Abstract: The invention relates to a pneumatic drive, comprising a pneumatic drive unit (1), which has a piston (3) that can be moved between a first position and a second position. The piston is accelerated and braked by means of compressed air, which is fed to or led away from the pneumatic drive unit by means of valve arrangements (8, 9) having distribution valves (16, 17, 21, 22). In at least one distribution valve (17, 22), a damping throttle (20, 25) is provided, which has a differential pressure piston (28), which can be moved as a function of the compression pressure, whereby the free throttle cross-section (49) through which the compressed air flows can be changed as a function of the compression pressure.

Abstract: A brake actuator includes an actuator body, a piston held in the actuator body, and an actuator rod coupled to the piston and coupleable to a brake to actuate the brake. A method of operating the brake actuator includes maintaining a first fluid pressure of a first fluid against a first side of the piston to urge the piston in a brake-actuating direction, and controlling a second fluid pressure of a second fluid against a second side of the piston opposite the first side of the piston to move the piston controllably in a brake-releasing direction. A brake system including the brake actuator is also disclosed.

Abstract: A positioner (102) for controlling a fluid operated actuator (101) including a first fluid chamber (109) and a second fluid chamber (110) is provided. The positioner (102) comprises a first fluid conduit (105) coupled to the first fluid chamber (109). The positioner (102) also comprises a second fluid conduit (106) coupled to the second fluid chamber (110). A differential pressure controller (240) provided in the positioner (102) is adapted to control a fluid supply to the first and second fluid conduits (105, 106) based on a differential pressure between the first and second fluid chamber (109, 110).

Abstract: A pneumatic cylinder system has a pneumatic supply at a first predetermined pneumatic pressure. A double acting cylinder is operably connected to the pneumatic supply and with a piston reciprocatingly mounted inside for retraction and extension of a piston arm connected to the piston. A high pressure pneumatic reserve chamber stores pneumatic reserve at a second predetermined pneumatic pressure that is higher than the first predetermined pressure. The high pressure pneumatic reserve chamber is operably connected to the double acting cylinder through a valve device such that when the pneumatic supply falls below a third predetermined pressure below the first predetermined pressure, the valve device opens communication between the high pressure pneumatic reserve chamber to a selected side of the double acting cylinder to selectively retract or extend the piston and the attached piston arm.

Abstract: An actuator in which overshooting has been reduced is provided. A cylinder is divided by a piston to provide first and second chambers, and first and second control valves 41, 43, which adjust fluid pressure supply to respective chambers in a non-step manner, and first and second discharge valves 42, 44, which control outflow of fluid from the first and second chambers, are provided. A first control device carries out feedback control of pressure to be supplied to the first or second chamber such that a difference between a target position of the piston and a detected position of the piston becomes smaller. A second control device carries out differential-preceding PD control to bias pressure to be commonly supplied to the first and second chambers such that the difference between the target position of the piston and the detected position of the piston becomes smaller.

Abstract: In various embodiments, pneumatic cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the pneumatic cylinder assemblies during expansion or compression of a gas.

Abstract: Between an air source and a first pressure chamber of a double-acting main cylinder having a length measurement sensor for measuring an acting position of a piston, a supply solenoid valve is connected; between the first pressure chamber and the atmosphere, an exhaust solenoid valve is connected; and between a second pressure chamber and the air source, a stop solenoid valve is connected. 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: An improved, modular, internally shifting, double acting linear fluid actuator system which is adapted to be driven by liquid, air stream, steam, or gas, (collectively referenced as fluid medium.) The present invention is comprised of three core modules and two attachment mechanisms: a Control Module, two Canister Modules, and Canister Adjustment Plates. The Control Module receives pressurized fluid medium, internally shifts the fluid medium flow into and out of Canister Modules, and exhausts depressurized fluid medium. The Canister Modules perform the work for each actuator application, and are attached to the Control Module by Canister Adjustment Plates at each end of the Control Module, which allows attachment to different diameter canister modules simultaneously. The Canister Modules may operate at different pressures, different volumes, or perform different applications simultaneously.

