Tractor with ground rotated member and driven wheel revolution counters and implement lift means operatively connected thereto

Claim 1

A tractor comprising an engine, wheels driven by said engine, a lifting device for attachment of an implement, sensing means including a ground rotated member, control means comprising two like counters which operatively continuously count revolutions of at least one of said driven wheels and the equivalent revolutions of said ground rotated member from a common starting point and comparator means for providing a signal when there is a preset difference between the respective counted revolutions of said one wheel and the counted said equivalent revolutions of said ground member without regard to the specific respective rotational speeds of said one wheel and said ground member as such, said lifting device including lifting means for raising an implement when attached thereto, means for energizing said lifting means to raise an implement when attached thereto, an operative connection between said control means and said energizing means which is adapted to cause said lifting means to be energized and to raise an implement when attached thereto upon receiving said signal, and means for resetting said counters to said starting point after said lifting means has been energized, each said counter independently counting from its starting point to capacity and returning to zero to continue counting until reset by said resetting means.