air valve 184 to its open
position, thereby energizing the air motor 190 and consequently
hydraulic pump 194.
The hydraulic pump 194 furnishes hydraulic fluid under pressure
through a check valve 198 to fluid output conduit 200 which is
connected to directional control valve 202. Valve 202 is a
four-way, three-position, solenoid-operated valve having a normally
closed centered position as illustrated in FIG. 22, and being
movable to a first off-center position wherein the mandrel 52 of
the hand gun 10 is caused to rotate clockwise for the screw-in
operation, and alternatively to a second off-center position
wherein the mandrel 52 of the hand gun is caused to move
anticlockwise for the screw-out operation.
When the hand gun switch button 132 is initially depressed to close
the normally open electrical switch 136 in the hand gun, this not
only opens electrical switch 136 in the hand gun, this not only
opens the solenoid-operated air valve 184 as aforesaid to cause
energization of the hydraulic pump 194, but also energizes the
solenoid-operated directional control valve 202 to shift the valve
element thereof as diagrammatically illustrated in FIG. 22 to the
right, which connects the pump output conduit 200 to hydraulic line
204, and also connects hydraulic line 206 to a line 208 which
returns the hydraulic fluid to reservoir 210. The hydraulic system
is a recirculating one, the reservoir 210 being the source of the
hydraulic fluid for the hydraulic pump 194, which receives this
fluid through input conduit 212.
Hydraulic line 204 is connected through a speed control valve 214
and flexible hose 216 to the fluid conduit 108 that leads to one
side of the hydraulic motor 72 in hand gun 10. The fluid conduit
110 leading to the other side of the hydraulic motor 72 in the hand
gun is connected through flexible hose 218 to the hydraulic line
206.
Thus, in the initial mode of operation of the apparatus when the
gun switch 136 is closed by depressing the switch button 132, with
the hydraulic pump 194 energized and the directional control valve
202 in its first off-center position, to the right as illustrated
in FIG. 22, hydraulic fluid will pass from the pump 194 through
conduit 200 and valve 202 into the hydraulic line 204, and thence
through flexible hose 216 to the hand gun conduit 108 so as to
drive the hydraulic motor 72 in the hand gun clockwise to screw the
mandrel 52 into the pull-up portion of the blind fastener sleeve.
After driving the hydraulic motor, the fluid then returns to the
reservoir 210 through hand gun conduit 110, flexible hose 218,
hydraulic line 206, directional control valve 202 and hydraulic
return line 208.
A pressure switch 220 is operatively connected to the hydraulic
line 204, and when the hydraulic motor 72 stalls at the completion
of the screw-in mode, the back pressure increase in hydraulic line
204 corresponding to this stall condition of the hydraulic motor 72
causes actuation of pressure switch 220, which in turn causes
release of the directional control valve 202 back to its center
position as illustrated in FIG. 22, thus cutting of the connection
between conduit 200 and line 204 and thereby stopping the flow of
hydraulic fluid to the hydraulic motor 72. Simultaneously, such
actuation of the pressure switch 220 energizes a piston operating
valve 222 to shift it from its normal position as illustrated in
FIG. 22 to the right to its actuated position wherein it provides
hydraulic fluid under pressure from the pump 194 to the hand gun
cylinder 24 so as to force the hand gun piston 26 and the mandrel
52 rearwardly in the pull-up mode of operation of the tool. With
the piston operating valve 222 thus shifted to the right as
illustrated in FIG. 22 to effect the second or pull-up mode of
operation, hydraulic fluid pressure is conducted from the pump 194
through output conduit 200 and thence through hydraulic line 224
and valve 222 to a hydraulic line 226, flexible hose 228, and fluid
conduit 112 in the hand gun, to the cylinder 24 in the hand gun.
Drainage fluid from cylinder 24, and from hydraulic motor 72,
returns to the reservoir 210 through hand gun drain conduit 114 and
a further flexible hose 230.
