Abstract: A return to dig system for a work machine having at least one implement is actuated by a hydraulic cylinder using a switch, such as with a push button, to control a valve and solenoid to move the implement from a remote position to a preselected position, usually the starting position. The preselected position is determined by a sensor and a detectable element, such as a magnet. The location of the detectable element may be adjusted to provide a plurality of preselected positions. When the detectable element is sensed, the solenoid is repositioned to stop movement of the implement. The push button is located on a device that controls the movement of the implement and various other functions of the work machine. The actuation of the return to dig system by the push button does not affect any other unrelated function of the work machine controlled by the device.

Abstract: An implement draft tongue is moved through a range of working positions to a transport position extending transverse to the working direction of the implement by an extensible and retractable hydraulic actuator. A control for the hydraulic cylinder includes an interrupter valve that is actuated, in response to a preselected extension of the hydraulic cylinder so as to prevent the cylinder from extending beyond a position for moving the draft tongue to one extreme of its operating range, when an actuating device for the interrupt valve is enabled. When the actuating device for the interrupt valve is disabled, the hydraulic actuator may be extended fully to place the draft tongue in its transport position.

Abstract: A fluid-operated circuit for setting the top dead center and the bottom dead center of the punch actuation cylinder in punching machines comprises a first copying distributor which distributes pressurized fluid, which has a spool at one end and can be connected in output to the upper section of the chamber in which the actuation cylinder slides and in input to a first pump for feeding low-pressure fluid and to at least one first fast-acting electric valve element; the spool can be pushed into position by contact by a corresponding setting element with continuous micrometric movement.

Abstract: The invention relates to a shockproof hydraulic cylinder that has a cylinder housing (1), in which a plunger (4) that is driven via a plunger shaft (10) is arranged to move axially, and optionally a hollow-cylinder damping plunger (11). Using different embodiments, an end-position damping is carried out on one or both sides. Plunger shaft (10), plunger (4) and damping plunger (11) can be designed in a hollow-cylinder form.

Abstract: A fluid controlled switching unit includes a valve block; a guide bore provided in the valve block; first and second work chambers provided in the valve block and spaced from one another; first and second cylinder bores provided in the valve body; and a plunger rod guided in the guide bore for reciprocating motion therein along a displacement path. The plunger rod has first and second piston faces situated in the first and second work chambers, respectively, and exposed to fluid pressure prevailing therein. The first and second piston faces move in the first and second cylinder bores, respectively. A valve body is attached to the plunger rod for forming a unitary structure therewith. The valve body has opposite pressure faces as well as first and second opposite end positions determining opposite ends of the displacement path. The valve body, when situated in one of the end positions, is exposed solely unilaterally to fluid pressure at one of the pressure faces thereof.

Abstract: The present invention relates to a sprayer boom lock valve for automating the setup sequence for sprayer operation from the transport position. The lock valve comprises a lever, spring biased toward a valve closing pin, and a cam secured on the secondary boom of the sprayer boom. When the secondary boom is rotated to release wheel locks in the setup sequence, the cam releases the lever which acts on the valve closing pin to close the valve and prevent any further rotation of the secondary boom. The valve is opened again by a linkage which is pulled tight when the sprayer wings are opened, retracting the lever and opening the valve. The hydraulic drive line is then reestablished to complete rotation of the secondary booms.

Abstract: For a hydraulic rack-and-pinion steering assembly for which a working piston is guided in a hydraulic cylinder which features an end limit stop by which, in an end position of the working piston, a path for the pressure agent supplied to the working piston by drill holes for the pressure agent is formed from the working space under pressure to a space of less pressure, in order to improve the hydraulic rack-and-pinion steering assembly such that it is simple to manufacture at limited cost, a rack-and-pinion steering assembly is improved by having, in the region of each pressure supply drill hole, at least one drill hole which can be executed and sealed from the housing exterior and which can be connected by means of a connecting line to the respective pressure supply.

