Pump fluid motor carrying spool valve for distributor valve actuation

In a fluid engine having a single acting cylinder for converting the pressure energy of an operating fluid to reciprocating actuation of a piston in a cylinder chamber, a directional control valve which alternately connects the cylinder chamber to an operating fluid inlet port, to force the piston downward by the pressure of the operating fluid against a spring biasing force, and to an operating fluid outlet, to permit return of the piston upwardly by the spring biasing force, and a master valve to operate the directional control valve, the improvement comprising:

• a. a piston rod on said piston,
• b. a spool on said piston rod,
• c. a reciprocably movable disc comprising said control valve, and said piston rod passing through said disc, and
• d. a pair of valve seats in said master valve additionally forming packings, one of said valve seats being in said disc and the other exterior of said disc, said pair of valve seats cooperating with said piston rod and its spool to alternately perform simultaneous respective sealing and unsealing of operating fluid to effect a reciprocation of the disc, thereby either permitting operating fluid to enter the cylinder chamber or venting operating fluid from the cylinder chamber, so as to cause movement of said piston.