Abstract: A suspension for the boom of a loading vehicle includes a hydraulic cylinder for raising and lowering, or for extending and retracting (in the case of a telescopic cylinder), a boom. A direction control valve is provided for selectively routing hydraulic oil to and from at least a head-end chamber of the cylinder. A position sensor senses the position of the hydraulic piston rod, at the start of operation, and sends a sends a target signal representing this beginning position to a control unit which determines the difference between the target signal and a signal representing a current position of the piston rod. When this difference equals a preset difference threshold, a pressure-limiting unit, in the form of a valve or choke, is activated so as to control fluid flow to and from the head-end chamber so as to return the piston rod to its initial position which generated the target signal.

Abstract: An operation mechanism for a variable displacement hydraulic pump. The hydraulic pump is disposed in a housing filled with fluid. A capacity regulating member is provided on the hydraulic pump in the housing for changing the discharge amount of the hydraulic pump. An operation member is operationally connected to the capacity regulating member. The operation member is to be manipulated outside the housing. A resistive device is interposed between the operation member and the capacity regulating member for making the motion of the capacity regulating member slow. The resistive device is an assembly unit comprising a casing, a piston slidably disposed in the casing, and fluid filled in the casing. The casing is fitted into the hole provided in the housing.

Abstract: A tractor-mounted front end loader includes lift boom having a tool, disclosed as a bucket, pivotally mounted to one end of the boom for selected movement by one or more hydraulic adjustment cylinders. A safety valve is associated with one of the pressure chambers of each adjustment cylinder to prevent unintended lowering of the tool in the event a supply-return hose extending between a direction control valve and the adjustment cylinder should rupture. Also connected to this pressure chamber of each adjustment cylinder is an accumulator for providing a damping action. The connection between the pressure chamber and the accumulator is made by rigid tubing, and in one disclosed embodiment, includes a remotely operable on/off valve for selectively coupling the accumulator to the pressure chamber.

Abstract: An electronic control for damping oscillation of a swinging backhoe assembly includes a crossover valve that connects the hydraulic lines that supply hydraulic fluid to the boom swing cylinders to each other whenever an electronic controller senses incipient oscillation or swinging of the backhoe assembly. The electronic controller senses such parameters as pressure in the conduits and the position of the operator controls or the position of the boom swing control valve that the operator controls to determine incipient oscillation when the backhoe assembly is stopped. The crossover valve may remain open for a predetermined period of time.

Abstract: There is disclosed a hydraulic control arrangement for damping driving vibrations of a mobile machine, comprising a lifting cylinder supporting a working tool whose cylinder chambers can be connected to a fluid source or a tank via a control valve arrangement. The hydraulic control arrangement has a damping valve arrangement including a control valve in which a check valve is integrated through which a bottom-side chamber of the lifting cylinder is connectable to a hydraulic accumulator. In the pressure control function the accumulator can be connected to a tank so that the accumulator pressure is restricted to a maximum value.

Abstract: A muffler is received in a passage of an end member connected to a handle of the staple gun and a fitting extends from the end member so as to be connected to a hose. The muffler includes a tubular body and a plurality of plates extend from an end of the tubular body. The plats extend toward an interior of the handle and form a bullet-head-shaped arrangement. Gaps are defined between the plates and become smaller when air goes outward from the handle so as to reduce noise.

Abstract: A method is provided for attenuating noise in a hydraulic circuit having a pump in fluid communication with a hydraulic actuator by a conduit. The method includes supplying a flow restricting device in the conduit and generating a signal representative of a fluid fluctuation in the conduit downstream of the flow restricting device. A bypass loop is provided in parallel with the flow restricting device and the bypass has a valve. The valve is controlled based on the generated signal to generate a corrective fluid flow to attenuate the noise.

