Echo-ranging devices

Claim 1

A VARIABLE SPEED DRIVE MECHANISM COMPRISING: A RING GEAR; A FIRST SUN GEAR LOCATED EXTERNAL TO SAID RING GEAR; A SECOND SUN GEAR LOCATED WITHIN SAID RING GEAR; AN OUTPUT SHAFT ATTACHED TO SAID FIRST AND SECOND SUN GEARS; A FIRST GEAR MEANS COUPLED TO THE OUTER RIM OF SAID RING GEAR EXTERNAL TO SAID OUTPUT SHAFT FOR SELECTIVELY ROTATING SAID RING GEAR AT A FIRST SPEED IN A FIRST DIRECTION; A SECOND GEAR MEANS COUPLED TO THE OUTER RIM OF SAID FIRST SUN GEAR EXTERNAL TO SAID OUTPUT SHAFT FOR SELECTIVELY ROTATING SAID FIRST SUN GEAR AT A SECOND SPEED IN SAID FIRST DIRECTION; MEANS FOR CHANGING THE DIRECTION OF ROTATION OF AT LEAST ONE OF SAID GEARS; AND, A PLANETARY GEAR ATTACHED TO SAID OUTPUT SHAFT AND COUPLED TO SAID RING AND SECOND SUN GEARS, SAID PLANETARY GEAR CAUSING SAID OUTPUT SHAFT TO ROTATE AT A THIRD SPEED IN SAID FIRST DIRECTION WHEN SAID FIRST GEAR MEANS IS ROTATING SAID RING GEAR AND SAID SECOND GEAR MEANS IS NOT ROTATING SAID FIRST SUN GEAR, AT A FOURTH SPEED IN SAID FIRST DIRECTION WHEN SAID FIRST GEAR MEANS IS NOT ROTATING SAID RING GEAR AND SAID SECOND GEAR MEANS IS ROTATING SAID FIRST SUN GEAR, AND AT A SPEED PROPORTIONAL TO THE ALGEBRAIC SUM OF SAID THIRD AND FOURTH SPEEDS WHEN SAID FIRST GEAR MEANS IS ROTATING SAID RING GEAR AND SAID SECOND GEAR MEANS IS ROTATING SAID FIRST SUN GEAR.