Abstract: An electric tool (1) includes piston (36) reciprocably housed in cylinder (34) provided in main body portion (10) and be pushed by a pressure of fluid; tool head (14) coupled to a distal end of the main body portion and performing a predetermined operation by being pushed by the piston; return channel (40) communicating from the cylinder to a fluid tank to allow the fluid to flow therethrough; pressure regulating valve (44) disposed in operational flow channel (42) branching from the return channel and taking an open position when the pressure of the fluid in the return channel becomes equal to or higher than a predetermined value; operating pin (46) disposed in the operational flow channel and pushed by the pressure of the fluid flowing therein; and return valve (48) disposed in the return channel and taking an open position by being pushed by the operating pin.

Abstract: A reserve fuel tank retention and control (RTRC) module and a method of operating a vehicle including an engine and a main fuel tank containing a fuel, the method including mounting the RTRC module onto the vehicle; fluidly connecting the RTRC module to the engine and to the main fuel tank; actuating a valve of the RTRC module for a predetermined time to purge moisture in a fuel supply hose into the engine; and upon the main fuel tank becoming empty, actuating the valve to allow fuel from the reserve fuel tank to supply the engine.

Abstract: An integrated valve includes a body portion, a flow rate adjustment valve body, a flow passage switching valve body, and a shaft member. The body portion has formed therein a plurality of passages. The flow rate adjustment valve body is provided inside the body portion that adjusts a flow rate of fluid. The flow passage switching valve body is provided inside the body portion configured to switch a flow path of the predetermined fluid in the fluid circulation circuit, the flow passage switching valve body being switchable between distinct communication states. The shaft member is provided inside the body portion that interlocks the flow rate adjustment valve body and the flow passage switching valve body.

Abstract: A vehicle heat pump system is provided. The system includes a battery coolant line connected to a battery module and into which a coolant flows. A cooling device includes a radiator and a first water pump connected to a coolant line, to circulate a coolant in the coolant line to cool electrical equipment, and to be selectively connected to the battery coolant line via a first valve. A chiller is disposed in the battery coolant line, to be connected to a refrigerant line of an air conditioner via a connecting line, and to adjust a temperature of a coolant or a refrigerant by selectively exchanging heat between the coolant and refrigerant flowing into the chiller. An integrated control valve is connected to the refrigerant line and the connecting line to adjust a refrigerant flow direction and to selectively expand a refrigerant passing through the inside of the integrated control valve.

Abstract: A valve system for use with a cylinder having an extensible rod, includes first and second valve assemblies, each including an inlet/outlet port configured to selectively be coupled with a source of pressurized gas, a check valve biased toward a closed state and having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the inlet/outlet port and the check valve, and an inlet pilot port connected with the check valve for opening the check valve when supplied with pressurized gas. First and second pilot lines extend to the respective inlet pilot ports from respective outlet pilot ports of the opposite ones of the first and second valve assemblies. When pressurized gas is supplied to the inlet/outlet port of a valve assembly, pressurized gas is also supplied to the opposite inlet pilot port.

Abstract: A fluid system with a safety-oriented valve assembly including a first fluid connection for a fluidic connection with a fluid connection of a fluid source or a control valve and a second fluid connection for coupling a fluid load as well as a fluid channel between the fluid connections, wherein a first valve can be actuated between a fluid supply position, or open position, and a fluid discharge position, or closed position, is arranged in the fluid channel, wherein a second valve which can be adjusted between an open position for the fluid channel and a throttle position for the fluid channel is arranged in the fluid channel and wherein a sensor for detecting a fluid pressure and for outputting a fluid pressure-dependent sensor signal is arranged in a section of the fluid channel between the first valve and the second valve and including a controller which is designed to process the sensor signal and to process control signals for the valve.

Abstract: A lubrication loop includes a main flow path connected to a lubrication flow path, a control valve connected to the main flow path, a return flow path connected to the control valve and configured to return the fluid to the fluid pump, and a sub-flow path branching off from the main flow path. The control valve includes a discharge port at a distance from a supply port of a valve housing chamber and connected to the return flow path, an open port formed at one end of the valve housing chamber to discharge the fluid, an annular recessed portion formed on an outer circumferential surface of the spool has a width extending from the supply port to the discharge port, and a sub port annularly formed between the discharge port and the open port on an inner circumferential surface of the valve housing chamber and connected to the sub-flow path.

