Abstract: A hydraulic system for a motor grader is disclosed. The hydraulic system may include a first hydraulic subsystem and a second hydraulic subsystem. A pump may be configured to provide pressurized fluid to the first and second hydraulic subsystems. The hydraulic system may further include a control valve located upstream of the first and second hydraulic subsystems. The control valve may be configured to vary a standby pressure of pressurized fluid for use by the first and second hydraulic subsystems.

Abstract: A flow control valve for a construction machine is provided, which can constantly control a flow rate of hydraulic fluid supplied to a hydraulic actuator through a flow control spool in a spool. The flow control valve for a construction machine, having a valve body in which a supply passage communicating with a pump passage and actuator ports connected to a hydraulic actuator are formed, and a spool installed in the valve body to be shifted, includes a flow control spool shifted in the spool to variably control a cross-sectional area of a passage connected to the one actuator port if a flow rate of the hydraulic fluid that flows through the supply passage is higher than a set flow rate, a first passage formed on the spool to communicate with the supply passage and a second passage formed on the spool to communication with the one actuator port and having a cross-sectional area that is varied depending on the shifting of the flow control spool.

Abstract: A hydraulic system is disclosed that utilizes a switching block to selectively allow pressurized fluid to be stolen from a master or lift cylinder and directed to a single acting cylinder to perform a function, such as securing an implement to a vehicle. The system utilizes the highly pressurized hydraulic fluid from an extended lift cylinder to maintain a secondary cylinder in an extended position. To withdraw the secondary cylinder, a one-way valve directs fluid to the opposite chamber of the secondary cylinder. The secondary cylinder, however will only retract if the master cylinder is retracted and not under pressure, thus providing a significant safety benefit in certain applications. This system provides many cost efficiencies and may be utilized by work vehicles to perform secondary functions such as attaching and removing an implement from a vehicle such as, for example, a loader from a tractor.

Abstract: A hydraulic system that allows pressurized fluid to be stolen from a master or lift cylinder and directed to a single acting cylinder to perform a function. The system utilizes a spring in the single acting cylinder to force the fluid to retract through the same single line that powered the single acting cylinder. The fluid is then routed to the unloaded side of the master cylinder. This system provides many cost efficiencies and may be utilized by work vehicles to perform secondary functions such as attaching and removing an implement and locking and unlocking a loader.

Abstract: The invention relates to a hydraulic control apparatus (1) for a shifting fork (7) for engaging/releasing at least one gear (G) in a manual transmission, comprising at least one shifting cylinder (2, 3) and a piston unit (6) which can move within the shifting cylinder and is connected to the shifting fork (7), and at least one control valve (8) for generating a modeled pressure which can be applied to the piston unit (6) in order to actuate the shifting fork (7). To prevent jolting when the piston unit is started up, the invention proposes a valve apparatus which provides a counter-pressure which counteracts the movement of the piston unit (6). In a preferred exemplary embodiment, a diaphragm ensures that the counter-pressure drops below the value preset by the valve apparatus at low speeds on the part of the piston unit.

Abstract: In the construction machinery equipped with an engine, a hydraulic control unit and a machine controller, there is provided an antitheft device for the construction machinery, which can prevent the engine from starting and the hydraulic control unit from working with reliability no matter how the starter circuit of the engine is modified. The initial state of the machine controller is so set that the fuel injection by a fuel injection unit of the engine is halted and that the operations of control units in the hydraulic control unit are halted, and an antitheft control unit is provided to release the initial state of the machine controller upon receiving a release signal from the antitheft control unit.

Abstract: A control system controls actuation of a hydraulic cylinder on a skid steer loader. The control system includes a movable element, movable by an operator. A position sensor is coupled to the movable element and provides a position signal indicative of a position of the movable element. A controller is coupled to the position sensor to receive the position signal and provide a control signal based on the position signal. A valve spool controls flow of hydraulic fluid to the hydraulic cylinder. An actuator is coupled to the controller and the valve spool and moves the valve spool in response to the control signal from the controller.

