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RATCHET MECHANISM OF A PRECISION REVOLUTION COUNTER

When spindle 1 is connected to the shaft whose revolutions are to be counted, worm 11, worm wheel 2 and gear 3 begin to rotate. When button a is pressed, pawl 4 is disengaged from ratchet wheel 5 which is keyed to a shaft with flat spring 6 and begins to rotate due to friction between the spring and gear 3. This leads to rotation of gears 7, 8, 9 and 10 which transmit rotation to hands b and c. Th…