Abstract: A mechanical device comprising, a gear rack having a first point and a second point; at least one piston attached either to said first point or said second point; said piston having an exterior surface and an interior surface; wherein said exterior surface is facing away from said gear rack and wherein said gear rack is attached to said interior surface; said gear rack being gyratingly coupled with an actuator shaft; wherein said gear rack is capable of moving in a substantially linear direction due to a force being applied to said exterior surface or said interior surface; and wherein said actuator shaft rotating due to the said motion of said gear rack; in another embodiment, at least one piston having an interior surface and an exterior surface; said inner side pivotingly mated with a connecting rod; said connecting rod having an opposing point B which is rotationally fastened to a counterbalance; said counterbalance rotating about an actuating shaft; a cylinder chamber having with a top breach housing sai

Abstract: A fluid rotary machine with a decreased footprint and a reduction in the number of parts. The fluid rotary machine has four heads wherein double-headed pistons are disposed inside cylinders in a crisscross arrangement. The rotational balance between rotational parts including the double-headed pistons is achieved only by first and second balance weights which are inserted and incorporated into both ends of a crank shaft coupled eccentrically to a shaft. The shaft is rotated for the double-headed pistons to linearly reciprocate in the cylinders. The fluid rotary machine has rotary valves for switching between the suction and discharge operations of the fluid for each cylinder chamber. The rotary valves are incorporated into a case to be coaxial and integrally rotatable with the shaft.

Abstract: A control system for a trimmer head assembly includes a first arm including a first mowing device, a first cylinder connected to the first arm, a source of fluid in selective communication with the first cylinder via a fluid line, and an accumulator in selective communication with the first cylinder when the first cylinder is not in communication with the source of fluid. The accumulator is adapted to receive fluid from the first cylinder when an external force is applied to the first arm and to deliver fluid to the first cylinder when the external force has been removed from the first arm.

Abstract: In a hydraulic actuator comprising a hydraulic piston, a hydraulic cylinder and a hydraulic pressure source wherein said hydraulic piston has a larger area exposed to pressure on the side of the control chamber than on the side of oil supply chamber of said hydraulic cylinder, wherein said hydraulic piston has, in its outer peripheral part, a slot connecting said oil supply chamber side with the control chamber side in the direction of shaft and the cross sectional area of the slot in the direction of said shaft changes according to the displacement of the hydraulic piston in the direction of its shaft, and the control chamber has a pilot valve, the suction and exhaust valve in a variable valve system of the internal combustion engine are opened and closed by said hydraulic actuator through a coupling and springs for the valve, for variably controlling the opening and closing timing, the opening and closing time, and the lift of the valve, whereby it is possible to provide a variable valve system for internal

Abstract: Apparatus and methods are provided for pumping concrete using a pumping apparatus including first and second drive cylinders, a valve, and a pump. Fluid is delivered into the cylinders from the pump to reciprocate pistons within the cylinders. Pressure within the cylinders is monitored, and a direction of flow of the fluid is switched based upon the pressure within the cylinders. For example, during rod-side operation, the valve is set to deliver fluid into a head side of the cylinders. When the pressure exceeds a predetermined threshold, the valve switches to head-side operation, and fluid is delivered into a rod side of the cylinders. If the pressure falls below the threshold, the valve switches the cylinders back to rod-side operation.

Abstract: A piston-cylinder mechanism includes a cylinder (50) that defines a cylindrical bore (51). Two pistons (52, 53) are disposed within the cylindrical bore, so that a first pressure chamber (57), a second pressure chamber (58) and a third pressure chamber (59) are defined within the cylindrical bore. The first pressure chamber and one of the second and third pressure chambers individually receive a supply of a pressurized fluid. The pressurized fluid is delivered individually from the second pressure chamber and the third pressure chamber to respective external devices (16, 17). A valve (60; 160) is arranged between one of the second pressure chamber and the third pressure chamber and the corresponding external device. The valve is operable to open and close when the one of the second pressure chamber and the third pressure chamber is expanded and contracted, respectively, due to the movement of the pistons.

Abstract: A swing cylinder oscillation control circuit and valve for oscillating booms connects two hydraulic cylinders with a shuttle valve and two check valves to provide the higher cylinder pressure to a fluid inlet and a lower cylinder pressure to a fluid outlet of a fast-opening and a slow-closing check valve. The fast-opening and slow-closing check valve uses a poppet and spring to set a valve opening pressure and uses internal flow connections to a large diameter piston that works with mechanically adjustable piston and poppet strokes to control the time for valve closing.

