Abstract: A drive assembly for adjusting the pitch of a wind turbine blade comprises a stator having a cylindrical body and a drive member positioned at least partially within the cylindrical body and movable along an axis thereof. A mounting pin extends through an aperture in a wall of the cylindrical body for pivotally mounting the stator to a wind turbine structure.

Abstract: A piston for cold chamber die-casting machines includes a piston body terminating at the front with a frontal surface pushing molten metal and at least one ring seat made around the body suitable to house a respective sealing ring. An annular distribution channel is made in an intermediate annular portion of the bottom surface of the ring seat, which communicates with the frontal surface of the piston through at least two communication holes made in the piston body for flow of molten metal into the distribution channel, under the ring. The communication holes are inclined in relation to the piston axis and have a through section which increases towards the distribution channel.

Abstract: An electromagnetic jack assembly. The jack has a first inner jack member having vertical walls, configured to slide within the base, the first inner jack member being nested within the base and having at least two walls connected to respective inside faces of the vertical walls of the base; a first linear magnetic drive assembly, comprising: a magnetic coil; and a magnet track, mounted on the base and the magnetic coil mounted on the first inner jack member or vice versa. The magnetic drive assembly forms the connection between the base and the first inner track. A second inner jack member nested within the first inner jack member and has a second linear magnetic drive assembly. The magnetic drive assembly forms the connection between the first and second inner track members.

Abstract: The present invention is a telescopic composite cylinder that functions as a hydraulic hoist incorporating multiple cylinders formed of composite materials. The walls of the multiple cylinders may be formed of pultruded composite material, or a combination of composite materials. The cylinders of the hydraulic hoist may incorporate a plurality of piston and sleeve assemblies that are mounted so as to invoke a telescopic relationship between the multiple cylinders. The materials that the cylinders are formed of may create walls having a smooth surface that can eliminate problems facing hoists formed of other materials, for example, such as a honing process, fluid leakage and seal wearing problems. The hoist may be run on diesel fuel drawn from the tank of a vehicle. Additionally, the present invention may be releasably attached to a surface by way of a saddle mounting system.

Abstract: A pump control assembly includes a fluid pump assembly having a fluid pump and a load sensing valve. The fluid pump includes a fluid inlet and a fluid outlet. The fluid pump includes a variable displacement mechanism. The load sensing valve is adapted to adjust the position of the variable displacement mechanism. The load sensing valve includes a first end and an oppositely disposed second end. An actuator is in fluid communication with the fluid pump assembly. A position sensor monitors the position of the actuator. A ramping valve provides selective fluid communication between the fluid outlet of the fluid pump and the first end of the load sensing valve. An electronic control unit is in electrical communication with the position sensor and the ramping valve. The electronic control unit transmits an output current to the ramping valve in response to the position of the actuator.

Abstract: An oil-gas separated pressure cylinder, which combines a hydraulic cylinder, a pneumatic cylinder and a pres-pressure cylinder, and keeps the applied compressed gas and the storage hydraulic fluid apart, maintaining the quality of the hydraulic fluid and saving the hydraulic fluid replacement cost. When the applied compressed gas enters the pre-pressure cylinder to move a pre-pressure cylinder piston in forcing the storage hydraulic fluid out of an oil storage space of the pre-pressure cylinder into an oil storage space in the hydraulic cylinder, a hydraulic cylinder piston of the hydraulic cylinder is then forced by the hydraulic fluid to move a hydraulic cylinder piston rod against the workpiece, and then a pneumatic cylinder piston rod of the pneumatic cylinder is forced into the oil storage space of the hydraulic cylinder to enhance the pressure at the hydraulic cylinder piston rod against the workpiece.

Abstract: Two-stage double-acting hydraulic cylinders are described, in which a first, inner stage includes a piston rod and head movable within a cylinder and a second, outer stage has a cylindrical body adapted to move longitudinally between stop positions intermediate the ends of the first cylinder. The two stages are hydraulically linked to each other through the alternate introduction of hydraulic fluid selectively through an extension pressure fluid port and a retraction pressure fluid port a limited motion of the outer stage is obtained in a power stroke. Hydraulic power means of this kind is of particular value in powered apparatus for digging and transplanting trees, where minimization of the overall height of the apparatus is desirable.

