Abstract: In a stroke-limiter equipped integral power steering apparatus, a valve body of a spring-loaded-plunger-equipped limiter valve is configured to enable a position of the valve body relative to a housing to be adjusted in a longitudinal direction of the valve body via an intermediate sleeve.

Abstract: A hydraulic cylinder unit comprises a cylinder, a piston disposed within the cylinder, and piston rod connected to the piston. The piston rod is reciprocatingly received within the cylinder, and the piston rod being movable between a first position in which the piston rod is substantially disposed within the cylinder and a second position in which the piston rod is fully extended outside the cylinder. A first hydraulic port and a second hydraulic port hydraulically connecting the cylinder unit to a reservoir. Hydraulic fluid is received by the first hydraulic port and hydraulic fluid is discharged by the second port when the piston rod is actuated to move towards the first position. Hydraulic fluid is received by the second hydraulic port and hydraulic fluid is discharged by the first hydraulic port when the piston rod is actuated to move towards the second position.

Abstract: To improve a rack and pinion steering of the generic type to reduce noise development upon opening of the pressure-relief bore as well as in steady-state operation, the invention proposes that at least one filter element forming a flow resistance be inserted between the additional bore and the pressure connection.

Abstract: A method and an apparatus for controlling the function of all kinds of reciprocable power machines which are actuated by pneumatic, hydraulic of any other pressure fluid, irrespective if the machines are of rotary or axially operating type, in which the active power stroke is accomplished using full power of pressure fluid against a reciprocatable piston (2) in the active air pressure chamber (10, 12), and in which the reversing of the direction of operation is made by alternatingly supplying pressure fluid to the opposite air pressure chamber (12, 10) of the machine. A valve poppet (6) having several channels alternately places one of the pressure chambers (10, 12) of the reciprocatable fluid actuated machine (1, 2) under full pressure, builds up a certain counter pressure in a pressure chamber which is, at the actual moment, inactive, and evacuates the pressure from an inactive pressure chamber of the fluid actuated machine.

Abstract: A winch includes a cylinder containing a movable piston to which are respectively mounted a fixed and a movable pulley assembly around which a line to be pulled is entrained. The pulley assemblies are located within the working chamber and the line enters the cylinder through one end formed remote from the chamber and through a one way brake mounted to that remote end. The brake permits line to enter the cylinder as the working chamber is pressurized to move the piston and thereby the movable assembly towards the remote end. The one way brake prevents line from exiting the cylinder at this location. The line extends slidingly through the piston and may exit the cylinder at the opposite end thereof which is also equipped with a one way brake which prevents line from entering the cylinder but allows the line to exit the cylinder. End of stroke positions of the piston are sensed by means of Hall Effect Sensors to control pressurization and venting of the working chamber through a three way valve.

Abstract: A device for limiting a working stroke of a hydraulic cylinder has a working cylinder and a working piston comprising a hollow piston rod connected to its top portion. A pressure reservoir is connected to a first working chamber for constantly supplying a pressure medium thereto, and a pressure source is connected via an inlet line to a second working chamber for supplying a pressure medium thereto. A shut-off valve comprises a push piston and a return spring for holding the push piston in its closed position. A drag link is slidably connected inside the push piston and extends through the working piston into the interior of the hollow piston rod. One end of the drag link has a first abutment that comes into contact with the working piston before the working piston reaches its end position.

Abstract: Rack and pinion steering gear with hydraulic power assist that is reduced as the vehicle wheels approach their positive wheel stops so that hydraulic loads on the steering gear and linkage are reduced and the power steering pump is not forced to excessive operation in relief.

Abstract: The wedge-shaped operating member of a thread rolling attachment is reciprocated by a piston rod which extends into one end of a fluid pressure cylinder. A rotatable valve stem is mounted intermediate its ends in the opposite end of the cylinder for limited axial movement, and has thereon a valve seat normally closing a port which leads to a reversible valve that directs fluid under pressure selectively to opposite ends of the cylinder to shift the piston rod between retracted and advanced positions. The inner end of the stem is slidably connected to the piston rod so that when the latter reaches its advanced position it momentarily unseats the valve seat from the port to effect reversal of the valve and consequent return of the piston rod. The valve stem is rotatable to adjust the length of the stroke of the piston rod.

Abstract: A control device for a drive unit, preferably the drive unit of a power vehicle, is provided having a hydrostatic transmission where the adjusting device of the latter and the adjusting device of the internal combustion engine are controlled by means of a servo piston loaded by control pressure, whereby the internal combustion engine is prevented during reversing from being adjusted to an increased power output through a circuit before the adjusting device of the hydrostatic transmission has passed through the zero-stroke position, and where the circuit has two shut off valves whose outlets are connected with a line, which are connected to the spring-side pressure chamber of the operating cylinder of the internal combustion engine through a multiway valve.

