US2643715A - Cutting die mounting and ejector - Google Patents

Description

June 30, 1953 J. E. MccLELLAN CUTTING DIE MOUNTING AND EJECTOR Filed Jupe 1o. 1948 nnnnnnn u [EN Patented June 30, 1953 UNITED STATES CUTTING'DIE MOUNTINGAND EJECTGR Joseph E. McClellan, Oakland, Calif., assigner to` himself and La Verne S. McClellan, Oakland, Calif., as joint tenants Application June 10, 1948, Serial No. 32,097

The invention relates to a die for cutting blank pieces from leather and other homogeneous brous sheet materials. i

The primary object of' the invention is to provide a die set which is operative to effective a clean cutting of fibrcussheet-material, and particularly leather.

Another object ofthe invention is to provide a` blanking die set ofthe character described in which a sheet to be cut is positivelyl gripped before and while the cutting element is applied.

A further Objectis toprovide a die-set of the character described which is particularly adapted for its mounting in, and actuation by, a stamping machine having a power-controlled plunger which is reciprocativewith respect to a bolster o1' bed of the machine.

' The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth' or be apparent in the following description thereof, and in theaccompanying drawings, in which,

Figure l is a side elevation of a machine mounting the die set, lthev diiferent` die assemblies being mutually separated to their limit.

- Figure 2 is a plan. view of the die setV taken at the line 2 -2 in Figure 1', portions of the structure being broken away.

Figure 3 is a vertical section of the die set taken at a plane through theline 3 3 of Figure 2, the co-operating die assemblies being separated asin'Figure 1.

Figure 4 is an enlarged portion oflthe showing of' Figure 3 Vadjacent and across a cutting line of the die set.

Figures 5 and 6 show the die assembly sections of Figures-3 and 4 respectively, but witha presser foot device of the male die clamping a work piece against the opposed face of the die block of the female die before cutting of a blankl is effected.

Figures 7 and 8 respectively show the die assembliesiof Figures 3 and 4 asrelated lat the end of a working stroke ofthe male die.

By reason of itsv inherent structure, leather is recognized as one of the most difficult of sheet materials from which to cut blanks, particularly if the leather isl ofY the desired thickness and quality for such elements as glove and shoe-upper parts. Because the homogeneously brousfna.-

ture of leather has heretofore made its die cuti ting mechanically dilicult and vuncertain with; available dies, the practice of cutting blanks of leatherv by striking a hand-positioned cutting die having itscutting edge supporting the die upon 2 Claims. (Cl. 164-33) v 2 a sheet of leather. placed on a lead or woolen anvil face is still largely followed, even though the methodis extremely wasteful of timebecause the cut-out blanksl frequently require hand trimming, and relatively frequent sharpening or replacements of the cutting element and/or the provision ofa new.v anvil face are required. The present die set hasbeen` sov designedv as to. eliminate the labor and mechanical difliculties of the aforesaid usuali practice, While providing for a machine operation of thevcooperative dies of a set inav speedy and effective mannery for. cutting out blanks from ash'eet of leather, or some other material of -a similar nature.

For purposes of illustration, a die set embodying the featuresof myA invention is shown as operatively associated' with a hydraulically operated blanking press H having ayC-shaped frame l2 providing a clear Working space between its: upper and lower arms I3 and'A I4 respectively. At its forward extremity, the upper frame arm I3 mounts a hydraulic cylinder I5; inY which a dou-- ble-acting pistonv 2li is operative with its piston rod I6 extending into the working. space of the frame to variable degrees in accordance with the position of its piston in the cylinder. l5, the extending rod portion carryinga cutting diev assembly l-l. The lower arm I4- of the frame:` l2 provides a bed-plate or bolster I9 on which.Y the other die assembly |8- of the die set issupported in cooperative relationto the upper die assembly I1 which is suitably held against rotation about the piston axis, or any other upright axis.

As particularly shown, the lower endz of the piston rod I6 is reduced to provide a portion i6 extending from a shoulder IG and terminating in a reduced threaded portion 16". A plate member 2| receives the piston rod. portion I6' therethrough and is arranged to constantly engagel the rod shoulder IS", said. member comprising an element of a male die assembly which primarily comprises a cutter 22 carried by a block 23 which. is in turn xed to. and beneath the platein unitary association therewith; the member 23'. has an interioropening receiving the piston rod portion l5 therethrough, and is unitarily secured tothe plate-2| by an appropriate number of screws 2@ threadedly engaging the plate, whereby it and theplate 2| comprise a base member for the Working die parts. The cutting blade 22v extends peripherally around the block 2?, isV relatively thin and of uniform thickness, is suitably xed to the block: edge as'byscrews 225, andis continuous or-effectively so, whereby itsdownwardly extending sharpenedcuttingv edge 22 defines a continuous predetermined line of cutting for the die in accordance with the peripheral outline of the block which is that of a blank to be cut.

