Abstract: A pump includes a cam plate, and an input shaft for rotationally driving the cam plate. A pump housing at least partially surrounds the cam plate and defines a cam plate oil reservoir around at least a portion of the cam plate. A bearing support is at least partially disposed within the cam plate oil reservoir. The bearing support defines a bearing oil reservoir at least partially surrounding a portion of the input shaft. At least one passage extends between the bearing oil reservoir and the cam plate oil reservoir. Dynamic motion imparted on oil within the cam plate oil reservoir facilitates migration of oil from the cam plate oil reservoir through a bearing at least partially supported by the bearing support into the bearing oil reservoir and through the at least one passage into the cam plate oil reservoir.

Abstract: The present invention relates to a suction device, including a body. A cavity is disposed in the body. The cavity has a closed end face and an open end face. The open end face forms an end face to suck a workpiece. A tangential nozzle is disposed on a sidewall surface of the cavity. An external fluid enters the cavity through the tangential nozzle along a tangential direction of the cavity. A suction hole is disposed on the closed end face. The suction hole is connected to a suction unit. The suction unit sucks the fluid in the cavity through the suction hole. The suction device can suck a workpiece by using both a rotational flow negative pressure and a negative suction pressure of a fluid in the cavity, and therefore can suppress impact of a workpiece surface on a suction force and generate a larger suction force.

Abstract: A holding device for an aircraft actuator, comprising a body that extends between a lug configured to hingedly connect the holding device to a actuator support body and an attachment flange configured to fixedly attach the holding device to a landing provided by a main body of an actuator. The holding device is configured to prevent movement of the actuator from a normal working position relative to the actuator support body in the event of structural failure of a connection body of the actuator.

Abstract: Roller pairs and draw apparatus for processing glass ribbons are disclosed. The roller pairs applying force to a glass ribbon moving through the draw apparatus. The roller pairs include a first roller assembly and a second roller assembly positioned along opposite sides of the glass ribbon. A shaft of the second roller assembly is coupled to an actuation system that includes a repositionable support member allowing translation of the shaft of the second roller assembly in a direction transverse to the draw direction of the glass ribbon, a pneumatic actuator controlling a position of the contact wheel of the second roller assembly in the direction transverse to the draw direction of the glass ribbon, and a pneumatic reservoir in fluid communication with the pneumatic actuator delivering fluid at an elevated pressure to the pneumatic actuator.

Abstract: A hydraulic motor is provided having radial pistons, with a cylinder block, two main ducts, a fluid distributor, one distribution valve per cylinder, and a control system for controlling the distribution valves. The motor includes at least two elementary motors, and can operate in various different states in which, in each elementary motor, each of the cylinders is connected on the rising ramps to a second main duct and on the falling ramps to a second main duct; a first elementary motor being driving in a first state, and inactive or opposing in a second state, the control system operating the remainder of the hydraulic motor in the same way in these two states. A hydraulic circuit including said motor and a method of controlling such a motor are also provided.

Abstract: A hydraulic system for a mobile machine having an implement is disclosed. The hydraulic system may have a hydraulic actuator configured to move the implement, a storage device configured to store pressurized fluid, and a valve operable to fluidly communicate the storage device with the hydraulic actuator. The hydraulic system may also have a sensor associated with the mobile machine to generate a signal indicative of a speed of the mobile machine, and a controller in communication with the valve and the sensor. The controller may be configured to compare the speed of the mobile machine to a setpoint and to determine an amount of time elapsed while the speed of the mobile machine exceeds the setpoint. The controller may further be configured to selectively operate the valve to fluidly communicate the storage device with the actuator based on the elapsed amount of time and the speed to cushion movement of the implement.

