Cable-driven extension mechanism for trailer slide-out

Abstract

Apparatus for selectively extending and withdrawing a trailer slide-out portion includes first and second rails, each slidably supported in a channel mounted underneath the trailer body. The outer ends of the rails are attached to the underside of the slide-out portion. A sheave driven by a reversible motor is mounted between the channels. First and second cables are wrapped around the sheave, the first cable having its ends attached to the first rail, and the second cable having its ends attached to the second rail. A pulley assembly supports each of the cables as it passes from the sheave to its respective rail. The cables, in conjunction with the pulley assemblies, translate the rotation of the sheave into longitudinal motion of the rails through the channels. Thus, sheave rotation in a first direction causes the cables to pull the rails outwardly, extending the slide-out, while sheave rotation in the opposite direction causes the cables to pull the rails inwardly, withdrawing the slide-out. A slack-compensation attachment device attaches each of the cables to its respective rail, whereby slack resulting from cable stretching is taken up. A shaft is provided, having a first end coupled to the sheave and a second end engageable by a hand crank, for allowing manual rotation of the sheave.