Patent ID: 6526879
Filing Date: 2003-03-04
Classification: B30B,F15B

Abstract:
A press comprising:a) an upper platen; b) a lower platen; c) a first and second hydraulic device each including: i) a cylinder; ii) a piston located in the cylinder defining a first and a second chamber in the cylinder, the piston sealingly engaging the cylinder and movable in the cylinder; and iii) a piston rod connected to the piston and extending through the second chamber, wherein the first and second chambers, each have an inlet/outlet for hydraulic fluid and the second chamber of the first hydraulic device is in fluid communication with the first chamber of the second hydraulic device; and wherein each piston rod of each hydraulic device engages one of the upper and lower platens whereby the hydraulic devices are operable to shift, relatively, the platen with which the pistons rods are engaged toward or away from the other platen, d) a pump to pump hydraulic fluid into the first chamber of the first hydraulic device; and e) a valve in fluid communication with the first chambers of the first and second hydraulic devices, wherein said valve is adapted to respond to a pressure in either of said first chambers measured by a sensing means upon a misalignment of said platens, and wherein said valve is adapted to selectively withdraw hydraulic fluid from the first chamber of either or both the first and second hydraulic devices to align the upper and lower platens.