Abstract: The invention relates to a hydraulic drive, especially for two-cylinder thick matter pumps. Said hydraulic drive comprises at least one main pump (10) embodied as a hydraulic variable displacement pump, and two hydraulically actuatable drive cylinders (20, 22) that are each connected to a connection line (16, 18) of the main pump (10) by means of pump connections mounted on one end thereof, forming a closed hydraulic circuit, and communicate with each other at the ends thereof opposing the pump connections (24, 26) by means of a swinging oil line (28). The hydraulic drive also comprises a feed pump (42), by which means pressurized oil is fed from an oil tank to the current low-pressure side into the hydraulic circuit, and a flushing branch (52), by which means a flushing oil flow is branched off from the current low-pressure side under a limited pressure into the oil tank (44).

Abstract: In a boiling water reactor controlling each control rod hydraulically by driving a solenoid valve, the control system comprises an operation control means 41 having a duplicated data processing unit for generating sequence patterns based on the timing of the driving sequence based on the control information provided manually, a transmission control means 42 for creating a command word corresponding to each control rod being controlled based on said sequence pattern, and mutually communicating each command word between duplicated data processing units and computing the AND logic of said data within a predetermined time difference, and when the computed result coincide, transmitting the selected command word serially; a transmission unit 32 for receiving said command word and performing protocol conversion thereto, and transmitting the same to a plurality of transmission branch units positioned downstream as the control command; and a solenoid valve drive circuit 31 for driving the control rod drive unit corres

Abstract: The object of the invention is to provide a device for digital hydraulic pressure transformation with low loss, intended for flow—and power control for hydraulic machines, particularly hydraulic cylinders, which via a switching device are connected to a pressure reservoir with constant high pressure. According to the invention an intermediate mass is present between the switching device and the hydraulic machine which mass is activated by the flowing medium, the intermediate mass being of such size that the average velocity of the flow in the pipe during the open period of the switching device is sufficiently low to bring the hydraulic medium into the hydraulic machine so slowly, that the pressure change at the location of the hydraulic machine is smaller than the pressure difference between the reservoir and the momentary pressure at the location of the hydraulic machine, as result of which a gradual stepwise rising or lowering of said pressure level is made possible.

Abstract: In a device for controlling a hydraulic actuator having an electrically actuated valve which controls the flow of pressure medium to and from the actuator, a controller for the position of the valve piston is integrated in the housing of the valve or arranged on the latter in a housing of its own. In order additionally to integrate axial functionality into a device of this type, a second controller, provided for controlling the pressure or the quantity of the pressure medium fed to the actuator, is arranged in the same housing as the controller for the position of the valve piston. Devices of this type are used for example in machine tools.

Abstract: A control system for a heavy duty hydraulic hammer reduces blank firing of the hammer. The control system provides a reduced flow of hydraulic fluid to the hammer for a selected period of time upon actuation of the hammer and then provides full hydraulic flow increasing the frequency of impacts to full rated values.

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: A hydraulic pump assembly (10) for powering a hydraulic torque wrench (24) is air-powered and has hydro-pneumatic control circuitry (39) which continues operation of an air motor (18) which drives the hydraulic pump (16) for a post-advance period after an advance actuator (55) is deactuated. Operation of the pump (16) is continued for a period sufficient to retract a double-acting torque wrench (24), to permit subsequent advances of the wrench (24) within the post-advance period without restarting the pump (16) or to permit a single acting wrench to be moved from one fastener to the next within the post-advance period without restarting the pump (16). Operation of the pump (16) is terminated when the post-advance period expires if the advance actuator (55) is not reactuated, so as to conserve energy and avoid unnecessary heating of the hydraulic fluid.

Abstract: The invention relates to a pneumatic booster operated by a plunger (9) housed in a bore (61) and carrying a moving seat (102) intended to interact selectively with a shut-off member (111), this member being itself capable of interacting selectively with a fixed seat (101).According to the invention, the plunger (9) comprises a cylindrical body (91) and a collar (92) sliding between a front stop (911) and a rear stop (912) of the body, an anterior section (921) of the collar (92) being engaged between the cylindrical body (91) and the bore (61), a posterior section (922) of the collar (92) carrying the moving seat (102), and it being possible furthermore for the collar (92) to be held temporarily stationary in the bore independently of the movement of the body (91), by means of a channel (14) and of a snap ring (13), in order to allow extended operation of the booster after a sharp braking action.

