Abstract: A controlling motor for moving a stem along an axis has a hydraulic actuator with a cylinder in which a piston that is frictionally linked to the stem is slidingly and sealingly mounted, as well as a compression spring that is frictionally linked to the stem and acts against the actuator. The controlling motor has a trigger with an inflow area into which hydraulic fluid may be introduced, a pressure area that communicates with the inflow area through a diaphragm and is connected to the actuator, and a drainage area from which the hydraulic fluid may be evacuated without pressure, as well as a switching element that links the pressure area to the drainage area when a positive pressure differential occurs between the pressure area and the inflow area, and that otherwise shuts off the drainage area. The stem may be pushed out of the cylinder by the compression spring and may be drawn into the cylinder when hydraulic fluid is applied to the inflow area.

Abstract: A control system for a press having a clutch and a brake includes a clutch control valve and a brake control valve. The clutch control valve operates the clutch by supplying pressurized air to the clutch. The brake control valve operates the brake by supplying pressurized hydraulic fluid to the brake. The brake control valve is activated by pressurized fluid from the clutch control valve in order to insure simultaneous release of the brake with engagement of the clutch as well as simultaneous application of the brake with disengagement of the clutch.

Abstract: A valve mechanism for use in a hydrostatic transmission including a closed porting system for hydraulic fluid and a sump is provided. The valve mechanism includes a valve body mounted to the hydrostatic transmission whereby the valve body is open to the closed porting system at one end thereof and open to the sump at the other end thereof. The valve body has a first open position whereby hydraulic fluid is pulled into the closed system from the sump when the pressure of the fluid in the closed system is below a first pressure, a second open position whereby hydraulic fluid exists the closed system to the sump when the pressure of the fluid is at a second pressure higher than the first pressure, and a closed position when the pressure of the hydraulic fluid in the closed system is at a third pressure higher than the second pressure.

Abstract: A control means for a hydraulic motor connected to an external load comprises a directional valve (10) for selectively feeding hydraulic fluid to the motor from a pressure source and including load pressure sensing means (24, 25) connected to a load compensating valve (15) located upstream of the directional valve (10) for adjusting automatically the feed pressure in relation to the actual load pressure. The load compensating valve (15) includes a valve spindle (28) with opposite end surfaces (29, 30), one of which is exposed to the load pressure whereas the other is exposed to the feed pressure, and a selectively activatable feed pressure reducing means (38, 43; 50-57) for increasing the bias force acting on the load compensating valve spindle (28) in the closing direction of the latter in relation to the bias force acting in the closing direction of said valve spindle (28).

Abstract: To excavate sticky soil such as clayey soil, left and right buckets of a clamshell bucket are slightly inclined, thereby reducing the force to pull the buckets from a hole. The clamshell bucket includes left and right buckets which are closable, thereby holding soil, and a hydraulic cylinder having a stroke reserve so as to be further extendible after the buckets are closed, whereby the closed buckets can be displaced sidewardly relative to the vertical.

Abstract: An operating valve device for supplying fluid under pressure to an actuator comprises: a first hole (3) and a second hole (4) for allowing fluid under pressure supplied by a pump (P) into an inlet port (2) connected with the pump to selectively flow into pressure chambers (B.sub.1, B.sub.

Abstract: A self-contained rotary actuator assembly has a pump assembly, a precharged hydraulic circuit, and a rotary vane actuator in a single unit. The pump assembly is a bi-directional electric motor driven gerotor pump which is manifolded to a module assembly in which the control elements of the hydraulic circuit are housed. Upon the application of the pressure for driving the rotary actuator in either direction, a pilot operated hydraulic valve is shifted so as to communicate the rotary actuator with the pump. After the pump is turned off, an orifice for the pilot chamber of the valve bleeds the pilot chamber slowly so as to provide a delay in which the rotary actuator holds the convertible top extended or retracted to give the vehicle operator time to latch the top in its closed or open position. In addition, a gas charged precharge chamber in the hydraulic circuit maintains a precharge through a broad range of temperatures.

