| 摘要 |
For discriminating between coins of substantially the same size but having different edge characteristics, in particular between faceted coins such as the British 50p piece and a false, round, smooth-edged coin having substantially the same effective diameter, the coin testing device throws light from a light emitter (10) onto the edge of a coin (6) passing along a coin path (4). Reflected light from the coin edge is detected by a light detector (12). The slope of the detector output signal indicates the nature of the edge characteristics of the coin. Because the emitter/detector unit (8) in effect measures the curvature of the portion of the coin edge presented to it, the invention also finds application for measuring the curvature and diameter of round coins. In a development the coin is treated as a faceted coin only if the test result, and also the result of a further, mean diameter, test, indicate diameters for the coin which are inconsistent with one another. <IMAGE> |
