US3076644A - Workholder - Google Patents

Description

Feb. 5, 1963 M. FRIEDLAND ETAL 3,076,644

WORKHOLDER '7 Sheets-Sheet 1 Filedug. .12 1959 Feb. 5, 1963 M. FRIEDLAND ET AL 3,076,644

WORKHOLDER 7 Sheets-Sheet 2 Filed Aug. 12, l1959 QN WK Feb. 5, 1963 M. FRIEDLAND ETAL 3,076,644

/WORKHOLDER Filed Aug. 12, 1959 7 Sheets-Sheet 5 fifa' TORNEYS Feb- 5 1963 M. FRll-:DLAND ErAL 3,075,544

WORKHOLDER WORKHOLDER Feb- 5, 1963 M. FRIEDLAND v1:1- AL 3,076,644

ATTORNEYS Feb. 5, 1963 M. FBIEDLAND ETAL WORKHOLDER '7 Sheets-Sheet 7 Filed Aug. 12, 1959 Martin Friedland,

United States Patent-Utilice mld Patented Feb. 5, 1963 Philadelphia, and Frederick W. Schneider, Levittown, Pa., assignnrs to Wiedemann Machine Company, King of Prussia, Pa., a corporation of Pennsylvania p Filed Ang. I2, 1959, Ser.No. 833,315 21 Claims. V(Cl. 269-452) The present invention relates to workholders for inachine tools.

Av purpose of the inventionis to advance a workholder by a thruster and to close the jaws of the workholder by forward motion of the thruster.

A further purpose is tolock the jaws Yagainst vclosing until the' workholder carriage has fully advanced.

i at the same time lock the carriage and permit the cam collar to move forward and close the workholder jaws, re-

versing the operation on retraction.

A further purpose is to automatically releases and retract one of several worlcholders holding a worl; piece when danger of interference arises.

Further purposes appear inthe specification and in the claims.

In the drawings we have chosen to illustrate only one of the numerous embodiments in which the invention appears,` selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the'principles involved.

FIGURE l is a top plan view of one of the worlrholders of the present invention.

FIGURE 2 is a `fragmentary side elevation of the Workholder of FIGURE l.

FIGURE 3 is a fragmentary enlarged section on the line 3-3 of "FIGURE 1.

FIGURE 4 is an enlarged front end elevation of the workholder of the invention taken on the line 4-4 of FIGURE 2.

FIGURE 5 is an enlarged section on the line 5--5 of FIGURE 2.

FIGURE 6 is a diagrammatic fragmentary top plan view of a machine tool according to the invention, showing two of several` workholders.

FIGURE 7 is an end elevation of FlGURE y6 taken on the line 7 7.

FIGURE 8 is a central vertical section of the workholder of the invention, the section being taken on the line S-S of FIGURE 5 to reduced scale. j

FIGURES 9 to ll are views showing other positions of the `workholder of 4FIGURE 8.

FIGURE 12 is an electric circuit diagram of the device oi the invention.

voperation of machine tools, especially turret Ipunch press gauging tables, there is an increasing need for work- Y holders which can operate to engage and release andad vance and retract work by remote control.

Furthermore in such devices where there Aare a plurality of workholders, it may be necessary tocarry the work to a position in which an individual worlcholder vwould interfere with the machine tool or be damaged.

- 7construction `and` convenicnt'in voperation,,performing its main functions entirely under the` control lof a thruster and .of .auxiliary locking devices.

A sliding guide Ztl, suitably of box formation,` is supportedon shim pads 21 restingvon a laterally movable carriage 23. `Socket head Vcap screws 22-fextend through the carriagel and are threaded into tapped holes 22 in the sliding guide`2ll to secure thev slidingguide 20 to thelaterallyniovable carriage 23. The slidinggnide 2n l is Vlevelledon the carriage 23 byzshims 23..

A` -dowel 222 passes through holes 23' and 224 and positions the-slidingA guide `Zilrelative to the laterally movable carriage 23.