Abstract: An adjusting element with a closed first end, a cylinder, a piston displaceably arranged in the cylinder that divides the cylinder into a first work space remote of the first end and a second work space in proximity to the first end, and a piston rod which is arranged at one side of the piston and which projects through the first work space and is guided out of the cylinder concentric to or center longitudinal axis of the cylinder at a second end opposite from the first end so as to be sealed by a guiding and sealing device. The adjusting element has a device for detecting the piston rod position and/or the extended length of the adjusting element. The device for detecting the piston rod position includes a microswitch arranged at the cylinder and at least one switching element cooperating with the microswitch.

Abstract: A high inertance liquid piston engine-compressor that is lightweight, portable and for use with pneumatically actuated devices that may have periods of inactivity between periods of pneumatic use. The engine-compressor provides a power generation system that is for use with mobile or portable devices which need a portable long lasting energy source.

Abstract: A fluid pump (10) has a compression member (12) having a variably-sized compression surface (13b) movable against fluid pressure in a chamber (22). The effective surface area of the compression member (12) decreases in size together with a corresponding cross-sectional area of the chamber (22) from a maximal area at a beginning of the compression stroke to a minimal area at the end of the compression stroke. Using a variably-sized surface area to compress a fluid volume allows obtaining a rapid gain of fluid pressure even for applications in which the compression member (12) is actuated at relatively low frequencies and under the action of relatively small forces.

Abstract: A hydraulic actuator has an armored section having concentric cylinders and an unarmored section having a cylinder with a frangible piston and a frangible upper gland nut. The hydraulic actuator may have leakage vents adapted to prevent leakage between hydraulic systems used to power the cylinders. The hydraulic actuator also may have a gland seal for sealing an end of the cylinder of the unarmored section and a sensing port adapted for allowing detection of fluid leaking due to damage of the gland seal.

Abstract: An extendable sprinkler device comprises a base cylinder having a first end fluidly communicable with a second end via a through passageway. A primary extension assembly is coupled within the through passageway of the base cylinder and is positionable between collapsed and extended positions. The primary extension assembly comprises a primary extension cylinder having a first end fluidly communicable with a second end via a through passageway. A stop is coupled to the first end of the primary extension cylinder. An actuator cylinder is coupled within the primary extension cylinder. The actuator cylinder comprises a first end fluidly communicable with a second end via a through passageway. The second end of the actuator cylinder is coupled with the second end of the primary extension cylinder.

Abstract: The present invention is a telescopic composite cylinder that functions as a hydraulic hoist incorporating multiple cylinders formed of composite materials. The walls of the multiple cylinders may be formed of pultruded composite material, or a combination of composite materials. The cylinders of the hydraulic hoist may incorporate a plurality of piston and sleeve assemblies that are mounted so as to invoke a telescopic relationship between the multiple cylinders. The materials that the cylinders are formed of may create walls having a smooth surface that can eliminate problems facing hoists formed of other materials, for example, such as a honing process, fluid leakage and seal wearing problems. The hoist may be run on diesel fuel drawn from the tank of a vehicle. Additionally, the present invention may be releseably attached to a surface by way of a saddle mounting system.

Abstract: An integrated breakaway cylinder for controlling a boom of a self-propelled sprayer and method for constructing a boom assembly is disclosed in the present application. The integrated breakaway cylinder is constructed from a first stage cylinder and a second stage cylinder. The first stage cylinder is configured in a rod and barrel arrangement. The second stage cylinder is also configured in a rod and barrel arrangement, with the barrel of the first stage cylinder serving as the rod of the second stage cylinder. The first stage cylinder operates to extend and retract a boom. The second stage cylinder operates to absorb shock from inertia or the boom impacting an object. The design of various embodiments of the present invention couples the operation of maneuvering a boom with shock absorption into a single integrated cylinder.

