US3269168A

US3269168A - Die apparatus

Info

Publication number: US3269168A
Application number: US446759A
Authority: US
Inventors: Edward A Anderson
Original assignee: Lamson and Sessions Co
Current assignee: Russell Burdsall and Ward Corp
Priority date: 1965-03-05
Filing date: 1965-03-05
Publication date: 1966-08-30
Anticipated expiration: 1983-08-30

Description

Aug. 30, 1966 ANDERSON 3,269,163

DIE APPARATUS Original Filed July 18, 1961 3 Sheets-Sheet 1 INVENTOR. 0 wqxeo A Azvomso/v By f A rroAws Y5 Aug. 30, 1966 E. A. ANDERSON DIE APPARATUS 5 Sheets-Sheet 2 Original Filed July 18, 1961 INVENTOR. f WW0 ,4. Azvamson B mi r E. A. ANDERSON 3,269,168

DIE APPARATUS Aug. 30, 1966 5 Sheets-Sheet 5 Original Filed July 18, 1961 96 IN V EN TOR.

0 wmeo ,4. ANDE/QSON United States Patent ice 3,269,168 DIE APPARATUS Edward A. Anderson, Cleveland Heights, Uhio, assignor to The Lamson 8; Sessions Company, Cleveland, ()hio, a corporation of Ohio Continuation of abandoned application Ser. No. 290,840, June 26, 1963, which is a continuation of application Ser. No. 124,900, July 18, 1961. This application Mar. 5, 1965, Ser. No. 446,759

27 Claims. (Cl. 72412) This invention relates to die apparatus of the kind comprising co-operating punch and die members and, as one of its objects, aims to provide a novel construction for such apparatus.

This application is a continuation of application Serial No. 290,840, filed June 26, 1963, now abandoned, which in turn is a continuation of application Serial No. 124,900, filed July 18, 1961, now abandoned.

Persons skilled in the art relating to metal working dies for cold Working are aware of the fact that such dies are commonly subject to severe load conditions tending to cause rapid wear and frequent breakage, particularly of the punch member of such apparatus. When wear or breakage of the punch makes replacement thereof necessary, the machine equipped with the die apparatus is rendered idle and production time is lost.

Since the punch member has commonly been regarded as the weakest part of conventional cold working and cold extrusion dies, attempts have been made to strengthen the punch member by improving the design thereof but this has mainly resulted in punches of special shapes which are more costly to produce, both from the standpoint of forming the special shapes on the punches and from an increased amount of tool steel needed in such special-shape punches.

The wear of a punch member usually occurs at the work-engaging end thereof and, because of the characteristic non-uniform body shape heretofore used in punches, they ordinarily cannot be reconditioned for further use but must be scrapped. Since the metal used in punches is a costly tool steel, frequent replacement of punches considerably increases die costs.

This invention minimizes these problems by providing novel die apparatus which includes a punch member made from running-length tool steel bar stock and having a uniform-size and a uniform-shape transverse cross-section substantially the same as the cross-section of the bar stock, whereby the punch member can be reversed endfor-end for increasing the useful life thereof or can be reconditioned for further use by grinding one or both ends thereof.

This invention also provides novel die apparatus in which a punch member mounted in a holder means forms therewith a preformed assembly unit adapted for removable and replacement as such with respect to a supporting and actuating ram or the like, so that the changing of the punch member can be accomplished quickly and without any lengthy interruption of machine operation by merely substituting another of the punch assembly units in the machine.

This invention further provides novel die apparatus having a punch member and a holder means including a contractible clamping means for gripping the punch member around its outer periphery and along a substantial portion of its length and wherein the gripping engagement between the punch member and the clamping means is such that the gripping forces are evenly or substantially evenly distributed along and around the portion of the punch being gripped.

Additionally this invention provides novel die apparatus having a simplified form of stripper means associated with a punch member.

Patented August 30, 1966 Other objects, novel characteristics and advantages of this invention will be apparent in the following detailed description and in the accompanying drawings forming a part of this specification and in which,

FIG. 1 is a vertical axial section through die apparatus of this invention;

FIG. 2 is a transverse section taken on section line 2-2 of FIG. 1 and appearing mainly as a bottom plan view of the punch assembly of the apparatus;

FIG. 3 is a partial transverse section through the stationary or stake assembly of the apparatus and taken on section line 3-3 of FIG. 1;

FIG. 4 is a fragmentary vertical section corresponding with a portion of FIG. 1 and showing the stripper means of the apparatus on a larger scale;

FIG. 5 is a perspective view showing the punch member for the die apparatus of FIG. 1 in detached relation;

FIG. 6 is a similar perspective view showing the punch stem member of the stake assembly in a detached relation;

FIG. 7 is a vertical axial section similar to FIG. 1 but showing a modified form of the die apparatus of this invention;

FIG. 8 is a partial transverse section taken on section line 8--8 and appearing mainly as a bottom plan view of the punch assembly of the modified apparatus;

FIG. 9 is a partial transverse section taken on section line 9-9 of the stationary or stake assembly of the modified apparatus;

FIG. 10 is a perspective view in detached relation of the punch member of the modified apparatus; and

FIG. 11 is a similar perspective view showing the punch stem member of the stake assembly of the modified apparatus.

The novel die apparatus 10 of this invention is shown in FIG. 1 as comprising, in general, a punch assembly 11 carrying a punch member 12, and a stationary or socalled stake assembly 13 having a die member 14 with which the punch member 12 cooperates in imparting a desired shape, by cold working, to a workpiece 15 located in the die cavity 16 of the die member.

The punch assembly 11 is movable in closing and opening directions relative to the stake assembly 13 by being mounted on a movable carrier 18 which, in this case, is adapted to be connected with the reciprocable ram of a fabricating machine such as a punch press or the like (not shown). The stake assembly 13 is mounted on a stationary support such as a bolster plate 19 received on the support surface 26 of the bed portion 21 of the fabricating machine.

