Abstract: A pneumatic control device includes a base comprising a reservoir, a first check valve for only allowing hydraulic fluid to flow into the reservoir, and a second check valve for only allowing the fluid to flow out of the reservoir; a hollow cylinder comprising a spring biased piston; a body mounted to the cylinder thereunder and releasably secured to the base, the body comprising a stepped-diameter passageway with a poppet mounted therein; and a cover releasably secured onto the poppet. In response to feeding pressurized air into the cylinder, the fluid in the reservoir flows out during a first stroke of the piston, and the fluid is sucked back into the reservoir during an opposite second stroke of the piston. In one embodiment, the fluid is for actuating a machine vise.

Abstract: A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

Abstract: The invention concerns an apparatus comprising a body (1) containing a cylinder wherein is mounted sliding an impact piston (1) of a tool, the motion of the piston being controlled by a distributor (15) which, arranged coaxial to the impact piston, is mounted inside a distribution box (3). The distribution box (3) comprises a part axially overlapping the piston (1) and arranged concentric thereto, and the distribution box (3) defines with the piston a control chamber (13) which, successively put under the high (9) and the low (12) pressure of the fluid, communicates through a passage (16) arranged in the distribution box (3) with a chamber controlling (14) the movement of the distributor (15), to generate alternately low pressure and high pressure.

Abstract: The invention concerns an apparatus comprising a body (1) containing a cylinder wherein is mounted sliding an impact piston (1) of a tool, the motion of the piston being controlled by a distributor (15) which, arranged coaxial to the impact piston, is mounted inside a distribution box (3). The distribution box (3) comprises a part axially overlapping the piston (1) and arranged concentric thereto, and the distribution box (3) defines with the piston a control chamber (13) which, successively put under the high (9) and the low (12) pressure of the fluid, communicates through a passage (16) arranged in the distribution box (3) with a chamber controlling (14) the movement of the distributor (15), to generate alternately low pressure and high pressure.

Abstract: There is disclosed a pneumatic driving device having a cylindrical housing in which a piston element is axially displaceable. The piston element has at its ends a front piston and a rear piston which are connected to each other by a connecting pipe. A switch element is mounted in the housing between the pistons and defines a variable front chamber with the front piston and a variable rear chamber with the rear piston. Two inlet openings acted on by pressure are formed in the housing and can be connected with the front and rear chambers respectively. The switch element, in a first position, frees the inlet opening to the rear chamber so that the rear piston travels axially outward and the front piston axially inward and, in a second position, frees the inlet opening to the front chamber so that the front piston moves axially outward and the rear piston axially inward. The inwardly moving pistons reverse the switch element between the two positions.

Abstract: An actuator is driven in a first direction by equal working fluid pressures acting on different piston areas acting in opposite directions, and is driven in a second direction by applying equal pressures on both sides of one of the piston areas. Working fluid from an inlet port, acting in a working fluid chamber, pushes up a valve plate, closes ventilation holes and opens working fluid discharge holes, thereby permitting the working fluid to push the piston upward. Working fluid contained in the working fluid chamber is exhausted from working fluid discharge holes to the outside of the system through a working fluid discharge pipe. When the upward movement of piston reaches its limit, a valve plate is pushed by a spring, thereby causing simultaneous closing of the working fluid discharge holes and the opening of the ventilation holes. As a result of the opened ventilation holes, working fluid pressures in a lower working fluid chamber and an upper working fluid chamber become equal.

Abstract: A vibration generator including an inertial body and a housing which are relatively movable and where hydraulic fluid is directed into the inertial body through a control valve mounted in the inertial body, the fluid being directed alternately into one or another working chamber which causes oscillation of the housing and any attached load. A wave form shape of pressure or flow rate of the hydraulic fluid flow is detected and used to control the frequency at which the vibration generator oscillates so that the frequency is maintained at a resonant frequency. The device has particular application in a frequency range of 20 Hertz to 1000 Hertz.

Abstract: An internal combustion engine, a fluid motor or a pump includes a cylinder block enclosing an elongated cylindrical bore. A double headed piston is slidably mounted within the bore. The piston and cylinder block are rotatable relative to each other about the longitudinal axis of the bore. Rotation is imparted by a sinusoidal cam and a cam follower. Reciprocation of the piston within the bore is accomplished along with corresponding rotational movement of the cylinder block. Opposed ends of the cylinder block include openings which are aligned with and periodically communicate with exhaust and intake chambers. Porting collars are slidably mounted to the cylinder block and are stationary relative to the cylinder.

Abstract: A body support such as a bed, operating table or seat has a flexible top sheet secured over the sides and ends of a frame, and resting on a series of parallel resiliently deformable rollers located between the sides of the frame and supported, in turn, by a longitudinally reciprocal substantially horizontal bearer plate, which is driven back and forth causing the rollers to roll back and forth under the top sheet, thus constantly changing the main pressure areas of the body supported by the top sheet.

Abstract: A hydraulically operated reciprocating piston and a differential force operated valve are both in continuous fluid contact with a pressurized cushion chamber as well as the piston chamber pressure. The valve position is a function of the cushion chamber pressure. The cushion chamber pressure is a function of the axial position of the piston. The values of these functions are such that the piston is reciprocated when the machine is operated. The valve may, for example, be a sleeve coaxial with the piston or a valve transversely spaced from the piston.