Abstract: In a hydrostatic transmission or integrated hydrostatic transaxle having a housing forming an oil sump and a hydraulic pump and hydraulic motor mounted in the sump and connected through hydraulic porting, a filter housing or other structure defining an internal volume is mounted adjacent to the check valves for the hydraulic porting. Oil passing into this internal volume is filtered to prevent the introduction of contaminants into the hydraulic porting. A himney is formed as part of the filter housing and extends upwards therefrom, and is open to the internal volume. The chimney also includes an opening to permit air to escape to the oil sump, to reduce the risk of air being introduced into the hydraulic porting through the check valves.

Abstract: A hydraulic fluid reservoir for a hydraulic power system includes a reservoir housing having an internal chamber for containing a supply of hydraulic fluid, an outlet for communicating the fluid from the housing to an inlet of a hydraulic pump, and a return flow inlet for receiving a return flow of fluid into the chamber. The reservoir includes a flow diffuser having a diffuser inlet communicating with the return flow inlet for receiving at least a fraction of the return flow into the diffuser. The diffuser has an inner fluid guide wall that is preferably conical which diverges in the downstream direction in order to quiet any turbulence in the flow within the diffuser and to discharge into the bulk of the fluid into the chamber to be deaerated.

Abstract: A hydraulic pressure generating apparatus includes a hydraulic oil feed line for feeding hydraulic oil with high pressure from an oil tank to a hydraulic pressure control system of a generator by an oil feeding pump unit, a hydraulic oil return line for returning drain oil from the hydraulic pressure control system to the oil tank, and a circulation line for circulating and purifying the hydraulic oil of the oil tank by a circulating pump unit. In such apparatus, the hydraulic oil is flame resistant hydraulic oil which is hardly deteriorated by direct heating, and the flame resistant hydraulic oil is heated by a heater disposed in the oil tank.

Abstract: A hydraulic system includes an air sucking hydraulic circuit 8, an air sucking control valve 5, and a check valve 6 provided in or before and after the air sucking hydraulic circuit 8, hereby allowing a hydraulic fluid from the air sucking control valve 5 to flow to the hydraulic actuator 4 and preventing a flow of a hydraulic fluid from the hydraulic actuator 4 to the air sucking control valve 5.

Abstract: A strut exercise assembly for an aircraft comprises a fluid strut telescopic along a path. A couple selectively connects the fluid strut to a driver. The driver telescopes the fluid strut along a path through the couple.

Abstract: An oil pressure control apparatus for an internal combustion engine that has a source of hydraulic pressure and a hydraulic actuator which is actuated by hydraulic pressure provided via a fluid passage which is in communication with the source of hydraulic pressure. A control valve is disposed in the fluid passage for controlling the hydraulic pressure introduced to the actuator. A damper, which is disposed in a fluid communication between the hydraulic actuator and the control valve, is operative to attenuate the force of a pulsing stream of a working fluid in the fluid passage.

Abstract: The present invention involves a purge device for a steering gear assembly of a vehicle. The steering gear assembly includes a steering piston chamber having a piston moveably housed therein and having a hydraulic assist port formed on the steering piston chamber. The device comprises a purge channel in fluid communication with the hydraulic assist port and housed in the steering piston chamber. The purge channel extends to a channel opening positioned at a first portion in the chamber to purge trapped air from the chamber during operation of the steering gear assembly.

Abstract: A pump (10) includes a chamber (14) communicating with a fluid inlet (12) and a fluid outlet (13) above the centerline thereof to minimize dead air space where air bubbles might form. A connector (21) having a bend or elbow (26) is formed at the fluid inlet (12). Upon actuation of a solenoid (37), a plunger (39) carrying a diaphragm (42) is moved to draw fluid around the elbow (26), through a valve (19) positioned at the fluid inlet (12), through the chamber (14), and out of the pump (10) through a valve (30) positioned at the fluid outlet (13). The energy of the fluid which might otherwise create a water hammer effect is absorbed by the elbow (26) prior to reaching the pump (10).