The carriage 23 has guide surfaces 25 which slide "transversely of the mach-ine tool on ways 2d which explaced `a forwardly and -backwardly-rnoving'carriage 32,

Yit

generally of'channel formation and capableof telescoping inside the sliding `guide andinioving -forward beyond `The carriage 32st the forward end has iixed thereon lowerl and upper bearing lugs 33 and 34, and on the bearing lugs are pivoted lower workholder jaw 35 and upper workholder jaw 35 on pins 3? and 318 extending through openings in the lugs and the jaws.

Threaded studs 39 and nuts 39 swivelly connect toggle r pads'i) to the 'jaws at dll.

`carries roller ypins 43 journalling cam rollers 432 which A rideon cam surfaces 433011 the top of sides 44. Pins-434 carry cam rollers 435 which ride on cam surface 436 vwhich isk onthe bottom of 'sides-44. `iii/ear strips, not

shown, Vextending in the direction of motion of the carriage,- are suitably securedv to Ythe sidesJ of the cam `collar 43 and bear against spaced sides 44 at 437. The ycam collar 43 is limited to-:sideward` motion by 'thesides 144 Y and is limited in forward motion by the stroke of the hydraulic cylinder 5l.

A tieplate 45 extends vacross-the fro-nt of the carriage and is suitably secured to'sidesdl behind the gripping lportions of the rjawspthus supporting the sides 4d together. Within thisrange .the cam collar is permitted to rnove forward and its lower' cam rollers 46 journalled onpins 46 engage successively cam surf-aces 41 and 42 on the lower surface of the lower jaw.- The upper jaw has rst and second cam surfaces i7 and llon the ,top surface which aresuccessively' engaged Vby, cam

rollers 50 journalled on pins 50' on the upper portion of the cam collar.

A locator 49 is secured to a retainer 49 by cap screws 492. The retainer 49 is of generally rectangular form with a lever receiving notch 493 and a latch extension 494. Shoulder screws 495 pass through diagonal elongated slots 496 and slidably connect the retainer 49 to the side piece 44.

A helical spring housing 497 suitably secured to side piece 44 retains helical spring 498 which urges plunger 499 which bears against retainer 49' and biases the retainer downward.

Actuator 491 slidably mounted in actuator housing 4911 is urged rearward by helical spring 4912 wound about dowel 4913 acting against spring abutment 4914 on the housing and spring abutment 4915 on the actuator biases the actuator rearward.

Actuator extension 502 slidably supports retainer 49' at 494.

Lever `4916, having perpendicularly displaced arms 5t)3 and 504, is pivotally connected to side 44 by pin 565. Arm 503 engages slot 493 on retainer 49.

A thruster, suitably a double acting hydraulic cylinder 51, is mounted at 52 at the back of the sliding guide 20, and has a piston and rod combination 53 which extends forward in the carriage. The thruster is operated by a solenoid operated hydraulic control valve 54 carrying a built in control valve which supplies hydraulic uid selectively to opposite ends of the cylinder through pipes 55 and 56. The pump and valve assembly is conveniently located on top of the sliding guide as best seen in FIG- URES 1 and 2.

At the rear of the sliding guide the housing 57 is extended down and holds suitable control equipment, as later explained.

At the forward end, the piston rod of the thruster connects with a longitudinal cam 58 which at the forward end is secured to a cross piece 66 in the cam collar. The cross piece 60 is located between the jaws 35 and 36 and the cam 58 extends through an opening between the lugs 33 and 34 located in the front of the carriage.

Cam 5S has a forward straight track 61 on both sides which corresponds to locking of the cam collar, an intermediate slope 62 on both sides and a rearward straight track 63 on both sides which corresponds to unlocking the cam collar. The cam 53 also has a stop abutment 64 at its rearward end.

