Scan Coin Industries Ab

Geoffrey Howells

A coin discriminator measures both the surface and average electrical conductivity of coins in order to distinguish genuine minted coins from fake or bogus coins such as cast coins which may be nominally of the same material as a minted coin. The conductivities are measured using a coil to induce eddy currents within the coin. The high frequency components of the eddy current are monitored to measure the surface conductivity. The low frequency components are measured to monitor the bulk or average conductivity.

Coin discriminators

A coin processing machine with a coin discriminator operated by a method is provided. The coin discriminator measures how a coin having an iron core covered by a layer of copper, brass, or bronze affects a coil when the coin is subjected to magnetic fields generated by the coil, external to the coin. Eddy currents induced in the coin are detected external of the coin. The discriminator induces a magnetic field in the coil by driving the coil with time varying drive signals having high frequencies. The coin discriminator receives the coin at precise positions in the magnetic field and detects the eddy currents induced in the coin by measuring the eddy currents through the coil. Then, the coin discriminator compares the measured eddy currents with predetermined values for different types of coils, and determines the structure, materials and type of the coin.

Coin discriminator where frequencies of eddy currents are measured

A coin discriminator has a coin path along which a coin, containing a first portion and a second portion made of different metals and/or metal alloys, is arranged to pass. An electrical mechanism supplies time-varying drive signals to the coil mechanism. A detection mechanism detects eddy currents induced in the coin by the coil mechanism. The coil mechanism is arranged to induce in the coin an eddy current loop, which in a predetermined region of the coin crosses a bond between the first and the second portions of the coin.

Growing community of inventors

Salisbury, United Kingdom

Geoffrey Howells