Abstract: A first valve member switches between a first communication state, in which a first inlet passage communicates with a first outlet passage and a second inlet passage is closed, and a second communication state, in which the second inlet passage communicates with the first outlet passage and the first inlet passage is closed. A second valve member switches between an opening state and a throttle state in which a smaller volume of a fluid flows from the third inlet passage to the second outlet passage as compared to the opening state. A valve driving member switches between a first operation state, in which the first valve member sets the first communication state and the second valve member sets the opening state, and a second operation state, in which the first valve member sets the second communication state and the second valve member sets the throttle state.

Abstract: An inking system of a printing press includes an impression cylinder for guiding a printing substrate, and at least one ink-transfer roller. The ink-transfer roller includes a cylinder mandrel, on which at least one cylinder sleeve is concentrically displaceable, and bearing blocks, in which ends of the ink-transfer roller are mounted and which are independently displaceable in the radial direction of the impression cylinder. The ink-transfer roller can be set against the impression cylinder or any other ink-transfer roller, with a bearing block being detachable from one end of the ink-transfer roller and displaceable relative to the ink-transfer roller so that the cylinder sleeve can be removed via this one end. A stop device, with which the cylinder sleeve can be brought into contact, has components that are movable in the axial direction of the print roller. The movable stop device components can be decelerated via a force-providing element.

Abstract: A zero emission reciprocating drive pump. The reciprocating drive pump may comprise: a spool and housing assembly. The housing assembly may comprise a flange, spool housing, first chamber, second chamber, and first seal. The flange may attached to a proximal end of the spool housing. The first chamber may be within the flange. The second chamber may be within the spool housing. The spool may be substantially disposed in and reciprocally movable in the second chamber. A proximal end portion of the spool may move reciprocally into and out of the first chamber. The first seal may be positioned substantially adjacent to the first chamber and the second chamber and may contact the proximal end portion of the spool. The flange may comprise a lip that extends substantially along a width of a distal end of the first seal, such that the first seal does not pop out of place.

Abstract: A valve system for controlling a system pressure control system, in particular a hydraulic control unit of an automatic transmission, includes a multi-stage system pressure valve, a pilot valve and a control valve with a control piston downstream from the pilot valve that governs the pressure at a differential area of the system pressure valve, depending on the pilot pressure. The pilot pressure/system pressure characteristic curve features a continuous development, and whereas, from a predefined pilot pressure, on the basis of a sudden change to the dependency of the change to the system pressure as a function of the change to the pilot pressure, the gradient of the system pressure as a function of the pilot pressure is significantly steeper than that prior to the predefined pilot pressure.

Abstract: A pump apparatus includes: a pump that ejects a hydraulic fluid; and a selector valve that switches a direction of a flow of the hydraulic fluid to be supplied to one of a first chamber and a second chamber of a cylinder apparatus, which is internally partitioned by a piston into the first chamber extending during an extending stroke of the cylinder apparatus, and the second chamber extending during a shortening stroke of the cylinder apparatus, and the selective valve has, at a channel connected to the second chamber, an orifice that is narrower than a channel connected to the first chamber.

Abstract: A fuel injector for injecting fuel in a burner of a gas turbine where the fuel injector has a body with an inner hole and a valve element which is slideably arranged inside the inner hole. The body has a fuel inlet which is formed into the body for injecting fuel into the inner hole, wherein the fuel inlet is coupleable to a fuel supply line. The body further has a first outlet channel connected to the inner hole, wherein the first outlet channel is further coupleable to a burner. The valve element has a first passage which is formed such that in a first position of the valve element inside the inner hole, the first passage connects the fuel inlet with the first outlet channel and in a second position of the valve element inside the inner hole.