Abstract: The present invention meets these objectives providing an IDG hydraulic system that utilizes in flow series arrangement a scavenge pump, a spool valve and a boost pump. When spool valve detects an interruption in the supply pressure to the boost pump due to an adverse “g” condition, it reconfigures the system to a closed loop system. In this mode, the oil returning from the CVT is re-circulated back to the boost pump instead of back to the scavenge pump. Oil lost to leakage is replenished by an oil accumulator that use the gas pressure in the IDG's casing to expel fluid from the accumulator into the recirculating flow.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: A subsea hydraulic control module that is totally enclosed such that the hydraulic fluid does not contact the seawater. The majority of the power for the module comes from the hydrostatic pressure of the sea itself. Two oil-over-seawater actuators each have an internal piston that separates the oil from the seawater. Each actuator is provided with two solenoid valves that control the flow of seawater. A fluid line and one solenoid valve on the seawater side of each actuator is in fluid communication with a seawater recovery reservoir. These two valves are also in fluid communication with each other through a common fluid line to the seawater reservoir. The remaining solenoid valve on the seawater side of each actuator may be selectively opened or closed to the ambient seawater. A hydraulic line on the oil side of each actuator is in fluid communication with the equipment to be controlled.

Abstract: A single-fluid, multiple-reservoir hydraulic system and a method and system for fluid distribution are provided. The single-fluid, multiple-reservoir hydraulic system utilizes a single-fluid to supply all vehicle power and lubrication fluid requirements. The hydraulic system combines separate fluid reservoirs and fluids into a single integrated system that services multiple systems without a need for multiple dedicated reservoirs. The hydraulic system maintains and prioritizes separate dedicated fluid reserves within one reservoir and may also reach and maintain consistent fluid temperature and viscosity. Consistent performance and extended component life are provided while maintaining circulation with the hydraulic system. In addition, the single fluid and single reservoir hydraulic system have a single fluid fill point, a common reservoir check point and fluid level monitor.

Abstract: An axle driving apparatus, wherein at the interior of a housing is formed an internal fluid sump, and are disposed a fluid circuit, which fluidly connects a hydraulic pump with a hydraulic motor so as to constitute a hydrostatic stepless transmission, and a fluid feeding port, which is opened toward the fluid circuit when the fluid pressure within the fluid circuit becomes negative; at the exterior of the housing is formed an external fluid sump, which is provided with a fluid inlet port, a fluid outlet port and a filter element interposed between the both of ports; a fluid extracting means communicates the internal fluid sump with the fluid inlet port, and a fluid introducing means communicates the fluid outlet port with the fluid feeding port.

Abstract: An arrangement for removing contaminants from a hydraulic system includes a portable fluid pump for introducing fluid into or evacuating fluid from the hydraulic system and a resilient adapter capable of conforming to openings of different size in the hydraulic system and provide a sealed fluid connection between the pump and the hydraulic system. Contaminants are removed by applying the resilient adapter to an opening in the hydraulic system to provide a sealed fluid connection and by either introducing fluid into the hydraulic system or evacuating fluid from the hydraulic system, as appropriate to effect the removal of contaminants from the system.

Abstract: The invention relates to a piston pump for a slip-controlled hydraulic vehicle brake system. The piston pump has a piston which is driven to execute a stroke motion, and two check valves as an inlet valve and outlet valve for controlling the fluid flow through the piston pump. The outlet valve has a valve closing spring that effects a fast closure of the outlet valve. To enable completely evacuating a positive displacement chamber of the piston pump, the invention includes connecting an evacuation valve, embodied as a springless check valve with a small diameter and with a lightweight valve closing body, hydraulically parallel to the outlet valve.

Abstract: A hydraulic actuator and a method for degassing hydraulic actuators having t least two chambers are disclosed. For actuating a hydraulic element, for example a piston in a piston-and-cylinder unit the hydraulic actuator may be supplied with pressurized hydraulic fluid from a hydraulic source via gate valves. The chambers may be interconnected via another gate valve such that when the other gate valve is open, a closed flushing circuit may be configured, starting from a hydraulic fluid container via a hydraulic pump, a first gate valve, a first chamber, the additional valve, a second chamber, a second gate valve and back to the hydraulic fluid container.

