To provide an overload prevention system for a crane that is able to avoid increasing sheaves, and eliminate the need for extra winding work for a sheave dedicated for detecting load on a hoisting wire rope when a crane is installed and the need to lengthen the hoisting wire rope.SOLUTION: An overload prevention system for a crane comprises: a load detector 20 that measures a load; a jib angle detector 30 that measures an inclination angle θJ of a jib 5; and an overload prevention device 40 that has a set rating load curve for a work radius R for the jib 5, obtains a work radius R for the jib 5 on the basis of the inclination angle θJ of the jib 5, obtains a rating load from the rating load curve on the basis of the work radius R, obtains an actual load applied by a suspended load acting on a crane, on the basis of a load P measured by the load detector 20, and outputs an actuation stop signal for the crane in a case where the actual load exceeds the rating load. The load detector 20 is incorporated in a shaft of a sheave around which a hoisting wire rope 8 is wound.SELECTED DRAWING: Figure 1

    【課題】シーブの増加を避け、クレーンの設置時における巻上ワイヤロープの荷重検出専用のシーブに対する余分な掛け回し作業並びに巻上ワイヤロープを長くすることを不要とし得るクレーンの過負荷防止システムを提供する。【解決手段】荷重を計測する荷重検出器20と、ジブ5の傾斜角度θJを計測するジブ角度検出器30と、ジブ5の作業半径Rに対する定格荷重曲線が設定され、ジブ5の傾斜角度θJに基づきジブ5の作業半径Rを求め、作業半径Rに基づき定格荷重曲線より定格荷重を求め、荷重検出器20で計測された荷重Pに基づきクレーンに作用する吊荷による実荷重を求め、実荷重が定格荷重を超えていると判定された場合、クレーンの作動停止信号を出力する過負荷防止装置40とを備えたクレーンの過負荷防止システムであって、荷重検出器20は、巻上ワイヤロープ8が掛け回されるシーブの軸に組み込まれる。【選択図】図1


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    Title :

    OVERLOAD PREVENTION SYSTEM FOR CRANE


    Additional title:

    クレーンの過負荷防止システム


    Contributors:

    Publication date :

    2020-10-29


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    Japanese


    Classification :

    IPC:    B66C Krane , CRANES



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