Abstract: A method is provided for controlling the bounce of a work implement attached to a machine having an electro-hydraulic system. The method comprises the steps of sensing the operating pressure in an actuator arrangement connected between the frame of the machine and the work implement, monitoring an upper and a lower operating pressure level in the actuator arrangement to establish a threshold pressure level and altering the pressure level in the actuator arrangement in the event the threshold level is exceeded to re-establish the threshold pressure level. Once the original threshold level is attained, the system is reset. This effectively eliminates the bounce of the work implement at the initial onset of the bounce and resets the system to react to future bounces.

Abstract: In one aspect of the present invention, an apparatus for detecting particles within a fluid is disclosed. A bobbin defines a debris collection chamber. Spaced apart first and second coils are wound about the bobbin in the proximity of the debris collection chamber, wherein the inductance of the coils are responsive to the particle accumulation within the collection chamber. An electromagnet is wound about the second coil to attract ferrous particles into the proximity of the second coil. A reference coil is wound about the bobbin to compensate for the changing temperature of the fluid. An oscillator is coupled to the first, second and reference coils for selectively producing an oscillating waveform at a frequency that induces eddy currents in the particles. The frequency of the oscillating waveform is indicative of the amount of accumulation of both the ferrous and non-ferrous particles.

Abstract: In one aspect of the present invention, an apparatus for detecting particles within a fluid is disclosed. A bobbin defines a debris collection chamber. A first coil is wound in a helix about the bobbin in the proximity of the debris collection chamber, wherein the induction of the first coil is responsive to the particle accumulation within the collection chamber. A reference coil is wound in a helix about the bobbin to compensate for changing fluid temperature. An oscillator is coupled to the first and reference coils for selectively energizing the coils with an oscillating waveform at a frequency that induces eddy currents in the particles. The frequency of the oscillating waveform is indicative of the amount of accumulation of both the ferrous and nonferrous particles.

Abstract: The subject arrangement provides a compact leak free mechanism to interconnect an electrical signal between the interior and exterior of a pressure vessel. The electrode sealing arrangement of the subject invention includes a housing, an insulating sealant material member having an enlarged portion with an electrical conducting electrode disposed through the insulating sealant material member, a collar mechanism, and a force transferring mechanism operative to apply a force through the collar mechanism to compress the insulating sealant material member against the housing and the electrical conducting electrode. The force being applied to the enlarged portion compresses it and seals the components from leakage and exerts a holding force on the electrical conducting electrode thus holding it in its assembled position.

Abstract: A control system is provided for a hydraulic circuit having first and second hydraulic valves, a valve spool position sensor, and first and second input devices for producing first and second operation signals. A controller receives a signal from the valve spool position sensor and the second operation signal and responsively modifies the value of the second operation signal in response to the valve spool position signal.

Abstract: Fluid regeneration circuits are useful for filling expanding sides of a hydraulic cylinder with fluid being exhausted from the other side. The currently available circuits pass the excess fluid not needed for filling the expanded side of the cylinder through the directional control valve to the tank such that the directional control valve must be actuated for the regeneration valve assembly to function. A combined meter-out and regeneration valve assembly of the present invention is used in a hydraulic system having a directional control valve for metering in pump to cylinder fluid flow and includes a meter-out valve to meter-out cylinder to tank fluid flow from a head end actuating chamber. The fluid passing through the meter-out valve passes through an exhaust conduit to a tank bypassing the directional control valve. This permits the meter-out valve to be used independently of the directional control valve to retract a hydraulic cylinder.

Abstract: A displacement controlled hydraulic proportional valve has a spring retainer and a force feedback spring serially disposed between a pilot valve spool and a main valve spool in a control chamber. An arcuate convex end portion on the pilot valve spool extends into a cylindrical pocket in the spring retainer essentially defining a contact point through which force is transferred between the pilot valve spool and the retainer. The point contact minimizes side loading on the pilot valve spool due to buckling of the feedback spring to minimize tendency of the pilot valve spool to stick during operation.

Abstract: An apparatus is provided for use in a vehicle having a source of pressurized fluid and a pair of hydraulic drive motors connected to the pressurized fluid source and powered thereby. First and second ground engaging devices are connected to and driven by the first and second motors, respectively. The apparatus includes first and second control members, each being positionable at a plurality of locations for indicating a desired speed and direction for a respective drive motor. First and second actuators are adapted to sense the position of the first and second control members, respectively, and responsively control the direction and rate of fluid flow to the first and second drive motors. A set switch is movable between first and second positions and is adapted to produce a set speed signal in the second position.

Abstract: An apparatus for controllably actuating a hydraulic actuator is provided. The apparatus is connected between a source of pressurized hydraulic fluid and the hydraulic actuator. The apparatus controllably provides pressurized hydraulic fluid to the hydraulic actuator. The apparatus includes a controller for receiving an operating signal and a load pressure signal and responsively actuating the hydraulic actuator.

Abstract: A control system is provided for use with a hydraulic system which includes a source of pressurized fluid, a plurality of flow regulator means, and a plurality of fluidly powered components. Each flow regulator means is adapted to receive the pressurized fluid and is responsive to a respective control signal for regulating the flow of pressurized fluid to respective fluidly powered components. The control system includes a plurality of control members, each being movable to a plurality of locations for indicating a desired fluid output for a respective flow regulator means. A plurality of sensors are provided for sensing the position of respective control members and responsively producing respective position signals. A primary controller is adapted to receive the position signals, process the received signals to responsively produce the control signals, and deliver the control signals to the flow regulator means.

