The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 08, 1978
Filed:
Sep. 20, 1976
Ludwig Braum, Laufen, DE;
Libandor Trading Corporation Inc., Monrovia, LR;
Abstract
A method of, and apparatus for, checking coins, wherein the coin to be checked is moved through a constantly regulated alternating-current field of a measuring coil. The influence of the coin upon the alternating-current field produces a regulation magnitude formed from the difference between a reference voltage and the rectified oscillator-measuring voltage. The regulation magnitude readjusts, by means of the oscillator circuit, the oscillator-measuring voltage at the measuring coil to a constant value. During coin checking the regulation magnitude is employed as the coin checking criterion in a manner such that it is possible to determine by means of an evaluation circuit whether this regulation magnitude has reached a value falling within an upper and lower boundary. The time-constant of the regulation circuit is chosen such that slow changes can be controlled, but the oscillator-measuring voltage is also maintained constant during relatively rapid passage of the coin through the measuring coil and there is obtained as high as possible amplitude of the regulation magnitude.