Abstract: A lock assembly of a blowout preventer is provided. The blowout preventer includes a ram assembly slidably positionable in the channel and engageable with a tubular. The ram assembly includes a ram block, a ram cylinder, and a ram shaft. The lock assembly includes a lock cylinder and a lock piston. The lock cylinder is operatively connectable to the ram cylinder. The ram shaft has an end slidably extendable into a lock cavity of the lock cylinder. The lock piston is slidably positionable in the lock cylinder and separates the lock cavity into a lock and a closing chamber. The lock piston has a ram surface engageable with the end when the lock piston is in a locked position, and a ram hole therethrough to receive the end when the lock piston is in an unlocked position whereby the ram block is selectively lockable about the tubular.

Abstract: An asymmetrical ram button is provided. In one embodiment, a system includes a blowout preventer including such a button. Particularly, the blowout preventer may include an actuation assembly having the asymmetric ram button attached to a connecting rod coupled to a piston. The asymmetric body of the button can engage an internal shoulder of the ram such that a retraction force on the actuation assembly causes the asymmetrical ram button to load against the internal shoulder. Additional systems, devices, and methods are also disclosed.

Abstract: An actuator includes a cylinder and a piston disposed in the cylinder. The piston has a head and a rod. The actuator further includes a collapsible locking member disposed in the head of the piston, and a gas-filled capsule disposed in the cylinder. The gas-filled capsule is in an expanded position when fluid in the cylinder is below a threshold pressure, and the gas-filled capsule is in a collapsed position when fluid in the cylinder is above the threshold pressure. The actuator also includes a lock piston operably connected to the gas-filled capsule. The lock piston engages the collapsible locking member and biases the collapsible locking member radially outward to a locked position when the gas-filled capsule is in the expanded position.

Abstract: An apparatus comprising a downhole tool having a body defining an outer surface, a plurality of standoffs distributed about the outer surface, and a hydraulic circuit operatively coupled to the standoffs. The hydraulic circuit includes a plurality of hydraulically actuated pistons, each of which is operatively coupled to a respective one of the standoffs to extend and retract the respective standoff. The pistons are hydraulically coupled and sized to extend or retract the respective standoffs at substantially the same rate in response to a hydraulic control signal.

Abstract: A vehicle has an internal combustion engine, an automatic transmission with an electrohydraulic transmission control unit, a transmission oil pump driven by the engine, and an electronic engine start and stop system. The start and stop systems switches off the internal combustion engine in operating phases, in which the vehicle is temporarily stopped, if predefined operating parameters are present, and starts the internal combustion engine if a restart signal is present. A purely mechanical pressure accumulator device provides stored hydraulic pressure to the electrohydraulic transmission control unit in a time period following the starting of the internal combustion engine, in which time period, the transmission oil pump is still building-up pressure.

Abstract: A valve for use with a turbocharger is disclosed. The valve may have a valve element movable to selectively direct a flow of fluid. They valve may also have a control portion connected to move the valve element, and a cooling portion configured to receive a pressurized cooling medium from the turbocharger.

Abstract: The invention relates to a device for locking an axially movable component (2) of a hydraulic system, wherein the axially movable component (2) can be detachably fixed in a positively locking manner in at least one axial position by means of a detent mechanism (4) with at least one detent body (5), and with a release device (6) for releasing the respective detent body (5) from the axially movable component (2), wherein the detent mechanism (4) can be latched and released by means of a clamping piston (7) and using a force store (8), and wherein the clamping piston (7) can be moved in a working chamber (27) which can be charged with a clamping pressure, which device is characterized in that the clamping piston (7) can be adjusted at least into one switching position by a switching device (9), in that the clamping piston (7) can be acted on with the clamping pressure by means of the switching device (9) and, in said switching position, can be moved out of the latching position thereof by the force store (8) in

Abstract: A locking piston assembly (100) is provided according to the invention. The locking piston assembly (100) includes a piston chamber (107), a piston rod (106) configured to be substantially extended from and substantially retracted into the piston chamber (107), and a piston head (108) coupled to the piston rod (106) and configured to move reciprocally in the piston chamber (107). The locking piston assembly (100) further includes at least one lock (120) configured to mechanically lock the piston head (108) and the piston rod (106) in at least a substantially fully extended position. The lock (120) is configured to unlock the piston head (108) and the piston rod (106) in a presence of a pressurized fluid provided to retract the piston rod ( 106). The pressurized fluid is introduced into the piston chamber (107) and the piston rod (106) is retracted only after the lock (120) is unlocked.

