| 摘要 |
A coin validator (1) is provided with at least two reference positions (U, D) for determining a diameter related characteristic of a coin being validated. In order to reduce the running to the testing station, the timing of a trailing point of the coin passing a first reference position (U) is used to determine the diameter related characteristic. Embodiments using optical (6, 8, 9, 11, 30, 32), inductive (50, 51, 52) and piezo-electric (55) sensors associated with the reference positions are disclosed. An inductive sensor (12) for a coin validator comprises an elongate coil, which, when in use, is arranged such that the magnetic field is substantially constant across the width of the passageway. The use of coils of this type have the advantage of wrap around coils but enable the coin passageway to be shallower and be opened. A coin validator (1) is described wherein the backwall of a coin passageway (2) is movable to and fro so that the depth of the coin passageway (2) can be adjusted. In an embodiment, a cam (63) bears against the backwall (62) of the coin passageway (2) to set the depth thereof.
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