Abstract: A hydraulic system for the components of a street sweeper or the like is disclosed which includes a hydraulic pump and tank connected in series with the motor of an elevator, the motor of a pick-up broom, the motor of a right gutter broom, and the motor of a left gutter broom with each broom motor being driven in response to closing a by-pass valve. The system also includes a control circuit for raising and lowering the several vertically movable components and hydraulics locking them in selected positions. The hydraulic system further includes a hydrostatic drive system including a two-speed shift control assembly.

Abstract: A hydrostatically operated vehicle, such as a street sweeper, includes an engine driven reversible hydrostatic pump coupled to a single hydrostatic pump driving wheels of the vehicle. The pump is shiftable from neutral to reverse and forward, low and high speed positions, and the hydrostatic motor is controlled between low and high speed positions with a metering valve automatically adjusting the motor speed in response to variation in reaction torque between the drive wheels and the ground. The vehicle also includes a reversible hydrostatic component drive system for powering motors which drive an elevator, pick-up broom and two gutter brooms in a forward working direction and which may be reversed for clearing debris jams by reversing the pump. The component drive system includes valve means for selectively driving the gutter brooms and for holding the gutter brooms inactive when the pump is driven in reverse.

Abstract: A hydrostatic propulsion system and method of operation is disclosed for smoothly driving a vehicle, such as a street sweeper. The system includes a shift lever for selectively moving a pump stroking valve into reverse, neutral, low forward, and fast forward speed positions to prepare the system. After the shift lever has been placed in a forward or reverse position, an accelerator pedal must be depressed to partially or fully close an inching throttle valve before the pump swash plate moves from its zero piston displacement position and begins to pump fluid to the hydrostatic motors. Hydrostatic braking forces are applied when the accelerator pedal is released and also in response to initial depression of a brake pedal for providing normal braking to the vehicle. Further depression of the brake pedal operates a conventional brake system for panic stops.