An adjustable pressure switch 232 is operatively connected to the
hydraulic line 226, and when the back pressure in line 226 reaches
a predetermined value, as preset on the switch 232, the switch 232
is actuated so as to cause release of the piston operating valve
222 back to its normal position as illustrated in FIG. 22, wherein
the line 226 is disconnected from the pressure line 224 and line
226 is connected through valve 222 to a drain line 234. The drain
line 234 is connected to a hydraulic return line 208, whereby fluid
pressure from hand gun cylinder 24 is relieved through hand gun
conduit 112, flexible hose 228, line 226, valve 222, and lines 234
and 208 back to the reservoir 210, thereby allowing the hand gun
piston 26 to be returned to its initial, inoperative position.
Such closing of the adjustable pressure switch 232 in response to
back pressure in the hydraulic line 226 marks the completion of the
pull-up cycle of the tool, and also causes the directional control
valve 202 to shift to the left from its center position as
illustrated in FIG. 2 so as to provide fluid connection from the
pump output conduit 200 to hydraulic line 206, and also to connect
the hydraulic line 204 to the hydraulic return line 208. This
causes the hydraulic motor 72 in the hand gun to be driven
anticlockwise to produce the third mode of operation of the tool,
which is the screw-out mode wherein the mandrel 52 screws out of
the internally threaded portion of the blind fastener sleeve. In
this mode hydraulic fluid under pressure flows from the pump 194
through output conduit 200 and through directional control valve
202 to hydraulic line 206, from which the fluid passes through
flexible hose 218, and fluid conduit 110 in the hand gun to the
hydraulic motor 72. Fluid discharge from the motor 72 passes
through conduit 108 in the hand gun and thence through flexible
hose 216, hydraulic line 204, valve 202 and hydraulic return line
208 back to the reservoir 210. This third mode of operation
continues until the operator releases the hand gun switch button
132 to open the switch 136, which allows directional control valve
202 to return to its center position as illustrated in FIG. 22, and
which also releases the solenoid-operated air valve 184 in the
pneumatic power system 174, the air valve 184 thus being allowed to
return to its normally closed position as illustrated in FIG.
22.
Over-pressurization of the system is prevented by a relief valve
233 connected to output conduit 200. Slight pressure is maintained
in the system when it is inoperative by a back pressure valve 235
in return line 208.
Reference will now be made to FIG. 23 of the drawings, which
diagrammatically illustrates the electrical system employed in the
present invention for controlling the hydraulic and pneumatic
systems 172 and 174, respectively. Line current is fed through a
wall plug 236 to a pair of conductors 238 and 240, the conductor
238 being shown as a bus line for one side of the system. Line 240
has a fuse 242 therein, and leads to a selector switch generally
designated 244 which has three positions, an "off" position an
"auto" position for automatic cycling of the apparatus through the
screw-in, pull-up and unscrew modes of operation, and an "unscrew"
position which causes the screw-in and pull-up modes to be
bypassed, and allows the apparatus to operate only in the third or
unscrew mode. The "off" section 246 of the selector switch 244 is
an open contact section. The "auto" section 248 of switch 244 is an
open contact section. The "auto" section 248 of switch 244 has two
sets 250 and 252 of normally open contacts which are closed by
moving the selector switch 244 to the "auto" position. Similarly,
the "unscrew" section 254 of selector switch 244 has two sets 256
and 260 of normally open contacts which are closed by moving the
selector switch 244 to the "unscrew" position.
Assuming that the selector switch 244 is moved to the "auto"
position for normal automatic operation of the apparatus, this will
connect line conductor 240 through switch contacts 250 to a
conductor 262. An indicator light 264 connected between conductor
262 and the bus line 238 will become illuminated to indicate that
the apparatus is turned on. The energized conductor 262 is
connected through electrical connector 266 to one of the wires 138
leading to the normally open hand gun switch 136, the other hand
gun wire 140 leading through connector 266 to a conductor 268 that
is connected to one side of the solenoid-operated air valve 184,
the other side of which is connected to the bus line 238.
Solenoid-operated air valve 184 is closed in its normal,
unenergized condition, and since the hand gun switch 136 is
normally open as illustrated in FIG. 23, the air valve 184 will
remain closed until the hand gun switch 136 is closed by depressing
the switch button 132. When the hand gun switch 136 is closed, it
then completes an electrical circuit from the energized conductor
262 through the hand gun switch 136 to conductor 268 so as to
actuate the solenoid-operated air valve 184, thus opening the valve
184 and actuating the air motor 190 and consequently the hydraulic
pump 194.