Abstract: In hydraulic heavy equipment, a working device has a boom, an arm and a bucket. An operating device has the same link structure as in the working device. By operating the working device, control valves are operated and the working device functions in a similar manner to the operating device. The movement of the working device is transmitted, and the control valves are brought back to the neutral position. Therefore, the working device follows up the operating device, and functions in the same manner as the operating device.

Abstract: The invention relates to a freely activatable hydraulic valve control device for a stroke valve, which valve control device is arranged particularly in an internal-combustion engine. The stroke valve includes a valve stem and a first spring acting on the valve stem in the valve-closing direction as well as a second spring acting at least periodically on the valve stem in the valve-opening direction. The valve stem is connected at least to a control piston arranged in a working space and capable of being loaded on two sides with a working fluid. The pressure of the working fluid in the working space can be regulated via a pressure source together with a switching valve and a supply conduit.

Abstract: A hydraulic system having a high-pressure differential cylinder implemented as a servo actuator is hydraulically connected to a valve combination and an electro-hydraulic servo valve. The valve combination is a multi-functional valve including multiple interengaging valves and correcting elements all disposed within a housing. The valves and correcting elements are positioned and engaged along a functional axis of the multi-functional valve. This combination of valves provides for a single lightweight housing for the valve. The multi-functional valve is hydraulically connected via conduits with the servo valve and the differential cylinder. This device allows for the use of a single valve arrangement for controlling the numerous operating modes of the differential cylinder or servo actuator.

Abstract: A fluid power apparatus is connected to a pressurized fluid supply and a conventional helm pump controlled by the helm of a vessel to shift the rudder. The apparatus comprises an actuator cylinder connectable to the rudder, and a servo cylinder and a main valve connected to the helm pump to pass fluid therebetween and between the actuator cylinder. The actuator cylinder and servo cylinder have respective bodies and piston rods, and portions of the servo cylinder and actuator cylinder are connected together for concurrent simultaneous movement along respective longitudinal axes. Valve shifting structure is responsive to a change in fluid signal from the helm pump applied to the servo apparatus. Fluid diverting structure is responsive to a threshold supply pressure so as to actuate the valve to stop flow of supply fluid when supply pressure drops below the threshold pressure.

Abstract: A method for locking a hydraulic actuator in a predetermined position and a locking hydraulic actuator are provided. The method includes the steps of supplying hydraulic fluid to a forward chamber in the hydraulic actuator, transferring the hydraulic fluid from the forward chamber into a forward moiety of the rearward chamber in the hydraulic actuator, and sealing the hydraulic fluid in the forward moiety of the rearward chamber to accomplish the locking function. Conversely, the actuator lock is released by the application of fluid supply pressure to the rearward variable chamber.

Abstract: A fluid pressure operated piston engine assembly, such as a pump assembly, including a fluid pressure operated piston engine and a fluid valve for coupling fluid under pressure to alternative portions of the piston chamber of the piston engine. The fluid valve includes a valve spool which is translated to effect the alternative modes of coupling pressurized fluid to the piston chamber. The translation is accomplished by a shifter assembly having a shifter rod attached to the valve spool. The shifter rod includes a pair of diametrically opposed magnets attached thereto. A fork is attached to the piston engine drive shaft at one end and is mounted for limited movement along the shifter rod between the pair of magnets of the shifter rod.

Abstract: A hydraulic control system for controlling an actuator has a cylinder and a piston, and an oil pump. A first passage is communicated with the oil pump, and a second passage is communicated with the cylinder of the actuator. A plurality of branch passages are connected in parallel between the first and second passages, and a valve is provided in each branch passage. The hydraulic control system has a flow rate setting device for operating each valve thereby applying a predetermined quantity of oil to the cylinder of the actuator to shift the piston a desired distance.

