Lower mold assembly for punching a sheet

Abstract

A lower mold assembly for punching a sheet comprises a lower mold body having an upper surface; a V shape trench is formed at the upper side of the lower mold body; each lateral wall of the trench being formed with a recess; each recess being installed with an elastic element; a punching knife being installed above the lower mold body; the hardness of the elastic elements being slightly smaller than that of the lower mold body; wherein the elastic element serves to increase the tightness in punching operation and to avoid the punching traces in punching operation. A width of the lower mold body is adjustable based on a width of a sheet placed thereupon for punching. The elastic element has an irregular surface. The elastic element is made of a material selected from one of POM and elastic hard rubber.

What is claimed is: 
     
         1 . A lower mold assembly for punching a sheet; the assembly comprising: a lower mold body having an upper surface; a V shape trench being formed at the upper side of the lower mold body; each lateral wall of the trench being formed with a recess; each recess being installed with an elastic element; a punching knife being installed above the lower mold body; the hardness of the elastic elements being slightly smaller than that of the lower mold body; wherein the elastic element serves to increase the tightness in punching operation and to avoid the punching traces in punching operation. 
     
     
         2 . The lower mold assembly for punching a sheet as claimed in  claim 1 , wherein a width of the lower mold body is adjustable based on a width of a sheet placed thereupon for punching. 
     
     
         3 . The lower mold assembly for punching a sheet as claimed in  claim 1 , wherein the elastic element has an irregular surface. 
     
     
         4 . The lower mold assembly for punching a sheet as claimed in  claim 1 , wherein the elastic element is made of a material selected from one of POM and elastic hard rubber.