Abstract: A flow control valve is disposed in a bleed-off line which is for returning to a tank a portion of an oil flow advancing toward a hydraulic motor from a hydraulic pump. Upon operation of a control valve in an accelerating direction, the flow control valve is operated in a closing direction with a certain time lag, while upon operation of the control valve in a decelerating direction, the flow control valve is operated in an opening direction without a time lag. By so doing, an accelerating operation can be done smoothly while maintaining a required torque.

Abstract: In a hydraulic winch having a clutch assembly for freeing a drum of the winch for free falling rotation, a control system is provided for controlling operation of the clutch assembly. The supply system includes a directional control valve shiftable between a first position in which fluid is supplied to the clutch assembly at a first pressure which maintains the clutch in the disengaged position to allow free fall of the drum, and a second position in which fluid is supplied to the clutch assembly at a second pressure which allows the clutch to return to the engaged position, braking free fall of the drum. A timing element shifts the directional control valve to the second position after fluid has been supplied to the clutch assembly at the first pressure for a predetermined length of time.

Abstract: A control system and method for operating the solenoid valves for controlling the supply of hydraulic fluid to a hydraulic actuator is described. The system and the method involves initially applying a first, increasing linear pressure up to a predetermined magnitude and then holding the pressure at that level for a period of time. This predetermined magnitude is equal to the amount of pressure required to cause initial movement of the piston. By holding the pressure level at a plateau for a period of time, the initial movement of the piston is accomplished in a smooth manner. This period of time is relatively short, typically less than one second. Thereafter, the system and the method involve operating the solenoid valves so as to apply a second, increasing linear pressure up to a predetermined final magnitude.

Abstract: To influence the periodic stroke movement of the closing element of a valve, a control cylinder working on the closing element in the stroke direction is provided, which can be acted upon or released by a control element periodically with pressure medium. The control element is connected in the supply or discharge conduit of the pressure medium and can variably accelerate or slow its pressure formation or release and with it also the stroke movement of the closing element, at last gradually. Thus a partially or completely automatic control of compressor valves, for example, can be made possible in a simple manner.

Abstract: A hydraulic pump assembly for powering a hydraulic torque wrench is air-powered and has hydro-pneumatic control circuitry which continues operation of an air motor which drives the hydraulic pump for a post-advance period after an advance actuator is deactuated. Operation of the pump is continued for a period sufficient to retract a double-acting torque wrench, to permit subsequent advances of the wrench within the post-advance period without restarting the pump or to permit a single acting wrench to be moved from one fastener to the next within the post-advance period without restarting the pump. Operation of the pump is terminated when the post-advance period expires if the advance actuator is not reactuated, so as to conserve energy and avoid unnecessary heating of the hydraulic fluid.

Abstract: An electrical connection system is implemented while storage units are being loaded onto a transportation bed 2 or while they are being unloaded therefrom. The system includes an electrical connection constituted by at least one male-type connector 4, 5 and by at least one female-type connector 5, 4, one of the connectors being fixed to the transportation bed 2 or to the storage unit 1, the other connector being driven by a positioning element 6 fixed to the storage unit 1 or to the transportation bed 2, respectively. A control system fixed to the storage unit 1 or to the transportation bed 2 includes a time-delay piston 8 or equivalent time-delay element enabling the positioning element to be controlled.

Abstract: A servo control apparatus comprising: a unit for generating a required position value; an actuator adapted to drive a load and having its maximum displacement in one direction and its minimum displacement in the other direction; a drive unit for driving the actuator; a position detecting unit for detecting a displacement of the actuator; and a control unit for correcting the required position value on basis of the maximum and minimum displacements of the actuator and for computing a deviation between an output of the position detecting unit and the corrected required position value; the load being controlled by the deviation.

Abstract: Equipment for handling containers such as refuse bins for garbage, comprising lifting and tipping structures which are power actuated, and comprising automatic control systems employing micro-processors, sensing and read-out devices by which there is effected automated handling of the bins, determination of the contents and other data relating to garbage collection.