Abstract: A debris guard is provided for an assembly having a variable length cylinder coupled to a housing. The cylinder has a barrel pivotally coupled to the housing and a rod which extends and retracts with respect to The barrel. The debris guard includes a body of flexible material filling a space between the barrel and the wall of the housing and preventing debris from entering the space. The body compresses as the barrel moves toward the housing wall and expands as the barrel moves away from the housing wall. The body of flexible material is bonded to a surface of the barrel and to the wall of the housing. The flexible material is molded and comprises a closed cell elastomeric material.

Abstract: The invention relates to an actuator for heavy machinery including a cylinder, a piston and a protective sleeve. The cylinder forms a chamber for receiving a fluid, and includes an external flange extending radially and outwardly from the cylinder. The piston is operable to translate axially relative to the cylinder between an open position and a closed position, and includes a first extremity positioned outside the cylinder and a second extremity positioned within the chamber. The second extremity sealingly engages the chamber. The protective sleeve protects the piston in the open position, which is movable with the piston and operable to overlap at least a portion of the cylinder in the closed position. The protective sleeve includes an internal flange extending radially and inwardly from the protective sleeve and is positioned for abutting the external flange when the piston is in the open position. This abutment limits the axial translation of the piston out of the cylinder.

Abstract: A multi-stage telescoping transmission jack with a high flow, lower pressure air-over-oil pump.

Abstract: Two telescopic lifting beams are loaded in their protruded position and are driven from a retracted position to a protruded position. In order to improve the bending strength of the lifting beams, the lifting beams are surrounded by two telescopic tubes, one of the tubes being fixed to the outer end of the telescopic first lifting beam and is slideable on the second telescopic tube, which extends inwardly on the second lifting beam.

Abstract: A telescopic cylinder comprised of an outer cylinder, a plurality of decreasing diameter piston/sleeve assemblies concentrically mounted in the outer cylinder for reciprocal axial movement relative thereto, and a plunger assembly concentrically mounted within the innermost one of the piston/sleeve assemblies for reciprocal axial movement relative thereto. The piston/sleeve and plunger assemblies having a piston with at least one lateral hole and at least one lateral passage, respectively, extending into its interior, and in fluid communication with a passage in the outer cylinder for receiving pressurized fluid. Each lateral hole having an orifice surface located at the radially outermost portion of the hole and having a diametral dimension no smaller than the maximum diametral dimension of the hole. Each piston further having at least one longitudinally relieved portion located on its outer circumferential surface extending from a first end towards a second end.

Abstract: A telescopic cylinder comprised of an outer cylinder, a plurality of decreasing diameter piston/sleeve assemblies concentrically mounted in the outer cylinder for reciprocal axial movement relative thereto, and a plunger assembly concentrically mounted within the innermost one of the piston/sleeve assemblies for reciprocal axial movement relative thereto. The piston/sleeve and plunger assemblies having a piston with at least one lateral hole and at least one lateral passage, respectively, extending into its interior, and in fluid communication with a passage in the outer cylinder for receiving pressurized fluid. Each lateral hole having an orifice surface located at the radially outermost portion of the hole and having a diametral dimension no smaller than the maximum diametral dimension of the hole. Each piston further having at least one longitudinally relieved portion located on its outer circumferential surface extending from a first end towards a second end.

Abstract: A telescoping hydraulic hoist which improves stability and rigidity in the extended position without sacrificing the maximum extension length of the hoist and with fewer machined parts which may be dislodged or damaged in operation. The base member has a recess into which intermediate and inner tube stages recede when the hoist is in a fully collapsed position, and a stop-collar on the gland nut bearings overlaps the exposed end of the next broader tube stage, defining a limit of retraction for each intermediate tube stage, so that a tube stage when fully retracted contacts the exposed end of the next broader tube stage, thus dispensing with the need for stop rings.

Abstract: A telescoping hydraulic hoist which improves stability and rigidity in the extended position without sacrificing the maximum extension length of the hoist and with fewer machined parts which may be dislodged or damaged in operation. The base member has a recess into which intermediate and inner tube stages recede when the hoist is in a fully collapsed position, and a stop-collar on the gland nut bearings overlaps the exposed end of the next broader tube stage, defining a limit of retraction for each intermediate tube stage, so that a tube stage when fully retracted contacts the exposed end of the next broader tube stage, thus dispensing with the need for stop rings.