Abstract: In load sensing systems, pressure compensating valves are normally used to maintain a predetermined pressure differential across the orifices in the directional control valve at a predetermined level. The predetermined pressure level acting across the directional control valve can be adversely affected by flow forces acting on a valving element of the pressure compensating valve. In the subject invention, flow force compensation is provided by having a forced balancing device connected to a pressure compensated valve device so that a force that is directly proportional to the degree of flow forces acting on the pressure compensating valve device is transferred to a valving element thereof in opposition to the flow forces that are acting on the valving element. The subject arrangement is also applicable to providing flow force compensation for negative load pressure compensating valve devices.

Abstract: An internal safety valve for preventing the discharge chute from rapidly falling due a sudden loss of hydraulic fluid pressure. A safety valve assembly for use in a hydraulic cylinder consisting of a safety valve located in the barrel of a hydraulic cylinder. The moveable piston of the hydraulic cylinder has a cavity for receiving the safety valve therein. The safety valve is actuated when the flow leaving the chute lift cylinder exceeds a predetermined flow. The valve immediately stops the hydraulic fluid from leaving the chute lift cylinder maintaining the position of the discharge chute.

Abstract: The present invention comprises a double acting actuator having a piston movable within a cylinder, a main poppet control valve connected to a fluid pressure source, and first and second poppet valves connected in series to a rod side chamber of the cylinder. The piston is extended upon actuation of both first and second poppet valves, while allowing retraction of the piston upon release of either the first or the second poppet valves.

Abstract: A hydraulic system for controlling the contract force of a hydraulic device. A proportional pressure relief valve acts as pilot valve for a main valve that controls the lowering process. The proportional pressure relief valve is provided with a solenoid whose voltage can be varied. A pressure sensing line is also applied to the same side of the valve as the solenoid for biassing the valve against a spring.

Abstract: A pilot operated directional control valve communicates fluid between a hydraulic actuator, a pump and a reservoir. A lockout valve is connected between each main control valve work port and a corresponding cylinder port, and operates to reduce fluid leakage therefrom. Each lockout valve includes a pressure responsive poppet valve member which is exposed to fluid pressure in a lockout chamber. A vent control valve is connected between each lockout valve and a corresponding one of the pilot valves. Each vent control valve includes a vent check valve which controls fluid venting from the lockout chamber and a vent piston which is biased to urge the vent check valve to a closed position thereby trapping fluid in the lockout chamber. When both pilot valves are energized, both lockout valves are vented and a float valve moves to a position wherein both cylinder ports are communicated, via the lockout valves and the float valve, with each other and with the reservoir.

Abstract: An internal check valve for use in a linear hydraulic motor in the form of a piston-cylinder unit including a cylinder body (38) reciprocally slidable on a piston component (40). The piston component (40) includes a tubular piston rod (52) and a piston head (60) defining first and second working chambers (136, 140) within the cylinder body (38). The tubular piston rod (52) includes a center tube (102) located within the piston rod (52). The center tube (102) provides a fluid passageway (134) through its center which communicates with a first working chamber (136). An annular second passageway (142) is formed by and radially between the piston rod (52) and the center tube (102). A spring biased check valve (116) is positioned within the piston rod (52, 54) and is operatively connected with one of the passageways (134, 126, 130). The check valve (116) has a valve member displaceable from a valve seat (120) by hydraulic pressure to overcome the spring bias (122, 124) and allow flow in one direction.

Abstract: An end of stroke cushion for a linear hydraulic motor. A piston-cylinder unit includes a cylinder body (42) reciprocally slidable on a piston rod (40) having a piston head (64) which defines working chambers (82, 84) within the cylinder body (42). The piston rod (62) is tubular and includes a plurality of sidewall ports (P1-P7). A radially-expandable annular valve ring (106) normally snugly surrounds the piston rod (62) and during axial movement of the cylinder body (42) relative to the piston rod (62), the valve ring (106) will move axially relative to the sidewall ports (P1-P7) in the piston rod (62). Pressure introduction to the working chamber (84) through the sidewall ports (P1-P7) of the piston rod (62) and against the valve ring (106) radially expands the valve ring (106).

