GB2332782A

GB2332782A - Antenna mount

Info

Publication number: GB2332782A
Application number: GB9727252A
Authority: GB
Inventors: Michael John Mcalinden
Original assignee: Northern Telecom Ltd
Current assignee: Nortel Networks Ltd
Priority date: 1997-12-23
Filing date: 1997-12-23
Publication date: 1999-06-30
Also published as: GB9727252D0

Abstract

An antenna mount comprises a clip 83, 84, 85, 86 for holding an antenna 81. The clip is mounted on top of a hemisphere 53 with a bolt 52 through the bottom of it. The bolt and nut 54 attaches the clip to a support 41 which is attached to a mounting pole. The antenna can be oriented with the nut loose; the nut is then tightened to lock the antenna into place. The clip may be replaced by a protective shield (101, figure 7) onto which the antenna is bolted.

Description

AN ANTENNA MOUNTING SYSTEM FIELD OF THE INVENTION The present invention relates to mounting apparatus and in particular an apparatus for mounting and orientating an antenna.

BACKGROUND TO THE INVENTION Radio communication systems are currently employed for various types of communications, from television broadcasts via satellites to local telecommunication networks. In the case of a TV satellite receiver a typical system comprises a satellite dish, an antenna and a decoding means. The antenna receives the signal and provides a further signal by wire to a decoding means. In the case of wireless local loop or fixed wireless access telecommunications, subscribers are connected to a telecommunications network by a radio link in place of the more traditional method of copper cable. The radio transceivers at the subscriber's premises communicate with a base station, which provides cellular coverage over, typically, a 5km radius in urban environments.

A significant cost in providing a subscriber with an antenna lies in the cost of affixing the antenna to the subscriber's property, orienting it towards a suitable basestation, and maintaining the antenna in situ: cost of individual fixings, cost to the operator of maintaining stock of many different kinds of fixings for different installation circumstances, and cost of employing installers to physically install and maintain the apparatus.

In addition, the task of physically installing and maintaining the antenna and their fixings is typically conducted high up on the subscriber's buildings, reached using a ladder. This brings with it safety problems: the worker typically requires both hands to hold and fit the apparatus to the building, leaving him with no free hand with which to steady himself as he works. Even if a secure mobile plafform is provided, difficulties will be encountered especially, for instance, in windy conditions.

Difficulties in installation also arise where the fixings are such that the task of installing the components involve the installer, for example, tightening nuts which are out of view on the far side of the assembly. This increases the likelihood of components being dropped, with its attendant safety hazard to anyone below, and can further increase installation time.

A further disadvantage of existing systems is that different joints in the assembly employ distinct sizes, shapes, or even forms of fixing. This requires the worker either to carry several different tools with which to install the system, or to carry one tool at a time, but make several trips up and down the ladder, adding to the time and cost of installation.

Different climatic or geographic circumstances give rise to different physical protection needs for an antenna in service: in tropical regions antennas must be protected from direct solar heating; in Australia plastic housings are susceptible to attack by birds; in other places, daily thermostatic cycling may be around 30 c.

OBJECT TO THE INVENTION The present invention seeks to provide an improved apparatus for mounting antennas.

SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided an orientatable mounting arrangement for mounting and orientation of an antenna, the arrangement comprising: support means capable of supporting and securing an antenna and comprising an hemispherical surface and fixing means; a mounting means connected to or forming part of a mounting member, the mounting means comprising a hemispherical surface complimentary to that of the support means such that said support means is receivable and orientatable within the mounting means and wherein the orientation of said support means is fixed upon application of said fixing means.

Advantageously the fixing means is a bolt means passing through an aperture in the hemispherical surface of the support means, and a complimentary screw means within the mounting means. Advantageously the aperture has a diameter larger than that of the shank of the bolt means such that the support means is orientatable in both elevation and azimuth with respect to the mounting means. Alternatively the bolt means may be formed integrally with the hemispherical surface of the support means.

Advantageously the mounting arrangement further comprises a protective shield for an antenna, the shield being secured to the support means.

The mounting member may be a mounting clamp capable of being secured to a mounting pole for example. Altematively, the mounting member may be a mounting bracket.

According to a further aspect of the present invention there is provided an orientatable support means for use in an orientatable mounting arrangement for mounting and orientation of an antenna, the support means comprising a hemispherical surface for engagement with a complimentary surface on a mounting means; and fixing means for fixing the support means with respect to the mounting means.

