Punching apparatus for stamping and method for producing the same

Abstract

A stamping punch of a punching apparatus including a grip member provided with crosspieces formed between long grooves on side walls of a rectangular parallelepiped, and a plurality of punch members which are formed integrally with the grip member. The respective punch members are arranged in parallel to one another. A plurality of holes are defined on a punch holder. A large amount of adhesive is contained in the gap between joining surfaces when the grip members of the stamping punches are inserted and secured into the respective holes. Accordingly, the positional accuracy of the punch member is improved, the accuracy of the hole defined through a workpiece is improved, and it is possible to eliminate any fear of occurrence of defect in shape. Further, the rigidity of the punch member can be improved, the stripper is prevented from application of unbalanced load, and the punch is easily exchangeable.

What is claimed is:  
     
         1 . A method for producing a punching apparatus for stamping comprising a punch holder secured to an upper die, a die member secured to a lower die, a plurality of grip members detachably fastened to said punch holder, and said plurality of punch members formed on each of said plurality of grip members, said method comprising said steps of: 
 using a prism-shaped block as a material for said grip member and said punch members;    machining a plurality of parallel long grooves separated from each other by arbitrary spacing distances on two opposing side walls of said prism-shaped block;    machining tops of crosspieces formed between said long grooves to have a circular arc-shaped configuration;    machining long grooves having an arbitrary depth on another side wall so that said long grooves communicate with said long grooves on said two side walls;    simultaneously forming thereby said grip member including said plurality of long grooves and said circular arc-shaped crosspieces formed between said long grooves provided on said two opposing side walls and said plurality of punch members each having a lengthy rectangular cross section with its both ends provided with circular arc-shaped portions; and    defining a plurality of holes each having a rectangular cross section on said punch holder on the other hand, wherein: 
 said grip member is fitted to said punch holder with a gap such that said crosspieces formed on said side walls of said grip member slidably contact with side walls of said hole of said punch holder.  
   
     
     
         2 . The method for producing said punching apparatus for stamping according to  claim 1 , wherein said circular arc-shaped top of said crosspiece formed on said side wall of said grip member and said circular arc-shaped portion of said punch member are deformed to include flat portions.