Abstract: A pressure spike modulator for engagement to the cylinders of an internal combustion engine. The device provides for adjustment of engine cylinder pressures using a reciprocating piston which provides a temporary increase in engine combustion chamber volume. Pressure from combustion chamber gases is communicated by the device back into the combustion chamber during the downstroke of the engine piston. Engine compression and peak combustion pressure may be modulated by adjusting pressure supplied to the device to resist incoming engine gases. Fuels for the attached engine may thereby be varied or substituted by adjusting the engine peak pressure and compression to one adequate for the chosen fuel.

Abstract: A system for handling gates and the like including a dual-effect hydraulic actuator with a stem traversing one of its chambers and a supply circuit controlled with oil which alternately moves the oil between the actuator chambers for an ‘opening’ or ‘closing’ movement. The circuit includes a pump for transfer of the oil between the chambers through piloted locking one-way valves, an oil tank and two one-way suction valves each connected between the tank and one of the two sides of the pump for allowing suction from the tank of the lacking oil. The suction valve connected from the side of the pump opposite the actuator chamber not traversed by the stem is a one-way valve controlled in such a manner as to open thanks to an overpressure on the hydraulic circuit branch which is for supply of the actuator chamber traversed by the stem. In this manner the oil in excess during movement of the actuator which is caused by transfer of the oil from the stemless chamber to the chamber with stem is dumped into the tank.

Abstract: An actuator (100) for actuating an onboard device (200) on a sailboat (300), comprises: a piston (2) slidably mounted within a cylinder (1) and movable between a first operating position, in which the piston is at a first end portion (3a) of the cylinder (1), and a second operating position, in which the piston is at a second end portion (3b) of the cylinder (1); hydraulic means (101, 15) for supplying a pressurised working fluid at the first end portion (3a) of the cylinder (1), this fluid being adapted to cause the piston (2) to move from the first operating position to the second operating position; pneumatic means for supplying (102, 11) a pressurised gas at the second end portion (3b) of the cylinder, this gas being adapted to cause the piston (2) to move from the second operating position to the first operating position.

Abstract: A wholly air-controlled impact mechanism invented for creating a more compact and powerful pneumatic wrench comprises a flying hammer, a pressure impulse generator and a pressure container containing the hammer and the generator. The main part of the flying hammer is a flywheel with 2 cavities and a number of air passages. A pilot valve and an impact pin are fitted in the cavities. The impact pin rests in its cavity during energy-accumulation phase and stretches out rapidly from the flywheel to finish an impact during impact phase. The generator transmits pressure impulse periodically, affecting the differential pressure acting on the pilot valve. The higher the differential pressure, the greater the impact torque developed. The unique design of the air passages of present invention results in a very reliable, powerful and durable energy-accumulating pneumatic wrench. Its production cost is much lower due to simplicity of its configuration.

Abstract: An actuation arrangement for displaced components on vehicles, particularly trunk lids, convertible tops, engine hoods or the like, includes at least one supply line for the pressurized medium and one essentially non-pressure connection line to a reservoir for the working medium or a pump arrangement being functionally of the same kind, at least one preferably hydraulic working cylinder, and at least one control valve controlling the supply of a working medium in at least one working chamber of the working cylinder.

Abstract: Earthmoving machines are often provided with quick coupling devices that allow them to change work implements in a relatively rapid fashion when compared to changing conventionally mounted implements. A locking system between the machine linkage and the implement is positioned between the components and includes a hydraulic system which continually applies pressurized fluid to the locking system.

Abstract: In a hydraulic operating mechanism for a convertible top, a pressure sensor (12) is incorporated into a common pressure circuit (P) of the hydraulic cylinders (1 through 4) and connected with a control unit which is connected to the switching elements (V1 through V4) of the hydraulic cylinders (1 through 4), and its output signal in relation to time, together with the preset switching sequences of the individual switching elements (V1 through V4), serves to control the end positions of the individual hydraulic cylinders (1 through 4). The control can thus be incorporated in the operating mechanism without expensive separate end position switches at each hydraulic cylinder (1 through 4) or appurtenant actuation element, simplifying the overall design.