Abstract: A piston assembly (10) comprises a fluid actuated piston (14) mounted within a cylinder (12), and a fluid actuated locking mechanism (16) mounted within the cylinder (12) for selectively locking the piston (14) relative to the cylinder (12). In one arrangement, the piston (14) and locking mechanism (16) are actuated by fluid supplied via a common fluid port (48).

Abstract: A vane type hydraulic rotary actuator incorporates a fail-safe brake for preventing movement of the device's rotor relative to a housing in which the rotor is journaled. The brake has a spring-biased piston that is forced to a locked condition whenever applied hydraulic operating pressure acting on the vane falls below a predefined limit. The rotary actuator also incorporates an improved sealing arrangement that prevents egress of hydraulic fluid from a high pressure chamber on one side of the vane to a low pressure chamber on the opposite side of the vane.

Abstract: A plunger-cylinder assembly for a press including a plunger which is accommodated at least in part in a cylinder while separating the interior of the cylinder into two partial chambers along the cylinder axis. A relieving device which counteracts an increase in pressure of a fluid accommodated in the first partial chamber is disposed in at least one first partial chamber the increase in pressure being caused by a movement of the plunger along the cylinder axis in the direction of the first partial chamber. A hydraulic press encompassing such a plunger-cylinder assembly is also described.

Abstract: A system for mounting or/demounting a cylinder unit (1) in a vehicle. A piston rod (5) provided with a piston (4) arranged in the bore (6) of the cylinder unit (1) which piston (4) and piston rod (5) are displaceably arranged in the axial direction of the bore (6) of the cylinder unit. The bore (6) has an opening (13) provided for an end portion of the piston rod (5) to protrude out from the bore, and the piston (4) separates the cylinder unit into a first chamber (7) and a second chamber (8) . At least a first passage (9) is provided for communication of fluid into or out of the first chamber (7) . In an initial operating position of the cylinder unit, the piston (4) and the piston rod (5) is positioned with the end portion of the piston (5) protruding out from the mouth of the bore (6).

Abstract: A fluid pressure cylinder can apply a fastening force to an axially movable reciprocating rod. A reciprocating rod 13 is mounted in a case main body 10 so as to be reciprocable in a forward direction and a backward direction, and two lock units 16a and 16b are incorporated in the case main body 10, and the lock units 16a and 16b include: lock sleeves 18a and 18b mounted axially movably and having taper surfaces 22a and 22b; and retainers 19a and 19b holding steel balls 21a and 21b that are fitted in the reciprocating rod 13 axially movably and engaged with the taper surfaces. A fastening cylinder 41 that contains a fastening rod so as to be reciprocable in a fastening direction and a fastening release direction is attached to the case main body 10, a fastening surface 44 contacting with the lock sleeves 18a and 18b being formed in the fastening rod, and the reciprocating rod 13 is fastened by the two lock units 16a and 16b.

Abstract: The present invention concerns a parking lock for combination with a service brake actuator for a vehicle, preferably a heavy road vehicle. The service brake actuator comprises a fluid actuated piston having a piston rod. The parking lock surrounds the piston rod of the service brake. The parking comprises a pneumatically or hydraulically actuated locking The parking lock has a locking mechanism and an actuating mechanism. The piston rod is free to move in axial, radial and angular directions in relation to the locking mechanism.

Abstract: A region including an engaging hole is given surface treatment such as partial quench hardening by induction hardening for improving surface hardness of the region. The partial quench hardening by induction hardening provides the region with satisfactory mechanical strength or surface hardness enough for resisting deformation of the engaging hole and wear-out of an edge of opening of the engaging hole caused by putting in and out of the lock pin.