Abstract: A lifting device for lower steering arms of a tractor has a position recording device (25). The position recording device (25) generates a position signal representing the pivot position of the lower steering arms (2, 3). A piston-cylinder unit (11, 12) acts on the tractor and on the lower steering arm (2, 3). A switching circuit is provided per piston-cylinder unit (11, 12). The switching circuit includes a directional valve (33, 33′) with four ports and four switching positions. In a first position of the directional valve (33, 33′) all ports are blocked. In a second position, the cylinder chamber at the piston end is connected to the pressure agent supply source and the cylinder chamber at the piston rod end is connected to the return line. In a third position, the cylinder chamber at the piston rod end is connected to the pressure agent supply source and the cylinder chamber at the piston end is connected to the return line.

Abstract: An hydraulic valve has two outlets and is switchable so that fluid can only be supplied to one outlet at a time. A spool with two seals is slidable in a housing under the action of two proportional solenoids and is urged to a central position by two springs where the seals block passage to both outlets. When the spool is moved in one direction it allows flow to one outlet and also allows flow via a bypass channel to an opposite side of the spool counteracting the force applied by the solenoid so that the force applied to an outlet can be controlled gradually.

Abstract: A device and method for selecting a control mode in a power construction vehicle is disclosed. The device has a control mode select switch which selects a function for setting new matching relations between the control levers and the proportional control valves. A controller sets the new matching relations and stores the new matching relations, and controls the actuators in accordance with the new matching relations. In the control mode selection method, one operational motion of an actuator is primarily selected and displayed on a display means. Thereafter, a voltage signal indicative of a levering angle of a control lever associated with the selected actuator is output, thus setting a new matching relation between the control lever and an associated proportional control valve. The above process is repeated in order to continuously set and store new matching relations between the control levers and proportional control valves associated with the other actuators.

Abstract: A steering control system for an autonomous machine has a manual steering control valve for directing fluid from a pump to either a head end chamber or a rod end chamber of a hydraulic steering actuator. In one embodiment, an electrically actuated steering valve device is disposed in series flow relationship between the pump and the manual steering control valve and is operative to direct fluid from the pump to the head end and rod end chambers. In another embodiment, a electrically actuated device mechanically actuates the manual steering control valve for steering the machine.

Abstract: When an operator makes the reversing-lever operation by operating a control lever 4A in a direction x.sub.2 in the event a solenoid proportional valve 91A of a directional control valve 8A is failed to be left open, an operation position sensor 30A.sub.2 outputs a low-level signal and operation position sensors 30A.sub.1, 30B.sub.1, 30B.sub.2 output high-level signals. Therefore, an AND circuit 6b.sub.2 outputs a low-level signal and an AND circuit 6b.sub.1 outputs a high-level signal, whereupon a switch signal is output from an amplifier 6h to a solenoid switching valve 121 for shifting it to a right-hand position shown in FIG. 1 so that a pilot line 51 is kept communicated with a reservoir 97. No switch signal is output from the amplifier 6h to a solenoid switching valve 122 for holding it in a left-hand position shown in FIG. 1 so that the pilot line 52 is kept communicated with a pilot pump 96.

Abstract: An interlocking change-over valve system for use in a hydraulically controlled mechanism includes a plurality of hydraulic actuators and at least one valve corresponding to each actuator for controlling the hydraulic pressure supplied to each actuator. A hydraulic cylinder communicates with each valve for opening and closing the valve. A control device remotely activates the hydraulic cylinder to selectively supply hydraulic pressure to some of the hydraulic actuators.

Abstract: A partial width seeding attachment includes electronically controlled solenoids which activate hydraulic flow control valves connected to the hydraulic cylinders on respective implement sections. Switches in the tractor cab control the rockshaft of one or more selected sections independently of the other sections to raise the openers on the selected section or sections from contact with the soil. An electronically activated flow reversing valve is connected between the source of hydraulic fluid under pressure and the lift cylinder for each of the sections. Activation of a selected valve after the selective control valve on the tractor is moved to the normal field working position pressurizes the side of the cylinder that raises the openers on the section. The remaining cylinders operate normally to maintain preselected down pressure on the other openers. A master raise switch provides implement lift independent of the position of the individual rockshaft control switches.

