公开(公告)号：US3576244A

公开(公告)日：1971-04-27

申请号：US3576244D

申请日：1969-01-08

Applicant: VENDO CO

Inventor： PTACEK JAMES F ,  CESSNA JOHN E JR

IPC: G07D5/08 ,  G07F3/02

CPC classification number: G07D5/08

Abstract: A coin acceptor that detects the bulk resistivity and permeability of a coin and determines whether or not the coin is valid. A two-coil inductor forms one arm of a normally unbalanced Maxwell bridge and is disposed at a test station which is interposed in a channel through which the coin passes. The two coils have series aiding magnetic fields and are disposed on opposite sides of the coin channel with the lines of force crossing the channel at generally right angles to the opposed faces of a coin under test. A valid coin moving through the lines of force causes the inductance to change and effect balancing of the bridge. If this occurs throughout a predetermined test period, a coin deflector below the test station is withdrawn to permit the coin to enter an accept path.