Abstract: An agricultural implement for cultivating an agricultural work area includes a main frame which is transferable between an operating position and a transfer position. A first subframe is connected to the main frame, and the first subframe is transferable between an operating position and a transfer position. A main frame hydraulic cylinder and a first subframe hydraulic cylinder move the main frame and the first subframe between their corresponding positions. In order to provide correct and repeatable positioning of the first subframe hydraulic cylinder, a volume of a first chamber of the main frame hydraulic cylinder is substantially equal to a volume of the first chamber of the first subframe hydraulic cylinder when the first subframe is in its operating position.

Abstract: A telescopic actuator comprising a cylinder (2) in which a rod (3) is mounted to slide along a sliding axis (X), the actuator including a locking member comprising a locking finger (10) that is movable along a locking direction (Y) that is perpendicular to the sliding axis, between a locking position in which an end (9) of the locking finger (10) is engaged in a groove (8) of the rod in order to lock the rod in position, and a retracted position in which the end of the finger is disengaged from the groove in order to release the rod, a locking indicator (20) being secured to the locking finger to be movable between a position indicating locking when the locking finger is in the locking position, and a position indicating unlocking when the locking finger is in the retracted position, the actuator being characterized in that the locking indicator is secured to the locking finger by a connection (22, 23, 24) suitable for being interrupted in the event of the end of the finger being broken off while the rod is l

Abstract: A vehicle includes a coupling for mounting an implement and a load-controlled hydraulic pump that runs continuously with an engine of the vehicle. The pump draws hydraulic fluid from a low-pressure line region and feeds the hydraulic fluid into a high-pressure line region. The high-pressure line region has a high-pressure connection and the low-pressure line region has a low-pressure connection for supplying the mounted implement. A shutoff valve for blocking the flow of hydraulic fluid to the high-pressure connection is connected upstream of the high-pressure connection in the high-pressure line region.

Abstract: A control device for the position control of a hydraulic cylinder unit has a controller which receives a set and an actual piston position and determines a preliminary manipulated variable based on the difference of the set and actual positions. A linearization unit multiplies the variable with a linearization factor and outputs it to the valve control unit so that the piston is adjusted at an adjustment speed. The linearization unit determines the factor dynamically as a function of the actual piston position and of working pressures that prevail at both piston sides. The linearization factor is determined such that a ratio of the adjustment speed to the difference of the set and actual positions is independent of the actual position and the working pressures. In the specific case where the controller is configured as a P controller, the order of the controller and the linearization unit can be reversed.

Abstract: A jack system provided with a cylinder provided with a first stopper. The jack system also includes: a body hinged about an end of the piston, the body including a second stopper and being able to occupy a first angular position authorizing the extraction of the piston, as well as a second angular position uniquely allowed when the piston occupies a position such that the second stopper is located beyond the first stopper in an extraction position, the body occupying the second position providing the facing of the first and second stoppers; and an electromagnetic attraction/repulsion device designed to provide the displacement of the body from the first position to the second position, and inversely.

Abstract: Between an air source and first and second pressure chambers of a double-acting main cylinder having a length measurement sensor for measuring an acting position of a piston, a first supply solenoid valve and a second supply solenoid valve are connected, respectively, while between the first and second pressure chambers and the atmosphere, a first exhaust solenoid valve and a second exhaust solenoid valve are connected, respectively. When a target acting position of the piston is inputted into a controller, the controller moves the piston to the target acting position so that a position measured by the length measurement sensor agrees with the target position by on-off controlling the solenoid valves. Upon reaching the target position, the piston is stopped and held in the stopped state by confining air within the pressure chambers.

Abstract: The present invention discloses a miniature thermodynamic device that can be constructed using standard micro-fabrication techniques. The device can be used to provide cooling, generate power, compress gases, pump fluids and reduce pressure below ambient (operate as a vacuum pump). Embodiments of the invention relating to the production of a cooling effect and the generation of electrical power, change the thermodynamic state of the system by extracting energy from a pressurized fluid. Energy extraction is attained using an expansion process, which is as nearly isentropic as possible for the appropriately chosen fluid. An isentropic expansion occurs when a compressed gas does work to expand, and in the disclosed embodiments, the gas does work by overcoming either an electrostatic or a magnetic force.

Abstract: A water well recharge throttle valve (1) is configured as a hydraulic actuated flow control device (5) that permits calibrated throttling of water used in Artificial Storage and Recovery (ASR), Salt Water Barrier, Dedicated Recharge and Injection Wells to prevent the free cascading of water and thereby eliminating the entrainment of air which may cause air fouling, bio-fouling, calcite formation with a resultant reduction in permeability of the aquifer.