When the selector switch 244 was initially moved to the "auto"
position, contacts 252 thereof were closed to provide electrical
connection between conductor 268 and a second bus line 270. Thus,
when the hand gun switch 136 is closed to commence operation of the
tool, and the conductor 268 is thereby energized as aforesaid, the
bus line 270 is likewise energized by the connection from conductor
268 through selector switch contacts 252. The directional control
valve 202 has two solenoid coils 202a and 202b diagrammatically
illustrated in FIG. 23. Energization of solenoid coil 202a causes
the directional control valve 202 to shift to the right from the
central position as illustrated in FIG. 22 for the screw-in phase
of operation of the tool, while energization of the solenoid coil
202b causes the directional control valve 202 to shift to the left
from the central position as illustrated in FIG. 22 for the unscrew
or final phase of operation of the tool. Energization of the bus
line 270 upon closure of the hand gun switch 136 as aforesaid
provides electric current to the solenoid coil 202a, thereby
initiating the screw-in phase of operation. One side of solenoid
coil 202a is electrically connected to the bus line 238. The other
side of coil 202a is connected to the other bus line 270 through
normally closed pressure switch 220.
Thus, closure of the hand gun switch 136 causes simultaneous
energization of the solenoid-operated air valve 184 and of solenoid
coil 202a of directional control valve 202, thereby simultaneously
turning on the hydraulic pump and directing the fluid flow
therefrom to turn the hydraulic motor 72 clockwise for the screw-in
phase of operation of the tool.
When the hydraulic motor 72 of the hand gun stalls at the end of
the screw-in mode of operation, the increased pressure in the
hydraulic line 204 causes the pressure switch 220 to momentarily
open, thereby releasing the solenoid coil 202a and allowing the
directional control valve 202 to shift back to the center position
as illustrated in FIG. 22. The momentary opening of pressure switch
220 also completes an electrical connection from bus line 270 to
the coil 272 of a relay generally designated 274 which has normally
open contact 276 and normally closed contact 278. Energization of
relay coil 272 opens the normally closed contact 278 which is in
the circuit to solenoid coil 202a, so that when the pressure switch
220 again closes after its momentary opening, it will not again
energize the solenoid coil 202a. Energization of relay coil 272
closes the relay contact 276, which electrically connects the relay
coil 272 between the bus lines 270 and 238, thereby holding the
relay 274 in its energized condition with contact 278 open and
contact 276 closed. Closure of contact 276 also electrically
connects the piston operating valve 222 between the bus lines 270
and 238, thereby actuating the valve 222 to provide hydraulic fluid
under pressure to the hand gun cylinder 24 to effect the second or
pull-up phase of operation of the tool.
This condition of the circuit remains in effect until pull-up is
completed as sensed by the adjustable pressure switch 232 which,
due to increase of back pressure in the hydraulic line 226, moves
from its normally open position to a momentarily closed position
wherein it electrically connects the coil 280 of a relay 282
between the bus lines 270 and 238. Relay 282 has three contacts, a
normally closed contact 284, and normally open contacts 286 and
288. The momentary closure of adjustable pressure switch 232 to
energize the relay coil 280 causes a relay holding circuit to be
completed between bus lines 270 and 238 by closure of the normally
open relay contact 288, so that when pressure switch 232 again
opens upon a drop of pressure in hydraulic line 226, the relay 282
will remain actuated. Actuation of relay 282 opens relay contact
284 which is in the circuit providing current to relay coil 272 and
piston operating solenoid valve 222, thereby releasing the relay
274 and the piston operating solenoid valve 222, cutting off the
supply of hydraulic fluid pressure to the hand gun cylinder 24.
Actuation of relay 282 further closes its normally open contact 286
which serves to electrically connect the directional control valve
solenoid 202b between bus lines 270 and 238 so as to shift the
directional control valve 202 to the left from the center position
as illustrated in FIG. 22, thereby actuating the hand gun hydraulic
motor 72 in the anticlockwise direction for the final or unscrew
mode of operation of the apparatus.
