Press having gas cylinders of plastically deformable members for even distribution of blank-holding force on pressure member through cushion pins

A press including (a) force applying means for producing a blank-holding force, (b) a cushion pad which receives said blank-holding force when said cushion pad is moved down, (c) a plurality of cushion pins disposed on said cushion pad, (d) a pressure member supported by said cushion pins at upper ends of the cushion pins remote from said cushion pad, so that said blank-holding force is transferred to said pressure member through said cushion pins to hold a blank placed on said pressure member, when said pressure member is moved down during a pressing operation on said blank, (e) a bolster disposed between said cushion pad and said pressure member and having a plurality of through-holes through which said cushion pins extend, and (f) a lower die disposed on said bolster, and having a plurality of through-holes through which said cushion pins extend, respectively, said press comprising:

• a plurality of mutually independent gas cylinders charged with a gaseous fluid, each of said gas cylinders having a piston fixed to an end of the corresponding one of said cushion pins, said gaseous fluid being compressed during downward movement of said pressure member, so as to establish substantially even distribution of said blank-holding force to said pressure member through all of said plurality of cushion pins,
• each of said mutually independent gas cylinders having an outside diameter not larger than that of said cushion pins, whereby said gas cylinders fixed to said cushion pins are permitted to pass through said through-holes of said lower die upon installation of said gas cylinders together with said cushion pins.

A method of establishing substantially even distribution of a blank-holding force to a pressure member through all of a plurality of cushion pins on a press which includes force applying means for producing said blank-holding force, and a cushion pad which receives said blank-holding force when said cushion pad is moved down, and wherein said cushion pins disposed on said cushion pad, and said pressure member is supported by said cushion pins at upper ends of the cushion pins remote from said cushion pad, so that said blank-holding force is transferred to said pressure member through said cushion pins to hold a blank placed on said pressure member when said pressure member is moved down during a pressing operation on said blank, said method comprising:

• disposing a plurality of plastically deformable members disposed in respective transfer paths of said blank-holding force which correspond to said plurality of cushion pins, respectively;
• and
• effecting downward movement of said pressure member repeatedly so as to apply said blank-holding force to said plastically deformable members for thereby deforming said plastically deformable members, to absorb dimensional and positional errors of the press which cause a variation of length of said transfer paths between said cushion platen and said pressure member, so that the plastic deformation of said plastically deformable members establishes substantially even distribution of said blank-holding force to said pressure member through all of said plurality of cushion pins.