Tape loop control

Claim 1

IN A TAPE TRANSPORT, A MOTOR, A CAPSTAN DRIVEN BY SAID MOTOR, A SECOND MOTOR, A STORAGE REEL FOR THE TRANSPORT OF TAPE DRIVEN BY SAID SECOND MOTOR, A VACUUM LOOP BOX FOR THE STORAGE OF A LOOP OF TAPE BETWEEN SAID CAPSTAN AND SAID REEL, A REEL MOTOR CONTROL COMPRISING A PLURALITY OF VACUUM SWITCHES FOR DETECTING THE LENGTH OF SAID LOOP, EACH OF SAID SWITCHES BEING COUPLED TO SAID LOOP BOX SO THAT IT RESPONDS TO THE PRESSURE AT A DIFFERENT INTERIOR POINT ALONG THE LENGTH OF THE LOOP BOX, SIGNAL PRODUCING MEANS OPERABLE IN RESPONSE TO THE SELECTIVE ACTUATION OF SAID SWITCHES BY THE VACUUM BELOW SAID LOOP TO PRODUCE A SIGNAL PROPORTIONAL TO THE LENGTH OF THE TAPE LOOP IN SAID LOOP BOX, CONTROL MEANS OPERABLE IN RESPONSE TO THE DEVIATION OF SAID SIGNAL FROM A PREDETERMINED RELATIONSHIP WITH A SIGNAL REPRESENTING A DESIRED LOOP LENGTH TO ENERGIZE SAID SECOND MOTOR DRIVING SAID REEL IN DIRECTION AND AMOUNT DEPENDING ON THE POLARITY AND MAGNITUDE OF SAID DEVIATION TO CHANGE SAID LOOP LENGTH TOWARD SAID DESIRED VALUE.