Kabushiki Kaisha Komatsu Seisakusho

Hiroyuki Taki

Hidenori Mizuguchi

Hiroshi Ota

Masanovu Ogura

Toru Tanabe

A system suitable for positively holding an earthmover in a fixed position during excavating or loading operation, comprising a first air reservoir in communication with a parking brake via a parking control valve. A second air reservoir communicates with front and rear wheel brake cylinders via a dual brake control valve assembly and pneumatic-to-hydraulic converters. A pilot-operated source selector valve coacts with shuttle valves to normally allow communication between the brake control valve assembly and the converters and, upon application of the parking brake by the parking control valve, to place the first air reservoir in communication with the converters. Thus the actuation of the parking control valve results in the application of not only the parking brake but also the service brakes. Interposed between the converters and the brake cylinders, pilot-operated brake locking valves also respond to the actuation of the parking control valve for holding the service brakes applied by permitting fluid flow only in a direction from the converters to the brake cylinders.

Combined parking and service brake system

A fluid control circuit for a radio controlled vehicle for operating an engine, transmission, steering, movable elements of earth-moving machines and braking device of the vehicle by means of radio control. The control circuit has plural shuttle valves interposed between brake cylinders and solenoid operated valves for controlling the brake cylinders. A circuit changing valve is interposed between a conduit communicating with the source of fluid under pressure and conduits communicating with operating cylinders for the engine, transmission, steering, earth-moving machines and braking devices through respective solenoid valves and the shuttle valves. Circuit changing valve is manually operable for selectively feeding fluid in pressure from the source thereof to either conduit communicating with the respective operating cylinders. Thus, the remote control of the vehicle can be simply changed to a manual one or vice versa by a single operation.

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Komatsu, Japan

Hiroyuki Taki