Control apparatus and sensor

Claim 1

A FOLLOWER SENSOR FOR USE WITH A ROAD PAVING MACHINE HAVING A MOVABLE PAVING INSTRUMENTALITY ADAPTED TO BE CONTROLLED IN ACCORDANCE WITH A PRE-ESTABLISHED DATUM, AND HAVING; ELECTRICAL CONTROL MEANS HAVING OUTPUT MEANS ADAPTED TO CONTROL THE POSITION OF THE INSTRUMENTALITY, COMPRISING; A HOUSING ADAPTED TO BE MOUNTED ON THE MACHINE AND TO BE MOVABLE WITH MOVEMENT OF THE INSTRUMENTALITY, A SHAFT ROTATABLY MOUNTED WITHIN SAID HOUSING, A POTENTIOMETER HAVING A MOVABLE WIPER CONNECTED TO SAID SHAFT AND MOVABLE THEREWITH, MEANS ADAPTED TO CONNECT SAID POTENTIOMETER IN CONTROLLING RELATION TO THE ELECTRICAL CONTROL MEANS, A SNAP-ON MECHANICAL COUPLING MOUNTED ON SAID SHAFT, A FOLLOWER SENSOR MECHANICALLY MOUNTED ON SAID SHAFT BY VIRTUE OF SAID SNAP-ON COUPLING TO FACILITATE THE ACCIDENTAL STRIKING AND MECHANICAL DISENGAGEMENT OF SAID FOLLOWER SENSOR, SAID FOLLOWER SENSOR BEING ADAPTED TO FOLLOW THE DATUM TO CAUSE ROTATION OF SAID SHAFT AND A RESULTING MOVEMENT OF THE INSTRUMENTALITY AND SAID HOUSING, AND FURTHER ELECTRICAL CIRCUIT MEANS INCLUDING SAID SNAP-ON COUPLING AND EFFECTIVE TO BE ELECTRICALLY ACTUATED UPON ACCIDENTAL DISENGAGEMENT OF SAID FOLLOWER SENSOR.