Abstract: A hydraulic control circuit for uniform controlled movement of stripping and guiding arms in a tree delimbing apparatus. A pair of flow divider combiner valves allow equal amounts of pressurized fluid to communicate with and actuate said cylinders. The piston rods of said cylinders are mechanically coupled to rotate tubular sleeve members with affixed stripping and guide arms between outward and inward positions. The flow divider combiner valves provide equal rates of said fluid to flow to said cylinders to insure said piston rods and mechanically affixed stripping arms and guide arms are moved at equal rates of speed. Thus the stripping levers and guide arms open and close about a felled tree in a uniform manner for delimbing operations.

Abstract: A hydraulic circuit for a swivel working machine, in which the operation of the working unit is speeded up when the swiveling body and the working unit are simultaneously operated, includes, for this purpose, first and second operating valves (15.sub.1 and 15.sub.2) connecting the delivery conduit of a hydraulic pump (10) to a swiveling hydraulic motor (16.sub.1) and to a working unit cylinder (16.sub.2), and pressure compensating valves (18) provided between the first operating valve (15.sub.1) and the swiveling hydraulic motor (16.sub.1) and between the second operating valve (15.sub.2) and the working unit cylinder (16.sub.2), the load pressure of the swiveling hydraulic motor (16.sub.1) and the load pressure of the working unit cylinder (16.sub.

Abstract: In the hydraulic apparatus (1) according to a first aspect of the present invention, mid-pressures between the inlet side and outlet side pressures of a first and a second pressure compensating valves (4, 4') are permitted to act on the flow rate decreasing side pressure receiving surfaces (4b, 4b') thereof through first and second mid-pressure supplying means (13, 13'), thereby restraining operational error and malfunction of the pressure compensating valves (4, 4'). In the hydraulic apparatus (20) according to a second aspect of the present invention. when actuating valves are made to assume neutral position, holding pressures of hydraulic actuators (5, 5') are permitted to act on flow rate decreasing side pressure receiving surfaces (4b, 4b') of pressure compensating valves (4), (4') so that spools of the pressure compensating valves are held at compensating position, thereby improving the response of the hydraulic actuators (5, 5') to lever actuation.

Abstract: The mechanism has an actuator provided with a piston, a servo control valve which is actuated by electric input and output signals for supplying working fluid to the actuator and exhausting working fluid from the actuator, a slider which closes an oil passage from the servo control valve to the actuator and which temporarily engages with the piston of the actuator via a link mechanism, when a system for transmitting the input and output signals or the servo control valve breaks down, and a centering valve which is constructed in one body with the slider and which stops supply and exhaust of working fluid after the actuator has been returned to its neutral position by supply of working fluid to the actuator when a system for transmitting the input and output signals or the servo control valve breaks down.

Abstract: A method and a device for protecting against a press overload is disclosed whereby, when an excessive pressure which exceeds a specified hydraulic pressure is transmitted to a pressure chamber of a press cylinder, this excessive pressure activates the punching of a shear plate by a shear piston and the excessive pressure is released by the shear piston.

Abstract: A hydraulically operated device including a single-acting cylinder having a piston for operating a working tool, a pressure chamber for applying a hydraulic pressure to the piston from an original position to an operated position, and a return spring for biasing the piston toward the original position. The device includes a hydraulic pump for delivering a pressurized fluid to be fed into the pressure chamber of the cylinder, and an automatic drain valve for inhibiting the pressurized fluid from being discharged from the pressure chamber while a difference by which a delivery pressure of the pump is higher than a pressure in the pressure chamber exceeds a predetermined value. When the difference becomes smaller than the predetermined value, the automatic drain valve is operated to allow the pressurized fluid to be discharged from the pressure chamber. Thus, the automatic drain valve automatically drains the pressure chamber when the pump is turned off.

Abstract: An improved pneumatic control system is selectively deactuable and actuable for controlling movement of the armature of a pneumatically-operated device between first and second working positions and includes a timing subsystem that enhances the efficiency of the overall system by stabilizing the control system at a pressure necessary to maintain certain static conditions in the pneumatically-operated device, while still providing for full control air pressure when dynamic operations are required. In addition, such a control system compensates for system leakage in an efficient manner by using full control air pressure only when needed for proper operating functions of the overall system.

