Method and device for changing prestress of lifting arm of flat-head tower crane

A technology for flat-top tower cranes and booms, applied in the field of a method and its devices, can solve the problems of large boom bending moment and weaken the lifting capacity of flat-top tower cranes, and achieve the effect of improving the lifting capacity
CN102633196AActive Publication Date: 2012-08-15SHANDONG FORYOU +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHANDONG FORYOU
Publication Date
2012-08-15

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Abstract

The invention relates to the technical field of a flat-head tower crane, in particular to a method and a device for changing prestress of a lifting arm of the flat-head tower crane. An inhaul cable structure is arranged on each of a balance arm and a lifting arm; the computational formula of the inhaul cable pulling force of the lifting arm is obtained according to the moment balance principle; so that the component force of the inhaul cable pulling force of the lifting arm on the vertical direction causes a bending moment on the root part of the lifting arm opposite to the gravity and loading direction of the lifting arm; and the bending moment can enable the lifting arm to generate a prestress. Therefore, the pulling force of the lifting arm inhaul cable can be changed by adjusting the position of the hinged points of the inhaul cable and the balance arm or the lifting arm to further change the prestress of the lifting arm so as to improve the lifting capacity of the lifting arm.
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Description

technical field

[0001] The invention relates to the technical field of flat-top tower cranes, in particular to a method for changing the prestress of a jib of a flat-top tower crane and a device used therefor. Background technique

[0002] Tower crane is an important equipment for the modern construction industry to realize production mechanization and automation, reduce physical labor intensity and improve production efficiency. Flat-top tower cranes without tower caps are more and more used in the construction industry due to their advantages such as low installation height, simple loading and unloading, and simple stress on the steel structure of the boom and long life. However, the mass of the boom and balance arm of the flat-top tower crane is 5% to 15% heavier than that of ordinary tower cranes of the same level, resulting in a large downward bending moment of the boom, which greatly weakens the lifting capacity of the flat-top tower crane. Contents of the invention ...

Claims

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