Accordingly, when relay 282 is actuated at the commencement of the
third or unscrew mode of operation, it causes release of the
remainder of the circuit except for the solenoid-operated air valve
184 which remains energized to keep the hydraulic pump 194
operative, and except for the solenoid 202b of the directional
valve 202 and the holding circuit itself for the relay 282. Then,
when the hand gun mandrel 52 has unscrewed free of the installed
blind fastener sleeve, release of the trigger switch button 132
allowing the hand gun switch 136 to open disconnects the power
source from conductor 268 and hence from the bus line 270, thereby
releasing relay 282 and hence also releasing the solenoid coil 202b
of directional control valve 202 so that valve 202 returns to the
center position as illustrated in FIG. 22. This returns the circuit
to its full reset position, ready for another cycle of operation
upon closing of the hand gun switch 136. However, with the selector
switch 244 left in the "auto" position, the indicator light 264
will remain illuminated to indicate that the apparatus is prepared
for another cycle of operation.
The "unscrew" position of selector switch 244 permits the unscrew
mode of operation of the apparatus to be employed pursuant to
actuation of the hand gun switch 136 without cycling through the
screw-in and pull-up modes. Such independent use of the unscrew
mode of operation may be desirable in the event the mandrel 52
should inadvertently become stuck in a blind fastener sleeve and it
should be desired to simply back the tool out of the sleeve. Moving
the selector switch 244 to the "unscrew" position closes contacts
256 and 260 thereof. Contact 256 connects line conductor 240 to the
conductor 262, which turns on the indicator light 264 and energizes
the circuit to hand gun switch 136. Closure of contact 260 connects
the conductor 268 from the hand gun to a conductor 290 which is
connected to one side of the directional control valve solenoid
coil 202b, the other side of which is connected to bus line 238.
Accordingly, closure of the hand gun switch 136 simply completes a
circuit to the solenoid coil 202b to cause the directional control
valve 202 to shift to the left from the center position as
illustrated in FIG. 22, thereby causing the hand gun hydraulic
motor to turn anticlockwise for the unscrew mode, which mode
continues until the hand gun switch 136 is released.
If the hand gun switch button 132 is released to open the hand gun
switch 136 at any time during either the automatic operation of the
apparatus with the selector switch 244 in the "auto" position or
during the unscrew mode as determined by positioning the selector
switch 244 in the "unscrew" position, the entire electrical system
will be de-energized, with the exception of the indicator light 264
which will remain illuminated, and all functions will cease. If the
selector switch 244 is in the "auto" position, when the hand gun
switch button 132 is again depressed to close the switch 136,
cycling of the apparatus will again commence from the beginning,
the apparatus going through the screw-in, pull-up and unscrew modes
in sequence. If the selector switch is on the "unscrew " position,
reclosing the hand gun switch 136 will simply cause resumption of
the unscrew mode.
If, for example, the automatic operation of the apparatus should be
interrupted by opening of the hand gun switch 136 during the
screw-in mode, rotation of the mandrel 52 will simply stop. Then,
when the switch 136 is again closed, the first or screw-in mode
will assume, and will continue until the stall condition of the
hydraulic motor switches the apparatus to the second or pull-up
mode, and the cycling will continue through the pull-up and unscrew
modes. As another example, if the hand gun switch 136 should be
opened during the pull-up mode, the complete de-energization of the
system will release the pull-up force, but leave the mandrel 52
screwed into the blind fastener sleeve. Then, when the hand gun
switch 136 is reclosed, the system will go through all three
cycles, although the screw-in cycle will be quickly traversed since
the hydraulic motor 72 will almost immediately stall due to the
fact that the mandrel is already fully threadedly engaged with the
blind fastener sleeve. This stall condition of the hydraulic motor
72 switches the apparatus to the pull-up mode which is then
effective for complete pull-up as determined by back pressure in
the hydraulic system acting upon the adjustable pressure switch
232, and then the system will automatically switch to the unscrew
mode.
