Apparatus for positioning stage drops

Claim 1

IN AN APPARATUS UTILIZING A SOURCE OF ENERGIZING POTENTIAL FOR RAISING AND LOWERING A STAGE DROP THE COMBINATION WHICH COMPRISES A MOVABLE ELONGATED SUPPORT MEMBER FOR SUPPORTING THE STAGE DROP, A HEAD BLOCK, AN ARBOR DISPOSED BELOW THE HEAD BLOCK, WEIGHTS CARRIED BY THE ARBOR FOR BALANCING THE STAGE DROP, A PLURALITY OF FLEXIBLE SUPPORTING CABLES DISPOSED OVER THE HEAD BLOCK AND CONNECTED AT ONE END TO THE SUPPORT MEMBER AND AT THE OTHER END OF THE ARBOR, A CONTROL CABLE CONNECTED AT EACH END TO THE ARBOR, MEANS FOR SUPPORTING THE CONTROL CABLE ABOVE THE ARBOR SO THAT THE ARBOR IS MOVED IN A DOWNWARD DIRECTION WHEN THE CONTROL CABLE IS MOVED IN ONE DIRECTION AND THE ARBOR IS MOVED IN THE UPWARD DIRCTION WHEN THE CONTROL CABLE IS MOVED IN THE OTHER DIRECTION, A ROTATABLY MOUNTED DRIVE MEMBER DISPOSED IN ENGAGEMENT WITH THE CONTROL CABLE SO THAT THE CONTROL CABLE IS MOVED WHEN THE DRIVE MEMBER IS ROTATED, AN ELECTRIC MOTOR, AN ELECTRICALLY ACTUATED CLUTCH CONNECTED BETWEEN THE DRIVE MEMBER AND THE MOTOR, A MOTOR CONTROL CIRCUIT CONNECTED BETWEEN THE SOURCE OF ENERGIZING POTENTIAL AND THE MOTOR TO SUPPLY ENERGIZING CURRENT TO THE MOTOR TO SELECTIVELY DRIVE THE MOTOR IN A FORWARD AND REVERSE DIRECTION TO RAISE AND LOWER THE STAGE DROP, MEANS FOR CONNECTING THE CLUTCH TO THE SOURCE OF ENERGIZING POTENTIAL FOR THE MOTOR SO THAT THE CLUTCH CONNECTS THE MOTOR TO THE DRIVE MEMBER IN RESPONSE TO THE ENERGIZING POTENTIAL AND DISCONNECTS THE MOTOR FROM THE DRIVE MEMBER IN THE ABSENCE OF THE ENERGIZING POTENTIAL, THE LAST NAMED MEANS BEING ARRANGED TO SELECTIVELY ENERGIZE THE CLUTCH WITH AA FIRST AND SECOND PREDETERMINED ENERGIZING CURRENT SO THAT WHEN THE CLUTCH IS ENERGIZED WITH THE FIRST PREDETERMINED ENERGIZING CURRENT THE CLUTCH WILL CONNECT THE MOTOR TO THE DRIVE MEMBER TO MOVE THE ARBOR IN A DOWNWARD DIRECTION EVEN THROUGH THE WEIGHTS ON THE ARBOR DO NOT BALANCE THE STAGE DROP AND WHEN THE CLUTCH IS ENERGIZED BY THE SECOND PREDETERMINED CURRENT THE CLUTCH WILL CONNECT THE MOTOR TO THE DRIVE MEMBER ONLY WHEN THE WEIGHTS ON THE ARBOR APPROXIMATELY BALANCE THE STAGE DROP.