Abstract: A hydraulic pump to synchronize the operation of a pair of hydraulic actuators wherein each hydraulic actuator comprises a cylinder including a first fluid port and a second fluid port formed in the proximal and distal end portions thereof respectively and having a piston disposed therein coupled to a piston rod at least partially disposed within the corresponding cylinder. The dual hydraulic pump includes a triple gear assembly to alternately feed pressurized hydraulic fluid to the first fluid port of each hydraulic actuator simultaneously or the second fluid port of each hydraulic actuator simultaneously to synchronize the linear movement of each piston and piston rod in a first direction or a second direction.

Abstract: A hydraulic assembly for an extendable lift arm assembly can include an extension cylinder, a leveling cylinder, a main control valve, a flow combiner/divider, and one or more flow-blocking arrangements. The main control valve can be configured to control commanded movement of the extension and leveling cylinders of the lift arm assembly. The flow combiner/divider can be configured to hydraulically link the extension cylinder with the leveling cylinder for synchronized operation of the extension cylinder and the leveling cylinder. The one or more flow-blocking arrangements can be configured to restrict flow from rod or base ends of the leveling or extension cylinders during commanded extension or retraction of the leveling and extension cylinders, or in the absence of commanded movement of the leveling and extension cylinders, to maintain synchronized orientation of the leveling and extension cylinders.

Abstract: A hydraulic system for a work machine includes a first control cylinder to move a boom and a second control cylinder to move a bucket. A body of the first control cylinder has a first fluid chamber and a second fluid chamber. A first control valve is connected to the first fluid chamber via a first fluid path and connected to the second fluid chamber via a second fluid path to control the first hydraulic cylinder. A bucket positioning valve is connected to the second fluid path and a third fluid path to control a second hydraulic cylinder so as to rotate the bucket. A discharge fluid path is connected to the second fluid path between the bucket positioning valve and the first control valve. A discharge control valve is provided in the discharge fluid path to be opened and closed.

Abstract: A reagent cartridge which can be exchangeably inserted into an analyzer and having a plurality of reagent bags furnished with connecting lines, each of which may optionally be connected to an input device of the analyzer, and method for operating the analyzer are disclosed. Each reagent bag has an analyzer-controlled multi-way valve with at least two valve positions at the point where the respective connecting line departs, such that the first valve position opens a fluid path between the connecting line and the reagent bag, while the second valve position closes off the reagent bag and opens a fluid path between a ventilation source, e.g. ambient air, and the connecting line. The connecting lines of the reagent bags departing from the multi-way valve open directly into a common rail or a collector valve.

Abstract: A stack valve 1 includes an ascending dividing valve 14 which is provide on an ascending junction path 23 and controls the flow rate of a pressure fluid supplied to a head-side chamber 4a of a bucket cylinder 4, an ascending branched path 24 which is branched from the ascending junction path 23 and connected to an unloading path 21, and an ascending cancellation switching valve 19 which is provided on the ascending branched path 24 to close or open the ascending branched path 24. The ascending dividing valve 14 and the ascending cancellation switching valve 19 are provide in the same dividing section 83.

Abstract: A hydraulically operated valve control system includes a hydraulic flow divider including a hydraulic valve adapted to distribute, between two lines feeding respectively to actuators coupled to two inlet or outlet valves of a cylinder, the flow of oil coming either from a source of oil under pressure or from the feeding lines. The oil flow is distributed between the two feeding lines on the basis of the ratio of oil flow-rates in these two lines.

Abstract: The objective of the present invention is to provide a device that accurately communicates a subtle variation of an operation side to an action side. Specifically, in the present invention, an operating device is provided to perform a lock release operation of an extension device. The operating device feeds oil to a valve chamber by pressing a piston. When the flow rate of the fed oil is excessive, the valve is pressed to an opening resisting a biasing force of a compressed spring, thereby a rapid increase in the oil supplied to the action section is suppressed. Further, the supplied oil is suppressed to a very small amount by the throttle section, thereby an increase in the operation amount on the action section side is suppressed while maintaining the supply of the oil.

