U.S. patent number 3,685,070 [Application Number 05/050,223] was granted by the patent office on 1972-08-22 for forging machine transfer.
This patent grant is currently assigned to The National Machinery Company. Invention is credited to Harry A. Dom, Herbert L. McClellan, Robert E. Wisebaker.
United States Patent |
3,685,070 |
McClellan , et al. |
August 22, 1972 |
FORGING MACHINE TRANSFER
Abstract
A transfer system is disclosed for progressively transferring
work pieces between die stations of a progressive forging machine.
The transfer includes a pivoted frame on which a reciprocating
slide is supported. Work pieces gripping fingers are carried by the
slide for movement from a gripping position to a release position.
Pivotal movement of the frame moves the fingers out away from the
die face to provide clearance for turning of the fingers. Finger
turning is in response to reciprocation of the finger supporting
slide. A first cam driven linkage controls the oscillating pivotal
movement of the frame and a second cam driven linkage controls the
gripping and release of the fingers. The two linkages are arranged
to be substantially unaffected by the pivotal movement of the frame
and the reciprocating movement of the slide. The transfer is
arranged to permit easy removal of one slide with work piece
gripping fingers thereon and the substitution of a different slide
with a different type of work piece gripping fingers. Therefore,
the transfer system can be easily modified to accommodate different
types of work pieces and to permit different types of forming
operations within a single machine.
Inventors: |
McClellan; Herbert L. (Tiffin,
OH), Dom; Harry A. (Tiffin, OH), Wisebaker; Robert E.
(Tiffin, OH) |
Assignee: |
The National Machinery Company
(Tiffin, OH)
|
Family
ID: |
21964040 |
Appl.
No.: |
05/050,223 |
Filed: |
June 26, 1970 |
Current U.S.
Class: |
470/139;
72/405.09; 72/421 |
Current CPC
Class: |
B30B
15/30 (20130101); B21K 1/64 (20130101); B21K
1/44 (20130101) |
Current International
Class: |
B30B
15/30 (20060101); B21K 1/44 (20060101); B21K
1/00 (20060101); B21K 1/64 (20060101); B21d
043/02 () |
Field of
Search: |
;10/12T,12.5,11T,12R,11R,76T ;72/405,421,358 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lanham; Charles W.
Assistant Examiner: Crosby; Gene P.
Claims
WHAT IS CLAIMED IS:
1. A machine for forging work pieces comprising a main frame
assembly for supporting a plurality of dies at laterally spaced die
stations, a transfer assembly operable to progressively transfer
work pieces laterally between said die stations, said transfer
assembly including a rotatable cam shaft journaled on said main
frame assembly and extending laterally with respect thereto, a
first transfer housing pivoted on said main frame assembly for
oscillating rotation about a first axis parallel with said cam
shaft, a first slide reciprocably mounted on said first transfer
housing for movement laterally of said main frame assembly and
oscillating movement about said first axis with said first transfer
housing, first work piece gripping means on said slide providing
fingers operable to grip a work piece at one die station and
operable to turn such work piece end-for-end while transferring it
to a subsequent die station, a first linkage powered by said cam
shaft operable to oscillate said first transfer housing about said
first axis in timed relationship to the operation of said machine,
a second linkage powered by said cam shaft operable to control
gripping and release of said fingers independent of turning thereof
and in timed relationship to the operation of said machine, and
drive means operable to reciprocate said slide in timed
relationship to the operation of said machine.
2. A machine for forging work pieces as set forth in claim 1
wherein turning means are provided to turn said fingers in response
to relative movement between said slide and transfer housing.
3. A forging machine as set forth in claim 2 wherein said turning
means are releasable to permit said fingers to transfer a work
piece without turning, and lock means are provided to prevent
turning of said fingers.
4. A forging machine as set forth in claim 1 wherein said first
linkage includes a connection which is releasable to render said
first linkage inoperable, and a second slide is provided for
mounting on said transfer housing to replace said first slide, said
second slide being provided with second work piece gripping fingers
for transferring work pieces between said die stations without
turning, said second linkage being operable to control the gripping
and releasing of said second fingers.
5. A machine for forging work pieces as set forth in claim 1
wherein said second linkage includes a cam on said cam shaft, a
link pivoted on said first transfer housing, and follower means on
said link engageable with said cam and movable along a path
substantially through said first axis in response to rotation of
said cam.
6. A machine for forging work pieces as set forth in claim 5
wherein said path is substantially bisected by said first axis, and
spring means are connected between said link and first transfer
housing resiliently urging said follower means toward said cam.
7. A machine for forging work pieces as set forth in claim 1
wherein said cam shaft rotates about a second axis spaced from and
parallel to said first axis.