Abstract: A reciprocating drive mechanism. The reciprocating drive mechanism may comprise: a spool assembly and a spool housing. The spool assembly may be reciprocally movable within a spool chamber of the spool housing. The spool housing may comprise a first seal, a second seal, and a third seal. When the spool assembly is within the spool chamber, the first seal, the second seal, and the third seal may divide the spool chamber into a distal chamber, an intermediate chamber, a supply chamber, and a proximal chamber, respectively. The spool assembly may comprise a first spool vent that is in fluid communication with the distal chamber. The spool housing may comprise a first housing vent that is in fluid communication with the intermediate chamber. The first spool vent may be in fluid communication with the first housing vent when an outlet of the first spool vent is aligned within the intermediate chamber.

Abstract: A system and method determine when fluid is not flowing properly from a secondary infusion source during a secondary infusion. The system includes an upstream pressure sensor and a processor programmed to receive signals from the sensor and analyze the signals to determine if secondary fluid flow is proper. The processor samples the output signals from the upstream pressure sensor and analyzes the sampled signals to determine if a pressure rise in the infusion line has occurred when the secondary infusion is initiated. If a pressure rise, indicating that fluid from the secondary container has begun flowing into the infusion line, has not been detected, the processor is programmed to provide a signal indicating that attention should be given to the infusion set up.

Abstract: A valve assembly for receiving a fluid under pressure and comprising a plurality of valves in a single valve block. The assembly may include a plurality of check valves and including a counterbalance generating valve and a 3-way valve and including a method of use. The assembly may include an adjustable counterbalance valve, a pilot-operated check valve and a 3-way valve or combinations thereof.

Abstract: A counterbalance valve is provided with load-sensing, hydro-mechanically setting, features. The counterbalance valve relief setting changes dynamically based on the load pressure at the load port of the counterbalance valve.

Abstract: A controlling device for hydraulic consumers (10, 12) has one controlling valve (18) for controlling a supply pipeline (TReg) for the hydraulic consumer (10, 12) and a tank return pipeline (TRO). Because the control valve (18) is connected to an additional supply pipeline (TR) and constructed as a priority valve, the supply pipeline (TReg) receives priority preference of a fluid supply system over the priority of the tank return pipeline (TRO). A sensor circuit is realized which checks whether, in accordance with the load situation at the hydraulic consumer (10, 12), there is any need at all for a supply flow.

Abstract: A method for operating a hydraulic actuation system during a pressure sensor malfunction is provided. The hydraulic actuation system includes a pump, a reservoir, a first work-port and a second work-port, a valve system with individual orifices, a pressure sensor system, and a controller for regulating the hydraulic actuation system based on fluid flow demand and on determined pressure differences. The method includes detecting a malfunction of a pressure sensor for the first work-port, closing second and third orifices, and regulating the pump to generate fluid flow corresponding to maximum pressure generated by the pump. The method also includes assigning a value for the difference between pump pressure and the pressure of the subject work-port that is equivalent to a value within an attainable range for difference between the two pressures. Furthermore, the method includes regulating a first orifice and a fourth orifice in response to the fluid flow demand.

Abstract: A reversing valve is provided having a generally cylindrical valve housing and a rotatable valve body positioned within at least partially within the housing, the valve body has a first fluid pathway and a second fluid pathway, each fluid pathway generally shaped as a “y” such that there are six openings into the body. A motor rotates the body to align the fluid pathways of the body with four openings in the housing in a first position and rotates the body 180 degrees to a second position aligning the fluid pathways of the body with four openings in the housing in a manner allowing reverse flow through the valve. At least one opening of each fluid pathway is blocked by the housing when the body is in either the first or second position.

Abstract: A hydraulic actuator is connected between a downhole tool and a hydraulic control line for operating the downhole tool through an actuation sequence. The hydraulic actuator comprises a valve shuttle section having an inlet port in connection with the hydraulic control line, a first function port and a second function port. The hydraulic actuator also has a shuttle movable between positions providing fluid communication between the inlet port and the first function port and the inlet port and the second function port. Additionally, the hydraulic actuator has a pilot assembly in fluid connection with the hydraulic control line and in operational connection with the shuttle. The pilot assembly is movable in response to an actuation cycle comprising applying pressure from the hydraulic control line and bleeding the pressure off.