It will now be noted that the fixed lower die assembly I8 essentially provides a continuous groove 26 which is arranged to complementarily and closely receive in its upper portion the cutting edge portion 22 of the cutting blade 22 when the upper die assembly I1 is in its fully lowered position. For providing the groove 26,

the present lower die assembly |6 comprises a base plate 21 mounting an inner die block member 28 having its periphery defining the inner wall of the groove 26, and an outer die block member 26 encircling the member 28 and having its bore dening the outer wall of the groove 26. The upper faces of the members 21 and 28 are flat and mutually coplanar and cooperatively provide the support face for a work-piece sheet L of leather, or other sheet material to be cut. Preferably, and as shown, the sharpened edge 22' of the cutting blade 22 is bevelled inwardly therearound, and the right-angle edge 29' provided at the top of the bore of the outer die block member 29 comprises and is utilized as a shearing edge in cooperation with the cutting edge 22 of the blade. Bolts 3| extending upwardly through the base member 21 into the members 28 and 29 fix the latter members to the base to provide the groove 26.

To facilitate an appropriate positioning of the inner block member 28 for receiving the bolts 3| which secure it to the base plate 21, the mutually opposed faces of the member and base may be complementarily stepped at their portions within the line of the bolts 3|. Also, a groove 21 may extend from the upper face of the base member 21 in registration with the groove 26, the groove 21' providing a, receptacle for small particles of the cut material which may descend through the groove 26. The described lower die assembly I8 may have its base 21 fixed to the bed plate I8 of the press in any suitable manner and following its setting to register its groove 26 with the lowered cutting blade 22 of the complementary die assembly |1 which is to coact with it.

Though a downward movement of the cutter 22 against a piece of material L supported beneath it upon the positioned die plate 28-29 and into the groove 26 is designed to effect a shearing cut through the material between the edges 22' and 29' respectively of the cutter 22 and the outer die block 29, it has been found that a clean `cutting of fibrous and laterally stretchable material such as leather may not be assured by such an operation of the die set so far described. The aforesaid difficulty has been overcome in the lpresent die set by providing a means for clamping a, work piece L against the die plate 28-29, and adjacent the line of cut, before and while the cutter engages the material in cutting and return strokes thereof; the present work-holding means comprises a presser-foot carried by the movable assembly |1 and appropriately cooperative with the xed assembly i8.

Noting that the cutting blade 22 extends appreciably below the block 23 which mounts it and defines a blade-bounded space of uniform bore extending beyond the lower face of'said block as the line of reciprocation of the assembly |1, a member 32 vis slidably mounted in said bore and on the reduced piston rod portion I6' for a limited reciprocative guided movement between a normal position in which it extends beyond the cutting edge 22 to a position in which the cutting edge 22' extends beyond its lower face 32. The present member 32 is recessed from below to provide a cavity 34 below its hole which receives the piston rod portion I6', and a nut 33 xedly mounted on the threaded end |6 of the rod |6 engages the inner end of the recess and functions solely as a radial stop flange to limit a lowering of the member 32 with respect to the overlying blade-carrying block 23.

The member 32 is normally held seated upon the top of the nut 33 by the action of a suitable number of helical compression springs 35 interposed in a line thereof between the member and block; in the present structure, the springs 35 extend from seats upon the top of the member 32 to the bottoms of downwardly-opening sockets 36 provided in the block 23. The screws 24 which fix the block 23 on the base plate 2| extend from the bottoms of the sockets 36 whereby their heads provide the spring seats of the sockets. Noting that the end face 32 of the member 32 is arranged to seat upon the work piece L while the cutter 22 is operatively advanced beyond it, the cavity 34 is deep enough to permit the limiting extension of the cutter beyond the member without engaging the lower piston rod extremity or the nut 33 with the work piece; as particularly shown, an upper portion 32" of the member 32 in alignment with the cavity 34 is offset upwardly to provide for the desired constant disposal of the piston rod end |6"' and the nut 33 thereon within the cavity. The portion 32" of the member 32 is arranged for its free disposal in a recess 23' extending into the blade-carrying block 23 from its under side whenever the member 32 is displaced upwardly with respect to the block 23; the arrangement is designed to provide a maximum clearance between the fully raised cutting die assembly |1 and the fixed lower die I8, whereby to facilitate the appropriate manual positioning of a work-piece for the operation of the die set against it.