Advantageously the fixing means is a bolt means passing through an aperture in the hemispherical surface and capable of being received by a complimentary screw means within a mounting means. Advantageously the aperture has a diameter larger than that of the shank of the bolt means such that the support means may be orientated in both elevation and azimuth with respect to the mounting means. Alternatively the bolt means may be formed integrally with the hemispherical surface of the support means.

Advantageously the orientatable support means further comprises a protective shield for an antenna, the shield being secured to the support means.

BRIEF DESCRIPTION OF THE DRAWINGS In order to show how the invention may be carried into effect, embodiments of the invention are now described below by way of example only and with reference to the accompanying figures in which: Figure 1(a) shows a typical antenna installation site on a rooftop; Figure 1 (b) shows a pole assembly adapted to be fixed to a wall.

Figure (2) shows an antenna attached to the top of a pole with a mounting clamp of the present invention; Figure (3) iliustrates construction and installation of a preferred mounting clamp of the present invention; Figures 4(a), 4(b), and 4(c) show plan and cross-sectional views of a preferred mounting clamp of the present invention; Figures 5(a) and 5(b) show plan and cross-sectional views of the clamp shown in figure 4 with an orientatable antenna support Figure 6(a), 6(b), 6(c) and 6(d) show in detail orientatable antenna supports for use with the mounting clamp of the present invention; Figure 7 shows a cross-sectional view of a separable protective shield for an antenna.

DETAILED DESCRIPTION OF INVENTION Many buildings are equipped with a mounting pole, mounted at or about roof-top level and upon which, for example, a television antenna is mounted. Such poles are typically circular in cross section, hollow, and arranged substantially vertically although other variations are possible.

However, the precise diameter of circular poles for example may vary between locations: typical diameters of circular cross section poles include, but are not limited to, 40mm, 50mm, and 60 mm. Specific size ranges may also vary between geographic regions.

Where a new FWA (fixed wireless access) antenna for example is to be installed and such a pole is already in place on a subscriber's building, it is often convenient to mount the FWA antenna on the existing pole. Figure 1(a) shows such a mounting pole (1) mounted on the apex of a roof and upon which an antenna (2) has been mounted; Figure 1(b) shows an antenna (2) fixed to a mounting pole (1) equipped with two brackets (3) by which the pole may be attached to a wall.

Figure 2 shows a mounting clamp (21) in accordance with the present invention. The mounting clamp is easily attached to such a pole (1); it is also removable. The figure shows the clamp (21) in position on a pole (1) and supporting an antenna (2).

Referring now to Figures 2 and 3, the clamp (21) comprises a pair of jaws (31) means for drawing the jaws together for example in the form of a threaded bolt (32) and a corresponding nut (22), and mounting means (33) for securing the antenna (2). The jaws (31) include a plurality of complimentary channels which together define a plurality of sockets (34a, 34b, 34c), which receive poles (la, 1b, 1c) of different cross-sections; pole cross-sections may differ both in shape and size. The clamp is arranged to be fitted to a pole by lowering the clamp over the upper end of the pole so as to engage the pole in an appropriately sized socket (34a, 34b or 34c), and then sliding the clamp down and around the pole to the desired height and orientation. The means for drawing the jaws together (22,32) are then operated to close the jaws (31) around the pole such that the clamp is firmly held in place by the pressure exerted by the clamp on the surface of the pole. While the means for drawing the jaws together has been described as comprising a threaded bolt (32) and corresponding nut (22), other means could be employed for example a clip or clamp arrangement. The mounting means (33) is designed to accept and retain in place an antenna arrangement (2).

In the arrangement just described, the clamp will typically be constructed from a resilient material such that the jaws (31) are naturally disposed slightly ajar. This allows the clamp to be easily fitted over a pole prior to drawing the jaws together and also allows the clamp to be easily removed from the pole by unscrewing the bolt (32) and nut (22) such that the jaws again rest slightly ajar.

Alternatively, the jaws (31) may be pivoted (for example hinged) with respect to each other to provide the necessary movement to permit opening and closing. In this embodiment the jaws will be manually opened upon unscrewing the bolt (32) and nut (22) to loosen and remove the clamp from the pole.

The mounting clamp may be adapted to accommodate regional variation in pole sizes. For example in Australia, where many buildings have poles of diameter 21 mum, 38mm, or 50mm already affixed to them at or near rooftop level, a mounting clamp could be specifically adapted to fit each of those three sizes of pole. Figures 2, 3, 4, and 5 each illustrate examples of clamps in accordance with the present invention adapted to fit three sizes of circular cross-section pole.