Abstract: A valve apparatus (10; 10A) has at least one directional control valve (31; 31A) having a pair of variable restricting sections (43, 44) disposed between a supply passage (35) communicating with a hydraulic fluid supply source (11) and a pair of load passages (36, 37) communicating with an actuator (12). A pressure controller (32) or a pressure compensating valve (32A) is provided for holding a differential pressure across the variable restricting sections at a predetermined value. A detection line (57; 57A) is branched from a first passage (32; 86, 87) located between the pair of variable restricting sections and the pair of load passages for receiving a load pressure produced upon operation of the actuator. A check valve (59) or shuttle valve (90, 91) is provided for selecting a maximum load pressure and a control line (61, 62) introduces the selected maximum load pressure, as a control pressure, to the pressure controller or pressure compensating valve.

Abstract: A safety valve which prevents the discharge chute from rapidly falling due to a sudden loss of hydraulic fluid pressure. The valve is located between the chute lift cylinder port and hydraulic system hose. The valve is actuated when the flow leaving the chute lift cylinder exceeds a predetermined flow. The valve immediately stops the hydraulic fluid from leaving the chute lift cylinder maintaining the position of the discharge chute.

Abstract: A pneumatic percussion tool includes a head valve device including first and second head valves disposed in the body and movable in response to the pressure variation in the head valve chamber. The first and second head valves are positioned at a first position for preventing communication between the main air chamber and the percussion piston chamber while permitting communication between the percussion piston chamber and the outside of the body and preventing communication between the head valve chamber and the outside of the body when the compressed air is introduced into the head valve chamber through the change-over valve.

Abstract: The assembly is composed of a vacuum pneumatic booster (1), a master cylinder (3) and a reservoir (5) of fluid under low pressure which feeds the master cylinder, and is intended to convert a force exerted on a control pedal into a fluid pressure supplying at least one fluid motor. The booster (1) has at least one chamber connected to a vacuum source via a non-return valve (30). This chamber is connected to the source via a duct (21) formed in the master cylinder (3), the non-return valve (30) being arranged at the outlet of the duct (21). The non-return valve (30) is arranged at the end of a pipe (25), the other end of which is connected in a sealed manner to the duct (21), the non-return valve (30) and the pipe (25) being incorporated into the reservoir (5).

Abstract: In a proportional pressure reducing valve including a spool having a first end connected to a solenoid and a second end exposed to a feedback chamber, and formed with a groove for allowing a supply port to communicate with an output port when the spool is driven by the solenoid in proportional to solenoid current under balanced condition of an axial force of the solenoid and feedback pressure, the pressure reducing valve further comprises a valve for allowing the feedback chamber to communicate with a drain port to control the valve into inbalanced condition to momentarily raise output port pressure up to supply pressure, when the hydraulic output pressure within the feedback chamber rises beyond a predetermined relief pressure.

Abstract: In a system for varying the output flow from a constant rate feed pump with low losses by chopping the said output flow into one flow fraction supplied to the load as a power flow and into another flow fraction returned as a pressureless flow, the loads are aperiodically supplied with proportionated amounts of fluid by chopping, the respective amounts of fluid and the chop frequency being inherently controlled in way dependent on the instantaneous requirement of the load in the system. The system for performing the method has a housing with a number of pressure spaces arranged to be acted upon by different flows and with one or more pressureless spaces, a piston with a piston rod arranged in a piston space, a compression spring preferably arranged in a hole in said piston rod and adapted to act against the sum of the hydraulic forces acting on the piston and spool. The method is applicable to complex hydraulic systems and more especially to hydrostatic drives.

Abstract: A distributor for hydraulic cylinders (2), especially applicable to crane drive cylinders, which comprises an axial sliding runner (4) for selection of the oil circuit. Said runner (4) is hollow, forming two separate chambers (19,20) adjacent to the cylinder chamber supply and return ducts with which it is connected through holes in the wall of the said runner. One of the chambers (19) includes means for varying the degree to which the holes are opened, according to the return oil pressure from the cylinder withdrawal chamber. The other chamber (20) incorporates means for opening or closing the connection through it, according to the pressure being delivered by the pump, to the cylinder withdrawal chamber oil supply duct. Thus it is possible to regulate the flow as an inverse function of the load and to reduce the effect of induced pressure.

