Abstract: A spring-applied, air-released parking/emergency brake is combined with an air-actuated service brake through a friction clutch between the parking/emergency brake piston and a first nut member that is threaded onto a screw rod of the service piston. The screw rod and service piston are connected through another friction clutch. The screw rod is provided with a second nut member that is integral with a thrust rod to which the brake rigging is connected. A friction lock slack adjuster arrangement limits retraction of the thrust rod during brake release in accordance with the desired brake shoe clearance to be maintained. When the thrust rod movement is inhibited by the slack adjuster, the service piston clutch becomes disengaged to permit rotation of the screw rod during the release stroke of the service piston corresponding to overtravel due to shoe wear. Brake shoe clearance is thus maintained constant.

Abstract: A chuck actuator has a cylinder extending along a main axis and a piston axially displaceable in the cylinder, forming therein two compartments, and having an axially backwardly extending stem also centered on the axis and formed with two respective intake passages each having one end opening into the respective compartment and another end opening at a respective location on the stem. A connector rotatable about the axis on the stem is provided with respective fittings communicating with the locations. First and second axially spaced bearings prevent the connector from moving axially on the stem. Fluid is fed under pressure alternately to the fittings to pressurize and depressurize the respective compartments and thereby axially displace the piston in the cylinder. Normally the cylinder is connected to a chuck body and the piston to a chuck-actuating member for fluid actuation of the member.

Abstract: A control system for a plurality of hydraulic actuators which requires smaller number of control valves than that of actuators. In one embodiment, three control valves are arranged in parallel for controlling four hydraulic cylinders. The control valves are preferably solenoid-operated and one of control valves are used for supplying a pilot fluid pressure into a plurality of pilot-operated check valves disposed between the control valves and the hydraulic cylinders.

Abstract: A rotary fluid pressure actuator device includes a housing comprised of a pair of housing members interconnected together for relative movement therebetween. A vane rotor assembly is positioned in the housing and is rotationally reciprocated in response to the direction of flow of fluid to and from the interior of the housing members. The housing members are provided with internal stops which are adjustable with respect to each other to permit the rotational stroke of the vane rotor assembly to be variously adjusted. Rotary movement of the vane rotor assembly is transmitted directly or through a shaft to another device for actuation thereof.

Abstract: A low-pressure casing for a brake booster for automotive vehicles comprising two casing shells. A central ring flange is located at the inner surface of the end wall of each of the two casing shells. The portion of each end wall lying outside the ring flange is of truncated-cone-shaped construction and merges into a cylindrical circumferential casing section. At each of these merger points, a prop ring is inserted to bear against the inner surface of the associated one of the two casing shells.

Abstract: A tractor hydraulic control system of the kind comprising a power lift with a hydraulic actuator (12) and a main control valve (17) controlling the supply of fluid from a pump (19) to the actuator, the system including selector valve means (50) interconnected with the main control valve (17) and movable between a first position in which flow to and from the actuator (12) occurs via the selector valve means under the control of the main control valve and the associated system control mechanism (28) and a second position in which the actuator is hydraulically locked in a given position and an external services outlet (51) is placed in communication with the pump. Linkage means (60,61,62) operatively connects the selector valve means (50) and the system control mechanism (28) to condition the main control valve (17) to cause the pump (19) to supply fluid to the external service outlet (51) via the selector valve means on movement of the selector valve means to the second position.

Abstract: The pump or pumps for supplying fluid to the two ends of a double-acting cylinder include a direction control, such as a direction control valve, shiftable between extend and retract conditions. A drive mechanism for the direction control includes a rotary hydraulic motor and a driven rotary drive mechanism for shifting the direction control. Hydraulic fluid is supplied to the drive motor through parallel connected start and stop valves. The start valve is opened in response to the movements of the hydraulic cylinder toward a stroke limit. The stop valve is operated in response to the shifting of the direction control, so that the motor is operated intermittently to reverse the direction control when the cylinder reaches the limit of an extend or retract stroke. The stop valve is controlled by the drive mechanism in timed relation with the shifting of the direction control. The start valve may be closed by that drive mechanism in timed relation with the opening of the stop valve.

Abstract: Fluid control systems frequently eliminate use of fluid operated jack protecting relief valves because additional visibility blocking and damage prone conduits are required to connect the relief valves to the reservoir. A fluid operated system having a controlling valve, a selecting valve, a fluid operated jack, a relief valve, a reservoir and a bypass valve is provided to controllably connect the relief valve to other portions of the system in response to the position of controlling valve and selecting valve. Therefore, no additional conduits are required to connect the relief valve to the reservoir and thus the problems of reduced visibility, premature conduit leakage and conduit damage are eliminated. The fluid control system is particularly suited for use in a work vehicle such as a lift truck having a lift mast.

Abstract: The present invention relates to a hoisting gear for patient-lifting device whereby a plunger device (6) is displaceably mounted in a hydraulic cylinder (4), is supporting patient-carrier means (3) such as a seat or a patient-carrying plate and is raisable my means of a pump device (8) provided to move hydraulic oil between two hydraulic-cylinder chambers (9a, 9b) separated by the plunger device, and whereby a lowering device (39) is provided to permit lowering of the plunger device by producing a counter flow of hydraulic oil between the hydraulic-cylinder chambers.

Abstract: A fluid motor comprising a piston and cylinder combination includes mechanism for locking an output shaft which is helically displaceable along its longitudinal axis upon actuation of the piston. The locking mechanism includes a locking element driven by a fluid operated motor for displacement in a direction transverse to and spaced from the longitudinal axis of the shaft, and a notch in the shaft for receiving the locking element, the notch and locking element have mating surfaces which are inclined with respect to the longitudinal axis of the shaft and transverse to the shaft's helical path of travel. The locking element motor comprises the piston and cylinder chamber defined within a body upon which there is also mounted a cam guide for guiding a cam member which is secured to the shaft on the opposite side of the notch. The locking element is secured to and extends transversely of the locking piston into an opening within the body adjacent the shaft.

