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:
Jun. 13, 2000
Filed:
Apr. 08, 1998
Thomas R VanZandt, Redondo Beach, CA (US);
Stephen J Manion, Altadena, CA (US);
Other;
Abstract
The invention converts a conventional velocity geophone to a force-balance accelerometer. A single, spring supported geophone coil, in conjunction with a permanent magnet assembly fixed to the geophone housing, is used as both an electromagnetic velocity sensor and a force actuator. An electronic circuit is used to implement a force-balance feedback control system. The electromotive force associated with the velocity of the coil is detected and used as an input to the feedback control system. The output of the control system is applied to the same coil in such a manner as to provide negative feedback. In the presence of accelerations, the coil velocity with respect to the geophone housing is reduced essentially to zero. Thus, the force related to the external acceleration acting on the coil-mass, is balanced by the applied force. Specifically, the current applied by the control system to the same coil is proportional to the acceleration of the housing.