Abstract: A telescopic piston assembly comprises a housing 1 containing an inner component 2, an intermediate component 3 and an outer component 6, all telescopingly interfitted together. The inner component 2 comprises a fluid outlet at one end, the intermediate component 3 making a sliding seal 5 with the inner component 2 and comprising a closed end surrounding the fluid outlet end. The outer component 6 makes a first sliding seal (12, FIG. 7) with the intermediate component 3 and a second sliding seal 13 with the inner component. A detent 4 operates to hold the outer component 6 in an extended position relative to the inner component 3.

Abstract: A seismic vibrator system for imparting compressional and shear wave vibrations into the earth has an earth contacting base with a vertical post. A tubular hub is slidably received on the post in a piston/cylinder relationship. Spaced apart horizontal top and bottom plates are secured to the hub. A mass is slidably supported between the plates. Pistons interconnect the hub and the mass. Hydraulic energy is used to reciprocate the mass vertically on the post and horizontally between the plates.

Abstract: A height-adjustable column has a stationary tube that receives a height-changing mechanism, such as a pneumatic spring having a cylinder and a rod that are axially movable with respect to one another. A transmitting mechanism includes a movable member that is operatively associated with the rod and is movable in a direction opposite to the direction of movement of the cylinder upon extension of the pneumatic spring when the pneumatic spring is in a predetermined lift zone.

Abstract: A telescoping hydraulic hoist formed from a non-corrosive material provides bearings and hydraulic seals about the bottom portion of each intermediate moving stage. The bearings and hydraulic seals are thus always maintained within the hoist and are not exposed to dust or particulate matter from outside the hoist. Air flows into and out of the air spaces between adjacent stages through air breathers. The hoist may also include variable length stroke limiters, and a cushion member which partially closes off the hydraulic inlet as the innermost stage is fully retracted to slow the hoist motion in the final stages of retraction.

Abstract: A small diameter cylinder 1a and a large diameter cylinder 1b connected to it are formed in a housing, and a stepped piston 8 comprising a large diameter part 8b and small diameter part 8a is inserted in these cylinders. A first pressure chamber 14a is formed on the small diameter cylinder side and a third pressure chamber 14c is formed on the large diameter cylinder side by the stepped piston 8, and an annular second pressure chamber 14b is formed on the outer circumference of the small diameter part of the stepped piston 8. An intermediate cylinder 10 is formed inside the stepped piston 8, and houses a piston 5 free to slide inside it which forms a fourth pressure chamber 14d. The fourth pressure chamber 14d is permanently connected to the third pressure chamber 14c. A rod 4 connected to the piston 5 passes through the stepped piston 8 in an axial direction. An end stopper 11 limiting the magnum stroke L1 of the piston 5 is provided, and sets the maximum stroke L2 of the stepped piston 8.

Abstract: A fluid-operated cylinder-piston unit has a cylinder forming an inner space, a piston unit movable in the inner space and including a first piston and a second piston movable relative to one another and each having a displacement area at one end and a force applying area at another opposite end. The pistons are arranged so as to form a smaller displacement area associated with one of the pistons and a larger displacement area associated with both of the pistons. A fluid supply to the piston unit is performed so that first only one of the pistons moves and another of the pistons remains stationary during an advance stroke, and during a return stroke fluid has to be applied only to the displacement area of the one piston, while thereafter another of the pistons is moved as well under the action of fluid and both pistons move to apply a larger force due the larger total displacement area and during a return stroke fluid is applied to the larger displacement area.

Abstract: A valve spring compressor apparatus for removing and installing valve springs on automotive racing engines includes a valve seat and a compressor pump assembly. The valve seat is placed between the valve spring and the engine housing. The compressor engages the valve spring seat with a support arm and extends a piston toward the valve spring seat, thus compressing the valve spring and allowing for the removal of the retainer ring and keeper lock. The compressor uses a source of compressed air to drive a power piston into a compression chamber multiplying the supply air pressure several times. This multiplied air pressure is retained in the extension piston chamber by a one-way valve. As the extension piston extends, the multiplied air pressure in the extension piston is maintained by repeated cycling of the compressor.