Abstract: A fluid pressure circuit that can, in either case where a first actuator that is fed from a first pump or a second actuator that is fed from a second pump is operated, by allowing feeding of the hydraulic fluid to a specific actuator from either the first or second pump, improve interlockability with the specific actuator. A control valve is incorporated with a plurality of first-group spools fed from a drive pump and a plurality of second-group spools fed from an idle pump. A solenoid selector valve unit switches a pilot line of a second-group tool controlling spool to a communicating state at the time of detection of a spool operation by a first pressure switch and switches a pilot line of a first-group tool controlling spool to a communicating state at the time of detection of a spool operation by a second pressure switch.

Abstract: A valve control unit that prevents a decline in interlocking operation performance when pilot pressure control of a plurality of pilot-operated control valves is carried out by proportional solenoid valves. First and second proportional solenoid valves include a Common Operation Table of lever operation amount/boom-up pilot pressure characteristics and are inputted with a common boom-up lever operation amount. A third proportional solenoid valve also includes the Operation Table and is inputted with a stick-in lever operation amount common to the fourth proportional solenoid valve. The fourth proportional solenoid valve includes an Operation Table of lever operation amount/stick-in pilot pressure characteristics different from that of the first, second, and third proportional solenoid valves and is inputted with the stick-in lever operation amount common to the third proportional solenoid valve.

Abstract: A synchronizing cylinder comprising a large diameter barrel and a small diameter barrel. The barrels are separated by a junction that is not fluidly sealed so that fluid can be communicated between them. The volume of the large diameter barrel is twice the volume of the small diameter barrel. The barrels comprise a first chamber adapted to communicate fluid to and from a hydraulic manifold, a second chamber adapted to communicate fluid to and from a first mechanism cylinder, and a third chamber adapted to communicate fluid to and from a second mechanism cylinder. The volumetric ratio of the barrels allows an equal volume of fluid to be communicated to and from the mechanism cylinders even though the volume of the barrels is not the same.

Abstract: On a work appliance, an extension arm is held rotatably, and a scoop is held rotatably on the extension arm. Actuation of the extension arm and of the scoop is by means of hydraulic cylinders. Each cylinder is assigned a valve which controls the flow of pressure medium from a pump to the cylinder and from the latter to the tank. A rotational movement of the extension arm is accomplished with the top edge of the scoop maintaining its angular position when the extension arm is being raised or lowered. Valves which control the flow of pressure medium to the cylinders are activated with the ratio of the pressure medium quantities supplied to the cylinders being kept at a constant value independently of the size of the control signal controlling the flow of pressure medium to a cylinder for the actuation of the extension arm.

Abstract: A synchronizing cylinder that allows for the synchronized movement of multiple hydraulic mechanism cylinders having different sizes and volumes. In one embodiment, the synchronizing cylinder has a first chamber in fluid communication with a first mechanism cylinder and a second chamber in fluid communication with a second mechanism cylinder. The first mechanism cylinder has a first volume and the second mechanism cylinder has a second volume wherein the volume of the first mechanism cylinder is smaller than the volume of the second mechanism cylinder. The volume of the fluid being pushed from (or received by) the first chamber in the synchronizing cylinder is less than the volume of fluid being pushed from (or received by) the second chamber in the synchronizing cylinder so that the first and second mechanism cylinders extend and retract at the same speed and distance regardless of the smaller size and volume of the first mechanism cylinder.

Abstract: A hydraulic grip-control unit provided with at least two gripping arms driven hydraulically to seize loads while cooperating with a striker arm of the grip with the control unit in use being connected hydraulically between a hydraulic fluid source under pressure and hydraulic cylinders each of which drives a gripping arm to form a closed supply circuit in which the source feeds fluid to the cylinders connected hydraulically in parallel and with the unit including a flow divider connected along said supply circuit between said source and said cylinders to apportion the flow of the circuit between the cylinders in parallel.

