GB2237448A - Cleaning and lubricating retractable aerials - Google Patents

Description

A UMCE FOR CLEANING AND LUBRIECATI1tG MCTABLE AMTALS This invention

relates to retractable aerials.

Retractable aerials are widely used for 5 transmitting and receiving radio signals and the like, and whilst the present invention may be used for all forms of retractable aerials, it will be described and illustrated with special reference to car aerials.

Car aerials are normally of the retractable type in order that they may be retracted to prevent damage, for instance when the car is washed in an automatic car wash machine or by vandalism when the car is left unattended. There are two types of retractable car aerials in general use, namely a telescopic type which is extended and retracted by hand, and an automatic telescopic type in which a mast is extended/retracted by an electrical mechanism actuated normally by the on/off switch of the car radio.

The majority of car owners neglect their car aerials and consequently road dust, dirt, salt and grit build up on the aerial, and this, combined with rain and freezing conditions in winter, leads to a deterioration of the functioning of the aerial, including reduction in radio-wave reception, and jamming of the moving parts, which can ultimately lead to complete breakdown. Preferred embodiments of the present invention provide a device, which may be part of the original equipment of a car aerial as supplied, or may be later retrofitted, which device may clean the aerial and/or apply a light film of water repelling oil each time it is extended or retracted. The aerial may be kept clean and oiled thereby promoting smooth and trouble free conditions and a longer life.

According to a first aspect of the present invention, there is provided a device for cleaning and/or lubricating an aerial, the device comprising:

a body having an inlet and an outlet through which an aerial may pass; a cleaning and/or lubricating means provided on said body, the cleaning and/or -lubricating means defining a passageway through which an aerial may pass;-and a securing means for securing the device to or adjacent an aerial, such that the aerial may pass through said passageway.

Preferably, the body, said inlet and said outlet are substantially circular in cross-section and coaxial with one another. Preferably, the cleaning and/or lubricating means includes an insert of a porous resilient material contained within said body. The insert may comprise a polyurethane foam.

The cleaning and/or lubricating means may alternatively or additionally include a resilient membrane mounted in or on said body, the membrane defining an aperture for passage of an aerial, which aperture has a diameter such as to enable it to provide a wiping action when the aerial moves therethrough. The membrane may be attached to a grommet which is directly attached to and retained by the body. Preferably, a said membrane is attached to each side of the grommet. Preferably, the membrane attached to an upper side of the grommet has a smaller aperture than the aperture of the membrane attached to a lower side of the grommet. The or at least one of the membranes(s) may be protected from the atmosphere by a cap. A space may be defined between 1 W, ,C f 1 --- 1 unit.

the membrane and said cap, which space contains a hydrophobic material through which a respective aerial passes, in use. The hydrophobic material may be a foam.

Preferably, the securing means includes a collar having a base which has a circular aperture defined therein for passage of an aerial, the base also having a circumferentially disposed sidewall extending perpendicularly therefrom. wherein the sidewall and body are provided with respective parts which co-operate in order to secure said body to said cap. The body may be secured to said collar by means of a screw fit. Alternatively, said body may be secured to said collar by means of a push-fit.

Preferably, means are provided for securing said collar to an aerial assembly or to the body of a vehicle.

Preferably, the device is a substantially sealed Preferably, the body is made of a rigid material such as a non-rusting metal or a plastics material. The insert may be made from a fibrous material, for example staple f ibres, or, as mentioned, it may be made f ron a 25 foam material such as polyurethane foam. It is preferably stable to and capable of retaining a lubricating oil. The insert may be provided with a small bore which defines a passageway coaxial with the cylinder to enable the aerial to pass through it readily, the bore being of such size that the insert makes positive contact with the aerial in order to lubricate it. Alternatively, a cross-slot may be f ormed in the insert to def ine a passageway f or the aerial. The membrane is preferably constructed from a thin, tough elastomeric material, such as neoprene (for example), and the securing means for attaching the device 1 adjacent the aerial may be of any suitable form. Preferably it provides a water tight seal between the device and the car/aerial.

In use, when the aerial is extended or retracted the membrane may remove dirt which adheres to it, and the oil retained by the insert lubricates moving parts of the aerial.

To further illustrate the present invention, one particular embodiment of a device suitable for use with a retractable car aerial will now be described, by way of example, with reference to the accompanying drawings, in which:

is Figure 1 is a longitudinal sectional view of the device; Figure 2 is a sectional view along the line A-A of Fig. 1; Figure 3 is a detailed view of a part of a cleaning device in use; and Figure 4 illustrates a cap for a modified version of the device Referring to the drawing,:the device f or cleaning and/or lubricating a retractable car aerial comprises a cylindrical housing 1 having a cylindrical bore coaxial with the cylinder. two transverse open ends 2 and 3, an internal flange 4 and an external flange 5. The housing contains a cylindrical insert 6 of reticulated polyurethane foam. The insert 6 has a crossslit 20 (Figure 2) extending coaxially with the cylinder.

