US Patent:
20060096720, May 11, 2006
Inventors:
LeRoy Krupke - Carrollton TX, US
Marius Suchici - Lewisville TX, US
Assignee:
OVERHEAD DOOR CORPORATION - FARMERS BRANCH TX
International Classification:
E05F 11/00
Abstract:
A counterbalance system for an upward acting door includes a cable drum support shaft and a torsion spring drive mechanism mounted adjacent one or both sides of the door and drivably connected to the drum support shaft. The spring drive mechanism includes a torsion coil spring mounted on a frame and connected to a vertically oriented shaft which, in turn, is connected to an output shaft by way of a bevel gear drive. A spring winder device is connected to one end of the spring and to the frame. Indicia on the spring is viewable through a window on the mechanism frame for indicating the number of revolutions imposed on the spring to set a predetermined counterbalance torque.