Speed changing mechanism

Claim 1

A MULTIPLE SPEED DRIVE MECHANISM OF THE CHARACTER DESCRIBED COMPRISING A STEPPED DRIVE SPINDLE, A CYLINDRICAL DRIVEN MEMBER ROTATABLE ABOUT AN AXIS PARALLEL TO THE AXIS OF SAID SPINDLE, AN AXIALLY MOVABLE SHIFT LEVER ROCKABLE BETWEEN AN ADVANCED AND A RETRACTED POSITION, AN IDLER TRANSFER WHEEL MOUNTED ON SAID SHIFT LEVER AND MOVABLE THEREWITH INTO AND OUT OF ENGAGEMENT WITH SAID SPINDLE AND SAID DRIVEN MEMBER AS SAID LEVER IS IN ITS ADVANCED POSITION AND RETRACTED POSITION RESPECTIVELY AND AXIALLY MOVABLE THEREWITH TO LEVELS CORRESPONDING TO THAT OF THE SPINDLE STEPS, AN ARM PROJECTING FROM AND MOVABLE IN UNISON WITH SAID LEVER, A ROTATABLE CYLINDRICAL CAM HAVING AN END FACE HAVING A CONTOUR VARYING AXIALLY ALONG A PERIPHERAL PATH ENGAGING SAID ARM TO AXIALLY SHIFT SAID ARM UPON RELATIVE MOVEMENT BETWEEN SAID END FACE AND SAID ARM, AND A CIRCUMFERENTIALLY EXTENDING UPSTANDING TRACK LOCATED ON SAID CAM END FACE INWARDLY OF THE PERIPHERY THEREOF AND HAVING RECESSES FORMED THEREIN ADAPTED TO ENGAGE SAID ARM.