Abstract: In order to damp the vibrations in a hydraulic branch of a power distribution transmission, the hydraulic pump (1) and the hydraulic motor (3) which are interconnected are non-rotatably but elastically maintained in the transmission housing in the area of their connecting point by damping elements (5). The input shaft (11) of the hydraulic pump (1) and the output shaft (18) of the hydraulic motor (3) are connected with shafts (12, 17) which on their engagements have crowned teeth or spiral gearings and are floatingly mounted. It is hereby obtained that the hydraulic branch is easy to mount, can freely move and the vibrations it produces are not transmitted to the transmission housing (7) or to the toothed wheels (13, 16) of the mechanical distribution branch.

Abstract: The invention concerns a vibration absorber (7) with a housing (8) wherein is mounted a block of elastic material (22) defining a cavity (9) and sealingly closing it. The invention is applicable to motor vehicles.

Abstract: A two-way orifice check valve device for a hydraulic circuit is disclosed. The hydraulic circuit which controls the engagement and release of a friction element, such as a clutch, is simplified to reduce the manufacturing cost, as well as improve functioning during the engagement and release of the friction element.

Abstract: A control section outputs a reference signal which corresponding to a frequency and an amplitude of signals sent from a vibration generation source. The pulse width modulation section generates a drive control signal to, an electromagnetic valve, connection of an air chamber and is alternately switched between the side of an inlet port and the side of the atmosphere. The drive control signal corresponds to an amplitude of the reference signal and is composed of at least the same number of pulses corresponding to a duty ratio-changed frequency as that of each one period of the standard signal. The drive control signal is synchronized with the standard signal. The number of pulses of the drive control signal for each period of the reference signal is changed corresponding to a control frequency of the standard signal so that the number of pulses and the control frequency is not larger than a responding frequency of the electromagnetic valve.

Abstract: A hydraulic clutch actuator system having a vibration damper in the system including an elastomeric diaphragm and a steel diaphragm. One face of the elastomeric diaphragm is in communication with fluid in the system so that the diaphragm may deflect in response to low frequency system vibrations to effect damping of these vibrations. The steel diaphragm is positioned generally parallel to and proximate the other face of the elastomeric diaphragm so as to form a back-up for the elastomeric diaphragm so that the elastomeric diaphragm may deform against the steel diaphragm in response to high frequency system vibrations to cause deflection of the steel diaphragm to effect damping of the high frequency vibrations. An apertured stop structure above the elastomeric diaphragm functions to limit upward excursions of the elastomeric diaphragm and further functions to maintain communication between the chamber above the elastomeric diaphragm and the damper port to the system.

Abstract: What is disclosed is a hydraulic control arrangement for attenuating travel vibrations of a mobile working tool, comprising a lift cylinder supporting a working tool, the cylinder chambers of which may be connected to a pressure medium source or to a tank via a control valve arrangement. The hydraulic control arrangement moreover includes an attenuation valve arrangement for connection of one cylinder chamber with an hydraulic accumulator and of the other cylinder chambers with a tank. In accordance with the invention, the attenuation valve arrangement includes a valve having a pressure limiting function and arranged between a check valve and the hydraulic accumulator, so that the pressure in the hydraulic accumulator may reliably be limited to a maximum value.

Abstract: A hydraulic motor is rotationally driven as pressure oil from a hydraulic pump is supplied by way of a control valve. A remote control valve is adapted to switch the control valve. A bypath line is connected to both hydraulic lines of the hydraulic motor. A communicating valve has a position for closing the bypath line and a position for opening the bypath line. A throttle valve controls the communicating valve, wherein the throttle valve is adapted to set the communicating valve to a closed position at the time when the remote control valve is operated for rotating, and to set the communicating valve to an open position at the time when the remote control valve is returned to a neutral position, as well as to allow the pressure oil of deceleration side to be released by a predetermined time, whereby the flapping of the machine which may be caused, such as at the time when the rotation is stopped in the hydraulic excavator, can be avoided.

Abstract: When a swinging boom driven by a hydraulic cylinder stops, inertia causes continued motion of the boom which increases pressure in a chamber of the hydraulic cylinder. Eventually that pressure reaches a level which causes the boom to reverse direction. Then pressure in an opposite cylinder chamber increases until reaching a level that causes the boom movement to reverse again. This oscillation continues until the motion is dampened by other forces acting on the boom. As a result, an operator has difficulty in properly positioning the boom. To reduce this oscillating effect, a sensor detects when the cylinder chamber pressure increases above a given magnitude and then a determination is made when the rate of change of that pressure is less than a defined threshold. Upon that occurrence, a control value is opened to relieve the pressure in that cylinder chamber.

