AU5537598A - Retractable antenna - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT 99 9. 9 *9* .9 *9 9 9 9* .9 i e 9 9 9 .9 9e 99* 9 .9 o ft Applicant: ROBERT LENES MATTHEWS Invention Title: RETRACTABLE ANTENNA The following statement is a full description of this invention, including the best method of performing it known to me: TITLE OF THE INVENTION: Retractable Antenna FIELD OF THE INVENTION: This invention relates to a rod of selected stiffness and flexibility which may be extended or retracted and stored in a relatively small space.

BACKGROUND OF THE INVENTION: It is convenient to extend and retract antennas particularly for use with vehicles. One way is to use telescopic antennas made, for example, from tubular metal sections, which can be collapsed to occupy a small space. It is also possible to use solid metal rods which can be extended from. for example, a cabin pillar in a motor vehicle, but cannot be collapsed into a small space.

Both of these latter solutions suffer from the difficulty that the telescopic rod or the solid rod are likely to deform permanently upon collision with an obstacle preventing the antenna from retracting.

The invention described below provides a solution to these problems.

9* p BRIEF SUMMARY OF THE INVENTION: This invention provides a rod of selected stiffness and flexibility which may be extended or retracted and stored in a relatively small space, wherein the dimensions of the rod and the material or materials from which it is made are so selected that: the bending radius as measured by the survivable bend has a bend diameter to antenna diameter ratio of from 80 to 120 together with inherent built-in memory to allow the rod to return to the original straight position when released.

BRIEF DESCRIPTION OF THE DRAWINGS: The accompanying drawings illustrate two embodiments of the invention in which: Figure 1 is a side view of a retracted antenna in a housing; Figure 2 repeats the side view of Figure 1 but shows the retracted antenna in a housing inside that structure of a caradjacent-its boot; and Figures 3A and 3B are side-views (perpendicular to each other) illustrating motorised erecting and retracting units for use with the antennas of Figures 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION: The word "rod" as used in this specification refers to elongated objects of various cross-sections including round, square and rectangular.

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Preferably, the tensile strength of the rod at three standard deviations below the mean exceeds 1200 MPa when tested according to modified ASTM D 3916.

Preferably, the tensile modulus at three standard deviations below the mean exceeds GPa when tested according to ASTM D 3916.

Preferably, the elongation at break is less than 3%.

Preferably, mounting shear splintering does not progress further than 30mm on a standard mounting shear splintering apparatus.

The rod should have inherent memory to return to its approximate straight position when fully extended.

The material or materials from which the rod is made may be metallic, non-metallic or a combination of both. For example, the metallic material may be of metal or metal coated with chromium or may be of metal fibres. The non-metallic material may be carbon fibre, carbon mesh or carbon powder. Non-conducting fibre, such as glass fibre, may be used to form a foundation or core for the rod. Pultrusion may be used in the-construction of the non-metallic rod or metal fibres. Conductive particles, such as metal particles, may be used to improve conductivity.

It is necessary to balance flexure and stiffness of the rod to ensure that the rod can maintain its memory to return to its original shape and be inserted into a space or tunnel having a selected shape.

The functioning of the antenna and the names of the various associated parts are apparent S: from the accompanying drawings. The pulleys shown in Figure 3 can be driven by an electric motor to erect and retract the rod.

It has been found that rods according to the invention provide reduced wind noise.

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The antenna housing and rod can be installed to any suitable location on a motor vehicle .i including the front or rear fenders and/or boot.

9 .Since the rods according to the invention may be retracted into a small space, the antenna length may be extended to provide further reception range.

Claims (8)

1. A rod of selected stiffness and flexibility which may be extended or retracted and stored in a relatively small space, wherein the dimensions of the rod and the material or materials from which it is made are so selected that: the bending radius as measured by the survivable bend has a bend diameter to antenna diameter ratio of from 80 to 120 together with inherent built-in memory to allow the rod to return to the original straight position when released.

2. A rod as claimed in Claim 1, wherein the rod is *.6"aformed from a metal material.

3. A rod as claimed in Claim 1, wherein the rod is 15 formed from a non-metallic material.

4. A rod as claimed in Claim 1, wherein the rod is formed from a combination of metallic and non-metallic materials.

5. A rod as claimed in Claim 2 or 4, wherein the metallic material is metal coated chromium or metal fibres.

6. A rod as claimed in Claim 3 or 4, wherein the non-metallic material is carbon fibre, carbon mesh, carbon powder or glass fibre.

7. A retractable antenna incorporating a rod as claimed in any one of Claims 1 to 6.

8. A retractable antenna substantially as hereinbefore described with reference to the accompanying drawings. Dated this 17th day of FEBRUARY 1998 ROBERT LENES MATTHEWS By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent Attorneys of Australia \\MELBOl\home$\Leanne\Keep\pn8194.doc 18/02/98