Abstract: A proportional actuator valve (110) adapted for position control and position adjustment is provided. The proportional actuator valve (110) includes a valve housing (112) having at least two chambers (324, 325). The chambers are separated by one or more sealing members (322). A valve slider (113) is provided that is movable in the valve housing (112). One or more grooves (329) are formed in the valve slider (113). The one or more grooves (329) pneumatically communicate with the two chambers (324, 325) of the valve housing (112). One or more bores (327, 328) are also formed in the valve slider (113). The one or more bores (327, 328) pneumatically communicate with the one or more grooves (329). Movement of the valve slider (113) relative to the valve housing (112) provides a pneumatic valve action.

Abstract: A system is provided for maintaining the position of a valve in a compressor. The valve includes a valve body connected to a piston in a cylinder by a shaft. The valve body is positioned in the discharge outlet of the compressor based on the location of the piston in the cylinder. The system maintains the position of the valve body in response to a movement of the piston by permitting fluid to flow from a fluid source through the piston and into a chamber of the cylinder to urge the piston back to its initial position in the cylinder.

Abstract: A pneumatic actuator is provided for an active bonnet. The pneumatic actuator includes, but is not limited to a cylinder and a piston transferable from a rest position to an extended position and lockable in its rest position. The piston, in its rest position, is held pre-stressed by a spring element in the direction of the extended state.

Abstract: Automatic-locking hydraulic jack of the type that includes a piston (1, 30) that slides into a cylinder (3-2, 32), in which the locking of the piston is achieved by elastic deformation of either the inside wall (2) of the cylinder or of the outside wall of the piston (30) so as to ensure that the one is tightly clamped over the other, characterized by the fact that the locking of the jack is achieved permanently by way of pressure that causes the elastic deformation of the inside wall of the cylinder (3-2) or of the outside wall of the piston (30), whereby the unlocking of the jack is achieved by neutralizing this permanent deformation.

Abstract: A balancing vertical load device for a motor, to be used in conjunction with a vertical driving device with a force- and position-controlled motor, comprising a motor assembly and a sealed air pressure system. The motor assembly has a motor, and a load weight which, driven by the motor, performs a vertical movement. The sealed air pressure system has an air cylinder, a piston, gliding inside the air cylinder with low friction and being connected with the load weight, an air container, storing a relatively large air volume, and an air pressure source. The sealed air pressure system balances a load of the load weight, so that precise control of force and position of a vertically moving object, as if moving horizontally, is achieved.

Abstract: A pressure regulating valve (20) for adjusting a pressure of a supply/discharge passage (10) to a pressure balanced against a weight of a body to be carried (1) is provided. The supply/discharge passage (10) is connected to a working chamber (8) of a cylinder (2) for raising and lowering the body to be carried (1). A control valve (38) for increasing and decreasing a pressure in a control passage (28) in accordance with a balance between the weight of the body to be carried (1) and a working force in a reaction force chamber (42) to which a pilot pressure is introduced from the control passage (28) is also provided.

Abstract: A depth control system particularly useful for single point depth control on an agricultural implement includes a valve and actuator mounted directly to the pivotal connection areas of a hydraulic cylinder that controls height. Cylinder motion directly controls valve actuation independently of complicated linkages to reduce the size and cost of the system and substantially overcome hysteresis problems.

Abstract: A method and device for automatically adjusting the lightening of a working unit (U) of a machine by use of a hydraulic ram (57) associated with a hydropneumatic accumulator (67). Use is made of a second hydraulic ram (58) of which the piston (53), which can move as far as a predetermined position (PP) in the cylinder (C2) and which is detached from the rod (46) of the first hydraulic ram (57), acts directly or indirectly on the latter rod via the oil (O) contained in the first hydraulic ram (57). The working unit (U) is raised and lowered by the second hydraulic ram (58). When raising the working unit (U), the volume of oil in the first hydraulic ram (57) is increased or decreased in such a way that the working unit (U) is always at a predetermined height (HP) at the end of raising travel.