The punch assembly 11 comprises a hollow punch holder member 23 having a cylindrical recess 24 extending axially thereinto from the lower end thereof, and contractible clamping means 25 in the recess for gripping co-operation with the punch member 12. The holder member 23 is here shown as being a drum-shaped member having an annular side wall portion 26 whose inner surface forms the cylindrical side wall 24* of the recess 24. The holder member 23 also has a transverse wall portion 27 at the upper end thereof carrying a surface forming the inner end wall 24' of the recess.

The contractible clamping means 25 is of a truncatedcone shape and has a central axial passage 28 in which the punch member 12 is snugly received. The clamping means 25 is disposed in the recess 24 with the large inner end thereof seating against the transverse end wall 24* and with the small outer end thereof facing toward the die member 14. The clamping means 25 is located in a central position in the recess 24 with an intervening annular space between this clamping means and the cylindrical internal side wall 24 in which a wedge means 30 is received.

The wedge means 30 is here shown as comprising an annular ring member having a cylindrical outer side wall lying against the internal side wall 24" and is of an axial length so that these engaged side walls are substantially co-extensive. The clamping means 25 and the wedge means 30 have co-operating annular surfaces 31 and 32 on their adjacent sides which are tapered surfaces, here shown as locking tapers, extending in an axially inward diverging relation relative to and along the common central axis 33 of the holder member 23 and the recess 24. The wedge means 30 is here shown as being connected with the holder member 23 and retained within the recess 24 by suitable screws 35 extending through the wedge means and effective thereon to draw the same axially into the recess 24.

The clamping means 25 is here shown as being a single part, that is, a one-piece member, which is split longitudinally along one side thereof as indicated by the crevice 36 and has limited flexibility rendering the same contractible along its axial length for gripping the punch member 12 around its outer periphery or sides in response to an inward wedging action produced by the co-operating tapered surfaces 31 and 32 when the wedge means 30 is drawn into the recess 24 by the screws 35. The contraction or closing movement of the clamping means 25 around the punch 12 is equal or substantially equal along its axial length to apply an equal or substantially equal gripping force on the sides of the punch 12 along that portion of its length disposed within the passage 28.

The punch member 12 has a substantial portion of its length, at least fifty percent of its length, as shown in FIG. 1, received in the passage 28 and gripped by the clamping means 25, and with another portion thereof projecting from the holder member 23 for movement into the die recess 16. The projecting punch portion extends through stripper means 37 which will be presently described. The inner and outer end portions of the punch member 12 comprise

end thrust portions

12 and 12 thereon and, in this case, these end portions have flat transverse end surfaces. The punch member 12 is here shown as being cylindrical in cross-sectional shape for the full length thereof between

such end portions

12 and 12 and the passage 28 of the clamping means 25 is likewise of a cylindrical shape.

An important feature of this invention is that the punch member 12 comprises a single straight piece of tool steel bar stock and has a uniform-shape and uniform-size transverse cross-section which is substantially the same as the transverse cross-section of the bar stock. When the punch member 12 has this uniform-shape and uniform-size transverse cross-section for the full length thereof between the end thrust portions 12 and 12', the punch member can be formed by cutting from tool steel bar stock of the given transverse size and shape a straight piece of the predetermined length needed for the punch member.

In this case the workpiece 15, as shown in FIGS. 1 and 4, has a socket-shaped cylindrical body portion 15 with a cylindrical recess therein and a forked lower end portion 15 and, so far as the requirements of this workpiece are concerned, the punch member 12 need have only the above-mentioned flat surfaces on the

end portions

12 and 12 thereof. The end portions 12* and 12 can therefore be of the same cylindrical size and shape as the intermediate portion of the punch member, and consequently, since the punch member is of the uniform-size and uniform-shape cross-section mentioned above, it can be reversed end-for-end when wear or breakage occurs at the work-engaging end portion 12*. In this way increased life for the punch member 12 is obtained when this member is of this uniform-shape and uniform-size cross-section and this is an advantage not previously obtainable with punch members of the special shapes generally used heretofore.

The punch member 12 is shown in FIG. 1 with the end portion 12 thereof seating against an insert member 38 provided in the punch assembly 11 in a back-up relation to the punch member. The insert member 38 comprises a short length of tool steel bar stock of the same transverse cross-sectional size and shape as the tool steel bar stock comprising the punch member 12. The insert member 38 can, if desired, seat directly against the transverse end wall 24 but preferably as here shown, abuts against a hardened disk 39 recessed into the transverse wall portion 27 of the holder member 23.

From the construction described above for the punch member 12 and the mounting thereof in the punch assembly 11, it will now be recognized that the punch member is not only reversible end-for-end for prolonging the useful life thereof but the

end portion

12 and 12 can :be. reconditioned by grinding thereof, when needed, to thereby further lengthen the useful life of the punch member. The shortening of the punch member 12, which occurs as the result of such grinding thereof for reconditioning the

end portions

12 and 12 is compensated for by the length of the insert member 38. The length of the insert member 38 is selected so that, for any punch member 12 which has been thus shortened by reconditioning of one or both end portions thereof, the added length of the insert member will restore the punch member to a full length condition. When the punch member 12 is initially of the proper length, the insert member 38 is omitted and the end portion 12* seats directly against the disk 39.

The stripper means 37 comprises a combined die sleeve and stripper member 41 (see FIG. 4) disposed in a surrounding relation to the punch member 12, and stripper actuating pins 42 and 43 extending axially through

passages

44 and 45 of the clamping means 2-5. The

pins

42 and 43 have

heads

42 and 43 on the upper ends thereof which operate in axial passages 46 of the holder member transverse wall 27 and prevent the pins from dropping out of the

passages

44 and 45. The lower end portions of the

pins

42 and 43 project from the clamping means 25 and are provided with

notches

42 and 43 in the adjacent sides thereof. The stripper member 41 is here shown as comprising a die sleeve 41 and a lateral flange 41 around the upper end of such sleeve.

