US3254550A

US3254550A - Die apparatus

Info

Publication number: US3254550A
Application number: US384065A
Authority: US
Inventors: John N Mcdonald
Original assignee: Mcdonald Tool & Die Co Inc
Current assignee: Mcdonald Tool & Die Co Inc
Priority date: 1964-07-21
Filing date: 1964-07-21
Publication date: 1966-06-07
Anticipated expiration: 1983-06-07

Description

June 7, 1966 MCDONALD 3,254,550

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United States Patent 3,254,550 DIE APPARATUS John N. McDonald, McDonaldTool & Die Co., Inc., 2125 E. Rich, Spokane, Wash. Filed July 21, 1964, Ser. No. 384,065 Claims. (Cl. 83128) This invention relates to a concentric die apparatus for stamping out sheet materials.

The present invention is concerned with a concentric or coaxial die apparatus for use in a conventional die press, and is principally concerned with a die apparatus having long life, fast action and easily replaceable die and punch components. The present invention utilizes a die completely housed within a single rigid member, all of the moving components of the apparatus being coaxially guided so as to insure correct alignment of the components.

It is a first object of this invention to provide such an apparatus wherein all of the moving parts being guided concentrically so that no part of the die apparatus can become bent or misaligned during use thereof.

Another object of this invention is to provide such a die apparatus with a rigid supporting housing that surrounds the die and insures correct alignment of the moving components. This is in contrast with the normal die that is supported by posts offset from the moving die and punch elements.

Another object of this invention is to provide such an apparatus capable of high speed Work on thin strip metal, the die apparatus being designed for high volume punch operations.

Another object of this invention is to provide such a die apparatus wherein the basic components are to be considered as permanent, the various dies and punches being interchangeable on the apparatus when desired.

These and further objects will be evident from a study ofthe following disclosure, taken together with the accompanying drawings which form a part of that disclosure. It is to be understood that this peculiar form of the invention is not intended to be the limit of its scope, the invention itself being defined in the claims that follow the specification.

In the drawings:

FIGURE 1 is a perspective view of the die as it would be used on. a press, a strip of the metal being utilized in the process being shown;

FIGURE 2 is'a front view of the die as seen from the left in FIGURE 1;

FIGURE 3 is a side view of the die as seen from the right in FIGURE 2;

FIGURE 4 is an enlarged bottom view of the die as seen along line 44 in FIGURE 2;

FIGURE 5 is an enlarged verticalsection view taken along line 55 in FIGURE 3;

FIGURE 6 is a sectional view taken at a reduced scale along line 6-6 in FIGURE 5;

FIGURE 7 is a sectional view taken at a reduced scale along line 77 in FIGURE 5;

FIGURE 8 is a sectional view taken at a reduced scale along line 8-8 in FIGURE 5;

FIGURE 9 is a sectional view at a reduced scale 'taken along line 99 in FIGURE 5;

FIGURE 10 is a fragmentary sectional view taken along line 1010 in FIGURE 5;

FIGURES 11 through 15 are a series of diagrammatic views similar to FIGURE 5 illustrating the operation of the die;

' die in its upper or initial position;

FIGURE 12 is a view similar to FIGURE 11 showing ing downward movement of the plunger prior to contact of the metal strip;

FIGURE 13 is a fragmentary section of the lower portion of the die showing the cutting of the strip by the respective die and plunger combinations;

FIGURE 14 is a view similar to FIGURE 11 showing upward movement of the plunger; and

FIGURE 15 is a view showing the stripping of the metal part from the internal die aperture.

The present invention can best be understood from the disclosure in FIGURE 5, which is a sectional view taken through the entire apparatus and showing all of its basic components. The overall structure of the die apparatus can be seen in FIGURES 1 through 4 which are external views thereof. FIGURES 6 through 10 are internal sectional views to show the relation of the various components. Referring to these drawings, the die apparatus constitutes a rigid supporting member including a base- 10 extending upwardly from a plane base surface 8. Base 10 is provided with a transverse rectangular aperture 12 extending through its lower portion. The transverse aperture 12 is in open communication with a rectangular front opening 13, the purpose of which will be evident shortly.

