Abstract: In an hydraulic cylinder for vehicle braking elements, a clamping piston (1) moved in a housing (3) by hydraulic pressure acts relative to a brake lining carrier bearing a brake lining, e.g., in the form of a brake shoe which, during braking, is forced against the brake disk. To prevent the clamping piston (1) in rest position from being pushed back into its housing (3) by axial impact forces, the clamping piston (1) can be coupled at its interior to an hydraulic volume, which, in the neutral position of the clamping piston (1), acts as an hydraulic cushion and counteracts the impact forces.

Abstract: An improved blowout preventor actuator is provided for opening and closing a ram block within a blowout preventor body to control the flow of well fluid. The working or power piston within the actuator cylinder is provided with one or more axially extending cavities each for receiving a locking rod secured at one end to the cylinder head. To prevent inadvertent opening of the ram block, locking segments carried by the power piston repeatedly disengage one locking surface and re-engage an adjacent locking surface on the locking rods as the power piston and ram block secured thereto move to the ram closed position. To unlock the power piston from the locking rods, fluid pressure is applied to an unlocking piston which radially moves the locking segments out of engagement with the locking rods. The locking surfaces on the locking rods extend axially along a length which allows different ram blocks to be substituted for sealing with various diameter tubular members passing through the blowout preventors.

Abstract: A piston rod-free pressure cylinder, in which a force reducer (15) is connected by means of a lateral projection (14) to the working piston (13), has a brake mechanism (19), which acts with a brake lining (27) on the outside of the pressure cylinder (11). Action takes place in such a way that no transverse forces are exerted on the projection (14).

Abstract: A power cylinder of the type in which the piston may be locked to maintain the associated tool or clamp in a fixed position. A pair of guide rods extend in parallel spaced fashion through the bore of the cylinder from end to end of the cylinder and the piston includes a pair of spaced apertures passing the guide rods so that the piston may slide within the bore of the cylinder on the guide rods. The piston apertures are internally threaded and the guide rods include an externally threaded portion so that, following movement of the piston within the bore through a rapid advance portion of its stroke under the influence of pressure fluid, the internal threads in the piston apertures are brought into engagement with the externally threaded portions of the guide rods and the guide rods are thereafter rotated so as to threadably advance the piston to its final desired position in which the piston is lockingly held by the coacting threads.

Abstract: In a radial piston hydraulic motor of the "star-shaped" type the variation of the cylinder capacity is achieved by the fact that the motor crankshaft is provided with a mechanism which varies the eccentricity, this mechanism being powered by hydraulic actuators carried by the shaft and controlled by a circuit external to the frame of the motor, comprising a rotating coupling and stop valves, while stability of the cylinder capacity may be obtained by means of locking mechanisms carried on the shaft.

Abstract: A cylinder locking device comprises a thick cylindrical brake member whose inner diameter is slightly smaller than the outer diameter of a piston rod to be locked. The cylindrical brake member is disposed in a casing and fitted on the piston rod, and has a slit opening formed axially therein. Two receive rollers are disposed oppositely and rotatably on both margins of the slit opening. An actuator having a tapered portion is disposed in the casing. The locking of the piston rod is released when the tapered portion is forced in between the receive rollers to expand the cylindrical brake member. When the actuator is not in actuation, the piston rod is strongly gripped and locked by the elasticity in the diameter-decreasing direction of the cylindrical brake member.

Abstract: A new and improved ram locking apparatus for blowout preventer rams which allows the rams to be locked in the closed position and compensates for wear on the sealing elements of the rams. The device consists of a tubular cross containing a rod extension with a tapered end attached to the ram, a hydraulically reciprocal piston with a wedging surface to coact with the tapered end of the rod extensions and hydraulic fluid ports. The tapered end of the rod and the wedge surface of the piston have serrated surfaces to increase friction between the wedging surfaces and provide a self-locking engagement and thereby provide a small compact apparatus.

Abstract: The cylinder has a sealed back wall through which the rod passes. A piston assembly mounted on the rod between the back wall and a cylinder front end-piece contains a fluid-pressure-activated clamp. The front end-piece also has a clamp. By sequenced operation alternatively fixing the piston or the cylinder to the rod through the respective clamp, the relative travel of cylinder and rod can be extended to any desired length.