Abstract: In order to minimize shift shocks during R?N and D?N manual shifts, in a manual valve of a hydraulic control system of a continuously variable transmission including a valve body having one input port and two output ports and a valve spool having a first land and a second land connecting the input port with one of the two output ports or completely blocking the input port from the two output ports, each land includes slots configured such that inner ends of the slots can be connected to the output ports in a neutral state.

Abstract: A lock valve includes a lock valve body having a bore with a valve spool reciprocatingly received therein. There is a check valve adjacent each end of the bore. Each of the check valves has a check valve member facing the bore and resiliently biased towards a valve seat at each end of the bore. A pressure relief port communicates with the bore near the center thereof and between lands of the valve spool. A pair of spaced-apart grooves are disposed within the spool valve bore. Each groove permits fluid communication past a land of the valve spool when the valve spool is displaced towards one end of the bore by fluid pressure applied to other end of the bore so as to unseat the check valve member adjacent to the one end to the bore and allow pressurized fluid to pass from the one end of the bore, through the groove, and into the relief port.

Abstract: The invention relates to a safety shut-off device for sections of fluid circuits, which in case of damage or the like, have to shut off from each other on safety considerations. The safety shut-off device includes two chambers with connections for the sections to be shut off from each other. The chambers are separated from each other by a piston and have two connections each, of which one is closed by closing elements with sealing force elements, when both chambers have the same pressure. Further, two actuating devices are provided which are functionally connected to the closing elements and the piston. When the piston is moved due to a pressure difference between the connections, the closing element in the chamber with the higher pressure opens the associated connection so that fluid can flow from a section with higher pressure into the other section with lower pressure.

Abstract: The invention relates to a pneumatic open- and closed-loop control apparatus (10) for flows of pressure fluid, having one inlet conduit (14), two outlet conduits (16, 18), and one venting conduit (20), and also having a valve piston (90) mediating between these conduits and mounted in a valve chamber (92), and to a method for open- and closed-loop control of flows of pressure fluid. It is proposed that by means of a pneumatically driven valve piston (92), with a predeterminable time constant, one outlet conduit (16, 18) each of the pneumatic open- and closed-loop control apparatus (10) is connected to the single inlet conduit (14), while the other outlet conduit is simultaneously connected to the venting conduit (20).

Abstract: The invention relates to a valve combination which is characterized in that the valve combination has a passive valve and an active valve. The active valve is provided with means for an active influence of the control position of a closing element and regulates the fluid flow at a high pressure. The passive valve controls the fluid flow at low pressure. The passive valve and the active valve are integrated into the cooling system pump circuit such that the pressure difference between the high and low fluid pressure and the control positions of the active valve determine the control position of the passive valve.

Abstract: A filtration and backwash system for a water source such as a swimming pool is provided including a fluid source, a pump, a filter and a specially designed five-port valve which is easily adaptable for automatic use in the filtration mode and in the backwash mode. The valve uses a rotatable deflector plate which is positioned to divert the fluid in one direction in the valve for the filtration process and is positioned to divert the fluid in the other direction in the valve for the backwash process. An automatic timing device is also provided and is particularly suitable for use in conjunction with the valve whereby no manual intervention or electronic means is needed to change the valve from the filtering mode to the backwash mode or vice versa. The timing device automatically senses the pressure buildup in the filtration system due to accumulation of debris in the filter and automatically changes the valve from the filtration mode to backwash mode when a predetermined system pressure is exceeded.

Abstract: A hydraulic valve assembly for selectably delivering hydraulic fluid from a supply of hydraulic fluid to one of a first hydraulic operator and a second hydraulic operator is disclosed. The assembly includes first and second supply ports which communicate with the supply and four operator ports. First and third ports communicate with the first hydraulic operator. Second and fourth ports communicate with the fourth hydraulic operator. First and second chambers are provided. The first chamber communicates with the first supply port and first and second operator ports. The second chamber communicates with the second supply port and third and fourth operator ports. Two selection valves operating in unison are each located in each chamber. The selection valves operate between a first position at a first hydraulic fluid pressure and a second position at a second hydraulic fluid pressure.

