Machine for forming metal stampings having an edge portion folded over on itself

Abstract

A machine for forming metal stampings comprising an upper die holder on which an upper die half and an upper clamping yoke are mounted; a lower die holder on which a lower die half and a lower clamping yoke are mounted; handling means suitable to achieve the bringing together and moving apart of the upper die holder and the lower die holder; and an edge cutting/bending unit suitable to carry out both the cutting and bending of the edge and arranged between the two die halves and the two clamping yokes. The edge cutting/bending unit comprises a cutting blade suitable to cut the edge of a sheet to be formed; an outer bending blade arranged below said cutting blade and which forms a pushing step with it, facing in use towards said upper die half and said lower die half, and an inner bending blade arranged to slide along said outer bending blade.

1 . A machine for forming ( 1 ) metal stampings comprising an upper die holder ( 2 ) on which an upper die half ( 3 ) and an upper clamping yoke ( 7 ) are mounted; a lower die holder ( 4 ) on which a lower die half ( 5 ) and a lower clamping yoke ( 8 ) are mounted; handling means ( 6 ) suitable to achieve the bringing together and moving apart of the upper die holder ( 2 ) and the lower die holder ( 4 ); and an edge cutting/bending unit ( 9 ) suitable to carry out both the cutting and bending of the edge and arranged between the two die halves ( 3 ,  5 ) and the two clamping yokes ( 7 ,  8 ); said edge cutting/bending unit ( 9 ) comprising a cutting blade ( 10 ) suitable to cut the edge of a sheet to be formed; said forming machine ( 1 ) being characterised in that said edge cutting/bending unit ( 9 ) comprises:
 an outer bending blade ( 13 ) arranged below said cutting blade ( 10 ) and which forms a pushing step (G) with it, facing in use towards said upper die half ( 3 ), and   an inner bending blade ( 16 ) arranged to slide along said outer bending blade ( 13 );   said outer bending blade ( 13 ) and said inner bending blade ( 16 ) having two respective toothed surfaces ( 13   a ) and ( 16   a ) interlocked together and arranged to slide against each other; said cutting blade ( 10 ), said outer bending blade ( 13 ) and said inner bending blade ( 16 ) being movable vertically in a mutually independent manner.   
     
     
         2 . The forming machine according to  claim 1 , characterised in that said cutting blade ( 10 ) is attached to a handling plate ( 11 ) which, in turn, is attached to said upper die holder; said upper die holder comprising a plurality of damper pistons ( 12 ) arranged to act in use on the upper die half ( 3 ). 
     
     
         3 . The forming machine according to  claim 1 , characterised in that said cutting blade ( 10 ) is arranged around said upper die half ( 3 ) and said bending blades ( 13 ,  16 ) are arranged around said lower die half ( 5 ). 
     
     
         4 . The forming machine according to  claim 1 , characterised in that said inner bending blade ( 16 ) has an oblique upper surface. 
     
     
         5 . The forming machine according to  claim 1 , characterised in that said cutting blade ( 10 ), said outer bending blade ( 13 ) and said inner bending blade ( 16 ) are connected to respective mutually independent handling means ( 11 ,  6 ,  14 ,  15 ,  17 ,  18 ).