The base 10 is shown in a rectangular configuration in the as shown in FIGURES 1 through 3, the blocks 9 being then bolted or clamped to the base of the press for support purposes.

The base 10 is also provided with a vertical aperture 14 that opens to the transverse aperture 12. The vertical aperture 14 is a cylindrical upright aperture centered about a central verticalaxis in the base 10 perpendicular to base surface 8. All of the various components to be described below are also centered coaxially about this same axis, so that all of the moving parts involved in this structure move coaxially parallel to the center longitudinal axis of base 10.

The base 10 isprovided with a circular retainer ring 16 at its upper surface, the ring 16 being secured to the base 10 by a plurality of recessed screws 17 located about the periphery of the ring 16. The ring 16 is provided with external threads that are engaged by internal threads at the lower end of a cylindrical closed retainer cap 15 that covers the top of the base 10. The retainer cap 15 is mounted coaxially about the axis described relative to the base 10. All of the moving parts of the apparatus are guided either within the base 10 or within the cap 15 so that none of the moving parts are exposed or mounted eccentrically relative to the central axis just described.

Mounted on the base 10 in a fixed location extending upwardly past the bottom surface of the transverse aperture 12'is a punch and die pad 11 having an upwardly directed punch 18. Again, the cylindrical periphery of the pad 11, as well as the periphery of the punch 18, is coaxial with the upright central axis of base 10, which is perpendicular to the base surface 8. The pad 11 is press fit within the base 10 and is removable by forcing it in a downward direction.

The punch 18 is surrounded by a stripper plate 22 having an aperture that is complementary to the punch 18 so that the plate 22 can slide relative to the punch 18 in a direction parallel to the axis of base 10. The plate 22 is limited in its upward movement by means of retaining Patented June 1966 i J) screws 23 (FIGURE 10) that threadably engage the plate 22 at their upper ends. The lower ends of the screws 23 are enlarged and slide within enlarged apertures 24. The

upward movement of the plate 22 is governed by the location of the top shoulders of the respective apertures 24, so that the plate 22 cannot move upwardly beyond the position shown in FIGURES and 10. However, the plate 22 is free to move downwardly due to the relief provided between the plate 22 and the pad 11.

There are provided a series of four biasing springs 25 recessed within apertures 26 in the base and located about the surface of the plate 22 in abutment with the lower surface thereof. The springs 25 are bottomed on recessed screws 27 threadably engaged with the aperture 26 and adjustable so as to allow adjustment of the spring pressure exerted on the plate 22. Thus, the plate 22 will normally be maintained in the position shown in FIG-

URES

5 and 10, but can yield downwardly when necessary. The purpose of the stripper plate 22 is to free the metal strip or tape from the punch 18 after the desired work configuration has been cut therefrom.

Mounted within the base 10 is a plunger 31. The plunger 31 is slidably mounted within a cylindrical collar 42 press fit within the vertical aperture 14 of the base 10. Sliding movement of the plunger 31 is facilitated by means of a ball bearing collar assembly 43 of conventional manufacture that separates the supporting cylindrical surface 44 of plunger 31 and the collar 42. The collar assembly 43 has a plurality of longitudinally spaced circumferential rows of ball bearings projecting from it in rolling contact with both the interior surface configuration of collar 42 and the complementary exterior surface configuration of plunger 31. The purpose of the ball bearing assembly 43 is to reduce frictional resistance to sliding movement and to insure proper operation of the device athigh constant speeds.