8. A transfer assembly for forging machines or the like comprising
a support, a tubular spindle journaled on said support for rotation
about its central axis, a pair of opposed gripper fingers pivoted
on said spindle for opening and closing movement in a direction
normal to said central axis, said fingers being symmetrical with
respect to said axis and being adapted to grip a work piece located
on said axis, each finger providing an operating projection
extending to said central axis, an operating assembly extending
along said spindle and axially movable relative thereto, axial
movement of said operating assembly moving said operating
projections and causing opening and closing movement of said
fingers, a fluid pressure spring mounted along said axis
resiliently biasing said operating assembly in one direction, an
external operating surface on said operating assembly extending
substantially normal to said axis, a link pivoted on said support
having a portion engaging said operating surface operable to move
said operating assembly against the action of said fluid spring and
control the opening and closing of said fingers.
9. A transfer assembly as set forth in claim 8 wherein said
operating surface is intermediate the ends of said spindle, and
said spindle is provided with lateral openings, said operating
assembly including connecting means extending through said openings
connecting said external operating surface and the internal portion
of said operating assembly.
10. A transfer assembly as set forth in claim 8 wherein said fluid
spring includes a cylinder mounted on the end of said spindle
opposite said fingers, and an axially movable piston connected to
said operating assembly.
11. A transfer assembly as set forth in claim 10 wherein said
transfer includes a frame, said support is a slide reciprocable
relative to said frame, turning means interconnecting said spindle
and frame operate to turn said spindle in response to reciprocation
of said spindle with said slide.
12. A transfer assembly as set forth in claim 11 wherein said
turning means is releasable to render it inoperative, and stop
means are provided to prevent rotation of said spindle relative to
said slide.
13. A transfer assembly as set forth in claim 8 wherein a plurality
of similar gripper assemblies are mounted on said support, said
support is provided with fluid pressure conduit means connected to
supply fluid under pressure to said fluid spring of each gripper
assembly.
14. A transfer assembly as set forth in claim 13 wherein said
transfer includes a frame, said support is a slide reciprocable
relative to said frame, and said conduit means include a flexible
portion connecting said slide to a source of fluid under pressure
to accommodate the reciprocation of said slide.
15. A transfer assembly as set forth in claim 14 wherein said
flexible portion is provided with a coupling, disconnecting said
coupling operating to release the pressure in each of said springs,
each fluid spring being connected to its associated spindle and
turning therewith with respect to said slide, and a flexible line
connects each fluid spring and said conduit means to accommodate
such turning movement.
16. A transfer assembly as set forth in claim 8 wherein said
operating assembly includes bearing means engageable with one of
said operating projections, the other of said operating projections
engaging said one operating projection on the side thereof opposite
said bearing means, and a spring urging said other operating
projection toward said bearing means.
17. A machine for forging work pieces comprising a main frame
assembly for supporting a die at a die station, a slide on said
frame for moving a tool toward and away from said die station, a
transfer operable to transfer work pieces from a first position to
said die station including work piece gripping means movable from a
first position in which it grips a work piece to a second position
in which it delivers said work piece to said die station, a
mechanical drive for said transfer, said mechanical drive including
an overload clutch providing a drive clutch member and a clutch
driven member, said clutch members being connected to transmit
torque therebetween when in a drive position and being movable
relative to each other to a release position when the torque
applied therebetween exceeds a predetermined value, drive means
including mating gears connected to drive said drive clutch member,
and support means mounting said mating gears permitting their
movement in unison with said drive member when it moves to said
release position.
18. A machine as set forth in claim 17 wherein said drive means
includes a fluid spring including piston and cylinder elements
operable to resiliently urge said gears in one direction, one of
said elements being pivotally supported on said frame at a location
spaced from said gears, said support means being on said one
element, movement of said clutch members to said release position
causing pivotal movement of said one element.
19. A machine as set forth in claim 18 wherein said one element is
the cylinder element of said fluid spring, said cylinder element
providing an integral reservoir having a volume substantially
greater than the volume displaced during operation of said spring,
and a supply line connecting said reservoir to a source of fluid
under pressure.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to machines for progressively cold
forming work pieces and more particularly to a novel and improved
automatic transfer for such machines.
PRIOR ART
Various types of forging machines are provided to progressively
form parts at a plurality of die stations. In many instances rod or
wire stock is fed into the machine and is cut into blanks or slugs
which are then progressively transferred to a plurality of die
stations in which they are progressively formed to the desired
shape. In the past it has been customary to construct a given
machine for use in the manufacture of a particular type of product
and to provide a transfer which is suitable only for transferring
such product.
For example, when a machine is intended for forming relatively long
header parts, such as bolts or the like, the practice has been to
equip the machine with a transfer which is incapable of turning the
blank between the die stations and which is provided with gripper
fingers that open wide enough to clear the relatively large tools
often required for such heading operations. An example of such a
machine is illustrated in the U.S. Pat. No. 2,278,103.
In other instances, the machine is used to form relatively short
parts which must be turned end-for-end between at least some of the
die stations. Such a machine is often equipped with a transfer
operable to transfer parts between die stations selectively with or
without turning. An example of such a transfer is illustrated in
the U.S. Pat. No. 3,165,766.
