| 摘要 |
<p>A coin selector (1) comprises an inlet (2) for a coin (3) to roll along a channel guide (4) past three magnetic sensors (5, 6, 7) in turn. Between the three magnetic sensors (5, 6, 7) are two position detectors (8, 9). Each position detector (8) preferably comprises an infra-red light optic sensor and detects when the coin (3) first interferes with its light beam or ceases to interfere with its light beam and hence causes an associated sensor to take a reading when the coin (3) is in a predetermined position, reducing or eliminating error due to bouncing of the coin. The sensors test the coin for its diameter, cross section and alloy. One magnetic sensor is electromagnetic with a ferromagnetic core, one is electromagnetic with an air core and the third is electromagnetic with a ferromagnetic core of disperse magnetic field. <IMAGE></p> |
