(19)
(11) EP 0 300 781 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
31.01.1990 Bulletin 1990/05

(43) Date of publication A2:
25.01.1989 Bulletin 1989/04

(21) Application number: 88306690.4

(22) Date of filing: 21.07.1988
(51) International Patent Classification (IPC)4: G07D 5/08, G07F 3/02
(84) Designated Contracting States:
AT BE CH DE ES FR GB GR IT LI LU NL SE

(30) Priority: 23.07.1987 GB 8717493

(71) Applicant: SCAN COIN AB
S-213 75 Malmö (SE)

(72) Inventor:
  • Howells, Geoffrey
    Cosham Portsmouth Hampshire, PO6 2ST (GB)

(74) Representative: Lomas, Geoffrey Michael et al
BARKER, BRETTELL & DUNCAN 138 Hagley Road Edgbaston
Birmingham B16 9PW
Birmingham B16 9PW (GB)


(56) References cited: : 
   
       


    (54) Coin discriminator


    (57) A coin (5) under test is subjected to the changing magnetic field produced by pulsing of a test coil (1), and the decay of the resulting eddy currents in the coin is monitored by monitoring the coil voltage induced by the eddy currents. The times T₁ and T₂ at which the coil voltage falls through voltage levels V₁ and V₂ is measured by comparators (COMP 1, COMP 2) and a microcomputer (7), and those times are compared by microcomputer (7) with stored reference values to help determine the coin type.







    Search report