Abstract: A stroke-adjusting drive mechanism in which the stroke of a reciprocating member, such as a piston, is adjustable for use in machines such as hydraulic presses and press brakes is disclosed. The apparatus includes a cylinder and piston with a piston rod member which projects outwardly from the cylinder. A restricting valve means is arranged between a chamber of the cylinder defined by the piston member and a hydraulic passage connected with a hydraulic pump. An adjusting member is arranged in the piston rod member so as to be adjustably positioned along the axis thereof and a regulating valve is provided for restricting the flow of hydraulic fluid from the first chamber in response to changes of pressure and the hydraulic passage. By means of the apparatus of the present invention, the stroke length of the piston member can be easily and precisely adjusted as well as stopped at a desired position.

Abstract: The invention relates to a positioner device for positioning the piston and piston rod of a double-acting, pneumatic operating cylinder at a preselected position for setting the position of a device connected thereto, such as the lever of a throttle valve, for example, with the positioner device having a locking device connected to the piston rod which can be controlled by a control valve for securing and maintaining the piston and rod in the selected position, without variance, until deliberately changed.

Abstract: The invention relates to a cushioning device for a piston of a pneumatically operable driving tool which includes a cylinder, wherein a drive piston connected to a driver blade is axially movable; including further a bumper at the lower end of the cylinder and an annular chamber connected to a fluid power reservoir; this chamber is located underneath the piston and is surrounding the driver blade. The annular chamber, created by the piston and a wall, generally parallel to the face of the piston, will be reduced in volume to a certain extent when the wall impacts on the bumper to reduce the noise generated during the driving action.

Abstract: Herein disclosed is a hydraulic actuator which comprises an outer cylinder; an inner cylinder attached at its one end to the axial inner one end of the outer cylinder in coaxial relation with the outer cylinder to define an annular gap between the outer and inner cylinders; a piston having a hollow bore axially extending from its one end to the other end and closed at the other end and slidably received in the annular gap; and a locking mechanism temporarily locking the piston with the outer cylinder upon the farthest movement of the piston to the other end thereof; the locking mechanism including a locking member coupled with one end portion of the piston and which is radially movable, a ram resiliently received in the other end of the inner cylinder and having an inclined stepped portion and a hollow bore axially extending from its one end to the other end and opened at the other end, and an annular locking groove formed at the inner periphery of the other end of the outer cylinder, whereby the locking memb

Abstract: A novel electropneumatic servoactuator utilizing a fluid pressure control signal chamber and a duty-cycle control valve alternating between a fluid supply pressure port means and port means venting the chamber to the atmosphere and controlling fluid pressure in the chamber. The control valve is driven by electromagnetic means comprising a coil responsive to an electrical input signal. Pressure responsive actuator means moves in response to the chamber pressure level for providing a mechanical position output. Feedback means senses movement of the actuator means and throttles the fluid flow in one of said port means. In another aspect of the invention, an auxiliary dump release valve armature means is also driven by the coil in preferably magnetic series circuit arrangement with the control valve and coil for rapidly porting the control chamber to the atmosphere for emergency release.

Abstract: A hydraulically actuated control valve normally includes a hydraulic cylinder which has an internal piston connected through a shaft to the actuating mechanism in the control valve. Ports are provided on each side of the piston through which fluid flows to move the piston axially inside the cylinder. The piston can be controlled electrically by an electro-hydraulic servo-controlled valve which includes an electrical input, a mechanical feedback input, and first and second outputs. The outputs are connected to the two ports in the cylinder, a mechanical feedback is coupled to the shaft and the mechanical feedback input of the control valve, and an electrical circuit is coupled to the electrical input of the servo-controlled valve to signal the hydraulic portion of the valve to either move the shaft in a manner to close the valve or move the shaft in a manner to open the valve.

Abstract: A crimping machine for crimping a metal end fitting onto a flexible hose includes a stationary socket, a crimping die arranged in the socket for axial movement, and a hydraulic actuator. A valve member is provided in a fluid flow passage leading from a pump to the actuator. The distance between the valve member and a piston of the actuator is precisely controlled to control the axial movement of the crimping die relative to the socket.