Another transfer for this general category of parts is a transfer
of the type used in the manufacture of nuts. Such transfers are
often arranged so that the fingers are spring biased toward the
closed or gripping position and are not mechanically opened for
release of the part. Instead, the part or fingers are arranged to
cause the fingers to cam apart slightly as the part is pressed into
the fingers when it is ejected from the die. The subsequent tool
then pushes the part out of the fingers into the subsequent die. In
the past, the type of parts which could be manufactured in a
particular machine was limited to the type of part which could be
conveniently transferred by the transfer installed on the machine.
Therefore, if such a machine was provided with a transfer which was
capable of transferring headed parts and incapable of turning a
blank end-for-end, parts requiring such turning movement could not
be manufactured on such machine. On the other hand, if the machine
was equipped with a transfer capable of turning the parts and
incapable of handling headed parts or relatively long parts, the
machine could not be used for manufacturing of elongated or headed
parts.
SUMMARY OF THE INVENTION
The present invention is directed to a novel and improved transfer
for automatically and sequentially transferring parts between a
plurality of die stations. The transfer assembly is arranged so
that it can be easily modified to permit a change over from a
mechanism particularly suited for the transfer of relatively long
or headed parts without turning the parts end-for-end to a transfer
particularly suited for turning blanks end-for-end. Consequently, a
machine incorporating a transfer in accordance with the present
invention is more versatile in that the transfer can be modified
easily and conveniently so that the machine can be used to
manufacture several different categories of parts.
There are a number of different aspects to the present invention.
In accordance with one aspect of this invention a transfer is
provided in which the part or blank gripping fingers are supported
on a reciprocating slide for simple reciprocating movement. Such
slide is easily removed from the transfer to permit substitution of
another slide having a different type of blank gripping fingers
thereon. Since the slide with the gripping fingers supported
thereon is easily removed from the machine, the setup of the
fingers and adjustment for a particular part can be easily
accomplished in a separate fixture or jig. Therefore, the down time
of the machine required for change over is minimized.
In accordance with another aspect of this invention the transfer is
provided with a forward slide supporting frame pivoted for
oscillating movement with respect to the die breast of the frame in
combination with cam driven power means arranged to cause such
oscillating movement. The slide is carried on the oscillating frame
for simple reciprocating movement with respect thereto. The
oscillation of the frame causes blank gripping fingers carried by
the slide to swing away from the die breast to provide clearance
when blank turning is required. This same movement causes a lifting
of the fingers and can be used to raise the fingers up enough to
clear the punch to permit finger return movement to commence before
the punch is withdrawn clear of the fingers. Also, such swinging
movement is used in some instances to move blanks out of the dies
at one station and into the dies at a subsequent station. The drive
for causing oscillation of the forward frame section can be
disconnected easily when the transfer mechanism does not require
such oscillating movement. For example, such oscillating pivotal
movement is not normally required when the transfer does not
involve turning of the blank as it is transferred between adjacent
stations.
In accordance with another aspect of this invention a novel and
improved turn around gripper structure is provided. In the
illustrated embodiment the gripper assembly is pivoted for
oscillating movement about a vertical center axis. A pneumatic
spring mounted along the pivot axis provides the finger gripping
force. The various elements of the gripper assembly are arranged to
facilitate easy adjustment.
In accordance with still another aspect of this invention, a novel
and improved transfer drive is provided which incorporates an
overload clutch mechanism which is substantially immuned to
malfunction.
These and other aspects of the invention are described in the
following detailed description of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the preferred transfer incorporating the
present invention with parts removed for purposes of
illustration;
FIG. 2 is an end view of the transfer illustrated in Figure 1;
FIG. 3 is a cross section taken generally along 3--3 of Figure 1
with parts removed for purposes of illustration;
FIG. 4 is a fragmentary schematic perspective illustrating the
drive mechanism for pivotally oscillating the forward transfer
frame;
FIG. 5 is a fragmentary schematic perspective illustrating the
linkage for controlling the opening and closing movement of the
transfer fingers;
FIG. 6 is a fragmentary front elevation of a novel and improved
gripper transfer assembly which is operable to transfer a work
piece or the like selectively with or without turning during
transfer;
FIG. 7 is a longitudinal section taken along 7--7 of FIG. 6
illustrating the structural detail of the transfer illustrated in
FIG. 6;
FIG. 8 is a fragmentary schematic perspective view similar to FIG.
5 illustrating the gripper operating linkage in combination with
non-turning transfer grippers;
FIG. 9a is a side elevation partially in section of the drive for
reciprocating the transfer slide, and;
FIG. 9b is a fragmentary plan view of the drive illustrated in
Figure 9a.
