Abstract: A pressure releasing valve structure 36? is provided for a fluid operated device 10. The device has an orifice 42 constructed and arranged to be in fluid communication with a pressure chamber C. The valve structure includes a body 49 having first and second ends. A valve member 40 is provided at the first end of the body and is constructed and arranged to seal the orifice 42. A first spring 38 is associated with the first end of the body and is constructed and arranged to cause the valve member 40 to seal the orifice 42 under first pressure conditions in the pressure chamber C. A second spring 50 is associated with the second end of the body and is constructed and arranged to compress thereby reducing a force exerted by the first spring 38, permitting the valve member 40 to move to a non-sealing position to open the orifice under pressure conditions in the pressure chamber C lower than would be required absent the provision of the second spring.

Abstract: A bi-stable valve arrangement includes a body having first and second opposing ends and constructed and arranged to define a passage between the body and another element so that the passage extends from the first end to the second end. A seal member associated with the body. A first spring structure biases the seal member in a first direction and a second spring structure biases the seal member in a direction opposite the first direction. The first and second spring structures are constructed and arranged so that the seal member may seal the passage.

Abstract: A hydraulic device includes a housing and a bulkhead disposed in the housing. A pump piston is provided in the housing and has first and second end surfaces with the second end surface of the pump piston and surfaces of the housing and of the bulkhead defining a pumping chamber. The pump piston is constructed and arranged to move within the housing to develop pressure on fluid in the pumping chamber. The first end surface of the pump piston and surfaces of the housing define a pump reservoir chamber. A ram piston is provided in the housing and has first and second end surfaces with the first end surface of the ram piston and surfaces of the housing and of the bulkhead defining a drive chamber. Connecting structure is associated with the bulkhead to communicate the pumping chamber with the drive chamber so that fluid pressure developed in the pumping chamber may be exerted on the first end surface of said ram piston. A barrier is provided in the housing between an end of the housing and the ram piston.