Patent ID: 6401513
Filing Date: 2002-06-11
Classification: B21D

Abstract:
A press brake comprising a frame, a bed formed on said frame, a ram displaceable to and away from said bed in a vertical plane, said ram having a lower metal working straight edge disposed in facial relationship and parallel to said bed, said ram being displaceable by a single hydraulic piston secured to and above said ram by opposed symmetrical linkage assemblies, each said linkage assemblies being connected adjacent opposed ends of said ram, each said linkage assemblies including a lever member pivotally secured to said frame by an anchor pin pivot connection (24), a link arm (25) interconnecting said lever member to said ram by pivot pin connections (26-27) adjacent opposed ends of said link arm, a single interconnecting straight bar (21) interconnecting said lever member of each said linkage assemblies together by a further pivot pin connection (28) adjacent opposed ends of said interconnecting bar, said hydraulic piston having a pivot pin connection (19) with said interconnecting bar whereby to axially displace said interconnecting bar in parallel relationship to said lower metal working straight edge to cause said linkage assemblies to pivot in unison on their said anchor pin pivot connection to cause said ram working straight edge to be displaced in substantially perfect parallel relationship with said bed, said symmetrical linkage assemblies having identical pivot pin and anchor pin connections whereby wear of said connections during operation is substantially the same on opposed sides of said ram whereby backlash in said pin connections is subtractive to minimize ram tilt and ensure substantially continuous parallel displacement thereof.