Abstract: A cylinder apparatus capable of effectively restraining a loss of energy with a simple structure at a low cost. When a piston 16 of a main cylinder 11 cuts off a communication between a subchamber 20 and a supply/exhaust passage 32, a pressure of the subchamber 20 is pushed by the piston 16 and thereby increased. However, an exhaust fluid from the subchamber 20 having the increased pressure is fed to a subcylinder 62. A piston 48 is moved while controlling a velocity by a flow rate control valve 70 in synchronization with the piston 16. This arrangement eliminates a necessity for a special position detector, etc.. The structure is therefore simplified, and the cost decreases. Simultaneously, the energy can be effectively utilized because of employing the exhaust fluid.

Abstract: A force limiter for limiting the force with which two articles come into contact with each other, which force limiter comprises a control member (11) displaceable with respect to a holder (5), which member is pneumatically prestressed with a force which is substantially independent of the relative position between the holder (5) and the control member (11). The force limiter can be used in devices in which, after stopping a drive the contact force between the driven first article and the second article in contact therewith mustnot exceed a given threshold value. More particularly the use in ultrasonic deformation devices is considered.

Abstract: A fluid power apparatus is connected to a pressurized fluid supply and a conventional helm pump controlled by the helm of a vessel to shift the rudder. The apparatus comprises an actuator cylinder connectable to the rudder, and a servo cylinder and a main valve connected to the helm pump to pass fluid therebetween and between the actuator cylinder. The actuator cylinder and servo cylinder have respective bodies and piston rods, and portions of the servo cylinder and actuator cylinder are connected together for concurrent simultaneous movement along respective longitudinal axes. Valve shifting structure is responsive to a change in fluid signal from the helm pump applied to the servo apparatus. Fluid diverting structure is responsive to a threshold supply pressure so as to actuate the valve to stop flow of supply fluid when supply pressure drops below the threshold pressure.

Abstract: A drive system for a lid or a flap of a convertible car body in which the control effort for the drive system is reduced by configuring the working cylinder as a control valve which releases the lid or the like after unlocking of the lock for lifting by the lifting cylinder, and is connected between the control device and the lifting cylinder.

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 service machine stopping apparatus is provided for a midget rotary power shovel wherein an upper rotary member is rotatably disposed on a lower travelling member capable of self-travelling and a service machine is mounted onto the upper rotary member. The stopping apparatus comprises operation valves for controlling each of a boom cylinder, an arm cylinder and an offset cylinder. Solenoid valves disposed in tubing connecting each operation valve with each cylinder are switched from a communication position to a cut-off position when the service machine reaches a critical region of space, and check valves for check the flow in the cylinder direction when in the cut-off position.

Abstract: An actuating assembly having a cylinder which receives a plunger defining a fluid restricting means along its lower end. A feed conduit delivers pressurized fluid through a fluid inlet and into the cylinder, which displaces the plunger out of the cylinder. As the plunger is displaced, the fluid restricting means progressively covers the fluid inlet, progressively restricting the rate of fluid flow into the cylinder, and slowing the plunger's displacement.

Abstract: A clamping mechanism which includes a cylinder and a piston. The diameter of the piston is less than the internal diameter of a rear chamber of the cylinder such that fluid flows around the piston when the piston moves from an open position to an intermediate position. The diameter of the piston is equal to the internal diameter of a front chamber of the piston such that fluid cannot flow around the piston when the piston moves from the intermediate position to a closed position. To prevent cavitation within the cylinder, fluid is charged to the cylinder in accordance with the movement of the piston.

Abstract: A hydraulic drive mechanism for a punching or an embossing tool, with a double-acting drive hydrocylinder with differently large piston areas, the rapid feed operation, the working feed operation, as well as the rapid retraction operation being controllable by the joint or alternative pressurization of these piston areas. For effecting switchover, an area switching valve is provided which switches over, once the driving pressure exceeds, for example, 90% of the maximum initial pressure of the pressure supply unit, from differential operation to unilateral pressurization of the larger drive area. The area switching valve comprises a check valve acted upon, in the opening direction, by the operating pressure in the smaller driving pressure chamber. A locking spring force of the check valve is equivalent to an opening pressure of about 90% of the supply pressure.

