Abstract: A flexible boot surrounds a piston rod and is sealed at one end to the free end portion of the piston rod and at its other end to the rod end of the associated cylinder. The head end of the cylinder is connected to a source of gas under pressure and the interior of the boot communicates freely with the interior of the cylinder at the rod end thereof. A check valve is provided for relieving the pressure in the boot when it reaches a predetermined value.

Abstract: An improved press cushion includes a piston which is disposed within a cylinder chamber. The head end of the cylinder chamber is arranged for communication with a compressed fluid, such as nitrogen gas. The rod end of the cylinder chamber is arranged for communication with a source of air which is free of contaminants found in the immediate environment of the cylinder assembly. Although clean air could be obtained from the atmosphere at a location spaced from the press, the rod end of the cylinder is advantageously connected to a low pressure supply of clean air.

Abstract: In a gas-operated cylinder, the surfaces of the cylinder and piston that are in sliding contact are lubricated by an oil-impregnated wick disposed in an annular chamber at the rod end of the cylinder. The wick extends through radially inwardly extending openings in the chamber to contact the piston rod and also through axial openings in the chamber to contact the back side of the piston when the latter moves to the rod end of the cylinder.

Abstract: A machine for processing metal in sheet or plate form, especially for bending metal sheets. The machine comprises a frame with a table base on the frame and a ram which is vertically displaceable in relation to the table base. The ram has an upper tool, while a lower tool is disposed on the table base, these two tools cooperating to process the metal therebetween. The lower tool is elastically supported on the table base by means of a plurality of individual resilient supports which are arranged in a row on the table base. A plurality of intermediate parts are inserted between the table base and the supports and said parts are displaceable groupwise out of the effective region of selected supports into a neutral position, so that only the supports lying directly under the metal sheet workpiece to be processed are effective.

Abstract: A press system includes an improved valve assembly which is utilized to control a flow of hydraulic fluid from a die cylinder chamber. This valve assembly includes a pair of rigid foraminous members and a resiliently deflectable valve member. The valve member is movable between a closed position extending across and sealing openings in the foraminous members and an open position in which the valve member is spaced apart from the openings to enable hydraulic fluid from the die cylinder chamber to flow through the openings in the foraminous members. The valve member is urged toward the closed position by a compressible fluid, such as nitrogen gas. When the hydraulic fluid pressure in the die cylinder chamber exceeds a predetermined pressure, the valve member is moved from the closed position to the open position against the influence of the biasing pressure applied against the valve member by the compressible fluid.

Abstract: Lubricating means for a piston-cylinder unit operated by non-lubricated gas under pressure comprising a passageway in the piston-cylinder unit extending from the surrounding atmosphere to the cylinder chamber on the side of the piston opposite that to which the pressurized gas is directed. A lubricant-impregnated material is located in the passageway so that, as air flows into said chamber in response to movement of the piston in the cylinder, the lubricant is entrained in the air and is carried into the cylinder to lubricate the contacting surfaces of the piston and cylinder. In addition, a lubricant-impregnated wick is arranged within the piston rod and contacts the conventionally used lubricant-impregnated felt ring on the piston to prolong the supply of lubricant to the ring.

Abstract: Fluid forming apparatus having a constant-volume pressure cavity has oppositely movable rigid forming tool parts, each connected with a piston comprising a double acting cylinder mechanism. Forming pressure is developed by hydraulically forcing one tool part in the direction that tends to reduce cavity volume, thus, by reaction, forcing the other tool part in the opposite direction against restraint. A cam mechanism moving with said one tool part defines a pressure program. Sensor means, cooperating with the cam and with pressure regulating valve mechanism, controls pressure of the fluid driving said one tool part in accordance with the program and the position of that tool part.

Abstract: A die arrangement wherein selected dies are attached to their respective supports by fluid springs in the form of piston-cylinder assemblies which are in turn resiliently mounted on the die supports for pivotal movement as a unit.