Abstract: A cylinder apparatus and a method of controlling the same allow an object to be moved at high speed and provide a decelerating force that can be changed with ease in conformity with the type of object. The apparatus includes a cylinder, a piston, an air supply source, a first pressure regulator for feeding compressed air of a first pressure into one chamber of the cylinder, a second pressure regulator for feeding compressed air of a second pressure into a second chamber of the cylinder, a first solenoid valve, a second solenoid valve, a deceleration-position sensor for sensing a position at which the piston begins deceleration, a stopping-position sensor for sensing that the piston is situated at an end of the cylinder, and controller for controlling the first and second solenoid valves.

Abstract: A gas cylinder control system for use with machine systems such as die stamping systems that includes at least one gaseous fluid cylinder associated with the machine system, gaseous intensifier control cylinder normally operated in timed relation to the gaseous cylinder and a passage providing communication between the gaseous cylinder and the gaseous intensifier control cylinder. The gaseous intensifier cylinder operates at substantially higher pressure than the die cylinder. A normally closed control valve is provided in the passage and is operable to open the passage in time relation to the operation of the machine system in order to apply the higher gaseous pressure of the gaseous intensifier cylinder to the gaseous cylinder and lock the gaseous cylinder and prevent it from moving until the control valve is actuated to close the passage thereby providing a predetermined time delay.

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 fluid apparatus includes a pneumatic cylinder having a main body, a piston, and a hollow rod. A ball screw shaft engaged with a ball nut fixed to the piston is rotatably and axially unmovably mounted in the cylinder and extends in the hollow rod. A magnetic brake for braking the ball screw shaft is fixed to an end portion of the main body of the cylinder. The number of revolutions of the ball screw shaft is detected and outputted in a signal form by a rotary encoder. A primary solenoid controlled valve reciprocates the piston by connecting a pressure source either to a first or second port of the cyliner, and secondary solenoid controlled valves connect a pressure source either to a first braking pressure port or to a second braking pressure port.

Abstract: A regulator arrangement (14) for a servo system (10) having a first stage valve spool piston (44) for developing a primary operational fluid (P.sub.c) and a second stage valve spool piston (70) for developing secondary operational fluid P.sub.cr having a constant fluid pressure. A control valve (109) selectively connects a first chamber (100) of a cylinder housing bore to either the primary operational fluid pressure P.sub.c or a reference fluid pressure P.sub.B to develop a fluid pressure P.sub.x in first chamber (100) while a second chamber (102) is connected to the secondary operational fluid (P.sub.cr). A load piston (96) responds to a pressure differential (P.sub.x -P.sub.cr) by moving to either expand or contract the second chamber (102) and produce a fluid pressure (P.sub.crx) in the secondary operational fluid. The fluid pressure P.sub.crx is communicated to the second valve piston (70) to correspondingly allow either additional primary fluid (P.sub.

Abstract: A method and device are provided for detecting a fluid flow rate, said device comprising a body in which is formed a passage for the fluid, said passage comprising at least two cross sections of different values, a piston having two faces cooperating with the housing, said piston defining with said housing two zones situated on each side of the two faces of said piston, means for returning said piston to a first position or rest position, each of said zones being substantially at the same pressure as said passage at the level of one of the two cross sections.

Abstract: A hydraulic pile driver including a housing having an impact weight mounted therein for reciprocating movement, the impact weight being fastened to a piston movable in a cylinder, a supply source for liquid under pressure, a supply conduit communicating with the supply source, a liquid discharge conduit, a control valve for alternatively connecting the supply and discharge conduits to a cylinder chamber at one side of the piston, whereby the piston can be moved by the liquid under pressure in a direction opposite to the direction of movement of the impact weight during the work stroke, the cylinder chamber during the work stroke of the impact weight being connected to the liquid discharge conduit. The piston at the side remote from the cylinder chamber is loaded by a second pressure medium, the overpressure of the second pressure medium being low with respect to the liquid pressure in the cylinder chamber prior to the working stroke, the overpressure being independent of the liquid pressure.

