US3673908A

US3673908A - Quick-change tooling for fineblanking presses

Info

Publication number: US3673908A
Application number: US108759A
Authority: US
Inventors: Roger K Smith
Original assignee: INTERN FINEBLANKING CORP
Current assignee: INTERN FINEBLANKING CORP
Priority date: 1971-01-22
Filing date: 1971-01-22
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04

Abstract

A die set is provided in which the die shoes remain essentially as part of the press and releasably retain interchangeable die members therein. Each die shoe includes locking means supported for generally lateral movement thereon and means for actuating the locking means between a locking position which positively retains a die member within a corresponding cavity in the die shoe and a retracted position which releases the die member for removal from the cavity. Each die shoe also includes ejecting means supported for generally axial movement thereon and means for actuating said ejecting means to eject the die member when the locking means is in its retracted position. The die members are formed with recess means for receiving the locking means.

Description

United States Patent Smith [54] QUICK-CHANGE TOOLING FOR FINEBLANKING PRESSES [72] Inventor: Roger K. Smith, Enon, Ohio [73] Assignee: International Fineblanking Corporation,

Dayton, Ohio [22] Filed: Jan. 22, 1971 [21] Appl.No.: 108,759

[451 July 4, 1972 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney-Marechal, Biebel, French & Bugg [57] ABSTRACT A die set is provided in which the die shoes remain essentially as part of the press and releasably retain interchangeable die members therein. Each die shoe includes locking means supported for generally lateral movement thereon and means for actuating the locking means between a locking position which positively retains a die member within a corresponding cavity in the die shoe and a retracted position which releases the die member for removal from the cavity. Each die shoe also includes ejecting means supported for generally axial movement thereon and means for actuating said ejecting means to eject the die member when the locking means is in its retracted position. The die members are formed with recess means for receiving the locking means.

15 Claims, 4 Drawing Figures SHEET 10F.2

6 z xwmw P'A'TENTEDJUL 4 m2 INVENTOI? ROGER K. SMITH ATTORNEYS QUICK-CHANGE TOOLING FOR FINEBLANKING PRESSES BACKGROUND OF THE INVENTION .The art of fineblanking requires special die sets and a special press. The die sets include die details, such as die members, a punch and punch base, an ejector and backup plate, pressure pins, pierce punch, etc., and all these details are disposed within die shoes hydraulically supported on movable tables located at positions above and below a movable strip of metal stock. In the fineblanking presses developed for the fineblanking process, such as the Osterwalder fineblanking press made in Switzerland by Feintool AG, the lower table exerts a clamping" force in an upward direction and a second opposing" force is exerted through the upper table in the downward direction.

The clamping and opposing pressures positively clamp the metal stock between the ejector and the lower die member for the blanking stroke. A mechanical ram strokes upwardly from the bottom of the press and exerts a blanking" force against a sliding punch disposed within the lower die shoe. The punch blanks the part into a cavity within the upper die member but, due to the close tolerance requirements, neither enters nor touches the upper die member.

During the blanking stroke, the punch moves about three times slower than in conventional blanking operations, and essentially squeezes the metal into parts having smooth edges, highly accurate contours and holes, and extremely close tolerances. Thus, the primary advantage of fineblanked parts is that they do not require additional processing, such as shaving, broaching, coining, reaming or drilling, and the parts are generally ready for use immediately.

Several problems have been encountered with the fineblanking tooling presently in use. The tooling must be aligned precisely to meet the close tolerances required, and consequently the die block (upper die member) and the stripper plate (lower die member) must be rigidly retained within their respective die shoes. This is generally accomplished by bolting or similarly securing the die block and stripper plate directly to their corresponding die shoes.

The problem that results is that the entire die set, including the die shoes, must be completely dismantled and removed from the press every time a part must be repaired. This creates considerable down time, on the order of 1% to 2 hours, because extra care must be taken in fastening the parts together in precise alignment. As a result, valuable production time is wasted.

Another problem is that parts processors must purchase or build a complete die set for each different part to be blanked. This creates an excessively high tooling expense. In fact, because they must purchase or obtain tooling for every order, the initial expense for processors who have a large number of low quantity orders is almost prohibitive.

