US3392614A

US3392614A - Ejector punch

Info

Publication number: US3392614A
Authority: US
Inventors: Richard E Feldborg
Original assignee: Richard E. Feldborg
Current assignee: RICHARD E FELDBORG
Priority date: 1965-12-20
Filing date: 1965-12-20
Publication date: 1968-07-16
Anticipated expiration: 1985-07-16

Description

R. E. FELDBORG EJECTOR PUNCH July 16, 1968 Filed Dec. 20, 1965 36 INVENTOR RICHARD E. FELDBORG United States Patent 3,392,614 EJECTOR PUNCH Richard E. Feldborg, 16174 Rosemont Ave., Detroit, Mich. 48219 Filed Dec. 20, 1965, Ser. No. 514,921 7 Claims. (Cl. 83-128) ABSTRACT OF THE DISCLOSURE A piercing punch assembly having a pin for ejecting the cut blank from the end of the punch. The assembly includes a plurality of balls carried within the punch and which when the punch is inverted and the pin retracted Will lock the pin member in the retracted position to permit the end of the punch and the pin to be reground.

. The present invention relates to piercing punch assemblies, particularly to such an assembly having means for ejecting the cut blanks or slugs which have the tendency to adhere to the punch assembly and more particularly to a new means for maintaining the ejector pin in a retracted position while the working face of the punch and the pin are being ground.

Piercing punch assemblies have been heretofore provided which include a spring actuated pin for ejecting the blank from the end of the punch as the punch is being retracted from the work material. These have also sometimes included means for maintaining the ejector pin in a retracted position with the working surface thereof coplanar with the working surface of the punch so that these surfaces can be ground at the same time and without altering the relative positions of these surfaces in the working positions.

One such assembly is disclosed in US. Patent No. 2,- 917,960 issued Dec. 22, 1959, to Robert A. Gargrave. The assembly therein disclosed comprises a headed pin member carried within an axial bore provided in the punch and being spring urged toward a position in which a portion of the pin member extends axially from the working surface of the punch. The spring is relatively light so that it will yield when the end of the pin contacts the surface of the work material. The pin remains in the retracted position until the punch is retracted from the work material and as the punch is being retracted, the force on the end of the pin is reduced sulficiently to permit the spring to move the pin to an extended position to thereby dislodge the blank from the end of the punch.

\ The assembly further includes means in the form of a cotter pin adapted to be engaged beneath the head of the ejector pin for maintaining the pin in a retracted position with the working surfaces of the punch and pin coplanar so that these surfaces can be ground and when the grinding operation is completed, the pin when again extended will assume a position in which the working surface thereof is the same distance from the working surface of the punch as it was before the grinding was undertaken.

While pierce punch assemblies like those disclosed in the aforementioned patent have been suitable for their intended purpose, they are generally quite expensive because of the mechanism required for actuating the ejector pin and also by reason of the particular mechanism utilized for maintaining the ejector pin in a retracted position for grinding. Further, a large part of the retracting mechanism extends exteriorly of the punch and this limits the number of such punches which can be provided in a given space and interferes with retraction of the ejector pins where a large number of punches are provided within relatively close proximity. Further, the cotter pins can dislodge from the punches during the grinding operation ice which may result in damage to the working surface of the pin.

The present invention overcomes these difliculties by providing a piercing punch assembly in which means disposed entirely within the punch are provided for selectively maintaining the ejector pin in a retracted position. Thus a large number of punches can be provided within a given area. Once in the retracted position there is little danger of the pin accidentally disengaging and thereby assuming the extended position during grinding. The particular retaining means as well as the ejector pin assembly can be produced much more economically than heretofore possible so that the cost of producing piercing pin assemblies is substantially reduced by the construction of the present invention.

It is an object then .of the present invention to reduce the cost of piercing punch assemblies by providing a more economically produced ejector pin mechanism for such assemblies.

It is another object of the present invention to facilitate the grinding of the work surfaces of a piercing punch and the ejector pin for such punches by providing a new means for maintaining the ejector pin in a retracted position during the grinding operation.

It is still another object of the present invention to increase the number of piercing punch assemblies .of the type having means for retaining the ejector pin in a retracted position, which can be provided in a given area by positioning such means entirely within the piercing punch.

