초록 ▼

A steering and ground speed control mechanism of a vehicle equipped with a dual-path hydrostatic drive system includes a pivot plate fixed to a vertical pivot post at a location between and equidistant from a pair of locations respectively linked to a pair of pump displacement control arms of a pair

A steering and ground speed control mechanism of a vehicle equipped with a dual-path hydrostatic drive system includes a pivot plate fixed to a vertical pivot post at a location between and equidistant from a pair of locations respectively linked to a pair of pump displacement control arms of a pair of pumps respectively coupled for delivering fluid to right- and left-hand drive motors coupled to right- and left-hand ground wheels. A train of elements for transferring steering inputs from a steering wheel to the pivot plate includes a timed belt and sprocket set with one of the sprockets being fixed to the pivot post and the other mounted to a fixed post together with a quadrant-shaped steering rack for pivotal movement about the fixed post in concert with the rack. Pivoting the pivot plate in opposite directions from a centered position causes different displacements of the pumps and, hence, in the two drive motors being driven at different speeds. A train of elements for transferring speed inputs from a speed control lever to shift the pivot plate back and forth in a nearly straight path includes a push-pull cable coupled between the lever and an arm having the pivot post pivotally mounted in one end thereof, with the arm being mounted for pivoting about the fixed post exclusive of the rack and sprocket. A spring-applied, hydraulically released latch is provided for latching the steering wheel and speed control lever in their respective “centered”and “neutral”positions when hydraulic pressure is absent and a “neutral”start switch is positioned for being activated for completing a vehicle starting circuit only when the steering wheel and speed control lever are in these positions.

대표청구항 ▼

In a vehicle steering and speed/direction control mechanism for a dual path hydrostatic transmission of a type including a pair of pumps respectively coupled for supplying pressure fluid to and receiving return fluid from a pair of hydraulic wheel drive motors respectively coupled to a pair of drive

In a vehicle steering and speed/direction control mechanism for a dual path hydrostatic transmission of a type including a pair of pumps respectively coupled for supplying pressure fluid to and receiving return fluid from a pair of hydraulic wheel drive motors respectively coupled to a pair of drive wheels and including control arms which are pivotable for effecting changes in the displacement of the pumps and direction of fluid flow to the pumps and, hence, changes in the speed/direction of the drive motors, a pair of links having first ends respectively coupled to the control arms of the pair of pumps and second ends coupled to a control plate at a pair of locations respectively spaced in opposite directions from a pivot axis defined by a vertical pivot post fixed to the control plate and mounted for rotation in a free end of a support arm mounted for swinging about a fixed post, a first train of motion transfer elements connected between a steering input member and the control plate for turning the latter in opposite directions from a centered position in response to moving the steering input member in opposite directions from a centered position, and a second train of motion transfer elements being connected between a speed/direction control input member and the support arm for pivoting the latter in opposite directions in response to movement of the speed/direction control input member in opposite directions from a neutral position, the improvement comprising: said first train of motion transfer elements including a toothed belt extending about first and second toothed sprockets of equal diameter; said first sprocket being mounted for rotation about said fixed post, exclusive of said support arm, and said second sprocket being fixed to said pivot post for pivoting in concert with said control plate; and said first train of motion transfer elements further including means for rotating said first sprocket in opposite directions in response to said steering input member being moved in opposite directions from its centered position.