Abstract: An apparatus for cushioning a body of a dump vehicle when the body is lowered, including structure defining a fluid passageway between first and second end portions of the structure. The structure is adapted to be disposed in a fluid pressure operated actuator used to raise and lower a body of a dump vehicle. When the structure is disposed in such actuator the passageway extends in a longitudinal direction of such actuator and the second end portion communicates with an interior of such actuator. A cushioning spool is adapted to be connected to such actuator for moving in the longitudinal direction into the passageway. A poppet includes an orifice that receives the spool for enabling the poppet to be slidably movable on the spool in the longitudinal direction.

Abstract: A multiple-stage hydraulic cylinder for shifting loads by exerting different forces over different distances, in which a hollow-piston cylinder is provided with a hollow piston rod. The hollow piston rod accommodates at least one additional long-stroke cylinder. The hollow piston rod, moreover, comprising a cylinder tube surrounding the long-stroke cylinder. Connections are provided for hydraulic fluid to move the cylinders. These connections are provided on the hollow piston rod and the long-stroke cylinder for admitting fluid to move the hollow-piston cylinder and the long-stroke cylinder.

Abstract: A double acting hydraulic jack comprising a housing from which at least two pistons extend, each of the pistons being telescopic with respect to one another and with respect to the housing, and a counterbalance valve between adjacent pistons. The counterbalance valve allows hydraulic fluid to flow from an outer piston to an inner piston during piston extension and prevents back flow of hydraulic fluid, thus eliminating piston retraction during extension under load.

Abstract: The wire lock is provided for holding a stop ring on the outer surface of a cylinder. The stop ring includes a counterbore at one end thereof. The counterbore is positioned above an annular groove in the outer circumference of the cylinder. The wire lock is inserted into the registered counterbore and annular groove so as to prevent the stop ring from moving axially on the outer surface of the cylinder. The wire lock is accessible and visible from one axial end of the stop ring.

Abstract: A cylinder device which is capable of restraining the total length thereof to a shorter length even when the stroke is made longer, and which thereby provides the compact appearance and layout of, for example, a machine tool, in which the cylinder device is used. The cylinder device includes a first cylinder provided with an extensible piston rod. The piston rod is constituted as a cylinder tube of a second cylinder. The extensible piston rod of the second cylinder is formed in the interior thereof with a flow path for guiding a working fluid into a cylinder chamber of the second cylinder constituted by the piston rod of the first cylinder.

Abstract: A telescoping cylinder has a cylindrical housing (A) carrying a first stage including a central piston (B) opening into a hollow piston rod (C) and at least one succeeding stage including a concentric piston (E) and piston rod (F) having a hollow interior containing the central piston and piston rod with an air opening (H) in the concentric piston rod opening into an air outlet (G) at an exit end of the cylindrical wall. By applying compressed air to the central piston, the first stage is extended initiating movement of the concentric piston and piston rod with extension of the concentric piston and piston rod thereafter followed by extension of any succeeding stage. By applying compressed air to the outlet (G) the concentric piston (E) and piston rod (F) is retracted initiating movement of the central piston and piston rod when the air opening (H) in concentric piston rod (F) is aligned with port (G).

Abstract: A telescoping fluid actuator assembly including a housing having a plurality of concentrically disposed fluid actuators disposed therein. Each fluid actuator includes a cylindrical housing enclosing a piston and piston rod. Fluid passage means is provided for alternately directing fluid pressure to the front and back piston faces of each piston to effect forward and rearward movement of the pistons and the associated piston rod. The innermost concentric fluid actuator has a piston rod extending from the housing for engaging a workpiece for movement thereof. All of the concentrically mounted fluid actuators, except the innermost fluid actuator, is provided with a hollow piston rod which forms the cylinder housing for adjacent concentric fluid actuators.

Abstract: An hydraulic piston and cylinder unit with a piston rod and first and second cylinders. The piston rod extends into the first cylinder, and the first cylinder extends into the second cylinder. The piston rod is connected to a first piston which divides the first cylinder into first and second chambers. A second piston, connected to the first cylinder, divides the second cylinder into first and second chambers. The second chambers of the first cylinder, and the first chamber of the second cylinder are in fluid communication such that an extension of the first cylinder causes a proportional extension of the second cylinder. A similar effect occurs during retraction of the cylinders.

