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. 08, 1983
Filed:
Jul. 20, 1981
Robert L Jones, La Habra, CA (US);
NDT Instruments, Inc., Huntington Beach, CA (US);
Abstract
A bolt elongation measurement apparatus and method for measuring the length of bolts of all sizes and shapes. The apparatus utilizes a microprocessor-based digital system including a binary counter which counts pulses generated by a high frequency oscillator during the time interval between the entry into the bolt of a first pulse and exit from the bolt of a second pulse derived from the reflection return of ultrasonic energy from the opposite end of the bolt. The count is applied to a computer for calculation of bolt length or of bolt stretch due to mechanical stress. The calculation also incorporates data input via thumbwheel switches and corresponding to material velocity, stress correction factor, measurement temperature, and thermal correction factor. A unique digital filtering algorithm ensures an accurate and stable measurement. The receiver of the apparatus overcomes the problem of spurious ultrasonic reflection characteristics of threaded bolts by means of a dual characteristic echo sensing circuit to deal with stress-induced pulse distortion and a unique gain contour circuit to deal with spurious echo pulses that are characteristic of threaded bolts.