Abstract: The invention discloses a power unit (1) which comprises: an accumulator battery (2); an electric converter (3) supplied by said accumulator battery (2); an electric motor (30) supplied by said converter (3); a hydraulic pump (4) mechanically connected to said electric motor (30), suited to put under pressure a liquid (50) which supplies one or more actuators (9) in order to lift a load (11) connected to them. Said pump (4) is of the reversible type and operates as a hydraulic motor suited to drive into rotation said electric motor (30) which operates as a generator supplying said battery (2) by means of said converter (3) whenever the descent by gravity of the load (11) supported by said one or more actuators (9) puts under pressure the oil held therein which passes through said pump (4) entering from the delivery opening (42) and coming out of the inlet opening (41).

Abstract: An actuator assembly comprises a piston within an actuating cylinder, and a valve for controlling the flow of actuating fluid to the first side of the piston. When the valve is actuated the flow of fluid to the first side of the piston is stopped and the pressure of the actuating fluid on the piston is sufficient to maintain the piston in a predetermined position along the stroke path. Also disclosed is a method of actuating the crust breaker of a smelter pot using the apparatus described. Fluid leakage through the piston rod sealing assembly is reduced; the volume of compressed air used by the smelter is reduced; and the working life of the actuator is improved.

Abstract: A flotation control system for controlling the boom of a tractor or brush cutting machine. Three hydraulic valves operate together and work in conjunction with the existing main valve of the tractor or brush cutting machine to provide flotation control or automatic movement up and down of the boom in response to ground surface variations. The system also allows the amount of weight that the cutter or other attachment exerts against the ground to be increased or decreased. The first valve is a flow control valve or a flow restricting or dividing valve that divides hydraulic flow from the pump of the tractor to the flotation control system. The second valve is a pressure reducing valve that provides the general operation of the flotation control system. The third valve is a directional valve and functions as an on/off for the flotation control system.

Abstract: A control valve is disclosed which is capable of supplying a required control pressure to an actuator such as a brake booster, for example. The control valve includes a valve mechanism within a housing, and the valve mechanism comprises a piston which is associated with a solenoid. When the solenoid is excited, the piston is driven for movement to switch a flow path within the housing. In this manner, the atmosphere, acting as a control pressure, is introduced into a variable pressure chamber defined within the housing. The atmosphere which is introduced into the variable pressure chamber is arranged to push back the piston, so that a control pressure which depends on the magnitude of a current passing through the solenoid can be generated within the variable pressure chamber. As compared with a prior art arrangement, the control valve of the invention reduces the cost of the entire arrangement, and allows a piping arrangement for pressure fluid to be simplified.

Abstract: A pneumatic or hydraulic cylinder assembly (10) includes a cylinder (10), a piston (12) axially slidable within the cylinder (10), and structural elements are disposed within the cylinder (10) to issue a piston (12) position signal in response to the piston reaching a predetermined position.

Abstract: A load balancing arm is shown and described as having improved control including a programmable control element and electronic air regulation to provide precise and controllable lifting force on a load. The disclosed load balancing arm responds to slight operator applied force to aid in movement of the load in overcoming system hysteresis, friction and load inertia without requiring the operator to apply a sufficiently large magnitude force to overcome such counteracting forces in the system. The disclosed load balancing arm further includes automatic load weight detection sensors for accommodating variation in load weights while applying a lifting force to the load which substantially equals the weight of the load. This allows the operator to move the load freely throughout a work space.

Abstract: A height control valve is for controlling the height of an air spring is disclosed, wherein the controlled height of the air spring can be easily adjusted. The height control valve comprises an interior bore in communication with an inlet port, an exhaust port and an air spring port. A hollow piston is movable within the valve bore in response to changes in the height of an air spring. A sealing member is biased onto a valve seat to seal the inlet port, and an open end of the piston abuts the sealing member to seal the exhaust port. Movement of the piston toward the sealing member disengages the sealing member from its valve seat, placing the spring port into communication with the inlet port. Axial movement of the piston away from the disk valve places the spring port into communication with the exhaust port through the interior of the piston. The controlled height of the air spring is adjusted by adjusting the axial position of the seat within the valve bore.

