Pocket calculator for digital tape measurements - has pulse generator driven by tape to provide input to circuitry for total measure

摘要

The pocket calculator has a keyboard (2) and a digital display (3) mounted on a front facia with the necessary electronic circuitry mounted on a card (4) in the base of the unit. The tape (7) is wound onto a spool (5) and passes through a slot in the side wall. A control roller e.g. friction wheel, carries a rotary pulse generator that emits pulses when the tape is drawn out of the unit. The electronic circuitry totalises the pulses generated to provide a display of the tape length. A battery (9) provides power for the electronic circuits.