The cam 58 passes through an opening in and is surrounded by a cam follower 65 having suitable approach surfaces to permit it to ride the slope of 62 and otherwise follow one of the other cam surfaces 61 or 63. i The cam follower 65 is retained in position against moving longitudinally with respect to the carriage by transverse guide pins 66 shown in FIGURES 1, 3 and 14, and has a notch 67 at one side which receives one ball end 68 of a toggle lever 70 pivoted on pin 71 intermediate its ends in the side wall of the carriage 32.

The rear end of the toggle lever 70 has a ball end 72 which engages in a notch 73 of a laterally movable locking pin '74.

The locking pin is guided by a tubular bearing 75 in the carriage and rides a track 76 in the sliding guide over a portion of the travel of the carriage. When the carriage reaches a forward position, locking pin 74 engages in hole 77 in support guide 2t] (FIGURE 3).

When the carriage moves forward to its limiting position, adjustable stop 78 on the back of the carriage engages bumper St) on the sliding guide as shown in FIG- URE 9. A trip mechanism 81 extends along the carriage 32 guided on guides 82 and extends into a slot S3 in the sliding collar. The trip mechanism d1 is fixed to and slides with carriage 32. The end of trip mechanism S1 is beveled to engage roller 101i of limit switch Miti. Roller G is spring biased by helical spring 1662. Contact is made at 10G3 when trip mechanism 81 slides away from roller 199', and contact is broken when trip mechanisrn 81 engages roller 109 and forces it upward.

The cam collar 43 has pins 84 and 85 which engage the insides of the gripping jaws. When the collar is retracted the pin S5 holds the upper jaw up, and the pin S4 forces the lower jaw down.

In FIGURE 12, we show an electric circuit Suitable to operate the device of the invention and including power leads 36 and 87, the latter suitably being grounded. The leads are desirably connected to a source of alternating current at 1l() volts, 60 cycles. An approach responsive device 38 is connected across between the leads and located at the bottom of the housing 57 where it can respond to approach to a danger area indicated by interference pattern (FIGURE '7) suitably placed beneath the machine. The interference pattern 9i) may suitably bc of magnetically susceptible material (such as steel) which will cause response in the approach responsive device S8. If desired, however, the device SS may be a limit switch instead of an approach responsive device.

The relay in the approach responsive device 38 has one set of normally closed contacts SS-l and one set of normally open contacts 88-2.

The normally closed contacts 33-1 are in series with one set of contacts 92 of switch 91 and one set of contacts 93 of switch 94 and with the solenoid valve 95 which tends to throw the hydraulic valve into position to advance the thruster 51 forward and clamp the work.

Thus in normal automatic operation, the solenoid is energized through contacts 92 of switch 91 and through contacts 93 of switch 94 and closed relay contacts 88-1 to move the thruster to its extreme forward position and clamp the work in the jaws.

Additional circuit units similar to those described can be connected at 99.

If the equipment (gauging table) moves to a position where the workholder is liable to be damaged by further operation of the machine, the approach responsive device S8 cornes into proximity with the pattern 90 and the relay in the approach responsive device 3S picks up, opening normally closed contacts Sii-1 and closing normally open contacts 88-2. Solenoid valve 95 is energized, throwing the hydraulic valve into the position to retract the thruster 51, open the jaws and retract the carriage. As long as the gauging table remains in the danger area, the approach responsive device remains energized and the particular workholder remains retracted, although other workholders not in the danger area are supporting the work and retaining it in the proper position.

When the gauging table moves away from the danger area, the approach responsive device is deenergized and the control relay returns to normal condition.

The hydraulic valve then is shifted by solenoid 95 to advance the workholder and grip the work.

Although one workholder may release and another take hold, this does not change the position of the work as the Iwork is being held by other worlrholders.

Thus it will be evident that when one of several workholders approaches a dangerous area, it will automatically release and then, if the danger persists sufficiently long will retract. As soon as the danger clears, the reverse operation takes place automatically. Thus, if the work moves from side to side of the machine through the turret punch press or the like, the successive workholders will release and then take hold again, but the work will always be held properly by the remaining workholders.