A member 31 receives and is slidable on the cutting blade 22, and is arranged for substantially the same limited reciprocative movement with respect to the blade as the member 32. Bolts 38 extend upwardly from the member 31 and slidably through holes 39 provided in the plate 2|, said bolts having their heads 38 disposed above the plate 2| for supporting the member 31 therefrom in limited spaced adjusted relation thereto. A line of helical springs 4| encircles the bolts 38 and said springs having their upper and lower ends respectively seated at the end face of the plate 2| and the bottoms ofseat sockets 42 extending into the member 31 at the bolts 38, the arrangement being such that the member 31 is displaceable toward the plate 2| against the joint resistance of the set of springs 4|. It is to be noted that the threaded engagement of the bolts 38 in the member 31 permits an adjustment of this member with respect to the corresponding inner member 32 when the members are in their limiting extended positions with respect to the blade 22.

' It will now be noted that the lower faces 32 and 31 of the respective members 32 and 31 are at and are arranged to be normally coplanar, whereby they'may simultaneously engage the upper vface of a sheet L at the portion to be cut from it as a blank. Since sheets of leather and other materials to be cut may not be of absolutely uniform thickness, it is preferable that the under face of the member 32'be recessed from positive gripping ofb a sheet-'L immediately adjacentthe cutting line when the member is projected' against the sheet. While the faces 32 and 3'1"V engage the top of a work-piece sheet L, a lowering of the unitarycutter assembly I-'Iis'arranged to provide a shearing cut ofthe material at the edge 29 of the-die block 29v by the cutting edge-22 ofthe blade 22; if the material L is of leather or other homogenous iibrous material', the workingn application of the cutting blade must 'berelativelyrapid. Noting that the membersaZ and 3i aredisposable to resiliently grip a sheet L between them andY the upper faces of the op.- posed die block members 28- and 291 respectively, it-will be understood that the members32zand- 3l function as mutually independent presser. feet within and without the blade 2'2, andi comprise independentlyy operativesections of a presser foot assembly-SZ-'lv which encloses and'is guidedon 'the cutting blade 22 fora working projection of -theblade beyond the faces 32 and 3l of the respective sections 32 and 31 in working and return strokes while the latter sections. clamp a work-piece to the respective die blocks 28 and 29 as a work-holding means.

While I have herein described the disclosed cutting die assembly Ihaving presser feet. as being cooperative with the fixed` die block assembly I3, it will be understood that this assembly may operate with reasonable efficiency against a worlrpiece placedY on a fixed lead or wooden anvil face in'lieu of a die block assembly such as that presently provided. It will also'be noted that either of the presser feet 32 or 3l may be provided and utilizedalong, though their joint use will usually be preferred in the cutting of leather andother relatively soft fibrous materials. Also, in an arrangement such as the present cutter die assembly, the springs behind the presser feet 32' and 3l' assure a positive and progressively increasing pressure ofthe feet against a work-piece sheet L as. the cutting blade moves through andbeyond the sheet for its cutting of-a blank therefrom.

Referring now to the actuation of the piston rod I5 to effect working .and return strokes of the cutting die assembly il, means are preferably provided whereby successive cutting cycles may be provided in a semi-automatic manner. As generally indicated in Figure l, the operating fluid for the piston 2!! of the piston rod IE is arranged to be alternately supplied to and relieved from the upper and lower cylinder ends through pipes or ducts It and 45 which are alternatively connected to iiuid pressure and returnpipes 4E and 41, and the fluid flow is arranged to be controlled by a suitable valve-mechanism provided in a casing 4B and controllable in accordance with the setting of a rotary spindle or stem member 5l extending from the casing 48 and mounting control arms 52 and 53 which extend generally horizontally and oppositely in fore-and-aft relation to the machine frame I2. A link 5A extends from the arm 52 to a hinged connection with -an intermediate point of a setting lever 55 which extends forwardly along a side of the frame l2 from a pivot 5B at its rear end. A forward end portion 55 of the lever 52 is disposed within ready reachof an operator at the front of the machine, and comprises a pedal in the present instance.

In its forward end, the arm 53 of the control member 5I is provided with an upright opening 53 through which an upright arm portion 5l of justably'- xed toV the piston rodi I 6 vjust above the die platemember 2 I, as byv a suitable clamp58, and therod portion 51! is reciprocably engagedlin an upright guideway provided -onthe frame IZ' at a point below the range-of action of.A the valve control arm 53'. To effect its functioning in a manner hereinafter brought out; a stop member 59is adjustably'mounted onthe upright shipper rod portion 57" and is arranged to engage the top of the control arm53when the rod 5l is sufficiently-lowered with respect to the positioned'saidfarm;

therod and piston arenormally heldfully raised by reason ofthe connection of theA cylinder botitomwith the pressure pipe tithrough thel control valve and theduct-.. It will be noted that'the shipper rod arm 51" is constantly operative to prevent a rotation ofthe piston rod, andthe die assembly I'I carried by it, whereby the cooperative alignment of the upper and lower die assembliesvk is maintained.