Abstract: The invention relates to a device for displacing and locking movable switch parts (1), comprising a hydraulic piston, which is formed by a rod (6) and cooperates, via coupling or locking members (8), with an axially displaceable sleeve (5) intended to receive the radially displaceable coupling or locking members (8), The displaceable sleeve (5) is coupled with the movable switch parts (1) and an externally arranged tube (4), at least partly overlapping the sleeve (5) and the rod (6). A hydraulic duct (11) is connected to the externally arranged tube (4), on a front face of the sleeve (5), facing away from the coupling site for the movable switch parts (1).

Abstract: A first piston (22) of a first locking cylinder (20) descends when a pressure of compressed air in an actuation chamber (23) has exceeded a pressure for locking commencement (P1) and ascends by a first spring (24) when the pressure of the compressed air has decreased to a pressure for releasing commencement (P2). A second advancing and retreating cylinder (32) comprises an inlet chamber (41) and an outlet chamber (45) formed below and above a second piston (35), respectively, and a second spring (46). The actuation chamber (23) communicates with the outside air through the outlet chamber (45). A restricting passage (37) is provided in a route between the actuation chamber (23) and the outside air. The actuation chamber (23) communicates with one of the inlet chamber (41) and the outlet chamber (45) through a communication hole (62).

Abstract: A first piston (22) of a first locking cylinder (20) descends when a pressure of compressed air in an actuation chamber (23) has exceeded a pressure for locking commencement (P1) and ascends by a first spring (24) when the pressure of the compressed air has decreased to a pressure for releasing commencement (P2). A second advancing and retreating cylinder (32) comprises an inlet chamber (41) and an outlet chamber (45) formed below and above a second piston (35), respectively, and a second spring (46). The actuation chamber (23) communicates with the outside air through the outlet chamber (45). A restricting passage (37) is provided in a route between the actuation chamber (23) and the outside air. The actuation chamber (23) communicates with one of the inlet chamber (41) and the outlet chamber (45) through a communication hole (62).

Abstract: The double-acting hydraulic actuator (1) with an axial locking device comprises a cylinder chamber defined by two coaxial cylindrical walls (26, 27) of different diameters that are interconnected by a frustoconical wall (25). A guide piston (7) sliding in the smaller-diameter cylindrical wall (26) is fixed to the end of an actuator rod (9). The actuator rod (9) has an annular protuberance (33) of diameter equal to the diameter of the cylindrical wall (26). An annular stepped piston (40) providing sealing between the two cylinder chambers is slidably mounted on the middle portion (34) of the actuator rod to slide between the piston (7) and the annular protuberance (33). When the actuator is extended, the narrowed end (44) of the annular piston (40) bears against conical surfaces (46) of two half-rings (41a, 41b) and urges them outwards.

Abstract: A cylinder apparatus comprises a cylinder tube which is connected between a first cover member and a second cover member each having a cylindrical configuration, an axially displaceable piston which inscribes the cylinder tube, a piston rod which is connected to the piston, an intermediate member which is connected between the cylinder tube and the second cover member, an axially movable member which inscribes the intermediate member, a first spring member which is connected between the second cover member and the movable member, and a piston pin mechanism which is inserted into a recess of the piston rod in a direction perpendicular to the axis.

Abstract: A hydrostatic axial piston machine has a swashplate, a cylinder block, a cylinder block bearing system, a brake to arrest the cylinder block, and a compensation device to relieve the cylinder block bearing system from axial engine forces. The compensation device is integrated into the brake. The brake has a brake piston loaded in the closing direction by a spring and has a relieving surface which acts in the opening direction and can be pressured by hydraulic pressure and is active opposite to the axial engine forces. The cylinder block bearing system has two helical roller bearings in an O-arrangement and the brake piston is an annular piston located axially between the helical roller bearings. A retaining ring of the spring is supported against the inner ring of a helical roller bearing provided to absorb axial engine forces.

Abstract: A valve for controlling flow of cryogenic liquid propellant in a rocket engine comprises a double acting piston-cylinder unit having a first position in which the valve is closed and a second position in which the valve is open, a locking device being engageable with the double acting piston-cylinder unit to lock the unit in the closed position of the valve is closed while being free from the valve in its open position. The locking device has a control piston connected to a locking member to selectively lock and unlock the piston-cylinder unit against the force of a spring acting to lock the piston-cylinder unit, and a control chamber capable of receiving a pressure medium to move the piston and to unlock the piston-cylinder unit. A two-way control valve controls flow of the pressure to the control chamber and to valve closing and opening operation chambers of the piston-cylinder unit.