Abstract: Hydraulic safety device for the mechanism for closing up the rolls of a rolling mill, comprising an hydraulic safety valve (20) which is accommodated directly inside the jack (1) for closing up the mill rolls and which automatically reduces the pressure of the fluid in the control chamber (12) as soon as the stroke of the body (11) of the jack reaches a predetermined limiting position.

Abstract: In an apparatus for forming leak-proof joints between tubes and a tube sheet by the internal application of hydraulic swaging pressure, the flow of relatively low pressure fluid from a pressure source to an intensifier is permitted or interrupted by a control valve. During a prefill period, a prefill valve causes the low pressure fluid to bypass the low pressure input side of the intensifier and flow directly to the high pressure side and then to a mandrel. Thereafter, the low pressure fluid is caused to enter the low pressure side of the intensifier to increase the pressure in the mandrel during a swaging period. A pressurization sensor, which is connected to the input and output sides of the prefill valve, contains a piston which is movable in response to the difference in the pressures at these two points to produce a termination signal which, after a delay, actuates the control signal at the end of the swaging period.

Abstract: In an apparatus for forming leak-proof joints between tubes and a tube sheet by the internal application of hydraulic swaging pressure, the flow of pressurized fluid from an adjustable pressure reduction valve is permitted or interrupted by a control valve. An actuator moves the control valve between its flow permitting and interrupting positions in response to a control signal. In the sensor, which is connected to the input and output sides of the control valve, a piston is movable in response to the difference in the input and output pressures to produce the control signal when a predetermined comparative pressure relationship exists.

Abstract: A method for adjustment and/or indication of a liquid or gaseous pressure, and advice for utilization of the method, including the use of a piston member (7, 7'), movably arranged in a surrounding housing (1), said member having two towards each other acting piston areas with different area, said piston areas being made subject to a pressure from the liquid or gaseous medium, a mechanical load also being supplied to the smaller piston area, whereby the piston surfaces only perform a common movement when the media pressure exceeds a predetermined limiting value, which limiting value comprises of resulting force for the force developed by the smaller piston area under influence of supplied media pressure and added mechanical force, said movement, when predetermined limiting value is exceeded, being arranged to influence a flow restricting valve member and/or indicate the pressure of supplied media.

Abstract: A power steering mechanism includes a control valve which acts both to control the flow of pressurized fluid to and from a pair of working chambers of the mechanism and as a pressure relief valve to limit the maximum pressure which may be communicated to the working chambers. The valve includes a stack of plane annular discs which are relatively rotatable and arranged coaxially with the control shaft of the steering mechanism. The discs are resiliently biased together and define valve ports and compartments which cooperate to control the flow of pressure fluid dependent upon the relative rotational positions of the discs. Rotation of the control shaft causes rotation of one of the discs relative to the others to correlate the ports and chambers so as to supply pressure fluid to one chamber and to vent fluid from the other chamber.

Abstract: A servo cylinder having a piston of the kind having spaced sections which move into an enlarged diameter low pressure bore portion of the cylinder is provided with a gasket assembly for each piston section in the form of an elastic sealing gasket having a resiliently flexible radial flange extending from an integral collar and supported by a rigid ring having a certain circumferential clearance from the collar to permit radial movement for misalignment compensation. The gasket may be formed in the cross-sectional shape of an L or of a T. Where an L-shape is used, a single support ring is provided and where a T-shape is used a support ring on each side of the radially extending flange which forms the leg of the T oriented 90.degree. would be used. The ring or rings are protective of the radial flange in either direction of movement of the respective piston.

Abstract: The hydraulic apparatus includes a valve which is closable to prevent fluid from flowing out of a cylinder chamber when the pressure of the fluid drops below a predetermined level, and a transmitter which opens the valve so as to keep the chamber pressure constant when a piston slidably received in the chamber moves due to heat-caused expansion of the fluid in the chamber. The apparatus is disclosed in the context of an aircraft spoiler control system.

Abstract: Linkages connected to the axles of a single or twin axle dump vehicle open a control valve mounted on the vehicle frame to divert hydraulic fluid from the lift cylinder to the hydraulic reservoir when the frame tilts laterally a preset amount relative to the axles.