Figure l indicates by the RomanV numerals'III andl V and VII- the positionsv of the piston, 2.0 when the die assembly Il is in its position'of Fig:- ures 3 and 5 and 7 respectively. When a work.- piece sheet L of material to be cut has been-placed in appropriate position upon the lower die assem'.- bly I8 while the movable die assembly Il is in its normal limiting raised position, a depression, of the pedal 52 is arranged to rotate the valvestem llt tovset the control valvefor supplying liquid from the supply pipe t6 to the top of the cylinder while connecting the lower cylinder portion with the return pipe Il? for effecting the lowering of the die assembly Il toward the work-piece L to finally engage the bottom faces ofthe presserfoot sections 32 and 3l with theV work-piece, after which a continued lowering-of the piston rod under the liquid pressure is operative to effect a cutting projection of the blade 22` beyond the presser feet and through and beyond the workpiece.

As the die assembly I' approaches its limiting lowered position, the valve control arm 53. is moved toward its normal position by reason of the engagement of the shipper rod block 59 therewith, and when the arm reaches said position, the liquid connections for the top and bottom of thelcylinder are automatically vrestored to their 1n1t1al conditions for a-repetition of the cutting application of the die assembly Il the next time the pedal 55 is depressed. The control-valvev functioning is preferably such that the movement of 'the cutter assembly I1 to engage its presser foot parts 32 and 31 with a sheet L is relatively slow, the subsequent working projection of the cutter beyond the presser foot is relatively rapid to provide a snap severing of a blank from the sheet, and the final automatic return-stroke lifting o f the die assembly to its normal raised position 1s preferably relatively fast to minimize the time required between operative cycles.

It will now be noted that the present die sets II-I are formed and cooperative to cut out a thumb-piece blank for a glove, and that correspondingly constructed die sets may be provided for cutting out the other blanks for the glove.

since the provision of different blanks for use 1n the assemblies of gloves and shoe uppers requires the use of different die sets I'I--I8 for hide, the clearance between the normally separated die assemblies in this machine must be suiicient to facilitate a manual positioning and repositioning of the work sheet for cutting of a plurality of blanks from it.

From the foregoing description taken in connection with the accompanying drawings, the features and advantages of the presentV cutting die and its operative application will be readily understood by those skilled in the art to which the invention appertains. While I have shown and described a structure which I now consider to comprise a preferred embodiment of my invention, I desire to have it understood that the showings are primarily illustrative, and that such changes and developments may be made, when desired, as fall within the scope of the following claims.

I claim:

1` In a machine for cutting blanks from workpieces of fibrous sheet material, a support member carried by the machine for its axial reciprocation toward and from the workpiece and comprising a rod mounting a nut at an end thereof and providing a shoulder opposite said nut in spaced facing relation thereto, and a cutting die comprising a base member intermediately aind slidably receiving the rod portion between the shoulder and nut and normally seated against the shoulder, a continuous cutting blade extending iixedly from said base member, a presser-foot member having a forward face for engaging the opposed face of a work-piece and normally having its forward face disposed beyond the blade edge, said presser-foot member being reciprocable within the blade-bounded space of the blade and slidably receiving the rod portion between the base member and the nut and being displaceable along said rod portion toward the base member to a limiting position in which it contacts the base member and being provided with a recess extending inwardly from its forward face for constantly and freely receiving the nut, and means yieldingly urging a mutual separation of the base and presser-foot members to a limit imposed by the shoulder and nut of the rod.

2. In a machine for transversely cutting blanks from a Work-piece of sheet material, a support member carried by the machine for its axial reciprocation toward and from the workpiece and comprising a rod providing a radial stop at an end thereof and providing a shoulder opposite said stop in spaced facing relation thereto, and a cutting die comprising a base member intermediately and slidably receiving the rod portion between the shoulder and stop and normally seated against the shoulder, a cutting blade extending xedly from said base member, a presserfoot member having a forward face for engaging the opposed face of a work-piece and normally having its forward face disposed beyond the blade edge, said presser-foot memberrbeing reciprocable with respect to the blade and slidably receiving the rod portion between the base member and the stop at the rod end and being movable along said rod portion toward the base member and being provided with a recess extending inwardly from its forward face for constantly and freely receiving the stop, and means yieldingly urging a mutual separation of the base and presser-foot members to a limit imposed by the shoulder and stop of the rod.

JOSEPH E. MCCLEILAN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 22,873 Howard et al Feb. 8, 1859 334,554 Allstatter Jan. 19, 1886 625,789 McBeth May 30, 1899 1,245,059 Strand Oct. 30, 1917 1,283,250 Mayle Oct. 29, 1918 1,303,680 Kent May 13, 1919 1,430,373 Hennings Sept. 26, 1922 2,412,066 Shear Dec. 3, 1946

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