Abstract: The present invention is directed to a hydraulic percussive machine with a shuttle valve to control the flow of fluid to and from a drive chamber without timing lands on the piston and a seal between the drive and return chambers. This is made possible by the use of a restrictive orifice connected to the shuttle valve and the port in the return chamber which is covered and uncovered by the piston. When the port is uncovered, the shuttle valve moves over under pressure. When the port is covered, pressure leaks away to the orifice so that the shuttle valve moves back again.

Abstract: Small-sized engine operated by an expanding gaseous fluid, which comprises a cylinder (18), a piston (20) and an inlet valve (38), the upper parts of the cylinder (18) and the piston (20) cooperating momentarily with a perforated (29) resilient membrane (28) circumferentially secured to the cylinder (18) and performing the functions of a pneumatic seal temporarily.

Abstract: In percussion drilling such as earth drilling, a hammer piston driven by pressure medium is axially reciprocally movable in a drill body to transfer impact energy to a drill shank connectable to a drill bit. The axial position of the drill shank in the drill body is monitored, and the impact energy of the hammer piston is varied as a function of said position. For this purpose a sensor in the drill body produces a signal corresponding to the axial position of the drill shank in the drill body. By means of a control valve, the signal is used to control the pressure of the pressure medium actuating the hammer piston, thereby varying the impact energy.

Abstract: A shift lever and throttle lever coaxially mounted on the casing of an automatic transmission are engaged, respectively, by a lever mounted on each of two concentric shafts whose axes are aligned with the axis of the transmission levers. The shafts have torque sensors located between the levers carried by the shafts and bearings that support the shafts in rotation. The outer shaft has a radial positioning actuator which is hydraulically driven from a source of hydraulic pressure through a servo controlled valve that selectively opens and closes hydraulic passages. The actuator includes a vane fixed to the shaft and a stator that divides a cavity into two halves, each of which is pressurized selectively by operation of the servo.

Abstract: An electropneumatic door control for vehicles is disclosed which consists of a pneumatic portion and an electronic portion. The electronic portion processes successive commands actuated by the vehicle operator to channel the signals to the pneumatic portion of the apparatus to activate alternate door openings and closings. Any blockage of the door movement is detected and signals processed to reverse the door closing or to halt the opening until the fault is corrected. The electronic portion also assures that the vehicle doors can only be opened after the vehicle has come to a stop, that when the vehicle doors are open the station or parking brake is held engaged, and that an audible warning signal sounds for a predetermined interval before the closing of the door.

Abstract: A vacuum responsive switch for detecting a failure in creation of a control vacuum within the control diaphragm chamber. A solenoid valve is provided which functions to equalize pressure within one of a power diaphragm chamber and a leak chamber with the other when vacuum represented by a signal from the vacuum responsive switch is lower than a predetermined value.

Abstract: A hydraulically-operated breaking device of this invention uses a hydraulically-operated differential piston for driving an electric circuit switching unit, and making and breaking pilot valves for actuating the differential piston. In this device, a control valve operated by the action of the pilot valves includes two poppet valves, and drives an intermediate valve which drives the differential piston. Further, the control valve can perform a quick operation at breaking, and can accomplish a given operation even with use of impulse command signals to operate the pilot valves or even in case of a liquid pressure drop during the operation. Furthermore, the use of an auxiliary valve and an auxiliary switch provides the device with a simultaneous action preventive function, pumping action preventive function, and breaking operation preference function.

Abstract: This invention relates to direct acting rotary actuator cylinders wherein the linear motion of the piston is directly converted to angular motion by a means completely enclosed within the cylinder, which means comprises a slidable partitioning body engaging the circular cylindrical cavity in the cylinder in an air-tight sliding relationship and a circular cylindrical rod coaxially and rotatably disposed in said circular cylindrical cavity having a mid-section with a noncircular cross section of a diametrical dimension greater than the diameter of said circular cylindrical rod.