Abstract: A device for limiting a working stroke of a hydraulic cylinder has a working cylinder and a working piston comprising a hollow piston rod connected to its top portion. A pressure reservoir is connected to a first working chamber for constantly supplying a pressure medium thereto, and a pressure source is connected via an inlet line to a second working chamber for supplying a pressure medium thereto. A shut-off valve comprises a push piston and a return spring for holding the push piston in its closed position. A drag link is slidably connected inside the push piston and extends through the working piston into the interior of the hollow piston rod. One end of the drag link has a first abutment that comes into contact with the working piston before the working piston reaches its end position.

Abstract: An improvement of a brake booster is provided which is also provided with the function to serve as an automatic braking unit. A front bead of bellows disposed in a constant pressure chamber is supported by and urged against the wall surface of a front shell by a support of a support member. When the atmosphere is introduced into the internal space within the bellows to cause the brake booster to serve as an automatic braking unit, even though the front bead of the bellows is axially pulled as the bellows expands, a leakage around a seal where the front bead is connected is prevented because the front bead is urged against the wall surface of the front shell by the support member.

Abstract: A method and an arrangement for positioning accurately the piston of a load-carrying pressure-fluid piston-cylinder device, in which the fluid is a compressible gas and the cylinder device is double-acting. A variable operating pressure (P1) acts on one side of the piston, and an applied pressure (P2) of constant value acts on the other side of the piston. The pressures (P1,P2) can be relieved alternately by evacuation, for movement of the piston in the cylinder device. A pressure regulator is provided which functions to detect the load acting on the cylinder device from an external load (F) and which includes a pressure chamber having a movable wall supporting the cylinder device, and in which the operating pressure (Pi) is applied via a valve, the opening and closing movements of which are determined by movements of the movable wall.

Abstract: A hydraulic servo cylinder device for controlling a speed reduction ratio or clutch operation in a continuously variable transmission comprises cylinder and a piston slidably fitted in a cylinder chamber of the cylinder. The cylinder chamber is divided by the piston into a rod-side cylinder chamber and a head-side cylinder chamber, the rod-side cylinder chamber being supplied with a hydraulic line pressure, the head-side cylinder chamber being supplied with a hydraulic control pressure. When the piston is moved to a position near a head-side stroke end, the control pressure in the head-side cylinder chamber is so set that a hydraulic force which the piston receives from said control pressure is in equilibrium with a hydraulic force which the piston receives from the line pressure.

Abstract: A servo system includes a tubular drive shaft journalled in a housing. A screw is engaged threadably with a nut which is fixed in the drive shaft. A driven body is secured to an end of the screw so that the screw can effect a rectilinear movement with the driven body but cannot rotate. A motor can rotate the drive shaft in an infinite angle through a gearing so that the drive shaft can move in a first direction continuously. Then, an end of a fork is rotated by an abuttment element which is sleeved on the drive shaft. At this time, the other end of the fork activates a hydromechanical servo, and hence a hydraulic driving unit, to move the drive body in a second direction which is equal and a opposite the first direction. After which, the drive shaft is moved back to the original position by the driven body. The driven body is therefore moved a predetermined distance.

Abstract: The sealing apparatus is designed to automatically maintain the pressure of a buffer fluid above that of the sealed fluid. The apparatus consists of a cylinder (1) which has a movable piston (4, 5) therein. The piston (4, 5) is coupled to a valve shaft (8) and a first chamber (Z) in communication with sealed fluid is disposed on one side of the piston and a second chamber (Y) is on the other side of the piston for continuous communication with the buffer fluid. Recharging means in the form of a valve (12) and third chamber (X) which contains buffer fluid is a pressure greater than (Y) are associated with the second chamber (Y) so that in response to failure of seals the buffer fluid pressure drops in chamber (Y) and the pistons (4, 5) rise so that shaft mounted valve (12) is disengaged from valve seat (14) allowing high pressure buffer fluid to be transferred from chamber X to chamber Y.