Abstract: A hydraulic driving device includes a working cylinder for moving a machine component, and an electro-hydraulic servo system. The servo system includes a servo-valve, a position-error control, a circuit for emulating speed and acceleration of the working cylinder, and a regulator for weighting the ascertained position error according to the emulated speed and acceleration, and generating a setting signal for the servo valve.

Abstract: An electronic pneumatic limb control system for a pneumatically actuated flexible limb is disclosed. The system includes a computer for providing signal data corresponding to a plurality of successive events of air introduction and non-air introduction, respectively, into the flexible limb during a predetermined limb movement. The computer signal data provides for time-varying the air introduction to the non-air introduction for the successive events thereof during the limb movement so as to minimize oscillation and overshoot. The system also provides for successive events of air exhaustion and non-air exhaustion to return the limb to a position of rest after the predetermined limb movement.

Abstract: A gas valve for providing a short duration, high volume gas pulse includes an outer chamber having an exhaust gas outlet at its front and an inner chamber which extends along the outer chamber, and terminates, at its forward end, in an opening aligned with the gas outlet of the outer chamber and spaced rearwardly therefrom. Within the inner chamber, a piston is mounted for front-to-rear reciprocal movement, and the length of the piston is selected to be greater than the distance between the valve outlet and inner chamber opening. The piston is provided with an intermediate forwardly-directed, peripheral seat, and the piston's front is dimensioned to close the exhaust gas outlet when the inner chamber is filled with gas at a moderate pressure, which forces the piston forward. The outer chamber can then be filled with a charge of gas at a high pressure.

Abstract: The combination of an index table journaled upon a support upon a vertical axis and a computer controlled hydraulic drive including a hydraulic motor connected to the index table. A manifold is mounted upon the support and has a pressurized hydraulic chamber with a hydraulic accumulator mounted upon the manifold in communication with its chamber. A hydraulic power supply is connected to the manifold for pressurizing the accumulator at a pre-set level. An electro-hydraulic proportional valve having a power connector and a hydraulic directional control valve has an intake connected to the accumulator and a pair of outlet feed conduits connected to the hydraulic motor for selectively receiving pressurized hydraulic fluid from the proportional valve for feeding the motor at a predetermined flow, rate and duration for controlled rotational speed, acceleration and duration of incremental rotation of the motor and index table.

Abstract: An actuation installation for use under extreme environmental conditions, such as freezing, uses a two-fluid system in which one fluid is impervious to the extreme environment, and the other fluid, such as water, is not. A two-chamber accumulator-separator has a water chamber connected to a water source via control valves and a working fluid chamber connected to a hydraulic actuator port. The other actuator port is connected to a working fluid chamber of a two-chamber accumulator having a sealed air-pressure chamber. When water is admitted to the water chamber, the actuator will move in a first direction further compressing the air in the air pressure chamber. When the water is drained from the water chamber, the accumulator air-pressure moves the actuator in the opposite direction. The actuator is positioned in the extreme environment, with the remainder of the system installed in a protected environment such as underground.

Abstract: A device for emptying refuse bins, having a tipping frame to engage the bin, a fluid-actuated motor connected to the tipping frame for moving it between a first position wherein it is capable of initial engagement with and holding of the bin, and a second, tilted position, wherein the bin is partially inverted, so as to empty the contents thereof into a larger, collecting container. A switch is provided, responsive to placement of the bin in position on the frame. The device further includes a control circuit having a timing device operated by the switch. The switch initiates operation of the timing device to direct the functioning of the fluid-actuated motor. In a preferred embodiment, the switch is mechanical and is adapted to be engaged by the walls of the refuse bin. Upon the expiration of a predetermined interval established by the timing device, power to the fluid-actuated motor is removed, and the tipping frame carrying the emptied bin is returned to its initial position.