Abstract: A spool valve for use in a hydraulic ram includes a piston journalled for axial movement within a cylinder under the influence of a fluid fed under pressure to the cylinder. The spool valve is journalled within a valve block closing an end of the cylinder through which passes a piston rod. The valve is biased from one position to another by means of differential areas of a circumferential groove around the spool and by applying fluid to a chamber at one end of the spool.

Abstract: Hydraulic fluid pressure moves a piston (22) against a body of incompressible fluid (14), compressing a spring (42). The pressure is released, and the force of the stored energy in the spring (42) is transmitted to the piston (22) by the body of fluid (14) and drives the piston (22) through its power stroke. The fluid (14) is vented to an outlet (8) before the piston (22) reaches the end of its power stroke, removing the force from the piston (22) and allowing it to free travel through the remainder of the stroke. When the motor (2) is operating and the load is removed from the piston (22), the hydraulic fluid inlet (10) is short-circuited to the outlet (8) and the motor (2) automatically shuts off.

Abstract: An actuator output member (11) is angularly deflectable by two opposed, tangentially movable, pressure transmitting members (7, 8), each responsive to the pressure drop developed across two respective flow restrictors (1, 2) serially connected in a fluid circuit. Deflection is achieved by variation of one or both of the flow restrictors. In a fast response arrangement the fluid is electroviscous and the flow restrictors electrically variable.

Abstract: This invention pertains to a hydraulic reciprocating device having a housing and a piston in the housing. The piston has a first and second surface, and a means for intermittently communicating the first surface of the piston with a hydraulic pressure source. Also provided is a means for continuously communicating the second surface of the piston with pressurized fluid such as pneumatic fluid. The piston moves in a first direction when the hydraulic pressure source communicates with the first surface of the piston and the piston moves in a second direction when the hydraulic pressure source does not communicate with the first surface of the piston.

Abstract: Hydraulic fluid pressure moves a piston (22) against a body of incompressible fluid (14), compressing a spring (42). The pressure is released, and the force of the stored energy in the spring (42) is transmitted to the piston (22) by the body of fluid (14) and drives the piston (22) through its power stroke. The fluid (14) is vented to an outlet (8) before the piston (22) reaches the end of its power stroke, removing the force from the piston (22) and allowing it to free travel through the remainder of the stroke. When the motor (2) is operating and the load is removed from the piston (22), the hydraulic fluid inlet (10) is short-circuited to the outlet (8) and the motor (2) automatically shuts off.

Abstract: A cyclic or periodic event timing system for use in conjunction with a pressure fluid control circuit includes a cylinder and piston type actuator comprising a differential area piston which is exposed to fluid pressure from a flow conduit on opposite sides of a flow restricting orifice in the conduit or a branch portion thereof. The actuator piston includes a rod portion which is extended in one direction in response to an unbalanced pressure force on the piston. On the extension stroke, the actuator opens a valve to effect flow in the conduit resulting in a reduction in pressure which is sensed in the cylinder chamber exposed to the larger piston fluid area. The actuator piston then returns to an initial retracted position in response to an unbalanced pressure force.

Abstract: A hydraulic percussion machine, comprising a body carrying hydraulic passages and valves, and having a gas-filled, hydraulic pressure accumulator for storing the stroke energy which accelerates a piston to strike against a tool. The percussion machine has a separate hydraulic stroke standardizing circuit by action of which the piston stroke is independent of the liquid pressure in the high pressure line supplying the machine and of the volumetric flow.

Abstract: An all-hydraulic impactor for percussion tools and the like embodying an oil accumulator and an annular sleeve valve. Hydraulic fluid is initially supplied to the accumulator at full supply pressure and is then charged, for example, to three times the supply pressure by a differential piston arrangement. The impactor of the invention minimizes the required volume of the accumulator.