Abstract: A swing control apparatus for a swing type hydraulic shovel capable of reducing impact at a stroke end of swing at a low cost. For this purpose, the swing control apparatus includes a swing angle detector for detecting that a swing angle of a working machine, which is swingingly driven by swing drive means, is within a predetermined angle range short of a stroke end, and a controller for outputting a speed reduction command to reduce a swing speed gradually from a position at a predetermined angle short of the stroke end of a swing toward the stroke end, based on a swing angle signal inputted from the swing angle detector.

Abstract: A hydraulic clutch actuator system having a vibration damper provided in the system between a master cylinder and a slave cylinder of the system. The damper includes an elastomeric diaphragm and a spring steel diaphragm. One face of the elastomeric diaphragm is in fluid communication with hydraulic fluid in the system so that the elastomeric diaphragm may deflect in response to low frequency vibrations transmitted through hydraulic fluid in the system to effect damping of the low frequency vibrations. The spring steel diaphragm is positioned in the system generally parallel to and proximate the other face of the elastomeric diaphragm so as to form a back-up for the elastomeric diaphragm so that the elastomeric diaphragm may deform against the spring steel diaphragm in response to high frequency vibrations transmitted through the hydraulic fluid to cause deflection of the spring steel diaphragm to effect damping of the high frequency vibrations.

Abstract: A swing cylinder oscillation control circuit and valve for oscillating booms connects two hydraulic cylinders with a shuttle valve and two check valves to provide the higher cylinder pressure to a fluid inlet and a lower cylinder pressure to a fluid outlet of a fast-opening and a slow-closing check valve. The fast-opening and slow-closing check valve uses a poppet and spring to set a valve opening pressure and uses internal flow connections to a large diameter piston that works with mechanically adjustable piston and poppet strokes to control the time for valve closing.

Abstract: A hydraulic system is provided. The hydraulic system includes a a hydraulic actuator, a source of pressurized fluid, and a directional control valve controlling fluid flow into and out of the hydraulic actuator. An accumulator is disposed between a fluid input line and a fluid output line for the directional control valve. A regeneration control valve is disposed between the accumulator and the output of the source of pressurized fluid. A storage control valve is disposed between the fluid output line and a tank of the hydraulic system.

Abstract: A device is disclosed to reduce vibrations in a hydraulic force transfer system which has a master cylinder and a slave cylinder connected with this via a fluid column. The device has a housing and a membrane attached by its edge to the housing. The housing and the membrane delimit a chamber which can be connected via a connection with the master cylinder and via a further connection with the slave cylinder so that the membrane can be hydraulically pressurized by the fluid column between the master cylinder and slave cylinder. According to the invention the membrane is pressed, at least in the rest state of the hydraulic force transfer system, by means of a spring element against the direction of the hydraulic pressure on the membrane against a chamber-side support surface. The result is a simply constructed device to reduce vibrations in a hydraulic force transfer system.

Abstract: The present invention provides a method and apparatus for identifying and eliminating vibration in a hydraulic clutch actuator. The vibration is identified by using transducers to characterize the vibrational characteristics of a power train of a vehicle. That characterization is used to program a shaker on a test bed to replicate the vibrations on the vehicle in a hydraulic clutch actuator. Different hydraulic dampers may be employed to eliminate the vibration. The preferred apparatus of the present invention includes a two piece hydraulic damper which may be opened as to insert different diaphragms for testing.

Abstract: An oil pressure control apparatus for an internal combustion engine that has a source of hydraulic pressure and a hydraulic actuator which is actuated by hydraulic pressure provided via a fluid passage which is in communication with the source of hydraulic pressure. A control valve is disposed in the fluid passage for controlling the hydraulic pressure introduced to the actuator. A damper, which is disposed in a fluid communication between the hydraulic actuator and the control valve, is operative to attenuate the force of a pulsing stream of a working fluid in the fluid passage.