Abstract: There is disclosed a flow valve and a flow distributor for the pressure fluid supply of several consumers. Each flow valve includes a metering orifice and a pressure regulator. A pressure regulator piston of the pressure regulator is provided with two control edges one of which is active during “accumulating” of pressure fluid flows and the other is active during “dividing” of a pressure fluid flow. The flow valve moreover comprises at least one LS control edge by which a LS cross-section via which a pressure corresponding to the load pressure is indicated into a load-indicating line can be controlled to be opened when the pressure regulator is opened.

Abstract: What is disclosed is a control arrangement for an equipment, in particular a wheel loader or a backhoe loader having a shovel mounted articulatedly at a boom, wherein the control arrangement enables a control of the shovel by means of a control pressure of a boom control unit, so that the latter may be taken into a target position during lowering of the boom or while the boom is taken into a floating condition.

Abstract: A hydraulic system maintains squareness while extending an object via two lift cylinder assemblies. A hydraulic circuit is connected to the cylinder assemblies, and includes synchronizer with multiple isolated chambers corresponding to the cylinder assemblies, a rod extending axially through the chambers, and pistons mounted on the rod and associated with the isolated chambers. The hydraulic circuit operably connects a pump to the synchronizer and to the cylinder assemblies for controlling and providing synchronized movement of the cylinder assemblies. The hydraulic circuit includes valving for an automatic re-synchronization cycle, fill cycle, and air purge cycle. The system is effective for moving large objects in a non-binding manner, such as an extendable room on a recreational vehicle, while maintaining accurate squareness.

Abstract: A hydraulic platform lift, having hydraulic pump means and first and second hydraulic cylinders each having a piston member therein, each operatively coupled to a respective side edge of a platform to permit raising and lowering of the platform. A positive displacement valve is further provided, with the hydraulic platform lift and comprises a pair of juxtaposed cylinder members, each containing a longitudinally-movable piston, such pistons operatively coupled to each other so that movement of one piston causes an equal movement of the other. The positive displacement valve is adapted, when the pump means provides pressurized hydraulic fluid via a respective aperture to a first side of each of the pistons, to cause the pistons to be displaced an equal distance causing an equal egress of hydraulic fluid from the cylinder members via a respective aperture.

Abstract: A lift table maintains levelness while lifting a support surface via two or more lift cylinder assemblies. A hydraulic circuit is connected to the cylinder assemblies, and includes synchronizer with multiple isolated chambers corresponding to the lift cylinder assemblies, a rod extending axially through the chambers, and pistons mounted on the rod and associated with the isolated chambers. An axial passageway extends continuously through the rod and is connected to first passageways for communicating hydraulic fluid to one side of the chambers. The hydraulic circuit operably connects a pump to the axial passageway of the synchronizer and to second passageways connected to the chambers and to the cylinder assemblies for controlling and providing synchronized movement of the at least two lift cylinder assemblies. The hydraulic circuit includes valving for an automatic re-synchronization cycle, fill cycle, and air purge cycle.

Abstract: A hydraulic control apparatus which is used in order to prevent the blade from falling over on the pitch back side during a dual tilting operation, and to operate the left and right tilting cylinders in a uniform manner even in case where there is a large difference in the load pressure between the left and right tilting cylinders. In cases where it is desired to perform a dual tilting operation, the operator moves the operating lever either leftward or rightward while pressing the dual tilting switch of the operating lever. As a result of the switch being pressed, an electrical control signal that places the flow-combining/flow-dividing switching valve or flow-combining/flow-dividing valve in the flow-dividing position is generated by the controller, and the electrical control signal is output to the flow-combining/flow-dividing switching valve so that the flow-combining/flow-dividing switching valve or flow-combining/flow-dividing valve is switched to the flow-dividing position.

Abstract: In a multiple-switching valve having a bucket-leveling function, there are provided a diverged passage, which is diverged from a merged passage and connects with an unloading passage or a tank passage, and a switching valve to disconnect and connect the diverged passage. The switching valve allows a pressured oil drained from a rod-side chamber of a boom cylinder via a directional switching valve for boom to be supplied to the merged passage flow in the diverged passage, thereby preventing the pressure oil from being supplied to a head-side chamber of the bucket cylinder. Accordingly, the bucket-leveling function can be cancelled properly, thereby improving the operation of the multiple-directional switching valve.