Abstract: The present invention provides an air compressor which includes an air drier filled with a drying agent and having a first passage for supplying compressed air to one air supplied part while absorbing moisture from the compressed air by passing the compressed air through the drying agent (27) and a second passage (28a) for supplying the compressed air to another air supplied part without passing the compressed air through the drying agent. The air supplied through the first passage returns through the same passage to dry the drying agent.

Abstract: A remotely located brake booster for supplying an input force to a pressurizing device to develop pressurized fluid to effect a brake application. The brake booster responds to an actuation signal in the form of pressurized fluid being communicated from a control apparatus activated by an operator. The brake booster has a housing with a bore and a piston located therein to define an operational chamber. The housing has an inlet port through which pressurized fluid from the control apparatus is receiving by the operational chamber. The piston moves from a rest position to an actuation position in response to pressurized fluid being received in the operational chamber to produce the input force for operating the pressurizing device.

Abstract: A spring brake actuator (10), with a large-force compression spring (72) in a spring chamber (101) of the housing, has vent openings (102) in the housing communicating with the spring chamber (101). A gas permeable filter element (104) covers the vent openings (102), and a filter frame assembly (106) is disposed over the filter element. The filter frame assembly (106) defines tortuous air passages from the filter element (104) to atmosphere so that air entering the spring chamber from atmosphere will be substantially free of contaminants.

Abstract: A variable flow hydraulic system including a fixed displacement pump and a variable displacement pump for supplying pressurized hydraulic fluid in a machine is disclosed herein. Along with the dual pumps, the system includes a reservoir, a flow sensitive unloading valve, and a conduit system for distributing fluid flow between the system components. The reservoir stores fluid for use in a work circuit with an actuator for performing work in response to applied fluid flow. The fixed and variable displacement pumps are driven by a power source (e.g., an engine) to provide a fixed and a variable fluid flow, respectively. The variable flow is applied to the work circuit. As for the fixed flow, the unloading valve switches the fixed flow to either bypass or be applied to the work circuit in response to a flow signal, which depends upon the fluid flow being applied to the work circuit.

Abstract: A brake apply system includes a power booster in which, when released and at-rest, a leg of a stop engages a clip and an extension of a valve body engages the clip so that an annular rib of the valve body is axially spaced away from the stop by a distance G. At the same time, a first valve seat is engaged with a first annular valve element closing a pressure supply conduit off from a variable pressure chamber and a second valve seat is spaced away from a second annular valve element by a distance T, opening the variable pressure chamber to an atmospheric pressure chamber. When the power booster is applied, the second valve seat moves the distance T and engages the second annular valve element closing the variable pressure chamber off from the atmospheric pressure chamber and the first valve seat separates from the first annular valve element opening the pressure supply conduit to the variable pressure chamber.

Abstract: A boom and drive train hydraulic system is described having a pressure source, preferably a pump operated by a motor, said pressure source providing hydraulic fluid at a high pressure to a first set of valves used to operate the drive train of the system. The first set of valves is equipped with a power beyond for allowing the hydraulic fluid to flow from the first set of valves to a second set of valves. At the second set of valves a pressure control is provided to reduce the pressure to a desired lower pressure. The second set of valves provides the hydraulic fluid at this reduced pressure to the boom portion of the system. The differential of the pressures is approximately 5,000 psi for the track system and approximately 2,500 psi for the boom system.

Abstract: A hydraulic system for a motor vehicle having a first flow circuit for steering power assist and a second flow circuit for a radiator cooling fan. The first flow circuit includes a reservoir, a power steering pump connected to the reservoir through a first inlet conduit and a first return conduit, a steering assist fluid motor, and a first flow control valve. The second flow circuit includes the aforesaid reservoir, a second pump connected to the reservoir through a second inlet conduit and a second return conduit, a second fluid motor for the radiator cooling fan in the second return conduit, and a second flow control valve. Fluid in the first return conduit is conducted into the reservoir substantially without turbulence. Fluid in the second return conduit is conducted into the reservoir as a jet stream aimed at a submerged passage in a venturi tube. The submerged passage communicates with a feeder conduit between the reservoir and each of the first and the second inlet conduits.

