The invention discloses an accessory arm of a crane, a lifting arm of a crane, and a crane. The accessory arm comprises a rotating arm part and an accessory-arm amplitude varying oil cylinder for driving the rotating arm part to rotate so as to enable the accessory arm to vary amplitude, wherein the accessory-arm amplitude varying oil cylinder is provided with a rodless cavity and a rod cavity. The accessory arm is characterized in that the accessory-arm amplitude varying oil cylinder adopts the rodless cavity as a working cavity for supporting the rotating arm part at a working position. According to the accessory arm disclosed by the invention, when the accessory-arm amplitude varying oil cylinder supports the rotating arm part at the working position, the large cavity is used as the working cavity, and a cylinder rod is in a pressed state, so that when internal leakage occurs on the accessory-arm amplitude varying oil cylinder of the accessory arm, because the direction of the pressure generated by oil liquid is opposite to the direction of the external carrying force applied on the cylinder rod, the position of the cylinder rod can be basically unchanged; therefore, the position of the rotating arm part of the accessory arm can be basically unchanged; the phenomenon that the support of the accessory-arm amplitude varying oil cylinder to the rotating arm part of the accessory arm loses efficacy is avoided, so that the accessory arm disclosed by the invention solves the problem that because the internal leakage occurs on the accessory-arm amplitude varying oil cylinder of a drawing-cylinder variable-amplitude accessory arm in the prior art, safety risks are generated.
Accessory arm and lifting arm of crane, and crane
2015-11-18
Patent
Electronic Resource
English
IPC: | B66C Krane , CRANES |