Abstract: There is provided a flow divider system in a hydraulic circuit for a work machine including a boom cylinder and a bucket cylinder. The flow divider system divides a pressured oil drained from a one-boom cylinder into an other-bucket cylinder and a tank via a first orifice, a second orifice and a flow dividing valve, maintaining a specified pressure difference between pressures downstream the first and second orifices. The first and second orifice are configured of a variable orifice respectively, and in the event that the oil flow from the one-boom chamber decreases, respective opening degrees of the first and second orifices are controlled so as to be reduced. Accordingly, changing of a divisional ratio of oil flow can be suppressed properly regardless of a small oil flow drained from the boom cylinder.

Abstract: A divider combiner valve using only one spool without any springs. The correct holes open and close by ball and seat type check valves although these could be a poppet or disk as well and these valves may be located in the valve body, the spool, or both. These are simple and reliable. There is no chance of the holes not being in the correct location. Since there is only one spool, contamination cannot keep the spools from shifting into their correct relationship with each other. The extra pressure drops, needed to overcome the spring forces in the earlier designs, have been eliminated all together. Also, the number of spools has been reduced from two or three down to a single spool, thus reducing the cost to manufacture the finished valve. Because there is only one spool, clearances are closer. There is less internal leakage, more accuracy while the cylinders are in motion. This closer clearance tends to lock the loads rather than transfer oil from one cylinder to the other.

Abstract: An industrial lift truck has a boom that is raised and lowered by a first hydraulic actuator and a load carrier that is pivoted with respect to the boom by a second hydraulic actuator. In the event that the supply of hydraulic fluid for powering the actuators fails, the boom may be lowered by gravity by draining fluid from the first hydraulic actuator. To prevent a load from sliding off the load carrier as the boom descends, the load carrier is pivoted to maintain a substantially constant angular relationship to the ground. This is accomplished by selectively conveying fluid drained under pressure from the first hydraulic actuator into the second hydraulic actuator. Changes in the position of the boom are sensed and, in response, the flow of fluid into the second hydraulic actuator is controlled to produce corresponding changes in the load carrier position.

Abstract: An implement/vehicle hitch system for coupling implements to a utility vehicle includes two hydraulic cylinders for adjusting the position of the implement. The hydraulic cylinders are connected to a pair of motor/pump units which cause the hydraulic cylinders to operate in a synchronous manner.

Abstract: An industrial lift truck has a boom that is raised and lowered by a first hydraulic actuator and a load carrier that is pivoted with respect to the boom by a second hydraulic actuator. In the event that the supply of hydraulic fluid for powering the actuators fails, the boom may be lowered by gravity by draining fluid from the first hydraulic actuator. To prevent a load from sliding off the load carrier as the boom descends, the load carrier is pivoted to maintain a substantially constant angular relationship to the ground. This is accomplished by selectively conveying fluid drained under pressure from the first hydraulic actuator into the second hydraulic actuator. Changes in the position of the boom are sensed and, in response, the flow of fluid into the second hydraulic actuator is controlled to produce corresponding changes in the load carrier position.

Abstract: A hydraulic control system for controlling the orientation of a material handling unit on a lift boom. The control system includes a flow divider/combiner valve operative in a boom-raise, unit-leveling mode to pass a portion of the fluid displaced from the rod end of the boom cylinder to the base end of the unit cylinder, and operative in a boom-lower, unit-leveling mode, to combine the fluid stream displaced from the base end unit cylinder in a preset ratio with pressurized fluid, and pass the combined stream to the rod end of the boom cylinder. A modulating valve controls flow to and from the base end of the boom cylinder and is pilot actuated to inhibit descent of the boom until the pressure in the unit cylinder reaches a level at which the unit cylinder initiates levelling of the unit.

