Maeda Seisakusho Co., Ltd.

Tatsufumi Tomura

Ryosuke Nakamura

Shinya Tokutome

Eiji Ichimura

Mitsuaki Wada

Yuta Nishimaki

A crawler crane includes: a seating switch that detects whether an operator is in a driver seat; a turn angle potentiometer that detects the turn position of a boom; and a controller. The controller is provided with a boom turn restriction control unit for performing a boom turn-restricting control whereby the boom is not allowed to turn within a predetermined angular range above the driver seat on the basis of the output from the turn angle potentiometer. The boom turn restriction control unit includes a restriction-canceling unit that cancels the boom turn-restricting control performed by a turn-restricting unit if a preset restriction-canceling condition is met. The boom turn restriction control unit cancels the boom turn-restricting control if the seating switch does not detect an operator. Ease of operation and work can thus be improved in a remote operation mode and the like.

Mobile crane

In a crawler crane, while a fly jib is in use, the fly jib is suspended from a coupling flange by a jib raising/lowering wire rope that is wound around a sheave, the sheave being slidably attached to a tip end side section of the fly jib. If the sheave is caused to slide by a jib raising/lowering cylinder attached to the fly jib, the fly jib suspended from the coupling flange by the jib raising/lowering wire rope inclines with respect to a boom. The raising/lowering mechanism of the fly jib is installed on the fly jib side, thus making it possible to easily perform work to extract/store the fly jib.

Growing community of inventors

Nagano, Japan

Tatsufumi Tomura