Abstract: An apparatus is described for detecting a slack cable condition on material handling carriers, hoisting equipment and the like. The device is mounted adjacent the winch drum and is designed for disabling the operation of the winch when the load comes to rest and the cable slackens. When a load is being supported by the cable and the cable is taut, an interface portion of the sensing apparatus is biased to a first position. However, when the load comes to rest and the cable slackens, a bias spring functions to position the interface portion of the sensor to a second position and to preclude further operation of the winch and prevent undesirable cable unwinding.

Abstract: A straddle type mobile crane includes a steering system which allows two-wheel or four-wheel steering. A first steering cylinder is associated with each wheel for four-wheel operation and an additional cylinder is associated with each of a first pair of wheels for two-wheel steering. An interlock system has a first mode for four-wheel drive wherein each wheel is coupled to its associated first steering cylinder and a second mode wherein each wheel is uncoupled from each first cylinder and each of the first pair of wheels are coupled to one of the additional cylinders and the other pair of wheels are locked to the frame. A first control prevents operation of the interlock unless the wheels are in predetermined orientation and a second control maintains proper alignment of the wheels in all angular positions.