SUMMARY OF THE INVENTION The present invention is directed to quick-change tooling for fineblanking presses. In general, the tooling of the present invention provides die shoes which remain essentially as part of the press and means in the die shoes for releasably retaining die members therein to facilitate their quick interchangement within the die shoes. The invention substantially reduces tooling cost, and substantially reduces the time required to change tooling in the press.

Generally, the tooling comprises locking means supported for generally lateral movement on each die shoe between a locking position which positively retains the corresponding die member within a corresponding cavity in the die shoe and a retracted position which releases the die member for removal from the cavity. The invention also includes ejecting means supported for generally axial movement on each die shoe and positioned to dislodge the die member from the cavity after the locking means has been moved to its retracted position. Means are provided for actuating the locking means and the ejecting means, and preferably comprise fluid cylinder means.

In the preferred embodiment, the locking means comprises a pair of locking pins supported in lateral bores which intersect opposite sides of the die member cavity. The pins are connected to the fluid cylinder means preferably disposed within the die shoe, and are received in tight interfitting engagement within the die members by cooperating recess means therein adjacent the lateral bores. The ejecting means comprises three axial openings generally radially spaced in the die shoe and connecting three fluid cylinder means therein with the die member cavity. An ejecting rod is positioned within each opening and is actuated in the axial direction by the fluid cylinder means to lift and dislodge or eject the die member from the cavity so that it may be quickly removed and replaced with another die member. The latter die member is then locked within the cavity by the locking means for the next blanking operation.

The cooperating recess means in the tapered mating surface of each die member preferably includes a pair of chord-like slots on diametrically opposite sides of the tapered peripheral surface of the die member adjacent to and genei'ally aligned with the bores in the die shoe. The slots define internal surfaces which are preferably formed to receive the locking pins in tight interfitting engagement for positively retaining the die members within the cavity and for providing lateral stability.

The invention enables the part processor to purchase a single set of die shoes and to maintain a series of interchangeable die members and other details for processing parts with a number of difierent configurations. The processor is accordingly not forced to purchase die shoes every time he purchases a tool, and therefore the invention provides a considerable savings in tooling costs. In addition, the invention enables the processor to reduce down time for interchanging tooling, thereby affording a considerable increase in efiiciency. Hence, the tooling of the present invention, from the practical standpoint, is a significant advance in the fineblanking art.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fineblanking press, partially broken away, and showing the tooling of the present invention mounted therein;

FIG. 2 is an axial vertical sectional view of a die set mounted on upper and lower tables of the press and constructed according to the present invention, the tables being partially broken away;

FIG. 3 is a top view of a die shoe and die member taken along line 33 in FIG. 2; and

FIG. 4 is a fragmentary sectional view taken along line 4-4 in FIG. 3 and showing a locking pin disposed within a slot in the die member and within a support bearing within a lateral bore in the die shoe.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a fineblanking press 10, such as the type manufactured by Feintool AG of Switzerland and known as the Osterwalder press, includes a cast press frame 11 consisting of a lower housing 12 and an upper housing 13 connected by a pair of integral left-hand columns 14 and a pair of integral right-hand columns 15, and defining a central working chamber 16 therebetween. Strip stock S from a coil (not shown) is conveyed horizontally between the columns and through the chamber 16 by an automatic infeed unit 17 and by a cooperating automatic outfeed unit 18, slidably mounted on the left and right-hand columns respectively.

The press 10 also includes lower and upper tables 20 and 21 each of which is supported for reciprocating axial or vertical movement by hydraulic actuating units (not shown) mounted within the lower and upper housings I2 and 13. The strip stock S is blanked into parts by a die set which includes lower and

upper die shoes

22 and 23 mounted on the lower and upper tables 20 and 21 respectively. A tapered preferably frusto-conical cavity 25 is formed within each die shoe and extends in the vertical or axial direction, and a mating tapered die member or stripper plate 26 is disposed within the lower cavity 25, and a mating tapered die member or die block 27 is disposed within the upper cavity 25. As shown in FIG. 4, the degree of taper of the cavities and mating die members is with full vertical for facilitating removal of the die members from the die shoes, as described hereinafter. Both die membets are formed with axial bores or cavities 28 having configurations corresponding to the configuration of the part being blanked. For simplicity, the configurations of the cavities 28 are shown as being circular. In accordance with fineblanking practice, a vee-ring 30 is integrally formed on the upper surface of the stripper plate 26 around the outer periphery of the cavity 28 for gripping the strip stock S.

