Punch and stripper assembly

Abstract

A Punch and Stripper Assembly for use in a punch press includes a punch with a shoulder at an intermediate portion thereof, a head threaded onto an end of the punch for being engaged by the ram of the press, a compression spring engaging the head, a washer engaging the opposite end of the spring, a retainer acting between the punch shoulder and the washer, and a stripper sleeve for acting between the workpiece and the retainer, whereby the position of the head on the punch provides a preload to maximize spring life, as well as to control the effective height of the assembly with respect to the ram. With this assembly, no special tooling is needed to assemble it. The retainer can be inverted to alter the retractive position of the punch shoulder. .Iadd.

I claim as my invention: 
     
       1. A punch and stripper assembly for use with a die on a workpiece beneath the ram of a punch press, comprising: a. a punch having means at one end thereof for coacting with said die, an intermediate body portion, a shoulder facing away from said one end, and a threaded end portion at the opposite end;   b. an enlarged head adjustably carried on said threaded end portion for being engaged by the ram;   c. a compression spring surrounding said opposite end of said punch, and at one end engaging said head;   d. a washer surrounding said punch and engaging the opposite end of said spring;   e. a retainer acting between said punch shoulder and said washer, and held in engagement therewith by said spring; and   f. a stripper sleeve surrounding said body portion of said punch for transferring a reactive force from the workpiece to said retainer during a power stroke of the punch press to store energy in said spring.   
     
     
       2. A punch and stripper assembly according to claim 1, said retainer slidably engaging a reduced diameter portion of said punch extending from said punch shoulder. 
     
     
       3. A punch and stripper assembly according to claim 2, said retainer being a split ring deformed onto said reduced diameter portion of said punch. 
     
     
       4. A punch and stripper assembly according to claim 2, said retainer being a solid ring deformed onto said reduced diameter portion of said punch. 
     
     
       5. A punch and stripper assembly according to claim 2, said retainer being a split ring comprising two separate sections jointly surrounding said reduced diameter portion of said punch, and said washer having a counterbore in which said retainer sections are at least partially disposed. 
     
     
       6. A punch and stripper assembly according to claim 5, said retainer having a cylindrical projection of reduced diameter at one side thereof for extending axially beyond said counterbore into said washer, and, when inverted, for engaging said shoulder and for extending axially into said sleeve. 
     
     
       7. A punch and stripper assembly according to claim 1, including a second retainer acting between said sleeve and said punch for holding them in assembled relation when the assembly is out of the punch press. 
     
     
       8. A punch and stripper assembly according to claim 7, said second retainer being a spring substantially encircling said sleeve and having an end projecting through said sleeve for engagement with a second shoulder on said punch. 
     
     
       9. A punch and stripper assembly according to claim 1, including means firmly encircling said sleeve adjacent to said retainer to which a lifting force is to be applied for said assembly from said punch press. 
     
