Abstract: Cushioned swing circuits sometimes have a restricted passage between the motor conduits to allow the implement controlled by the swing circuit to coast to a stop. However, opening and closing of the restricted passage was manually controlled, thereby requiring an additional manipulative step by the operator. The present cushioned swing circuit includes a cushion valve moveable to an open position to establish communication through vent line means when a pressure differential greater than a predetermined level is generated in one of the motor conduits connecting a directional control valve to a hydraulic motor. The cushion valve is retained in the open position for a predetermined limited time after the pressure differential drops below the predetermined level so that the inertia generated pressure in the circuit is dissipated through the vent line means.

Abstract: Service personnel may confuse one dip stick for another in vehicles having a number of fluid reservoirs. When the reservoirs have air entrapped within them during filling, hydraulic lock can occur. Herein, a filler tube structure (20) and a dip stick tube structure (30) have their top ends held within a tubular fitting (40) which is covered by a single cap (58). This eliminates any possible confusion as to the dip stick tube structure (30) which corresponds to a particular reservoir or chamber (12). In the preferred embodiment venting of the chamber (12) to which the fluid is being added is provided via an interior passage (32) of the dip stick tube structure (30), thus preventing hydraulic lock.

Abstract: A drive train includes a hydrostatic transmission unit and a multiple speed range transmission unit arranged in series between a prime mover and a primary output shaft, variable displacement and torque transmitting capacity of the hydrostatic transmission unit being adjusted by hydraulic controls including a speed control valve for developing a differential pressure signal proportional to a desired rate of operation, a modulating valve for regulating the differential pressure signal corresponding to accelerating and decelerating operation of the transmission, a directional control valve for determining the direction of operation of the hydrostatic transmission unit, and a range selector valve for shifting the operating speed range of the multiple speed range transmission as the hydrostatic transmission approaches a limit of displacement, the displacement of the hydrostatic transmission being automatically reset in response to shifting of the multiple speed range transmission.

Abstract: A drive train includes a hydrostatic transmission unit and a multiple speed range transmission unit arranged in series between a prime mover and a primary output shaft, variable displacement and torque transmitting capacity of the hydrostatic transmission unit being adjusted by hydraulic controls including a speed control valve for developing a differential pressure signal proportional to a desired rate of operation, a modulating valve for regulating the differential pressure signal corresponding to accelerating and decelerating operation of the transmission, a directional control valve for determining the direction of operation of the hydrostatic transmission unit, and a range selector valve for shifting the operating speed range of the multiple speed range transmission as the hydrostatic transmission approaches a limit of displacement, the displacement of the hydrostatic transmission being automatically reset in response to shifting of the multiple speed range transmission.

Abstract: A drive train includes a hydrostatic transmission unit and a multiple speed range transmission unit arranged in series between a prime mover and a primary output shaft, variable displacement and torque transmitting capacity of the hydrostatic transmission unit being adjusted by hydraulic controls including a speed control valve for developing a differential pressure signal proportional to a desired rate of operation, a modulating valve for regulating the differential pressure signal corresponding to accelerating and decelerating operation of the transmission, a directional control valve for determining the direction of operation of the hydrostatic transmission unit, and a range selector valve for shifting the operating speed range of the multiple speed range transmission as the hydrostatic transmission approaches a limit of displacement, the displacement of the hydrostatic transmission being automatically reset in response to shifting of the multiple speed range transmission.

Abstract: A hydrostatic transmission has a pair of variable displacement overcenter hydraulic pumps and first and second rotary servo valves. Each servo valve has a housing connected to the respective pump and a valve spool rotatably positioned within the housing for controlling the output displacement of the respective pump. A mounting plate extends between and is releasably connected to the housings of the first and second servo valves. A first device is connected to the valve spool of the first servo valve for selectively rotating said first servo valve spool, said first device being mounted on said mounting plate adjacent said first servo valve spool. A second device is connected to the valve spool of the second servo valve for selectively rotating the second servo valve spool, said second device being mounted on said mounting plate adjacent said second servo valve spool.