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. 13, 1991
Filed:
Oct. 31, 1988
Hartmut Schmid, North Vancouver, CA;
Leif R Mannerstrom, North Vancouver, CA;
Glenayre Electronics Ltd., Vancouver, CA;
Abstract
A temperature-compensated tuning screw (22) for use with a cavity filter (20) is provided. The tuning screw (22) has an elongate body (36) with a longitudinal bore (38). A compensating member (40) is positioned at least partially within the bore (38). At least one compensation bimetallic washer (44) deflects with decreasing temperature and causes the compensating member (40) to protrude further from the body (36). The compensation bimetallic washers (44) become flatter with increasing temperature and a coil spring (42) causes the compensating member (40) to be partially retracted into the bore (38). The movement of the compensating member (40) causes an overall length, L, of the tuning screw (22) to change. The tuning screw (22) can be screwed into a hole (32) in a cavity filter (20) so that the tuning screw (22) penetrates the cavity filter (20) a distance, P. A temperature-induced change in L, .DELTA.L, causes a change in P, .DELTA.P. The change in penetration, .DELTA.P, compensates for temperature-induced changes in the geometry of the cavity filter (20) and substantially corrects for a temperature-induced frequency drift, .DELTA.f'.