Cable tension sensing apparatus

Apparatus for sensing the tension in a cable comprising a rocker pivotally supported on a member for rotation about a first axis;

• first means for biasing the rocker to a first rotational position;
• a slidable pulley rotatably carried by the rocker about a second axis substantially parallel to the first axis, means for slidably carrying the pulley on the rocker for linear movement between first and seocnd linear positions relative to the first axis upon tension being applied to the cable, second means for biasing the pulley to the first linear position, the cable being passed around the pulley and the second axis being located with respect to the first axis so as to cause the rocker to pivot away from said first rotational position and toward a second rotational position upon tension being applied to the cable, the second rotational position corresponding to a predetermined maximum desired cable tension;
• means for detecting the rocker being at the second rotational position;
• and means responsive to the detecting means for controlling the tension applied to the cable so as to maintain the tension less than or equal to said predetermined maximum desired tension.

Apparatus for maintaining the tension in a winch-controlled cable between minimum and maximum tension limits comprising a housing pivotally supported on a member for movement between first and second rotational positions, the housing having entrance and exit openings therein for the cable;

• first means for biasing the housing to the first rotational position;
• a pulley rotatably disposed within the housing with respect to the entrance and exit openings so as to enable the cable to be passed around the pulley and so as to cause the housing to pivot away from said first rotational position in accordance with the tension on the cable, the biasing means being selected such that the first rotational position of the housing corresponds to the minimum cable tension limit and such that the second rotational position of the housing corresponds to the maximum cable tension limit;
• first means for detecting the housing being at the first rotational position and for preventing operation of the winch to unwind the cable therefrom;
• and second means for detecting the housing being at the second rotational poisition and for preventing operation of the winch to wind up cable, the first means for biasing the housing comprises first and second plungers extending through the member upon which the housing is supported, and first and second springs for respectively biasing the first and second plungers into engagement with the housing, and wherein the first and second detecting means comprise first and second switches, the first switch being positioned with respect to the first plunger so as to be actuated for all rotational positions of the housing other than the first rotational position, and the second switch being positioned with respect to the second plunger so as to be actuated only upon the housing being at the second rotational position, the first spring has a length greater than the length of the second spring so that the first spring alone biases the housing toward the first rotational position for rotational positions of the housing between the first rotational position and an intermediate rotational position, and the second spring has a spring constant greater than the first spring and a length such that the second spring is compressed only for rotational positions of the housing between said intermediate position and the second rotational position, means for compensating for tension variations in the cable by slidably disposing the pulley within the housing for movement between first and second linear positions in a direction substantially parallel to the direction which the cable enters and exits the housing, and second biasing means for biasing the pulley away from the entrance and exit openings toward the first linear position.