The hydraulic units move the die members 26 and 27 between an open position for advancing or feeding the strip stock S therebetween and a closed position for clamping and gripping the strip stock S, and, in accordance with general practice a pair of guide assemblies 32 consisting of ball cages, pins, and bearings maintain the die shoes in alignment. Clamping results from a clamping force exerted in the upward direction against die member 26 by the lower hydraulic unit and a second opposing" force exerted in the downward direction against the ejector 40 within the die block by the upper hydraulic unit, and these forces are asserted and reasserted during and after the blanking stroke.

A punch 33 is slidably mounted within the lower cavity 28 and is supported by a base 34 slidably disposed within a cylindrical cavity or bore 35 formed in the lower die shoe 22 concentric with the cavity 25. The base 34 seats on an adapter ring 37 recessed within the lower table 20 and is connected to a ram 38 by means of a draw bar 39. After the stock is clamped, a third mechanically operated unit (not shown) within the lower housing 12 actuates die ram 38 to exert a blanking" force on the punch base 34 which overrides the opposing pressure acting against the ejector 40 and displaces the punch 33 upwardly within the stripper plate 26, thereby blanking the part from the strip stock S upwardly into the cavity 28 within the die block 27.

The blanked part is punched or blanked against the slidable ejector 40 within the cavity 28 and having an outer configuration corresponding to that of the punch 33. As shown in FIG. 2, a pierce punch holder 41 and a back-up plate 42 are slidably disposed within a cylindrical cavity or bore 43 formed in the die shoe 23 above the die block 27, and are connected by a dowel pin 49 and are bolted to the die block 27 by bolts 44 to form a unit which is disposed within the die shoe 23. A pierce punch 45 extends through the ejector 40 and seats against the back-up plate 42. Simultaneously with the blanking of the part, the pierce punch 45 punches a slug out of the blanked part into a center hole formed within the punch 33 against an ejector pin 46 supported by an ejector bridge piece received within the base 34 and mounted on pressure pins seated on the adapter ring 37.

When the die members 26 and 27 separate and the blanking force is released, the clamping and opposing pressures are reasserted between the ejector 40 and the punch 33, and the ejector 40 ejects the blanked part from the die block 27 and the ejector pin 46 ejects the slug from the punch 33. After the part and slugs are removed, usually with air, the die set is ready for the next blanking operation.

In accordance with the present invention, each die shoe has a pair of bores 47 which extend laterally therethrough and tangentially intersect diametrically opposite sides of the corresponding tapered cavity 25. A cylindrical locking pin 48 is received within each bore 47 and is supported therein for reciprocating movement by an elongated cylindrical bearing 50 tangentially intersecting the tapered cavity 25 and by a short cylindrical guide bearing 51 adjacent the outer end of the respective bore 46. The locking pins preferably have circular cross-sections, rather than square cross-sections, for example, because comers and other sharp surfaces are susceptible to breakage under stresses encountered in blanking and ejecting. The

bearings

50 and 51 are press fitted within the bores, and, as shown in FIG. 4, bearing has an arcuate notch 52 therein which conforms the adjacent portion thereof to the tapered contour of the cavity 25.

In the preferred embodiment, the locking pins 48 are actuated by double-acting fluid cylinder means 54 including a piston 55 mounted on an elongated piston rod 58 and slidably disposed within a cylindrical bore 60 formed within the die shoe and extending into a cup-like end cap 61 secured to the die shoe by a series of bolts 62. The cap 61 is sealed to the die shoe by a gasket 63 confined within a counterbore 64 formed within the outer end of the cavity 60 for receiving an interfitting lip 65 of the cap 61. The piston rod 58 extends through an opening 66 in the end cap 61, and Orings form seals between the rod 58 and the opening 66 and between the piston 55 and the bore 60.

The locking pins 48 within each die shoe are rigidly connected to the corresponding piston rod 58 by a connecting plate 67 which has suitable holes for receiving the outer end portions of the locking pins 48 and piston rod 58. The plate 67 is tightened by lock nuts 69.