Abstract: An improved combustion powered tool for driving fasteners into a workpiece includes a main housing enclosing a cylinder body and an adjacent combustion chamber. The tool includes a workpiece-contacting nosepiece attached to the housing at the end opposite the combustion chamber and holds fasteners to be driven into the workpiece. A reciprocally disposed piston is mounted within the cylinder body, and is attached to an elongate driver blade, the driver blade being used to impact the fasteners and drive them into the workpiece. At the upper end of the cylinder body is disposed a compressible piston retaining device. The retaining device is of sufficient strength to accommodate the weight of the piston and to retard the upward velocity of a returning piston, but is overcome when the tool is fired.

Abstract: A control system has an HHC actuator having a basal portion and a movable portion. A load acting on the control system is detected by a semiconductor gauge. The load detected by the semiconductor gauge is compared with a threshold value in a computer. If the detected load is larger than the threshold load, the movable portion is fixed to the basal portion by a fixing mechanism. By detecting the sign of stall of blades, the HHC actuator is fixed in a neutral position, allowing safe flight. A fixing switch is provided for allowing the fixing mechanism to operate regardless of the result of the comparison with the computer.

Abstract: A coupling mechanism, comprising a relatively fixed member and a relatively moveable member, is configured such that said moveable member may be securely connected in a locked position with said relatively fixed member by remote control of a shiftable member mounted on said relatively moveable member, and which shiftable member may be moved by remote control, into a position allowing disconnection, when desired.

Abstract: A machine tool is suggested, which has a headstock (111) and at least one tool changer (120). The tool changer (120) moves production tools (116) between a magazine position and a working position, at least one fluid power drive cylinder (1) being associated with it as a drive unit (123). On the drive cylinder (1) a locking device (52) is provided, which when a working pressure of the drive piston (6) drops below a predetermined value produces a mechanical locking action of the drive cylinder piston in relation to the housing. To release the mechanical locking, a setting force due to the working pressure must be overcome.

Abstract: A pressure-discharged type retaining system is designed so that supplying and discharging of a high-pressure fluid permits the relative movement of an annular outer member and an inner member inserted and fitted therein in either or both of axial and circumferential directions and retains the outer and inner members stationary. In the prior art, to insure the smoothness and safety of the operation, a high processing accuracy, a measuring accuracy and the like have been required in the production of such a system, resulting in an increased cost. According to the present invention, either one of the adjacent inner and outer members is formed, on its outer or inner surface, with a metal layer which has a predetermined difference in hardness from that of the other member, thereby solving the above subject.

Abstract: An actuator lock is provided to prevent movement of an actuator until the actuator lock is released. A first member of the lock is movable in response to fluid pressure within a chamber to move from a locked position to an unlocked position allowing the actuator to move. The first member is held at the unlock position by a latching member so that the lock cannot return to the locked position. During testing of the actuator, a test member is operable to reversibly move the first member from the locked position to an unlocked and unlatched position.

Abstract: A rolling mill in which an upper housing is guided upward and downward along columns, a fluid chamber is formed between the upper end section of each column and a column insertion hole of the upper housing; a fixed piston fixedly mounted on the column is fitted in the fluid chamber; a roll gap rapid widening piston is fixedly installed on the upper end of the column, and on this piston is vertically movably fitted a hydraulic cylinder; the hydraulic cylinder is fixedly mounted in the upper housing; pressure fluid is constantly supplied to an upper fluid chamber on the piston; a fluid chamber is provided in the column insertion hole of the upper housing, and a column clamping sleeve is fitted therein; and the pressure fluid is fed into, and discharged out of, the fluid chamber to move the upper housing upward and downward.