DETAILED DESCRIPTION OF THE DRAWINGS
The illustrated embodiment of this invention is a transfer for
progressively transferring work pieces from one die station to the
next in a progressive cold forging machine of the general type
illustrated in application Ser. No. 784,806, filed Dec. 18, 1968,
now U.S. Pat. No. 3,604,242. Such machines include a main frame in
which a slide is reciprocable toward and away from a die breast
supported in the frame. Usually, dies are mounted in the die breast
at laterally spaced locations or die stations. Cooperating tools
are provided on the slide at each die station and are arranged so
that a work piece or blank is progressively formed in each die
station until the desired product is obtained after the working of
the last die station of the machine. In some instances machines of
this nature are provided with means to supply separate work pieces
to the machine for transfer to the first die station. A more common
arrangement, however, provides for a feed of wire or rod stock into
the machine to a shearing station wherein the stock is cut into
blanks or work pieces. Such blanks or work pieces are then
transferred to the first die station and subsequently to the
remaining die stations. Such machines may be used to manufacture
various types of parts. In some instances the blank is upset or
headed as for example to form a bolt blank. In other instances, the
blank is shaped so that it may be threaded and made into a nut. In
still other instances, the machine is used to form other types of
articles.
The present invention is directed to a novel and improved automatic
transfer for a progressive cold forging machine or the like which
may be used in the manufacture of a variety of different parts. The
transfer can be used for relatively short parts and can be arranged
to transfer the part between adjacent die stations either with or
without turning as required for the manufacturing process.
Similarly, the transfer may be used for longer parts including
parts which involve heading such as bolt blanks or the like.
Referring to FIGS. 1 through 3, the illustrated transfer is mounted
on the main forging machine frame 10 in a position above and
substantially adjacent to the laterally extending die breast 11
illustrated in FIG. 3. Dies 11a are mounted in the breast and
cooperating tools 11b carried by the main slide cooperate with the
dies to progressively form the work pieces. The transfer includes a
support frame 12 which is pivotally supported at its rearward end
by spaced pivot pins 13 (illustrated in FIGS. 1 and 2). The support
frame 12 is provided with integrally formed generally curved
support sections 14 which extend from opposite ends thereof to the
pivot pins 13. The pivot pins 13 are mounted in a support assembly
which is secured to the machine frame 10. The support assembly 16
is provided with means to provide both horizontal and vertical
adjustment for accurate positioning of the support frame 12.
The support frame 12 is normally maintained in the position
illustrated by a tow clamp assembly 17 located adjacent to each end
of the support frame 12 adjacent to its forward edge. The tow clamp
assembly 17 may be released when servicing is required to allow the
entire transfer frame assembly to be pivoted up around the axis of
the pivot pins 13.
A pivot frame 18 is supported at its ends by pivot pins 19 carried
by the support frame 12 for oscillating movement about a pivot axis
21. Cam driven linkage means, discussed in detail below, are
provided to cause oscillating rotation of the pivoted frame 18
about the axis 21 in timed relationship to the operation of the
machine.
Mounted for longitudinal reciprocation on the forward end of the
pivot frame 18 is a transfer slide 22. In FIGS. 2 and 3 this slide
22 is illustrated without transfer gripper fingers mounted thereon.
However in use, five similar gripper finger assemblies 23 of the
type illustrated in FIGS. 6 and 7 are normally pivoted in bosses 24
on the slide 22 at spaced locations along the slide. The spacing
between the gripper transfer assemblies 23 is equal to the spacing
between the adjacent die stations in the forging machine. A powered
drive as illustrated in FIGS. 9a and 9b is provided to power the
slide in its reciprocating movement with respect to the pivoted
frame 18. This drive is discussed in detail below.
Supported on the main frame 10 of the machine is a cam shaft 26
which is journaled for rotation about its axis 27 in shaft supports
28 located at axially spaced locations along the cam shaft 26.
Preferably, four shaft supports 28 are provided with two
substantially adjacent to the center portion of the cam shaft and
two provided at its ends. The cam shaft 26 is powered in timed
relation to the operation of the machine. Normally, it is connected
directly to the main machine drive and is arranged to rotate
through one complete revolution as the main machine slide moves
back and forth through one complete cycle. The cam shaft is
provided with a plurality of spaced cams which drive the linkage
used to oscillate the support frame 18 and also drive the linkages
which operate to control the gripping and release of the transfer
fingers carried by the slide 22. Here again, the structural detail
and mode of operation of these linkages is discussed in detail
below.
The structure of the gripper finger assemblies 23 is illustrated in
FIGS. 6 and 7. It should be understood that each of the assemblies
23 is similar, however, their operation can be arranged to provide
either turning or non-turning type transfer. Each of the assemblies
23 includes a tubular spindle 31 journaled in bearings 32 in the
bosses 24 for rotation about its central axis 33. The axis 33 is
vertical and parallel to the die face 34 (illustrated in FIG. 3)
when the transfer is in the gripping and releasing positions. The
axis 33, however, is pivoted out away from the die face 34 when the
pivoted frame 18 is pivoted from the position illustrated in FIG.
3.
