Method and apparatus guiding retractable machinery
 A retractable tool apparatus is adapted to be mounted on a movable vehicle for working the area around and between objects in a row. The tool apparatus includes an extendable and retractable outrigger arm attachable on one of its ends to the vehicle. A work tool is mounted on the other end of the outrigger arm. An electro-hydraulic control system controls the retraction of the outrigger arm. This control system includes sensors in the form of a pair of wands mounted on the outrigger arm to sense objects in proximity to the work tool before the work tool contacts the objects. The first wand activates the control system upon contact with an object to retract the work tool. The second wand holds the control system in its retraction mode upon contact with the object even after the first wand has cleared the object. 
A
A01B
inventional
Jack F. Clayton
Anderson Melrose