The cylinders or bores 54 are connected to a hydraulic fluid supply (not shown) preferably through a suitable four-way flow control valve, for purposes more fully apparent hereafter, and hydraulic fluid under pressure is delivered alternately to ports 70 in the end caps 61 to extend the rods 58 in a left-toright direction, and then to ports 71 through lines 72 in the die shoes to retract the rods 58 in a right-to-left direction. The connection plates 67 transmit this reciprocal movement to the locking pins 48, so that the pins extend into the cavities 25 when the rods 58 are moved to the right (shown in dotted lines to the right of notch 52) and retract out of the cavities 25 when the rods are moved to the left, (shown in dotted lines to the left of notch 52). It should be apparent that other actuating means could also be used, such as pneumatically actuated cylinders or the like.

To accomodate the locking pins 48, each of the die members 26 and 27 has recess means preferably defining a pair of laterally extending slots 74 in diametrically opposite tapered side surfaces thereof defining internal surfaces therein which are curved for receiving the cylindrical locking pins 48. Each die member is also preferably formed with an axial slot 75 (FIG, 3) which cooperates with an axially extending bore 76 in the die shoe to receive an axial dowel pin 77. The dowel pin 77 locates the die members in the cavities 25 and prevents them from rotating therein, in the same manner that dowel pins 77' locate the punch base 34 within the lower bore 36 and the pierce punch plate 41 and backup plate 42 within the upper bore 43.

As shown in FIG. 3, the slots 74 are adjacent to and aligned with the internal surface of the adjacent support bearing 50, so that the outer surfaces of the locking pins 48 mate against the curved surfaces thereof in tight interfitting engagement. In this preferred form, the slots 74 define chords in the tapered frusto-conical surfaces of the die members, and the curved surfaces of the slots 74 mate against and support the pins 48 along the entire length of these chords to provide lateral stability. This form is thus preferred over the alternate form of circumferential slots in the peripheral surfaces of the die members, because in the latter form the curved surface of the slot would mate against and support the locking pins at only two points, the tangential points of contact with the locking pins, and the slots would not provide the desired lateral stability.

In addition, in accordance with the present invention, each die

shoe

22 and 23 also includes means for ejecting the die members 26 and 27 to facilitate quick interchangement thereof. The preferred embodiment includes a series of three double acting fluid cylinder means 78 spaced at 120 intervals around the periphery of the lower cavity 36. Each fluid cylinder means 78 is similar in construction to the fluid cylinder means 54 and includes a piston 80 mounted on an elongated piston rod 82 and slidably disposed within a cylindrical bore 83 formed within the die shoe. The bore 83 is sealed by a gasket 85 confined within a counterbore 86 formed within the outer end of the bore 83 by plug member 87 connected to the die shoe. The piston rods 82 are disposed within cylindrical openings 88 connecting the bores 83 with the cavities 25, and are preferably flush with the internal shoulders 36 when the pistons 80 are in the retracted position shown in FIG. 2. O-rings form seals between the rods 82 and the openings 88 and between the pistons 80 and the bores 83.

As in the case of the fluid cylinder means 54, the fluid cylinder means 78 are connected to a hydraulic fluid supply (not shown), as by a suitable reversible flow control valve or the like, and hydraulic fluid is delivered alternately to upper manifolds 90 and then to lower manifolds 91 in the die shoes at the opposite ends thereof from the fluid cylinder means 54. The

manifolds

90 and 91 distribute the fluid through upper passages 93 and lower passages 94 in the die shoes to upper ports 95 and lower ports 96 to the bores 83. When delivered to the lower ports 96, the fluid moves the piston rods 82 upwardly to lift and dislodge or eject the die members 26 and 27 for quick interchangement. Conversely, when delivered to the upper ports 96, the fluid retracts the rods 82 within the openings 88 for insertion of die members into the cavities 25.

In operation, a suitable four way valve (not shown) connects the outer and

inner ports

70 and 71 of the fluid cylinder means 54 and the upper and

lower ports

95 and 96 to the fluid cylinder means 78 to a source of pressurized hydraulic fluid. When it is desired to interchange the die members 26 and 27 with different die members for forming parts of different configuration, the following procedure is followed.