The stripper means 37 is provided with enlargement means 47 at the upper end thereof as a support portion of the stripper member 41 and which is received in the

notches

42 and 43 for connecting the stripper member with the stripper actuating pins 42 and 43. The enlargement means 47 is here shown as comprising upper and

lower ring members

47 and 47 surrounding the punch member 12 and having the annular flange 41 of the stripper member 41 received therebetween. The opening of the lower ring member 47 is of a sufliciently large transverse dimension to accommodate the die sleeve 41 In addition to forming a stripper member, the part 41 also acts as a die member by movement of the sleeve 41 part way into the die recess 16, as shown in FIGS. 1 and 4, when the die apparatus 10 is in its closed condition. The lower end of the sleeve 41 is of a size and shape suitable for performing a desired forming operation on the upper end of the workpiece 15 and, in this case, has an annular lip 49 thereon which is effective on the workpiece to form a desired counter-recess or chamfer 50 around the inside of the upper end of the workpiece opening. The stripper member 41, when supported in the punch assembly 11 in the manner explained above, is subject to downward actuating thrust by the upper ring member 47 during the closing movement of the punch unit 11.

During opening movement of the punch unit 11, the lower end portion of the punch member 12 is retracted from the die recess 16 and usually the formed workpiece 15 adheres to the punch member and is thereby lifted out of the die recess. During such opening movement the stripper means 37 initially moves upward with the punch member 12 and workpiece 15 but, at a desired point in the opening movement, the stripper pins 42 and 43 are actuated in a downward direction in the

passages

44 and 45 to thereby impart a downward stripping movement to the member 41 along the punch by which the workpiece is stripped from the latter. The downward actuating movement of the stripper pins 42 and 43 can be suitably imparted thereto as by knock-out rods 51 and 52 (see FIG. 1) extending through the carrier 18 and which are actuated downwardly in a conventional manner during upward opening movement of the punch assembly 11.

The

passages

44 and 45 through which the stripper pins 42 and 43 extend are here shown as being passages in the clamping means and are of a transverse dimension to afford suitable clearance for free movement of the stripper pins therein when the clamping means is contracted into clamping engagement with the punch member 12. The notched formation of the stripper pins 42 and 43 adjacent the lower ends thereof for receiving the enlargement means 47 provides the advantage that the stripper pins are relatively weaker at the location of the

notches

42 and 43 and, in the event that proper closing of the punch unit 11 is obstructed by engagement of the stripper means with a foreign body lying on the top of the stake assembly 13, the resulting breakage which may occur will be only a breakage of one or both of the stripper pins at such weakened portions thereof rather than a breakage of some more vital part of the apparatus. Since the stripper pins 42 and 43 are of a relatively inexpensive construction and can be readily replaced, any breakage damage thus occurring to the apparatus will be kept to a minimum value.

As shown in FIGS. 1, 2 and 4 the transverse dimension of the punch 12 in relation to the transverse dimension of the passage of the sleeve 41 is such that the punch has a relatively close fit in such passage. The sleeve therefore also serves as a guiding and steadying means for the punch for aligning the same with the die member 14. Additionally, the sleeve 41 minimizes lateral deflection or bowing of the punch and thus reduces the likelihood of punch breakage.

When breakage of the punch 14 does occur, however, it usually takes place while the punch is engaged with the workpiece 15, as shown in FIGS. 1 and 4, and the location of the break is usually at the point where the punch emerges from the assembly 11, that is in the transverse plane at the lower end of the clamping means 25. During the next upward movement of the carrier 18 the sleeve 41 lifts the broken portion of the punch, because of the relatively tight fit of the latter in the passage of the sleeve, and the workpiece 15 adhering to the broken punch is lifted out of the die 14 at the same time.

The continued upward movement of the carrier 18 results in a relative downward movement of the sleeve 41 by the actuating pins 42 and 43 but, instead of the workpiece being stripped from the punch, the sleeve carries both the broken punch and the adhering workpiece downward. This downward movement of the sleeve, broken punch and workpiece locates at least some portion or portions of these members in the path of movement of an associated feed mechanism (not shown), such as a feed mechanism of the kind shown in United States Patent No. 3,030,834 for a dislodging engagement by the feed mechanism.

The

notches

42 and 43 of the

pins

42 and 43 provide a ledge means and laterally-open guideway extending in a direction transverse to axis of the punch 12, as shown in FIG. 4. The enlargement means 47 is normally retained in the guideway formed by the notches 42b and 43 by the presence of the punch 12 in the passage of the sleeve 41 but the enlargement means will be movable out of the guideway by the dislodging action of the feed mechanism Whenever breakage of the punch 12 occurs. When the enlargement means 47 is dislodged from the

notches

42 and 43 in this manner the sleeve 41 together with the broken portion of the punch and the workpiece 15 are all ejected from the work area and will therefore not cause damage to the apparatus.

When the punch unit 11 is of the construction described above and comprises the components already referred to, namely the punch member 12, the holder member 23, the clamping means 25, the wedge means 30 and the stripper means 37, it will be seen that the punch assembly can be built up as a preformed unit having the holder member 23 as the outer housing thereof. The punch assembly 11, as such a preformed unit, can then be mounted on the carrier 18 by a relatively simple procedure and by the use of relatively simple clamping means comprising a pair of clamping lugs 54 and 55 attached to the carrier 18 by means of

studs

56 and 57 and clamping

nuts

58 and 59 applied to the latter. The

lugs

54 and 55 have suitably shaped inner end portions which cooperate with the holder member 23 by engaging .in a groove 60 provided in the side wall portion 26 thereof.

As was mentioned above the punch member 12 is disposed in the holder member 23 so as to be located on the common axis 33 of the latter. It is important that the placing of the punch assembly 11 on the carrier 18 likewise locates the punch member 12 in a proper axial relation to the die recess .16. For this purpose the carrier 18 is provided with a recess 62 in the underside thereof and a beveled annular seat 63 extending .around such recess. The recess 62 is of a size to receive the upper end portion of the holder member 23- when the punch assembly 11 is placed on the carrier 18 in a position to be engaged by the clamping lugs 54 and 55.