Alternatively or in addition the clamp may be adapted to accommodate a range of pole sizes within each socket (34a, 34b, 34c) by, for example, manufacture of the jaws (31) and means for drawing the jaws together (32, 22) such that there is sufficient movement between the jaws to allow a range of pole sizes or shapes within each socket.

As a further alternative, where a pre-installed pole is found to be of a nonstandard size, then a flexible, resilient pad may be employed to reduce the effective diameter of a socket to provide a good fit. Advantageously, such a pad may be self-adhesive on one face to facilitate application either to an inward-facing wall of the socket, or to the pole itself.

Advantageously, the provision of a single clamp fixture to fit multiple pole sizes permits a reduction in the stock which must be held by installers, both in the warehouse and in the vehicles used by the installation workers.

Only a single kind of stock item need be carried instead of one per pole size, leading to a reduction both in the likelihood of an installer in the field running out of a specific fixture size and, consequently, in the resultant cost of retuming to base to collect the required part.

In a further embodiment shown in Figures 4 and 5, the mounting clamp also comprises a lip (41), or other means by which the clamp is retained at or near the top of the pole during installation prior to drawing the jaws together. The lip (41) extends along the edges of the jaws of the top of the clamp and is arranged so as, in operation, to protrude over the polereceiving sockets. As the clamp is engaged over the upper end of a pole (1) during installation, the lip (41) abuts against the upper rim (51) of the pole, thereby preventing the clamp from passing further down the pole.

The lip is designed to take the weight of the clamp once in place on the pole, prior to the clamp being tightened into place. This embodiment is designed primarily for locating antennas at or near an end of a pole.

Whilst Figures 4 and 5 show a lip extending continuously along the upper edge of the jaws (31), a separate, lip may be provided for each polereceiving socket. Nor need such a lip extend around the complete edge of a socket. Each such lip should be capable in operation of supporting the clamp at the top of a pole. The lip may also be displaced above or below the upper face of the jaws, thereby allowing the clamp to be affixed at differing distances from the end of the mounting pole.

The presence of the lip (41) on the clamp both improves installer safety and reduces installation time. The clamp may be placed, single handed, upon the top of the mounting pole and is retained there by gravity while the worker orients the clamp, potentially using only one hand, and tightens the fixing, again potentially using only one hand, so as to secure the clamp in place. Similarly, replacement and removal of the clamp may be effected potentially using one hand only. This consistently leaves the installer with a free hand to steady himself safely in position during the installation process.

Whilst the embodiments described above refer to clamps adapted to fit vertical oriented poles, the present invention is also applicable where clamps are for attachment to poles in other orientations, as would be apparent to a person skilled in the art.

The jaws (31) and mounting means (33) of the clamp (21) may be formed as a single casting in a resilient material: aluminium or a durable resilient plastics for example. The precise choice of material may vary according, among other things, to the durability and installability characteristics required: for example, aluminium is more durable than many plastics, but plastics may be both lighter and cheaper to produce.

The opposing surfaces of the jaws may be textured, to give improved grip on a pole: for example, in the case of sand-cast aluminium, the natural texture may provide sufficient grip.

The jaws may also be formed from a single sheet of resilient material (for example lightweight, corrosion-resistant metal) bent to shape. In such an embodiment, contact with the pole may typically be achieved only near the upper and lower faces of the clamp.

The means for drawing the jaws together is, ideally, adapted to be retained across the jaws prior to installation on the pole. Where the tightening means is provided by a nut (22) and bolt (32), these may be inserted and retained in position at manufacture, or at least prior to delivery to the installation site.

Preferably, the bolt (22) is a coach bolt with a square-section grip with a correspondingly shaped aperture in the jaws to accept it. This arrangement prevents rotation of the bolt while the nut is tightened or loosened, thereby further enabling single-handed installation and removal.

The use of a pre-fitted nut (22) and bolt (32) will reduce the number of operations to be performed at the point of installation, thereby reducing installation costs. Such a feature will reduce the likelihood of any part of the jaw drawing means (31, 32) being dropped during installation, thereby improving the safety of installation engineers.

The mounting means (33) is preferably adapted to receive an antenna base, whilst also allowing easy orientation of an antenna towards a suitable receiver and/or transmitter. The antenna base may be either part of an antenna assembly itself or a separate support means or component which acts to support the antenna (2).

Referring to figures 4 and 5 the preferred mounting means (33) in the clamp comprises a part spherical or hemispherical surface (42) which is adapted to receive a corresponding complementary surface (53) associated with a separate support means or the base of an antenna assembly. An aperture (43) is provided through which a mounting bolt (52) may be passed to fix the support means with respect to the clamp.