Abstract: Apparatus for equalizing pressure between two conduits including means for sensing pressure in said conduits; valve means communicating between said conduits, said valve means adapted to open so as to equalize pressure between said conduits.

Abstract: A control system for a lift boom pivotable with respect to a vehicle by a boom cylinder and material handling unit pivotable with respect to the boom by a unit cylinder when the control of a boom control valve and a unit control valve. The control system includes a flow divider/combiner valve and operative in a boom-raise, unit-leveling mode to pass a preset portion of the fluid displaced from the rod end of the boom cylinder to the base end of the unit cylinder. The flow divider-combiner valve is operative in a boom-lower, unit-leveling mode, to combine the fluid stream displaced from the base end unit cylinder in a preset ratio with pressurized fluid, and pass the combined stream to the rod end of the boom cylinder. The control system can be disengaged from the automatic leveling mode to enable the boom unit to be operated manually under the control of the boom and unit control valves.

Abstract: A proportional flow divider valve is configured only as a controlled flow valve by using a first spool in a valve body or as both a free flow valve as well as control flow valve by using a second spool in the valve body. The second spool is provided with a return fluid check valve which is integral therewith and disables the control flow mode when pressure is applied to a piston surface on the return flow check valve. The return flow check valve is configured as a split sleeve which fits around a lateral inlet passage through the second spool and is urged to close the lateral inlet passage under pressure from returning hydraulic fluid. Normally, the split sleeve is axially biased by a vented coil spring to open the lateral inlet passage in the spool.

Abstract: A hydraulic control circuit comprises a power unit, a central processing unit, at least one feedback sensor, a valve manifold, and two or more hydraulic lifting cylinders interconnected with miscellaneous hydraulic hoses and electrical wiring. Basic lifting is regulated by a flow divider unit configured to distribute a flow of pressurized hydraulic fluid pumped from a fluid reservoir through the valve manifold to each of the lifting cylinders during a lifting operation. To compensate for any imbalance between the lifting cylinders, the central processing unit monitors the movement of the lifting cylinders, and is configured to divert, through a three-way valve in the valve manifold, an additional portion of the pressurized fluid flow to a lagging lifting cylinder.

Abstract: A self-leveling system controlling a boom (13) and a bucket (15) by double acting cylinders (17, 19). The system includes a self leveling valve assembly (27) including a first valve section (27a) including a flow divider spool (41) whereby flow from the rod end of the boom cylinder (17) is divided, one portion flowing to the head end of the bucket cylinder (19). The valve assembly also includes a second valve section (27b) including a flow dividing spool (61), whereby flow from the head end of the boom cylinder (17) is divided, a portion flowing to the rod end of the bucket cylinder, as the boom (13) is lowered. The self leveling valve assembly (27) includes capability whereby, even when the bucket cylinder (19) is fully extended or fully retracted, it is still possible to operate the boom cylinder (17).

Abstract: A compensation system for a hydraulic circuit of a hydraulically driven vehicle for straight traveling, with left and right traveling valves having load detection ports; left and right pressure compensation valves arranged in respective pressurized fluid supply passages between a fluid pressure source and the traveling valves; and a by-pass passage for connecting together the load pressure detecting ports of the left and right traveling valves. There may be an on-off valve in the by-pass passage.

Abstract: The invention relates to a method for, in a hydrostatic transmission having a preferably variable displacement hydraulic pump (P) feeding a number of hydraulic motors (M1, M2, M3, M4) provided in association with respective drive wheels, drive tracks or corresponding drive apparatus, mutually balancing the flow of hydraulic fluid through the different hydraulic motors (M1-M4) by individually controlling of the flow from and/or to the same, whereby the individual flows of hydraulic fluid through the respective hydraulic motors (M1-M4) are detected and compared across respective restrictions (14, 15) being variable dependent on the total flow but being of mutually equal size and whereby, for optimum control or balancing, the detected differences in flow through the different hydraulic motors are in themselves used directly for the balancing.

