Abstract: The disclosure relates to improvements in pumps and motors of the gear type. The gear elements are arranged within the pump or motor housing so that the ends or the tips of the teeth are spaced out of fluid sealing relationship and not pressed into the surrounding chamber wall on the low pressure side of the housing. Rigid sealing members of limited circumferential extent having a curved sealing surface and planar support and side wall surfaces are seated in a recess in the housing at the high pressure side of the gears for the purpose of providing a fluid seal between the tips of the teeth in a limited region adjacent the opening in the housing which is at higher pressure. The sealing members are positioned in a recess in the housing and are configured to be resistant to bending and movement. The sole support for the shoes is provided by planar surfaces on the side pressure plates.

Abstract: Hydraulic equipment useful as a pump or motor intended for applications where hydraulic fluid is exposed to contamination by abrasive particulate material is disclosed. Leakage paths from the high pressure chamber in a gear pump or motor are provided with inserts of an abrasion and erosion resistant material at points where wear from abrasives in the hydraulic fluid is aggravated. In particular, the bearing surfaces of the pressure loaded side plates are provided with an insert of abrasion and erosion resistant material in the mesh region of the teeth. Erosion and abrasion resistant rings are located on the side plates in the region surrounding the openings for the shafts and extending interiorly of the tooth root circle to the journal bearings.Also disclosed are radial sealing shoes which are supported by the side plates and are radially urged into sealing relationship with the tips of the teeth by the pressure existing at the high pressure side of the gears.

Abstract: The disclosure relates to improvements in pumps and motors of the gear type. The gear elements are arranged within the pump or motor housing so that the ends or the tips of the teeth are spaced out of fluid sealing relationship and not pressed into the surrounding chamber wall on the low pressure side of the housing. According to the disclosure, sealing members of limited circumferential extent are provided in the housing at the high pressure side of the gears for the purpose of providing a fluid seal between the tips of the teeth in a limited region adjacent the opening in the housing which is at higher pressure. The sealing members disclosed are a pair of separate shoes located adjacent the high pressure opening. The sole support for the shoes is provided by the side pressure plates.

Abstract: A drive system useful for driving reciprocating equipment such as saw mill log carriages or the like is disclosed. The drive system includes a plurality of fixed displacement pumps driven by a prime mover. The pumps in turn drive one or more fixed displacement hydraulic motors which drive the carriage. The pumps are provided with pressure responsive unloading valves which unload at different pressures so that as pressure on the system builds up one or more pumps are sequentially unloaded. An accumulator is charged at low pressures and provides fluid for driving the motors when required at the higher pressures. The inertial forces in the heavy carriage, during the time when the carriage is slowing down, are used to drive the fixed displacement motors as pumps. During this portion of the cycle, the motors are interconnected with the accumulator so that the pumping action of the motors is used to recharge the accumulator.

Abstract: A control system for plural circuits having motor-driven hydraulic pumps. As disclosed, a pair of pumps is connected in a hydraulic actuating circuit individual to that pair and the circuit includes an hydraulically operated actuator to be advanced and retracted by fluid under pressure delivered from the pair of pumps of that circuit. A single prime mover drives the pair of pumps and pumps in other circuits, and each circuit has a pressure-responsive control valve which provides for unloading a pump of the first circuit in response to increases in pressure in the various other circuits to a predetermined value at which, in the absence of such unloading, the input horsepower requirement has risen toward a value which would stall the prime mover.Pumps in several of the circuits may be sequentially and selectively unloaded.

Abstract: An emergency hydraulic system for a hydraulically powered device such as the power steering mechanism used on large earth-moving vehicles and the like is disclosed. The emergency system includes an auxiliary pump connected to the wheels or some other part of the vehicle so that the pump is operated despite engine failure whenever the vehicle is in motion. An inlet valve for the pump is held in the closed position whenever the vehicle prime mover is in operation so that the pump is deprived of operating fluid when an emergency condition does not exist. If the prime mover stops running so that the main hydraulic system is not operating and the power steering system is deprived of its source of power, the inlet to the emergency pump is opened so that the pump supplies operating fluid to the steering system so long as the vehicle is in motion. Since the pump is deprived of operating fluid when an emergency does not exist very little power is consumed.

Abstract: A control system for plural motor driven pumps is disclosed. The control system includes a control valve which provides for unloading one pump by diverting the flow of operating fluid from that pump back to reservoir whenever the flow through the valve or the load pressure exceeds a preselected level.

Abstract: The disclosure relates to plural, motor driven hydraulic pump circuits, including circuits having the pumps in at least one circuit operated in pairs with all pumps being driven by a single prime mover. A speed responsive control device unloads one pump in one circuit when engine speed drops below a predetermined value without regard to the source of the condition causing the slowdown. Also included is a crossover means for sensing the pressure in aother circuit for preventing reloading of the unloaded pump when speed rises above the predetermined value unless and until the pressure including the pressure sensed in the other circuit is below a predetermined pressure.

Abstract: An Emergency or back-up Hydraulic System for use with a primary hydraulic system in motor operated equipment is disclosed. The system illustrated is a steering system for a vehicle and includes a motor driven pump and a wheel driven pump for supplying hydraulic fluid to the steering system of the vehicle. The motor driven pump and the wheel driven pump are connected in series so that the fluid discharged from the motor driven pump is supplied to the inlet of the wheel driven pump. The inlet of the wheel driven pump also communicates with the reservoir as for example through the anticavitation check for the engine driven pump. By-pass connections are provided around the wheel driven pump so that fluid in excess of the demands of that pump are channelled to the steering circuit when the engine driven pump is in operation.

Abstract: The disclosure relates to a control system for hydraulic pumps driven by the engine of a vehicle or the like and used for operating an auxiliary mechanism such as a vehicle mounted implement, a power steering system or the like. The disclosed system includes means for interrupting the flow of operating fluid to the pump during periods of time when the output of the pump is not required. With the pump inlet closed, all of the hydraulic fluid on the suction side is immediately pumped out the pump discharge, leaving only a small amount of residual oil on the surface of the working parts to provide lubrication. A valve is provided to prevent fluid from returning to the pump because of downstream pressure in the circuit. Control means, utilizing pressure downstream from the pump, for operating the valve in the inlet of the pump are disclosed.