Abstract: A valve unit having an overridable check valve. On a valve housing a first and a second power connection are provided, which are connected by way of a power duct, on which an overridable check valve is placed, which may be overridden by a fluid control signal, such control signal being able to be supplied to a signal input connection on the valve housing. The valve housing is additionally fitted with a signal output connection communicating with the power duct.

Abstract: A sliding spool valve (1) is provided for controlling flow of fluid especially between an inlet (2) at a relatively high pressure and an outlet (6) at a relatively low pressure. Wherein the spool valve is reciprocally displaced between open and closed positions by hydraulic action of the transmitted fluid.

Abstract: The invention relates to a pneumatic open- and closed-loop control apparatus (10) for flows of pressure fluid, having one inlet conduit (14), two outlet conduits (16, 18), and one venting conduit (20), and also having a valve piston (90) mediating between these conduits and mounted in a valve chamber (92), and to a method for open- and closed-loop control of flows of pressure fluid.

Abstract: A hydraulic valve assembly for selectably delivering hydraulic fluid from a supply of hydraulic fluid to one of a first hydraulic operator and a second hydraulic operator is disclosed. The assembly includes first and second supply ports which communicate with the supply and four operator ports. First and third ports communicate with the first hydraulic operator. Second and fourth ports communicate with the fourth hydraulic operator. First and second chambers are provided. The first chamber communicates with the first supply port and first and second operator ports. The second chamber communicates with the second supply port and third and fourth operator ports. Two selection valves operating in unison are each located in each chamber. The selection valves operate between a first position at a first hydraulic fluid pressure and a second position at a second hydraulic fluid pressure.

Abstract: A valve arrangement including a valve housing (10) which includes an inlet port (11) and two outlet ports (12, 13) for fluid flowing through the housing. A valve element (15) is accommodated in a first valve space in the valve housing and movable between two end positions. The valve element includes two surfaces (16), each of which is adapted for co-action with a respective outlet port such as to close an associated outlet port in one and the other of the end positions of the valve element (15). A device (20 or 21 and 26, 47) for resetting the valve element between the positions. The valve element (15) is mounted on one end of a pivotal arm (18) and has the form of a valve plate or disc which includes valve-element surfaces (16) for alternate co-action with a respective outlet port (12, 13).

Abstract: A valve housing (10) includes an inlet port (11) and two outlet ports (12, 13) for fluid passing through the housing. A valve element (15) accommodated in the valve housing is moveable freely between two end positions and has two surfaces (16) each adapted to close a respective outlet port in one and the other of the two end positions of the valve element. The valve element further includes members (20, 22: 21, 22: 21, 26, 47; 26, 48; 26, 50; 26, 51-54) for resetting between the positions. A double-action pump includes two spaces or rooms that have valve-controlled inlets and outlets (39, 40; 29, 30) for drive fluid and pump-transported working fluid respectively. The spaces are divided into an operating chamber (28) and a working chamber (27) by partition walls (26, 36, 37) which are pistons or diaphragms (26) and reciprocatingly move between end positions.

Abstract: A control valve assembly including a no-bleed pilot valve is disclosed. The pilot valve includes a pressure responsive valve adapted to move in connection with a control parameter, such as downstream fluid pressure. The pressure responsive valve selectively connects certain ports with upper and lower chambers of a control valve actuator so that the upstream and downstream fluid pressures may be used to operate the actuator.

Abstract: In a counter balance valve, a valve body is provided with a valve bore having first and second pump-side ports, first and second motor-side ports and an auxiliary port. A spool is slidably fitted in the valve bore in a longitudinal direction thereof to establish and block communication between the respective ports. Left and right springs maintain the spool at a neutral position in which the respective ports are closed. A left pressure receiving chamber shifts the spool by a pressure oil supplied therein to a first travelling position at which the first pump-side port and the auxiliary port are communicated with each other and the second pump-side port and the second motor-side port are also communicated with each other.

Abstract: The hydraulic control system disclosed herein employs a pair of combination poppet/spool valves to control the operation of a hydraulic cylinder driven from a bidirectional pump. Flow introduced through the source port of one valve lifts the poppet of the other valve on its way to one side of the cylinder which in turn opens a throttling port to modulate return flow from the other side of the cylinder.