Abstract: A pilot assembly for switching the fluid supply valve of a hydraulic pump is actuated by the pressurized hydraulic fluid which operates the hydraulic pump. The hydraulic pump includes a main cylinder, a main piston within the main cylinder, and a main valve for supplying pressurized hydraulic fluid to the rear end of the main cylinder for driving the piston forwardly. The pilot assembly includes a pilot cylinder and a pilot spool within the cylinder. A first hydraulic conduit connects one end of the pilot cylinder to the front end of the main cylinder, and a second hydraulic conduit connects the other end of the pilot cylinder to the main cylinder at a position spaced rearwardly from the front end of the main cylinder. When the main piston passes forwardly of the second hydraulic conduit, the pressurized hydraulic fluid in the main cylinder moves the pilot spool, and pressurized hydraulic fluid is allowed to flow to the main valve to switch the main valve.

Abstract: A pneumatic actuator in which a piston and a cylinder define an annular gap therebetween axially connecting two portions of the cylinder cavity otherwise separated by the piston. When compressed air is admitted to one of the cavity portions, an O-ring in an annular groove of the cylinder wall is expanded by the compressed air and seals the gap, and the piston is moved against the restraint of a strong compression spring. When the air backing the O-ring is vented, the air pressure in the cylinder drives the O-ring back into the groove, and air thereafter escapes quickly from the one portion of the cavity through the gap and into the other cavity portion which is open to the atmosphere. The resulting quick movement of the piston by the expanding compression spring is transmitted to a device outside the cylinder for operating the same.

Abstract: A gripping arrangement includes a gripping member operatively connected with a differential both-side acted piston movable in a pneumatic or hydraulic cylinder. The piston stroke includes a first step and a second step. The pressure acted upon the piston to move the same into the respective gripping position is partially counteracted at the first step so as to eliminate an undesirably fast movement of the gripping member during at least initial portion of the stroke. The remaining portion of the stroke the piston moves under full pressure exerted by the pressure medium supplied in the cylinder without any counteracting effect.

Abstract: An arrangement in the dropping of pressure in either chamber of a double acting booster steering servomotor is provided, such pressure drop starting at a predetermined point toward the end of travel of the servomotor piston in either direction. The invention is characterized by a respective bypass valve in each chamber, spring biased to closed position, and engageable by the piston, to be opened gradually. The piston force is exerted on the bypass valves through a respective spring so as to effect the gradual opening instead of the abrupt opening effected in the prior art. Opening of the bypass valves effects connections which shunt the servopump output to the system oil tank via a differential pressure valve as taught in Lang U.S. Pat. No. 3,878,763 to prevent strong mechanical stresses on the steering linkages at the ends of steering movement. Shunt control takes place through desirably small flow lines and bypass valves which heretofore have been found to produce undesirably abrupt operation.

Abstract: A feed pressure bypass valve means and actuator means primarily for a single acting servomotor, is provided having a unitary housing construction and an assembly of opposed springs wherein one spring biases a bypass valve to closed position and the other spring is compressed by the servometer piston to act in the opposite direction. The bypass valve is mounted externally of the servomotor as a separate and integral unit and has for its purposes to ensure maintaining a drop in feed pressure as the piston nears the end of its stroke. The provision of the spring compressed by the piston toward the end of the stroke ensures the opening and maintenance of opening of the bypass valve. There can be no instability of steering operation by virtue of the bypass valve closing and the striking of the servomotor cylinder wall by the piston is precluded.

Abstract: In an auxiliary power steering system, a steering linkage actuated limit valve assembly is maintained depressurized in its inactive state by one-way check valves blocking flow from the pressurized chambers of the steering servomotor and by by-pass valves which control the connection of the differential pressure operated valve to the vented chambers of the servomotor.

Abstract: A by-pass valve for servo-steering systems to turn off the working pressure in a cylinder chamber of a pressure medium cylinder, whose valve housing includes a valve connection adapted to be connected with the cylinder chamber, a valve connection adapted to be essentially pressure-relieved, and a valve seat for a check valve operatively connected between the two valve connections; the valve housing is thereby adjustable relative to the axis of a steering shaft for purposes of changing the position of its valve seat while the closure member of the check valve is thereby retained by springy means in its normal position closing-off the valve connections with respect to one another and is actuatable into its by-pass position connecting the valve connections with each other by way of a stem movable in unison with the closure member by way of a cam surface fixed for movement in unison with the steering shaft; the valve housing is thereby exclusively rotatable in relation to its valve housing axis but is immovably s

Abstract: A contact free device for limiting the relative movement of hydraulically actuated members in which the device includes a proximity switch actuated at each limit position of the members and which interrupts the supply of hydraulic actuating fluid to the members. The supply of fluid to the members is resumed when movement of the members relatively away from the respective limit position is initiated.

