US 5,957,989 AGranted

Interference preventing system for construction machine

AssigneeHitachi Construction Machinery Co., Ltd.

InventorsEiji Egawa, Hiroshi Watanabe, Hiroyuki Adachi, Junichi Hosono, Toshiaki Nishida, Mitsuo Kihara, Masakazu Haga

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Abstract

A calculating portion 7a calculates a distance from the tip end of a front device to an interference prevention area, and a detection line 7m detects a moving speed of a boom 1. If the tip end of the front device comes close to the interference prevention area when the boom 1 is moving upward, control is made such that, while continuing to move the boom 1 upward, a control gain calculating portion 7h and a multiplier 7i cooperatively calculate a target speed of an arm in the arm dumping direction (interference avoiding direction) corresponding to the boom-up speed, and an input limit value calculating portion 7c, an adder 7j and a minimum value selecting portion 7f cooperatively control the arm to move in the interference avoiding direction relative to a vehicle body. Interference avoidance control enabling the tip end of the front device to be moved smoothly along the vicinity of a boundary of the interference prevention area is thereby effected and the front device can be prevented from interfering with the vehicle body without reducing the maneuverability and the working efficiency.

Claims31

Dependent claims

An interference preventing system for a construction machine comprising a vehicle body, a front device mounted on said vehicle body and made up of a plurality of front members including first and second front members pivotable in the vertical direction, a plurality of hydraulic actuators for driving said plurality of front members, a plurality of operating means for instructing operations of said plurality of front members, and a plurality of flow control valves for controlling flow rates of a hydraulic fluid supplied to the associated hydraulic actuators in accordance with respective operation signals input from said plurality of operating means, said interference preventing system regulating motion of said front device when said front device come close to said vehicle body, wherein said interference preventing system comprises:

(a) first detecting means for detecting status variables in relation to a position and attitude of said front device,
(b) calculating means for calculating the position and attitude of said front device based on detected values of said first detecting means,
(c) second detecting means for detecting the operation of said first front member in accordance with the operation signal from said operating means, and
(d) first control means for controlling, based on a calculated value of said calculating means and a detected value of said second detecting means, said second front member to move in the interference avoiding direction relative to said vehicle body while continuing to operate said first front member in accordance with said operation signal, when a predetermined portion of said front device comes close to said vehicle body while said first front member is being moved in accordance with said operation signal.

1 more element

Dependencies are inferred from the claim text.