Still further objects and advantages of the present invention will readily occur to one skilled in the art to which the invention pertains upon reference to the following description. The description makes reference to the following drawings in which like reference characters refer to like parts throughout the several views and in which:

FIG. 1 is a longitudinal cross sectional view partly diagrammatic illustrating one preferred piercing punch assembly of the present invention in use,

FIG. 2 is a fragmentary cross sectional view of a portion of the structure shown in FIG. 1 enlarged somewhat for purposes of clarity and illustrating the ejector pin in the position assumed as the working surface of the punch strikes the work material.

FIG. 3 is a fragmentary cross sectional view similar to FIG. 2 but illustrating the operation of retraction retaining mechanism of the present invention and illustrating the piercing punch assembly in an inverted position to permit the work surfaces thereof to be ground for sharpening, and

FIG. 4 is a cross sectional view similar to FIG. 2 but illustrating another preferred embodiment of the present invention.

Now referring to the drawings for a more detailed description of the present invent-ion, one preferred embodiment is illustrated in FIGS. 1-3 as comprising a punch member generally indicated at 10 carried by a holder comprising a punch shoe 12 and a punch retainer 14 secured one to the other in any convenient manner such as by screws or dowels (not shown). A die retainer 16 is spaced from and parallel to the punch retainer 14 and carries a die shoe 18 on the side opposite the punch retainer 14. A stripper member 20 is disposed intermediate and in parallel relationship with the punch retainer 14 and the die retainer 16. The die retainer 16 and the die shoe 18 carry a die button 22 in a position to axially receive the end of the punch member 10 as will become more apparent as the description proceeds. The stripper member 20 is provided with 'an opening 24 for permitting movement of the end of the punch member 10 into the die button 22. The stock or work material 26 to be cut is disposed intermediate the stripper memportion 30 so that when the punch shoe and the punch retainer 14 are. secured together, the punch member is locked in position. Such a means of retaining the punch member 10 in position is referred to as a head type or shoulder punch assembly. It will be apparent that other means for retaining the punch assembly can be 'used as well and such assembly could be a conventional ball lock type assembly rather than the assembly illustrated.

The barrel 32 of the punch member 10 extends from the bore 28 and terminates in a reduced diameter nose portion 36. The nose portion 36 is axially aligned with the'opening 24 in the stripper member and with the interior-of the die button 22. As can best be seen in FIGS. 2-3, the end of the nose 36 is formed with a planar work surface 38 which is normal to the axis of the punch member 10.

Also as can best be seen in FIGS. 2-3, the punch member 10 is provided with an axial through bore 40.

The punch member 10 is counterbored axially from the upper end to form an enlarged portion 42 of the bore 40 and then counterbored again from the upper end to form a portion 44 of a diameter intermediate the diameters of the through bore 40 and the enlarged portion 42. The juncture of the

portions

42 and 44 is formed by an upwardly inclined shoulder 46 and the juncture between the bore 40 and the portion 42 is formed by a similarly inclined shoulder 48.

An ejector pin 50 is carried in the through bore 40 and comprises an elongated member having a straight portion 52 adapted to be axially received in the bore 40 and an integrally joined spring portion 54 carried in the enlarged portion 42. A screw stud 56 (FIG. 1) received in the upper end of the enlarged portion 42 retains the ejector pin 50 in place and provides a seat for the free end of the spring portion 54.

A cup member 58 is staked or otherwise fixed to the straight portion 52 of the pin 50 and includes a frusto conical side wall 60 for receiving the spring portion 52 and a cylindrical portion 62 through which the straight portion 52 extends. The side wall 60 is substantially concentric to the shoulder 46 and the upper edge of the wall 60 extends closely adjacent the inner Wall forming the enlarged bore 42 so that the wall 60 and the shoulder 46 coact to limit the extension of the ejector pin 50. The spring portion 54 bears against the cup member 58 to urge the pin 50 toward the extended position shown in FIG. 1 and in which a portion of the pin 50 extends from the end of the nose portion 36 of the punch member 10. A plurality, preferably three, of balls 64 are loosely carried in the bore portion 44.