Referring to FIGS. 6 and 7, the vertical positioning of the spindle
31 is provided by a spacer 36 positioned against a check spacer
assembly 37 on the upper boss 24. The spacer 36 is held against a
shoulder 40 by an assembly including a thrust bearing 38, a gear
sector 39, and a cylinder 41 of an air spring. Therefore, the
spindle 31 is vertically positioned with respect to the slide 22
even though it is free to rotate about a central axis 33.
Mounted on the lower end of the spindle 31 are two gripper finger
assemblies 42 and 43 which are pivotally supported on the spindle
for limited rotation about the pivot axes 44 and 46, respectively.
The two axes 44 and 46 are parallel to each other and are equally
spaced from, and are on opposite sides of the central axis 33. The
finger assembly 42 includes a finger element 47 which is secured in
position by a bolt 48. Similarly, the finger assembly 43 is
provided with a finger element 49 mounted by a bolt 51. However, in
this instance, an adjustment screw 52 is provided for adjustment of
the finger member 49 with respect to its support arm 53.
The gear sector 39 is clamped to the spindle 31 by a bolt 56 when
it is desired to rotate the spindle during transfer movement. Each
gear sector 39 meshes with a gear rack 57 mounted on the pivoted
frame 18 and the sector is proportioned so that as the slide 22
moves with respect to the rack 57 on the pivot frame 18 between the
gripping position and the release position, the sector 39 and, in
turn, the spindle 31 rotates through 180.degree. . When it is
desired to arrange the transfer of a particular gripping assembly
23 so that turning does not occur during the transfer movement, the
bolt 56 is loosened and the slide is moved until the sectors are
clear of the rack. The bolt is then tightened with the sector out
of engagement with the rack and an L-shaped lock member 58 is
dropped down from its release position illustrated in FIG. 7 until
its inner surface 59 engages a flat 61 formed on the spindle. A
pair of nuts 62 retain the lock member 58 in either its release
position illustrated or its locked position. When the lock member
58 is in the release position a guide pin 63 is located in a bore
64 to insure that the lock member cannot drop down against the flat
61. When it is desired to move the lock member to the locked
position, the nuts 62 are merely loosened and the lock member is
slipped outward off of the pin and dropped down into the locked
position. The tightening of the nuts then causes engagement with
the flat 61 which prevents rotation of the spindle with respect to
the bosses 24. The lock member 58 is provided with a slot-type
opening 66 to receive the pin 63 when the member is in the locking
position.
Extending down through the spindle 31 is an operating assembly
which controls the gripping and release of the fingers 42 and 43.
This assembly includes an operating member 67 which is axially
movable within the spindle 31 and is resiliently urged in an upward
direction with respect to the spindle by a pull rod 68 connected to
the piston 69 within the air spring cylinder 41. Air under pressure
is admitted to the spring chamber 71 through the fitting 72 and a
flexible hose 73 so that the chamber 71 below the piston is
pressurized and produces a force urging the piston in an upward
direction. This, in turn, through the pull rod 68 which is
connected at its lower end to the operating member 67, resiliently
urges the operating member in an upward direction. Each flexible
hose 73 is connected to a passage 75 in the slide. This passage is,
in turn, connected to a supply of pressure by a flexible hose
81.
A cross pin 74 at the lower end of the operating member 67 is
provided with a bearing 76 which engages the lower side of a
lateral arm 77 on the finger assembly 43. Therefore, the force of
the air spring tends to cause clockwise movement of the projection
77 as viewed in FIG. 6 and inward or clamping movement of the
finger member 49. Positioned above the projection 77 is a second
lateral projection provided on the finger assembly 42. In this
instance the upward force of the air spring tends to produce
anticlockwise rotation of the finger assembly 42 and consequently,
inward movement of the finger member 47 toward the finger member
49. A spring plunger 79 within the operator member 67 is urged in a
downward direction by a spring 80 and maintains contact between the
two projections 77 and 78 and contact between the projections 77
and the bearings 76. This spring, because it takes up all
clearance, insures that the arms both open and close in exact
unison even after the machine has operated a sufficient time to
develop some wear in the parts. Therefore a blank is uniformly
gripped or released in the same manner and in the same location
each time the machine cycles and there is no tendency for one
finger to operate ahead or behind the other finger. The spring does
not support gripping loads but only supplies enough force to cause
finger opening. Therefore, a relatively light spring is
sufficient.
A cam driven linkage, best illustrated in FIG. 5, is provided to
overcome the action of the air spring and functions to control the
closing of the gripper fingers for gripping and the opening of the
fingers for release in timed relationship to the operation of the
machine. Mounted on the cam shaft 26 and associated with each of
the gripping assemblies is a gripper control cam 82. In FIG. 1
there are six such cams illustrated even though the slide provides
only five gripper assemblies. The left five cams 82 are
respectively associated with the five gripper assemblies and
independently control the operation of each associated assembly.
The right hand cam 82 does not function when the slide 22 is
mounted on the transfer. It functions, however, when a substitute
slide having a different type of transfer gripper is mounted on the
transfer as will be discussed below.
