Web width measuring and recording apparatus

Claim 1

IN A WEB WIDTH MEASURING DEVICE, A PAIR OF WANDS MOUNTED IN SPACED RELATION ON OPPOSITE SIDES OF THE PATH OF A CONTINUOUSLY MOVING WEB; SAID WANDS HAVING FINGER PORTIONS FOR CONTINUOUSLY CONTACTING RESPECTIVELY THE OPPOSITE EDGES OF THE WEB; MEANS FOR MOUNTING SAID WANDS FOR MOVEMENT RESPONSIVE TO MOVEMENT OF SUCH WEB EDGES WHEREBY LATERAL MOTION OF THE WEB WHICH CAUSES EQUAL MOVEMENT OF THE WANDS IN A COMMON DIRECTION PRODUCES NO CHANGE IN THE DISTANCE BETWEEN SAID FINGERS, BUT ANY CHANGE IN WEB WIDTH RESULTS IN AN UNEQUAL MOVEMENT OF THE WANDS IN OPPOSITE OR THE SAME DIRECTIONS, OR EQUAL WAND MOVEMENT IN OPPOSITE DIRECTIONS, OR MOVEMENT OF ONLY ONE WAND, THE OTHER REMAINING UNMOVED; A PAIR OF POTENTIOMETERS OPERATIVELY CONNECTED TO RESPECTIVE SAID WANDS FOR ADJUSTMENT THEREBY; A BALANCEABLE BRIDGE CIRCUIT IN WHICH SAID POTENTIOMETERS ARE CONNECTED SAID POTENTIOMETERS AND BRIDGE CIRCUITS BEING DESIGNED FOR ENERGIZATION BY DIRECT CURRENT; A SELVEDGE CORRECTION MEANS COMPRISING A PAIR OF VARIABLE RESISTORS CONNECTED TO SAID BRIDGE CIRCUIT IN OPPOSITE ARMS THEREOF, MEANS FOR MECHANICALLY OPERATIVELY INTERCONNECTING SAID RESISTORS FOR RESPONDING TOGETHER TO A COMMON ADJUSTMENT; AND MEANS RESPONSIVE TO THE EXTENT OF BRIDGE CIRCUIT UNBALANCE FOR INDICATING WEB WIDTH SAID MEANS BEING DIRECTLY RESPONSIVE TO SUCH UNBALANCE AND FREE OF AMPLIFYING MEANS TO AMPLIFY THE ENERGY REFLECTING SUCH UNBALANCE.