Abstract: A self-releveling, height adjustable, hydraulically operated desk and a hydraulic circuit therefor are disclosed in which the desk top is supported for vertical movement upon master and slave rephasing cylinders connected in series. The desk top may be releveled by extending the cylinders to their limits of extension. The desk and circuit may include a height adjustable monitor support. The monitor support may also be supported for vertical movement upon master and slave rephasing cylinders for self-releveling. The hydraulic circuit includes check valves to prevent the desk top and the monitor support from being raised with respect to the supporting structure except upon activation of the hydraulic pump.

Abstract: A control device for hydraulic operating cylinders of a combined lifting platform and closing wall of a vehicle, having a hydraulic fluid pump (1), driven by a motor (2), which pump can be made to communicate with a fluid supply (4) and, via pump branch lines (8', 8") beginning at a pump line (8), with a chamber of at least one lifting cylinder (11) and of at least one closing cylinder (14) of the lifting platform and closing wall, respectively, via associated control valves (9, 10; 12, 13), wherein a pressure transformer and piston cylinder unit (15) is connected parallel to the pump branch lines (8', 8").

Abstract: A drive system for a work vehicle is provided which includes first and second hydrostatic transmissions which are responsive to respective control signals for driving first and second ground engaging devices at a rate responsive thereto. A sensor is provided sensing the position of a manually operable control element and responsively producing a desired speed signal. A memory device is adapted to store data relates the desired speed signal to the first and second control signals in a preselected manner. A processor is provided for receiving the desired speed signal, responsively retrieving at least a portion of the data from the memory device, and producing the first and second control signals in response to the retrieved data and the desired speed signal. An adjusting device is provided for receiving at least one of the control signals, permitting controllable adjustment of the control signal so as to vary the speed of a respective ground engaging device.

Abstract: A control system for the hydraulic operating circuit associated with a vehicle lifting device in which the circuit is provided with pressure fluid control valves and flow sensors which are operative on the vehicle lowering cycle to establish substantial evenness of the lowering mechanism and protection against malfunction of an operating component to arrest the travel of the vehicle lifting device in its lowering cycle.

Abstract: A system reduces force fight between hydraulic actuators (22, 24) operated on independent hydraulic circuits (29, 49) which position a control surface (20) of an aircraft. Each circuit includes a hydraulic supply (30, 50). A pressure equalization valve (70) is connected to first sides (42, 62) of the actuators. In the event of a pressure imbalance, a spool (82) shifts in the pressure equalization valve. Movement of the spool enables fluid from the circuit supply to be delivered through the equalization valve to the actuator at the lower pressure, rapidly eliminating the imbalance.

Abstract: A fluid powered actuator system includes two identical fluid powered actuators operable by respective supply pressures which are controlled by respective identical valve arrangements. Operating positions of flow control elements of the valve arrangements are applied through respective couplings to a differential arrangement which operates, if these positions differ by an unacceptable amount, to apply an error indication through respective coupling to prevent the supply pressures from being applied to the respective actuators.

Abstract: A hydraulic system for lifts provided with two independently supported parallel platforms comprises at least two cylinder-piston units (80, 81) for raising the platforms, a metering device (7) for feeding identical quantities of fluid to said two units, and a balancing device (74, 75) operated by means (31, 32) for measuring the height difference between the platforms and arranged to feed a quantity of supplementary fluid to that cylinder-piston unit (80) or (81) operating the lower platform by withdrawing it from that cylinder-piston unit (81) or (80) operating the higher platform.

Abstract: A hydraulic press having at least two cylinders adapted for providing relative displacement between the upper and lower platens of a hydraulic press, each cylinder being in fluid communication with only one chamber of a multiple chamber hydraulic system utilizing a common ram operating through all chambers, the ram portion in each chamber having a predetermined ratio of area of the ram in the direction of actuation to volume of hydraulic fluid within its chamber to provide equal find displacement in each chamber or movement of the ram.

Abstract: An apparatus for synchronizing a plurality of actuators, comprising a pressure fluid source 15 associated with a setting device 6, with transmitters 10 of the movements of the operating members 5, and also with multichamber adding elements 17 equal in number to the actuators 4 to be synchronized.

