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:
Jan. 16, 1979
Filed:
May. 24, 1977
Eugene C Heltemes, White Bear Lake, MN (US);
Minnesota Mining and Manufacturing Company, Saint Paul, MN (US);
Abstract
An improved apparatus for producing a magnetic field within an interrogation zone for detecting perturbations in the field produced by the presence of a ferromagnetic marker element includes at least a pair of field producing coils, each of which is substantially planar and is positioned on opposite sides of the interrogation zone such that the planes of the coils are parallel to each other and to a corridor defined therebetween. Each of the coils are of substantially the same overall dimension and have either a 'figure-8' or 'hour-glass' shape, each half of which is symmetric about a horizontal axis passing through a crossing or necked-in portion and consist of a substantially triangular shape.