Abstract: A hydraulic power steering system includes a steering gear having a cylinder, and a piston slidably disposed in the cylinder to divide the cylinder into first and second cavities on opposed sides of the piston. A pair of turn tubes are coupled to the cylinder for connecting the cylinder cavities to a source of hydraulic fluid. An open fluid leakage path extends between the cylinder cavities or between the turn tubes. This open leakage path is sized to damp fluid pressure fluctuations and thereby reduce fluid-induced shudder in the steering system. The open fluid leakage path may comprise a valve or a passage extending between the turn tubes, a passage in the piston or in the seal between the piston and the gear housing cylinder, or a passage in a banjo block connected across the turn tube inputs to the gear housing.

Abstract: A casing accommodates therein a movable valve adapted to be moved away from a valve seat by a hydraulic oil flowing through an oil-hydraulic circuit from a hydraulic cylinder to an oil-hydraulic pump. In an event of oscillatory hydraulic pressures in the hydraulic cylinder, the hydraulic oil is returned through the oil-hydraulic circuit from the hydraulic cylinder to the oil-hydraulic pump via a second port, a communication path, a minor gap between the movable valve and the valve seat, and a first port. In this process, the communication path allows for a smooth flow of the hydraulic oil from the second port into the movable valve.

Abstract: An operation mechanism for a variable displacement hydraulic pump. The hydraulic pump is disposed in a housing filled with first fluid. A capacity regulating member is provided on the hydraulic pump in the housing for changing the discharge amount of the hydraulic pump. An operation member is operationally connected to the capacity regulating member. The operation member is to be manipulated outside the housing. A resistive device is interposed between the operation member and the capacity regulating member for making the motion of the capacity regulating member slow. The resistive device is an assembly unit comprising a casing, a piston slidably disposed in the casing, and second fluid sealed in the casing. The second fluid is different from the first fluid. The casing is fitted into the hole provided in the housing. The retaining member retains the casing in the hole.

Abstract: The invention provides a system for regulating pressure equalization in hydraulic mechanisms to suppress oscillation in heavy equipment. The system includes a first and second hydraulic lines, a crossover valve in communication with each of the first and second hydraulic lines, a timing system in communication with the crossover valve, and a motion detector in communication with a heavy equipment component. The motion detector senses a linkage motion and operatively opens the crossover valve, which remains open as directed by the timing system.

Abstract: The invention concerns a hydraulic power-assisted steering system for motor vehicles, with a valve and two hydraulic lines leading from the valve to cylinders of a servo drive mechanism and with at least one steering damper, the steering damper having a basic body 4 which is arranged movably along a path in a working chamber 3 and delimits with an outer wall 2 of the working chamber 3 a first channel through which hydraulic fluid can flow.

Abstract: A system for damping incipient oscillation in a linkage such as a backhoe assembly includes a crossover valve that connects the two supply lines that provide hydraulic fluid to a linkage actuator such as a boom swing hydraulic cylinder. The crossover valve is configured to open in response to the deceleration of the backhoe assembly.

Abstract: A method for controllably moving a machinery platform 20 of a work machine 10 having an electro-hydraulic system 100 is disclosed. The work machine 10 includes at least one swing motor 120 configured to move the machinery platform 20. The changing speed of the swing motor 120 is determined. A solenoid actuated valve 165 is controlled in response to the determination. The solenoid actuated valve 165 is configured to responsively produce a relief valve pilot signal 170. The two-way relief valve 130 is controllably shifted in response to the inputted relief valve pilot signal 170. At least one of a high pressure by-pass valve 135 and a low pressure by-pass valve 140 is selected in response to the two-way relief valve 130 shifting.