Associated with each gripping assembly is a tappet link 83
journaled on a shaft 84 carried by the pivot frame 18. The tappet
link is provided with an upstanding projection 86 and a follower
arm 87 pivoted at 88 on the projection 86. An adjusting screw 89 is
threaded through the upper end of the projection 86 and extends
into abutting relationship with a boss 91 on the follower arm 87.
With this structure, the position of the follower arm with respect
to the tappet arm can be easily adjusted.
Journaled on the follower arm 87 is a follower roller 92. A spring
93 extending between the pivot frame 18 and the tappet arm 83
biases the tappet arm in a clockwise direction to maintain the
follower roller 92 in engagement with a cam. In the drawings, the
cams 82 are illustrated as simple cylinders for purposes of
illustration. However, it should be understood that they are
provided with appropriately positioned lobes which cause
oscillating rotation of the tappet arm with respect to the pivot
frame 18. The action of the cam 82 causes the follower 92 to move
along an arc path around the axis of the shaft 84 as illustrated in
FIG. 3 by the dotted line 94. The various elements are proportioned
so that this path extends substantially through and is bisected by
the axis 21 of pivotal movement of the pivot frame 18. Therefore,
the pivoting movement of the frame 18 does not produce any
substantial movement of the follower along the periphery of the cam
82 and consequently, the function of the cam and the follower is
substantially uneffected by the pivotal movement of the pivot frame
18.
Each tappet lever 83 is provided with a forwardly extending
projection 95 with a laterally extending bar 96 mounted on its end.
The lower surface of the bar provides a track surface along which a
roller follower 97 moves. The roller follower 97 is mounted on a
link 98 supported for oscillating rotation by a lateral shaft 99
mounted in the slide 22. Secured to the opposite end of the shaft
99 is a second link 101 having a forked end 102 engageable along
diametrically opposite sides with the upper surface of a bearing
race 103.
The upper race 103 is part of an antifriction bearing 104 best
illustrated in FIG. 7. This bearing is guided and supported by a
bushing 106 which is, in turn, connected to the operating member 67
by a cross pin 107. The cross pin 107 extends through a closed
slotted opening 108 in the spindle 31 so that the pin is free for
limited vertical movement with respect to the spindle. With this
structure downward movement of the forked ends 102 as viewed in
FIG. 7 causes similar downward movement of the operating member 67
against the action of the air spring. The upward movement of the
forked ends 102 is limited by an adjusting screw 109 which
functions to adjustably limit the upward movement of the operating
member 67 and, in turn, the degree of closing of the finger members
47 and 49.
The gripping and releasing operation is controlled by the rotating
cam 82 associated with each finger assembly. As a lobe or high
point on the cam moves under the cam follower 92 it causes
anticlockwise rotation of the tappet lever 83. This, in turn,
causes the followers 97 to be pressed down and results in finger
opening movement for releasing a work piece or blank. Of course, as
the lobe of the cam moves past the follower 92, the action of the
compressed air within the chamber 71 causes finger closing movement
as the tappet lever 83 is allowed by the cam 82 to rotate in a
clockwise direction. The lower surface of the lateral bar 96 is
aligned with the direction of movement of the slide 22.
Consequently, the longitudinal movement of the slide does not
affect the finger opening and closing operation determined by the
cam 82.
As viewed in FIG. 3, it is preferable to arrange alternate tappet
levers so that their projections 95 are longer or shorter than the
adjacent projections. With this arrangement, one lever does not
interfere its adjacent lever even though the lateral bar 96 has a
length exceeding the spacing between adjacent gripper assemblies
and the length of travel of the slide 22. With this arrangement, of
course, the follower lever 98 of each gripping assembly has to be
offset from the adjacent follower lever in a similar manner to
provide proper alignment with the associated lateral bar 96.
Reference should now be made to FIGS. 1, 3, and 4 which illustrate
the linkage for controlling the pivoting movement of the pivoted
frame 18 of the transfer. A centrally located cam 111 is mounted on
the cam shaft 26 to control the pivoting movement of the frame. The
cam 111 is engaged by a roller follower 112 carried by a follower
lever 113. The follower lever 113 is pivotally connected at 114 to
a shaft 116 journaled on the support assembly 16 in bearings 117
illustrated in FIG. 1. A pair of bolt fasteners 118 cooperate with
the pivot 114 to lock the follower arm 113 with respect to the
shaft 116. Therefore, when the cam 111 causes a lobe to pass under
the follower 112, the shaft 116 is caused to rotate in a clockwise
direction. Here again, the cam 111 is illustrated as a simple
cylinder but it should be understood that the cam would be provided
with lobes shaped to produce the required rotation of the shaft 116
in proper timing with the operation of the machine.