This cross-slit 20 allows a narrow passageway to be ( 1 4 formed along the length of the insert when an aerial is pushed through the centre of the slit. As an alternative, the insert 6 may have a narrow bore of a slightly less diameter than the car aerial.

The lower end of the housing 3 has a means 8 for attachment to thefixed, non-retractable part of the aerial.-It comprises a resilient collar having an orifice 11 and a recess 12 which snapengages the external flange 5 on the housing 1. At the upper end 2 of the housing 1 there is provided a washer 9 made from an elastomeric material such as neoprene. which provides a resilient membrane and is adhered to a grommet 10 which is retained by the housing 1 by means of the internal f lange 4. The washer 9 has a small circular orifice 21 of smaller diameter than that of the aerial.

This particular embodiment of the present invention may be installed as a retrofit in the following manner. The existing mounting nut of the aerial is removed, the attachment collar 8 is placed over the threaded outer casing, non-retractable part of the aerial, and the mounting nut is replaced and firmly tightened. The insert is impregnated with a suitable oil, placed inside the cylinder of the housing 1, and the housing snapped into place on the collar 8.

The device may operate as follows. From an extended state an aerial 22 (Fig. 3) is retracted. The aerial 22 passes through the orifice 21 and abuts against the elastomeric material of the washer 9 as it squeezes therethrough. Frictional contact between the moving retracting aerial and the washer 9 causes dirt to be removed from the aerial before it passes through the orifice. It will be appreciated that the size of the orif ice 21 and the material from which the washer 9 is ( 1 made should be selected so as to provide suf f icient frictional contact to cause removal of dirt from the aerial whilst allowing the aerial to pass re latively smoothly through the orifice. As the orifice will expand/contract as the aerial passes therethrough, it will be appreciated that material from which the washer 9 is made should be tough and durable.

During retraction, the aerial will pass through the cross-slit 20 where it will be surrounded by the insert impregnated with oil. A layer of oil will therefore be transferred to the aerial. In its fully retracted position, the top of the aerial will usually be at or adjacent the bottom of the insert 6, at the level of the aerial mounting nut.

is During extension of the aerial, the top of the aerial is pushed through the insert 6 and orifice 21, and oil is transferred from the insert 6 to the aerial. As the washer 9 exerts a resilient force upon the aerial,it tends to hold back the lower sections of the aerial, until the upper sections have been extended. Thus, if a typical aerial has five sections 1 (top) to 5 (bottom), the sections will tend to be extended in the correct order 1-2-3-4-5, whereas, without the device 1, the sections would normally extend in any order, depending upon how well cleaned and/or lubricated -the individual sections were.

Since the aerial will extend in the correct order 1-2-3-4-5, all sections will be cleaned and/or lubricated as they pass through the aperture 21. In this regard, the aerial itself will transfer oil from the insert 6 to the washer 9, and only a small amount of oil on the washer 9 may lubricate the aerial as it passes through the aperture 21.

( 1 In a variant, the grommet 10 may have two washers such as 9 adhered one to each face of the grommet. The lower washer may have an aperture in the range, for example, 2 to 6 mm (e. g. 4 mm), and the upper washer an aperture in the range, for example, 1 to 3 mm (e. g. 2 um). Then the lower washer would tend to hold back the aerial sections, and wipe off excess lubricant, as the aerial was extended.

Alternatively or additionally, a lower washer or membrane such as 9 may be provided at the lower end of or inbetween the ends of, the insert 6.

The particular embodiment described above may be modified as follows. Any suitable membrane may be provided in place of the washer (s) 9. The washer 9 may be protected from the atmosphere by a domed flexible rubber cap having a configuration similar to that of the attachment collar 8 except that the orif ice is of smaller diameter. The space between the domed cap and the washer may be f illed with a closed cell f oan which is hydrophobic to prevent the entry of water. The foam will of course have a passageway through it to allow the retractable aerial to pass through it f or example, a cross-slit such as the cross-slit 20.

An example of such an arrangement is illustrated in Figure 4. where a domed cap 30 og-resilient material is formed with a first, larger recess 31, a second, smaller recess 32 and an aperture 33. The first recess 31 has an annular groove 34 to snap-engage an external flange such as 5 on the housing 1. In this variant, the recess 31 provides a continuation of the bore within the suitably modified housing 1, to receive the insert 6. The second recess 32 receives the closed cell hydrophobic foam. The aperture 33 receives a grommet such as 10 with ( 1 one or more washers such as 9 - or a washer such as 9 is directly bonded to the cap 30. - for example on the shoulder 36 defined above the aperture 33. A lower washer such as 9 may be disposed below the second recess 32 for example, it may be bonded to the shoulder 35 defined between the recesses 31 and 32.

The collar 8 and/or the domed flexible rubber cap may be screw-threadedly attachable to a suitably adapted housing 1. This may facilitate dismantlin4.and.re- assembly of the device, for the maintenance and/or replacement of parts. The collar 8 may then be of a substantially rigid material - for example, similar to that of the housing 1.

is The collar 8 may have a central aperture of a diameter of the order of 10 to 20 mm. Preferably the diameter is in the range 14 to 16 mm.

