Communications: radio wave antennas – Antennas – With vehicle
Reexamination Certificate
2001-12-13
2003-04-01
Ho, Tan (Department: 2821)
Communications: radio wave antennas
Antennas
With vehicle
C343S900000, C343S711000
Reexamination Certificate
active
06542127
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to automotive antenna assemblies and installations and, in particular, to a boot for an antenna assembly.
Commercial frequency radio broadcasts began in the 1920s and, as the popularity of broadcast radio increased, automobile manufacturers began to offer radios as optional equipment. Eventually, radios were made a part of many vehicles' standard equipment. Indeed, in the present day it is difficult to purchase an automobile without a radio. Antennas, which are used to receive the radio frequency broadcasts and convey the signals to the radio, are well known.
Prior art automotive fixed antennas are typically part of an antenna assembly including an antenna mast that is mounted in an aperture in a surface of an automobile body. A housing extends through the aperture and receives a center conductor having a threaded stud attached thereto. An antenna mast nut is attached at a lower end of the antenna mast. The antenna mast nut attaches to the threaded stud, electrically connecting the center conductor to the antenna mast and to a coaxial cable that extends to the radio. An isolator, which functions as an insulator for the antenna mast and central conductor and which is typically constructed of polypropylene or similar material, is injection molded between the housing and the antenna mast and center conductor. When the automobile is in motion or at other times such as during automatic car washes, the antenna mast of the prior art antenna assemblies is subjected to extremely high but known side forces. These side forces induce a resultant compression force that is applied to the polypropylene isolator. Eventually, the polypropylene material of the isolator of the prior art antenna assemblies may fatigue, allowing water to penetrate deep into the housing. The water causes corrosion of the coaxial cable connections, resulting in reduced reception and the eventual failure of the antenna. The automobile manufacturer, the owner of the automatic car wash facility, or the consumer must then replace the antenna. Regardless of who bears the cost, replacement is undesirable because an antenna subjected to known forces should not have to be replaced.
It is an object of the invention, therefore, to provide a boot for an antenna assembly that will advantageously absorb compressive forces without failing while simultaneously acting as a gasket for sealing the internal connections of the antenna from exterior air and water leakage.
SUMMARY OF THE INVENTION
The present invention solves the problems with automotive antenna assemblies noted above by providing a boot, preferably constructed of neoprene, rubber, or similar material, as part of an automotive antenna assembly.
The antenna assembly includes an elongated antenna mast that is mounted in an aperture in an upper surface of an automobile body. A preferably zinc, generally tubular die cast housing extends through the aperture above the upper surface of the automobile body and receives a cylindrical center conductor that is connected to a coaxial cable extending from a radio. One end of the center conductor extends upwardly through the housing and includes a threaded stud formed thereon. The antenna mast is attached to the threaded stud of the center conductor by an antenna mast nut. The center conductor is thus electrically connected at one end to the antenna mast and at another end to a coaxial cable that extends to the radio. An isolator, typically constructed of polypropylene or similar electrically nonconductive material, is injection molded between the zinc housing and the antenna mast and center conductor.
The boot includes a generally disk-shaped base portion having a cylindrical projection extending from an upper surface thereof. The boot is preferably constructed of neoprene or other similar material. The base portion includes a cylindrical recess having a first diameter formed in a bottom surface. The projection includes a cylindrical bore extending through an upper surface thereof having a second diameter that is less than the first diameter. The boot is advantageously disposed along an upper surface of the isolator of the prior art. The bore is connected to the recess in the base portion, forming a common cavity through which the center conductor may pass and be held securely in place. The recess in the base portion is preferably formed to have a close interference fit with the outer surface of the housing, while the bore is preferably sized to have a close interference fit with the outer surface of the central conductor. A plurality of ribs preferably extends from an upper portion of the inner surface of the bore and from a lower portion of the inner surface of the recess. The ribs advantageously augment the sealing of the outer surfaces of the central conductor and the housing to which the boot is attached.
In addition, the ribs and the material of the boot aid in sealing the surfaces to prevent water leakage past the center conductor to the coaxial cable connections. By preventing the water leakage the boot of the present invention extends the effective life of the antenna.
REFERENCES:
patent: 4360814 (1982-11-01), Wells
patent: 4625213 (1986-11-01), Horn
patent: 5838281 (1998-11-01), Blaese
patent: 6366249 (2002-04-01), Jones et al.
Close Richard A.
Cross Robert D
Grossman Vitaly
General Motors Corporation
Hargitt Laura C.
Ho Tan
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