Abstract: A regulator arrangement (14) for a servo system (10) having a first stage valve spool piston (44) for developing a primary operational fluid (P.sub.c) and a second stage valve spool piston (70) for developing secondary operational fluid P.sub.cr having a constant fluid pressure. A control valve (109) selectively connects a first chamber (100) of a cylinder housing bore to either the primary operational fluid pressure P.sub.c or a reference fluid pressure P.sub.B to develop a fluid pressure P.sub.x in first chamber (100) while a second chamber (102) is connected to the secondary operational fluid (P.sub.cr). A load piston (96) responds to a pressure differential (P.sub.x -P.sub.cr) by moving to either expand or contract the second chamber (102) and produce a fluid pressure (P.sub.crx) in the secondary operational fluid. The fluid pressure P.sub.crx is communicated to the second valve piston (70) to correspondingly allow either additional primary fluid (P.sub.

Abstract: In a pneumatic ram boring machine for laying pipelines without trenching, which is connected to a source of compressed air by a hose, a valve that suddenly opens automatically at a predetermined pressure is arranged upstream of the striker piston. On opening the valve a pressure wave results which reaches the impact piston almost undamped and prevents it from stopping at a dead center position and not starting.

Abstract: A fluid pressure actuated assembly includes a casing made of a flexible resilient material, such as rubber or polyurethane, a coiled tension spring sleeved on the casing for biasing the casing to move toward a retracted position, and a coiled spacing spring interposed between the tension spring and the casing for preventing any wall of the casing from being clamped between any two adjacent turns of the tension spring. When a compressed fluid is applied to the interior of the casing, the casing extends.

Abstract: The device comprises a pilot slide (27) controlled by a pressure differential (P-P') determined by an electromagnetic pilot valve element (43) located in a return circuit to a tank (7) which is common to both the hydraulic installation and a branch pipe (8). The device preferably includes an isolating valve (40) connected to the pilot valve element (43) so as to isolate a pilot chamber (30) in the event of a failure of the electromagnetic actuator.

Abstract: A fluid flow control valve in a fluid flow control circuit comprises a cavity, first, second and third ports open to the cavity, and a valve member for selectively closing the first port or the second port. The third port serves as an input for receiving fluid under pressure and the other two ports serve as to outputs for this fluid each extending to an associated outlet. A solenoid causes an armature to rotate about a lining so that a lever on the armature is arranged for selectively opening and closing the outlets to close the output associated with this outlet. The valve member is responsive to pressure drop at one or other of the outlets to close the output associated with this outlet. Downstream of the valve there are ducts extend from between the input and each of the outlets for supplying fluid received from the input.

Abstract: A work cylinder having an internally-disposed, automatically-operated drain valve disposed in one or both ends of a housing having a cylinder bore formed therein. A reciprocally-movable piston divides the bore into first and second pressure chambers. A drain chamber formed in one or both ends has a movable plunger member disposed therein. A first passageway allows fluid from the pressure chamber to act on one surface of the plunger. A pilot valve is partially formed on a bottom portion of the plunger and opens when fluid pressure is exhausted from the adjacent pressure chamber. A bias spring acts on the plunger to prevent closing of the drain valve upon initial pressurization of the adjacent chamber. This initial pressurization assists in purging additional moisture from the chamber until a threshold level is exceeded to close the drain valve.

Abstract: The invention relates to hydrostatic steering control apparatus of the type having a hydrostatic steering motor which is connected to wheels to be steered and a steering wheel controlled metering or quantity setting device for controlling the hydraulic fluid supplied to the steering motor. A hydraulic amplifier connected to the steering motor has the characteristics of generating and transmitting undesired pressure pulses to the steering motor during steering switching operations. One way pre-stressed check valves are disposed respectively between the quantity setting apparatus motor ports and the steering motor ports. The check valves open in the direction of the steering motor ports and operate to allow bypassing the amplifier during the steering switching operations.