The holder member 2 3 has a similar annular bevel 64 thereon and is accurately positioned with the common axis 33 in a coincident relation to the axis of the die recess 16 when the latter annular bevel seatingly co-operates with the annular bevel 6 3 of the carrier 18. Proper orientation of the punch assembly 11 around the common axis 33 is achieved when the punch assembly is placed on the carrier 18, as by co-operatin g groove and

ridge elements

66 and 67 provided respectively on the holder member 23 and the carrier as shown in FIG. 2. The self-centering action of the co-operating annular bevels 63 and 64 and the orienting function of the locating

elements

66 and 67 greatly facilitate the mounting of the punch assembly 11 on the carrier 18 because the time-consuming aligning and checking operations heretofore needed are eliminated.

The stake assembly 13 is shown in FIGS. 1 and 3 and will be described next. The stake assembly 13 comprises a support ring 69 in which the die member 14 is mounted as by the use of suitable adapter rings 70) and 71. The stake assembly 13 also comprises a punch stem member 72 having upper and lower end thrust

portions

72 and 72 and which is disposed with the upper end portion 72 extending into the die member 14 and forming the bottom wall of the die recess 16. The die support ring 69 is suitably secured on the bolster plate 19 as by means of clamping

lugs

75 and 76 engaged with the support ring at a plurality of points therearound and connected with the bolster plate by screws or the like 77 and 78 extending through such lugs.

The punch stem member '72 comprises a straight piece of predetermined length of tool steel bar stock and has a transverse cross-section which is of a uniform size and uniform shape for the full length of this member between the end portions 72 and 72' thereof and which uniformshape and uniform-size cross-section is the same as the bar stock from which the piece of predetermined length was cut. The punch stem member 72 is here shown as being of a cylindrical transverse cross-section and the tool steel bar stock from which this punch stem member is cut is likewise of such a cylindrical cross-sectional shape. The upper end thrust portions 72 is, in this case, provided with a die formation 79 comprising a flat-sided axial tongue element which has been ground or otherwise formed on such end portion and projects into the die recess 16 for forming a transverse slot in the lower end of the workpiece 15 during the die shaping of the latter.

The stake assembly 13 also includes mounting means 80 at the lower end thereof for supporting and holding the die stem member 72 in the desired position relative to the die member 1 4. The mounting means 80 is located in the passage 81 of a sleeve 82 extending through the bolster plate '19 and is here shown as comprising a holder plate 83 having a central passage 84 for receiving the lower end portion 72 of the punch stem 72. The mounting means 80 also includes a hardened abutment plate 85 interposed between the holder plate 33 and the machine bed portion 21 and against which the lower end surface of the punch stem member seats.

The holder plate 83 and the abutment plate 85 are connected with the machine portion 21 as by means of securing screws 86. The end portion 72 of the punch stern member 72 is retained in the holder plate 83 by a retainer cover 87 connected with the holder plate by attaching screws 88. The retainer cover 87 co-operates with a snap ring 89 provided on the lower end portion 72 and engaged in an annular groove thereof.

In addition to the advantage that the punch stem member 72 is formed by a straight piece of predetermined length cut from tool steel bar stock, this member can be reconditioned for increased useful life by suitable grinding of the end thrust portion 72 thereof whenever such reconditioning is needed. To compensate for shortening of the punch stem member 72 which may result from such reconditioning thereof, the stake assembly 13 is provide-d with spacer means in the form of an insert member 90 of predetermined thickness interposed between the abutment plate 8 and the machine portion 21.

The insert member 90 has an axial thickness of a value to compensate for the shortening of the punch stem member 72 which has occurred by the reconditioning of the end portion 72 of the latter. The useful life of the punch stem member 72 can thus be greatly extended by repeated reconditioning of the end thrust portion 72 thereof and the substitution of progressively thicker insert members 90 in the assembly 13 to compensate for the successive shortenings of the punch stem member. When an entirely new punch stem member 7 2 is placed in the assembly 13, the insert member 90 is omit-ted.

From the construction of the stake assembly 13 as described above it will now be recognized that the punch stern member 7 2 provides substantially the same advantages in the die apparatus as the punch member 12 with the exception that the punch stem member 72 is, in this case, not reversible end-for-end because the upper end portion 7 2 has the tongue element 79 as a die formation thereon and the lower end portion 72 has the groove therein for the snap ring 89.

FIGS. 7 to 11 inclusive of the drawings show modified die apparatus 92 which is generally similar to the apparatus 10 described above but in which punch and punch

stem members

93 and 94 of the punch and stake assemblies 11 and 13 are of a non-circular transverse crosssection, in this case, a polygonal cross-section, namely a rectangular cross-section. The punch and punch

stern members

93 and 94 are both made from tool steel bar stock, and each comprises a straight piece of predetermined length cut from such bar stock and having a uniform-size and uniform-shape transverse cross-section substantially the same as the bar stock from which the pieces were cut.

The punch assembly 11 comprises components similar to those of the punch assembly 11 described above and the same reference characters, or the same reference characters with letter exponents, have been applied to various ones of such corresponding components. The contractible clamping means 25 of the punch assembly 11 differs from the clamping means 25 described above in that it comprises two

complemental segments

95 and 96 which define therebetween a passage 97 of a suitable cross-sectional size and shape to receive the punch member 93. The

segments

95 and 96 are closable into gripping engagement with the punch member 93 from opposite sides thereof by the wedging action produced on the segments by the Wedge means 30*.

In the modified punch assembly 11 the upper end portion 93 of the punch member has a flat end surface but the portion 93 at the lower end is provided with a die formation suitable for shaping a workpiece 100 located in the recess 101 of the die member 102. As shown in FIGS. 7 and 10, the die formation in this case comprises a transverse central axial rib projection 104 and transverse grooves 105 parallel to the rib projection and located on opposite sides thereof.