In operation, the punch assembly is normally in the position illustrated in FIG. 1. The stock material 26 is fed across the die retainer 16 while the separate assemblies 12-14 and 1618 reciprocate relatively to one another. During such motion, the nose portion 36 of the punch member 10 passes through the opening 24 in the stripper plate 20 and pushes through the work material 26 and into the die button 22 to cut a blank from the material 26. The blank will normally drop downwardly through the die button 22 and fall through an opening 66 provided in the die shoe 18.

The stripper member 20 will prevent the cut blank from following the punch member 10 as it is retracted but without more, the blank sometimes might adhere to the work material 26 as the punch member 10 is withdrawn. The ejector pin 50 obviates this. The spring portion 54 is relatively light so that as the working surface 38 of the punch member 10 comes intocontact with the surface of the work material 26, the ejector pin 50. will be moved to the retracted position shown in FIG. 2 so that it will produce no interference with the cutting action produced by the punch member 10. When the cut is made,-the force-is released. from the end of the ejector pin 50 and the spring .portion 54 moves the pin 50 to the extended position illustrated in. FIG, .1. This causes the end :of the pin 50 to bear fagainsttthe cut blank and to push .itdownwardly through the die button 22 and the opening 66. I .7 It is apparent that the work surface 38 of the punch member 10 must be periodically ground oif to maintain the surface planar and the edges sharp. Further, that without some means ofmaintaining the ejector pin 50 in aretracted position duringwthis operation the end of the. pin 50 would interfere with-the grinding and sharpening-Also, since. rather close tolerances must be kept betweenthe work surface 38 and the end of the pin 50 when the pin 50 is extended and also because the end surface of thepin 50 also forms a part of the work surface 38, it is, desirable to retract the pin 50 to a position in which the end surface of the pin 50 is substantially co-planar with the work surface 38 during grinding.

To grind the Work surface 38 and the end surface of the pin 50 then the punch assembly is first inverted to the position shown in FIG. 3. The pin 50 is then pushed to a position in which the end surface is below-the work surface 38 by any suitable tool (not shown). This permits the ball'members 64 to fall to a position intermediate the wall 60 of the cup member 58 and the shoulder 46. The diameter of the "balls 64 and the angle of inclination of the Wall portion 60 and the shoulder 46 is such that with the balls 64 in this positionthe pin 50 is maintained in a retracted position in which the end surface of the pin50 is substantially planar with the work surface 38.'The free edge of the wall 60 is spaced suificiently close to the wall defining the bore portion 42 to prevent the ball members 64 from falling'past the cup member 58 and the cylindrical portion 62 of the cup member 58 is spaced sufliciently close to the wall defining the boreportion 44 to -prevent the ball members 64 from working themselves pastthe cup member 58 and into the bore portion 44, before grinding.

The surface 38 and the end surface of the pin 50 then can be ground without the danger of the pin 50 accidentally moving'to the extended position. After the grinding has been accomplished, the assembly is againireturned to its operating position and the pin 50 is pushed into the punch member 10 to permit the balls 64 to fall past the cylindrical portion 62 of the cup member 48 and to return to the bore portion 44 out of the way of the operation of the pin 50. After re-grinding, the end surface of the pin member 40 and the work surface 38, these surfaces will be spaced the same distances in the extended position as they were before grinding.

FIG. 4 illustrates a punch assembly similar to the one described but in which a pin 152 is formed integrally with a cup 158 similar to the straight portion 52 and cup 58 of the assembly of FIGS. 1-3. A spring 154 is separate from the cup member 158 and pin 152 and urges the pin 152 toward the extended position but is otherwise substantially as described for the modification of FIGS. 1-3.

It is apparent that a punch assembly has been described in which retraction of the ejector pin for resurfacing has been greatly facilitated over previous means for performing this function. The particular retaining mechanism is relatively inexpensive and since it is located entirely within the punch member 10, it in no way interferes with the placement and positioning of the punch members in an assembly.

It is also apparent that although I have described but two embodiments of my invention, many changes and modifications can be made therein without departing from the spirit of the invention as expressed by the appended claims.

