Rear drive inching control for a four wheel drive vehicle

Patent · Mon Mar 23 23:00:00 EST 1987

OSTI ID:6618644

Headrick, C R

This patent describes a vehicle having mechanically actuated front drive means including a main drive transmission, hydraulically actuated rear drive means, brake means, hydraulically actuated apparatus for performing work functions, a source of hydraulic fluid, and conduit means for delivering hydraulic fluid. It also has an inching system for moving the vehicle at reduced speeds while maintaining sufficient hydraulic fluid flow and pressure for actuating the apparatus. The inching system comprises: means for controlling the fluid pressure to the rear drive means; means for restricting the flow of hydraulic fluid from the source to the controlling means to a level below that of the flow to the apparatus; means for metering hydraulic fluid from the controlling means so that fluid pressure available to the rear drive means is progressively reduced; means for selectively actuating the fluid metering means. The actuating means is movable from a first position in which the front and rear drive means are operative to a second position in which the main drive transmission is placed in neutral to disconnect the front drive means so that the rear drive means alone is operative. The actuating means then is movable through a third position in which the fluid metering means is actuated to drain fluid from the controlling means at a progressively increasing rate. The actuating means then is movable to a fourth position in which the rear drive means is inoperative and the brake means are actuated.

• Assignee: Gradall Co., New Philadelphia, OH
• Patent Number(s): US 4651846
• OSTI ID: 6618644
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330602* -- Vehicle Design Factors-- Engine-Transmission Matching
BRAKES
CONTROL
CONTROL EQUIPMENT
EQUIPMENT
FLOW REGULATORS
FLOWMETERS
FLUIDS
HYDRAULIC CONTROL DEVICES
HYDRAULIC FLUIDS
MACHINE PARTS
MEASURING INSTRUMENTS
MECHANICAL TRANSMISSIONS
METERS
PRESSURE CONTROL
SPEED REGULATORS
VALVES
VEHICLES
VELOCITY
WORKING FLUIDS