     
       10. A punch and stripper assembly according to claim 9, said encircling means being a spring encircling said sleeve in a groove. .Iadd. 11. A punch and stripper assembly for use in association with a punching device which receives the punch and stripper assembly comprising: an elongated punch body having a cutting end and a heat end, at least one recess in said body intermediate said ends, a head member affixed to said head end, a stripper sleeve slidably received over said cutting end and surrounding intermediate portions of said body intermediate said ends, said sleeve movable with respect to said punch body, a washer positioned between said sleeve and said head, a stripper spring positioned between said head and said washer urging said washer towards sleeve, retainer means for retaining the sleeve on the punch including a substantially radial aperture through the sleeve alignable with the recess in the body portion of the punch, a circumferential groove in an exterior of the sleeve open to the aperture, a retainer portion in the aperture, spring means in the groove maintaining the retainer portion in the aperture, said spring means extending radially outwardly of the sleeve, said spring means forming a radially projecting abutment surface against which an axial lifting force is to be applied from said device for lifting the assembly said surface extending radially outwardly beyond an outer diameter surface of the sleeve, and sleeve encircling lifter means on said punching device having a sleeve receiving opening therethrough with an inner diameter less than an outer diameter of the spring means and a face contacting the spring means applying the lifting force to the spring means. .Iaddend. .Iadd. 12. The device of claim 11 wherein the lifting force is transmitted from the spring means to the sleeve and from the sleeve to the washer. .Iaddend..Iadd. 13. The device of claim 12 wherein the sleeve is freely received on the punch body and is retained thereon by the retainer portion projecting into the recess, said projection of the retainer portion maintained by said spring means. .Iaddend. .Iadd. 14. A punch and stripper assembly for use in association with a punching device which receives the punch and stripper assembly comprising: an elongated punch body having a cutting end and a head end, at least one recess in said body intermediate said ends, a head member affixed to said head end, a stripper sleeve slidably received over said cutting end and surrounding intermediate portions of said body intermediate said ends, said sleeve movable with respect to the said punch body, a washer positioned between said sleeve and said head, a stripper spring positioned between said head and said washer urging said washer towards sleeve, retainer means for retaining the sleeve on the punch including a substantially radial aperture through the sleeve alignable with the recess in the body portion of the punch, a circumferential groove in an exterior of the sleeve open to the aperture, a retainer portion in the aperture, spring means in the groove maintaining the retainer portion in the aperture, said spring means extending radially outwardly of the sleeve, said spring means forming an abutment surface against which an axial lifting force is to be applied from said device for lifting the assembly, the lifting forces transmitted from the spring means to the sleeve and from the sleeve to the washer, the sleeve is freely received on the punch body and is retained thereon by the retainer portion projecting into the recess, said projection of the retainer portion maintained by said spring means, the punch body is provided with a substantially radial shoulder intermediate the ends thereof facing away from said cutting end, the washer having a bore therethrough having an enlarged bore section open to an axial end thereof communicating internally of the washer with a reduced bore section, the punch body received through said bore, a retainer member in said enlarged bore section, said retainer acting between a punch body shoulder and said washer and held in engagement therewith by said stripping spring whereby a reactive force from a workpiece being acted upon by said punch and stripper assembly is transferred from said sleeve to said washer to store energy in said spring. .Iaddend. .Iadd. 15. A punch and stripper assembly for use with a die on a workpiece beneath the ram of a punch press comprising: a. a punch having means at one end thereof for coacting with said die, an intermediate body portion shoulder facing away from said one end, and a threaded end portion at the opposite end;   b. an enlarged head adjustably carried on said threaded end portion for being engaged by the ram;   c. a compression spring surrounding said opposite end of said punch, and at one end engaging said head;   d. a washer surrounding said punch and engaging the opposite end of said spring;   e. a retainer acting between said punch shoulder and said washer, and held in engagement therewith by said spring;   f. a stripper sleeve surrounding said body portion of said punch for transferring a reactive force from the punch to said retainer during the power stroke of the punch press to store energy in said spring;   G. a second retainer acting between said sleeve and said punch for holding them in assembled relation when the assembly is out of the punch press, said second retainer including a spring member substantially encircling said sleeve in a sleeve groove and a second retainer portion projecting through said sleeve for engagement with a second shoulder on said punch, the spring member maintaining the second retainer portion in an aperture through said sleeve and urging the said second retainer portion radially inwardly, said spring member providing abutment means to which a lifting force is to be applied for said assembly from said punch press;   h. and lifting means received around said sleeve when said assembly is in position in said punch press, said lifting means engaging said spring. .Iaddend. .Iadd. 16. A punch and stripper assembly for use in association with a punching device which receives the punch and stripper assembly comprising: an elongated punch body having a cutting end and a head end, a head member affixed to said head end and axially adjustable thereon, a washer member interposed between said head end and said cutting end, a stripper spring between said head and said washer, means retaining said washer on said punch body, a stripper sleeve received around the cutting end portion of said punch body, said stripper sleeve being positioned with respect to said washer to transmit an axial force applied to said stripper sleeve through said washer to said spring to store energy in said spring, the adjustability of said head on said body providing a preload of said stripper spring, the means retaining the washer on the said punch body limiting movement of the washer axially of the body away from the said load member and said stripper spring whereby the preload is maintained, the washer being axially movable on the punch body away from the cutting end, the means retaining the washer on the spring comprises a ledge formed on said punch body intermediate said ends, a retainer member interposed between said ledge and radial face of said washer, the preload urging the washer against the retainer and the retainer against the ledge. .Iaddend. .Iadd. 17. The device of claim 16 wherein the retainer is a ring member circumferentially received around the punch body. .Iaddend..Iadd. 18. The device of claim 17 wherein the retainer is seated in an enlarged bore section of a bore through the washer, the bore receiving the punch body, the retainer engaging a ledge face of the washer formed at the enlarged bore section. .Iaddend..Iadd. 19. The device of claim 18 wherein the retainer is a multi-piece ring member and wherein the punch body ledge is formed as a face of a diameter reducing portion of the punch body. .Iaddend.