Abstract: An electro-pneumatic door control apparatus for use on public vehicles and including reversing mechanism for changing the direction of door movement, either automatically or operator-initiated, in the event of an obstruction in the door. The control apparatus further includes a flip-flop for recording the position (either open or closed) of the door at all times, a monitoring logic device for recognizing the position of the flip-flop and what type of monitoring function is permitted, a control logic device for picking up the door command and the signal from the monitoring logic device combing them and transmitting them to a valve solenoid control device for energizing respective solenoids of several valve devices by which the appropriate movement of the doors is effected.

Abstract: An active, mechanical hydraulic control device for vehicles including watercraft and aircraft, comprises an acceleration pick-up having a relatively small mass. Movements of the mass are sensed by a nozzle and deflection plate system which controls as a preamplifier the displacement of a power drive member provided with one or more control apertures, the flow cross-sectional areas of which depend on the instantaneous position of a piston to which the power drive member is connected. The movements of the mass vary the gap width between the nozzle or nozzles and the deflection plate forming part of the movable mass. The change in the gap width controls the adjustment or displacement of the power drive member through a follower amplifier formed by the piston. The central or balanced position of the piston is assured by the control apertures forming respective piston position responsive valves.

Abstract: Cylinder/piston drive especially for re-tightening systems in automatic safety belt winding devices, with a cylinder in which a drive piston is movably guided, as well as with a pressure accumulator which can be connected to the interior of the cylinder. The drive piston 13 has in the region facing the connecting point of the pressure accumulator (cartridge 34) at least one reduced cross sectional pressure surface (annular 15, 27) and operates with a guide part (10,21) in the cylinder 1 conforming to the reduced cross sectional shape of the drive piston such that at the beginning of the pressure action, only part of the cross section of the piston is exposed to the pressure force.

Abstract: A valve for controlling the admission of gas to a cylinder of a piston-type machine, or for the discharge of gas therefrom, comprises a magnetic armature shiftable between a pair of magnetic poles formed to receive the armature with minimal radial play and with a predetermined air gap from the attracting pole in the energized condition of the coil. The energizing circuit includes an inductive proximity switch which is triggered without engagement by a metal formation on the crankshaft and applies its signal to a pulse former generating a steep-flank pulse triggering a timer to produce two rectangular voltage pulses of different durations. These pulses are applied to a gating circuit which produces a stepped signal with a high initial amplitude which is amplified and applied to a power converter energizing the coil with a corresponding current waveform. A monitoring circuit responds to deenergizing the coil to drain residual magnetism from the pole piece to enable a spring to rapidly close the valve.

Abstract: Linkages connected to the axles of a single or twin axle dump vehicle open a control valve mounted on the vehicle frame to divert hydraulic fluid from the lift cylinder to the hydraulic reservoir when the frame tilts laterally a preset amount relative to the axles.

Abstract: A cylinder control device of a hydraulic cylinder apparatus including a two-position, directional control valve having a pilot chamber for effecting control of reversal of the direction of movement of a piston, and a control valve movable between two positions depending on the pressure of working fluid in a conduit on the pump side. The control valve is mounted in a passage connecting the pilot chamber of the two-position, directional control valve to a valve means capable of bringing the pilot chamber into communication with conduit on the fluid discharging tank side when the cylinder piston reaches a predetermined position in its rearward stroke. Alternatively, the control valve may be mounted in a passage connecting the pilot chamber of the two-position, directional control valve to another valve means capable of bringing the pilot chamber into communication with the conduit on the pump side when the cylinder piston reaches the end of its forward stroke.

Abstract: A warning system for pneumatic fastener driving tools that acceptable bumper deterioration has been exceeded thereby to warn against further use of a tool prior to replacement of the bumper. A piston carrying a driver blade moves from an upper position of rest to lower fastener driven positions. The piston sealingly engages the cylinder wall via a sealing ring. As the bumper deteriorates, the piston moves to lower and lower fastener driven positions. When the piston reaches a predetermined lower position, the effectiveness of the sealing ring is impaired, as by engagement with a notch or edge which tends to destroy or dislodge the sealing ring. This allows high pressure air to escape past the sealing ring to signal that the bumper should be replaced, as by seriously reducing the effectiveness or operability of the tool or as by producing an audible signal by the escaping high pressure air, or both.