Abstract: An electro-hydraulic control system for a mineral mining installation has a series of valve blocks, each contain a number of valves which are operated in dependence on electrical signals to cause hydraulic appliances of roof supports to operate. To allow emergency operation, when there is a power failure or when the control system fails or is otherwise inoperative, further manually operable valves are connected by a flexible, multi-core connecting cable to the valve block of the associated support. The emergency control valves can operate hydraulically controllable direction control valves of the control system and by-pass the electrical controls. The support can then be controlled purely hydraulically, at least in its main functions, using the emergency device.

Abstract: A remote control modification (11) for a hydraulic steering system (13) of the type used to steer underground loaders and the like is disclosed. The remote control modification comprises a bidirectional, spring-loaded remote control valve (51) connected in parallel with the bidirectional, spring-loaded control valve (19) that normally responds to steering inputs created by the manual movement of a steering arm (25). The remote control valve (51) has outlet ports (75 and 77) that are smaller than the outlet ports (39 and 41) of the manual control valve (19). Movement of the piston of the remote control valve (51) is controlled by a slave hydraulic actuator (53). The flow of hydraulic fluid to the slave hydraulic actuator (53) is controlled by a solenoid-actuated valve (59). The solenoid (61) of the solenoid-operated valve (59), in turn, is controlled by a receiver (63) that responds to radio frequency control signals (105) generated by a remotely located transmitter (65).

Abstract: A time division multiplexed (TDM) hydraulic control system having a plurality of channels, each channel having a servo actuator. Electrical demand signals are arranged in TDM sequence and applied to a single multiplexed pilot valve so that the pilot valve produces a plurality of hydraulic signals. Commutator means are associated with the pilot valve for distributing the hydraulic signals to the associated channels. In order to achieve useful output flow rates in the channels, each channel includes a second stage valve which integrates the hydraulic signals for its channel to produce an output flow rate which is a function of the integrated signal. The flow rates are continuously produced (as compared to the multiplexed output signals) and are coupled to actuators in the channels for controllably adjusting the position thereof. Feedback means associated with the actuators includes rate feedback for stabilizing the multiplexed control loops.

Abstract: This system is a multiple hydraulic control unit to be quick coupled to any existing hydraulic system on a machine or tractor that has male or female breakaway couplers, and a flow control valve. This multiple hydraulic control arrangement can be easily transported from one hydraulic power unit to another, such as a farm or garden tractor, simply by uncoupling the hose connections and wiring harness, then connecting them into another power source. The electric components of this system consist of; 12, 24, or 120 volt solinoids, a control handle, or control box, which are placed within easy reach of the operator. Then the operator selects which selector valve is to be used by depressing one of the momentary switches installed into the handle or control box. When the selector valve is selected, the operator controls the oil flow with the existing permanently installed control valve.

Abstract: A time division multiplexed (TDM) hydraulic control system having a plurality of channels, each channel having a servo actuator. Electrical demand signals are arranged in TDM sequence and applied to a pilot valve so that the pilot valve produces a plurality of hydraulic signals. The hydraulic signals in turn are coupled to a separate commutator which distributes the hydraulic signals to the associated channels. The pilot valve is arranged with a full annular output port to maximize the port area and thereby the flow rate to the channels. The commutator size and port area is coordinated to that of the pilot valve to minimize pressure drop across the commutator and to maximize flow rate to the channels.

Abstract: A data transmission/reception system usable for bi-directional data transmission in electro-hydraulic control systems between two adjacent supports of a mine installation which each have their own transmitting and receiving stations in a control unit. Bi-directional data exchange takes place via a single wire data bus which is used for simultaneous transmission and reception and forms the summation point for adding the transmitted signals from two transmitters. Each transmitting and receiving station is provided with a subtraction circuit connected to a receiver of the respective transmitting and receiving stations and to which the transmitted signals from its own transmitter are supplied in each case at the subtraction circuit input. The other input of the subtraction circuit is connected to the bi-directional data bus.

Abstract: A hydraulic operated control system for remotely operating a walk-behind soil compactor. A remotely operated three-position valve is connected to the pressure line of the hydraulic system of the soil compactor and serves to control the flow of hydraulic fluid to opposite ends of a hydraulic cylinder unit that is operably connected to a hydraulic pump which operates the speed and direction control for the compactor. The cylinder unit includes a piston that is slidable within the cylinder and the piston is biased to a neutral position by springs. Through remote operation of the valve, hydraulic fluid will be directed to either end of the cylinder to provide direction and speed control for the compactor. A deadman switch is located on the remote control panel and manual release of the deadman switch will open the hydraulic circuit between the opposite ends of the cylinder to prevent fluid from being directed to the cylinder and will enable the springs to return the cylinder to a neutral no speed position.