Abstract: A method and device for adjusting pressure fluid cylinders, the fluid being a compressible gas such as air and the cylinder being double-acting and receiving a piston (2). A force transmitting means (12, 20, 24) sensing the load of a cylinder generates a signal corresponding to the size of the load which signal is led to a pressure regulating means (17) adjusting the pressure in the cylinder (1) in dependence of the signal so that this will balance a force acting on the piston rod (3). The load-carrying piston (2) is then positioned in a stationary position relative to the cylinder (1).

Abstract: An input pressure detecting device is arranged in an input side of a pneumatic brake booster, which comprises an elastic member having a given portion which expands when a pressure is applied to the elastic member, a pressure sensor for issuing, upon receiving a pressure, a signal representative of the intensity of the pressure applied thereto, and an axially movable piston intimately disposed between the given portion of the elastic member and the pressure sensor. Upon application of force to the elastic member due to depression of the brake pedal, the elastic member is compressed causing the given portion to expand and thus applying a corresponding but small pressure to the pressure sensor through the piston.

Abstract: A fluid control system of this invention is constituted by a controller and a cylinder (21). The controller comprises: for example, a box (4) having a first chamber (18) having a fixed volume to which a fluid is supplied from a fluid pressure generating source and a second chamber (19) of a variable volume which is connected to a cylinder port (29), such chambers (18) and (19) communicating with each other by a fluid passage (2); a casing (8) engaged with the box (4) for relative movement in the direction of action of a load and having a fluid discharging passage (15) communicating with said second chamber (19) of said box (4); and a valve (5) arranged so that fluid passages (2, 3) respectively between the first chamber (18) and the second chamber (19) and between the second chamber (9) and the fluid discharging passage (15) are closed in the case of no application of a load or an external force while they get into different states in the case of application thereof.

Abstract: A fluid cylinder control method for monitoring the position or controlling the movements of a piston which is slidably guided in a cylinder tube and is acted upon on at least one side by a pressure medium, in particular, maintaining the piston in a predetermined position against the action of eventual disturbance forces. This is attained in that the force which is transmitted between the piston and the cylinder by way of the parts which are slidingly guided on each other, and in particular the friction force acting by way of the seal gaskets of the piston and/or of the rod, is measured and the loading of the piston by a pressure medium is varied in the sense of reducing the measured force.

Abstract: A fault detector for a triplexed mechanical or hydromechanical system which provides for improvement in cost, reliability and weight over previously known balance beam arrangements for achieving redundant two-channel operation to provide a fail-operating first failure mode for operation of aircraft components which require reliable operation for flight safety. The fault detector for a triplexed mechanical or hydromechanical system has a tripodal summing member which receives three mechanical position signals in three different channels with the tripodal summing member retaining a position perpendicular to the force transmitted by the tripodal summing member in response to the position signals and tipping when one of the input signals deviates significantly from the other two.

Abstract: An arrangement for controlling the lifting mechanism of a tractor or a harvester or a harvester combine comprising a hydraulic actuator (17) connected to the lifting mechanism and controlled by a control valve (19) leaving a hydraulically controlled spool arranged in the bridge diagonal (27-19-27') of a hydraulic bridge circuit (23, 24, 25, 26), in the bridge branches of which two actual force value transducers (41, 42) for generating hydraulic signals proportional to the position of the lifting mechanism and desired force value setting means (32, 52) are respectively located for controlling the hydraulically controlled valve (19). An additional control valve (33) or throttle unit (53a) is provided for selecting one or both of the actual force transducers and if desired for controllably mixing the actual force signals.