The plunger 31 is provided with a removable die 28 at its lower end secured thereto by means of two screws 30. The die 28 has a die aperture 45 that is complementary to the punch 18 and also, coaxial therewith. Located within the aperture 45 is a reciprocable stripper 37 slidably guided by the aperture 45. Stripper 37 is biased upwardly by means of a spring 38 that surrounds its outside periphery within the plunger 31. The spring 38 bears upwardly against an enlargement 40 formed at the top end of the stripper 37. The stripper 37 bears upwardly against a flat cylindrical washer 41 which is contacted at its upper surface by means of stripper push rods 32 that slidably extend along the full height of the plunger 31 within apertures cut therethrough.

There also is provided a fixed punch 36 that is press fit Within an aperture 46 formed through the center of the plunger 31. The punch 36 is also coaxial and is designed to, punch out a section of the metal strip at the center of the main portion formed by the punch 18. Punch 36 cooperates with a die aperture 20 at the center of the punch 18, which extends through the height of the pad 11 and which is relieved at 21 to permit free movement of metal received therein after initial forming at the top portion thereof. The punch 36 is fixed to the plunger 31 and the stripper 37 is free to reciprocate relative to the punch 36, as will be evident below.

The top end of the plunger has a cap 34 fixed to it and extending radially outward therefrom. The cap 34 is fixed to the plunger 31 by means of a recessed screw 35 shown in dashed lines in FIGURE 6. The cap 34- provides a radial shoulder against which the plunger spring 33 that surrounds the plunger 31 can push upwardly. The lower end of the spring 33 bears against the retainer ring 16, so that the relatively heavy spring 33 normally biases the plunger 31 to an upward position, the initial position of the apparatus being as shown in FIGURE 5.

There also is provided a hammer 47 that extends through an opening in the retainer cap and which has a lower shoulder that bears against the top of the cap 34 for transmission of force to the plunger 31 to cause downward motion thereof. The hammer 47 is provided with an axial extension 48 that fits within the aperture 46. The connection between the extension 48 and the aperture 46 might be rather loose so that the hammer 48 can be replaced when desired. The apparatus as described and shown is readily adapted to a conventional die press without modification of the press structure.

The operation of the die is rather simple and is best understood from a study of the drawings as shown in FIG URES 11 through 12. In its initial position shown in FIGURE ll, the lower surface of the stripper 37 protrudes slightly beyond the lower surfaces of the punch 36 and die 28. The amount of protrusion of the stripper 37 should be slightly more than the thickness of the metal strip to be punched. The strip itself is denoted by the numeral 50. It rests upon the stripper plate 22 and the punch 18, the upper surfaces of both being coplanar at this time.

The initial downward movement of the plunger 31 releases the stripper push rods 32, which had been in engagement with the inside surface of the retainer cap 15. This permits the spring 38 to push upwardly against the enlargement 40 and to cause the stripper 37 to recess slightly above the lower surfaces of the die 28 and punch 36, exposing the die aperture of the die 28 and the external periphery of the punch 36. The upward movement of the stripper 37 is restricted by the limited amount of free space between the washer 41 and the lower inner surface of the plunger 31 adjacent thereto.

Continued downward movement of the plunger 31 due to pressure on the hammer 48 causes the strip 50 to be punched as shown in FIGURE 13. The die 28 will press downwardly against the strip 50, causing the stripper plate 22 to move downwardly in opposition to the springs 25. The pressure exerted upwardly by the springs 25 must be adjusted by means of the screws 27 to insure that this pressure will not cause the strip 50 to spread. The downward movement of the die 28 over the punch 18 cuts the outside configuration of the material desired, while the movement of the punch 36 within the die aperture 20 cuts the inside configuration, in this instance forming a circular washer with an inner hole. The washor is shown as 51, and the material removed from the hole is shown as 52. The washer 51 is then located within the die aperture of die 28 and the material removed from the hole is located within the die aperture 20.

Upward movement of the plunger 31 is illustrated in FIGURE 14, the washer 51 remaining as described and the material removed from the hole, shown as 52, remaining within the aperture 20. The strip 50 is freed from the periphery of the punch 18 by the upward movement of the stripper plate 22, and is free to be reciprocated to its next position as shown in FIGURE 15.