Abstract: A hydrostatic transmission with a closed hydraulic circuit includes a consumer which is connected through work lines to a reversible hydraulic pump and is pressurized on both sides by an external pressure source. The hydraulic circuit includes a first continuous rinsing and feeding circuit which depends on the leakage flow of the hydraulic pump and possibly a second discontinuous rinsing circuit separate from the first circuit and connected to the external pressure source. The hydrostatic transmission further includes an adjustable regulating device which determines through a valve the adjustment of the hydraulic pump. The regulating device, which may be arranged outside of the immediate vicinity of the hydrostatic transmission, interacts with a control device which is directly assigned to the hydrostatic transmission and includes a valve constructed as a servo valve, wherein, for adjusting the arrangement, the servo valve can be switched to manual control.

Abstract: An arrangement for bleeding or flushing a hydraulic system includes a portable pump and a hydraulic fluid packet. The hydraulic fluid packet comprises a flexible receptacle which contains a body of hydraulic fluid. A spout is located at one end of the receptacle and an opening is provided at the opposite end of the receptacle. The spout can be connected to the pump and the opening allows the receptacle to be suspended with the spout facing down. As hydraulic fluid is withdrawn from the receptacle, the receptacle collapses around the remaining hydraulic fluid to inhibit the formation of air pockets in the receptacle.

Abstract: An arrangement for bleeding a hydraulic system includes a portable pump and a portable container for hydraulic fluid. The container is provided with a pair of quick-disconnect coupling elements. The pump has an inlet and an outlet, and an inlet hose is provided for connection to the pump inlet while an outlet hose is provided for connection to the pump outlet. Both hoses have quick-disconnect coupling elements which are complementary to the coupling elements of the container so that the pump can be primed from the container. The arrangement further includes a third hose which is provided with an additional quick-disconnect coupling element as well as a fitting connectible to a hydraulic system. The additional quick-disconnect coupling element is complementary to the coupling elements of the inlet and outlet hoses thereby allowing the pump to apply either pressure or suction to a hydraulic system. An adapter which can replace the outlet hose permits adaptation of the pump to openings of different size.

Abstract: A purification apparatus for removing gases and water from a fluid in a system, including a tank which has an expansion chamber for fluid in the system. A pump pumps the fluid in a circulation circuit of which the purification apparatus is an integral part. A closed chamber has a fluid-free upper part and contains a level-sensing device which controls flow of fluid to the closed chamber. The fluid-free upper part of the closed chamber is connected with a vacuum pump which sucks gases from the closed chamber and creates a lower pressure in the closed chamber than at an outlet of the apparatus. A pressure-generating device sucks fluid from the closed chamber.

Abstract: This invention provides for reliable, long-life operation of fluid pressure responsive engines directly from raw natural gas at the wellhead by introducing a novel rotary dynamic contaminant filter system especially adapted for removing liquid and abrasive particle contaminants from the flow of natural gas under high pressure from the wellhead. Thus, a novel turbine type gas driven rotor in the gas flow stream has rotor blades slanted at an angle to the rotation axis to serve as a ramp for removal of contaminants as the flow of gas spirals upwardly from input to output ports. This dynamic filter employs the combined forces of gravity, centrifugal force and those imposed by interception with a contaminant flow ramp to encounter and remove a wide range of microscopic contaminants from the high pressure wellhead natural gas.

Abstract: A hydraulic system including a re-circulation flow loop including a hydraulic pump and an actuator in fluid communication via a high pressure feed line and a low pressure return line, the system further including an air separator in fluid communication with the low pressure line for removing air from hydraulic fluid flowing along said re-circulation loop.

Abstract: A vehicle height control system for controlling vehicle suspension includes an air suspension unit and a compressor for producing compressed air to be supplied to the air suspension unit. An air drying chamber is provided between the compressor and the air suspension unit for drying the compressed air supplied from the compressor to the air suspension unit. An air drying filter is positioned in the air drying chamber for removing water and moisture from the compressed air produced by the compressor and to be supplied to the pneumatic actuator, the air drying filter being a non-woven cloth made of fibers including fibers having water and moisture absorbing performance.

