Abstract: A pneumatic motor having a motor body having a main piston chamber with opposed first and second chamber ends, at least two spool chambers in fluid communication with the main piston chamber, an inlet for flowing a pressurized fluid into each of the at least two spool chambers, and an outlet provided in the housing for exhausting the pressurized fluid from the main piston chamber and each of the spool chambers. At least two spool members are in the two spool chambers, with each spool member adapted to be movable in a first direction to permit pressurized fluid to be supplied to the main piston chamber and also in a second direction to permit the pressurized fluid to be exhausted from the main piston chamber. A piston member is movable in a reciprocating manner in the main piston chamber in response to movement by the spool members.

Abstract: An improved fluid power actuator assembly comprising a power piston reciprocatingly mounted in a cylinder bore which is formed in a compact fluid power manifold providing the necessary circuit connections between control valves mounted on the housing and the cylinder bore. The cylinder bore includes at least two circumferentially spaced signal ports disposed in the wall of the cylinder bore along the path of travel of the piston in addition to the primary power ports located at each end of the cylinder bore to drive the piston. The piston includes at least one circumferential groove and functions as a spool valve for opening and closing communication between the signal ports as the piston travels in the cylinder. Appropriate control valves and signal pressure communicating with the signal ports is disclosed to enable a fluid power signal to be generated which is related to the position of the piston during its travel in the cylinder bore.

Abstract: A hydraulic pressure amplifier, e.g. for generating high water pressure for rock cutting and the like, in which a differentially displaced piston drives plungers alternately to pressurize the water and is driven by a primary fluid under the exclusively of a hydraulically displaceable pilot valve. The valve member is connected by a single pilot passage to the cylinder of the piston for switching between its positions.

Abstract: Hydraulic fluid pressure moves a piston (22) against a body of incompressible fluid (14), compressing a spring (42). The pressure is released, and the force of the stored energy in the spring (42) is transmitted to the piston (22) by the body of fluid (14) and drives the piston (22) through its power stroke. The fluid (14) is vented to an outlet (8) before the piston (22) reaches the end of its power stroke, removing the force from the piston (22) and allowing it to free travel through the remainder of the stroke. When the motor (2) is operating and the load is removed from the piston (22), the hydraulic fluid inlet (10) is short-circuited to the outlet (8) and the motor (2) automatically shuts off.

Abstract: An air driven diaphragm pump having an actuator valve for converting a source of compressed air into a reciprocating drive. The actuator valve includes a valve piston for alternately directing air to one side or the other of the pumps, a control rod fixed to the reciprocating elements of the pump and means for shifting the valve piston responsive to the position of the control rod. An axially spaced bifurcated inlet is employed to provide additional energy to the shifting of the valve piston. The valve piston also is arranged to cover vent ports as a mechanism for closing off all compressed air under stalled conditions of the pump.

Abstract: A hydraulic oscillator in which a piston reciprocates between first and second positions in a cylinder. A reversing pilot valve controls fluid flow to ends of the cylinder and flow through first and second pilot passages control the reversing operation of the pilot valve. The cylinder has a pilot channel or groove coupled to a pilot supply line. The piston has (1) a first logic channel for fluidly coupling the pilot channel and first pilot passage as the piston approaches the second position and (2) a second logic channel for fluidly coupling the pilot channel and second pilot passage as the piston approaches the first position thereby to alternately reverse the pilot valve and produce the reciprocation of the piston.

Abstract: A hydraulic percussive machine comprising a piston and cylinder with a dashpot at the front end to cushion overtravel of the piston. Heat is removed from the dashpot by admitting pressure fluid to the return stroke chamber through a front chamber and the dashpot. On the pressure stroke fluid from the return stroke chamber is admitted to the working stroke chamber in one case by causing all flow to take place along that route and in the other place by having two feeds to the working stroke chamber with a flow restrictor in the direct feed line.

Abstract: A control valve for alternately applying fluid pressure to two drive members of a reciprocating work device such as a pump. A valve piston is slideable in a closed cylinder to which pressurized fluid is transmitted. The valve piston, controls the fluid depending on the position of the piston in its cylinder, to pressurize one chamber and vent the other so as to move the work device in one direction or the other. In turn, the work device controls the fluid to position the valve piston.

Abstract: In a hydraulic striking device having a reciprocating piston there are first and second cylindrical spaces surrounding the piston, the first space continuously communicating with a high pressure circuit and the second space alternately communicating with the high pressure circuit and a low pressure circuit. A special sleeve-shaped control valve in the second space reciprocates axially of the piston to achieve the desired operation.

Abstract: A striking apparatus has a body which carries a tool and which has a cylinder space, a piston structure within the space, and a sleeve-type distributor valve within the cylinder and around the piston. Flow of hydraulic fluid supplied to the body under pressure is controlled by the valve and piston to cause the piston to reciprocate, striking the tool. The sleeve valve has an extension portion which controls flow through a canal in the piston to a valve operating distributor space and limits flow of liquid under pressure to an outlet canal to a relatively short interval in the operating cycle, thereby reducing the amount of liquid wasted.

Abstract: A hydraulic impact tool wherein hydraulic power is used to lift a ram against a bias to store energy and wherein the ram then is permitted to accelerate toward an impliment to which it imparts energy upon impact. A reciprocating cylindrical sleeve slidable about the ram is arranged to control the hydraulic fluid. The sleeve is initially carried in each direction by the ram and is shifted relative to the ram by hydraulic power.

Abstract: Hydraulically driven percussion device, comprising a piston reciprocally movable within a body and striking against a tool, said piston defining with reference to the body two cylinder spaces, one of which continuously communicates with the high pressure duct and the other by the aid of a distribution means alternatingly connectable to the high pressure duct and the low pressure duct. At both ends of the piston there are breathing chambers opening into the free atmosphere. Within one of said two cylinder spaces a sleeve-like distribution means has been placed to encircle the piston and which distribution means, in order to move into a position such that movement of the piston directed towards the tool becomes possible, is controlled by means of grooves provided in the piston and in the body when the piston is in its end position farthest removed from the tool and only on condition that the pressure in the high pressure duct exceeds a pressure set with an adjustable valve incorporated in the body.