Similarly, if automatic operation is terminated by opening of the
hand gun switch 136 during but before the completion of the unscrew
mode, when the switch 136 is again closed, the apparatus will cycle
through all three modes. During the screw-in mode, the mandrel will
screw back into the blind fastener sleeve to the extent that it had
already screwed out, at which time the hydraulic motor 72 will
stall to switch to the pull-up mode. The pull-up mode will be
quickly traversed since the blind fastener sleeve will already be
fully upset, and then the apparatus will again automatically switch
to the unscrew mode, which will be completed assuming the hand gun
switch 136 is held long enough in the closed position.
FIGS. 16 through 21 illustrate a presently preferred remote power
unit generally designated 292 for providing the hydraulic driving
power to the hand gun 10 pursuant to electrical control from the
hand gun. The power unit 292 is preferably constructed in the form
of a movable cart having a housing 294 with front, rear, and right
and left side walls 296, 298, 300 and 302, respectively. The
housing 294 stands on a stationary rear rest member 304 and a pair
of forward wheels 306, and a forwardly and upwardly projecting
handle 308 permits convenient moving of the power unit 292 by
simply tipping the housing forwardly on the wheels 306 to raise the
rear rest member 304 above the floor.
FIG. 16 illustrates the air motor 190 coupled to the hydraulic pump
194 through the drive connection 196, and also illustrates a
hydraulic fluid filter 310 in the rear of the housing and a
hydraulic reservoir filler port 312 projecting from the front of
the housing which are not illustrated in the hydraulic system
diagram of FIG. 22. The hydraulic pump 194 is shown located within
the reservoir 210, and the hydraulic pump output is fed through a
pipe 314 to a manifold 316 which contains most of the hydraulic
system lines or conduits diagrammatically illustrated in FIG. 22.
The manifold 316 is laid out generally horizontally in overlying
relationship above the reservoir 210. As best shown in FIGS. 16 and
17, supported on top of the manifold 316 are the check valve 198,
the directional control valve 202, speed control valve 214, piston
operating valve 222, and relief valve 233. Projecting rearwardly
from the manifold 316 are the back pressure valve 235 and hydraulic
filter 310.
As best illustrated in FIGS. 16 and 18, the adjustable pressure
switch 232 is mounted on the front wall 296 of the power unit
housing 294.
The air system is best shown in FIG. 19 looking from the rear
inside the housing 294. Illustrated in FIG. 19 are air filter 178
and pressure regulator 180, which are shown as a combination unit,
lubricator 182, the solenoid-operated air valve 184, air flow
control valve 188, and air motor 190. The air inlet conduit 176 is
provided with shop air through an air input hose 318 shown in FIG.
20.
Also shown in FIG. 20 on the left-hand wall 302 are the selector
switch 244 and indicator light 264 forming part of the electrical
circuit diagram in FIG. 23.
The connections of the flexible hoses and electrical cable from the
hand gun at the front wall 296 of the power unit are best
illustrated in FIGS. 17, 18, and 21. Suitable connectors for the
hoses and electrical cable are mounted on a connector panel 320 on
front wall 296. These connectors include an electrical connector
322 for the electrical cable 144 from the hand gun, and hose
connectors 324, 326, 328, and 330, for the respective hoses 216,
218, 228, and 230, all of which are diagrammatically illustrated in
FIG. 22. Also mounted on the connector panel 320 is a plugged
connection 332 to which a system pressure gauge may be connected
for testing purposes. The electrical cable and hose connections to
the hand gun are diagrammatically illustrated in FIG. 21, which
illustrates the connector panel 320 and the base of the handle of
the hand gun 10 substantially as illustrated in FIG. 3, with dotted
line electrical cable and hose connections therebetween.
While one automatic sequencing circuit arrangement has been
illustrated in FIGS. 22 and 23 and described herein, it is to be
understood that other circuit means may be employed to provide
automatic sequencing of the hand gun between the screw-in, pull-up,
and screw-out modes of operation thereof within the scope of the
invention. Thus, for example, the circuit means may include as a
part thereof a conventional "sequence valve" which has built into
it pressure responsive sequencing means which would serve as the
equivalent of the pressure responsive sequencing means illustrated
in FIGS. 22 and 23 and described in connection therewith.
While the instant invention has been shown and described herein in
what is conceived to be the most practical and preferred
embodiment, it is recognized that departures may be made therefrom
within the scope of the invention, which is therefore not to be
limited to the details disclosed herein.
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