Abstract: Motor vehicle hydrostatic transmission having an internal oil expansion chamber including a main housing having at least one opening, this main housing including a sump pump oil reservoir having a predetermined volume of sump pump oil and an input cover sealingly attached to an opening in the main housing, this input cover having an internal oil expansion reservoir which captures or traps a specified volume of air above the sump pump oil level. Thus, when the oil level rises due to elevated operating temperatures, this captured or trapped air volume is decreased resulting in an increase in both the captured or trapped air pressure and the sump pump oil pressure. This causes an increase in the hydrostatic transmission's operating efficiency since the sump pump oil pressure acts as a charge pump to supercharge the low pressure inlet of the closed loop hydraulic system. In addition, the hydrostatic transmission bearing performance will increase since they are designed to operate under pressure.

Abstract: An axle drive unit for facilitating maintenance, such as replacement or cleaning of an oil filter for filtering operating oil. The present invention uses the interior of the housing of the axle drive unit as an oil sump. The axle drive unit has a hydrostatic transmission for driving axles and operating oil supply means for supplying the operating oil to the transmission. A plug-in bore is open at the side wall of the housing opposite to a suction port of the operating oil supply means. The oil filter is inserted into the housing through the plug-in bore and connected to the suction port. The plug-in bore is covered with a cover member for freely opening and shutting the bore. Such construction enables a worker, when inspecting or replacing the oil filter, to remove the cover member from the side wall of the housing while the axle drive unit is being loaded on a vehicle. The oil filter can simply be inserted or removed through the open plug-in bore.

Abstract: A hydraulic system has a master cylinder, one or more servo cylinders and a line connecting each servo cylinder to the master cylinder. Air is removed from a line by pumping hydraulic fluid into the respective servo cylinder using a reciprocating hand pump. The pump has a transparent pumping chamber which automatically refills with fluid after each pumping stroke, and the pumping chamber has graduations which indicate the amount of fluid in the pumping chamber. A measured amount of fluid equal to the volume of a line is pumped into the associated servo cylinder. If two servo cylinders are fed by respective branch lines of a common supply line, the amount of fluid pumped into the first servo cylinder equals the volume of the corresponding branch line while the amount of fluid pumped into the second servo cylinder equals the volume of the corresponding branch line plus the volume of the supply line.

Abstract: A hydraulic control apparatus for a hydraulically operated vehicular transmission has control valves corresponding to hydraulic engaging elements provided in the transmission. The supply and discharge of hydraulic oil to and from the corresponding hydraulic engaging elements are controlled by the control valves. The hydraulic control apparatus has an oil supply passage which is connected to a hydraulic oil source and into which a throttle is interposed. The oil supply passage is connected to oil passages which are on a downstream side of each of the control valves and which are to be communicated with the hydraulic engaging elements. Check valves are interposed in the oil supply passage to allow for the hydraulic oil flow only from the oil supply passage to the oil passages on the downstream side of each of the control valves.

Abstract: A connector assembly (76) connects a power steering fluid reservoir (18) on a vehicle (10) with a bulk holding tank (44) for power steering fluid (46). Upon initiation of the operation of a vehicle engine (16), a control valve (56) is opened to enable power steering fluid (46) to flow from the bulk holding tank (44) through the connector assembly (76) into the reservoir. Operation of a power steering pump (14) on the vehicle (10) causes power steering fluid to flow from the reservoir (18) through the power steering pump (14) and reservoir (18) to the bulk holding tank through return conduits (22, 110, and 78). Air is entrained in the flow of fluid in the return conduits (22, 110 and 78). A vacuum pump (86) is advantageously connected with the bulk holding tank (44) to promote removal of air from the power steering fluid (46) returned to the bulk holding tank.

Abstract: The disclosure relates to a new valve and a hydraulic system incorporating such valve. A mode-selection assembly on the valve is adjustable between an open-loop position for system purging and a closed-loop position for normal system operation. A sealing member moves with the spool and with the mode-selection assembly in the open-loop position, the sealing member may be urged against a stationary abutment member in the valve. Such cooperative sealing member/abutment member contact blocks the closed-loop flow path and causes fluid to be "rerouted" to tank rather than back to the pump. The system is thereby temporarily converted to open-loop configuration for purging and is restored to closed-loop configuration by moving the mode-selection assembly to the closed-loop position. The new valve is particularly useful in hydraulic steering circuits for boats.

