Automotive mobile telephone antenna silencer

• US 5,751,251 A
• Filed: 03/20/1996
• Issued: 05/12/1998
• Est. Priority Date: 03/20/1996
• Status: Expired due to Fees

• Current Assignee: Ronald M. Hutchinson
• Original Assignee: Ronald M. Hutchinson
• Inventors: Hutchinson, Ronald M.
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US08/619,849
• Time in Patent Office: 783 Days
• Field of Search: 343/722, 343/713, 343/715, 343/872, 343/873, 343/895, 343/749, 343/900, 343/901
• US Class Current: 343/715
• CPC Class Codes: H01Q 1/005 Damping of vibrations; Means for reducing wind-induced forces
• CPC Class Codes: H01Q 1/32 Adaptation for use in or on road or rail vehicles
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

A closed cell foam tubular muff encircles the helical coil portion of an automobile cellular phone antenna, the muff has a slanted top surface and reduces pressure differentials around the coil. The streamlined muff thereby reduces wind-induced whistling of the antenna. An alternative device is a solid cylindrical foam insert with a plurality of depressions formed therein which engages within the coil of the antenna. Both devices not only reduce the pressure effects which lead to whistling, but also, because of their foam composition, contribute to a damping of any randomly occurring vibrations.

Claims

1. A device for attachment to a mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights, the device comprising a cylindrical resilient foam body, wherein the foam body insertably engaged with the helical coil of the antenna and is deformed by the coil in a friction fit to fix the body to the helical coil and thereby block air flow through the coil.

2. The device of claim 1 further comprising portions of the body which define an axial bore, and wherein the helical coil is received within the axial bore.

3. The device of claim 2 wherein the helical coil of the antenna has a first external diameter, and wherein the axial bore has an inner diameter which is approximately 80 percent of the first external diameter.

4. The device of claim 2 wherein the helical coil of the antenna has a first length, and wherein the length of the body is approximately 110 percent of the first length.

5. The device of claim 1 further comprising portions of the body which define an outer cylindrical surface, and portions of the body define a plurality of grooves recessed below the outer cylindrical surface, each groove being positioned to engage with a flight of the helical coil, the body being disposed within the antenna helical coil.

6. The device of claim 5 wherein the helical coil of the antenna has a first external diameter, and wherein the outer cylindrical surface of the body has a diameter which is approximately equal to the first external diameter.

7. The device of claim 5 wherein the helical coil of the antenna has a first length, and wherein the length of the body is approximately 110 percent of the first length.

8. A device for attachment to a mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights, the device comprising a cylindrical resilient foam body, wherein the foam body engages with the helical coil of the antenna in a friction fit to fix the body to the helical coil and thereby block air flow through the coil, wherein portions of the body define an axial bore, and wherein the helical coil is received within the axial bore, and wherein portions of the body define a frustoconical top surface, and portions of the body define a frustoconical bottom surface, the top surface and the bottom surface serving to direct relative winds around the helical coil of the antenna.

9. A device for attachment to a mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights, the device comprising:

a cylindrical resilient foam body, wherein the foam body engages with the helical coil of the antenna in a friction fit to fix the body to the helical coil and thereby block air flow through the coil;

portions of the body which define an outer cylindrical surface; and

portions of the body which define a plurality of grooves recessed below the outer cylindrical surface, each groove being positioned to engage with a flight of the helical coil, the body being disposed within the antenna helical coil;

wherein portions of the body define a conical top surface, and portions of the body define a conical bottom surface below the top surface, the top surface and the bottom surface serving to direct relative winds around the helical coil of the antenna.

10. The device of claim 9 wherein the inclination of the conical surfaces is approximately 30 degrees.

11. A mobile telephone antenna assembly comprising:

a) a mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights, the coil having a first diameter; and

b) a cylindrical resilient foam body, wherein the foam body has portions defining an interior bore which has a diameter which is less than the first diameter of the antenna coil, the foam body being insertably engaged with the helical coil of the antenna in a friction fit to deform the body and thereby fix the body to the helical coil and thereby block air flow through the coil.

12. The assembly of claim 11 wherein the helical coil of the antenna has a first external diameter, and wherein the axial bore has an inner diameter which is approximately 80 percent of the first external diameter.

13. The assembly of claim 11 wherein the helical coil of the antenna has a first length, and wherein the length of the body is approximately 110 percent of the first length.

14. The assembly of claim 11 further comprising portions of the body which define an outer cylindrical surface, and portions of the body define a plurality of grooves recessed below the outer cylindrical surface, and the body is disposed within the antenna helical coil such that each groove engages with a flight of the helical coil.

15. A mobile telephone antenna assembly comprising:

a) a mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights;

b) cylindrical resilient foam body which is engaged with the helical coil of the antenna in a friction fit to fix the body to the helical coil and thereby block air flow through the coil, wherein portions of the body define an axial bore, and wherein the helical coil extends through the axial bore;

c) portions of the body which define a frustoconical top surface, and

d) portions of the body defining a frustoconical bottom surface, the inclinations of the frustoconical surfaces being about 45 degrees, and the top surface and the bottom surface serving to direct relative winds around the helical coil of the antenna.

16. A mobile telephone antenna assembly comprising:

a) mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights;

b) a cylindrical resilient foam body which is engaged with the helical coil of the antenna in a friction fit to fix the body to the helical coil and thereby block air flow through the coil;

c) portions of the body which define an outer cylindrical surface;

d) portions of the body which define a plurality of grooves recessed below the outer cylindrical surface, wherein the body is disposed within the antenna helical coil such that each groove engages with a flight of the helical coil; and

e) wherein portions of the body define a conical top surface, and portions of the body define a conical bottom surface below the top surface, the top surface and the bottom surface serving to direct relative winds around the helical coil of the antenna.

17. A device for attachment to a mobile telephone antenna having a straight portion and a helical coil formed of a plurality of coil flights the device serving as an accessory for retrofitting an antenna which is evidencing unpleasant whistling, the device comprising:

a) a cylindrical body formed of a resilient closed cell foam material, being insertable within the helical coil flights; and

b) portions of the body which define a cylindrical outer surface, wherein the helical coil has a first internal diameter, and the cylindrical outer surface has an external diameter which is greater than the first internal diameter; and

c) portions of the body which define a plurality of grooves which are recessed below the cylindrical outer surface, the grooves being positioned to engage with individual coil flights when the body is deformed to pass within the helical coil and is disposed in a friction fit within the helical coil of the antenna, the body thereby blocking air flow through the coil.