In FIGURE 15, the stripper push rods 32 have again abutted the upper inside surface of the retainer cap 15 and have caused the stripper 37 to move downwardly relative to the die 28 and punch 36, thereby causing the washer 51 to be removed from the die aperture. The washer 51 is then blownfrom the die by means of an air nozzle 53 best seen in FIGURES 2, 3, and 9. The nozzle 53 extends inwardly to a location in close proximity to the plunger 31 and is located elevationally at the location wherein the washer 51 will be stripped from the die aperture of die 28. The nozzle 53 can be connected to any conventional source of compressed air. The washer 51 is blown through the opening 13, while the strip 50 moves intermittently through the transverse aperture 12 in base 10. Thus, the strip of metal 50 can be moved in an almost continuous cycle through the base 10, and the washers or other objects stamped therefrom are blown out the front opening 13, the plunger 31 being therefore capable of reciprocating along its central axis at the very rapid rate of speed.

While thedie apparatus as illustrated is designed fo mechanical operation on a conventional die press, the same apparatus could be readily converted to hydraulic or pneumatic operation by utilizing hydraulic pressure or pneumatic pressure to reciprocate the plunger 31 within the retainer cap 15. The cooperation between the various punch and die units would remain unaltered.

It is important to note that the die apertures and die members are all located coaxially within the rather heavy rigid base 10. Thus, the die 28 can be readily removed by releasing the screws 30, and another die 28 substituted in its place. Such substitution will also involve the substitution of the coaxial stripper 37. Punch 36 is also interchangeable, and can be eliminated where an internal hole in the finished object is not desired. Also, the punch and die pad 11 is mounted coaxially within the base and it also can be interchanged with other pads 11 to complement the desired die 28, the stripper plate 22 also being interchanged in such an instance. The important factor is that all of these elements are mounted coaxially within the single base 10,. so that they can be interchanged at will with other die and punch combinations, allowing the basic die apparatus to be used in the formation of many different objects. There is no danger of misalignment due to the coaxial mounting of all of the elements within the single rigid base member 10. This is to be contrasted with the normal die, which is mounted on posts offset from the die and punch, and which is not capable of a high speed operation over long periods without some portion thereof being distorted and losing alignment. The present die apparatus, when manufactured according to precision machining tolerances, is capable of use over a long period of time to fabricate thousands of identical parts with an extremely high degree of accuracy. The apparatus has been used primarily in the stamping of washers or other circular elements from rather thin strips of metals, but quite obviously the shape of the member being punched is not limited by any physical consideration relative to the apparatus. the coaxial relationship existing between the parts be maintained for insured accuracy.

Various modifications might be made in the specific structure illustrated without deviating from the scope of the invention as it was intended to be described. For this reason, only the following claims are intended to limit the scope of this invention.

'Having thus described my invention, I claim:

1. A die apparatus, comprising:

a rigid base member provided with a plane outside base surface and an interior recess terminating within said base member short of said base surface, said recess being bounded by an interior surface configuration perpendicular to said base surface;

said base member being further provided with a transverse aperture in open communication with said recess at the end of said recess proximate to said base surface;

said base member including a releasable retainer cap enclosing the remaining end of said recess remote from said 'base surface;

a plunger mounted within said base member for reciprocable motion parallel to said wall surfaces, said plunger having an exterior surface configuration complementary to said interior surface configuration of said base member and guided thereby;

said plunger having one end thereof projecting toward said retainer cap, the remaining end of said plunger being located within the transverse aperture of said base member;

a compression spring enclosed within said base member and encircling said plunger, said spring being operatively engaged between said plunger and said base. member to urge said plunger toward said retainer cap;

It is only essential that 40 and complementary coaxial die and punch members formed respectively on said remaining endv of said plunger and on said base member in coaxial opposition to one another.