Abstract: A swivel control apparatus according to the present invention , includes: a hydraulic pump; a hydraulic motor for swiveling which is driven by hydraulic oil emitted from the hydraulic pump; a control valve which controls a flow of hydraulic oil which is supplied from the hydraulic pump to the hydraulic motor for swiveling, and at a neutral position of the control valve cuts off from one another a pair of ports which communicate to input and output ports of the hydraulic motor; a valve device which communicates and cuts off from one another a pair of conduits which are respectively connected to the input and output ports of the hydraulic motor for swiveling; a pressure detection device which detects respective pressures in the two conduits and outputs pressure signals; a rotational speed detection device which detects a physical quantity based upon a rotational speed of the hydraulic motor for swiveling and outputs a rotational speed signal; a mode selection device which selects a neutral brake mode and a neut

Abstract: A ride control system adapted for use in a fluid system of a machine to cushion the ride of the machine, the machine having a frame with an actuator arrangement disposed between the frame and a load to raise the load relative to the frame, the actuator arrangement having a raise port and being operative in a raise mode to raise the load to a desired height in response to pressurized fluid being directed to the raise port from a source of the pressurized fluid, the ride control system including an accumulator arrangement and a valve arrangement connected between the accumulator arrangement, the actuator arrangement, and the source of pressurized fluid, and operative to selectively connect the accumulator arrangement to the raise port of the actuator arrangement when in the raise mode while maintaining the load at the desired height.

Abstract: A load arm suspension system for a load arm assembly with at least one hydraulic cylinder, which load arm suspension system comprises an accumulator which is connected to a first cylinder space of at least one cylinder. A tank for hydraulic oil is connected to a second cylinder space of the at least one hydraulic cylinder. A first valve member is arranged between the accumulator and the first cylinder space of the at least one cylinder and a second valve member is arranged between the tank and the second cylinder space of the at least one cylinder.

Abstract: A variable rate ride control is disclosed and adapted to control the ride of a machine having varying load conditions. The variable rate ride control system includes an accumulator arrangement selectively connectable to an actuator arrangement of the machine. The accumulator arrangement has a variable pressure rate so that the accumulator arrangement can adapt to varying load conditions.

Abstract: An energy attenuation apparatus for a system conveying liquid under pressure, and a method for attenuating energy in such a system, are provided. The apparatus includes a hose or tubular casing having an inlet opening for receiving liquid from the system, and an outlet opening for returning the liquid to the system. An inlet conduit extends concentrically into the hose or tubular casing through the inlet opening thereof, with an annular space being formed between the inlet conduit and the tubular casing. At least one aperture for introducing liquid into the annular space from the inlet conduit is provided on a portion thereof that is disposed in the tubular casing.

Abstract: This invention relates to a device to reduce pulsations on a hydrostatic positive displacement unit, such as an axial piston machine or a radial piston machine which can be used both as a pump and as a motor. The direction of rotation of the positive displacement unit is reversible and at least one piston is mounted so that it can move longitudinally in a cylinder bore forming a cylinder chamber. The device has a buffer element which can be brought into communication with the cylinder chamber by a connecting channel.

Abstract: A quick connect coupling for use in a hydraulic clutch control system including a hydraulic master cylinder and a hydraulic slave cylinder. One of the coupler members of the quick connect coupling includes a central axial passage defining an inlet at one end of the passage and including a diaphragm positioned at the other end of the passage at right angles to the passage in fluid communication with fluid flowing through the passage. The passage further includes a radial passage portion communicating with the central passage and extending to a fluid port for the coupler member. Hydraulic fluid flowing through the coupler member communicates with an inboard face of the diaphragm so that the diaphragm functions to attenuate pulsations in the hydraulic fluid and preclude transmission of the pulsations rearwardly in the system to the clutch pedal.

Abstract: This invention relates to a device to reduce pulsations on a hydrostatic positive displacement units, such as an axial or radial piston machine working both as a pump and as a motor with a reversible direction of rotation. In the displacement units, at least one piston is mounted so that it can move longitudinally in a cylinder bore which forms a cylinder chamber. The device has a buffer element which is in communication with the high-pressure side and can be brought into connection with the cylinder chamber. The device reduces pulsations on hydrostatic positive displacement units by which the reversing actions of the cylinder chambers are optimized and the pulsations are effectively minimized in a broad bandwidth of operating conditions. A switchable valve, in particular a non-return valve which opens toward the cylinder chamber is located in a connecting channel between the buffer element and the cylinder chamber.

