Device for coin checking

Device for coin checking, characterized by

• a coin guide (31, 32) for the coins to be tested;
• a plurality of oscillator tank circuits (1-6) each having a sensing coil (7-12);
• said sensing coils (7-12) of said tank circuits (1-6) are shaped and arranged along said guide (31-32), so that different sensing coils are sequentially influenced in dependence of different characteristics of the coin to be tested, when it travels along said guide (31, 32);
• an amplifier (14);
• a switching unit (16, 17), by means of which each of the plurality of oscillator tank circuits (1-6) can be connected individually to said amplifier (14) for the formation of an oscillator;
• a control unit (28) controlling said switching unit (16, 17) for sequentially connecting said tank circuits (1-6) to said amplifier (14);
• testing means (19) responsive to the oscillator oscillations which (19) yields test signals (P1, P2, d1, d2, L, S) for different coin characteristics, corresponding to the influence exerted by the coin to be tested on the sensing coil (7-12) of the respective oscillator tank circuit of said plurality of oscillator tank circuits (1-6);
• a memory (23) in which criteria are stored for each of the test signals as obtained with the coin types to be accepted;
• and an evaluating unit (22) connected to said testing means (19) and said memory (23) for comparing these test signals with these criteria stored in said memory (23), and delivering a coin acceptance signal, in case all test signals obtained for the various coin characteristics of one and the same coin to be tested, correspond to the criteria stored for these characteristics of one and the same acceptable coin.