In manual operation, any workholder can be retracted independently of other workholders by operating switch 94 to open normally closed contacts 93 and close normally open contacts 97. This deenergizes solenoid valve 95 which urges the workholder forward and energizes solenoid valve 95 which opens and retracts the workholder.

When all worlrholders are to be clamped and unclarnped in unison this is controlled by switch 9i. If switch 93. is shifted to open contacts 92 and close contacts 98, the forward acting solenoid valve 95 will be aar/asas deener'gizesfthe retract-ing solenoid 9601i the workholder. When it is desired to'load the work in the workholder,

'switch l'9-1 is lmanually shifted to opencontacts- 92 and to close contacts tlto energize the retracting solenoid 96 on each workholder.

The workholder ljaws 35and 36 are opened by theVV collar 43 which is fbeingmoved rearward bythe thrusterl. This continues "until the trip `mechanism S1 engagesl roller Idil on limit switchltltl.

Trip mechanisrni is adiustedso that the jaws are fully t unclamped `when the `switch loll is activated, an-d this vprevents Vthe locking piddfronrbeing withdrawn. Thus the workholders are inltheirffully extended position when thework isbeingl clamped and unclamped for-loading vand unloading respectively. e

Limit switch' 101i istused in coniunction with relay -102 tov indicate whenl the workholde'r `is` retracted from the dangerV area.y When the workholder reaches the-extreme retracted position limit switch lill is closed and control relay 102 is energized. The relay ylin-remains energized aslong as'tliew'orkholdereis `in the retracted position actu- Relay '162 is thus capable of ating 'limit switch 161. providing any required interlo'cks with the machine tool.

lelrwing ynow described the operation of the electrical device,`the^operation of the workholder mechanism is as follows:

`Considering first Vthe positionof FIGURE S, with the thruster fully retracted, the follower 65 is engaging cam track6l, and the toggle leveris in the position in which pin 'M is retracted and is locked in that position by engagement with track 76. The cam follower 65 is not per- Vmitted to ride upthe cam slope`62 because of the locking from moving down by track 75 until the position of lFIGURE 9 is reached, Where Tpin 74 has'passed beyond the front of the track 76. Up to this time the cam collar has `been locked against forward motion by the pin'l'd and toggle lever 7d which are acting oncam follower 65 to hold cam' 58 against moving forward in the carriage.

At this time, locator e9 is being held in a rearward or retracted position relative to sides 44 at the forward end of carriage 32.

The locator assembly, during retraction in thefprevious cycle, was in the position shown in FIGURE 13.A When the carriage was fully retracted, actuator 4910 at its rearward end contacted the sliding guide ldan'd was pushed forward relative to the carriage 32. This caused actuator extension Sil? to slide along andV clear 'latch extension 494. Retainer 49 was free to move downward and rearward along shoulder serein/S495 under the biasing action of springe. During the advance phase, the retainer i9 is held from moving upwardly and forwardly 4relative to the carriage by actuator extension 562 engaging latch In this position, the locator is held retracted and is not in a position to bump the edge of the work sheet at the forward end of the advance phase of the cycle at the clamp position. To advance the locator to the work sheets d Thus the `locator 49 was not in position to bump the `edge of the sheet when the jaws move forward and grip, but subsequently achieves the correct position against the edge of the sheet and holds the sheet against slipping laterally.

Now as shown in FlGURES 3 and 10, pin '74 moves to locking position and positively locks the carriage in forl `ward position, while the lever 7d dellects the follower 65 upward as shown in FiGURE l0` and allows the cam'SS to move forward, the follower o5 engaging cam track 63. Cam collar d3 moves forward and lower cam rollers d( i raise the lower jaw to .horizontal 'position by ridingalong cam surface 4l and then later as shown in FIGURE ll hold the lower jaw `horizontal by engaging cam .surface 42. #In -the meantime, as the cam collar moves forward between the positions fof FIGURES 1.0` and ll, under the action of the thruster, the upper cam rollers dll on the cam collar act on rhecam surface S on the upper jaw and the upper toggle pad grips the work at ltlZ. Forward motion of cam collar d3 is limited by cam surface dd, and in turn the jaw positioniof jaws 3S and 36 is determined by the work piece being clamped. lt is evident that all thicknesses of work material withinV the capacity of the machine-may beclamped without any adjustment.

