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. 02, 1982
Filed:
Nov. 19, 1980
Applicant:
Inventor:
Akira Yamamura, Framingham, MA (US);
Assignee:
Ferrofluidics Corporation, Nashua, NH (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16J / ;
U.S. Cl.
CPC ...
277-1 ; 277 80 ; 277135 ;
Abstract
A ferrofluid rotary-shaft seal apparatus of extended seal life, particularly adapted for use as an exclusion seal with a computer-disc-drive spindle, which seal apparatus comprises: an annular permanent magnet; first and second pole pieces, one end of which pole pieces extends into a close, noncontacting relationship with the surface of the rotary shaft to form a gap therebetween; ferrofluid in the gap to form at least one O-ring seal; and a heat-conductive sheet material in a close, heat-conducting relationship with at least one pole piece, to aid in removing heat from the ferrofluid in the gap, thereby extending the seal-apparatus life in use.