Linear measuring device

Claim 1

A GUAGING APPARATUS COMPRISING A SUPPORT, AN ELONGATED BAR MEMBER SLIDABLY MOUNTED ON SAID SUPPORT, A STATIONARY ANVIL MEMBER ON SAID SUPPORT OPPOSITE ONE END OF SAID BAR MEMBER, MAGNETIC MEANS ON SAID BAR MEMBER MAGNETIZED WITH UNIFORMLY LONGITUDINALLY-SPACED SIGNAL PULSES, STATIONARY MAGNETIC PICK-UP MEANS ON THE SUPPORT MOUNTED ADJACENT THE PATH OF MOVEMENT OF SAID FIRSTNAMED MAGNETIC MEANS ON DEVELOPING SIGNAL PULSES THEREIN CORRESPONDING TO SAID FIRST-NAMED SIGNAL PULSES RESPONSIVE TO LONGITUDINAL MOVEMENT OF THE BAR MEMBER, PULSECOUNTING MEANS CONNECTED TO SAID MAGNETIC PICK-UP MEANS, SAID BAR MEMBER BEING FORMED WITH LONGITUDINALLY-SPACED RACK TEETH, A PINION GEAR JOURNALED ON SAID SUPPORT MESHINGLY ENGAGING SAID RACK TEETH, A REVERSIBLE ELECTRIC MOTOR MOUNTED ON SAID SUPPORT AND HAVING A FORWARD DRIVE WINDING AND A REVERSE DRIVE WINDING, MEANS TO SELECTIVELY ENERGIZE SAID WINDINGS, MEANS DRIVINGLY-CONNECTING SAID MOTOR TO SAID BAR MEMBER, NORMALLY-CLOSED SWITCH MEANS IN CIRCUIT WITH SAID REVERSE WINDING, SAID SWITCH MEANS BEING MOUNTED ON THE SUPPORT AND BEING PROVIDED WITH A MOVABLE OPERATING MEMBER, AND MEANS ON SAID BAR MEMBER DRIVINGLY-ENGAGEABLE WITH SAID OPERATING MEMBER RESPONSIVE TO THE MOVEMENT OF SAID BAR MEMBER TO A PREDETERMINED RETRACTED POSITION RELATIVE TO SAID ANVIL MEMBER, WHEREBY TO OPEN THE SWITCH MEANS AND DE-ENERGIZE SAID REVERSE WINDING WHEN THE BAR MEMBER REACHES SAID PREDETERMINED RETRACTED POSITION.