Abstract: The invention is directed to a compressed air control apparatus for supplying compressed air to a pneumatic actuator, which includes a compressor having a head member with a pressure chamber defined therein for generating compressed air, an intake valve for introducing air into the pressure chamber, and a discharge valve for discharging the compressed air. A dryer is disposed in a dry housing to dry the compressed air discharged from the compressor. A supply solenoid valve is disposed in a supply valve housing to control the compressed air supplied to the pneumatic actuator. An exhaust solenoid valve is disposed in an exhaust valve housing to control the compressed air discharged from the pneumatic actuator. The head member, dry housing, supply valve housing and exhaust valve housing are integrally formed by synthetic resin to provide an integral housing.

Abstract: A regulator for controlling the air pressure of compressed air in an air reservoir which serves as a source of motive compressed air for an air driven device is provided. A method is provided for maintaining sufficient operating pressure of a pressurized air supply tank utilized in air driven systems such as a vehicle braking system.

Abstract: An over the highway truck having a power steering system including an improved hydraulic circuit for operation of the system is disclosed. The system includes a heat conductive metal frame element, a power steering pump, and conduits connecting an output of the pump to at least one steering assist actuator. The system also has a heat conductive, metal, hydraulic reservoir defining an internal power steering fluid chamber is connected to the frame element in heat transfer relationship. Supply and return conduits respectively connect the chamber to the pump and the actuator to provide a combination wherein the frame element and reservoir together function as a heat sink to cool power steering fluid. The reservoir has a housing having a base portion and an internally connected, upstanding, circumferentially endless side portion. The housing has flow directing passages adjacent its base portion and communicating with the chamber for delineating fluid flow across the base portion in heat transferring relationship.

Abstract: A device for purging marine hydraulic steering systems containing a hydraulic pump actuated by a boat steering-wheel and having first and second fluid inlet/outlet ports, a hydraulic piston cylinder device with first and second chambers on either side of the piston and first and second hydraulic conduits between the inlet/outlet ports of the pump and corresponding inlet/outlet ports to the respective chambers. A valve unit can be coupled into the respective connection between the inlet/outlet port of the respective chamber and the inlet/outlet port of the pump, via which valve unit air in the fluid can be released. The valve unit (8) has manually operated purging valves (33, 34), by which the respective chamber (12, 13) can be coupled to a third conduit (26) which opens into an inlet (5) of a fluid receptacle (1).

Abstract: Valve system for a vehicle gas suspension system having a central chamber (41) to which pressurized gas is admitted via valve 50 or from which pressurized gas is exhausted via valve 51. Interposed in gas communication paths between the central chamber and each gas suspension unit (46-49) is a respective on-off valve unit (42-45). The valve system includes a regenerative drier (56) and a cushion valve (70) for protecting a compressor from overload during start-up.

Abstract: In all hydraulic systems, it is important to remove all entrained air, dirt and other impurities from the system prior to normal operation. In the subject invention, a method of purging and/or preconditioning a hydraulic system is provided and includes the steps of connecting a shunt line between opposite ends of respective fluid actuators and operating the respective valve mechanisms to force fluid from the source of pressurized fluid through the respective valve mechanisms across the respective shunt lines and back to the reservoir. Likewise, the subject invention provides a method to purge the signal control system of any entrained air, dirt and other impurities. The method also provides an easy process of "warming up" the system or totally replacing all of the fluid in the system with another type of fluid, such as fluid for arctic conditions. The method of purging the signal control system includes selectively connecting a bypass line between the reservoir and the signal control system.

Abstract: An air conditioning system for a motor crane includes a heating circuit and a refrigerating circuit. The heating circuit comprises a hydraulic motor, a hydraulic pump, a radiator and a valve mechanism causing a pressure difference in the hydraulic oil flowing therethrough. The refrigerating circuit includes a compressor connected to the hydraulic motor and a condenser having a fan for forcing air thereover. The heating circuit is at least partially disposed in an air path in which the condenser is disposed. When the hydraulic oil bypasses the valve mechanism, a control device turns the fan on if the refrigerating circuit is not operating, and the temperature of the hydraulic oil sensed by the sensor reaches a predetermined temperature.

