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:
Dec. 31, 1985
Filed:
Sep. 14, 1984
Craig E Nelson, Seattle, WA (US);
Marvin L Strenge, Seattle, WA (US);
TAB Leasing, Seattle, WA (US);
Abstract
An apparatus for calibrating a force measuring instrument of the type that includes a force sensitive element submerged in a liquid. The apparatus comprises a magnetic object having a known weight when submerged in the liquid, and an electromagnet. The electromagnet includes a core having a first end that extends beneath the surface of the liquid to a position near the upper surface of the force sensitive element. The electromagnet further includes a coil surrounding a portion of the core, means for energizing and deenergizing the coil, and a thermal insulator surrounding the first end of the core to prevent the core from contacting the liquid and to limit heat flow from the core into the liquid. When the coil is energized, the magnetic object is picked up from the force sensitive element and adheres to the insulator. When the electromagnet is deenergized, the magnetic object falls back onto the force sensitive element for calibration of the instrument. The means for energizing and deenergizing the coil may comprise a pulse generator for producing a high current surge of short duration to lift the weight up off of the force sensitiv e element, and a power supply for producing a lower, steady current for holding the weight against the insulator.