Abstract: Disclosed is a braking apparatus for a rod-less cylinder. A transfer member (3) arranged outside a cylinder body (1) is coupled to a piston (2) disposed movably within the cylinder body (1), and moves together with the piston (2). A brake rail (8) is arranged on the outer side surface of the cylinder body (1), extending in parallel to the moving direction of the piston (2). A braking member (16) faces the brake rail (8) in such a manner as to be engageable therewith, and disengageable therefrom, and is moved to a contact position where it engages the brake rail (8), and a release position where it disengages from the brake rail (8) by an operation member (17), to accomplish the braking and unbraking of the transfer member (3).

Abstract: This invention relates to an assembly of a hydraulic motor and a combined device for immobilization, comprising: a reaction cam; a cylinder-block mounted to rotate with respect to the reaction cam; a first immobilization member fast with the cylinder-block; a second immobilization member fast with the reaction cam and capable of being disposed in a first position, in which the first and second immobilization means are fast with one another, and a second position, in which these first and second immobilization members do not cooperate for their mutual immobilization. The device for adjusting the relative position of the first and second immobilization members comprising a jack comprising a chamber.

Abstract: A hydraulic jack particularly intended for use in automobile lifts includes a safety stop mechanism including a fixed toothed rod and a piston-supported pawl mechanism which includes one or more stop members. Each of the stop members can be retracted, to allow the jack to collapse, by applying hydraulic pressure to the chamber above the piston.

Abstract: A brake actuator for a railway brake which provides both service and parking braking comprises a cylinder having an operating cavity. A piston assembly extends into the operating cavity and has a stepped bore including second and smaller third cavities. A first hydraulic supply admits pressurized hydraulic fluid into the operating cavity to extend the piston assembly to apply the service brake. A spring applies a retracting force on the piston smaller than the hydraulic force. A hollow parking brake piston carried in the second cavity extends to react against the cylinder and extend the piston assembly in response to the supply of pressurized fluid to the second cavity from a second hydraulic supply to apply the parking brake. A mechanical lock, comprising a one-way clutch utilizing ramps and rollers, locks the piston extended from the piston assembly cylinder to maintain the parking brake applied upon removal of the second hydraulic supply force.

Abstract: A piston sealing arrangement for pressure-fluid-operated systems is disposed in an annular recess of a piston (5) or an associated housing (4) and is composed of a sealing ring element (1A, 1B) as well as an elastic element (2, 3) acting on one side in opposition to the direction of the pressure force (A). Herein the elastic element is dimensioned such that the sealing ring element (1) moves against its elastic element (2, 3) at a pressure smaller than the force against which the piston (6) is moving and by which it is kept on its stop, a pressure-fluid film being formed as a result which safeguards a uniform initial movement of the piston to a largest possible degree.

Abstract: A hydraulic cylinder that locks into position has a housing (1) with at least one pressure connection (7) and a piston (3) and rod (6) that travel tight in an out of the housing. The locking mechanism comprises a piston (11) that rests against a spring (35) and a barrier mechanism (23) with a cage of balls (25) that roll radially into a locking position in a locking groove (26) and back into an unlocking position in an unlocking groove (22). The primary piston communicates with a hollow space (18) and acts on a primary participating surface (19) and the locking piston communicates with an unlocking space (13) and acts on an unlocking surface (14) by way of the pressure connection. There is a variable choke (17), which disengages after a while, beween the pressure connection and the primary space (18) in the primary piston (3).

Abstract: A sequential remote control plug release system allows actuation of plug release plungers and manifold valves associated with a cementing plug container only in a predetermined sequence. With regard to a plug container having two plugs, and thus two plug release plungers, and three manifold valves, the middle and upper manifold valves and the upper plug release plunger can be opened and retracted only in a predetermined sequence. This is implemented through interconnected actuation valves and sequencing valves contained in a housing which can be located remotely from the plug container. An improvement in plug release plungers is also disclosed.

Abstract: An interlock device for a pressure-medium actuator, having a locking slide received in a housing and with an adjusting slide arranged transversely relative to the said locking slide and coupled kinematically to the locking slide, and, in an interlock position of a locking element connected to the locking slide, at least one positive engagement member provided on the locking element is in engagement with a corresponding mating engagement member on the actuator.