Abstract: A communication area of a left pressure reception chamber, a pressure reception chamber, a right pressure reception chamber and another pressure reception chamber for moving a spool to first and second positions with a first pump port and a second pump port is made large at the beginning of a stroke, small at the intermediate of the stroke and medium at the end of the stroke so as to return the spool from the first and second positions to the neutral position in a short time while preventing cavitation from occurring. While the volume of the pressure reception chamber located opposite to the moving direction of the spool is prevented from changing, the spool is moved slowly in the above-described opposite direction. Thus, the spool is prevented from making an over-stroke and also prevented from having a hunching even if a return pressure oil has a large change in pressure.

Abstract: A valve assembly includes a check valve element in the output chamber. The check valve element opens to permit forward flow of fluid under pressure in the output chamber from a source toward a load. The check valve element closes to block back flow of fluid under pressure in the output chamber from the load toward the source. The back flow of fluid under pressure exerts a closing force upon the check valve element from within the output chamber. A counter force generating element is located within the output chamber and coupled to the valve element. The counter force generating element applies a counter force to the check valve element, which urges the valve element toward the opened condition. The counter force is, by purpose, less than the closing force, so the check valve element remains closed.

Abstract: In order to achieve repeatable, consistent operation of a counterbalance valve, a poppet valve element within the valve has a radial bore therein in communication with a control fluid port and an axial bore therein which receives a rod that is anchored to a poppet valve cage that surrounds the poppet valve element. The poppet valve element is urged by a spring into engagement with a valve seat and pilot pressure is applied in opposition to the spring. By virtue of this arrangement, control fluid pressure is applied via the rod directly to the valve body in which the poppet valve element and cage are mounted. By changing the diameter of the rod and axial bore through the poppet valve element which receives the rod, the relief set pressure can easily be changed.

Abstract: For the oscillating triggering of a double acting operating cylinder (4), a reversing valve (6) has been provided and has been inserted between the pressure supply connector (5) and the two operating cylinder drive connectors (2,3) that is driven via two NOT elements (7,8), that each have been assigned to an operating position and connected with a drive connector (2,3). The reversing valve (6) is caused by pressure to periodically switch between the two operating positions. In order to stop oscillating with a defined final position of the operating cylinder (4) or start it up again, at least one of the NOT elements (7) has been provided with a pressure supply connector that can be triggered independently from the supply connector (5).

Abstract: The hydraulic control system disclosed herein employs a pair of combination poppet/spool valves to control the operation of a hydraulic cylinder driven from a bidirectional pump. Flow introduced through the source port of one valve lifts the poppet of the other valve on its way to one side of the cylinder which in turn opens a throttling port to modulate return flow from the other side of the cylinder.

Abstract: A valve includes a distributor with four ports and two positions. In a first position, a first non-return valve allows only circulation of a fluid from the first port toward the third port, while the second port and the fourth port are directly in communication with one another. In a second position, the third port and the fourth port are directly in communication with one another, while a second non-return valve allows only circulation of fluid from the third port and the fourth port in communication toward the first port.

Abstract: The hydraulic counterbalance valve has a valve body with an inlet port, a cylinder port and a pilot port. The valve body has an interior chamber extending through the valve body which forms a check seat where the interior chamber narrows. The interior chamber is in communication with each port by a number of passages. A check valve is disposed in a first passageway between the interior chamber and the inlet port. A bypass passage exists to circumvent the check valve and provide communication between the interior chamber and the inlet port. A control spool is movably disposed in the interior chamber. The control spool has a pilot end, a sealing means, metered groove and a pilot check. The pilot check of the control spool forms a pilot check seal with the check seat of the interior chamber. A spool spring is disposed in the interior chamber and biases the control spool pilot check to seat against the pilot check seat of the interior chamber.