Abstract: An engine of the air-cooled, super-charged type which includes a stationary piston, a cylinder movable relative to the piston and operable in a first position to provide a compression chamber between adjoining ends of the cylinder and piston. In a second position, the compression chamber is opened to provide purging air flow from a compressor stage. A cooling air flow is provided about the surfaces of the cylinder and piston in both positions of the cylinder and during its travel between those positions.In a different embodiment of the engine, the internal combustion portion of the engine just described above is combined with a gas turbine stage. Upon firing of the fuel in the compression chamber and the subsequent opening of the chamber, the flow of hot gases is applied to provide a further rotative force to the turbine wheel.

Abstract: An apparatus for opening and closing the draft hood discharge opening and vent and fuel line of a fluid fuel-fired heating device such as a domestic water heater. The disclosed apparatus includes a diaphragm-type expansible chamber fluid motor assembly positioned in the burner fuel supply line. The motor assembly is mechanically linked to a damper assembly such that the supply of pressurized fuel acts to actuate the motor for opening the damper assembly prior to the motor assembly admitting fuel to the burner. Additionally, when the supply of fuel is terminated, the motor assembly does not close the damper assembly until after the motor assembly stops fuel to the burner.

Abstract: A hydraulic circuit for operator pre-selection in one exemplary embodiment of the extension of a lift truck upright which utilizes a fixed displacement hydraulic motor operating to adjust either a rotary switch or a potentiometer which is connected to a valve for interrupting the flow to the lift cylinder of the upright at the pre-selected height. The adjusted position of an operator's lift height selector is coordinated with the rotary switch or potentiometer or to effect the selected extension of the upright.

Abstract: The present apparatus controls the position of the brake flap or air brake of an aircraft. The air brake is operated by a power amplifier including a pressure cylinder and a piston. The piston is mechanically coupled to the brake flap or air brake in such a manner that the displacement of the brake flap is about proportional to the brake flap angle. The pressure in the cylinder is controlled in response to or as a function of the brake flap angle so that the flap is positioned at the angle required for the particular braking action, whereby the force caused by the dynamic or impact pressure is maintained in equilibrium with the force exerted by the pressure piston cylinder arrangement.

Abstract: A stroke limiting mechanism is connected with the movable member of a hydraulically operated machine to precisely position the movable member. The flow circuit for the stroke limiting mechanism is connected in such a manner that even if an equipment failure occurs, the movable member will be retained in a pressure-balanced condition, thus creating a fail-safe situation.

Abstract: A hydraulic valve assembly for operating a hydraulic elevator is simplified in its construction by positioning the check valve for the up level control in axial alignment with the bypass valve in the same valve housing mutually guided on a central valve stem. Pressure for actuating the bypass valve is controlled by a direct acting valve element structurally mounted on the valve element of the up leveling check valve.

Abstract: The invention relates to a hydraulic steering apparatus comprising a continuously operating pump, an operating motor for controlling the parts to be steered, a control device which is adjustable by the steering wheel and which, in its neutral position, connects the pump to a tank through a short-circuiting path. The control device has two operating positions in which the pump is connected to one side or the other of the operating motor and connects the other side of the operating motor to the tank. The control device has a control element connected to a steering wheel and a following element connected to a metering motor and these elements are relatively displaceable to a limited extent. Apparatus is provided to prevent the steering parts moved by the operating motor from stroking mechanical abutments.

Abstract: A hydraulic steering apparatus comprising a sump, a pair of motors controlling the vehicle parts to be steered, a steering wheel operated control device for controlling the motors, a continuously operable pump between the sump and control device, a pair of control conduits connected to the control device and meeting at a junction, a pair of stroke limiting control valves in the control conduits alternately actuable by the two motors, and an exhaust conduit from the junction to the sump. A short circuiting path shunting the pump, a pressure operated switching valve in the sort circuiting path, a pressure operated pilot valve for controlling the switching valve, a spur connection between the pilot valve and the exhaust conduit downstream from the spur connection to cause concomitant opening the pilot valve and the switching valve.

Abstract: The invention relates to a hydraulic steering apparatus comprising a continuously operating pump, an operating motor for controlling the parts to be steered, a control device which is adjustable by the steering wheel and which, in its neutral position, connects the pump to a tank through a short-circuiting path. The control device has two operating positions in which the pump is connected to one side or the other of the operating motor and connects the other side of the operating motor to the tank. The control device has a control element connected to a steering wheel and a following element connected to a metering motor and these elements are relatively displaceable to a limited extent. Apparatus is provided to prevent the steering parts moved by the operating motor from striking mechanical abutments.