loppers has to be engaged by teeth

摘要

A pruning hook comprises an extension shank10, a driven arm20pivotally connected with the extension shank, a driving arm30pivotally connected with the extension shank and engaging the driven arm, an operation cord35mounted between the driving arm and the extension shank, an elastic member34biased between the driving arm and the extension shank, and a limit plate40abutting the driving arm and the driven arm to limit the driving arm and the driven arm between the extension shank and the limit plate. The driven arm has an end provided with a toothed rack and the driving arm has a side provided with a toothed driving rack which meshes with the rack of the driven arm. Thus, the driven arm and the driving arm have different pivot centers, and the total arm length of the driven arm and the driving arm has a larger force arm and a larger torque.