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:
Aug. 10, 1976
Filed:
Jun. 27, 1975
Paul D Engdahl, Costa Mesa, CA (US);
Other;
Abstract
A three-axis instrument for recording peak accelerations in earthquakes and like kinds of shocks. Recording is by scratches made by hard styli on small metal record plates. No power source and no maintenance are required. The seismic recording elements have novel configurations of mass, spring, and lever arm which permit improved combinations of sensitivity and natural frequency for any given magnitude of stylus friction. For example, a sensitivity of 0.25 cm per g with a natural frequency of 32 Hz may be attained, where error due to a stylus frictional force of 70 mg is less than 1 percent of full-scale. Both hydraulic and magnetic dampers are employed. The latter also provide motional electrical signals for use in calibration.