Abstract: Disclosed is a tilt cab truck in which the weight of the cab is partially supported by the tilting cylinder while the cab is in the over-the-road position. A fluid-by-pass circuit is provided to permit the cab to perform limited up-and-down movement relative to the frame of the truck.

Abstract: A hydraulic positioning system for precisely and rapidly positioning objects of the type likely to impose impact loadings on the system. The system is particularly adaptable for use in sawmill setworks for precisely positioning logs preparatory to sawing thereof. High impact loads are compensated for by special rapid-acting shock-absorbing hydraulic relief circuitry responsive to differences between impact overpressure and system pressure.

Abstract: A process for controlling pneumatic servomotor of the type comprising a control by a motor jack supplied with pressurized fluid by a pressure modulator of said fluid and a first slaving loop causing said jack to slave in a given reference position, wherein each reference position is stored in analogue manner by movable mechanical friction means carrying said modulator and displaced by means of a second disengageable slaving loop which is substituted for the first during reference position changes and which takes its displacement energy for the movable mechanical means directly from the motor jack.

Abstract: A control valve arrangement for a servo-steering mechanism which includes a valve control member responsive to arbitrary steering motions of a steering wheel by executing relative movement with respect to a valve housing. The control member is subdivided into two coupling elements movable relative to each other, which coupling elements are mutually resiliently supported. One of the coupling elements is, in a geared manner, connected to the steering wheel with the other coupling element being provided with four control edges cooperating with corresponding control edges of a valve housing. Two of the control edges control a throttling of two pressure medium connections of one working pressure chamber of the servo-steering mechanism with the other two control edges controlling a throttling of two pressure medium connections of a second working pressure chamber of the servo-steering mechanism.

Abstract: An absolute-control numerical hydraulic actuating device with display of the output position, comprising a hydraulic jack, a distributor formed with orifices and a selector connected to the orifices in order to make the required hydraulic connections for hydraulic locking in the desired output position.According to the invention, the orifices of the distributor can be selectively connected by the selector to the active chamber of the jack in order hydraulically to lock the output positions in accordance with numerical orders supplied to the selector, and additional intermediate locking positions are created by the provision of additional rows of orifices which can be selectively connected to the high-pressure source, to the low-pressure source, or to the active chamber of the jack through a further selector.

Abstract: A height sensor is provided in a vehicle leveling system having an air spring including a pressurized chamber connected between sprung and unsprung vehicle masses. In one embodiment magnets located on a pair of followers within the chamber and attached for movement with the unsprung mass produce magnetic fields which pass through the wall of the chamber. A pair of detectors outside the chamber and mounted on the sprung mass for movement therewith detects the magnetic fields and thereby the movement of the followers to determine the relative spacing of the sprung and unsprung masses. In a second embodiment the magnetic devices and detectors are outside of the chamber with a follower internal of the chamber adapted to interrupt the magnetic field therebetween to determine the relative spacing of the sprung and unsprung masses.

Abstract: In a system which provides feel-force to the control stick of an aircraft by means of hydraulic pressure, a fault indicating system which responds to excessive differences between desired and actual force in the actuator, only of a polarity in the same direction as concurrent stick motion, to separate pilot induced pressure excesses from force-system faults, is provided with directional sensitivity in the fault-indicating output logic. Excessive pressure errors in either direction of stick travel institute the monitoring of changes in stick position. Changes in stick position of an excessive magnitude are recognized as fault only if they occur in the same direction as the direction of excessive pressure error. A simple analog embodiment utilizes threshold detectors and a track store device; a dedicated-digital embodiment utilizes comparators, registers and a subtractor; and a computer embodiment utilizes a software routine.