Abstract: The surface of a first fixed member (2) having at least one hydraulic-fluid passage (12, 18) is in contact with the surface of a second movable member (4) controlled by an actuating system (28, 30) and having at least one shut-off zone (6) and at least one recess (20) forming a zone exposing the said passage; at least one of the passages consists of a plurality of nozzles (12) which are pierced in the first member and are at a distance from one another and which are arranged on at least one track (14) directed parallel to the relative movement of the two members; the said actuating system is a step-by-step system driving the movable member in increments of a value d; the recesses (20) and the shut-off zones (6) on the second member are such that the said nozzles are exposed or shut off in turn at each advance of the movable member (4) by an increment d.

Abstract: A control system for operating positive displacement hydraulic motors to minimize pressure peaks and stresses associated therewith upon starting the motor at full fluid flow includes a self-closing pilot operated valve which, upon initiation of fluid flow to the motor bypasses a majority of the flow to a return line circuit and progressively closes to force pressure fluid to accelerate the motor to a preselected operating speed. The self-closing valve includes a spool type closure member which is pilot actuated through a timing orifice to commence closing upon initiation of fluid flow therethrough from the pump discharge or supply line. The closure member is spring biased in the open position and automatically resets itself to the open position upon shutdown of the motor operating valve.

Abstract: The present invention provides a circuit for obtaining higher accuracy and total system response for complex mechanical impedance loads, such as earthquake simulators, and in particular to compensate for limitations in controlling the actual valve spool displacement and adequately stabilizing and controlling it at high frequencies. The improvement circuit includes a state variable filter to extend the band width of servovalve actuation frequencies by adding a lead compensation signal compensating for servovalve hydraulic responses. The output of the first filter circuit then in turn feeds a summing junction where the spool displacement feedback is provided, and the output of the summing junction or circuit is provided with the output from an additional filter which cleans up the signal by filtering out noise and insures that the phase of stabilizing signals is proper.

Abstract: A hydraulic fluid powered actuation system preferably for controlling the position of a control surface of an aircraft in response to a plurality of redundant control signals is disclosed. The system comprises an actuator adapted to be mounted in the aircraft, comprising a housing having first and second cylinders with a piston moveably mounted within each of the cylinders. A piston rod connects the pistons and is adapted to engage the control surface. Two rotary torque motors having a common drive shaft are provided which are adapted to receive the plurality of redundant controls signals. First and second rotary control valves, coupled to the drive shaft, and thus, adapted to be driven by the rotary torque motors, are used to control the emission and exhaust of hydraulic fluid from the first and second cylinders, respectively. Preferably, there are four control signals and the torque motors are DC, multiple-poled torque motors with each coil on each torque motor coupled to a different control signal.

Abstract: A digital proportional valve with valve spool driven in discrete steps by a digital spool actuator in response to a remote manual control signal, while the proportional valve may be provided with positive and negative load compensation.

Abstract: A load dynamic compensation circuit for a servohydraulic control system for fixtures and specimens being tested operating in various degrees of freedom, for example in an environment to simulate earthquakes to test building specimens, or to provide road profile simulation for rail and automobile vehicles, or wind buffet loads for aircraft. A compensation circuitry compensates for specimen displacement disturbances in the control loop that are a function of the force exerted from the specimen and the acceleration of the test mass.

Abstract: An active pneumatic mechanism and a passive hydraulic mechanism of the apparatus are so connected with each other and with a driven member that movement imparted by the pneumatic mechanism to the driven member produces, and is controllable by restriction of, hydraulic fluid flow within the hydraulic mechanism. Restriction of the fluid flow to any desired extent is accomplished by command signals directed by a control computer to a valve that preferably is of the type actuable by a torque motor. The command signals produced by the computer are based upon a correlation of data supplied by a computer program with data supplied by a monitor of the positions of the driven member along its path of travel. Precise control of the speeds, accelerations and positions of the driven member are realized.

Abstract: Grinder-mixers include a material infeed device such as a feed table for feeding bales of hay to be ground up and incorporated into livestock feed rations. Due to varying bale density, the bale grinder sometimes lugs down when encountering a dense bale. However, if the feed table continues to feed bales during such a lug down, the grinder may clog and stall. A bypass apparatus solves the feed table problem by providing a bypass valve automatically operable to stop motion of the feed table when a lug down occurs.