5 2. A die apparatus, comprising:

said base member including a releasable retainer cap enclosing the remaining end of said recess remote from said base surface;

a plunger mounted within said base member for reciprocable motion in a direction perpendicular to said base surface, said plunger having an exterior surface configuration complementary to said interior surface configuration of said base member and guided thereby;

said plunger having one end thereof projecting toward said retainer cap, the remaining end of said plunger being located within said aperture of said base member and being provided with an axially apertured die member fixed thereto;

a punch member fixed to said base member in axial 3 alignment with the die member on said plunger, said punch member being complementary to said die member;

and first compression spring means enclosed within said base member operatively engaged between said base member and said plunger to normally urge the plunger in a direction opposite to said base surface.

3. A die apparatus as defined in claim 2 further com prising:

a stripper member movably mounted on said plunger at said remaining end thereof, the'stripper member being formed with an exterior surface configuration complementary to the interior surface configuration of the aperture of said die member and slidably engaged therewith;

second compression spring means located within said plunger and encircling said stripper member operatively engaged between said stripper member and said plunger to urge said stripper member inwardly toward said one end of said plunger;

and a rigid rod slidably received through said plunger for axial motion perpendicular to said base surface, said rod having one end thereof projecting through said one end of said plunger and the remaining end thereof in abutment with the stripper member.

4. A die apparatus as defined in claim 2 further comprising:

a stripper plate surrounding said punch, said stripper plate having an axial aperture complementary to the punch and slidably mounted thereon;

. motion limiting means fixed to said base member in the path of motion of said stripper plate to limit movement of said stripper plate relative to said base member in a direction toward said retainer cap;

and biasing means operatively connected between said base member and said stripper plate to normally ug: said stripper plate toward said retainer cap.

5. A die apparatus as defined in claim 2, wherein said interior surface configuration of said base member and said exterior surface configuration of said plunger are cylindrical in shape;

and a ball bearing collar interposed between said interior surface configuration of said base member and said exterior surface configuration of said plunger having a plurality of longitudinally spaced circumferential rows of ball bearings projecting therefrom 2,627,212 2/1953 Conner et a1. 83-621 X in rolling cdntact with the respective surface con- 2,768,560 10/1956 Hirson 83-588 X figurations. 3,143,015 8/1964 Luther et a1. 83-125 X 3,148,574 9/1964 Heigl et a1. 83-618 X References Cited by the Examiner UNITED STATES PATENTS 5 FOREIGN PATENTS 1,040,861 5/1953 France.

735,119 8/1903 Leavitt 83-125 X 1,236,338 8/1917 Miller 83-124 WILLIAM W. DYER, JR., Primary Examiner. 1428174 9/1922 Luther 83.424 I. M. MEISTER, Assistant Examiner.

2,576,295 11/1951 Good 83-125 X

Claims

1. A DIE APPARATUS, COMPRISING: A RIGID BASE MEMBER PROVIDED WITH A PLANE OUTSIDE BASE SURFACE AND AN INTERIOR RECESS TERMINATING WITHIN SAID BASE MEMBER SHORT OF SAID BASE SURFACE, SAID RECESS BEING BOUNDED BY AN INTERIOR SURFACE CONFIGURATION PERPENDICULAR TO SAID BASE SURFACE; SAID BASE MEMBER BEING FURTHER PROVIDED WITH A TRANSVERSE APERTURE IN OPEN COMMUNICATION WITH SAID RECESS AT THE END OF SAID RECESS PROXIMATE TO SAID BASE SURFACE; SAID BASE MEMBER INCLUDING A RELEASABLE RETAINER CAP ENCLOSING THE REMAINIGN END OF SAID RECESS REMOTE FROM SAID BASE SURFACE; A PLUNGER MOUNTED WITHIN SAID BASE MEMBER FOR RECIPROCABLE MOTION PARALLEL TO SAID WALL SURFACES, SAID PLUNGER HAVING AN EXTERIOR SURFACE CONFIGURATION COMPLEMENTARY TO SAID INTERIOR SURFACE CONFIGURATION OF SAID BASE MEMBER AND GUIDED THEREBY;