Kabushiki Kaisha Komatsu Seisakusho

Masaru Nakamura

Takashi Kuse

Shingo Ota

Teruo Nakahara

A hydraulic vehicular transmission has a plurality of drive speed establishing devices (e.g. clutches) to be actuated for selecting a drive speed, and a pair of similar drive direction establishing devices to be actuated for selecting a drive direction. The drive establishing devices are all actuated and deactuated hydraulically by respective solenoid operated control valves via respective pilot operated valves. Since the solenoid valves are susceptible to malfunctioning, as in the event of trouble in the associated electrical circuitry, emergency control valves are interposed respectively between the solenoid valves and the pilot operated valves. Each emergency control valve is to be hand operated in the event of the malfunctioning of the associated solenoid valve for actuating or deactuating the associated speed or direction establishing device via the associated pilot operated valve. Additional features are incorporated for the greater utility of the transmission control system.

Fluid operated transmission control system

A vehicle inching mechanism is interlocked with a braking mechanism so as to overlap their operating ranges without hampering the low-speed start or stop of the vehicle by the inching mechanism. An inching pedal and a brake pedal are mounted side by side on a stationary shaft via sleeves rotatably fitted thereover and linked to an inching valve and a brake master cylinder, respectively. The sleeves have square jaws at their opposed ends for mating engagement, with clearances therebetween to allow rotation of either sleeve relative to the other within limits. A torsion spring is anchored at one end to the inching pedal sleeve and held at the other end against an abutment on the brake pedal sleeve. Upon depression of the inching pedal, therefore, not only the inching valve but also the brake master cylinder is activated, first through the torsion spring and then through the intermeshing jaws. The depression of the brake pedal results only in the actuation of the master cylinder.

Growing community of inventors

Matsutou, Japan

Masaru Nakamura