Metric, english converter for machine tools

Claim 1

IN COMBINATION, A MACHINE TOOL HAVING (A) A ROTATABLE SHAFT, (B) FIRST SCALE MEANS HAVING UNIT MARKS THEREON AND A COOPERATING POINTER, (C) A DIRECT DRIVING CONNECTION BETWEEN SAID SHAFT AND SAID SCALE MEANS FOR MOVING THE SCALE MEANS TO INDICATE AN INTEGRAL UNIT DISTANCE ON THE SCALE MEANS WHEN THE SHAFT MOVES A COMPLETE REVOLUTION, (D) SECOND SCALE MEANS HAVING DIFFERENT UNIT MARKS FROM THE FIRST SCALE MEANS AND A COOPERATING POINTER, (E) GEAR TRAIN MEANS MECHANICALLY INTERCONNECTING SAID SHAFT AND SAID SECOND SCALE MEANS, THE GEAR RATIO BEING SUCH THAT THE SHAFT MOVES A COMPLETE REVOLUTION WHEN SAID SECOND SCALE MEANS MOVES A UNIT DISTANCE ON THE SECOND SCALE MEANS, (F) MANUAL DRIVER MEANS FOR SAID SHAFT, (G) SELECTIVELY OPERABLY COUPLING MEANS BETWEEN SAID DRIVER MEANS AND THE SHAFT, (H) SAID COUPLING MEANS HAVING TWO OPERATIVE CONDITIONS (1) IN ONE OF SAID CONDITIONS COUPLING SAID DRIVER MEANS DIRECTLY TO THE SHAFT TO MOVE THE SHAFT IN UNISON WITH MOTION OF THE DRIVER, (2) IN THE OTHER OF SAID CONDITIONS COUPLING THE DRIVER MEANS TO SAID SECOND SCALE MENAS TO MOVE THE SHAFT THROUGH SAID GEAR TRAIN WITH MOTION OF THE DRIVER.