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:
Mar. 23, 1993
Filed:
Mar. 28, 1991
Neil H Akkerman, Houston, TX (US);
AVA International Corporation, Houston, TX (US);
Abstract
A fail safe valve actuator is disclosed that is powered by an electric motor. A valve stem with a helical groove is moved in one direction by a ball nut rotated by the electric motor to move a valve member to its operating position. The valve member is held in operating position by a solenoid. When power fails, a spring moves the valve stem in the other direction to move the valve member to its fail safe position. A torque limiting device protects the electric motor from the high torque created when the valve stem abruptly stops moving when the valve member reaches its operating position. A centrifugal brake absorbs a portion of the energy released when the power fails and the valve stem is moved rapidly to its fail safe position by the spring.