Mounted on the opposite ends of the shaft 116 are similar depending
arms 119 which are connected at their lower ends with push rods
121. Mounted on the forward end of each push rod is a cam element
122 which engages with a roller follower 123. The roller follower
123 is journaled on the pivot frame 18 at a location spaced from
the pivot axis 21 of the frame 18.
When the cam 111 causes clockwise rotation of the shaft 116 the two
push rods 121 move forward and through their contact with the
follower roller 123 causing clockwise rotation of the pivot frame
18 about its pivot axis 21. Since the pivoting force is applied at
opposite ends of the pivot frame 18 there is substantially no
tendency for the frame to be twisted by this action.
In order to produce a force in an anticlockwise direction on the
pivot frame 18, a pair of similar pneumatic springs 124 are
provided. Each of these springs includes a cylinder 126 supported
at one end on the main frame 14 and a piston connected at 127 to an
upstanding arm 128 integrally formed on the pivot frame 18 at each
end thereof. These springs resiliently urge the pivot frame toward
the operative position illustrated in FIG. 3, but allow the pivot
frame to be rotated in a clockwise direction from this position by
the cam 111. However, since the springs 124 are connected between
the main frame 12 and the pivot frame 18, they do not hinder the
raising of the two frames to the service position after the hold
down clamps 17 are released.
The longitudinal reciprocation of the slide 22 is provided by a
drive mechanism as illustrated in FIGS. 9a and 9b. This mechanism
includes a cam 131 powered by the main machine drive which engages
a follower 132 on a follower arm 133. The follower arm is pivoted
at its lower end so that the passage of a lobe on the cam 131 under
the follower 132 causes movement of the upper end of the follower
arm 133 to the right as viewed in FIG. 9a.
Connected to the upper end of the follower arm 133 is a push rod
134 which is, in turn, connected to a gear rack extension 136 on
the piston 137 of an air spring 138. The rack extension 136 is
guided within a gear box 139 mounted on the forward end of the
spring 138. The rearward end of the spring is pivotally supported
on the machine frame at 141.
Journaled on the gear box 139 is a drive element 142 of an overload
clutch. The drive element is connected to a gear 143 which meshes
with the rack extension 136 and is caused to rotate when the rack
extension reciprocates. The driven member 144 of the overload
clutch 142 is connected to a shaft 146 having a crank member 147
mounted at its upper end.
The clutch assembly is maintained in its engaged position by a
spring assembly including a spring 148 which resiliently biases a
pivoted crank 149 in a clockwise direction and thereby causes a pin
151 to engage the underside of the gear box 139 to press the drive
element 142 into operative engagement with the driven element 144.
However, when the torque which must be transmitted between the two
elements 142 and 144 exceeds a predetermined value determined by
the force of the spring 148, the drive element 142 is cammed down
against the action of the spring 148 causing the entire spring
assembly 138 to pivot around the axis 141 to a clutch disengaged
condition. It should be noted however, that during such downward
movement created by an overload condition on the clutch, there is
no lateral relative movement between the gear 143 and the rack
extension 136 so the force of engagement therebetween by the load
does not resist the declutching operation and does not affect the
torque value at which the clutch will release. With this structure,
the torque that can be transmitted by the clutch is determined only
by the setting of the spring 148 and the clutch functions to
release in a reliable manner when the desired maximum torque is
applied to the clutch. The clutch is normally set so that a
positive drive is maintained and its principal purpose is to
prevent damage to the transfer mechanism in the event that a jam
occurs.
The air spring 138 is provided with an integral reservoir 151 by a
cylinder member 152 which extends around the cylinder sleeve 153
within which the piston 137 reciprocates. The cross sectional area
of the cylinder 153 is substantially smaller than the cross
sectional area of the reservoir 152, so the volume of the reservoir
is substantially greater than the volume displaced by the piston
137. Consequently, the spring provides substantial stroke of the
piston without excessive variations in the pressure of the air
within the device. The reservoir is connected through a pressure
supply line 154 to a controlled source of pressure. However, since
substantial volume is provided within the reservoir 151, very
little flow is required through the supply line and excessive
heating in the supply line does not occur.
The slide 22 is connected to the crank arm 147 by a drive link 156
which extends between the crank and a ball joint fitting 157 on the
end of the slide 22. In operation, the cam 131 causes reciprocating
movement of the follower arm 133 which is converted by the rack and
gear drive to oscillating rotation of the crank 147. This, in turn,
produces the required reciprocating movement of the slide 22. In
the event of a jam that places excessive load on the drive, the
drive element 142 of the clutch moves downward against the action
of the spring 148 to prevent excessive forces from being applied to
the transfer itself.
