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. 06, 1990
Filed:
Apr. 10, 1989
John M Sewell, Baltimore, MD (US);
William F Werner, Severn, MD (US);
Martin Marietta Corporation, Bethesda, MD (US);
Abstract
A low frequency sound producer including a plurality of magnetostrictive vibrators arranged seriatim end to end to define a ring. Each vibrator unit includes a plurality of laterally related magnetostrictive rods which, in the illustrated embodiment, are formed of rare earth magnetostrictive material. Structure is provided for compressively prestressing the rods. The prestressing structure includes permanent magnets for providing a permanent magnetic bias in the rods. Coils are magnetically coupled to the rods for causing the desired magnetostriction thereof corresponding to an input AC signal applied to the coils. Opposite ends of the individual vibrator units define facial abutments in defining the continuous ring configuration. In the illustrated embodiment, the ring configuration is polygonal and the facial abutment surfaces at the ends of the units define a 60.degree. included angle. The entire sound producer is provided with an outward enclosure of synthetic resin whereby each vibrator unit defines an enclosed water-sealed assembly.