Abstract: An apparatus for limiting the power output of a hydraulic system is disclosed. The hydraulic system has a variable displacement pump. The variable displacement pump has a movable swashplate and is driven by a source of motive power. The apparatus includes a memory device for storing a set of power modes. Each power mode has a predetermined power level associated with the hydraulic system and is defined by a plurality of set points. Each set point corresponds to a predetermined flow rate and discharge pressure of the pump. A device senses the speed of the source of motive power and producing a signal representative of the actual speed in response to the sensed speed. A device senses the pressure of the variable displacement pump and produces a signal representative of the actual pressure in response to the sensed pressure. A device senses the swashplate angle of the variable displacement pump and delivers a signal representative of the actual swashplate angle in response to the sensed swashplate angle.

Abstract: A steering control system is provided in which one pair of wheels of an articulated steer vehicle are steered in synchronization with the articulation steering. This is accomplished by providing a first two-position valve for directing the fluid exhausted from the rod end of one articulation steer jack to the head end chamber of one of the rear wheel steering jacks and to the rod end chamber of the other rear wheel steering jack for steering the rear wheels in a first direction and another two-position valve for directing the fluid exhausted from the rod end chamber of the other articulation steering jack to the rod end chamber of the one rear wheel steering jack and the head end chamber of the other rear wheel steering jack for steering the rear wheels in the opposite direction.

Abstract: High pressure cutoff controls are useful for variable displacement hydraulic pumps for reducing power losses at high pressure levels. Some operators, however, believe that they get more work from pumps not having the high pressure cutoff control. The subject on-off high pressure cutoff control includes an on-off valve disposed in a pilot passage connected to an output port of a pump and to an end of a high pressure cutoff valve. The on-off valve is selectively movable between a first position at which pressurized fluid passes through the pilot passage to the end of the high pressure cutoff valve to prevent it from functioning as a high pressure cutoff valve. Thus, an operator has the option of operating the hydraulic pump with or without the high pressure cutoff control.

Abstract: An apparatus controls a fluid system of a work vehicle. The work vehicle has an engine and at least one fluid circuit which has a pump driven by the engine. A plurality of control valves controllably pass fluid from the pump to a plurality of respective work elements. The control valves have movable valve stems. A work attachment which has a respective control valve is added to the fluid system. A plurality of operator control elements provide demand signals in response to selected settings. Each demand signal is indicative of a requested fluid flow to a respective work element or work attachment. A memory device stores select parameters of the fluid system. One of the select parameters is a predetermined priority value representing the precedence in which fluid is delivered from the pump to the control valve of the work attachment. A controller receives the predetermined priority value of the work attachment and the demand signals.

Abstract: Hydraulic hammers are normally controlled by an actuating valve which controls the flow of fluid from a source of pressurized fluid to the hydraulic hammer. During certain periods of operation, the actuating valve totally blocks communication of fluid to the hydraulic hammer, thereby causing the fluid from the source of pressurized fluid to be expelled through a relief valve. The subject hydraulic hammer and control arrangement therefor includes an accumulator for storing the pressurized fluid from the source of pressurized fluid during periods of fluid blockage by the actuating valve and for supplementing the flow of fluid from the source of pressurized fluid when the actuating valve is communicating pressurized fluid to the hydraulic hammer. This increases the overall efficiency thereof.

Abstract: Impact rippers are useful in fracturing rocks, concrete, etc. which cannot be fractured by ripping alone. Operating the impactor of the impact ripper without sufficient loading applied to the ripper tip is detrimental to the life of the impact ripper. The subject control system includes a pilot operated selector valve which blocks pressurized fluid from the impactor in the absence of pilot fluid thereto and is shifted by pressurized pilot fluid to a position to direct pressurized fluid to the impactor. A pressure switch is rendered conductive when the fluid pressure generated in a hydraulic cylinder exceeds a predetermined value due to loading on the ripper tip. This actuates a solenoid valve to direct pressurized pilot fluid to the selector valve. Thus the impactor is activated only when the loading on the ripper tip is above a preselected threshold and is automatically deactivated when the loading on the ripper tip drops below the preselected threshold.

Abstract: Impact rippers are useful for ripping solid rock. The service life of the impactor can be extended if the impactor is operated only when the ripper shank is loaded sufficient to transmit the impact energy into the material being ripped. The subject control system uses control signals generated by a plurality of signal generating means when the ripper shanks are loaded above a predetermined level to control the operation of the hydraulically actuated impactors associated with such ripper shanks. The number of control signals being generated is also used to control the volume of fluid made available for use by the impactors being operated at an given time to control the operating speed thereof. Thus, only the impactor(s) associated with a ripper shank(s) loaded above the predetermined level is operated thereby avoiding non-productive and harmful impactor operation if the ripper shank(s) is not sufficiently loaded.

Abstract: Hydraulic hammers are useful for transmitting high impact blows to a tool for fracturing hard material. When two hammers are used in combination the impact blows delivered to a common tool by the hammers should be synchronized for maximum effectiveness. The subject synchronized hydraulic hammer arrangement includes a valve arrangement for alternately directing pressurized fluid to a variable volume chamber in each of a pair of hydraulic hammers to simultaneously retract a piston of each hydraulic hammer against the bias of pressurized gas in a gas chamber of each hydraulic hammer and exhausting the variable volume hydraulic chambers in response to at least one of the pistons reaching a predetermined position. The gas chambers are interconnected for equalizing the gas pressure therein. This arrangement of components provides synchronized movement of the pistons in an outward direction so that they simultaneously impact against the common tool.