Abstract: An apparatus is proposed for releasably locking a bolt in the axial direction relative to a housing element surrounding it, in which the bolt has a circumferential groove tapering radially inward and a locking element inserted into this groove with a cross section adapted to that of the groove. The locking element protrudes radially beyond the cross section of the bolt and is in contact there on both sides with support surfaces, one of which is formed by the housing and the other of which is axially displacable under a compressive force load; at least one of these support surfaces is inclined, to provide a radially outwardly oriented reduction of the cross section formed between the support surfaces.

Abstract: A drawing apparatus in a press for holding the sheet metal part during the drawing and for the ejection thereof. Additionally, blocking devices are provided which prevent the ejection of the sheet metal draw part at the same time with the upward movement of the press ram. Each blocking device is thereby to be rendered selectively operable or inoperable. A continuous flow of the hydraulic liquid is to be precluded during the inoperative condition of the blocking device. The blocking device consists of a pressure cylinder, of a pressure piston which is displaceably movable on the piston rod displaceable by the draw cushion, and of a compression spring for the displacement of the pressure piston in the ejection direction. The pressure space formed above the pressure piston is selectively pressureless for the inoperative condition, respectively, adapted to be acted upon with controlled pressure for the operative condition of the blocking device.

Abstract: A piston and cylinder assembly for a vehicle hydraulic system has a retaining device comprising an insert acting between a piston and the cylinder bore in which it works, the insert having a releasable frictional engagement in the bore and acting as an abutment to hold the piston in its retracted position to maintain the effective length of the assembly at a predetermined value for installation, until the assembly is operated hydraulically. The assembly may be an actuator for a self-energizing disc brake, or a slave cylinder for a vehicle clutch system.

Abstract: Herein disclosed is a cylinder locking device for locking and stopping the piston rod of a hydraulic cylinder in a desired position. There are fitted rotatably in a housing, a pair of thick, semicylindrical halves which are formed by dividing a thick cylinder having eccentric outer and inner circumferential portions axially into two halves at the thickest and thinnest portions. The piston rod of the hydraulic cylinder is inserted slidably into the inner circumferential portions of the two semicylindrical halves. The piston rod is locked in the desired position by turning the two semicylindrical halves in the opposite directions through a pair of leaves which are attached to the two halves.

Abstract: A pneumatic cylinder having an elongated cylinder member, a reciprocally movable piston, transfer means for transferring reciprocal movement of the piston to a work piece and a brake mechanism associated and movable with the transfer means for creating a braking force between the transfer means and a portion of the cylinder member. The brake mechanism includes a first brake surface connected with the transfer means, a second brake surface formed by an exterior surface portion of the cylinder member and a brake actuation mechanism for selectively causing movement of the first and second brake surfaces into braking engagement with one another.

Abstract: The present device is intended to lock a member, such as a tool, substantially without play into a form-locked position which can be released only by a fluid pressure intentionally applied to the device. The construction is such that small clamping strokes or displacements can be performed and so that the form-locking or arresting force is maintained as long as desired and with safety. For this purpose a pull rod having, for example, a ring channel, is insertable into a socket type of receiver equipped with radially movable locking elements which cooperate with their own slanted surfaces with slanted surfaces of the pull rod and with slanted surfaces of a ring piston. Certain cooperating surfaces have a slant angle which is smaller than a self-locking angle. The release is possible only if the ring piston is exposed to a fluid under pressure.

Abstract: The apparatus comprise a generally tubular outer element, a generally cylindrical inner element disposed therewithin and sized relative thereto to provide a generally annular operating space therebetween. An intermediate element is disposed in said operating space and is dimensioned relative thereto to create interference fits with said outer and inner elements and prevent relative movement therebetween. Means are provided to introduce pressurized fluid to the respective element interfaces to expand the outer element within the elastic limit thereof to an extent sufficient to release the interference fits and enable relative outer-inner element movement. Re-locking of the outer and inner elements occurs automatically upon depressurization of the fluid and attendant return of the outer element to its unexpanded configuration. Actuating means to effect relative outer and inner element movement upon apparatus unlocking are also provided, and include means to pressurize the fluid.