Abstract: A hydraulic rotary actuator which comprises a harmonic drive and a hydraulic motor completely enclosed in the casing of the harmonic drive so that the rotation of the motor is taken out through an output shaft fixed to the drive at a reduced speed. In the casing of the harmonic drive there are provided an electromagnetic brake which acts on the motor, means for increasing the performance of the magnetic brake, means for magnetically shielding the supporting shaft of the hydraulic motor, and means for detecting the angular position of the motor and that of the output shaft relative to the supporting shaft of the motor.

Abstract: An electro-hydraulic proportional actuator in which the actuator piston position is hydraulically controlled by fluid flow through solenoid valves operable by an electronic control system. An operator control provides an input voltage representing a desired piston position and a transducer generates a voltage representing the actual piston position. The difference between the input and output voltages generates a difference or error signal that is fed into a feedback system including a sample-and-hold circuit. A clock logic system is provided for transmitting the signal from the feedback system to the solenoid valves at predetermined intervals to activate either valve to move the actuator piston in either direction or to activate both valves to hold the piston at a desired position.

Abstract: A programmable manipulator is provided in which the manipulator arm is counter-balanced in all of its major axes and these axes are provided with low friction joints so that a relatively small force is needed to move the arm in each of its principal axes. A separate low power driving source is then used to move the arm during the teaching operation, this low power driving source being capable of developing the relatively small force needed to move the arm at low speed during the teaching operation, but being incapable of moving the arm at high speed or exerting a torque on said arm which will be potentially harmful to programming personnel. After the desired path has been taught, the manipulator apparatus is switched over to a playback mode wherein a second relatively high power source is employed to move the arm at relatively high speed during successive playback cycles.

Abstract: An electric stepping motor, operated by command pulses from a computer or microprocessor, rotates a rotary control member of a distributor valve, for sequencing hydraulic pressure and flow to the cylinders of one or more axial piston hydraulic motors. A group of the cylinders are subjected to pressure and flow and the remaining cylinders are vented to a return line. Rotation of the rotary control member sequences pressurization by progressively adding a cylinder to the forward edge to the pressurized group and removing a cylinder from the trailing edge of the pressurized group. The pistons of each new pressurized group function to rotate a wobble plate into a new position of equilibrium and the hold it in such position until another change in the makeup of the pressurized group. An increment of displacement of the rotary pressurized group. An increment of displacement of the rotary hydraulic motor occurs in direct response to each command pulse that is received by the stepping motor.

Abstract: Grinder-mixers include a material infeed device such as a feed table for feeding bales of hay to be ground up and incorporated into livestock feed rations. Due to varying bale density, the bale grinder sometimes lugs down when encountering a dense bale. However, if the feed table continues to feed bales during such a lug down, the grinder may clog and stall. A bypass apparatus solves the feed table problem by providing a bypass valve automatically operable to stop motion of the feed table when a lug down occurs.

Abstract: A servomechanism in which the mutual angular position of a threaded spindle relative to a tap is adjustable by a stepper motor wherein the unit of the threaded spindle and tap is connected directly or indirectly with a hydraulic working unit, the servomechanism includes a ball bearing arranged between the spindle and the tap. Consequently, by actuating the stepper motor to which the tap is connected via a coupling, the tap being rotated and moved in axial direction relative to the spindle, thereby actuating a switching mechanism connected to the working unit by which the spindle is caused to rotate. Accordingly, the relative axial movement between the spindle and the tap is compensated and the working unit is in a different position.

Abstract: A linearization circuit for use with servovalves for controlling reciprocating actuators. The circuit will maintain a substantially linear flow as a function of spool position from the servovalve regardless of the differential pressure across the servovalve orifices, for example the differential pressures which result from changing direction of movement of the controlled actuator under a high load. A differential pressure signal from the actuator, which correlates to differential pressure on the servovalve orifices is processed to provide a compensation signal combined with the normal control signal to achieve the desired output.

