Abstract: A reciprocating drive mechanism having a housing with upper and lower internal chambers with a spool slidably positioned inside the upper internal chamber. There is at least one fluid inlet and fluid exhaust communicating with the upper internal chamber and at least one slide valve positioned within the upper internal chamber and traveling with the spool. A piston positioned in the lower internal chamber divides the lower internal chamber into an upper and lower cylinder space. A valve stem is connected to the piston and includes a bore communicating with the upper internal chamber and an exhaust passage is positioned between the upper and lower internal chambers.

Abstract: A volume control device having a housing with an inlet passage, an outlet passage, and an internal chamber communicating with the inlet and outlet passages. An accumulator is movably positioned within the internal chamber and substantially conforms with walls of the internal chamber, the accumulator including an internal passage allowing fluid flow therethrough. An one-way valve is positioned in the internal passage of the accumulator where the valve is biased in a closed position and an adjustable seat is positioned within the housing internal chamber between the accumulator and the housing outlet passage. A positioning mechanism engages the housing and adjustable seat whereby the position of the adjustable seat within the housing internal chamber may be adjustably fixed.

Abstract: A reciprocating drive mechanism having a housing with upper and lower internal chambers with a spool slidably positioned inside the upper internal chamber. There is at least one fluid inlet and fluid exhaust communicating with the upper internal chamber and at least one slide valve positioned within the upper internal chamber and traveling with the spool. A piston positioned in the lower internal chamber divides the lower internal chamber into an upper and lower cylinder space. A valve stem is connected to the piston and includes a bore communicating with the upper internal chamber and an exhaust passage is positioned between the upper and lower internal chambers.

Abstract: A reciprocating drive mechanism having a housing with upper and lower internal chambers with a spool slidably positioned inside the upper internal chamber. There is at least one fluid inlet and fluid exhaust communicating with the upper internal chamber and at least one slide valve positioned within the upper internal chamber and traveling with the spool. A piston positioned in the lower internal chamber divides the lower internal chamber into an upper and lower cylinder space. There is at least one fluid conduit communicating between the upper internal chamber and the upper cylinder space and at least one fluid conduit communicating between the upper internal chamber and the lower cylinder space. A valve stem is connected to the piston and includes a bore communicating with the upper internal chamber and an exhaust passage is positioned between the upper and lower internal chambers.