Abstract: A hydraulic fluid-loss control valve for preventing uncontrolled load movement in the event of a fluid loss such as from the bursting of a hose and further for allowing an operator to move the load in a controlled way despite the fluid loss. The control valve is situated between a conventional main spool valve and a piston/cylinder hydraulic actuator which powers the load. The control valve has a spool sliding reciprocally in a bore. Grooves and lands on the spool combine with passages in the control valve body to provide alternate fluid paths between a pump and the actuator and between the actuator and a reservoir. Fluid can flow from a controlled chamber of the actuator only when the spool is in a position which provides a fluid path. A passage within the spool provides fluid communication between an input fluid flow and a chamber at one end of the spool. A second passage within the spool provides fluid communication between an actuator chamber and a chamber at the other end of the spool.

Abstract: A hydromechanical differentiating system for actuator dynamic stiffness enhancement and dynamic load damping. A free floating spool valve receives a pressure signal and moves in opposite directions away from a null position. When the valve moves in response to an increase in the pressure signal it compresses fluid in a chamber connected at the opposite end of the cylinder in which the spool moves and simultaneously connects a source of fluid under pressure to the chamber causing the valve to return to its null position. Conversely, if the pressure signal decreases, the spool valve allows the fluid in the chamber to expand moving the valve away from the chamber and simultaneously connecting system return to the chamber to decrease the fluid pressure in the chamber and cause the valve to return to its null position.

Abstract: A lock valve apparatus and a hydraulic system incorporating a lock valve apparatus including a lock valve body with a bore, a first port, a second port, a third port and a fourth port. There is a spool valve with a valve spool reciprocatingly received in the bore. The spool valve, a first one-way valve and a second one-way valve normally prevent fluid flowing between the ports. The first one-way valve and passageways in the valve permit a fluid flow from the first port to the third port when the first port is pressurized. The second one-way valve and passageways in the spool valve body permit a fluid flow from the second port to the fourth port when the second port is pressurized. The spool valve is shifted to align passageways, including a first annular passageway, between the spool and the bore to permit a return flow of fluid from the fourth port to the second port when the first port is pressurized. The first annular passageway receives pressurized fluid from the fourth port.

Abstract: A pilot control relay valve to change the directional flow of fluid to a piston (such as, for example, the piston of a chemical injection pump for injecting chemicals at a slow or rapid rate over a long period of time), but also allow the recovery of exhaust fluids under significant back pressure. The pilot control relay valve comprises an elongated valve member shiftable within a valve body between a first and second position. The first position allows communication of control fluid to a first pressure receiving surface while allowing exhausting of fluid from a third or opposing pressure receiving surface, thereby to initiate movement of the valve member against the back pressure of the exhaust fluid from its first position to a position equalizing the pressure acting on a second pressure receiving surface with the pressure of the control fluid, thereby causing the valve member to move to its second position.

Abstract: A tilt cylinder for tilting an outboard engine has first and second cylinder chambers. A pair of on/off valves is movably disposed in respective fluid passages connected to a hydraulic pump and the first and second cylinder chambers, respectively. The on/off valves are operatively combined with respective shuttle valves which have respective oil passages in facing relationship to the on/off valves, respectively, and respective ball valve bodies for selectively opening the oil passage into communication with each other. When the hydraulic pump is actuated to develop a working oil pressure buildup, one of the on/off valves is opened by the working oil pressure buildup to establish an oil supply passage from the hydraulic pump to one of the first and second chambers, and the other of the on/off valves is opened by the coacting shuttle valve which is moved by the working oil pressure buildup to establish an oil return passage from the other of the first and second chambers to the hydraulic pump.

Abstract: A lock valve for marine hydraulic steering systems includes a valve body with a spool valve reciprocatingly received in a bore therein. A first port and a second port of the valve are connected to a manual pump. A third port and fourth port are connected to a double acting hydraulic cylinder connected to a rudder or steerable motor. There are valves within the lock valve which normally prevent fluid flowing between the ports so the steering system remains in a fixed position when the helm is released. Fluid can flow from the first port to the third port when the first port is pressurized. A return flow of fluid from the fourth port to the second port is permitted only when the first port is pressurized. When the second port is pressurized, fluid can flow the second port to the fourth port. A return flow of fluid from the third port to the first port is permitted only when the second port is pressurized.