Robert C Blumberg, 781740 James St, Saint Paul, MN 55118

5988348, Nov 23, 1999

Jun 27, 1997

8/883780

Doug Martin - Woodinville WA
Larry Cannon - Bothell WA
Mark Waechter - Seattle WA
Rodrigo Berho - Seattle WA
Daniel Everhart - Edmonds WA
Robert Blumberg - Seattle WA
Paul Leonard - Kirkland WA
Cheryl Germany - Bellevue WA
Dan Gerrity - Bellevue WA
Alan C. Phillips - Los Altos CA
Stuart K. Neubarth - Mountain View CA

Coinstar, Inc. - Bellevue WA

G07D 508

194317

A coin discrimination apparatus and method is provided. Coins, preferably after cleaning, e. g. using a trommel, are singulated by a coin pickup assembly configured to reduce jamming. A coin rail assists in providing separation between coins as they travel past a sensor. The sensor provides an oscillating electromagnetic field generated on a single sensing core. The oscillating electromagnetic field is composed of one or more frequency components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various frequencies are fixed, and the interaction of each frequency component with the coin can be accurately determined without the need for complicated electrical filters. In one embodiment, a sensor having a core, preferably ferrite, which is curved, such as in a U-shape or in the shape of a section of a torus, and defining a gap, is provided with a wire winding for excitation and/or detection.