Abstract: A device for the improvement of the running conditions in a hydraulic installation or in a so-called hydraulic system. The device contains a central circulating circuit separated from the influence of the atmosphere. To the circulating circuit are connected an outlet and an inlet for the connection of the hydraulic fluid to the other part of the hydraulic system. The circulating circuit is divided into at least two chambers separated by respective pressure generating and pressure reducing units. The first chamber is to a certain extent an expansion room for the hydraulic fluid in the system which is separated from the atmosphere and it forms a low-pressure part in the circuit. The second chamber forms a high-pressure part which is directly connected to the outlet. The circulating circuit holds a medium for the cooling and filtering of the hydraulic fluid.

Abstract: A hydraulic power transmission including a compact external oil pressure takeoff apparatus which houses therein a hydrostatic transmission, and attaches thereto a charge pump. The transmission is capable of supplying operating oil and of taking out external oil pressure. Specifically, part of the discharge oil from the charge pump is adapted to be taken out from the housing so as to omit the need for an external takeout pump. An oil filter is disposed on the exterior of the housing, thereby facilitating maintenance of the hydraulic power transmission.

Abstract: A hydraulic brake system for a vehicle having a traction control system, in which at least one self-aspirating pump, pressure fluid can be aspirated through an intake line and a charging valve and can be fed into a brake line leading to at least one wheel brake. A pressure limiting valve that diverts pressure fluid from the brake line to the intake line is also provided. To speed up the braking intervention, the pump is briefly turned on and the charging valve is opened when the vehicle is started, to carry away any gas bubbles that might be located between the charging valve and the pump. This averts the possibility that the compression of gas bubbles that might be present at the onset of traction control could cause the pump to pump less pressure fluid. The method can be employed in hydraulic brake systems of motor vehicles with traction control systems.

Abstract: A method of charging a hydrostatic transmission with deaerated transmission oil wherein a hollow-bodied bellows attached to a housing plate for placement within the hydrostatic transmission housing, and a bleed plug for a bleed hole are removed, and the deaerated oil is caused to fill the transmission housing. Once the transmission has been completely charged such that the oil is at the bleed hole level, the hollow-bodied bellows attached to the housing plate is then secured to the hydrostatic transmission housing causing excess oil and air initially trapped within the hydrostatic transmission housing, to be purged through the bleed hole, while the transmission bleed hole plug is then secured into the transmission bleed hole.

Abstract: A hydraulic transmission system comprising a housing having at least an oil tank containing oil, an oil pump mounted in the housing and having an inlet port and an outlet port, an oil motor mounted in the housing and having an inlet port and an outlet port, a high-pressure oil passage defined in the housing and interconnecting the outlet port of the oil pump and the inlet port of the oil motor, a low-pressure oil passage defined in the housing and interconnecting the outlet port of the oil motor and the inlet port of the oil pump, an oil supply passage defined in the housing and interconnecting the low-pressure oil passage and the oil tank, for supplying oil pumped from the oil tank by the oil pump for circulation between the oil pump and the oil motor through the high-pressure oil passage and the low-pressure oil passage, and a return oil passage defined in the housing and connecting at least a portion of the low-pressure oil passage to the oil tank, for removing air trapped in the oil circulating between th

Abstract: An output pressure control apparatus particularly adapted for HVAC control applications, and being of the general type which admits a higher supply pressure to a controlled output line when it is desired to increase the pressure in the output line and which bleeds pressure from the controlled output line when it is desired to reduce the pneumatic output pressure. The pressure regulating apparatus requires only a single filter means and utilizes bidirectional flow of air through the filter means during normal operation which cleans the filter means.

Abstract: An apparatus and method are disclosed for the simple removal of liquid condensate, in particular of water of condensation, from compressed-air systems alternately subjected in operation to positive pressure and atmospheric pressure. The compressed-air system is first of all connected for a limited period, at intervals or after each subjection to positive pressure, to a vacuum generator in order to promote re-evaporation of the condensate and is evacuated by the latter before atmospheric pressure is passed in or let in again. In certain embodiments, a highly restricted reverse flow through the compressed-air system is permitted. The method is particularly suitable for use in small-volume compressed-air systems which do not have to be permanently subjected to positive pressure, e.g., in pneumatic door-closing aids for motor cars.