Caterpillar Tractor Co.

Gordon W Johnson

James D Rinaldo

Maurice F Franz

Thomas J Bubula

Karl A Nerstad

Donald L Hopkins

Curtis E Chadwick, Iii

A fluid pressure operated clutch which transmits torque from an engine output shaft to a transmission input shaft, including a rotatable flywheel connected to the output shaft, an adapter connected to the flywheel for rotation with the flywheel, the adapter having a first annular plate with a fluid passage near the inner periphery of the plate, and a centrifugal piston which defines with the adapter a fluid chamber supporting a rotatable torus of hydraulic fluid. The piston has a second annular plate, slideable with respect to the first plate, and a second fluid passage near the outer periphery of the second plate. The first and second plates, at their inner peripheries, provide a controlled clearance to vary the rate of hydraulic fluid into the first fluid chamber as the second plate slides. A centrifugal relief valve is connected to the piston and has a conical valve member removably seated on an outlet of the valve to drain fluid from the chamber through the second passage and the outlet when engine overspeed occurs. A clutch pack of friction plates responds to movement of the piston to engage and disengage the clutch.

Centrifugal clutch with an overspeed relief valve and clutch modulation

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. Operating speed limits are automatically established for the drive train by an override speed control valve which manually adjusts the differential pressure signal for reduced torque transmission through the drive train when the prime mover is operating below a minimum speed. A speed limiting control valve responds to operation of the prime mover above a maximum selected speed for automatically applying a brake within the drive train in order to supplement dynamic braking capacity of the transmission unit, the speed limiting control valve including means producing a feedback signal for resisting manual operation of the override speed control valve in proportion to engagement of the brake within the drive train.

Controls for combined hydrostatic and multiple speed range transmission

A vehicle includes a variable displacement fluid pump and a variable displacement hydrostatic motor for driving the tracks of the vehicle. An auxiliary reversible motor may be actuated in one and the other directions to provide steering of the vehicle through planetary drives associated with the tracks of the vehicle.

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Peoria, IL, United States of America

Gordon W Johnson