Importance

Loading Importance Indicators...

Abstract

A drum for winding a cable attached to an overhead door includes a hub having a central aperture for accepting a shaft, a radially extending boss formed on the hub and a threaded aperture extending through the boss for retaining a threaded fastener for releasably attaching the hub to a shaft extending through the central aperture, a web attached in a central portion of the hub, the web extending radially outwardly at an angle of approximately 60.degree. with respect to the longitudinal axis of the hub, and a cable support extending about and being attached to the web, the cable support having a multiturn generally helical cable winding groove formed in an outer surface thereof. The cable winding groove includes a first portion spaced a first predetermined constant radius from the longitudinal axis of the hub, a second portion extending from the first portion and a third portion extending from the second portion, the third portion being spaced a second predetermined constant radius from the longitudinal axis of the hub, the first radius being larger than the second radius and the second portion being spaced from the longitudinal axis by a variable radius uniformly decreasing from the first radius to the second radius. A cable entry slot is formed adjacent one end of the first groove portion and includes a cavity having a pair of generally parallel side walls extending at an angle of approximately 2.degree. 30' with respect to a pair of side walls of the groove.

Loading the Abstract Image...

First Claim