Hitachi Construction Machinery Co., Ltd.

Kenichi Miyata

Junichi Narisawa

Hiroshi Kusumi

Shuichi Ajiro

Satoshi Nozaki

Kenichiro Date

Yuhei Sato

Akio Kiue

A kelly-bar apparatus includes, for example, an inner kelly-bar, a second kelly-bar and an outer kelly-bar. These kelly-bars are relatively telescopically operable and torque is transmitted from outside to inside. When the second and outer kelly-bar are in a contracted position, they are supported by a spring on a spring support fixed to the inner kelly-bar. The bottom end of a torque transmitting projection of the inner kelly-bar is fitted into and welded to the spring support. The spring support is fixed onto an engagement member formed integrally with the inner kelly-bar. In addition, a stop member for preventing the second kelly-bar from coming away from the outer kelly-bar projects from the inner periphery of the outer kelly-bar at a location above the torque transmitting portion.

Cylindrical telescopic kelly-bar apparatus

In an industrial vehicle having at least first and second arms rotatably coupled to each other, a locus depicted by a tip of the second arm during rotation of the first and second arms is controlled. An amount of positional deviation of the tip of the second arm in the direction (compensating direction) perpendicular to the direction of the targeted locus (operating direction) is detected. A command value for the compensating velocity is determined from a command value for the operating velocity and the deviation. The driving of the first and second arms is controlled by the two velocity command values in the operating and compensating directions in such a manner that the tip of the second arm moves along the targeted locus. In short, positional feedback is provided by means of the positional deviation in the direction perpendicular to the targeted locus. In addition, the direction of the targeted locus is set as the direction of installation of an operating attachment mounted on the tip of the second arm. In an industrial vehicle further having a third arm, the second and third arms are driven in such a manner that the tip of the third arm will not deviate from the targeted locus as a result of the rotation of the first arm. At this juncture, the aforementioned feedback is also provided.

Apparatus for controlling arm movement of industrial vehicle

Growing community of inventors

Ibaragi, Japan

Kenichi Miyata