Abstract: Apparatus for confirming the clamping conditions of a clamping device which is used to clamp workpieces of different sizes. Signals corresponding to the kind of workpiece being clamped are derived from the flow rate of pressurized fluid used to drive the actuator of the clamping device. These signals are used to confirm the clamping conditions and also the kind, and the presence or absence, of the workpiece.

Abstract: In a selective control device for plural kinds of oil-hydraulic actuators comprising an actuator selective valve for selecting an operative oil-hydraulic actuator from among plural kinds of oil-hydraulic actuators and a directional control valve for operating the selected actuator extendedly and retractedly, the actuator selective valve is provided with a quick extensional position which functions to connect an extensional pressure port thereof to a bottom side oil chamber of the selected actuator and also to connect a head side oil chamber to the bottom side oil chamber in order to extend the selected actuator quickly. The construction of the actuator selective valve eliminates a quick extensional valve adopted in a prior oil-hydraulic control device.

Abstract: A hydraulic adjustment apparatus for use in adjusting and positioning microwave radiating antenna or any other treatment monitoring device is disclosed. The hydraulic adjustment apparatus, generally comprises an upper portion having a box-like member suitable for accommodating therein a mounting member; a plurality of upper adjustable leg member means; a plurality of upper switch valve means with associated plurality of upper tubular means attached thereto; as well as a plate member for joining said upper portion to a lower portion of said hydraulic adjustment apparatus. Said lower portion, generally comprises a plurality of lower tubular members; and lower adjustable leg member means operably coupled to a base member having a preferable microwave radiating antenna or any other treatment monitoring device integrally coupled thereto.

Abstract: The invention relates to a method for the simultaneous actuation of a plurality of hydraulic consumers by means of intrinsically-safe electro-hydraulic valves. The consumers are connected by hydraulic directional control valves to a pressure line and/or a return line. These hydraulic directional control valves can be connected in a predetermined manner, via pre-control valves to a control line. The pre-control valves are pressureless, and possess electro-magnets with a current consumption of less than 50 milliamps. By connection of a series-connected electro-hydraulic directional control valve means, the pre-control valves are connected to the control line, and at the same time are hydraulically locked.

Abstract: Valves regulating the supply of hydraulic fluid to hydraulic cylinders of an hydraulic walking mine-roof support are controlled by apparatus comprising an axially-movable switching shaft provided with cams which is rotatable into successive switching stations where it is immobilized by spring-loaded stop pins to that the cams bear on tappets to actuate the respective valves, there being a switching spring acting on the shaft to return the shaft to its initial position of rest after it has been axially displaced and rotated out of that position of rest.

Abstract: An electro-hydraulic control system includes a plurality of two-position control valves, each controlling fluid flow into and out of a corresponding one of a plurality of hydraulic functions. First and second pressure responsive servo actuators associated with each control valve operate to move each control valve to first and second positions, respectively. A two-position, solenoid-operated, pilot valve controls fluid flow into and out of a pilot circuit. The pilot circuit communicates fluid to and from the second servo actuator of each control valve and to and from a plurality of two-position, soleniod-operated, pilot valves. Each pilot valve controls fluid flow into and out of the first servo actuator of a corresponding one of the control valves. A detent mechanism holds each control valve in either its first or its second position in the absence of fluid pressure in the servo actuators.

Abstract: An arrangement for supplying pilot oil to a servo-valve arranged to activate a main valve of a hydraulic system. The hydraulic system also includes a hydraulic oil pump, a valve located between the pump and the main valve, a pressure reducing valve located between the pump and the servo-valve, and at least one auxiliary assembly is arranged to deliver an electric signal to electromagnetic means arranged to activate the servo-valve. In accordance with the invention, the valve located between the pump and the main valve is arranged to be substantially or fully closed when standing at a given, pre-determined pressure corresponding to the servo pressure required by the servo-valve in order to carry out its intended function, and is arranged to be open when the pressure slightly exceeds the aforementioned pre-determined pressure. An electromagnetically operable shunt valve is located between the pump and pressure reducing valve and, when open, to pass oil direct from the pump to a tank.

