Kabushiki Kaisha Kobe Seiko Sho

Tsuyoshi Katada

Yukio Koizumi

Norihiko Hayashi

Yoshimi Saotome

Kiyotsuna Kuchiki

A steering controlling device for a wheel crane wherein a locking operation in a special mode is permitted upon changing over from the special mode to a normal mode and locking and a mode changing over operation can be prevented during normal running of the crane. The device includes front and rear wheel steering cylinders, a mode changing over valve for controlling the cylinders to change over the steering mode, a mode selecting switch, a locking device for locking the rear wheels in the normal mode, a locking switch, a running detecting sensor for detecting a running condition of the crane, a locking change-over controller means responsive to signals from the locking switch and the running detecting sensor for developing a locking or unlocking instruction signal to the locking device when the crane is not in a normal running condition, and a mode change-over controller means responsive to a signal from the running detecting means for forwarding a steering mode selected by the mode selecting switch to the mode changing over valve when the crane is not in a normal running condition.

Steering controlling device for wheel crane

An apparatus for damping quaky movements of a mobile type crane includes the prohibition of the formation of a closed damping circuit through the opposing oil chambers of a boom uplifting cylinder in working mode or a crane operation in travel mode of the crane, enhancing safety in crane operation while ensuring effective quake damping action in vehicle travel. The apparatus includes a vehicle body supported on driven wheels; a boom pivotally supported on the vehicle body through a hydraulic cylinder for pivoting movements about a horizontal shaft; main hydraulic pumps connected through a transmission mechanism to an engine mounted on the vehicle body and switchable between on- and off-positions; a direction control valve for selectively supplying and draining the discharge oil pressures of the main pumps to and from a first load-holding main oil chamber and an opposing second oil chamber of the cylinder; a counter-balancing valve provided between the cylinder and directionh control valve; an accumulator provided between the cylinder and counter-balancing valve for suppressing quaky movements of the vehicle body; a mode selector means for switching the mode of operation between a vehicle travel mode forming a closed circuit through the first and second oil chambers and in communication with the accumulator, and a working mode cancelling the closed circuit and supplying and draining oil pressures separately to and from the first and second oil chambers; and a controller adapted to permit a switch to the travel mode position of the travel mode selector only when the main pumps are in an off state.

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Kakogawa, Japan

Tsuyoshi Katada