Abstract: A vehicle adapted to be selectively operated with or without guide rails with the vehicle including a steerable vehicle axle and at least one nonsteerable vehicle axle. The nonsteerable vehicle axle is mounted so as to be entirely pivotable to a limited extent about a centrally positioned vertically extending pivot axis. At least two longitudinally extending control arms are provided for determining a transverse position of the nonsteerable vehicle axle with the longitudinally extending control arms being constructed so as to be variable in length and at least one of selectively lockable in or releasable from a predetermined length required for an exact transverse positioning of the nonsteerable vehicle axle when the vehicle is operated without guide rails. Each of the longitudinally extending control arms includes at least two doubleacting hydraulic cylinder piston units which are disposed in parallel to a bending resistant guide rod slidably received in a guide bore of a guide housing.

Abstract: A hydraulic seat cushioning device comprising a cylinder body and a piston has a concentric post-like upward projection in the cylinder body with a cylindrical surface in which there are a pressure fluid port and a vent port. An annular valving element closely slidably surrounding the post-like portion covers those ports when in a normal position but uncovers the vent port when above that position and uncovers the pressure fluid port when below it. The piston is so connected with the valving element as to move independently thereof in a lower portion of its stroke, but through the remainder of the piston stroke the valving element is constrained to move with the piston.

Abstract: A system for active compensation of undesired relative movement particularly during loading of cargo comprising a long-periodic acting system for compensation of static loading caused by the load and a short-periodic acting system for active compensation of undesired relative movement of the load relative to a reference value. The long-periodic system includes a compensating cylinder provided with two pistons acting in opposite directions, the cylinder being connected to one or more pressure loaded reservoirs operating pneumatically. The short-periodic system includes at least one hydraulic cylinder and the position of the short-periodic system is determined by measurement of acceleration of the end of the loading crane beam by accelerometers.

Abstract: In a hydraulic circuit (10) fluid is passable from a priority valve (28) through control and lockout valves (30,32) to, for example, a suspension system (27) of a work vehicle (20) or control cylinders of a steering assembly. The lockout valve (32) provides for controllably operating or locking out, for example, the operation of the suspension system (27) where desired. The control valve (30) controllably passes fluid to the suspension system (27), for example, based upon demand created by operation of the system (27). The control valve (30) also delivers a signal to the priority valve (28) for maintaining priority of fluid flow from the priority valve (28) to the suspension system (27). In the circuit (10), the signal is automatically, controllably blocked in response to locking out the operation of the suspension system (27) for preventing the priority valve (28) from maintaining priority fluid flow to the non-operative suspension system (27).

Abstract: Winch especially a ship's winch designed for mooring, hauling, towing and the like. A control system adapted to establish a desired tension in the hawser via the drum of the winch by regulating the power of the drive motor so as to pacify or mitigate peak tensional loads on the hawser. A regulatable transmission arranged between a control member of a control device incorporated in the control system and a movable component selected from the winch drum and its drive shaft to control the control member in a linearly regulatable actuation movement depending upon the movement of the movable component. The transmission is regulatable to an actuation position in which a desired tension is established in the hawser from the winch drum on exposure of a desired length of the hawser.

Abstract: Disclosed is a device for detecting the displacement of a hydraulic cylinder barrel and its piston with a higher degree of accuracy even when a hydraulic cylinder is subjected to severe vibrations.

Abstract: A suction dredger, comprising a vessel and a suspension conveying conduit provided with a pump and having a nozzle suspended by means of at least one cable of a lifting device on the vessel, is improved for preventing breaking of the cable or damage of other dredger parts. To this aim the lifting device comprises a cable length variator having a piston movable in a cylinder, a pick-up system for picking up the travel of the piston, a fluid conduit communicating with the cylinder for supplying and discharging fluid and control circuitry for controlling the supply and discharge of the fluid so in dependence on the travel picked up by the pick-up system, that the piston is pushed backwards into a prescribed stretch.

Abstract: An adjustable hydraulic makeup and control system is provided for supplementing the primary hydraulic flow to overcome leakage and thus be able to maintain a constant pulling load on a drill pipe or other tool in a well hole for an indefinite length of time.