Abstract: A hydraulic vehicular transmission has a plurality of drive speed establishing devices (e.g. clutches) to be actuated for selecting a drive speed, and a pair of similar drive direction establishing devices to be actuated for selecting a drive direction. The drive establishing devices are all actuated and deactuated hydraulically by respective solenoid operated control valves via respective pilot operated valves. Since the solenoid valves are susceptible to malfunctioning, as in the event of trouble in the associated electrical circuitry, emergency control valves are interposed respectively between the solenoid valves and the pilot operated valves. Each emergency control valve is to be hand operated in the event of the malfunctioning of the associated solenoid valve for actuating or deactuating the associated speed or direction establishing device via the associated pilot operated valve. Additional features are incorporated for the greater utility of the transmission control system.

Abstract: A hydraulic circuit system of a construction machine having first and second hydraulic circuit, and a bypass circuit for connecting the first and second circuits together. The first circuit includes a first hydraulic pump and a first valve group having a plurality of directional control valves for controlling a flow of hydraulic fluid from the first pump, and the second circuit includes a second hydraulic pump and a second valve group having a plurality of directional control valves for controlling a flow of hydraulic fluid from the second pump. A plurality of actuators are driven by the hydraulic fluid supplied from the first and second pumps through the valves. The bypass circuit includes a bypass line for connecting the first travel valve in series with the second travel valve in a position downstream thereof through the selecting valve.

Abstract: Container handlers comprise a plurality of double-acting hydraulic cylinders to effect the various side shift, twist lock, tilt, height adjustment, and spread modes of operation. Separate control valves and hoses, entrained over the mast assembly having the attachment thereon, are required to effect such functions selectively. This invention is directed to a programmed electro-hydraulic control circuit when reduces the required number of hoses to two and provides a non-complex system which can be operated expeditiously.

Abstract: A control system for longwall mining roof supports which are controlled in dependence on the position of the mining machine at any time. All of the roof supports are connected to a central computer via common conductors. Each of the roof supports includes a control unit having a code corresponding to the number of that support. This code serves as an address and enables the central computer to transmit its control command signals positively, in response to the mining machine position signals, through an appropriate address control unit for a particular roof support. In order to enable roof supports to be actuated manually also, the control units of all of the roof supports are connected to the central computer by two common conductors, one of which carries an automatic enable signal and the other of which carries a manual enable signal.

Abstract: Disclosed is control apparatus for a machine such as crane which includes a remote control assembly fluid-coupled to the machine by a substantially electrically non-conducting tube assembly. The machine can be operated remotely from the remote control assembly or from an electrical control assembly disposed at the machine. Apparatus is provided for automatically shutting down all or selected machine functions in response to a blockage in one or more of the fluid lines extending between the remote control apparatus and the machine. In a preferred embodiment, the remote control assembly includes pneumatic switches coupled by the fluid lines to electric pressure switches disposed at the machine. The pressure switches are in turn coupled to electro-mechanical devices for controlling the machine functions.

Abstract: A control system for a plurality of hydraulic actuators which requires smaller number of control valves than that of actuators. In one embodiment, three control valves are arranged in parallel for controlling four hydraulic cylinders. The control valves are preferably solenoid-operated and one of control valves are used for supplying a pilot fluid pressure into a plurality of pilot-operated check valves disposed between the control valves and the hydraulic cylinders.

Abstract: Fluid control systems frequently eliminate use of fluid operated jack protecting relief valves because additional visibility blocking and damage prone conduits are required to connect the relief valves to the reservoir. A fluid operated system having a controlling valve, a selecting valve, a fluid operated jack, a relief valve, a reservoir and a bypass valve is provided to controllably connect the relief valve to other portions of the system in response to the position of controlling valve and selecting valve. Therefore, no additional conduits are required to connect the relief valve to the reservoir and thus the problems of reduced visibility, premature conduit leakage and conduit damage are eliminated. The fluid control system is particularly suited for use in a work vehicle such as a lift truck having a lift mast.