Abstract: An actuator comprises a cylinder, a first, second and third port, an actuation piston, a control piston and a control spring. The cylinder defines a longitudinal axis and comprises a first and second end. The first port communicates with the first end of the cylinder, the second port communicates with the second end of the cylinder, and the third port communicates with the cylinder between the first and second ends. The actuation piston is disposed in the cylinder and is moveable along the longitudinal axis in a first and second direction. The actuation piston comprises a first and second side. The control piston also is disposed in the cylinder and is moveable along the longitudinal axis in a first and second direction. The control piston comprises a first and second side, with the first side of the control piston facing the second side of the actuation piston. The control spring biases the control piston in at least one of the first and second directions.

Abstract: A wood splitting apparatus has a parting blade and a platen which undergo reciprocating motions in mutually opposite directions by means of a pair of hydraulic cylinders. After the parting blade splits off a portion of a sawn log horizontally, the portion which has been split off is dropped and then pushed by the platen into and through a cutting block provided with a plurality of knives so as to be cut into smaller pieces. The pair of hydraulic cylinders is directly connected by a pipe through which a hydraulic liquid can flow back and forth therebetween and is together controlled by a single valve for power economy. The floor of the cutting block is of an inverted V-shape and the knives are oriented such that the intervals therebetween increase on the downstream side so as to prevent jamming of the apparatus by the wood pieces.

Abstract: An actuating device for automation of a manual transmission of a vehicle has a housing in which a first main piston and a second main piston are slidably supported. A control lever, fixedly connected to the actuator shaft of the manual transmission, is provided to select a gate of the manual transmission. The control lever is positioned between the first and second main pistons. A first valve hydraulically controls and actuates the first main piston by a hydraulic medium. A second valve hydraulically controls and actuates the second main piston by the hydraulic medium.

Abstract: An improved spring brake actuator includes an improved valve housing which incorporates pressure test points into the air supply, and further incorporates an anti-compounding valve. By incorporating the anti-compounding valve and test points directly into the valve manifold, the inventive spring brake actuator reduces the number of separate parts. The anti-compounding valve is operable to insure that there will be no compounding of the braking force.

Abstract: A run-up control for the pressure cheek in a drawing apparatus achieves stoppage times during the run-up phase by having a pressure cylinder with first and second pressure spaces as well as a control piston which is fixed in its position in the control cylinder when the second pressure space is acted upon with pressure. The control piston is fixed in its position by a piston rod, a fixed stop and an adjustable stop. The first pressure space is in a continuous flow connection with a mash pressure space which is reduced when the pressure cheek runs up so that the volume of the second pressure space determines the point in time of the stoppage time in the run-up phase of the pressure cheek.

Abstract: A percussive tool comprising a housing (1) accommodating a movable striker (2) and connected with a power cylinder (6) in which is arranged a striker shank (4) with a gripping mechanism (14) and a drive in the form of a hydraulic cylinder (8). The percussive tool is provided with a control unit having a spool valve means (18) to control a distribution means (19). The spool valve means (18) has a casing (22) and a spool (23) taking two positions in the casing and defining two chambers (25, 26) interconnected through a throttling means (24). One chamber (25) constantly communicates with a discharge line (21), and the other chamber (26) is periodically put in communication with the space of the hydraulic cylinder (8). The spool (23) is spring-loaded with respect to the casing (22) on the side of one chamber (25) and takes in this case its first position.

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: A fluid actuated shift bar housing assembly for a change gear transmission wherein the shift bars are biased to an axially centered neutral position by constant fluid pressure in a constantly pressurized chamber and are selectively axially moved to an axially displaced gear engaged position by selective pressurization of a selectively pressurized chamber. A detent mechanism is provided for retaining the shift bars in the displaced positions thereof, said detent providing a resistance to axial movement of the shift bars having a smaller axial magnitude than the axial centering bias of the constant fluid pressure.

Abstract: An electrohydraulic actuator has a power piston which is controlled from movement between the ends of its travel for performing work by servo control valve. When the actuator is not performing work, the power piston is abutted on one side by a pressure positioned centering piston which prevents the movement in one direction. High pressure fluid operates on the other side of the power piston to prevent movement in the other direction so that the power piston is centered in the cylinder and cannot be moved by external forces.

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.