Abstract: A servo controlled, proportional valve is connected in parallel with a forklift truck control valve to regulate the speed at which the fork is raised or lowered by shunting the forklift pump output to the hydraulic fluid reservoir during the raising of the fork and by restricting the return flow of fluid from the lift jack during lowering of the fork with the setting of the proportional control valve being servo controlled in response to a fork height sensor.

Abstract: Hydraulic control apparatus for controlling the rate of flow of a fluent plastic from an injection nozzle of an injection molding machine wherein an injection ram is connected to a hydraulic piston in a hydraulic cylinder. The control apparatus controls the pressure exerted by a hydraulic fluid in the cylinder by means of a main hydraulic circuit including the cylinder, a valve and a pump connected in series and a main line pressure valve connecting in parallel a plurality of pilot pressure control valves having different pressure set points to the main line. The pilot pressure control valves are operated in sequence by an electrical relay and timer circuit, or a combination of such circuit and limit switches.

Abstract: In a die cast machine of the type wherein the piston of an injection cylinder is advanced by pressure gas admitted into the rear chamber of the cylinder while discharging pressurized liquid in the fore chamber, and the piston is retracted by pressurized liquid admitted into the fore chamber while forcing the gas in the rear chamber back into a gas accumulator, a control valve device is provided in the path of the pressurized liquid discharged from the fore chamber, and the control valve device is controlled so as to vary the flow quantity of the discharged pressurized liquid in accordance with the position of the piston during its forward movement. There are also provided two gas accumulators which are connected to the rear chamber of the cylinder through a valve device which is controlled so as to adjust the rate of increase of the pressure applied to the molten metal at the final stage of the injection casting operation.

Abstract: A combustion engine is provided comprising a housing; a cylinder defined within the housing and a piston disposed for movement within the cylinder. A heating chamber is also defined within the housing separated from the cylinder. The heating chamber includes a fuel inlet and fuel igniting means. A passageway extends between the heating chamber and cylinder and means disposed for movement with the piston is provided for covering and uncovering the passageway during selective portions of the engine cycle to provide a flow path from the heating chamber to the cylinder.

Abstract: An intensifier unit includes a pair of sequentially operated reciprocating ram assemblies, each powered by a cylinder motor. Extension of the cylinder rods is accomplished by application of pressurized hydraulic fluid to the pistons. The pistons are returned quicker than they are extended by means of continuous application of pressurized air to the back side of the pistons. The cylinder motors are precompressed prior to their respective forward strokes by means of an accumulator which continuously bleeds from the main hydraulic fluid supply line. Circuitry is provided to insure that precompression continues even if the ram and its driving piston move from their retracted position. Also disclosed is a safety interlock to shut down the intensifier if both cylinder rods become accidentally simultaneously extended.

Abstract: A pneumatic actuator having a double-acting piston separating two pressure chambers, spring means to urge the piston in one direction; and valve means adapted to admit compressed air to one of the chambers and thus to load the spring means, then to transfer some of said air into the other of the chambers at a selected phase-position of said piston, and then to open the one chamber to atmosphere so that the combined forces of the spring means and of the compressed air acting on the piston in said other chamber complete the power stroke of the actuator.

Abstract: Multiple embodiments of a hydraulic control circuit for a double-acting hydraulic motor to provide fluid at a relatively high pressure for operating the motor in a selected direction and otherwise providing operating fluid to the motor at a relatively low pressure, the control circuit including a dual pressure relief valve which is operatively responsive to the motor or an implement positioned by the motor to provide the two operating pressures. An additional dual pressure relief valve regulates the flow of exhaust fluid from one side of the motor to allow controlled response of the motor to external forces. The hydraulic control circuit of the present invention is preferably contemplated for operating a push-pull coupling to permit selective tandem operation of two vehicles.