Abstract: A hydrostatic module is disclosed, including a pair of shafts rotatably supported by a frame. Two yokes are pivotally mounted on the frame, each having complimentary surfaces to the other yoke and to the frame, minimizing the space occupied by the yokes. Stop means are provided on the yokes and on the frame to limit the pivotal movement of the yokes. A hydrostatic power unit is carried by each yoke, each connected to one of the shafts. A control system, having a single piece control housing containing servo pistons, pivots the yokes. The servo pistons independently determine the orientation of the yokes. A single piece fluid control porting plate is secured to the control housing to route hydraulic fluid to multiple locations within the control housing. A fluid manifold serves as a main structural element, with intimate proximity between the manifold and the control housing allowing simplified fluid exchange therebetween.

Abstract: The invention concerns a fail-safe valve having a valve element, and a control motor being connected with the valve element via a driveline. It is endeavoured to ensure the tightness of the refrigeration system in a simple manner. For this purpose, it is ensured that the valve element is located inside and the control motor outside a closed valve housing, that the drive line has a magnetic coupling, which acts through the housing, and that the valve element is pressure-released. In addition, a resetting device is provided that causes the valve element to be returned to a predetermined position upon the undesired cessation of control motor operation.

Abstract: A valve member includes an axially movable spool valve rotatably mounted in the valve member to cause the way that fluid is communicated between the inlet and outlet ports of the device and the volume chambers thereof. An outer surface of the spool has a configuration to react to fluid pressure to effect the timing between the gear set and the valving of valve member and that the timing therebetween will be adjusted when the spool valve is moved axially. A valve actuator comprising a spring loaded plunger controlled by fluid pressure at the inlet and outlet ports is in physical contact with one end of the valve spool.

Abstract: A hydraulic steering arrangement includes a steering valve, a steering motor, connected with a high-pressure connection and a low-pressure connection via the steering valve, and with a steering unit, connected via the steering valve with a pilot pressure valve, whose outlet is connected with the low-pressure connection. It is endeavoured to improve the steering behaviour. For this purpose, the pilot pressure valve is opened, before the steering valve creates a connection between the high-pressure connection and the steering motor.

Abstract: There is described a pressure regulating valve for a refrigerating plant, having a slider member that can be moved relative to a guide by means of a drive device, with variable throttle resistance being created between the guide and the slider member. The purpose of such a valve is to be able to control refrigerant over a relatively large throughput range, and the valve should be able to be manufactured inexpensively. For that purpose, the slider member and the guide co-operate in two sections of their movement relative to one another according to different valve principles.

Abstract: A transmission has an HMT which is in parallel with an HST both driving two planetaries which are used for forward/reverse and for differential steer. A two or three mode HMT is created by having a first HST in parallel with two or three mechanical power paths defined by separate clutches. One clutch has a speed reversing gear to produce reverse output speed. A four-element planetary sums the parallel flow and delivers variable speed and torque to two output shafts. The differential steer is created by two planetaries connected with the outputs of the HMT and a second HST. The planetaries have a speed reversing gear on one power path connection. The second HST controls the differential speed between the output shafts by adding speed to one and subtracting speed from the other.

Abstract: A swing speed compensation device is provided for use with a flow sharing hydraulic system. The present invention is mounted within the metering spool of a flow sharing valve and includes a poppet that is attached to a spring retainer. The spring retainer encases a compression spring which pushes against a plug and has a drain hole that, depending upon the position of the spring retainer and poppet combination, can vent excess pressure within the present invention to a hydraulic pump tank. When a flow sharing hydraulic system starts or stops, there is a rush in the fluid flow that can cause a spike in the system pressure. The present invention absorbs this pressure spike, allowing for the fluid flow to gradually increase or decrease as the system starts or stops.

Abstract: A hydraulic power unit in a housing has a power shaft associated with the power unit. A transducer adapted for measuring torque is mounted in the housing. A stationary portion of the transducer is mounted in non-contact relation to the shaft. A method for measuring torque in the power unit involves placing the transducer in the position described.

Abstract: A cooling medium compressor arrangement is comprised of a compressor, a control mechanism electrically connected with the compressor, and a gas sensor, and the safety of the arrangement is improved by arranging the control mechanism and the gas sensor in a common housing.

Abstract: A fixed displacement pump includes a housing having a cavity, an inlet, and an end cap with alignment portions therein. A cam ring pivotally associated within the cavity includes adjustment portions. The cam ring is aligned in a fixed position via a pin inserted through both a select adjustment portion and a corresponding alignment portion. The adjustment portion selected determines both rotational direction and displacement of the pump. The cam ring also includes recesses positioned adjacent the inlet to facilitate porting of fluid through the pump. A rotor mounted within the cam ring includes roller slots having groove segments. The groove segments are positioned in an arcuate arrangement about the rotor to facilitate porting of fluid through the pump. The rotor also includes undercut portions positioned between the roller slots in an arcuate arrangement on an outer edge of the rotor to facilitate porting of fluid through the pump.

