Abstract: A forward-moving inching unit and a backward-moving inching unit are built in a casing (1) which is slidable relative to a guide member (b).

Abstract: A piston machine has two pistons which reciprocate in two cylinders. The cylinders define working chambers in which a working medium can either be compressed by the pistons or can exert pressure on the pistons. The pistons are connected to a crankshaft via two connecting rods which are pivotally connected to the same crank pin. The interior of the crankcase forms a third working chamber. The crankshaft is formed as a rotary slide valve which, in operation, connects the first working chamber to the third working chamber and the second working chamber to a working medium supply or discharge opening. The piston machine can be used either as an engine (such as an expansion motor driven by compressed gas) or as a working machine (such as a machine which produces compressed gas). In another embodiment, the rotary slide valve has a rotor which is formed by the crankcase and a stator which is a ring housing.

Abstract: A power cylinder (10) has two pistons (12, 20) slidably mounted within separate cylinders (14, 22) to define inner and outer chambers (16, 18; 24, 26) within each cylinder. One or more rods (28) are coupled between the pistons. The outer chambers (18, 26) are coupled together to allow pressurized hydraulic or pneumatic fluid to flow therebetween. The inner chambers (16, 24) are coupled together to allow pressurized hydraulic or pneumatic fluid to flow therebetween. The fluid flow aforesaid may be achieved by using two hollow rods (128, 130) and allowing the fluid to flow through the rods between the respective chambers. A guard (44) may surround first and second cylinders (14, 22). Bearings (46, 48) may be fixed around the opposed inner ends of cylinders (14, 22) to allow slidable displacement of the cylinders relative to guard (44).

Abstract: A plurality of piston heads (P1, P2, P3) are spaced apart along the length of a single piston rod (R). A separate traveling cylinder body (CB1, CB2, CB3) is associated with each piston head (P1, P2, P3). The traveling cylinders bodies (CB1, CB2, CB3) and the piston heads (P1, P2, P3) define first fluid chambers (1A, 2A, 3A) on a common side of the piston heads (P1, P3, P3) and a set of second fluid chambers (1B, 2B, 3B) on a common opposite side of the piston heads (P1, P2, P3). A separate fluid supply and return passageway is provided within the piston rod (R) for each of the working chambers (1A, 1B, 2A, 2B, 3A, 3B). Center members (C1, C2, C3) are secured within the hollow interior of the piston rod (R) and serve to divide the hollow interior into four axial sections (122, 124, 126, 128). The piston rod (R) includes first and second end members (RE1, RE2).

Abstract: A hydraulically-operated support device for semitrailers is disclosed comprising a hydraulic cylinder semitrailer support and a pump subassembly having three independently operable pumps for generating and controlling the hydraulic operating pressure. The hydraulic cylinder semitrailer support has an extending piston in an extending cylinder, in the bottom end of which is formed a load-raising cylinder for a load raising-piston. A first annular space is formed between the extending piston and the extending cylinder and a second annular space is formed between the load-raising piston and the load-raising cylinder. The annular spaces allow application of pressure in the retraction direction. The pump subassembly comprises an extending pump acting on the extending piston, a load-raising pump acting on the load-raising piston and a retracting pump acting on the annular spaces.

Abstract: A hydraulically powered reciprocating downhole pump having improved means for reliable and efficient operation is disclosed in which a reversing valve (8) is hydraulically shifted past center position so as to effect a smooth continuous operation. Inlet valves (5) and outlet valves (86) are provided so as to most fully utilize space available within diameter constraints for rapid and efficient operation.

Abstract: Situated between the opposite end walls (13, 13') of a fixed steering casing (10) is a hollow rod (14) carrying a fixed piston (16) on which a cylinder assembly (50, 51) slides, on which is elastically mounted, through the intermediary of elastic components (34), a rack block (30) meshing with a pinion (20) which is coupled to the output component of a distribution valve (40).

Abstract: A supplemental brake system operates in cooperation with a motor vehicle's extant emergency brake system for selectively slowing a spinning wheel. A selector valve communicates with the vehicle's vacuum system and conduits are sized to cause a delay in the slowing of the spinning wheel. Further, the system provides for the gradual extension of the emergency brake cables which is unaffected by changes in vacuum levels in the vacuum system. The operator has full control of the vehicle during the system's operation.

Abstract: The invention provides a hydraulic servo-control device which performs the same functions as a conventional device but is much cheaper to manufacture and maintain.For this purpose, the control device comprises a cylinder device formed by a cylinder and a piston rigid with a rod and a hydraulic control unit whose body is rigid with the cylinder. The body of the hydraulic control unit defines a cavity for receiving the cylinder of the cylinder device and this cylinder is made in two main parts, namely a case partly received in the cavity and fixed to the body of the hydraulic control unit, and a tubular sleeve which is axially and radially positioned inside the case and the cavity and cooperates with the piston.Application in particular in the control of the pitch of the blades of a helicopter or the ailerons of a light aircraft.

Abstract: The device comprises a directional valve body which is movable with respect to guide means, and a spool which is slidably mounted in the body and connected to a control lever. The latter is pivotally mounted on a pin which is fixed relative to the body. This pin is carried by a support which is mounted on the body and means are provided for adjusting the position of the support relative to the body.

Abstract: A power assist device for a control system to amplify force to assist in movement of control apparatus. Device has signal input device and directional valve which are both responsive to a control signal, and a fluid power cylinder assembly which is connectable to an input of the control apparatus to apply an amplified control signal thereto. The directional valve means controls fluid flow between first and second chambers on opposite sides of a piston of the power cylinder assembly so as to determine the direction of movement of the assembly in response to valve position. The signal input device has an indicator to indicate a particular control setting or datum for a control signal which can be felt by operator, which contrasts with prior art power assist device where feel of a particular setting location is lost.

Abstract: A portable hand-held hydraulically-operated cable cutter for severing electric and communication cables has a pair of cutter jaws, one fixed and one movable. The movable jaw is driven positively in both the closing and opening directions by a piston-cylinder assembly under the control of the lineman. The piston is fixed; the cylinder is movable. The movable cutter jaw is connected pivotally to the movable cylinder. The lineman holds the tool in one hand, using a fixed grip handle, and with the other hand controls operation of the movable cutter jaw by rotating a cylindrical control handle in one direction or the other. As a safety lock, the tool has an offset trigger which must be pressed to unlock the control handle before it can be rotated. When the control handle is released, it is automatically returned to its neutral position by a torsion spring, thereby instantly stopping any motion of the cutter jaws in either the opening or closing directions.

Abstract: A pressure fluid operated feed drive system for a movable member, and particularly for a slide of a machine tool, the system having a source of fluid pressure feeding a pair of interconnected piston and cylinder units connected between the member and a fixed support. The piston rod side areas of the pistons are arranged in effective opposition and valve means are provided to permit pressure fluid to be supplied selectively to the units to enable the member to be moved alternatively by a force derived from differing piston areas.

Abstract: A cushioning device, for cushioning the impact between a closed end portion of a cylindrical member of a hydraulic jack and an end portion of an inner member reciprocable within the cylindrical member, including a blind bore provided in one of the end portions, an elongated plunger attached to the other end portion for telescopic entrance into the blind bore as the end portions approach each other and an orifice for metering fluid forced from the blind bore by the progressive ingress of the plunger into the bore.