Abstract: An off-line teaching apparatus includes an operation command-receiving device for receiving an operation command inputted via an input/output port from a key input device or a coordinate input device and successively storing the operation command in a buffer; an operation command-reading device for successively reading the operation command stored in the buffer; an operation command-counting device for counting a number of operation commands stored in the buffer; and a confirmation sound-generating device for generating confirmation sound upon receipt of the operation command by the operation command-receiving device when a counted value obtained by the operation command-counting device is not less than a predetermined number. Accordingly, the operator is informed, in real time, of the fact that the system responds to the input of the operation command from the operator. Thus, it is possible to improve the operability of the off-line teaching.

Abstract: The invention relates to a safety arrangement on hydraulic piston-cylinder units. In particular for monitoring locking cylinders, e.g., of operating tools mounted on a grab bucket boom. A sensor for monitoring the piston position is provided on the piston-cylinder unit and is coupled electrically to a monitoring circuit for triggering an alarm arrangement if the piston is incorrectly positioned. The sensor (3) is coupled to an electrically actuatable locking valve (2) coupled in the monitoring circuit (9) for controlling the hydraulic piston-cylinder unit (1).

Abstract: An axially reciprocable working piston has opposed working surfaces facing opposed working chambers which are intermittently connected to respective cavities pressurized with compressed air. The working piston is connected to opposed seating pistons which cut off the connection between the cavity and working chamber behind the advancing piston and establish the connection in front of the piston, thereby conserving compressed air and storing potential energy for return movement of the piston. In either of two stable positions the working piston is hydraulically latched by fluid admitted to a respective chamber from another chamber through a two-way check valve. The check valve is electronically switched on commend to reverse the flow direction of the hydraulic fluid, thereby initiating movement between opposed stable positions.

Abstract: The present invention provides a pneumatically powered actuator having hydraulic control for both locking and controlling the velocity of an output rod without any sponginess. The invention includes a double-acting pneumatic actuator having a bore, a piston slidably engaged within the bore, and a control rod connected to the piston. The double-acting pneumatic actuator is mounted to a frame. A first double-acting hydraulic actuator having a bore, a piston slidably engaged within the bore, and a follower rod mounted to the piston is mounted to the frame such that the follower rod is fixedly connected to the control rod. The maximum translation of the piston within the bore of the first double-acting hydraulic actuator provides a volumetric displacement V.sub.1. The present invention also includes a second double-acting hydraulic actuator having a bore, a piston slidably engaged within the bore, and an output rod mounted to the piston.

Abstract: An electronically controllable hydraulically powered asymmetrical valve actuating mechanism for use in an internal combustion engine of the type having engine intake and exhaust valves with elongated valve stems is disclosed. The actuator is a bistable electronically controlled hydraulically powered transducer having an armature including a power piston which is reciprocable between first and second positions along with a hydraulic arrangement for powering the armature from a first (engine valve closed) position to a second position. A bistable control valve is operable in one of its stable states to supply high pressure hydraulic fluid to one face of the piston to power the armature and in the other of its stable states to relieve the high pressure fluid from the piston. The mechanism has a compressible resilient arrangement such as a coil spring or a chamber in which air is compressed during motion of the armature from the first position to the second position.

Abstract: An electronically controlled actuator which compresses a fluid thereby storing potential energy as it transitions from a first to a second position is disclosed. The compressed fluid exerts a high force on the actuator and the potential energy is recovered in returning the actuator to the first position. A latching arrangement automatically locks the actuator shaft as it reaches the second position. The latching arrangement is selectively unlocked at the prescribed time to allow the stored potential energy to return the actuator to the first position.

Abstract: The invention relates to a piston and cylinder unit whose piston rod is provided with a rack extending along it. The rack is in mesh with a ring of teeth (such as the teeth of a toothed belt or the teeth of a gear wheel) adapted to revolve about one axis (in the case of a gear wheel) or about at least two axes (in the case of a toothed belt). Such meshing engagement takes place in every position of the piston rod. When the piston rod is moved in the direction of its length the ring of teeth revolves about at least one axis and rotates a means for influencing the motion of the piston rod. Such means may for example be a liquid brake or a synchro transmitter connected with a NC unit controlling the supply of driving fluid to the piston and cylinder unit.

Abstract: A servocylinder (1, 3, 4) with an electric piston end position transmitter is suggested. It is constructed as a piezoelectric converter (17 and 18). By means of applying voltage to the piezoelectric converter (17 and 18) the latter becomes a regulating element which overcomes a force holding the piston (2) in its stroke end position and removes the piston (2) from its position in which the feed line (7 and 8) of the pressure medium is sealed.