Abstract: A pulsed-flow apparatus for spectrometers and the like has a mixing chamber and two syringes each adapted to contain a different liquid and both connected to the mixing chamber. The plunger of each syringe has an outwardly extending rod provided with a toothed rack. A pair of electric armatures are provided, each reciprocable lengthwise of one of the rods and carrying a pressure spring which moves with the armature and, during each move of the armature towards the syringe, advances the plunger deeper into the syringe by the length of one tooth of the rack, but does not extract it when the armature subsequently moves in the opposite direction.

Abstract: This invention relates to a pneumatic cylinder and valve control system in which a block and two plates bolted to the block form one end of the cylinder. This block and plate combination, moreover, provides the housing for the valves and conduits that comprise the pneumatic control system for the operation of the cylinder. To produce greater force, moreover, two pistons mounted within the cylinder on the same line of action both are in fluid communication with the pneumatic control system.

Abstract: An electrohydraulic follow-up amplifier comprises a hydraulically operated prime mover constituted by a cylinder and a piston axially movable therein and fixedly connected to a connecting member. The arrangement includes further an electronically controlled motor, for instance a direct current servomotor driving for instance a nut meshing with the threaded spindle carrying a control member cooperating with valves for control flow of pressure fluid into and out from cylinder chambers to opposite sides of said piston of said prime mover. The spindle is connected to the connecting member over a coupling comprising a cylinder fixed to the connecting member and a piston fixed to the spindle.

Abstract: A control circuit for an air-spring shock absorber controls pressurization or depressurization of the air chamber of the shock absorber in response to the output signal condition of a level sensor. The control circuit includes a first signal path that conditions the operation of an air pump for pressurizing the air chamber, and a second signal path that conditions the operation of an exhaust valve for depressurizing the air chamber. A timing circuit delays the enablement of the air pump and exhaust valve until the level sensor output signal condition associated with the actuation of the pump or valve has existed for a minimum predetermined time period. The timing circuit includes an R-C time delay circuit with an instant reset to avoid cumulative signal build-up. The control circuit is comprised of a set of digital logic gates which are preferably implemented by standard integrated circuit chips.

Abstract: The invention relates to impact wrenches for tightening threaded joints comprising an impact clutch accommodated in a housing and having a hammer which is axially movable for imparting each blow, and a device for automatically limiting the number of blows to a pre-set number of blows. The device for automatically limiting the number of blows comprises a blow number setter, a movable member directly co-operating with the hammer and axially movable upon each axial displacement of the hammer so as to enable the axial displacement of the hammer until a pre-set number of blows are delivered, and a locking device for locking the movable member against displacement in the position preventing further axial movement of the hammer after the ultimate blow of the pre-set number of blows is delivered. Thus the possibility of imparting blows in excess is eliminated without deenergization of the impact wrench drive, and the construction of the impact wrench is simplified.

Abstract: Automated control apparatus for an intermittently extended hydraulic cylinder is disclosed which governs cylinder elongation such that the rate of elongation is essentially constant with respect to time. The control apparatus includes a preset continuously variable timer that regulates the timer interval between sequential length increments of the cylinder. The control apparatus also includes a second timer which is responsive to the timer interval interposed by the first timer and which operates a valve controlling communication of hydraulic fluid between a hydraulic cylinder and a pump. The second timer may be discretely variable so that one of a plurality of predetermined length increments can be selected. Alternatively, the second timer may adjust the time period during which the valve is opened such that successive stages of a telescopic hydraulic cylinder have equal length increments.

Abstract: An hydraulic power system comprising a dual acting work piston adapted to be operatively connected to an external mass to be moved, the piston being instantly directionally responsive to a pair of control valves adapted to be sequentially opened and closed to actuate the work piston for movement in opposite directions, the control valves each having a series of sequentially acting valve elements which control fluid flow to and from the work piston, the system forming an hydraulic closed loop which is completely filled with fluid during both charging and discharging, the work piston and control valves working at all times against solid columns of fluid under controlled positive pressures, the system being capable of developing accelerating forces having a magnitude up to 500 G's and of being operated both directly or remotely utilizing electronic, mechanical or hydraulic actuating means with no appreciable phase lag between initial actuation and the completion of the work stroke.