I claim: 1. A piercing punch member comprising,

(c) spring means carried in said bore and urging said pin member toward an extended position in which the 6 end of said pin member extends from the end of said body portion, (d)"means disposed within said bore and selectively operable to retain said pin member in a retracted (a) a body portion having a longitudinal bore, 5 position in which the end of said pin member is sub- (b) a pin member axially slidably mounted in said bore, 'stantially coplanar with the end of said body portion, (c) spring means carried in said bore and urging said (e) said last mentioned means comprising a counterpin member toward an extended position in which the bore in said body portion to form an enlarged porend of said pin member extends from the end of said tion of said bore; a second counterbore in said body body portion, 10 portion to form a second enlarged portion adjacent :(dz) 1, means disposed within said bore and selectively to and of a smaller diameter than said first enlarged operable to retain said pin member in a retracted portion; a frusto-conical shoulder formed in said position in which the end of said pin member is subbody portion at the junction of said enlarged porstantially coplanar with the end of said body portion, tions; a cup member secured to said pin member and (e) said last mentioned means comprising a frustocarried within said enlarged bore portions and havconical shoulder portion formed in said bore, a ing a. frusto-conical sidewall engaging with said frusto-conical member carried by said pin member shoulder to limit extended movement of said pin and adapted to be urged against said shoulder portion member; said cup member further having a cylinby said spring means to limit outward extension of drical portion adapted to be received in said second said pin member, and a plurality of balls carried enlarged portion;aplurality of ball members normalwithin said bore and adapted to be wedged interly positioned in said second enlarged portion and normediate said shoulder portion and said frusto-conical mally retained therein by said cylindrical portion of member to retain said pin member in said retracted said cup member; and said ball members being selecposition. tively. movable from said second enlarged portion to 2. A piercing punch member comprising, a position intermediate said sidewall of said cup mem- (a) a body portion having a longitudinal bore, ber and said shoulder to retain said pin member in a (b) a pin member axially slidably mounted in said retracted position.

bore, 5. The piercing punch as defined in claim 4 and in (0) spring means carried in said bore and urging said which said spring means comprises a spring member pin member toward an extended position in which carried in said first enlarged portion and having one end the end of said pin member extends from the end of seated in said cup member. said body portion, 6. The piercing punch as defined in claim 5 and in ((1) means disposed entirely within said bore and selecwhich said spring member is integrally formed with said tively operable to retain said pin member in a repin member. tracted position in which the end of said pin mem 7. A piercing punch member comprising, ber is substantially coplanar with the end of said (a) a body portion having a longitudinal bore, body portion, (b) a pin member axially slidably mounted in said bore (e) said spring means comprising a cup member and spring means carried in said bore urging said pin carried by said pin member, and a spring portion member toward an extended position in which the integrally formed at the inner end of said pin memend of said pin member extends from the end of said ber and received by said cup member. body portion, and 3. A piercing punch member comprising, (6) means disposed entirely within said bore and (a) a body portion having a longitudinal bore, operable upon said body portion being inverted to a (b) a pin member axially slidably mounted in said position in which said pin member extends upwardly bore, from said body portion and upon the end of said pin (0) spring means carried in said bore and urging said member being moved inwardly into said bore to lock pin member toward an extended position in which said pin member in a retracted position in which the the end of said pin member extends from the end of end of said pin member is substantally coplanar with said body portion, the end of said body portion, and (d) means disposed entirely within bore and selec- (d) said last mentioned means including a plurality of tively operable to retain said pin member in a remembers loosely carried within said body portion tracted position in which the end of said pin memand movable to a position intermediate said pin member is substantially coplanar with the end of said body ber and said body portion upon inverting said body portion, portion and retracting said pin member to thereby (e) said spring means comprising a cup member carried lock said pin member in the retracted position.

'at the inner end of said pin member, and a spring member carried in said bore and having one end References Cited seated in said cup member to urge said cup member and said pin member to an extended position. UNITED STATES PATENTS 4. A piercing punch member comprising, 2,917,960 12/ 1959 Gargrave 83-128 (a) a body portion having a longitudinal bore, 3,106,120 10/ 1963 Reece 83-128 (b) a pin member axially slidably mounted in said 3,222,963 12 19 5 Larson bore, 3,255,654 6/1966 Bleicher 83-128 5 WILLIAM S. LAWSON, Primary Examiner.