Abstract: A hydraulic operating apparatus in which a differential piston is used as a drive unit, and in which the differential piston is driven by applying a high pressure fluid on a large piston face side through a hydraulic pressure control device for controlling the hydraulic pressure, and a high pressure fluid always being applied on the small piston face side. The hydraulic operating apparatus is constructed such that a high pressure fluid is applied concurrently on both piston faces when the differential piston stops at its receded position, and a thrust generated due to the difference between the forces applied on the both piston faces is held in check by a holding device acting on the differential piston or its extension. The differential piston is moved forward upon the removal of the holding force of the holding device, and the piston is moved backward upon the removal of the high pressure fluid on the large piston face side.

Abstract: A non-public hydraulic elevator has three emergency systems isolated from the primary drive system: a control system, a manually activated emergency descent system, and an emergency stop system. A hydraulic brake is provided a primary and emergency brake release pressure supply by the control and manually activated emergency descent systems, respectively. The emergency stop system overrides the control system and the emergency descent system to positionally lock the elevator car. A hydraulic safety-governor system operates during descent to monitor and maintain a controlled descent speed.

Abstract: The invention relates to a hydrostatic steering device having a servomotor connectable to wheels to be steered. The travel limits of the servomotor are sensed with position sensors which function to operate a locking apparatus which mechanically prevents further turning of the steering wheel upon a travel limit being reached in either direction.

Abstract: A high resolution servo actuator is responsive to an electronic control or manual control. An output shaft having fast response and infinite positioning for stroking a manual servo valve on a pump is rotated by hydraulic power. A set of hydraulic working cylinders and centering cylinders are connected through a rack and pinion drive to a shaft. Centering cylinders utilize stop tubes to prevent its pistons from traveling past the center position and applying a constant force to center the shaft. A directional valve controls the flow of hydraulic fluid to the working cylinders for driving the shaft throughout its range of travel. An electrohydraulic servo valve converts the electronic control signal into hydraulic flow to the actuator. Shaft position feedback is developed and connected to the electronic control.

Abstract: A fail-fixed electrohydraulic servosystem in which a variation from a predetermined range of electrical input to the servosystem results in the output of the system being fixed in position. Fixing-in-position is accomplished by either hydraulically or mechanically locking a linkage to the output arm of the servosystem. Provision is also made for controlled drift and manual adjustment of the output after it is fixed in position.

Abstract: The drive comprises an air-operated driving unit imparting either a linear or a rotary motion to the working member of a manipulator and, at the same time, driving the rotor of an electromagnetic brake in accordance with displacement of the working member. For linear movement of the working member, the driving unit comprises an air-operated piston-cylinder actuator and, for rotary movement of the working member, comprises a vane-type air motor. An electronic control system controls the operation of the driving unit and of the electromagnetic brake, and thus the motion of the working member.

Abstract: An impending kickback condition is the operation of a power tool or machine tool system is sensed and used to control or eliminate the kickback. The ability to sense an impending kickback condition can be used in all categories of power driven tools. The change in force applied to the power driven tool or other implement is monitored by measuring the rate of change of speed of the tool or implement, and if the speed is decreasing, the rate of change of speed is compared with a threshold value which may be either preset or variable. If this threshold value is exceeded, an output control signal is generated which inhibits the coupling of power to the tool or other implement and/or applies a brake to stop the tool or implement. In order for power to once again be coupled from the motive power source to the shaft, the start switch must be opened and then reclosed or some other signal provided by the operator or another predetermined condition must be met.

Abstract: A brake cylinder device including a brake piston operable by a spring force to an application position and to a release position in response to an opposing fluid pressure force, and a fluid pressure operable locking device operable responsively to release pressure for locking the piston in the release position and for delaying such locking of the piston in the release position during normal operations to prevent untimely locking-up of the piston.

Abstract: A digitally controllable pneumatic linear actuator in which a moving piston driven by compressed air is initially decelerated by the pressure of compressed air applied to the both sides thereof in the course of its advancing movement toward a predetermined stop position and is then braked by a mechanical brake, thereby obviating failure of precise positioning of the piston due to the compressibility of air. The piston displacement is digitally detected, and the result of detection is fed back to a digital controller.

Abstract: This disclosure relates to a system for protecting pneumatic cylinders and diaphragm valves against failure of both electrical and pneumatic supplies. In the event of a failure of the air supply, the loss of air pressure is detected and all drives are locked in position. The position pneumatic feedback signal from the pneumatic cylinder diaphragm valve is then connected directly to a pneumatic memory. Thus when the air supply recovers, the pneumatic memory will be equal to the instantaneous position of the pneumatic cylinder or diaphragm valve.In the event of an electrical failure, a solenoid valve interrupts the flow of the pneumatic signal from an electropneumatic transducer to the pneumatic memory, so that the air cylinder or valve is directly connected to the pneumatic memory. By selectively energizing a pair of solenoid valves connected to the memory, the operator using an emergency d.c.