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:
Sep. 15, 1981
Filed:
Dec. 26, 1979
Edward R Basham, Fort Worth, TX (US);
L Max Mosely, Arlington, TX (US);
Gearhart Industries, Inc., Fort Worth, TX (US);
Abstract
Improvement in free point indicators disclosed in U.S. Pat. No. 3,690,163. Discloses new strain sensing system having all electrical/electronic components, other than coil and diode components, located at earth's surface remote from high temperatures and shock loading. Includes a toroidal armature within the downhole tool having coils or windings to generate a pulsating magnetic flux field developed by an alternating current. A U-shaped permanent magnet is disposed such that a portion of its constant magnetic flux field occupies physical space common with a portion of the pulsating magnetic flux field for mutual influence. A diode provided in series with each winding limits electrical current passing through each winding to pulsating DC. The constant flux of the magnet and the pulsating flux of the coils are relatively positioned in opposing sense whereby the current passing through each winding is of designated magnitude. Any relative movement between the magnet and the toroidal armature results in change of net current flow which is measured at the earth's surface as a DC voltage. The preferred embodiment utilizes two windings symetrically wound around the armature. However, the invention can be successfully utilized with only one winding.