Abstract: A modulator assembly is interposed in a fluid circuit between a source (S) and a user device (U), said assembly being composed of a metering electrovalve (E) forming a first restriction (.sigma.1) in the fluid circuit, a pressure regulation valve (R), loaded by a spring (22), being subjected to the pressure of fluid delivered by the metering electrovalve to the user device and forming a second variable restriction (.sigma.2) between the outlet of the electrovalve (E) and a tank (33). The pressure regulation valve (R) is integrated into the metering slide (14) of the electrovalve.

Abstract: A signal valve (38) is connected to a supply conduit (16) connecting a pump (11) with a control valve (14) for transmitting an artificial load signal to a load signal chamber (34) of a pressure compensated unloader valve (27) when the control valve is at an operating position and the pressure in the supply conduit (16) is below a preselected value. This moves a valve member (31) of the unloader valve (27) to a blocking position causing essentially full pump flow to be directed to the hydraulic jack for decreasing the response time in situations wherein the hydraulic jack has cavitated and no positive load pressure signal is present.

Abstract: A fluid pressure system incorporating a piston and cylinder actuator which is initially moved from right to left and is reversed at the left hand end of its stroke by a switching valve upon receiving a signal through a passage from a sensing valve which becomes hydraulically balanced during a no-flow condition of the system and is displaceable to a switch initiating state during that condition by a small force originating from a light spring, or the actuator or from the operation of another valve in the system.

Abstract: A control valve for limiting the flow rate of a fluidized medium to a hydraulic motor during start up of the motor so as not to induce loads which exceed predetermined torque limits of apparatus driven by the motor. The control valve includes a poppet which is spring biased to a seated closed position. Increasing inlet-to-outlet pressure differential unseats the poppet in a downstream direction uncovering bypass ports which allow an initial surge of fluid to the motor to accelerate the motor to a predetermined speed at a rate which does not exceed the torque limits. Further downstream movement of the poppet exposes greater cross-sectional areas of main inlet ports which permit additional modulated fluid flow to accelerate the motor to its operational speed. The rate of movement of the poppet in the downstream direction is limited by flow restrictor orifices which conduct fluid which is displaced from a chamber due to the downstream movement of the poppet.

Abstract: In the hydraulic system disclosed herein, a flow matching device is employed to implement a system in which filling, emptying and holding of a variable volume load, such as a hydraulic piston, may be accomplished at controlled flow rate by a hydraulic circuit including a flow matching control valve.

Abstract: A system for actuating a clutch by axial movement of an actuating member which is rotatable about a clutch axis with the axial movement for actuating occurring via engagement of the actuating member with a clutch release bearing, the system including a fluid actuated clutch release bearing assembly actuable along a central axis which is generally in line with the clutch axis, and with the clutch release bearing assembly including alignment means separate from the clutch release bearing for moving the axis of rotation of the clutch release bearing substantially into alignment with the clutch axis and with the clutch release bearing assembly including a housing member having an annular, axially extending cylinder portion having a cylinder cavity adapted to receive a piston for reciprocation therein, the cylinder portion being integral with the remainder of the cylinder housing whereby the need for a seal between the cylinder portion and the connecting portions of the cylinder housing is obviated and with the sy

Abstract: A hydraulic circuit is disclosed for activating a clutch as well as a throttle valve which is used in the circuit. The hydraulic circuit includes a hydraulic actuator which is connected to a source of pressurized fluid to alternatively activate the clutch. Connected between the source of pressurized fluid in the actuator is a control valve and a pressure-responsive throttle valve. The control valve is basically an on/off valve which controls the flow of fluid to the clutch actuator or from the clutch actuator to a reservoir. The throttle valve, on the other hand, is arranged in series with the control valve and is responsive to fluid pressure on its downstream side to cause increased throttling of the fluid as the fluid pressure to the actuator increases. Such a circuit is beneficial in preventing the clutch from snatching as it is being engaged.

Abstract: A spool valve for use in a hydraulic ram includes a piston journalled for axial movement within a cylinder under the influence of a fluid fed under pressure to the cylinder. The spool valve is journalled within a valve block closing an end of the cylinder through which passes a piston rod. The valve is biased from one position to another by means of differential areas of a circumferential groove around the spool and by applying fluid to a chamber at one end of the spool.