Since the punch stem member 94 of the stake assembly 13 is of a rectangular cross section, the die member 102 is provided with a passage 106 of a corresponding rectangular cross-section into which the upper end portion 94 of the punch stem member extends. In this case the upper end portion of the die stem member 94 has a flat end surface 107 thereon instead of a die formation and such fiat surface forms the bottom wall of the die recess 101.

The stake assembly 13 is generally similar to the assembly 13 described above and the same reference characters, or the same reference characters with letter exponents, have been applied to various ones of the parts which are the same or substantially the same in both assemblies. The lower end portion 94 of the punch stem member 94 is mounted and held in support means in a manner similar to that described above for the lower end portion 72 of the punch stem member '72 of FIG. 1, but since the punch stem member 94 is of a quadrangular transverse cross-section, it is provided with lateral lug projections 108 on opposite sides thereof in stead of a snap ring.

The lug projections 108 can be formed on the punch stem member 74 by welding or brazing lug elements on opposite sides of the piece of tool steel bar stock from which this punch stem member is formed. The lug projections 108 are received in notches 109 of the holder plate 83 and are retained therein by the retainer cover 8 7.

In the modified die apparatus 92 the inserts 38 and of the punch and stake assemblies 11* and 11 serve the same purpose and achieve the same advantages as have been explained above for the inserts 38 and 90 of the die apparatus 10. In the operation of the modified die apparatus 92 the workpiece adheres to the punch member 93 during the opening movement of the latter and is thereby lifted out of the die recess 101. The workpiece 100 can be dislodged from the punch member 93 by any conventional means suitable for this purpose.

From the accompanying drawings and the foregoing detailed description it will now be readily understood that this invention provides novel die apparatus which can be economically equipped with punch and punch stern members and that these members can be maintained in a serviceable condition throughout a prolonged operating life by reason of the fact that such punch and punch stem members are straight pieces of predetermined length of tool steel bar stock and retain the uniform-shape and uniform-size transverse cross-section of the bar stock. It will now also be understood that this invention provides novel die apparatus in which a punch assembly comprises a preformed unit, mountable and dismountable as such, on a movable carrier and which unit will automatically locate the punch in a properly aligned relation to its associated die member. Moreover, it will be understood that this invention provides novel die apparatus having a holder means for tightly gripping the punch member around its outer periphery and along a substantial portion of its length and wherein the gripping forces therebetween are evenly or substantially evenly distributed along and around the portion of the punch being gripped. Additionally, it will be understood that this invention provides novel stripper means on a punch assembly which has advantages over stripping devices heretofore provided.

Although the die apparatus of this invention has been illustrated and described herein to a somewhat detailed extent, it will be understood, of course, that this invention is not to be regarded as being limited correspondingly in scope but includes all changes and modifications coming within the terms of the claims thereof.

Having described my invention, I claim:

1. In a die apparatus; a stationary assembly comprising a support and a die thereon having an opening adapted to receive a workpiece; a carrier movable toward and away from said stationary assembly; a holder member on said carrier and having an open end and a recess extending thereinto from said open end; one portion of said holder member extending around said recess as a side wall and another portion extending transversely of said recess as an inner end wall; a punch having one end portion extending into said recess and the other end portion projecting from said holder member for co-operation with said die in performing work on said workpiece; contractible clamping means in said recess and having gripping engagement with said one end portion along the sides thereof; a wedge ring in said recess between said side wall and said clamping means; securing means effective on said wedge ring for moving the same to, and securing the same in, an axially inwardly shifted position in said recess; the adjacent sides of said wedge ring and clamping means having annular tapers both extending in a diverging relation into said recess away from said open end and disposed in mutually co-operative engagement for causing contraction of said clamping means into said gripping engagement in response to the inward axial movement of said wedge ring and for retaining the clamping means in said recess; said punch being a single straight piece of tool steel bar stock of predetermined length and having a uniform-size and uniform-shape transverse cross-section for the full length of the punch; said end portions being substantially the same whereby said punch is reversible for co-operation of either end portion thereof with said die; and back-up insert means in said holder member adjacent said inner end wall and engaged by said one end portion; said punch being subject to reconditioning by grinding of said end portions, and said insert means having an axial dimension to compensate for shortening of said punch due to said grinding.

2. In die apparatus; a stationary assembly comprising a support and a die thereon having an opening adapted to receive a workpiece; a carrier movable toward and away from said stationary assembly; a holder member on said carrier and having an open end and a recess extending thereinto from said open end; one portion of said holder member extending around said recess as a side wall and another portion extending transversely of said recess as an inner end wall; a punch having one end portion extending into said recess and the other end portion projecting from said holder member for co-operation with said die in performing work on said workpiece; contractible clamping means in said recess and having gripping engagement with said one end portion along the sides thereof; a wedge ring in said recess between said side wall and said clamping means; securing means effective on said wedge ring for moving the same to, and securing the same in, an axially inwardly shifted position in said recess; the adjacent sides of said wedge ring and clamping means having annular tapers both extending in a diverging relation into said recess away from said open end and disposed in mutually co-operative engagement for causing contraction of said clamping means into said gripping engagement in response to the inward axial movement of said wedge ring and for retaining the clamp ing means in said recess; said punch being a single straight piece of tool steel bar stock of predetermined lesgth and having a uniform-size and uniform-shape transverse cross-section for the full length of the punch;

said end portions being substantially the same whereby said punch is reversible for co-operation of either end portion thereof with said die; back-up insert means in said holder member adjacent said inner end wall and engaged by said one end portion; said punch being subject to reconditioning by grinding of said end portions, and said insert means having an axial dimension to compensate for shortening of said punch due to said grinding; a stripper member disposed around said other end portion; and axially movable thrust pins disposed on opposite sides of said punch and connected with said stripper member for actuating the latter; said clamping means having openings in which said pins are disposed and are movable with clearance to prevent binding thereof by the contraction of said clamping means.

