Punch stripper and press tool

Abstract

A punch stripper is adapted to be fastened to a punch retainer of a press tool, and to retain a work piece as the piece is being machined by a punch. The punch stripper includes a punch stripper piston and a pressure chamber adapted to spring-load the punch stripper piston. The pressure chamber is at least partially defined by a gap between an inner sleeve and an outer sleeve. The punch stripper piston has a portion that is axially displaceable in the gap.

1 . A punch stripper adapted to be fastened to a punch retainer of a press tool comprising a punch stripper piston and a pressure chamber, said pressure chamber designed to spring-load said punch stripper piston, said pressure chamber at least partially defined by a gap between an inner sleeve and an outer sleeve, said punch stripper piston having a displaceable portion that is axially displaceable in said gap, substantially the whole pressure chamber is located between said inner sleeve and said outer sleeve.  
   
   
       2 . The punch stripper as defined in to  claim 1 , wherein said pressure chamber includes a guide portion and a chamber portion, said guide portion is designed to enable said displaceable portion of said puncher stripper to move therein, said chamber portion axially separated from said guide portion, said chamber portion having a larger cross-sectional area than said guide portion.  
   
   
       3 . The punch stripper as defined in  claim 2 , wherein said outer sleeve has a first portion and second portion, said first portion having a first inner cross section that forms a boundary surface of said guide portion of said pressure chamber, said second portion having a second inner cross section, at least a portion of said second inner cross section being greater than at least a portion of said first inner cross section, said second portion forming a boundary surface of said chamber portion of said pressure chamber.  
   
   
       4 . The punch stripper as defined in  claim 3 , wherein said first inner cross section has an average cross-sectional area, said second inner cross section having an average cross-sectional area, said average cross-sectional area of said second inner cross section greater than said average cross-sectional area of said first inner cross section.  
   
   
       5 . The punch stripper as defined in  claim 3 , wherein said first inner cross section has a substantially constant cross-section area.  
   
   
       6 . The punch stripper as defined in  claim 2 , wherein the inner sleeve includes a first portion and a second portion, said first and second portions axially spaced from one another, said first portion forming a boundary surface of said guide portion of said pressure chamber, said second portion forming a boundary surface of said chamber portion of said pressure chamber, at least a portion of said first and second portions of said inner sleeve having different cross-sectional areas.  
   
   
       7 . The punch stripper as defined in  claim 3 , wherein the inner sleeve includes a first portion and a second portion, said first and second portions axially spaced from one another, said first portion forming a boundary surface of said guide portion of said pressure chamber, said second portion forming a boundary surface of said chamber portion of said pressure chamber, at least a portion of said first and second portions of said inner sleeve having different cross-sectional areas.  
   
   
       8 . The punch stripper as defined in  claim 5 , wherein the inner sleeve includes a first portion and a second portion, said first and second portions axially spaced from one another, said first portion forming a boundary surface of said guide portion of said pressure chamber, said second portion forming a boundary surface of said chamber portion of said pressure chamber, at least a portion of said first and second portions of said inner sleeve having different cross-sectional areas.  
   
   
       9 . The punch stripper as defined in  claim 8 , wherein said cross-sectional area of said first portion of said inner sleeve is substantially constant.  
   
   
       10 . The punch stripper as defined in  claim 9 , wherein at least a portion of said cross-sectional area of said second portion is greater than said cross-sectional area of said first portion.  
   
   
       11 . The punch stripper as defined in  claim 1 , wherein said inner sleeve is fixed relative to said punch.  
   
   
       12 . The punch stripper as defined in  claim 10 , wherein said inner sleeve is fixed relative to said punch.  
   
   
       13 . The punch stripper as defined in  claim 1 , wherein said outer sleeve is fixed relative to said punch.  
   
   
       14 . The punch stripper as defined in  claim 12 , wherein said outer sleeve is fixed relative to said punch.  
   
   
       15 . The punch stripper as defined in  claim 1 , wherein said displaceable portion of said punch stripper piston is sealed with respect to said inner sleeve, said outer sleeve, or combinations thereof.  
   
   
       16 . The punch stripper as defined in  claim 14 , wherein said displaceable portion of said punch stripper piston is sealed with respect to said inner sleeve, said outer sleeve, or combinations thereof.  
   
