Abstract A hydraulic press brake is disclosed having a stationary die cooperating with a movable die or punch to perform a bending operation on an elongated workpiece. Movement of the punch is effected by means of a pair of first hydraulic piston-cylinder units each of which is located proximate to one end of the punch. At least one second hydraulic piston-cylinder unit acts on the stationary die at a location intermediate the ends thereof to impart a convex bend to the fixed die to compensate for any concave bending of the movable die during a bending operation, thereby maintaining the surfaces of the fixed and movable dies substantially parallel. Pressurized hydraulic fluid is fed to the first and second hydraulic piston-cylinder units through feed conduits leading from a common pump, with a pressure reducing valve being interposed in the feed conduits between the pump and the second hydraulic piston-cylinder unit.
Inventors
👤 Susumu Kawano
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-07 05:36
CPC Classifications
B; B21; B21D; B21D5/00; B21D5/02; B21D5/0272
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
204 words
A hydraulic press brake comprising: stationary frame means supporting an elongated die; movable ram means carrying an elongated punch, said punch being adapted to cooperate with said die in performing a bending operation on an elongated workpiece positioned therebetween; first hydraulically actuated means acting on said movable ram means at locations proximate to the ends thereof for moviNg said ram means and punch towards said stationary frame and elongated die during a bending operation; second hydraulically actuated means acting on said stationary frame means at a location intermediate the ends of the die supported thereon, said second hydraulically actuated means being operative to bend said stationary frame means and die convexly to thereby compensate for concave bending of said punch and ram means during a bending operation; hydraulic pump means; conduit means connecting said hydraulic pump means to said first and second hydraulically actuated means; and pressure reducing valve means in said conduit means between said pump means and said second hydraulically actuated means, said pressure reducing valve means being operative to reduce the pressure of the hydraulic fluid being applied to said second hydraulically actuated means in proportion to the pressure of the hydraulic fluid being applied to said first hydraulically actuated means.
Claim 2
Dependent Claim
204 words
A hydraulic press brake comprising: stationary frame means supporting an elongated die; movable ram means carrying an elongated punch, said punch being adapted to cooperate with said die in performing a bending operation on an elongated workpiece positioned therebetween; first hydraulically actuated means acting on said movable ram means at locations proximate to the ends thereof for moviNg said ram means and punch towards said stationary frame and elongated die during a bending operation; second hydraulically actuated means acting on said stationary frame means at a location intermediate the ends of the die supported thereon, said second hydraulically actuated means being operative to bend said stationary frame means and die convexly to thereby compensate for concave bending of said punch and ram means during a bending operation; hydraulic pump means; conduit means connecting said hydraulic pump means to said first and second hydraulically actuated means; and pressure reducing valve means in said conduit means between said pump means and said second hydraulically actuated means, said pressure reducing valve means being operative to reduce the pressure of the hydraulic fluid being applied to said second hydraulically actuated means in proportion to the pressure of the hydraulic fluid being applied to said first hydraulically actuated means.
Claim 3
Dependent Claim
18 words
The apparatus as claimed in claim 1 wherein said first and second hydraulically actuated means comprise piston-cylinder assemblies.