Tape tension motor control circuit

Claim 1

IN COMBINATION FOR USE WITH A MOVABLE MEDIUM, A CONTROL SYSTEM FOR MAINTAINING THE TENSION IN THE MOVABLE MEDIUM AT A DESIRED VALUE, INCLUDING, CONTROL MEANS OPERATIVELY COUPLED TO THE MEDIUM FOR EXERTING A DRIVING FORCE ON THE MEDIUM IN FIRST AND SECOND OPPOSITE DIRECTIONS IN AC CORDANCE WITH THE DIRECTION AND THE DEGREE OF EXCITATION OF THE CONTROL MEANS, MEANS RESPONSIVE TO THE MOVEMENT OF THE MEDIUM FOR PRODUCING CONTROL SIGNALS HAVING AN AMPLITUDE ON ONE SIDE OF A PARTICULAR VALUE FOR TENSIONS IN THE MOVABLE MEDIUM IN EXCESS OF THE DESIRED VALUE AND HVING AN AMPLITUDE ON THE OTHER SIDE OF THE PARTICULAR VALUE FOR TENSIONS LOWER THAN THE DESIRED VALUE, SWITCHING MEANS HAVING FIRST AND SECOND STATES OF OPERATION AND RESPONSIVE TO THE CONTROL SIGNALS TO BECOME OPERATIVE IN THE FIRST STATE FOR CONTROL SIGNALS WITH AN AMPLITUDE ON ONE SIDE OF THE SAID PARTICULAR VALUE AND TO BECOME OPERATIVE IN THE SECOND STATE OF OPERATION FOR CONTROL SIGNALS WITH AN AMPLITUDE ON THE OTHER SIDE OF THE SAID PARTICULAR VALUE, MEANS RESPONSIVE TO THE CONTROL SIGNALS FOR TRANSPOSING CONTROL SIGNALS ON ONE SIDE OF THE PARTICULAR VALUE TO A CORRESPONDING POSITION ON THE OTHER SIDE OF THE PARTICULAR VALUE TO OBTAIN SIGNALS OF EQUAL AMPLITUDE FOR CORRESPONDING DEVIATIONS IN TENSIONS ON BOTH SIDES OF THE DESIRED VALUE, AND MEANS RESPONSIVE TO CHANGES IN THE STATES OF OPERATION OF THE SWITCHING MEANS BETWEEN THE FIRST AND SECOND STATES TO CHANGES THE DIRECTION OF EXCITATION OF THE CONTROL MEANS AND RESPONSIVE TO THE TRANSPOSED CONTORL SIGNAL TO CHANGE THE DEGREE OF EXCITATION OF THE CONTROL MEANS IN ACCORDANCE WITH TEH AMPLITUDE OF THE TRANSPOSED CONTROL SIGNAL.