Abstract: This invention relates to a displacing apparatus comprising a plurality of concentric tubular members concentrically disposed about a central axial member. These concentric members define a plurality of substantially closed chambers between adjacent concentric members. A piston member is disposed within each chamber and extends generally radially between two adjacent concentric members thereby dividing each chamber into first and second portions. Each of these piston members is rigidly affixed to one, and sealingly engaged with the other, of the two adjacent concentric members forming a chamber. An actuating means actuates each of the concentric members which has a piston member rigidly affixed thereto. The actuating means selectively provides pressure or vacuum to the first and second portions of each of the chambers creating pressure differentials across the piston members.

Abstract: An indexing apparatus (10) having a pair of concentric cylinders (12, 14) with the outer concentric cylinder (12) being fixed against longitudinal movement and the inner cylinder (14) mounted for reciprocal movement relative to the fixed outer cylinder (12). A single ram piston (16) is mounted within the inner cylinder (14) and has a piston rod (18) connected to a member (29) for positioning at four predetermined positions. A shock absorber (24) is carried by the outer fixed cylinder (12) and engages stop plates or abutments (20, 28) carried by the inner cylinder (14) for activation of the shock absorber (24). A pair of guide rods (42) prevent rotational movement of inner cylinder (14) relative to the inner cylinder (12) and maintain the shock absorber (24) in axial alignment with the end abutments (20, 28). In one embodiment (FIGS.

Abstract: A multi-stage hydraulic actuator including a cylinder body having an outer cylinder and an inner cylinder provided in the outer cylinder, first and second pistons inserted in the outer cylinder to independently move and provided with first and second working members, and third and fourth pistons inserted in the inner cylinder to independently move and provided with third and fourth working members.

Abstract: A device for operation of a sliding door member, the device being movable between an open position in which the door member is open and a closed position in which the door member is closed. The device includes a pneumatic cylinder having an actuating piston and a rod assembly. A slidable cage sealingly sleeved between the cylinder and the piston reduces the force applied to the piston rod when approaching the open position. When moving towards the first position force is provided initially by conjoined movement of the piston and said cage, and finally by the piston only. A latch for locking the device in the closed position is provided by a spear secured to the piston and rod assembly and a pin to lock the spear disposed in the cylinder. A manual delatching can be achieved by a cable operated spool which moves the pin to unlock the spear.

Abstract: An upstanding telescopic cylinder including piston and cylinder sections is provided and the piston and cylinder sections include large, inner and outer relatively telescopingly engaged guide sleeves with the cylinder guide sleeve disposed outermost. The piston section includes small and large diameter guide discs slidably mounted thereon with the small diameter disc lowermost and the piston sleeve includes longitudinally spaced sets of circumferentially spaced notched abutments which successively engage and elevate the large and small diameter discs during extension of the piston section.

Abstract: A protective arrangement is described for a piston rod of an excavator hydraulic cylinder is arranged between a vehicle frame and a scraper blade to serve as a working cylinder for lifting and lowering. For protecting the exposed piston rod, a shell-type protective sleeve is supported by way of a stationary slide ring while resting on the latter, and encloses the piston rod from above in a protective manner during the working operation.

Abstract: A brake motor subassembly comprises a control piston (10) having an internal cavity delimited by a base wall (18) and, at the periphery, by a stepped bore (20, 22, 24) and having a mechanical actuating device acting on the control piston via an automatic compensation device formed by a screw-nut device (34) stressed towards the base wall, via a washer (26) and an axial thrust ball bearing (32), by a resilient member (28) supported on a ring (30) fixed at the end of the control piston axially opposite the base wall, and a pilot piston (44) having a first cylindrical peripheral surface of larger diameter (46) sealingly slideably cooperating with an end of reduced diameter (20) of the stepped bore and, in the vicinity of its end (50) axially opposite to the first peripheral surface (46) and cooperating with the washer (26), a second peripheral surface of reduced diameter (54) sealingly slideably cooperating with an annular seal (38) associated with a retaining washer (40) resting axially against a shoulder (42)

Abstract: An apparatus that raises and lowers a rotatable vestibule of the type used in airports to transfer passengers from a terminal building to a passenger loading bridge. A first plurality of telescoping columns are interconnected to and passively follow a second plurality of telescoping columns disposed interiorly of and in concentric relation with said first plurality of columns when the second columns are activated. J-shaped bushings made of Nylitron facilitate the extension and retraction of the columns and flat sections of that material provide additional bearing surfaces at other locations of the apparatus. The J-shaped bushing also provides stops that limit the extension of the apparatus.