First, the operator switches the four way valve to connect the source with ports 71, and the hydraulic fluid urges the rods 58 from right-to-left to retract the pins 48 and release the die members 26 and 27. The valve is then moved to connect the source of hydraulic fluid with the lower ports 96, and the hydraulic fluid actuates the rods 82 upwardly into the cavities 25 to dislodge and release the die members 26 and 27 from tight interfitting engagement with the cavities 25. The taper of 5 with full vertical facilitates dislodgement.

The die members 26 and 27 are then removed from the cavities 25, and the valve is moved to connect the source of hydraulic fluid with ports 95 causing the fluid to retract the piston rods 82 within the openings 88. The punch 34 and the ejector 40 are then replaced with a corresponding punch and ejector having the configuration of the next part to be blanked.

The new pair of mating tapered die members having cavities 28 corresponding to the configurations of the new punch and ejector, and having identical slots 74 and 75 therein, are then located within the cavities 25. In the final step before blanking can begin, the valve is moved to connect the fluid supply to ports 70, and the fluid actuates the rods 58 from left-to-right to extend the locking pins 48 into and through the slots 74 in the new die members where they are received by the elongated bearings 50, thereby providing lateral stability. Movement of the locking pins 48 through the slots 74 produces a bighting pressure in the downward direction which presses the die members downwardly against the internal shoulders 36 of the bores 25 to insure proper alignment and to restrain the die members from moving under the influence of high pressures in subsequent blanking and ejecting operations. In all, only about l0 minutes is required to complete the foregoing interchanging operation.

It is thus apparent from the foregoing description and accompanying drawing that die sets constructed according to the present invention provide desirable features and ad vantages. For example, the die shoes become essentially an in tegral part of the press, and enable the parts processor to purchase and accumulate a series of interchangable die members. Thus the processor does not have to buy die shoes every time he buys a tool. This not only reduces the initial and overall tooling cost, but also reduces the part cost to the customer.

Another important advantage of the invention is the savings in down time which results when the die shoes do not require changing. As pointed out above, to change the die members and their corresponding punches and ejectors requires only about ten minutes, while in previous practice a change accomplishing the same result required as must as a full 1% to 2 hours.

In addition, the quick-change tooling of the present invention enables the processor to make efficient use of his machines. For example, if a particular die member or its details should become damaged, the processor can produce another part while the damaged part is being repaired by simply installing a second set of die members. In addition, the processor may advantageously install sets of die shoes of varying size in different size presses and thereby improve his overall efficiency and flexibility.

Another feature of the invention is that the fluid cylinder means are located within the die shoes, and consequently there are no outside forces to upset the alignment. Also, contrary to previous practice, the stinger plate is essentially a free unit because it is not bolted to its corresponding die shoe, while the die block, instead of being bolted to its corresponding die shoe, is bolted to the piercing punch holder and the backup plate and these parts are removable from the die shoe as a unit.

While the forms of apparatus herein described constitutes preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. In a die set including upper and lower die shoes each having means defining a tapered cavity, a mating tapered die member disposed within each said cavity, and means supporting said die shoes for relative reciprocating axial movement of said die members between an open position for receiving strip material therebetween and a closed position for blanking parts from the strip material, the improvement for retaining and releasing each said die member within the corresponding said die shoe cavity, comprising locking means supported for generally lateral movement on each said die shoe between a locking position positively retaining the corresponding said die member within the corresponding said cavity and a retracted position releasing said die member for removal from said cavity, ejecting means supported for generally axial movement on each said die shoe and positioned to release the corresponding said die member from the corresponding said cavity when said locking means is in said retracted position, and means for actuating said locking means and said ejecting means to facilitate quick interchangement of said die members within said die shoes.

2. The die set defined in claim 1 wherein said actuating means comprises fluid cylinder means for said locking means and fluid cylinder means for said ejecting means.

3. In a die set for a fineblanking press having upper and lower die shoes each having means defining a cavity, a die member disposed within each said die shoe cavity in tightfitting relation, each said die member having an opening corresponding in shape to the part to be blanked, a punch member slidably disposed within at least one of said openings, means supporting said die shoes for relative reciprocating axial movement of said die members between an open position for receiving strip material therebetween and a closed position gripping the material, and means for moving said punch member within the corresponding said opening after said die members have moved to said closed position for blanking parts from the strip material, an improved means for retaining at least one of said die members within the corresponding said die shoe cavity, comprising locking means supported for generally lateral movement within said die shoe between a locking position positively retaining said die member within said cavity and a retracted position, means on said die shoe for actuating said locking means to release said die member for removal from said cavity, ejecting means offset laterally from the center of said cavity and supported for generally axial movement within said die shoe and positioned to press said die member from said cavity when said locking means is released, and means on said die shoe for actuating said ejecting means to facilitate quick interchangement of said die member within said die shoe.