Abstract: Locking apparatus for a piston and cylinder device includes a locking plunger connected to the piston and disposed between the piston and an end cap of the piston and cylinder device. The locking plunger includes a sleeve which carries a plurality of radially movable ball bearings. As the piston is moved toward an extreme position of the device, the ball bearings contact a spring loaded locking plug disposed in the head of the device, thereby moving the plug away from a first position. The piston and locking plunger continue to move the locking plug away from the first position until the balls are aligned with a circumferential groove or channel in the head. At this point the locking plug is moved to the first position under spring force, in turn moving the ball bearings radially outward into engagement with the channel or groove. The piston and piston rod of the device are thereby locked in position in the absence of fluid pressure.

Abstract: An activating apparatus or device, for example for a valve in a liquid conveying system operated by means of a vacuum. The activating apparatus comprises a normally latched or locked operating device which by means of a spring, or the like, is connected to a force accumulator. The force accumulator is moved by the influence of vacuum and thereby tightens the spring which, when a lock arm disengages from the operating device, is released so that the operating device is moved, and thereby opens the valve.

Abstract: Fluid actuator includes a lock mechanism for releasably locking the actuator against movement, and a lock release assembly including a lock piston engageable with a toggle linkage upon application of fluid pressure to the lock piston to release the lock mechanism. The toggle linkage is fixedly mounted on a rotatable cross shaft which may also be manually rotated by manual rotation of an external lock release lever attached to one end of the cross shaft for effecting manual release of the lock mechanism. The engaged or disengaged condition of the lock mechanism may be sensed electrically as by providing a target on the external lock release lever for movement therewith toward and away from a proximity switch.

Abstract: A disc brake includes a positioning device (40) which is pressure responsive to control the amount of retraction for a piston (22) within the disc brake. The positioning device includes a plug (44) movably and sealingly carried within the piston (22) and a pair of legs (48, 50). The plug (44) cooperates with the pair of legs (48, 50) to move the latter to a position in spaced relation to a caliper housing (12) when the pressure level within a pressure chamber (28) is above a predetermined value. A spring (52) cooperates with the plug (44) and the pair of legs (48, 50) to engage the latter with the caliper housing (12) when the fluid pressure within the pressure chamber (28) is below the predetermined value.

Abstract: An air brake safety and parking mechanism is provided in the form of an emergency braking system which operates automatically to set and latch the air brakes of a vehicle in a braking position whenever the air pressure of the service braking system of the vehicle drops below a predetermined threshold, and which may be set and released mechanically for parking purposes. The air brake safety mechanism of the invention includes an antifriction ball screw coupled to the air brake piston in the air brake chamber of the vehicle braking system, and extending along a selected axis into an air-tight housing which is mounted adjacent to the brake chamber. A ball nut is rotatably mounted in the housing in threaded relationship with the screw to permit linear movement of the screw in both directions along the selected axis so long as the nut is freely rotatable.

Abstract: An air brake safety and parking mechanism is provided in the form of an emergency braking system which operates automatically to set and latch the air brakes of a vehicle in a braking position whenever the air pressure of the service braking system of the vehicle drops below a pre-selected threshold, and which also can be set and released mechanically for parking purposes. The mechanism includes an aperatured latch through which an actuating rod for the air brakes of the vehicle extends and is freely slidable so long as the latch is in a first angular position, but which is engaged by the latch when the latch is in a second angular position to prevent movement of the rod in a direction which would release the brakes of the vehicle. A feature of the mechanism is that it can subsequently be released and then re-set so that the brake can be used for parking purposes, for example, for a trailer.

Abstract: A pneumatically driven device which in the exemplary form of the invention is an air tool driven by pistons. In the exemplary form there are two pistons having racks which drive the reciprocatable shoe through pinion gears. One piston drives in each direction. Each piston at the end opposite the driven end has an annular groove in it with a sealing ring with ports for communicating air to the area behind the ring for pushing it out against the inside surface of the cylinder. During a piston stroke at this end of the piston air is compressed to provide a cushioning and braking effect which improves the overall operation, and avoids excessive wear.