3. Die apparatus according to claim 1 wherein said stationary assembly includes a die stem having a workengaging end portion extending into said die and forming at least a portion of the bottom wall of the opening thereof; said die stem being a single straight piece of tool steel bar stock of predetermined length and being subject to reconditioning by grinding of said work-engaging end portion; and holder means for said die stem including back-up means engaged by the other end portion thereof; the last-mentioned back-up means having a thickness dimension to compensate for shortening of said die stem by the grinding of said work-engaging end portion.

4. In die apparatus; a stationary assembly comprising a support and a die thereon having an opening adapted to receive a workpiece; a carrier movable toward and away from said stationary assembly; a holder member on said carrier and having an open end and a recess extending thereinto from said open end; one portion of said holder member extending around said recess as a side wall and another portion extending transversely of said recess as an inner end wall; a punch having one end portion extending into said recess and the other end portion projecting from said holder member for co-operation with said die in performing work on said workpiece; contractible clamping means in said recess and having gripping engagement with said one end portion along the sides thereof; a wedge ring in said recess between said side wall and said clamping means; (the adjacent sides of said wedge ring and clamping means having annular tapers both extending in a diverging relation into said recess away from said open end and disposed in mutually co-operative engagement for causing contraction of said clamping means into said gripping engagement in response to solely an inward axial movement of said wedge ring and for retaining the clamping means in said recess; and securing screws mounted on said holder member and effective on said wedge ring at points spaced annularly of the latter for securing said wedge ring in its axially inwardly shifted position in said recess.

5. In die apparatus having a work area; a holder means; a punch member mounted in said holder means and having a work-engageable portion projecting therefrom into said work area; work stripper means comprising sleeve means axially shiftable along said punch member portion and having a passage through which the punch member pontion extends in close fitting relation to the wall of said sleeve means; and stripper actuating pin means axially shiftable in said holder means and having projecting portions adjacent said punch member portion and carrying guide ledge means; said sleeve means having support portions engaged with said guide ledge means for connecting the sleeve means with said pins; said support portions being disengageable from said guide ledge portions, upon breakage of said punch member, by dislodging movement of said sleeve means in a direction transverse to the punch axis for removal of said sleeve means and the broken punch member portion from the work area.

6. Die apparatus according to claim 5 wherein the projecting portions of said pin means are transversely notched so as to be of decreased thickness and strength adjacent said guide ledge means; said projecting pin portions being subject to breakage at the location of the notches to facilitate the dislodgin-g movement of said sleeve means and broken punch member portion.

7. In die apparatus having a work area; a holder means; a punch member mounted in said holder means and having a work-engageable portion projecting there from into said work area; work stripper means comprising sleeve means axially shiftable along said punch member portion and having a passage through which the punch member portion extends in close fitting relation to the wall of said sleeve means; and stripper actuating pins axially shiftable in said holder means and having projecting portions on opposite sides of said punch member portion; the projecting pin portions having transverse notches in the adjacent sides thereof, and said sleeve means having support portions engaged in said notches for connecting the sleeve means with said pins; said notches providing a laterally-open guideway extending transverse to the punch member axis and said support portions being retained in said guideway by the presence of said punch member portion in said passage; said support portions being disengageable from said guideway, upon breakage of said punch member, for removal of said sleeve means from the work area with the broken punch member pontion therein.

8. In die apparatus for performing a cold Working operation on a workpiece; a sationary assembly comprising a support and a die thereon having an opening adapted to receive said workpiece; a carrier movable toward and away from said stationary assembly; a holder member on said carrier and having an ope-n end and a recess extending thereinto from said open end; one portion of said holder member extending around said recess as a side wall and another portion extending transversely of said recess as an inner end wall; a cold working punch having a portion of its length disposed in said recess and the remaining portion thereof projecting from said holder member for co-operation with said die in performing a cold working operation on said workpiece; contractible clam-ping means in said recess and having gripping engagement with said punch around its outer periphery thereof and along a substantial portion of its length; wedge means in said recess between said side wall and said clamping means; the adjacent sides of said wedge means and clamping means having annular tapers both extending in a diverging relation into said recess away from said open end and disposed in mutually co-operative engagement for causing contraction of said clamping means into said gripping engagement in response to solely an inward axial movement of said wedge means and for retaining the clamping means in said recess; and securing means on said holder member and effective on said wedge means for securing said wedge means in its axially inwardly shifted position in said recess.

9. In die apparatus according to claim 8 and including work stripper means comprising a stripper member axially shiftable along said remaining projecting portion of said punch and having a passage through which said remaining portion extends in close fitting relationship to the Wall of said stripper member; and stripper actuating pins axially shiftable in said holder means and operatively engaged with said stripper member for actuating the latter.

10. In die apparatus according to claim 9 wherein said stripper member includes support portions slidatbly engaged with a guide ledge means.

11. In die apparatus for performing a cold extrusion operation on a workpiece; a stationary assembly comprising a support and a die thereon having an opening adapted to receive said workpiece; a carrier movable toward and away from said stationary assembly; a holder member on said carrier and having an open end and a recess extending thereinto from said open end; one portion of said holder member extending around said recess as a side wall and another portion extending transversely of said recess as an inner end wall; a punch having one end portion extending into said recess and the other end portion projecting from said holder member for co-operation with said die in performing a cold extrusion operation on said workpiece; contractible clamping means in said recess and having gripping engagement with said one end portion of said punch around its outer periphery; wedge means in said recess between said side Wall and said clamping means; the adjacent sides of said wedge means and clamping means having annular locking tapers both extending in a diverging relation into said recess away from said open end and disposed in mutually co-operative engagement for causing contraction of said clamping means into said gripping engagement in response to solely an inward axial movement of said wedge means and for retaining the clamping means in said recess; and securing means on said holder member and effective on said wedge means for securing said wedge means in its axially inwardly shifted position in said recess.

12. In die apparatus, as defined in claim 11, wherein said holder member is socket shaped and wherein said punch, said holder member for the punch, said clamping means and said wedge means comprise a preassembled unit, and securing means detachably connecting said unit with said carrier.