Abstract: A step-by-step controlled servomechanism of the type comprising a drive element movable provided with a plurality of receiver ports, and a fixed distributor to supply said receiver ports and having a number of transmitter ports capable of being connected, in pairs, respectively to the low pressure and to the high pressure, a fixed manifold having a plurality of manifold ports capable of communicating with the chamber of the drive element, all the receiver ports being capable of being made to open in succession into one of said manifold ports, selecting means capable of connecting, in succession by permutation and simultaneously, at least one pair of transmitter ports to the high pressure and to the low pressure, respectively, and at least one manifold port to the chamber of the drive element.

Abstract: This invention relates to apparatus for the control of a weight suspended from a vessel employing a pneumatic suspension system subject to heave action so as to maintain the pressure in the pneumatic system substantially constant during the heave of the vessel as the result of the wave action.

Abstract: A control valve for controlling the supply of pressurized fluid to a working element, such as a pneumatic spring, comprises a housing having a bore comprising first and second bore sections with a smaller diameter middle bore section. A connection for a source of pressurized fluid communicates with the first bore section; an outlet opening with the second bore section; and a working element, such as a pneumatic spring, is fed from the middle bore section. A valve stem is slidable within the middle bore section in response to displacement of the working element, and has a duct therethrough which can interconnect the first and the second bore sections but which can be closed off by a closure member in the first bore section. The closure member can also isolate the middle bore section from the first bore section.

Abstract: Step by step controlled servomechanism of the cylinder-type comprising a drive element movable in a case which it divides into two chambers and provided with a plurality of receiver ports, a distributor adapted to be put in communication with the high pressure and the low pressure and to supply said receiver ports, wherein said distributor is fixed and provided with a number of supply or transmitter ports at least equal to three but independent of the number of receiver ports, the transmitter ports being capable of being connected by permutation, in succession and in pairs, respectively to the low pressure and to the high pressure, the distance between the receiver ports and their length, on the one hand, the distance between the transmitter ports and their length, on the other hand, being such that, by the step by step displacement in one direction of the drive element, on one hand, it is possible to bring each time at least one receiver port between the two transmitter ports of a pair in such position that

Abstract: A pressure balanced hydrostatic slip bearing as shown for use in guiding and restraining a test table which is shaken in longitudinal direction to vibrate or shake test objects, and also which may be shaken in vertical direction. The slip bearing controls lateral position of the table during operation. A second slip bearing applies a constant compressive preload force to one side of the table and the other pressure balanced bearing is a constant displacement bearing positioned on an opposite side of the table to react lateral forces which may be imposed on the table during operation.

Abstract: An adaptive actuator system comprising a rotatable shaft operatively coupled to a torque biasing means for biasing the rotational direction of the shaft, and also operatively coupled to a counter torque developing means for sensing the rotational bias of the shaft and providing a counter torque proportional to the rotational bias.

Abstract: A hydraulic valving mechanism for controlling an object in a normally level position such that upon a shifting of the same from level an actuating mechanism is driven to return the object to the desired level, such valving mechanism including a valve housing with control ports therein with a gravity responsive member therein to open and close selected ones of the ports depending upon the direction the same is shifted from level with the ports being interconnected to a main control valve for shifting of the same to direct fluid to the proper side of the actuating mechanism to return the object to its normal, level position.

Abstract: A heave-compensating device particularly for floating oil drilling rigs incorporates a passive load-supporting system capable of being set to exert a chosen datum load-supporting force and an active force-modifying system operative when the force exerted by the passive load supporting system deviates from the chosen datum force to reduce the deviation. The passive load-supporting system may include a cylinder and piston assembly connected between a fixed support to which said system is connected and the load. The end of the cylinder adjacent the load is connected to a supply of liquid and to one end of a dashpot cylinder containing a piston, the other end of the dashpot cylinder being connected to a supply of compressed gas.