Patent ID: 6854715
Filing Date: 2005-02-15
Classification: B66F

Abstract:
1. An anti fall device for use with scissor type mechanically actuated lifting devices, said anti fall device comprising: a) a means for arresting descent of the lifting device when the lifting device is normally stationary or moving upwardly and a drive assembly of the lifting device fails and the lifting device begins to descend uncontrollably; and b) wherein said arresting means including a slave safety hydraulic cylinder operably connected to the lifting device capable of supporting the lifting device upon failure of the drive assembly; (c) wherein said slave safety hydraulic cylinder including a one way check valve for preventing reverse hydraulic fluid flow upon uncontrolled descent of the lifting device thereby arresting movement of said slave safety hydraulic cylinder and arresting descent of the lifting device; and d) wherein said drive assembly including a ball screw/ball nut type mechanical drive.