US Patent 7624967 Opposed-rope hoist driven telescoping mast

An opposed-rope driven telescoping mast assembly includes a stationary support and a longitudinal mast comprising a longitudinal section joined to move relative to the stationary support. A drive assembly drives the longitudinal mast and includes a frame and a rotatable drum assembly mounted to the frame. A first rope is joined to the drum assembly and to the longitudinal mast to pull the longitudinal section in a first direction, while a second rope is joined to the drum assembly and to the longitudinal mast to pull the longitudinal section in a second direction. A sensor is operably coupled to the drive assembly to sense overload tension in the first rope or the second rope.