Abstract: The invention relates to a damper valve arrangement, which can be combined with a servomotor of a hydraulic power steering system to form a steering damper. For calibration purposes, the damper valve arrangement has a bypass duct with a calibratable throttling resistance.

Abstract: In machines having a bucket that is capable of carrying a load of material, it is well known that when the machine encounters a bump or other obstacle that the effects thereof may result in a shock or jolt being subjected to the machine due to the sudden change in forces acting on the actuator of the lift mechanism. In the subject invention, an accumulator arrangement is connected through a first valve mechanism to the loaded end of an actuator to provide a cushion or damping of the sudden changes in the forces. The first valve mechanism controls the magnitude of the damping in response to the rate of flow between the actuator and the accumulator arrangement. This is accomplished by sensing the pressure drop across a flow restriction mechanism located upstream of the first valve mechanism and controlling the degree of fluid communication between the actuator and the accumulator arrangement in response thereto.

Abstract: A hydraulic control system in a construction machine is provided with a hydraulic pump delivering hydraulic oil, a directional control valve controlling flow of the hydraulic oil, an actuator driven by the hydraulic oil outputted from the directional control valve, and a tank into which the hydraulic oil delivered from the hydraulic pump is bleeded. A cut-off valve controlling flow of the bleeded hydraulic oil is arranged between the directional control valve and the tank. Transient characteristics are added to a signal controlling the cut-off valve so that variation of the signal is suppressed to be small. Transient characteristics are added also to a signal controlling the hydraulic pump so that variation of the signal is suppressed to be small. Thereby the construction machine can travel smoothly.

Abstract: In a construction machine of a small rotational inertia such as an intrawidth swing machine or a small-sized excavator, a rotative operability varies depending on the posture of a working attachment, and in a reduced state of reach, a change in rotating force is oversensitive to the operation of a working lever, so operation is difficult. To cope with this point, means for detecting the operation of a rotating direction control valve is provided, and an outlet of a center bypassing oil path in the rotating direction control valve and an oil tank are brought into communication with each other through a cut-off valve used for controlling the bleed-off thereof.

Abstract: A hydraulic power steering apparatus includes a pump for discharging pressurized operation fluid, a power cylinder for generating assisting force, a control valve connected to the pump via a fluid path for receiving the operation fluid from the pump and adapted to supply the operation fluid to the power cylinder in accordance with operation of a steering wheel, a rubber hose disposed in the fluid path. A check valve is disposed between the rubber hose and the control valve. Since reverse flow of the operation fluid due to input of kick-back force is prevented, tires to be steered are prevented from undesirably steered against the driver's intention. Further, a pressure relieving mechanism is provided to relieve part of the operation fluid when the check valve operates. Therefore, the oil pressure within the power cylinder and the control valve is prevented from increasing excessively, so that the oil pressure within the pump does not reach a preset relief pressure.

Abstract: A control system for improving the roadability of a wheeled excavator is disclosed herein. The excavator is the type including an implement such as a bucket or backhoe which is moved relative to the excavator by hydraulic actuators. Hydraulic fluid is applied to the actuators via electronic valves which are controlled by an electronic controller. Based upon acceleration of the vehicle, the electronic controller controls the electronic valve to maintain fluid pressure in the actuator or the acceleration substantially constant. Additionally the controller can be configured to maintain the average position of the implement generally constant. By controlling the pressure in the hydraulic actuator, the undesirable bouncing or pitching of the excavator can be reduced when the vehicle is traveling at road or loading speeds.