The cycle is completed by a reversal of the sequence of FIGURES 8 to l'l as described above.

The locator i9 is suitably set before the jaws closeon the work, lso as to properly locate the work withrespect to the table in its correct position.

yIt will be understood that this complete cycle will 'take place only when the individual workholder is in danger oi" interfering with the operation being done on the work piece. To load and unload 'the work in the plurality of workholders, the carriagesl are kept in a 'forward position while the jaws 35 `and`36 are in lthe'openv position'f as previously explained.

In view oi our invention and disclosure, variations and modiications to meet individual whim or particular need -will'doubtl'ess become evident to others skilled in the art, to obtain all or part of thebenelits of our invention without copying the structure shown, and we, therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

l. ln a workholder, a sliding guide, a thruster mounted on the guide, a forwardly and backwardly moving carriage slidable on the sliding guide, pivoted jaw means on the forward end of thecarriage, and caml means on the forward end of the carriage acting on the jaw means, said cam means being interconnected with the thruster, thecarn means acting on the carriage to move the carriage forward and then on the jaw means to close the jaw means, and in retraction acting on lthe jaw means 'to open the jaw means and'thcn acting on the carriage to retract the carriage.

2. A workholder of claim 1, in combination with means acting on the cam means during a portion of the stroke of the carriage to lock the-cam means'with respect means 'for locking the cam means with respect to the carriage during a predetermined portion of the travel of `the carriage and then unlocking the cam means, and means actuated by thethruster for locking `the carriage in forward position. i

5. A workholder of claim l, in which the jaw means includes swingable elements, and jaw pads swivelling on the swingable elements.

6. ln a workholder, a guide, a carriage slidabie on the guide, a thruster mounted on the guide, workholder jaw means mounted on the forward end of the carriage, and

emessa 7 adapted to open and close, cam means mounted on the forward end of the carriage and adapted to move with respect to the carriage and open and close the jaw means, second cam means on the forward end of the thruster intereonnected to the first cam means and operative on longitudinal motion of the first cam means, a follower engaging the second cam means, and means for locking the follower with respect to the second cam means and thereby preventing relative motion of the first cam means with respect to the carriage during a portion of the forward stroke.

7. A workholder of claim 6, in combination with means releasing the second cam means at a forward position of the carriage.

8. A workholder of claim 7, in combination with means operated by the second cam means for locking the carriage in forward position.

9. A workholder of claim 7, in combination with toggle means operated by the second cam means for locl'- ing the workholder in forward position.

10. A workholder of claim 7, in combination with means operated by the second cam means for releasing the first cam means, to move forward under the action of the thruster with respect to the carriage and close the jaw means.

ll. ln a workholder, a sliding guide, a thruster mounted on the guide, a carriage slidable on the sliding guide, pivoted jaw means on the forward end of the carriage, cam means on the forward end of carriage acting on the jaw eans, said cam means being -interconnected with the thruster, the cam means acting on the carriage to move the carriage forward and then on the jaw means to close the jaws means, selectively operative means to open the jaw means while the carriage is extended forward, for the purpose of loading, and means for preventing retraction of the carriage during loading.

12. A plurality of workholders adapted to engage a single piece of work at the same time, support means common to said plurality of workholders, each of said workholders comprising a sliding guide, a thruster mounted on the guide, a forwardly and backwardly moving carriage slidable on the sliding guide, pivoted jaw means on the forward end of the carriage and cam means on the forward end of the carriage acting on the jaw means, first means for moving said thruster on each of said Workholders forwardly and bacliwardly, and second means for moving a thruster of an individual workholder of said plurality of workholders backwardly when said individual workholder encroaches on a predetermined space.