   
       17 . The punch stripper as defined in  claim 1 , wherein said punch stripper piston at least partially includes a rotation inhibiting arrangement to inhibit or prevent said punch stripper piston from rotating relative to said inner sleeve, said outer sleeve, or combinations thereof.  
   
   
       18 . The punch stripper as defined in  claim 16 , wherein said punch stripper piston at least partially includes a rotation inhibiting arrangement to inhibit or prevent said punch stripper piston from rotating relative to said inner sleeve, said outer sleeve, or combinations thereof.  
   
   
       19 . The punch stripper as defined in  claim 1 , including a pressure indicating arrangement to indicate a pressure in said pressure chamber.  
   
   
       20 . The punch stripper as defined in  claim 18 , including a pressure indicating arrangement to indicate a pressure in said pressure chamber.  
   
   
       21 . The punch stripper as defined in  claim 20 , wherein said pressure indicating arrangement is designed to indicate that a pressure in said pressure chamber exceeds a predetermined value, falls below a predetermined value, or combinations thereof.  
   
   
       22 . The punch stripper as defined in  claim 20 , wherein said pressure indicating arrangement is formed integrally with said punch stripper.  
   
   
       23 . The punch stripper as defined in  claim 21 , wherein said pressure indicating arrangement is formed integrally with said punch stripper.  
   
   
       24 . The punch stripper as defined in  claim 20 , wherein said pressure indicating arrangement includes a spring-loaded part which is at least partially visible from an outside of said punch stripper.  
   
   
       25 . The punch stripper as defined in  claim 23 , wherein said pressure indicating arrangement includes a spring-loaded part which is at least partially visible from an outside of said punch stripper.  
   
   
       26 . The punch stripper as defined in  claim 1 , wherein said punch stripper is at least partially connected to a press tool by a punch retainer.  
   
   
       27 . The punch stripper as defined in  claim 25 , wherein said punch stripper is at least partially connected to a press tool by a punch retainer.  
   
   
       28 . The punch stripper as defined in  claim 26 , wherein said punch retainer is at least partially fastened to a stroke part of the press tool.  
   
   
       29 . The punch stripper as defined in  claim 27 , wherein said punch retainer is at least partially fastened to a stroke part of the press tool.  
   
   
       30 . The punch stripper as defined in  claim 26 , including a second punch stripper connected to the press tool.  
   
   
       31 . The punch stripper as defined in  claim 29 , including a second punch stripper connected to the press tool.  
   
   
       32 . The punch stripper as defined in  claim 30 , wherein pressure chambers of said two punch strippers are in fluid communication with one another.  
   
   
       33 . The punch stripper as defined in  claim 31 , wherein pressure chambers of said two punch strippers are in fluid communication with one another.  
   
   
       34 . The punch stripper as defined in  claim 33 , wherein said pressure in said pressure chambers of said two punch strippers are substantially the same.  
   
   
       35 . A punch stripper adapted to be fastened to a punch retainer of a press tool comprising a punch stripper piston, a pressure chamber and a pressure indicating arrangement, said pressure chamber designed to spring-load said punch stripper piston, said pressure chamber at least partially defined by a gap between an inner sleeve and an outer sleeve, said punch stripper piston having a displaceable portion that is axially displaceable in said gap, said pressure indicating arrangement to indicate a pressure in said pressure chamber.  
   
   
       36 . The punch stripper as defined in  claim 35 , wherein said pressure indicating arrangement is designed to indicate that a pressure in said pressure chamber exceeds a predetermined value, falls below a predetermined value, or combinations thereof.  
   
   
       37 . The punch stripper as defined in  claim 35 , wherein said pressure indicating arrangement is formed integrally with said punch stripper.  
   
   
       38 . The punch stripper as defined in  claim 36 , wherein said pressure indicating arrangement is formed integrally with said punch stripper.  
   
   
       39 . The punch stripper as defined in  claim 35 , wherein said pressure indicating arrangement includes a spring-loaded part which is at least partially visible from an outside of said punch stripper.  
   
   
       40 . The punch stripper as defined in  claim 35 , wherein said pressure indicating arrangement includes a spring-loaded part which is at least partially visible from an outside of said punch stripper.  
   
   
       41 . The punch stripper as defined in  claim 39 , wherein said pressure indicating arrangement includes a spring-loaded part which is at least partially visible from an outside of said punch stripper.