Abstract: A counterbalance valve connects a source of hydraulic fluid to a power piston-cylinder unit for positioning and/or holding a load such as a pivoted bucket arm of earth moving equipment. A directional control valve is operable to reverse the supply connection to the cylinder unit and to operatively close the connections thereto to hydraulically lock the cylinder unit and attached load in place, with a highly restrictive bleed passageway. The counterbalance valve has a first valved passageway between a pair of ports which includes a check valve to provide one directional flow between the two ports. A dual poppet valve unit includes a pair of parallel passageways in parallel with each other and with the first passageway. The double poppet valve includes a main poppet valve having a valve stem with a piston head and a spaced member of a larger effective area.

Abstract: An hydraulic system: a power assisted vehicle steering system which includes such an hydraulic system and a method of alleviating noise in an hydraulic system. The hydraulic system as applied to a vehicle steering gear (1) has an open center valve (3) which directs hydraulic fluid under pressure derived from a pump (12) and in response to a steering maneuver through a shaft (4) to a servo motor of the gear (1). Downstream of the open center valve (3) is a restrictor (8) through which hydraulic fluid from the valve (3) passes to a reservoir (11). The restriction effected by the restrictor (8) to fluid flow from the valve (3) to the reservoir is variable to provide a throttling action and a back pressure in the line (6) to alleviate noise in the valve (3).

Abstract: A venting valve comprising a body having first and second ports. A movable valve member having a venting passage is located in the body and is biassed to a first position where the venting passage provides communication between the first and second ports. A chamber is located within said body and a third port opens into the chamber. The construction and arrangement is such that the introduction of sub-atmospheric pressure into the chamber via the third port causes the valve member to move to a second position where the first port is isolated from the second port but is opened to the third port via the chamber.

Abstract: A device for connecting a hydraulic pump or other pressure fluid source to a working cylinder or other fluid motor comprises a pair of concentric hoses and a safety shut-off valve. One end of the inner hose is connected to the cylinder and the other end is connected to the pump by way of the safety shut-off valve. The space between the hoses normally is unpressurized and is in constant communication with a cavity containing a movable element of the shut-off valve. An elevated pressure in the space between the hoses will actuate the valve element for closing the shut-off valve. A second valve element is movable to close the valve when subjected to fluid flow forces resulting from an excessive flow of hydraulic liquid through the shut-off valve.

Abstract: A valve for automatically dumping a load of solids entrained within a fluid transport medium in response to flow interruption is disclosed. The automatic dump valve is particularly well-suited for use in combination with a nodule transport riser in deep ocean mining operations. The automatic dump valve system is combined with a tubular conduit defining a longitudinally extending flow passage having a sidewall opening defining a dump port. The automatic dump valve assembly includes a movable dump port cover plate and a hydraulic actuator coupled to the cover plate. The hydraulic actuator is operably responsive to pressure changes within the flow passage relative to the pressure exerted by a surrounding body of water to open and close the dump port.

Abstract: A hose with a one-way valve used in a brake actuating system for automobiles. A one-way valve unit is housed in a flexible hose for connecting a booster shell of a servomotor with an intake manifold of the internal combustion engine so as to prevent leakage of vacuum. A valve housing receives therein a valve member and a valve spring thereby forming the one-way valve unit. The housing further has a valve seat, a cylindrical guide portion and an annular seal projection of diameter larger than the guide portion. A fastening band is provided on the outer periphery of the hose to prevent movement of the one-way valve and is marked with a mounting direction of the hose.

Abstract: A hydraulic circuit is disclosed for activating a clutch as well as a throttle valve which is used in the circuit. The hydraulic circuit includes a hydraulic actuator which is connected to a source of pressurized fluid to alternatively activate the clutch. Connected between the source of pressurized fluid in the actuator is a control valve and a pressure-responsive throttle valve. The control valve is basically an on/off valve which controls the flow of fluid to the clutch actuator or from the clutch actuator to a reservoir. The throttle valve, on the other hand, is arranged in series with the control valve and is responsive to fluid pressure on its downstream side to cause increased throttling of the fluid as the fluid pressure to the actuator increases. Such a circuit is beneficial in preventing the clutch from snatching as it is being engaged.