GB602356A - Improvements in hydraulic presses - Google Patents

Abstract

602,356. Hydraulic presses. COX & CO. (WATFORD), Ltd., and HOWARD, T. Aug. 9, 1945, No. 20475. Drawings to Specification. [Class 69 (ii)] In a hydraulic press of the kind in which the movement of the ram is controlled by movement of a treadle or like foot or manually operable member which in turn actuates a plunger or other valve controlling a passage for liquid flow to the press and such that when closed pressure builds up in the cylinder to actuate the ram while when fully open it permits of free circulation of the liquid, thus relieving the pressure in the cylinder and permitting the ram to be returned to inoperative position under the influence of weights or the like, the treadle or treadle bar is connected to a piston or like member movable in a bore in a block or fitting and arranged between upper and lower springs in said bore so that the treadle when released will always return to a neutral position corresponding to a neutral position of the plunger or other valve in which the hydraulic pressure on the ram is equal to the force exerted by the weights or the like for returning the ram so that the ram will remain in any position to which it has been moved. Means are provided for moving the treadle beyond its neutral position against the action of the upper spring when it is desired to return the ram after it has completed its stroke.