4 The die set defined in claim 3 wherein said locking means comprises a pair of parallel bores extending laterally within said die shoe and intersecting diametrically opposite sides of said cavity, recess means in diametrically opposite sides of said die member and generally adjacent to and aligned with said bores, a pair of locking pins disposed within said bores, means connecting said actuating means to said locking pins, and said actuating means being operative to move said locking pins between a locking position within said recess means in tight interfitting engagement with said die member and a retracted position removed from said recess means in said die member.

5. The die set defined in claim 4 wherein said bores have circular cross-sections, wherein said pins have circular cross-sections, and wherein said recess means in said die members are comprise parallel slots for receiving said circular pins and for providing lateral stability.

6. The die set defined in claim 4 including bearing means positioned within each said bore adjacent said cavity for receiving and supporting said pins when in their locking positrons.

7. The die set defined in claim 3 wherein said actuating means comprises fluid cylinder means, and said fluid cylinder means includes a cylindrical bore in said die shoe which defines a circular opening therein, means forming an end cap connected to said die shoe at said opening and having a hole therein concentric with said opening, a piston rod in said bore extending through said hole in said cap, and a piston within said bore and mounted on said piston rod.

8. The die set defined in claim 3 including pin means extending axially within each said die member and the corresponding said die shoe for precisely orientating said die member within the corresponding said cavity.

9. The die set defined in claim 7 wherein said connecting means comprises a plate outboard of said die shoe and having holes therein for receiving said piston rod and said locking pins, and means for securing said piston rod and said locking pins to said plate.

10. In a die set including upper and lower die shoes each having means defining a tapered cavity, a mating tapered die member disposed within each said cavity, and means supporting said die shoes for relative reciprocating axial movement of said die members between an open position for receiving strip material therebetween and a closed position for blanking parts from the strip material, the improvement for retaining and releasing at least one of said die members from a corresponding said cavity, comprising means for locking said die member within said cavity, ejecting means supported for generally axial movement within said die shoe and positioned to move said die member within said cavity when said locking means is released, and means on said die shoe for actuating said ejecting means to facilitate quick removal of said die member from said die shoe.

11. The die set defined in claim 10 wherein said actuating means comprises fluid cylinder means, and said fluid cylinder means includes a plurality of axially extending bores in said die shoe, means for closing said bores within said die shoes, piston rods extending through said bores, and pistons disposed within said bores and mounted on said piston rods.

12. The die set defined in claim 11 wherein three of said bores and corresponding said pistons are uniformly spaced within said shoe.

13. In a die set for use in a fineblanking press and including upper and lower die shoes each having means defining an upper tapered cavity and a lower cylindrical cavity, a mating tapered die member dis sed within each said tapered cavity, a sliding punch assemb y disposed within said lower cylindncal cavity of said lower die shoe, means supporting said die shoes within said machine for relative reciprocating axial movement of said die members between an open position for receiving strip material therebetween and a closed position for clamping said strip material therebetween, and ram means for actuating said punch assembly to blank parts from said clamped material, the improvement for retaining and releasing at least one said die members within the corresponding said die shoe cavity, comprising a pair of bores extending laterally in at least one said die shoe and intersecting said tapered cavity therein on diametrically opposite sides thereof, a locking pin disposed within each said bore, recess means in diametrically opposite sides of said die member and having curved surfaces adjacent to and aligned with said bores in said die shoe, means extending laterally within said die shoe for actuating said pins within said bores, said actuating means being effective to move said pins between a locking position within said recess means in said die member for positively retaining said die member within its corresponding said cavity and retracted position releasing said die member from said cavity, openings extending axially in said die shoe and communicating with said tapered cavity, ejecting members disposed within said openings, and means within said die shoe for actuating said ejecting members to lift and eject said die member in said tapered cavity when said locking pins are in their retracted position to facilitate quick interchangement of said die member within said die shoes.