During installation, the bolt (52) protruding from the spherical surface of the support means is lowered into the aperture (43) in the clamp, thereby retaining the support means in position on the clamp mounting means by gravity, prior to tightening the bolt and a corresponding fixing nut (54).

The arrangement is particularly stable where the mass of the antenna support is balanced around the axis of the bolt. Once again a coach bolt is preferred as the mounting bolt since it again facilitates safe and effective single-handed installation and removal, whilst permitting full orientation of the support means until the bolt and fixing nut (54) are tightened to fix the orientation.

The bolt (52) may pass through an aperture in the spherical surface of the support means and the diameter of the shank of the bolt may be smaller than that of this aperture such that the support means may be orientated to some degree in both elevation and azimuth with respect to the clamp mounting means (33).

Altematively the bolt may be integrally formed with the support means or its shank may be complimentarily sized to an aperture in the hemispherical surface of the support means, and the aperture of the hemispherical surface of the mounting means may be oversized with respect to the shank to allow a degree of orientation in both elevation and azimuth.

Figure 6 shows an orientatable antenna support means capable of mating with the clamp mounting means (33). Figure 6(a) shows a sectional view and Figure 6(b) a partial rear elevation view of the orientatable support means adapted to retain an antenna (81). The orientatable support preferably comprises a base-plate (85), a backplate (84), a ball fixing (53) comprising a bolt (52) and capable of mating with the clamp mounting means (33). The support further comprises lugs (83) on the upper face of the base-plate (85). The antenna shown now as (81) is supported on the base-plate (85). Conveniently, the orientatable support is manufactured from spring steel, although it is possible to employ plastics materials with reinforcing means for stressed access such as the hooks (86) which hook over an upper surface of the antenna (81) thereby exerting a downward and forward pressure on the antenna so as to retain it on the base-plate.

Lateral movement of the antenna relative to the support is prevented by one or more lugs (83) extending upwards from the baseplate (85) into complementary sockets in the base of the antenna.

Figure 6(c) shows a perspective view of the orientatable support. The antenna is inserted by locating it under the hooks (86) and pushing the antenna home over the lugs (83), during which process the back-plate (84) is temporarily deformed. Removal of the antenna is by the reverse process.

Figure 6(d) shows an altemative clip fastening means by which an antenna might be retained to an orientatable support means. In this example, the support comprises a socket (87) and the antenna comprises a complementary plug (88), the plug and socket being provided with releasable co-operating latching means - in this example in the form of a resilient tongue (80) on the plug and a corresponding aperture (89) on the socket - which in operation retain the plug in the socket.

Other means could also be utilised to releasably retain the antenna on the support, as would be apparent to a person ordinarily skilled in the art.

The preferred orientatable support means is adapted to rest on the clamp mounting means (33) and to be retained there by gravity during its initial orientation. Tightening the locking nut (54) onto the downward-facing bolt (52) or vice versa locks the support in the chosen orientation.

This arrangement again improves safety during installation by permitting substantially one-handed installation. Furthermore, the provision of a downward orientation of the fixing bolt will obviate difficulties as are known to arise with existing antenna mounting systems in which fastenings must, from time to time, be adjusted on the side of the mounting facing away from the installer; in the present arrangement, the single bolt can be unfastened both easily and simply.

Separation of the orientatable support from the antenna itself also permits simplification both in production and in installation: replacement of an antenna in the field, either for repair or upgrade, is made easier and may be faster since the antenna to be replaced may be rapidly removed from the support and a new antenna inserted without the need to re-orient the assembly towards the basestation. Furthermore, the equipment replacement cost is reduced since the antenna and the support may be replaced separately.

During installation of an antenna arrangement, the orientatable support may be placed in position on the clamp mounting means (33) and loosely retained in position by affixing the locking nut (54) and bolt. Electronic apparatus adapted to determine the best orientation of the plafform for signal reception from and transmission to a local basestation may then be temporarily mounted on the platform - ideally in the position to be occupied ultimately by the antenna itself - and the support oriented until a suitable orientation is established. The support may then be locked in that orientation by tightening the locking nut (54) and bolt. The electronic apparatus may then be removed and the antenna attached rigidly to the support, thereby taking up the orientation determined by the removed electronic apparatus.

Subsequent replacement of an antenna in the field, either for repair or upgrade, is made easier and may be faster since the antenna to be replaced may be rapidly removed from the support and a new antenna inserted without the need to re-orient the assembly towards the basestation. Furthermore, the equipment replacement cost is reduced since the antenna and the support may be replaced separately.

While the support means has been described as cooperating with the mounting means of a clamp (21), the support means could also be used with suitable mounting means on other mounting members such as a wall mounted bracket for example.

