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:
Nov. 27, 1984
Filed:
Jan. 30, 1984
James P Corbett, Santa Barbara, CA (US);
Other;
Abstract
A force and pressure transducer comprises a plate-like crystal. Two separate portions of the crystal are maintained in oscillation at separate frequencies by a circuit. The force to be measured, is applied by a seating to a part of the crystal edge such that compression in one of the oscillating portions causes the frequency of that oscillating portion to change substantially whereas the frequency of the other portion changes only minimally. In the past it has been difficult to manufacture crystals in which the frequency versus temperature response of each of the two oscillating portions was sufficiently well matched to permit the difference frequency between the portions to be used as the instrument output signal. This invention resides in the application of a second fixed force by a spring via a seating to a second part of the crystal edge in such a way as to influence the frequency of oscillation of this second portion. In so doing the second seating can be adjusted to cause the frequency change due to temperature of the second oscillating portion to become as nearly as possible matched to the frequency versus temperature response of the first oscillating portion of the crystal thus providing a frequency change derived by computing the difference frequency between the two portions. This difference frequency forms the instrument output and responds only to the force applied to the instrument and not to the ambient temperature of the instrument.