13. In a workholder, a sliding guide, a carriage slidable on the guide, jaw means pivotally mounted on the front of the carriage, a cam collar surrounding the jaw means and adapted in one position to close the jaw means and in another' position to open the jaw means, a thruster operating in the direction of motion of the carriage, interconnected to the cam collar and adapted in forward position to move the cam collar with respect to the carriage and close the jaw means, second cam means interposed between the cam collar and the thruster, and means acting on the second jaw means for locking the cam collar with respect to the carriage during a portion of the forward stroke.

14. A workholder of claim 13, in combination with a follower for the second cam means, a pin on the carriage, means interconnecting the pin and the follower, and a track on the guide engaging the pin and locking the second cam means against relative motion to lock the cam collar.

15. A workholder of claim 13, in combination with means for locking the cam collar with respect to the carriage during a portion of the foiwvard motion and toggle means for locking the carriage with respect to the sliding guide in forward position and thereby releasing the cam collar for forward motion to close the jaw means.

16. In a workholder, a carriage, pivoted jaw means on the forward end of the carriage, a work locator having a forward position and a retracted position adjoining the line of meeting of the jaw means, and located on the Side of the work between the jaw means and the carriage, means for retracting the work locator to a rearward position remote from the jaw means, said means for retracting the work locator comprising spring means urging the work locator toward retracted position and latch means for holding the work locator in retracted position, means for advancing the work locator to a forward position adjoining the jaw means, and means operated by the position of the carriage for actuating the latch means to release the work locator from forward position and latch the work locator in retracted position.

17. A Workholder of claim 16, in combination with manually operable means for shifting the worlr locator from retracted position to forward position, and latch means holding the Work locator in forward position.

18. In a workholder, a sliding guide, a carriage slidably forwardly and in retraction on the guide, jaw means pivotally mounted on the front of the carriage, a cam collar surrounding the jaw means and adapted in its one position to cam the jaw means closed and in another position to cam the jaw means open, a thruster operating longitudinally of the sliding guide interconnected with a cam collar and adapted to move the cam collar independently of the motion of the carriage when the carriage is in forward position so that the motion of the thruster on the cam collar can close the jaw means.

19. A workholder of claim 18, in combination with locking means for locking the cam collar with respect to the carriage during a portion of the forward stroke.

20. In a workholdcr, a carriage, opposed pivoted jaw means on the forward end of the carriage, the jaw means being adapted to engage opposite sides of work in sheet or plate form, a work locator having a forward position in which it engages the edge of the work when it is held by the pivoted jaw means and having a retracted position remote from the work, the work locator being in line with the work when held. by the jaw means and located between the jaw means and the carriage, means for retracting the work locator to its rearward position remote from the jaw means and means for advancing the work locator to its forward position in which it engages the edge of the work when the work is held by the jaw means.

21. A worlrholder of claim 20, in which the means for retracting the work locator comprises spring means urging the work locator toward retracted position, and latch means for holding the work locator in said retracted position.

References Cited in the le of this patent

Claims (1)

1. IN A WORKHOLDER, A SLIDING GUIDE, A THRUSTER MOUNTED ON THE GUIDE, A FORWARDLY AND BACKWARDLY MOVING CARRIAGE SLIDABLE ON THE SLIDING GUIDE, PIVOTED JAW MEANS ON THE FORWARD END OF THE CARRIAGE, AND CAM MEANS ON THE FORWARD END OF THE CARRIAGE ACTING ON THE JAW MEANS, SAID CAM MEANS BEING INTERCONNECTED WITH THE THRUSTER, THE CAM MEANS ACTING ON THE CARRIAGE TO MOVE THE CARRIAGE FORWARD AND THEN ON THE JAW MEANS TO CLOSE THE JAW MEANS, AND IN RETRACTION ACTING ON THE JAW MEANS TO OPEN THE JAW MEANS AND THEN ACTING ON THE CARRIAGE TO RETRACT THE CARRIAGE.

Images