Referring now to Figure 7, a separable protective shield (101) attaches to, or comprises, an orientatable support. In the example shown, the orientatable support comprises a hemispherical surface (53) and bolt (52) to engage a complementary nut (54) and optional washer (107). The shield is designed to protect faces, other than the front, of the antenna, which may itself comprise a front protective shield (102) and a body (103) comprising the essential electronic components. The nature of the protection required to be provided by the separable protective shield (101) is determined by the environmental conditions at the point of installation.

Weather protection may be provided against excessive heating from direct sunshine, whilst protection against bird attack may, for example, be provided by a substantially metal shield. The shield may also be adapted to afford protection against electromagnetic interference.

The antenna body (103) is provided with simple fastening means to attach the antenna to the shield (101): in the example illustrated, the antenna body (103) comprises a bolt (104) retained in position in the body and which passes through an aperture (105) in the shield. A single nut (106) may then be attached to retain the antenna in position within the shield.

Other attachment means may be employed, for example clip-fastening means.

Separation of the protective shield from the antenna itself permits simplification both in production and in installation: replacement of an antenna in the field, either for repair or upgrade, is made faster since the antenna to be replaced may be rapidly removed from the shield and a new antenna inserted without the need to re-orient the entire assembly towards the basestation. Furthermore, the equipment replacement cost is reduced since the antenna and the protective shield may be replaced separately.

The protective shield may be adapted to suit local requirements: for example, reflective shields provide thermal protection from direct sunshine in tropical areas or other weather protection; metal protective shields provide greater physical protection from bird attack (it is known, for example, for birds to attack and destroy plastics protective shields in Australia). Where a separable orientatable support is not required, the antenna arrangement may comprise an integral protective shield.

In a preferred embodiment of the present invention, similar fixings (for example similar-section bolts and complementary nuts or wing-nuts) are employed for each component of the mounting system, especially where components of the fastenings are separable from the assembly. This means that the worker installing or maintaining the fixings needs only a single-size wrench or other appropriate tool to tighten or loosen such fixings. It also simplifies the worker's task in that, if all such nuts required may be placed in a pouch or pocket prior to starting work, any one removed will fit that part of the fixing currently being worked upon. This reduces the weight of equipment to be carried to the point of installation, and reduces installation time.

Claims

CLAIMS 1. An orientatable mounting arrangement for mounting and orientation of an antenna, the arrangement comprising: support means capable of supporting and securing an antenna and comprising an hemispherical surface and fixing means; a mounting means connected to or forming part of a mounting member, the mounting means comprising a hemispherical surface complimentary to that of the support means such that said support means is receivable and orientatable on the mounting means and wherein the orientation of said support means is fixed upon application of said fixing means.
2. An orientatable mounting arrangement according to claim 1 wherein the fixing means is a bolt means passing through an aperture in the hemispherical surface of the support means, and a complimentary screw means within the mounting means.
3. An orientatable mounting arrangement according to claim 2 wherein the aperture has a diameter larger than that of the shank of the bolt means such that the support means is orientatable in both elevation and azimuth with respect to the mounting means.
4. An orientatable mounting arrangement according to claim 1 further comprising a protective shield for an antenna, the shield being secured to the support means.
5. An orientatable mounting arrangement according to claim 1 wherein the mounting member is a mounting clamp capable of being secured to a mounting pole.
6. An orientatable mounting arrangement according to claim 1 wherein the mounting member is a mounting bracket.
7. An orientatable support means for use in an orientatable mounting arrangement for mounting and orientation of an antenna, the support means comprising a hemispherical surface for engagement with a complimentary surface on a mounting means; and fixing means for fixing the support means with respect to the mounting means.
8. An orientatable support means according to claim 7 wherein the fixing means is a bolt means passing through an aperture in the hemispherical surface and capable of being received by a complimentary screw means within a mounting means.
9. An orientatable support means according to claim 8 wherein the aperture has a diameter larger than that of the shank of the bolt means such that the support means may be orientated in both elevation and azimuth with respect to the mounting means.
10. An orientatable support means according to claim 7 further comprising a protective shield for an antenna, the shield being secured to the support means.
11. An orientatable support means according to claim 7 wherein the support means further comprises a base plate, a back plate extending from the base plate and having one or more hook elements, and one or more lugs extending from the base plate, which together are adapted to secure an antenna to the support means.
12. An antenna arrangement having an orientatable support means comprising a hemispherical surface for engagement with a complimentary surface on a mounting means; and fixing means for fixing the support means with respect to the mounting means.