Maeda Seisakusho Co., Ltd.

Mitsuaki Wada

Shinya Tokutome

Ryosuke Nakamura

Eiji Ichimura

Tatsufumi Tomura

Takahisa Karasawa

In this boom slewing angle detection device, a slewing angle detecting gear is attached to an end of a shaft of a pinion gear that meshes with a ring gear formed on a slewing bearing rotatably supporting a crane boom, and the amount of rotation of the slewing angle detecting gear is detected by a slewing-angle-detecting proximity sensor. The slewing angle detecting gear is not meshed with the ring gear or the pinion gear, which compose a slewing force transmission mechanism; thus, grease, and the like, do not adhere to the slewing angle detecting gear, and external teeth for detection of the slewing angle detecting gear are not subject to wear, so accurate slewing angle detection is possible.

Boom slewing angle detection device for mobile crane

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.

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Nagano, Japan

Mitsuaki Wada