In some instances it is desirable to remove the slide 22 from the
transfer and to substitute a different slide having either a
different type of gripper fingers or gripper fingers which are
adjusted to transfer a different type of work piece. In such
instance, it is merely necessary to disconnect the drive link 156
from the crank arm 147 and disconnect the hose 81. When this is
done, the slide 22 is pulled out of its transfer along its guide
without disconnecting any of the hoses 73 which individually
connect the finger air springs to the longitudinal air passage 75
extending lengthwise along the slide 22. Therefore, it is not
necessary to disconnect each finger biasing air spring individually
to permit removal of the slide 22. In other instances, when the
finger assemblies are being adjusted, it is desirable to permit
release of the pneumatic spring force so that the fingers can be
manually opened or closed. Since all of the air springs on a given
slide are pressurized through the single hose 81, a quick
disconnect is used to release the air pressure to all of the finger
operating springs. However, after the adjustment is completed, the
springs can be again pressurized by merely reconnecting the hose
81.
In some instances, a different type of transfer finger assembly is
required for the manufacture of a particular type of work piece.
For example, when the machine is used for the manufacture of headed
articles or relatively long articles which do not require any
turning during transfer, a transfer gripper of the type illustrated
in FIG. 8 may be used. Such transfer fingers again provide opposed
gripper finger elements 161 and 162 which are pivotally supported
on a slide (not illustrated) and are biased toward their closed or
gripping position by a pneumatic spring 163.
Finger opening and closing is controlled by the same cam driven
linkage illustrated in FIG. 5. Since the linkage is the same,
similar reference numerals apply to the various elements. In the
transfer illustrated in FIG. 8, however, the follower arm 164
extends to the right and is provided with a cam follower 166 which
engages the lateral bar 96. When the cam 82 causes downward
movement of the bar 96 a follower arm 164 is caused to rotate in a
clockwise direction. This produces an opening movement of the two
fingers 161 and 162 against the action of the spring 163.
Conversely, when upward movement of the bar 96 occurs in response
to the movement of the cam 82, the spring 163 causes the fingers to
close for gripping a blank. Because the follower arm 164 extends to
the right in the transfer illustrated in FIG. 8 which is the
opposite direction of the extension of the follower arm 98 of the
transfer illustrated in FIG. 5, the five cams 82 on the cam shaft
26 to the right as viewed in FIG. 1 operate the gripper fingers and
the cam 82 at the left end of the cam shaft does not function.
Transfers of the type illustrated in FIG. 8 are preferred when
transferring articles which are headed at their ends such as bolt
blanks or the like, since the fingers can be opened wider than the
fingers of the type illustrated in FIGS. 6 and 7. The transfer
illustrated in FIG. 8 does not permit turning of the blank during
the transfer operation. In most instances, when turning is not
required, the pivoting of the frame 18 is also not required. When
this condition exists, the bolts 118 are removed to allow the
follower arm 113 to be pivoted up away from the cam 111. By this
simple expediency, the mechanism for pivoting the pivot frame 18
can be rendered inoperative. On the other hand, when pivoting of
the pivot frame 18 is required, reconnecting of the follower arm
113 by means of the bolts 118 is easily accomplished.
The slide supporting the type of fingers illustrated in FIG. 8 can
be installed easily or removed in the same manner as the slide 22.
In practice, the slide is merely moved along the guideways to the
installed position and is connected at its end by the drive link
156. Here again, the slide is preferably provided with axial
passage along which air under pressure is supplied to a position
adjacent to each of the springs 163. These springs are connected to
individual hoses 166 to the passage in the supporting slide.
When the transferring is equipped with gripper finger assemblies of
the type illustrated in FIGS. 6 and 7, the various cams are
arranged so that the slide 22 is at one extreme position of its
movement and the fingers are located adjacent to the pickup or
gripping position. At this time, the pivoted frame is in the
position illustrated in FIG. 3 and the gripper fingers are
positioned immediately adjacent to the die station at which
gripping is required. When the blank or work piece is ejected from
the die into the fingers, the cams 82 allow the fingers to close
and grip the blank. The cam 111 then operates to pivot the pivot
frame 18 up around its pivot axis 21 as the slide 22 commences to
move lengthwise of the transfer toward the delivery position. By
pivoting the frame 18 up from the position of FIG. 3, the fingers
are moved away from the face of the die breast 34 to provide
clearance so that the fingers can be rotated. When the slide
reaches its other extreme of movement, the fingers are positioned
adjacent to the delivery position or die station and the cam 111
allows the pivot frame 18 to return to its initial condition. At
this time the fingers are adjacent to the subsequent die station or
delivery position and the blank is then moved by the associated
tool into the subsequent die. As this occurs, the cams 82 function
to open the fingers to release the work piece and to clear the
tool. Since all of the three drives of the transfer are powered by
the main machine drive, the operation of the three drives is
synchronized with the operation of the machine and with the
operation of the other drives.
Because a machine incorporating this invention can be easily
modified to provide a transfer system operable to transfer
different types of parts, the machine can be used to manufacture a
large variety of work pieces. Therefore, it is not necessary to
have several different types of machines to obtain the ability to
manufacture a large variety of parts.
Although preferred embodiments of this invention are illustrated it
is to be understood that various modifications and rearrangements
of parts may be resorted to without departing from the scope of the
invention disclosed and claimed herein.
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