Abstract: An actuator including a cylinder having a longitudinal bore, a piston slidably and sealingly inserted into the cylinder, and a lock mechanism for temporarily locking the piston, the cylinder including a cylinder body having the longitudinal bore, a cylinder formed at a front end of the cylinder body and accommodating the lock mechanism, and a front wall connected to the cylinder head at a position opposite to the front end of the cylinder body and having a hole formed therein, the piston including a piston head slidably and sealingly inserted into the cylinder bore, the piston rod projecting from the piston head and slidably insertable into the hole of the front wall, a key groove formed on the piston rod at a position near the piston head, and a longitudinal hole formed within the piston head and the piston rod, wherein the diameter of the piston rod decreases from a backward position adjacent to the key groove to a forward position spaced from the piston head.

Abstract: An improved self-locking piston for use in ram blowout preventers has a hollow cylindrical outer piston which slidably contains an inner locking piston. The inner locking piston has a tapered, frusto-conically shaped front section with a plurality of circumferentially spaced apart, sloping flats formed therein. Apertures provided through the outer wall surface of the main outer piston contain radially slidable driver segments each having a sloping surface complementary to the sloping surface of the flats on the inner piston. Forward motion of the inner piston relative to the outer piston forces the driver segments radially outwards in the apertures. A plurality of locking segments, one each positioned in a groove rearward of and communicating with a separate one of each of the apertures is provided. Each locking segment has a sloping lower front surface adapted to sliding engagement by the sloping upper rear surface of a driver segment.

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: A hydraulic actuator comprising a cylinder formed with an axial cylinder chamber, a main piston provided in the cylinder chamber and dividing the chamber into a first chamber and a second chamber and further formed with a locking chamber, an annular locking groove formed in the cylinder, a locking member cooperating with the annular locking groove to lock the main piston in a predetermined position, the locking member movable between an unlocking position and a locking position, a locking-unlocking piston for moving the locking member into the locking and unlocking positions, and a pressure introducing passageway for selecting the first or second chamber that is higher in pressure and introducing the higher pressure in the selected chamber into the locking chamber of the main piston. The locking-unlocking piston is moved by the pressure introduced by the pressure introducing passageway to move the locking member into the locking and unlocking positions.

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 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 piston-cylinder device powered by a pressurized fluid and having a mechanical locking means for the piston. The locking means is alternatively actuated into and out of locking position by the pressurized fluid.

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: A hydraulic actuator including an actuator cylinder and a ram slidable therein from a retracted position to an extended position. This ram has an axially extending chamber positioned in an end section and a number of ball passageways extend between this chamber and the outer surface of the ram. A locking ball is positioned in each passageway. A ring is slidably mounted on the ram and is positioned at its forwardmost point of travel to hold the balls so that they do not project from the passageways. A spring biases the ring towards its forwardmost position. A ball moving spool is slidably mounted in the chamber and has an annular ball receiving recess. A stop is located in an end section of the cylinder for preventing further forward movement of the ring and this stop causes the ring to slide rearwardly relative to the ram upon further extension of the latter.

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: The invention is directed to a penumatic or hydraulic drive for opening and closing of doors, in which the linear motion of a double-acting piston 5 driven by a pressure medium is converted into a rotary motion of a spindle 2 through a piston rod 6 and a helical gear box 3. Herein a blocking lever 10 supported in a stationary manner is provided, which in the closed position of the door engages under the action of a spring 18 at a part 11 connected with a piston 5, wherein said blocking lever secures the piston in its end position and is held in its open position counter to the force of an additional spring 15 by a power cylinder 14 acted upon by the pressure means.

Abstract: The invention relates to a piston and cylinder unit whose piston rod is provided with a rack extending along it. The rack is in mesh with a ring of teeth (such as the teeth of a toothed belt or the teeth of a gear wheel) adapted to revolve about one axis (in the case of a gear wheel) or about at least two axes (in the case of a toothed belt). Such meshing engagement takes place in every position of the piston rod. When the piston rod is moved in the direction of its length the ring of teeth revolves about at least one axis and rotates a means for influencing the motion of the piston rod. Such means may for example be a liquid brake or a synchro transmitter connected with a NC unit controlling the supply of driving fluid to the piston and cylinder unit.

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.