Abstract: An electro-hydraulic control system for an underground mineral mining installation employs individual control assemblies and devices on a series of support units which are interconnected to one another and to a central control station via lines conveying electrical control signals. Manually-operable selector switches on the units enable groups of the support units to be operated in sequence at will by operating the switches of adjacent units outside the group.

Abstract: A locomotion unit is remotely controlled to advance stepwise through a passageway by frictional engagement with the surfaces of the passageway walls. A support section is mounted on the locomotion device to bring special tools to bear at predetermined positions within the passageway to which the support is brought by the locomotion unit.

Abstract: Method and apparatus for hydraulically controlling subsea well equipment, such as valve operators, connectors, and other hydraulically actuated devices, with a significantly smaller number of hydraulic pressure source lines from the surface to the subsea location of said well equipment and for providing return signals to indicate the state of operation of said well equipment using the same hydraulic lines. The apparatus includes a plurality of hydraulic AND-gate logic elements and a plurality of hydraulic valves mounted near the well equipment. A pair of hydraulic lines between the hydraulic valves and a surface vessel or other surface facility provides control for the various valve operators, connectors and other hydraulically actuated devices, while a third hydraulic line provides power to operate the various devices. The same pair of control lines can be used to transmit signal information from the various devices on the sea floor to the surface vessel to indicate the operating status of these devices.

Abstract: Control valves govern the operation of a plurality of hydraulically-activated devices movable between extended and retracted positions. The control valves are interconnected to a plurality of control lines which carry hydraulic fluid and activation of a particular control valve will establish a certain hydraulic signal pressure pattern within the control lines indicative of a certain commanded position of one of the devices. A decoding section responsive to the signal pressure pattern allows for high pressure hydraulic flow to the selected device and in addition sets up a low pressure return path therefor. A significantly greater number of devices can be controlled with a relatively few control lines thereby reducing construction, maintenance and material costs.

Abstract: Apparatus primarily for use in extracting and re-inserting heat exchanger tube bundles in chemical processing plants. An elongated frame structure having first and second pairs of spaced parallel beams is provided, with a carriage attachable to the tube bundle and moveable along the frame structure first beams in response to actuation of extraction cylinders. No portion of the frame structure extends above the first parallel beams, and an arm is mounted on each corner of the structure, pivotal about an axis perpendicular to the direction of tube withdrawal, and a cable extending from a central crane is mounted on each arm. A cylinder pivots each arm about its axis to change the position of the supporting crane back relative to the center of gravity of the structure. A pair of moveable side arms with clamps are provided for engaging a flange on the heat exchanger shell, and attitude control slings are also provided.

Abstract: A hydraulic control system is provided for a mine roof support assembly constituted by a plurality of roof support units positioned side-by-side. The control system comprises a respective control valve assembly having a plurality of similar control valves each of which controls a respective hydraulic appliance associated with the corresponding roof support unit. Each control valve can be actuated optionally by an actuator mounted on either one of the two adjacent roof support units, or by either one of two actuating devices mounted one on each of said two adjacent roof support units. Each control valve includes two servo valves having a pair of first and second axially aligned servo-pistons which are separate and independently operable with respect to each other.

Abstract: A hydraulic control arrangement for hydraulic consumer includes a multiple position valve having a control slide movable by proportional magnets between a neutral position and a plurality of working positions, in which the magnets may be remote controlled from an analog desired value signal and in which a stop valve is provided in a control circuit leading from the consumer to an over-pressure valve, which in turn is connected, upstream of the multiple position valve, parallel to the consumer between a pressure conduit connected to a source of pressure and a return conduit connected to a tank.

Abstract: An apparatus for controlling the hydraulic system of hydraulic actuators, such as hydraulic cylinders. The apparatus is constituted only by a combination of two kinds of control valves in that normally opened and normally closed, solenoid-operated, spring-returned type control valves are serially connected together through a common port formed in each control valve.

Abstract: A self-advancing mine roof support is provided, in addition to the normal manually operable control valve means for controlling raising and lowering of the roof-engaging structure of the support and operation of the advancing means, with an automatic sequence control valve means operable in response to a control signal from a position removed from the support, for example from an adjacent support, and an isolating valve means arranged so that control of the various operations can be effected either by means of the manually operable means or from the safety of a location spaced away from the support being controlled by means of the automatic valve means each independently of the other.