14. In a die set for blanking parts in a fineblanking press having upper and lower die shoes, each said die shoe including means defining an upper tapered cavity and a lower cylindrical cavity therein, a cooperating punch member for each die shoe each having the configuration of the part being punched, a pair of bores extending laterally in at least one said die shoe and intersecting said tapered cavity therein generally tangentially on diametrically opposite sides thereof, a locking pin slidably disposed within each said bore, and means on said die shoe for actuating said pins within said bores between an extended position within the corresponding said cavity and a retracted position removed from said cavity, an improved die member adapted for quick interchangement within each of said die shoes and including a tapered surface for mating with the corresponding tapered cavity, an axial cavity having the configuration of the part being blanked for receiving one of said cooperating punch members of the same configuration, and recess means on said tapered surface in lateral alignment with said bores for receiving said locking pins when they are actuated to their extended position, said recess means being formed for receiving said pins in tight mating engagement for retaining said die member within said cavity and for maintaining the alignment of said punch members during blanking.

15. The die set defined in claim 14 wherein said recess means comprises a pair of parallel slots arranged in diametrically opposite relation within said tapered surface for receiving said pins in tight mating engagement therealong to provide lateral stability during blanking.

Claims

3. In a die set for a fineblanking press having upper and lower die shoes each having means defining a cavity, a die member disposed within each said die shoe cavity in tight-fitting relation, each said die member having an opening corresponding in shape to the part to be blanked, a punch member slidably disposed within at least one of said openings, means supporting said die shoes for relative reciprocating axial movement of said die members between an open position for receiving strip material therebetween and a closed position gripping the material, and means for moving said punch member within the corresponding said opening after said die members have moved to said closed position for blanking parts from the strip material, an improved means for retaining at least one of said die members within the corresponding said die shoe cavity, comprising locking means supported for generally lateral movement within said die shoe between a locking position positively retaining said die member within said cavity and a retracted position, means on said die shoe for actuating said locking means to release said die member for removal from said cavity, ejecting means offset laterally from the center of said cavity and supported for generally axial movement within said die shoe and positioned to press said die member from said cavity when said locking means is released, and means on said die shoe for actuating said ejecting means to facilitate quick interchangement of said die member within said die shoe.

4. The die set defined in claim 3 wherein said locking means comprises a pair of parallel bores extending laterally within said die shoe and intersecting diametrically opposite sides of said cavity, recess means in diametrically opposite sides of said die member and generally adjacent to and aligned with said bores, a pair of locking pins disposed within said bores, means connecting said actuating means to said locking pins, and said actuating means being operative to move said locking pins between a locking position within said recess means in tight interfitting engagement with said die member and a retracted position removed from said recess means in said die member.

6. The die set defined in claim 4 incluDing bearing means positioned within each said bore adjacent said cavity for receiving and supporting said pins when in their locking positions.

13. In a die set for use in a fineblanking press and including upper and lower die shoes each having means defining an upper tapered cavity and a lower cylindrical cavity, a mating tapered die member disposed within each said tapered cavity, a sliding punch assembly disposed within said lower cylindrical cavity of said lower die shoe, means supporting said die shoes within said machine for relative reciprocating axial movement of said die members between an open position for receiving strip material therebetween and a closed position for clamping said strip material therebetween, and ram means for actuating said punch assembly to blank parts from said clamped material, the improvement for retaining and releasing at least one said die members within the corresponding said die shoe cavity, comprising a pair of bores extending laterally in at least one said die shoe and intersecting said tapered cavity therein on diametrically opposite sides thereof, a locking pin disposed within each said bore, recess means in diametrically opposite sides of said die member and having curved surfaces adjacent to and aligned with said bores in said die shoe, means extending laterally within said die shoe for actuating said pins within said bores, said actuating means being effective to move said pins between a locking position within said recess means in said die member for positively retaining said die member within its corresponding said cavity and retracted position releasing said die member from said cavity, openings extending axially in said die shoe and communicating wiTh said tapered cavity, ejecting members disposed within said openings, and means within said die shoe for actuating said ejecting members to lift and eject said die member in said tapered cavity when said locking pins are in their retracted position to facilitate quick interchangement of said die member within said die shoes.