Abstract: A hammer or impactor apparatus including improved motive fluid means cooperable with spring bias means to reciprocably drive a hammer element and an improved process of hammer cycling achieved thereby.

Abstract: An impactor apparatus including novel means for actuation of a motive fluid flow control valve or comparable motive fluid control means.

Abstract: Device for generating acoustic waves by implosion in a fluid medium comprising fluid-operated means to move a piston, having one end face in contact with said fluid, from a retracted position in the enclosure to a spaced apart position of maximum extension towards the exterior of the enclosure or vice versa and intermittent locking means for maintaining the piston at its spaced apart position, said fluid-operated means being actuated by two sources of fluid at different pressures, one of which is said fluid medium and the other a source of lower pressure.

Abstract: A method of operating an hydraulic power system having a piston with opposing piston heads reciprocally mounted in opposing piston chambers, the piston being directionally responsive to a pair of control valves adapted to be sequentially opened and closed to actuate the 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 piston, a condition being established in which the piston is at one end of its stroke and a first of the piston heads is under relatively high pressure and the other under relatively nominal pressure, the piston being driven to the opposite end of its stroke by first relieving the high pressure on the first of the piston heads to a nominal level and thereafter rapidly increasing the fluid pressure on the other of the piston heads, the piston and control valves working at all times against solid columns of fluid under controlled positive pressures.

Abstract: A column including a cylinder, a piston axially slidable in the cylinder cavity, a piston rod axially projecting from the cylinder, and a valve permitting selective communication between the two compartments of the cylinder cavity separated by the piston for flow of fluid between the compartments is additionally provided with a helical compression spring coiled about the piston rod and impeding axial movement of the piston on the piston rod in one direction, movement in the other direction being limited by a radial abutment flange on the piston rod. The spring favorably affects the comfort of a chair whose seat is mounted on the column.

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.

Abstract: A pressure medium servo-motor, especially for servo-steering systems, in which a working piston operating in a working cylinder is provided with a piston pressure surface actuatable by the pressure in one working pressure chamber of the working cylinder for producing a servo-force directed in the sense of the relative movement of the working piston with respect to the working cylinder; the piston pressure surface of the working piston is thereby reduced with respect to the reference value fulfilling the equilibrium condition of the piston pressure forces in the neutral position of the working piston, by a reducing piston which includes a pressure disengaging surface actuatable by the pressure in the working pressure chamber and a relief pressure surface actuatable by the pressure in a relief pressure chamber.

Abstract: A hammer and more particularly a fluid operable hammer wherein alternating impetus provided by pressurized liquid and gas means actuates a reciprocable hammer piston to generate repetitive impact loads.

Abstract: In a percussion tool a means is provided for delaying the manifestation, on a valve means sensitive to such change in pressure, of a change in pressure of the fluid applied to the hammer piston at one end thereof and which drives such hammer piston in its working stroke, the valve means being that means which serves to control the inlet and exhaust parts of the fluid circuit which applies pressure to the other end of the piston.

Abstract: A pneumatically buffered drive system is provided which quickly moves a movable member, such as a press safety curtain or press bolster, a predetermined length in three sequential speed stages to prevent maximum acceleration from occurring at the end of the predetermined length. The movable member is coupled to a differential pressure piston which is initially pressurized on only one side of the piston to initiate movement. After traversing approximately half the predetermined length both sides of the piston are pressurized to decelerate the piston during the member movement for approximately the next third of the predetermined length. The remaining length is traversed with the decelerating pressure being vented to positively finish the motion along the predetermined path. In vertical moving members having significant mass such as press safety curtains, a higher pressure is used to decelerate the piston than the pressure used to drive the piston.

Abstract: A hydraulic impact tool wherein hydraulic power is used to lift a ram against a bias to store energy and wherein the ram then is permitted to accelerate toward an impliment to which it imparts energy upon impact. A reciprocating cylindrical sleeve slidable about the ram is arranged to control the hydraulic fluid. The sleeve is initially carried in each direction by the ram and is shifted relative to the ram by hydraulic power.