Means may be provided for replenishing the insert with oil. For example a hole may be provided in the housing 1, the hole in turn being provided with, for example, a one-way valve so that oil may be injected into the insert 6.

25. It will be appreciated that the device may be of any suitable size in order to f it a particular size of aerial. The housing may be a cylinder'of diameter in the range 0.02 to 0.04 m. preferably of 0.03 m. The cylinder may have a length in the range 0.01 to 0.04 m, preferably of 0.03 m. - The device is constructed so as to be a substantially sealed unit so that water and dirt etc. cannot enter the housing.

C c ( 1 X -g- As an alternative to the aforementioned embodiment, a device may be provided which hais only a cleaning means such as the washer 9 as disclosed herein. As a further alternative a device may be provided having only the insert 6 as the cleaning and/or lubricating 5 means.

The above described embodiments of the invention may be modified to form an integral part of an antenna, rather than a retro-fit accessory.

At the present time, electric car aerials usually collapse approximately in the order 1-2-3-4-5 (in the above example of a five stage aerial). Thus, the upper stages may be collapsed before they can engage the cleaning/lubricating device. Therefore, it is preferred that the aerial mechanism be adapted to ensure collapsing in the order (for example) 5-43-2-1, to ensure that all sections are cleaned, as the aerial-is collapsed, as well as when it is extended. The aerial mechanism may also be adpated to ensure that, apart from the effect of any washer such as 9, as mentioned above, the aerial always extends in the order 1-2-3-4- 5. Of course, the five-stage aerial is given here only as an example, the principal applying to aerials of other numbers of stages.

In other variants, means may be provided for attaching the housing 1 (or collar 8) directly to the body of a vehicle,, rather than to an aerial. For example, the underface of the housing 1 or collar 8 may be provided with a self-adhesive material which, in use, adheres firmly to the bodywork of a vehicle, around an existing aerial, so that the aerial may pass through the device, to be cleaned and/or lubricated as, for example, described above.

The readerOs attention is directed to all papers and documents which are filed concurrently 'with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in thi s specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where -at- least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

X 0 Z 1. A device for cleaning and/or lubricating an aerial, the device comprising:

a body having an inlet and an outlet through which -an aerial may pass; a cleaning and/or lubricating means provided in or on said body, the'cleaning and/or lubricating means defining a passageway through which an aerial may pass; and a securing means for securing the device to or adjacent an aerial, such that the aerial may pass through said passageway.

Claims (1)

1. 2. A device according to Claim 1, wherein the body, said inlet and said

   outlet are substantially circular in cross-section and coaxial with one another.

   3. A device according to any of the preceding claims, wherein the cleaning and/or lubricating means includes an insert of a porous resilient material contained within said body.

   4. A device according to Claim 3. wherein the insert comprises a polyurethane foam.

   5. A device according to any of the preceding claims, wherein the cleaning and/or lubricating means includes a resilient membrane mounted in or on said body, the membrane defining an aperture for passage of an aerial, which aperture has a diameter such as to enable it to provide a wiping action when the aerial moves therethrough.

   t_ 6. A device according to Claim 5, wherein the membrane is attached to a grommet which is directly attached to and retained by the body.

   7. A device according to Claim 6, wherein a said membrane is attached to each side of the grommet.

   8. A device according to Claim 7, wherein the membrane attached to an upper side of the grommet has a smaller aperture than the aperture of the membrane attached to a lower side of the grommet.

   9. A device according to any of Claims 5 to 8, wherein the or at least one of the membrane (s) is protected from the atmosphere by a cap.

   10. A device according to Claim 9, wherein a space is defined between the said membrane or said at least one cap, which space contains hydrophobic material through which a respective aerial passes, in use of the device..

   11. A device according to any of the preceding claims, wherein the securing means includes a collar having a base which has a circular aperture def ined therein for passage of an aerial, the base also having a circumferentially disposed sidewall extending perpendicularly therefrom, wherein the sidewall and body are provided with respective parts which cooperate in order to secure said body to said collar.

   12. A device according to Claim 11, wherein said body is secured to said collar by means of a screw fit.

   13. A device according to Claim 11. wherein said body is secured to said collar by means of a push-fit.

   A j t A 14. A device according to any of Claims 11 to 13 wherein means is provided for securing said collar to an aerial assembly or to the body of a vehicle.

   15. A device according to any of the preceding claims, wherein the device is a substantially sealed unit.

   16. A retractable aerial whenever fitted with a cleaning and/or lubricating device according to any of 10 the preceding claims.

   17. A device substantially as hereinbefore described with reference to the accompanying drawi-ngs.

   Published 1991 at 7be Patent Office. State House. 66/71 High Holborn. London WC I R 47P. Further copies my be obtained from -..- - -I-- ".I126.4-f Cl--- TC"x- Newnnrt- NPI 7HZ. Printed bv Multiplex techniques ltd. St Mary Cmy. Kent.