Abstract: A control system for improving the roadability of a wheeled excavator is disclosed herein. The excavator is the type including an implement such as a bucket or backhoe which is moved relative to the excavator by hydraulic actuators. Hydraulic fluid is applied to the actuators via electronic valves which are controlled by an electronic controller. Based upon acceleration of the vehicle, the electronic controller controls the electronic valve to maintain fluid pressure in the actuator or the acceleration substantially constant. Additionally, the controller can be configured to maintain the average position of the implement generally constant. By controlling the pressure in the hydraulic actuator, the undesirable bouncing or pitching of the excavator can be reduced when the vehicle is traveling at road or loading speeds.

Abstract: A pneumatic tool of the front exhaust type is composed of a main body, a rotary end member, a connection member, three leakproof rings, a noise reducing plate, and a flow adjusting set. The main body has a tubular extension portion. The rotary end member has a body provided with a first hole and a second hole. The first hole has a hole diameter greater than the outer diameter of the tubular extension portion, and a length equal to the length of the tubular extension portion. The second hole is in communication with the first hole and is greater in hole diameter than the first hole. The connection member is received in the tubular extension portion via the second hole. The connection member has a threaded portion provided with at least one leakproof ring so as to enable the connection member to be fastened pivotally with the rotary end member when the connection member is fastened with the tubular extension portion.

Abstract: The present invention relates to a control system for hydraulic power units, in particular hydraulic cylinder-piston-assemblies comprising a valve to be controlled by an electronic controller, the valve controlling the fluid path between the power unit, a pressure source and a reservoir. A pressure sensor and a circuit for differentiating the sensed pressure quantity in response to time is provided for sensing a respective output variable of the power unit. The pressure variation signal is utilized to assist operating the valve to improve the control operation, i.e. to dampen fluid vibrations or to decrease the hammering noise produced in the operation of stamping, nibbling or shearing machines.

Abstract: A device and method for suppressing vibration of a working machine in which residual vibration produced immediately after an operation is completed can be suppressed well without degrading the response. The device comprises a working machine acceleration detecting means (11H, 11B), a lever turning degree coefficient calculating means (17) for calculating coefficient in accordance with a lever turning degree, an acceleration compensating value operating means (13) for performing an operation from the acting force calculated from the acceleration of the working machine and a lever turning degree coefficient, and a feedback command means (18) for calculating an acceleration feedback command value from an acceleration compensating value and a lever operation command value and for outputting the acceleration feedback command value to electromagnetic proportional pressure control valves (22, 23).

Abstract: A method of suppressing vibrations of an actuation element of a hydraulic force transmission apparatus, especially a hydraulic clutch actuation system in an automobile, and an auxiliary vibrator for carrying out the method, are disclosed. The force transmission apparatus possesses a transmitter cylinder connected to the actuation element, and also a receiver cylinder connected to that cylinder by a liquid column, by which receiver cylinder a low-frequency excitation vibration is transmitted to the liquid column, which propagates in the latter as a low-frequency pressure pulsation.

Abstract: A rest portion is used to support a load at an adjustable height relative to a base which is connected to the rest portion by a pivotal linkage. A hydraulic ram coupled to a gas spring cylinder applies a spring force between the linkage and the base, the geometry of the linkage and ram being such that the upward component of spring force is invariant with respect to height adjustment. A control valve allows the ram to be locked at a selected height and the spring force provided by the gas spring is adjustable by movement of a second piston within the gas spring cylinder to vary the available volume of gas. A hydraulic pump is used to supply hydraulic fluid to the cylinder for adjusting movement of the second cylinder. The apparatus is suited for use in a chair-bed enabling a patient to be supported at an adjustable height during medical treatment.

Abstract: Method and improved apparatus for reduction of fluid borne noise in a hydraulic system are disclosed. A shortened noise suppression assembly comprising first, second and third volumetrically compliant members with first and second inductive flow members providing fluidic coupling therebetween is disclosed. The shortened noise suppression assembly acts similarly to an electronic low pass filter network in deterring fluid borne noise from entering portions of the hydraulic system located therebeyond. At least one of the first and third volumetrically compliant members are comprised within a stub line. The remaining one, or ones, of the first, second and third volumetrically compliant members, and the first and second inductive flow members form conduit members of a passage for connecting a pump to the portions of the hydraulic system located therebeyond.