Abstract: The invention concerns a cylinder-piston combination actuated by a pressure medium, comprising an outstretched cylinder space (1) and a two-part piston assembly (3, 8) movable in opposite directions in the longitudinal direction of the cylinder space (1). The piston rod (6) of the first part (3) of the piston assembly is of a tubular construction. The first part (3) is provided with a sealing between the piston (4) and the inner surface (2) of the cylinder space (1). The cylinder space (1) is provided with a connection (27) through which the pressure medium can be passed into the space (31) limited by the cylinder space (1) and the outer surface of the first part (3). The second part (8) is constructed to dimensions allowing it to fit inside the first part (3) and arranged to be movable relative to the latter. The combination includes an auxiliary piston (14) fitted around the piston rod (13) of the second part and sealed relative to the inner surface (2) of the cylinder space (1).

Abstract: Power fluid from a pump are provided through one power fluid branch conduit to an extend port for activating the smallest cylinder of a multi-stage packing cylinder and fluid is conducted through a second extend branch conduit to a second port which provides fluids to the larger cylinders of the packing cylinder. A normally closed sequence value is in the second branch conduit. When the pump first is activated, fluid goes through the first extend branch conduit to extend the smallest stage of the packing cylinder. When the smallest stage is fully extended or reaches resistance, the pressure in the pump output conduit rises. When this pressure reaches a preselected value, the sequence valve is opened and high pressure fluid is directed through the second branch conduit and second port to provide power fluid to the larger cylinders of the packing cylinder.

Abstract: The present invention provides a protective device for a working member, such as the piston rod of a piston and cylinder actuator, which is arranged at least partly in a receiving member and is able to be moved and more especially slid, along a curved or straight path so that it projects to a greater or lesser extent out of the receiving member. The device is provided with a plurality of sleeve-like guard sections which surround the working member projecting out of the receiving member along the full length of the working member so that whatever the position of the latter any two adjacent guard sections overlap each other and are able to be slid in relation to each other, one of said guard sections being stationarily arranged on the receiving member and another guard section being arranged on the working member so as to move therewith so that in accordance with the actual axial extent of the part of the member to be protected the sections are telescoped into each other to a greater or lesser extent.

Abstract: To allow a telescoping cylinder that is ordinarily operated in a fixed sequence to also be operated in a simultaneous mode, the first stage (12) of the cylinder is provided with an end plate (126), the cylindrical gap (114) in the first stage communicates directly with the space (133) inside the second stage (13) that is sealed off by the end plate, and a third cylindrical gap (124 & 124'), which is created in the second stage out of the sections (124 & 124') that are sealed off (1331) and derive from the end plate in the first stage, is provided with a pressure-medium line (23) that communicates through a telescoping passage (1131 & 1232) between the floor (111) of the cylinder (110 and the end plate (126) in the first stage, specifically satisfying the demand that the cylindrical gap (114) in the first stage (12) and the space (133) inside the first stage are equal in volume.

Abstract: A fluid operable power unit which is particularly adapted for movement of a compaction head in a refuse container. However, the power unit is also useful in other types of mechanism.The power unit comprises a plurality of telescopically movable cylinders and pistons. Fluid pressure is applied for movement of the first cylinder. Then increased fluid pressure is applied for movement of the second cylinder. As the first cylinder ceases to move, fluid pressure increases and automatically operable valve means traps the fluid which has moved the first cylinder. Then increased fluid pressure moves the second piston and second cylinder. As the second piston and the second cylinder move under the influence of increased fluid pressure, the fluid which is trapped is increased in pressure.Thus, high pressure forces act to move an actuator member for compaction or for any other purpose.