13. In die apparatus for performing a cold extrusion operation on a workpiece; a stationary assembly comprising a support and a die thereon having an opening adapted to receive said workpiece; a carrier movable toward and away from said stationary assembly; a holder member on said carrier and having an open end and a recess extending thereinto from said open end; one portion of said holder member extending around said recess as a side wall and another portion extending transversely of said recess as an inner end wall; a cold extrusion punch having a portion of its length disposed in said recess and the remaining portion thereof projecting from said holder member for co-operation With said die in performing a cold extrusion operation on said workpiece; contract-ible clamping means in said recess and having gripping engagement with said punch around its outer periphery thereof and along a gripping portion constituting at least about fifty percent of its length; wedge means in said recess between said side wall and said clamping means; the adjacent sides of said wedge means and clamping means having annular tapers extending in a diverging rela tion into said recesses away from said open end and disposed in mutually co-operative engagement for causing a substantially equal closing movement of said clamping means along its axial length to apply a substantially equal gripping force on said punch along said fifty percent portion of its length in response to solely an inward axial movement of said wedge means and for retaining the clamping means in said recess; and securing means on said holder member and effective on said wedge means for securing said wedge means in its axially inwardly shifted position in said recess.

14. In die apparatus as defined in claim 11 wherein said holder member for the punch, said clamping means and said wedge means are removable as a unit from said carrier and are preassembled and attachable as unit to said carrier, said apparatus including securing means for detachably connecting said unit with said carrier, and means for locating said unit on said carrier.

15. In a die apparatus as defined in claim 14 wherein said clamp-ing means has axially extending passageways therethrough, and stripper means for stripping a Workpiece from said punch and movably received in said passageways for cooperation with knock out rods slidable in said carrier.

16. In die apparatus for performing a cold working operation on a workpiece comprising a carrier for carrying a tool member, a holder member on said carrier having an open side and a recess extending thereinto from said open side, said recess having a side Wall and a bottom wall, contractible clamping means in said recess having an axial opening extending therethrough from the open side of said holder member, a cold working punch having a substantial portion of its length disposed in said opening and the remaining portion projecting outwardly from said holder member and terminating in an end for engaging a workpiece, said punch having a uniform cross section for substantially the entire length thereof inwardly of its end for engaging the workpiece, said contractible clamping means having gripping engagement with said punch around its outer periphery thereof for substantially the entire periphery thereof received in said recess, a removable insert member disposed between the inner end of said punch and the bottom of said recess, wedge means in said recess between said side wall and said clamping means for causing contraction of said clamping means into gripping engagement with said punch, and securing means for securing said holder member to said carrier.

17. A die apparatus as defined in claim 16 wherein said contractible clamping means grips said punch for at least about 50 percent of its length.

18. A punch unit removable and attachable to a support therefor in a press comprising a holder member having a recess opening thereinto from one side thereof, said recess having a side wall and a bottom wall, contractible clamping means disposed in said opening and having an axial passageway therethrough extending inwardly from said one side, a punch member having a uniform cross section disposed in said passageway, said passageway corresponding in cross section to said punch member, said punch member extending outwardly from said contractible clamping means and terminating in a working end engageable with the workpiece, the cross section of said punch member being substantially uniform throughout its length, clamping means in said recess between said side wall and said contractible clamping means for effecting a contraction of said contractible clamping means to grip substantially the entire surface area of the portion of said punch received in said passageway in response to an inward axial movement of said clamping means, securing means on said holder member and extending through said clamping means and effective thereon for moving said clamping means axially inward toward said bottom wall and for retaining said clamping means in its axially inwardly shifted position to which it is moved, and, a removable insert disposed between the end of said punch and the bottom of said recess.

19. In die apparatus as defined in claim 16 wherein said wedge means slidably engages said side wall of said recess of said holder member along substantially its entire axial extent for axial sliding movement relative thereto, and wherein adjacent sides of said wedge means and said contractible clamping means have annular tapers both extending in a diverging relation into said recess away from said open side and disposed in mutually co-operative engagement for causing contraction of said clamping means into said gripping engagement with said punch member in response to solely an inward axial movement of said wedge means and for retaining the contractible clamping means in said recess.

20. A punch unit removable and attachable to a support therefor comprising a holder means including a holder member having a recess opening thereinto from one side thereof, said recess having a side wall and a bottom wall, contractible clamping means disposed in said opening and having an axial passageway therethrough extending inwardly from said one side, a punch member having a uniform cross section disposed in said passageway, said passageway corresponding in cross section to said punch member, said punch member extending outwardly of said contractible clamping means and terminating in a working end engageable with a workpiece, the cross section of said punch being substantially uniform throughout its length, clamping means in said recess between said side wall and said contractible clamping means for effecting a contraction of said contractible clamping means to grip substantially the entire surface area of the portion of the punch received in said passageway, a removable insert disposed between the end of said punch and the bottom wall of said recess, said contractible clamping means having a plurality of passageways therethrough, and a plurality of stripper pins slidably mounted in said passageways and extending through aligned passages in the bottom wall of said holder member.

21. In die apparatus, as defined in claim 19, including a sleeve supported by said holder member for axial shifting movement relative to said punch, said sleeve extending along the outwardly projecting portion of said punch and having a passage therethrough through which the outwardly projecting portion of the punch extends in a close fitting relationship.

22. In die apparatus, as defined in claim 16, wherein said holder member for the punch, said clamping means and said wedge means are removable as a unit from said carrier and are preassembled and attachable as a unit to said carrier, and wherein said carrier and said holder member have cooperably engageable means thereon for locating and positioning said unit in a predetermined position on said carrier, and securing means for detachably connecting said unit to said carrier.

23. In die apparatus, as defined in claim 22, wherein said cooperable means for locating and positioning said unit on said carrier comprises mating beveled surfaces on said carrier and said holder member, and wherein said carrier and said holder member have second cooperably engageable means thereon for locating and orienting the punch unit around the common axis defined by the cooperating beveled surfaces.