Abstract: A fluid operated device comprising an elongated housing defining an elongated interior cylinder and an elongated slot formed along one side of the housing and open to the cylinder. A piston is longitudinally, slidably mounted in the cylinder and forms a first chamber in the cylinder between one end of the housing and one end of the piston and a second chamber between the other end of the housing and the other end of the piston. Fluid seals are provided around each end of the piston. In addition, an elongated band constructed of a magnetic material is secured within the cylinder and is of sufficient width so that the band covers the housing slot. A pair of elongated flexible magnets are secured to the housing along the slot to magnetically attract the band against the housing and thus sealingly close the housing slot along the cylinder chambers.

Abstract: A double-acting hydraulic jack, comprising a hollow piston reciprocable in a surrounding cylinder, includes a tubular shaft extending axially inside and carrying a nut of the circulating-ball type which coacts with a screw coaxially disposed in that shaft. The screw is rigid with the piston whereby an axial displacement of the latter is translated into a rotation of the shaft; a toothed wheel on the shaft, engaged by a spring-loaded detent, acts as a one-way brake enabling such rotation only in one direction and blocking it in the opposite direction unless the detent is withdrawn by a hydraulic servomotor which is pressurized concurrently with the admission of fluid to the cylinder tending to displace the piston in the normally blocked direction.

Abstract: A piston pump assembly comprising a housing, a piston member mounted for axial movement in a bore of the said housing forming a piston chamber, and arranged coaxially relative to a drive shaft, said piston comprising a thin-walled member of generally cup shaped configuration, cam means associated with said drive shaft disposed in the recess of said cup shaped piston and cam follower means associated with said piston operatively connected to said cam means whereby rotation of said shaft effects through said cam and cam follower means axial back and forth movement of said piston in said piston chamber.

Abstract: The body of the braking valve includes a front chamber, an intermediate chamber and a rear chamber which surround a blocking component and a governing piston. The diameter of the bore, in which slides the governing piston at the rear of the chamber, is equal to the diameter of the line along which the truncated conical bearing surface of the blocking component comes into contact with a seat situated between the front and intermediate chambers. The pressure in the intermediate chamber is connected to an outlet of a distributor which has no effect on the balance position on the blocking component.

Abstract: A cylinder stop or collar includes a pair of identical mating cam members. Each cam member has a body and a pair of ramps which define cam surfaces. The ramps have slots for receiving attaching means such as bolts. Each cam member also has a slot so that it may be slid on and off the rod of a cylinder without disconnecting the cylinder.

Abstract: A blow-molded bellows of a thermoplastic elastomeric material has a generally cylindrical hollow accordion-type convolution section and ends integral therewith. The ends has axial protrusions extending outwardly from the central areas of respective ends. Each protrusion is connected to an adjacent convolution by an integral shoulder which has inwardly concave portions and outwardly convex portions. The concave portions are adjacent to the parting line, whereas the convex portions are remote from the parting line. By this feature of the bellows, the outermost convolutions of the accordion-type convolution section of the bellows can be molded into circumferentially substantially uniform wall thickness to assure improved operability and heat-resistant property of the bellows.

Abstract: A Bourdon tube apparatus is provided for monitoring the pressure of a fluid pressure source. The output of the Bourdon tube is translated into a curvilinear motion which is transmitted to a linearly movable actuator valve or indicator. To enhance the force output linear response or linear output of the Bourdon tube actuator, an abutment block is provided which contacts one or more turns of the Bourdon tube adjacent its closed end to prevent expansion movement of the Bourdon tube in a direction opposite to the desired linear output movement. The Bourdon tube is mounted for calibrational purposes by having its open end connected by a flexible pipe to a support post which is rotationally mounted for movement about its longitudinal axis and defines a fluid conduit connection between the pressure source being monitored and the open end of the Bourdon tube.

Abstract: A concrete pump comprises a pair of separate pump assemblies each having a cylinder, a piston subdividing same into a piston-side front compartment and a rod-side rear compartment, and a piston rod connected to the respective piston and extending out of the respective cylinder through the respective rod-side rear compartment. The pump also has a liquid supply having a high-pressure side and a low-pressure side for supplying liquid under high pressure at the high-pressure side and for taking in liquid at the low-pressure side.

Abstract: A hydraulic excavator is disclosed which includes two sets of manual control valves for selectively placing a pair of variable displacement pumps in and out of communication with hydraulically driven components such as propelling motors, arm cylinders and boom cylinders. In order to minimize the per-cycle displacement of the pumps when same are discommunicated from all the driven components, a sensing valve is provided which is pilot operated from the sets of manual control valves. When all the manual control valves are in neutral, the sensing valve directs pressurized fluid from a charging pump to a pump-displacement adjustment mechanism thereby causing same to reduce the per-cycle displacement of the pumps to a minimum.

Abstract: A fluid pressure servomotor for automotive vehicle brakes embodying a housing provided by assembling two shells, a pressure responsive power wall in the housing, a valve mechanism associated with the power wall and being movable relative thereto to control the differential pressure across the power wall, an actuating member connecting the pedal for manually moving the valve mechanism, and an output member for connecting the power wall to a brake master piston. The shells are assembled by being locked together and can be disassembled and reassembled due to the provision of a mechanism for resiliently restoring a yieldable portion in a locking structure so that the shells are reassembled by a uniting axial movement and a subsequent rotative movement to lock the shells with each other in position against such resiliency.