Komatsu Corporation

Yasuhiro Sato

Shuuji Hori

Masayoshi Mototani

Naoki Ishizaki

Nobumi Yoshida

Daisuke Kozuka

Koichi Miyake

Ryoji Wakisaka

A rotor and a seat mounted on a first shell is disposed between an annular first shell and an annular second shell both constituting a damper case, thereby forming a rotary damper device. A damper lever on which the rotor is mounted is hooked on a fixing pin fixed to a body. Viscous fluid such as highly viscous oil is charged into a damper chamber formed between the rotor and the seat, and a viscous resistance is applied to the rotor and the seat. In a state in which a rotation center of the rotary damper device is deviated from a rotation center of the shaft which is rotated by the operating lever, the damper case is fixed to a flange portion of the shaft, the rotor and the seat are allowed to rotate relatively to each other by an inclining operation of the operating lever, and a resistance force from the rotary damper device is applied to the operating lever.

Operating lever device

The aim is to improve operability in vehicles such as skid steer loaders and to reduce the burden on the operator. It is made easy to switch between a first operation pattern wherewith only one operation apparatus of two operation apparatuses is used in driving two actuators, and a second operation pattern wherewith the two actuators are driven using both of the two operation apparatuses. It is made possible to hold operation positions, and to release held positions, whether with an operation lever apparatus that is capable of operation in only one directional component or with an operation lever apparatus that is capable of operation in two directional components in the forward and backward direction and in the left and right direction. When a change to a first combination is designated by a pattern switching lever, the first combination (first operation pattern) is switched to by switching means. This effects correspondences between operation direction signals output from one operation apparatus of two (left and right) operation apparatuses and the drive directions of left and right running actuators. It is thereby made possible to drive left and right running bodies by operating one of the operation levers (the left operation lever). When a change to a second combination is designated by the pattern switching lever, the second pattern (second operation pattern) is switched to by the switching means. Thereby correspondences are effected between the operation direction signals output from the left operation apparatus and the drive directions of the left running actuator, and correspondences are effected between the operation direction signals output from the right operation apparatus and the drive directions of the right running actuator. It is thereby made possible to drive the left and right running bodies by operating both the left and the right operation lever. When a switching valve is switched to a valve position, and the operation lever has been operated so as to tilt, the operation lever is held in that tilted position. And when the switching valve is switched to another valve position, the operation lever holding condition is released.

Apparatus for altering operation apparatus and actuator combinations, and operation lever apparatus

A pressure compensating valve ( ) comprises a main valve ( ) that is operated in such a way as to increase the area of the opening between an inlet port ( ) and an outlet port ( ) by means of pressure acting on a first pressure receiving component ( ). The pressure compensating valve ( ) is also operated in such a way as to reduce the area of the opening by means of pressure acting on a second pressure receiving component ( ) and pressure acting on a third pressure receiving component ( ). The pressure compensating valve ( ) is designed to allow the pressure (Pa) of the pressurized oil flowing to the inlet port ( ) to act on the first pressure receiving component ( ) and the pressure (Pb) of the load driven by the pressurized oil flowing from the outlet port ( ) to act on the second pressure receiving component ( ). A control pressure producer ( B) is provided for allowing control pressure (Pe) resulting from a reduction in the pressure (Pa) of the inlet port ( ) to act on the third pressure receiving component ( ). An unloading pressure control valve and an variable bleed valve can also be provided. This structure allows the pressure compensated characteristics to be changed as desired. The unloading start pressure is also preset so as to improve response in terms of the hydraulic actuators. Energy loss can also be minimized, allowing the rapid start-up of the hydraulic actuators to be controlled, machines can be made smaller, and high precision control can be achieved.

Pressure compensating valve, unloading pressure control valve and hydraulically operated device

A vehicle advances forward while turning to the right when an operating lever is tilted forward and to the right, that is, being operated in a direction intermediate between the forward direction and right-hand direction. Only an output signal of the component corresponding to the forward direction is preserved when the operating lever is released. The component corresponding to the right-hand direction returns to the neutral position, and the signal output is brought to zero. The vehicle therefore moves only forward. The operating position can thus be preserved and a signal output state can be held for a single directional component selected from longitudinal and transverse direction components when operating the operating lever device which is tilted along the directional components in both longitudinal and transverse directions.

Growing community of inventors

Oyama, Japan

Yasuhiro Sato