Reading rate controlling machines

Claim 1

A DRIVING MECHANISM FOR THE SHUTTER OF A READING RATE CONTROLLING MACHINE COMPRISING A BASE, A CARRIAGE MOUNTED ON SAID BASE FOR RECIPROCAL MOVEMENT THEREALONG, A SHUTTER MOUNTED ON SAID CARRIAGE, A CLOCK-TYPE SPRING CONNECTED AT OPEN END OF SAID CARRIAGE, A DRUM ROTATABLY MOUNTED ON SAID BASE, THE OTHER END OF SAID CLOCK-TYPE SPRING CONNECTED TO SAID DRUM WHEREBY SAID SPRING IS ADAPTED TO WIND ABOUT SAID DRUM, A FIRST CORD DRUM MOUNTED ON SAID BASE COAXIAL WITH SAID SPRING DRUM AND ADAPTED TO FREELY ROTATE RELATIVE TO SAID SPRING DRUM, A CORD WOUND ON SAID CORD DRUM AND HAVING ONE END FIXED THERETO, A SECOND CORD DRUM ROTATABLY MOUNTED ON SAID BASE AROUND WHICH SAID CORD IS WOUND, SAID CORD HAVING ITS OPPOSITE END FIXED TO SAID CARRIAGE, A GEAR WHEEL MOUNTED ON SAID BASE COAXIAL WITH SAID SECOND CORD DRUM, A ONE-WAY DRIVE COUPLING BETWEEN SAID SECOND CORD DRUM AND GEAR WHEEL ADAPTED TO RELEASE THE COUPLING WHEN THE CARRIAGE IS MOVED IN ONE DIRECTION, ADJUSTABLE SPEED CONTROL MEANS COUPLED TO SAID GEAR WHEEL, AND A SECOND CLOCK SPRING MOUNTED ON SAID BASE HAVING ONE END CONNECTED TO SAID SPRING DRUM AND THE OTHER END CONNECTED TO SAID FIRST CORD DRUM TO PERMIT RELATIVE ROTATIONAL MOVEMENT BETWEEN SAID SPRING AND CORD DRUMS AND THEREBY COMPENSATE FOR VARIATION IN ROTATIONAL RATES OF SAID DRUMS.