Abstract: A hydraulic spool valve is provided in which two inlet bores and an outlet bore lead into a housing. A spool-valve piston which is under the influence of compression springs on both sides can be displaced longitudinally in the housing. When a difference in pressure of the hydraulic fluid in the inlet bores occurs, the inlet bore which conducts the lower pressure in each case is connected to the outlet bore. The two compression springs are pre-stressed and have an additional expansion path. During the displacement of the spool-valve piston from a neutral central position into an extended intermediate position, the two compression springs therefore remain in operative connection with the spool-valve piston, in which case the spring forces counterbalance each other until the intermediate position is reached.

Abstract: A selectable detent relief valve of this invention is used to operate a hydraulic detent mechanism on a manually operated spool valve. This design has three modes of operation, no-detent, continuous detent and kick-out detent. The no-detent position allows flow to pass through the relief valve, from a first port to a second port and bypass the relief function. The pressure created, disengages the detent mechanism in the spool valve. The spool always returns to neutral position as long as pressure is present. The continuous detent position blocks the flow from a first port to a second port. The kick-out detent position allows flow to pass from the first port to the second port to override (kick-out) the detent mechanism in the spool when the pressure is greater than 2600 psi.

Abstract: A hydraulic valve system (1) has a supply connection arrangement, having a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement, having two working connections (A, B), which can be connected with a hydraulic motor (2), and a directional valve (4) between the supply connection arrangement (P, T) and the working connection arrangement (A, B), which is connected with the working connection arrangement (A, B) via working lines (17, 18), in which are arranged check valves (21, 22), which can be opened by means of pressure.

Abstract: A hydraulic steering system (1) with a supply connection arrangement, having a high-pressure connection (P) and a low-pressure connection (T), and with a working connection arrangement (L, R), a directional valve (2) and a metering pump unit (3, 4) being arranged between the supply connection arrangement and the working connection arrangement, the metering pump arrangement having at least two hydraulically parallel-connected and mechanically parallel-operated metering pumps (3, 4) with a shut-off valve (6) in a hydraulic connection between the two metering pumps (3, 4), said shut-off valve (6) having a return spring (16) and a first control inlet (15) that is connected with the high-pressure connection (P).

Abstract: A method of making a cylinder block for a rotatable hydrostatic power member by separating the cylinder block into its four geometries and joining them together. The geometries include a base plate having a center opening and a arcuate kidney-shaped openings uniformly spaced radially around the center opening. The second geometrical item is a grooved drive shaft that fits into the center opening of the base plate. The third member is a group of tubular bore elements that fit in the base plate and mate with the drive shaft. The final member is a torque ring that matingly fits over the tubular piston bore elements.

Abstract: A decoupled check-relief valve for use in a hydraulic fluid circuit is provided that has a cylindrical guide housing which travels during the check function of the valve. The cylindrical guide housing has a clearance parameter, allowing for the selection of an optimal check response time. A dampening disk is provided inside the cylindrical guide housing, traveling within the guide during the relief function of the valve. The dampening disk has a separate clearance parameter, allowing for the selection of an optimal dampening capacity and fluid circuit stability. As such, the check and relief clearance parameters are independent of each other to allow both the check and relief functions of the valve to be optimized.

Abstract: The invention concerns a driving device, particularly a lifting device for a working vehicle, with a hydraulic drive, in the form of a motor with a first connection and a second connection, a pump, a control valve arrangement between the pump and the drive, and an operating device with at least one operating element with a setting area, with which at least one parameter of the drive can be set. It is endeavoured to provide a simple manner of extending the functionality of the lifting device. For this purpose, it is ensured that the control valve arrangement is optionally controlling the drive to be single-acting or double-acting and the setting area has a first section, in which the drive is controlled to be single-acting and a second section, in which the drive is controlled to be double-acting.

Abstract: The invention concerns a cooling ceiling installation with at least one heat exchanger, a valve (3), which controls the flow of a heat transfer medium through the heat exchanger and a mechanical control device (4), and a monitoring device (6).

Abstract: The invention concerns a fully hydraulic steering with a steering member, a steering unit that can be activated by the steering member, said steering unit comprising a supply connection arrangement (P, T) with a pressure connection (P) and a tank connection (T), and a working connection arrangement (L, R) with two working connections (L, R), and a steering motor, which is connected with the working connection arrangement (L, R). It is endeavoured to increase the possibilities of steering. For this purpose, it is ensured that an auxiliary force operated steering valve is arranged in parallel to the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R).

Abstract: The invention concerns a driving device, particularly a lifting device for a working vehicle, with a drive in the form of a hydraulic motor, the drive having a first connection and a second connection, a pump and a control valve arrangement between the drive and the pump. It is endeavoured to provide a simple way of extending the functionality of such lifting devices. For this purpose, the control valve arrangement can be switched from a first operating state, in which the motor is driven in a single-acting manner, to a second operating state, in which the motor is driven in a double-acting manner.