Abstract: A hydraulic circuit for pitch and tilt control of a dozer blade attached to push arms on a vehicle with a pitch ram connected between one push arm and the blade and a dual actuator consisting of a second pitch ram and a tilt ram connected at their head ends. A pitch valve directs hydraulic fluid to and from the pitch rams with a diverter/combiner valve interposed therebetween to assure a flow of fluid either to said rams or from said rams at equal rates. Pilot-operated check valves hydraulically lock the pitch rams until opened by pressure directed from said pitch valve. Tilt and lift valves directs fluid pressure to and from the tilt ram and a lift ram respectively with regeneration capability for both tilt and lift functions.

Abstract: This invention teaches an improved collapsible farm implement of the type having a wheeled frame or cart and right and left side elongated toolbars pivoted at their inboard ends about vertical axes relative to the frame so as to allow toolbar rotation rearward through approximately a quarter turn between a fully elevated field use position disposed crosswise to the path of implement travel and a road transit position disposed parallel to the path of implement travel. A wheeled truck assembly is mounted near the outboard end of each toolbar for providing rolling support of the latter, and each wheeled truck assembly can be rotated relative to the toolbar about an axis disposed substantially normal to the toolbar through approximately a quarter turn operable to steer the outboard end of the toolbar, upon appropriate forward or rearward implement movement, between the respective fully elevated field use and road transit positions.

Abstract: A safety circuit for preventing uncontrolled descent of a hydraulically supported load, in the event of a leak, comprises parallel hydraulic pressure feed lines, control valves in these, and means responsive to a difference in pressure between the lines and arranged to close the valves when such a pressure difference is detected. The valves are provided adjacent to a lifting cylinder or cylinders and close to the pressure source, so as to prevent spillage of hydraulic fluid as well as to prevent descent of the supported load.

Abstract: An actuator system characterized by parallel connected flow regulator valves for controlling the flow of fluid to and from the extend ends of a corresponding number of fluid actuators. Retract orifices in the fluid lines leading to the retract ends of the actuators prevent cavitation of the extend ends of the actuators under an aiding air load pulling the actuators out during extension thereof.

Abstract: The safety device includes a self-closing cylindrical gate which, in closed position, blocks the hydraulic conduit surrounding the hydraulic turbomachine; the gate is housed, in the open position, in a chamber including two components near the hydraulic conduit defining wth the gate two orifices situated upstream and downstream with respect to the gate; pressure on top of the gate takes an intermediate value between the upstream and downstream pressures, and is determined by the ratio of the product of the discharge coefficient with the passage cross-section upstream orifice over the product of the discharge coefficient with the passage cross-section downstream orifice, so that a pressure is exerted on the upper edge of the gate, resulting in a force which tends to move the gate to close the hydraulic conduit.

Abstract: A fluid powered actuator system has first and second piston actuators, the fluid flows to and from which pass through first and second flow paths which include respective first and second valve devices, the valve devices being coupled for operation in unison and being responsive to the flow levels therethrough, so that the valve devices operate to equalize these flows and thereby to equalize the rates of movement of the piston actuators. A further valve is responsive to a predetermined level of difference between the flows in the first and second paths to apply a servo actuating pressure which urges the first and second valve devices to a position in which flow to or from the piston actuators is prevented.

Abstract: An implement having a rotary flow divider controlling fluid to and from at least two independent hydraulic rams for raising and lowering the implement in a level manner. A counter totals the revolutions of the flow divider and actuates an electrical circuit which controls solenoid valves to stop the implement at the proper height.

Abstract: An agricultural implement having a frame with a pair of wheel assemblies capable of being rotated on the frame by a pair of hydraulic rams to raise and lower the frame relative to the ground. A direction control valve is connected to one end of the ram cylinders and the other ends of the ram cylinders are connected to the direction control valve through a rotary flow divider. A spring-seated check valve is connected across each of the metering gear sets of the rotary flow divider to permit flow to be diverted from a fully extended ram to one that is not yet fully extended.