24. A punch unit removable and attachable to a support therefor in a press comprising a holder means including a holder member having a recess opening thereinto from one end thereof, said recess having a side wall and a bottom wall, contractible clamping means disposed in said opening and having an axial passageway therethrough extending inwardly from said one end, a punch member having a uniform cross section for substantially its entire length disposed in said passageway, said passageway corresponding in cross section to said punch member, said punch member extending outwardly from said contractible contracting means and terminating in a working end engageable with a workpiece, clamping means in said recess between said side wall and said contractible clamping means for effecting a contraction of said contractible clamping means to grip substantially the entire surface area of that portion of the punch received in said passageway, a removable insert disposed between the end of said punch and the bottom wall of said recess, and a sleeve supported by said holder means for axial shifting movement relative to said punch, said sleeve extending along the outwardly projecting portion of said punch and having a passage therethrough through which the outwardly projecting portion of the punch extends in a close fitting relationship.

25. A punch unit, as defined in claim 24, and wherein said punch member is adapted to cooperate with a die cavity in the press to perform a cold working operation on a workpiece, and wherein said sleeve has an end portion which is adapted to be received within the die cavity.

26. A punch and work stripper unit removable and attachable to a support therefor in a press comprising a holder means including a holder member having a recess opening thereinto from one end thereof, said recess having a side wall and a bottom wall, contractible clamping means disposed in said opening and having an axial passageway therethrough extending inwardly from said one end, a punch member disposed in said passageway and having a uniform cross section for a substantial portion of its length, said passageway corresponding in cross section to said punch member, said punch member having a portion extending outwardly from said contractible clamping means and terminating in a working end engageable with a workpiece, clamping means disposed in said recess between said side wall and said contractible clamping means for efiecting a contraction of said contractible clamping means to grip that portion of the punch received in said passageway, and a work stripper means supported by said holder means for stripping a 10 workpiece from said punch, said stripper means comprising an axially shiftable stripper member extending along the outwardly projecting portion of said punch and having a passage through which the outwardly projecting portion extends in close fitting relationship to the wall of 15 work engaging end for performing a forming operation on the workpiece and an inner end which is in abutting engagement with said contractible clamping means when its outer end engages a workpiece.

References Cited by the Examiner UNITED STATES PATENTS 884,577 4/ 1908 Giesler 10-24 987,282 3/1911 Briede 10-24 1,286,089 11/1918 Pfanstiehl 1816.5 2,047,322 7/1936 Hazelton 83461 2,227,810 1/1941 Mitchell 10-24 2,322,422 6/ 1943 Danneman 28720 2,683,042 7/1954 Bender 27950 2,832,468 4/1958 Krause 72-253 FOREIGN PATENTS 622,741 12/ 1935 Germany. 681,601 9/1939 Germany.

CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

Claims

1. IN A DIE APPARATUS; A STATIONARY ASSEMBLY COMPRISING A SUPPORT AND A DIE THEREON HAVING AN OPENING ADATPED TO RECEIVE A WORKPIECE; A CARRIER MOVABLE TOWARD AND AWAY FROM SAID STATIONARY ASSEMBLY; A HOLDER MEMBER ON SAID CARRIER AND HAVING AN OPEN END AND A RECESS EXTENDING THEREINTO FROM SAID OPEN END; ONE PORTION OF SAID HOLDER MEMBER EXTENDING AROUND SAID RECESS AS A SIDE WALL AND ANOTHER PORTION EXTENDING TRANSVERSELY OF SAID RECESS AS AN INNER END WALL; A PUNCH HAVING ONE END PORTION EXTENDING INTO SAID RECESS AND THE OTHER END PORTION PROJECTING FROM SAID HOLDER MEMBER FOR CO-OPERATION WITH SAID DIE IN PERFORMING WORK ON SAID WORKPIECE; CONTRACTIBLE CLAMPING MEANS IN SAID ONE END PORTION ALONG THE SIDES THEREOF; MENT WITH SAID ONE END PORTION ALONG THE SIDES THEREOF; A WEDGE RING IN SAID RECESS BETWEEN SAID SIDE WALL AND SAID CLAMPING MEANS; SECURING MEANS EFFECTIVE ON SAID WEDGE RING FOR MOVING THE SAME TO, AND SECURING THE SAME IN, AN AXIALLY INWARDLY SHIFTED POSITION IN SAID RECESS; THE ADJACENT SIDES OF SAID WEDGE RING AND CLAMPING MEANS HAVING ANNULAR TAPERS BOTH EXTENDING IN A DIVERGING RELATION INTO SAID RECESS AWAY FROM SAID OPEN END AND DISPOSED IN MUTUALLY CO-OPERATIVE ENGAGEMENT FOR CAUSING CONTRACTION OF SAID CLAMPING MEANS INTO SAID GRIPPING ENGAGEMENT IN RESPONSE TO THE INWARD AXIAL MOVEMENT OF SAID WEDGE RING AND FOR RETAINING THE CLAMPING MEANS IN SAID RECESS; SAID PUNCH BEING A SINGLE STRAIGHT PIECE OF TOOL STEEL BAR STOCK OF PREDETERMINED LENGTH AND HAVING A UNIFORM-SIZE AND UNIFORM-SHAPE TRANSVERSE CROSS-SECTION FOR THE FULL LENGTH OF THE PUNCH; SAID END PORTIONS BEING SUBSTANTIALLY THE SAME WHEREBY SAID PUNCH IS REVERSIBLE FOR CO-OPERATION OF EITHER END PORTION THEREOF WITH SAID DIE; AND BACK-UP INSERT MEANS IN SAID HOLDER MEMBER ADJACENT SAID INNER END WALL AND ENGAGED BY SAID ONE END PORTION; SAID PUNCH BEING SUBJECT TO RECONDITIONING BY GRINDING OF SAID END PORTIONS, AND SAID INSERT MEANS HAVING AN AXIAL DIMENSION TO COMPENSATE FOR SHORTENING OF SAID PUNCH DUE TO SAID GRINDING.