Abstract: The lower draft link of a tractor three-point hitch includes a sensor to sense draft loads imposed on the draft link by an earth-working implement. Variations in the draft load cause variations in the pressure of the fluid in the sensor from a preselected pressure. A pilot-operated, load control valve is connected to the sensor and is shiftable in response to pressure above and below the preselected pressure to actuate a control mechanism. The control mechanism actuates a direction control valve for directing fluid to and from a hydraulic lift cylinder for respectively raising and lowering the draft link to adjust the implement so as to maintain the preselected pressure and thus maintain the desired draft load.

Abstract: A high-speed steam admission poppet valve structure in a steam engine employs a low-inertia valve element spring-biased into seated position in a valve seat in the end wall of a cylinder and employs a valve lifter member fixed to the face of the associated piston for cyclically unseating the valve element, the lifter member and the valve element having cooperable engageable surfaces of conforming configuration which are maintained in engagement in both the unseating and seating of the valve element for maintaining the sealing surface of the valve element both parallel to and centered in relation to the valve seat in the seating of the valve element.The clearance volume of the cylinder may be adjusted manually or automatically to regulate the power output and efficiency of the engine.

Abstract: The invention relates to a servo assembly having a stationary part including a housing, a movable member and a servo motor. Of primary interest is the stopping mechanism which includes a stop unit on the movable member and two pressure operated, vertically reciprocal stop members mounted in the housing. Two hydraulic circuits are provided with a first circuit for the two stop members and the second circuit for the servo motor. Throttle valving for the first circuit is provided between the two stop members and the housing. Prior to reaching a stopping position the stop unit on the movable member actuates a switch which relieves the pressure in the first circuit and causes one of the stop members to descend to an intermediate position where throttling occurs and the other stop member to descend to a final position where throttling may or may not occur. The throttling causes substantial braking of the movable member during a short distance of travel just prior to the stopping position being reached.

Abstract: A pneumatic impact device comprising a housing, a drive piston and a piston rod. At the forward end of the piston rod there is attached a tool intended for metal working like punching, cropping or forging. The housing contains a drive chamber, an air charge chamber, a reverse chamber and a retard chamber. The piston rod is provided with two forward-facing, annular shoulders one of which constitutes a reverse piston for working in the reverse chamber and the other a retard piston for working in the retard chamber. For being protected from impact strains, the drive piston is longitudinally displaceable relative to the piston rod. During the working strokes, the drive piston cooperates with a backwardly facing shoulder on the piston rod, but just before the latter reaches the point where the tool hits the billet to be worked, the drive piston is stopped in the drive chamber and is thereby separated from the piston rod shoulder.

Abstract: The lower draft link of a tractor three-point hitch includes a sensor to sense draft loads imposed on the draft link by an earth-working implement. Variations in the draft load cause variations in the pressure of the fluid in the sensor from a preselected pressure. A pilot-operated, load control valve is connected to the sensor and is shiftable in response to pressure above and below the preselected pressure to actuate a control mechanism. The control mechanism actuates a direction control valve for directing fluid to and from a hydraulic lift cylinder for respectively raising and lowering the draft link to adjust the implement so as to maintain the preselected pressure and thus maintain the desired draft load.

Abstract: A positioning apparatus includes a master hydraulic positioning cylinder having a relatively long stroke capability and a train of additively connected, short-stroke pneumatic control cylinders for controlling the length of stroke of the master cylinder and thus the positioning of a variable-position tool such as a band saw. One end of the cylinder train is connected by a feedback rod to an extensible portion of the master cylinder. A connecting rod connects the opposite end of the train directly to the spool of a three-position servo valve which controls the flow of hydraulic fluid to and from opposite sides of the master cylinder. When air pressure is admitted to a selected side of a selected control cylinder, at least a portion of the train shifts initially in a direction to move the servo valve to an operating position to begin stroking the master cylinder in a desired direction.