GB2120856A

GB2120856A - Antenna assembly

Info

Publication number: GB2120856A
Application number: GB08213671A
Authority: GB
Inventors: David John Sidney Westwood; Michael Bishop Williams
Original assignee: Thorn Emi Ferguson Ltd
Current assignee: Thomson Multimedia Sales UK Ltd
Priority date: 1982-05-11
Filing date: 1982-05-11
Publication date: 1983-12-07
Also published as: GB2120856B

Abstract

In an antenna assembly a dish 2 is attached to a support by means 5 including two rings 7 and 9 which are capable of relative rotation by pins 10 on ring 9 moving in arcuate slots in ring 7. Three arms 12,13 are pivotably connected to a member 14 on the dish and are attached to the ring 9, the arm 13 being of adjustable length to tilt the dish. The ring 7 and hence the dish is pivotable about an axis on member 4 on a support post 3 by an adjustable arm 6. <IMAGE>

Description

SPECIFICATION Antenna assembly The present invention relates to an antenna assembly and especially, but not exclusively, to one for receiving television signals transmitted via geostationary satellites.

The present invention provides an antenna assembly comprising an antenna dish attached to a support by mounting means such that, in use, the dish is capable of moving between two predetermined orientations in a substantially direct path with a sweep whose plane is inclined to the longitudinal axis of the support, said movement being effected by a single operation on one element of the mounting means.

Clearly, the dish is also capable of movement in the plane parallel to the longitudinal axis of the support.

Preferably the antenna assembly comprises an antenna dish attached to a support by mounting means such that, in use, the dish is capable of moving between two predetermined orientations in a substantially direct path with a sweep whose plane is inclined to the longitudinal axis of the support, said movement being effected by a single pivoting action of the dish on one element of the mounting means.

Thus the dish of an antenna assembly of the present invention may be moved readily and simply between two predetermined orientations each chosen to correspond to a position of substantially maximum reception of a signal e.g. a television signal transmitted via a geostationary satellite. The antenna assembly may receive signals from one or morefurthersources providing that the corresponding orientation for that source is on the path traced out by the dish intermediate the two predetermined orientations; in this case the assembly has means to retain and/or locate the dish in this intermediate orientation when desired. The two predetermined orientations need not be at the two extremes of travel of the dish.

The dish may be moved along the path between the two orientations automatically (e.g. driven mechanically or electrically) and can be controlled at or adjacent the assembly or remotely therefrom; alternatively it can be manually moved.

The mounting means may comprise a first member for fixing to a support, a second member capbale of engaging with, while being movable relative to, said first member and means to lock the two members together. Preferably the second member includes a surface which is slidable over a surface of complementary shape on the first member to effect the relative movement between the members.

In particular embodiment of the invention the first member has a flat surface with at least one arcuate slot, the second member has a flat surface to abut and to slide over that of the first member and the second member has a projection to extend from its flat surface for engagement in the arcuate slot and to lock the members together when required. The second member may have two (or more) arms extending from the flat surface, one (or more than one) arm forming a pivot connection with the dish and the other arm having means for longitudinal extension, being connected to another portion of the dish.

Another aspect of the present invention provides for a kit of parts for an antenna assembly as herein described and claimed.

In order that the invention may more readily be understood a description is now given, by way of example only, reference being made to the accompanying drawings in which: Figure lisa side view of an antenna assembly embodying the present invention.

Figure 2 is a view from below of parts of the assembly of Figure 1, and Figure 3 is a rear view of the assembly of Figure 1.

The illustrated antenna assembly, generally designated as 1, can be readily switched from one predetermined orientation of antenna dish 2 to another, thereby enabling it to selectively receive (and so feed to a television set) television signals transmitted via either of two geostationary satellites A and B whose positions in the sky correspond to those two predetermined orientations; the orientations are not restricted to those which lie in paths whose planes are parallel to the longitudinal axis of the support (as in known assemblies), but include those whose planes are inclined to that axis. Controls for the switching from one satellite to the other are located on or adjacent the television set or on the remote control unit (preferably operable via the television set) for the set.

Antenna assembly 1, as shown in Figure 1, has a post 3 with a clamp (not shown) at its lower end for rigidly securing the assembly to a building. A bracket 4, fixed to the upper end of post 3, is pivotally connected, at its free ends, to a mounting 5 for antenna dish 2 which is maintained at a desired angle relative to post 3 by an arm 6 pivotable on mounting 5 and releasably clamped to post 3. This angle can be adjusted by varying the length of that part of arm 6 extending between post 3 and mounting 5.

Mounting 5 includes a first ring 7, which has three arcuate slots 8 (see Figure 3), and a second ring 9 with three projections 10, each of which passes through one slot 8 and has a retaining nut 11 threaded on it to thereby clamp rings 7 and 9 together. Ring 9 can be readily rotated relative to ring 7 once the nuts 11 have been unscrewed sufficiently to loosen the clamping effect.

Two rods 12 fixed to ring 9 and an arm 13 movable with respect to ring 9 are all pivotally connected to an annular lug 14 of dish 2, so that, by varying the length of arm 13 between ring 9 and lug 14, dish 2 can be swept-through an angle relative to ring 9. An electric motor 15 has a drive shaft 16 with circumferential teeth 17 engaging with a toothed rack 18 along part of the length of arm 13 to move the arm selectively in both directions through a substantially U-shaped support 19 on ring 9 and thereby to tilt dish 2 (see Figure 2).

The extent of movement of arm 13 and thereby the sweep of dish 2 (its extreme positions being indi cated by the broken lines in Figure 2) is limited by stops 20 at the ends of rack 18.

When positioning the antenna assembly 1 for use, firstly the rings 7 and 9 are set with arm 13 in a horizontal position on the side of required sweep to a second satellite, and the dish 2 is set at one of its extreme sweep positions relative to ring 9 with arm 13 fully extended (i.e. drive shaft 16 abuts one stop 20 of rack 18). Having taken a compass bearing, assembly 1 is rotated about the axis of pole 3 until dish 2 is set at an estimated value of the azimuth angle for the first satellite, A; then the arm 6 is adjusted until dish 2 has an elevation angle corresponding to that estimated for A, the dish now being at a coarse setting for A. Fine adjustment is achieved by moving the dish about this setting in order to find the position corresponding to a maximum output signal reading on a meter connected to the output of dish 2.

Then, to set the assembly, for the second satellite, B, the motor 15 is activated to move the arm 13 to its other extreme position (i.e. with the teeth 17 of shaft 16 against the other stop 20); the clamping action of rings 7 and 9 is loosened by unscrewing nuts 11 and then ring 9 and dish 2 together are rotated until a maximum output reading is obtained again on the meter. The assembly 1 is now correctly set up to receive signals from A in one extreme position of shaft 16 and rack 18 and from B in the other extreme position, switching between the satellites being readily achieved by actuating motor 15.

Antenna dish 2 can be switched to receive signals from a third satellite provided that the orientation for this satellite is on the path traced out during a sweep of dish 2. In orderto intentionally stop the motor 15 when the shaft 16 is at an intermediate position between stops 20 there may be, for example, a mechanical motor disconnector suitably positioned on rack or there may be a servo system on the shaft.

The assembly could be readily modified to halt at more than one intermediate orientation.

Claims

1. An antenna assembly comprising an antenna dish attached to a support by mounting means such that, in use, the dish is capable of moving between two predetermined orientations, in a substantially direct path with a sweep whose plane is inclined to the longitudinal axis of the support, said movement being effected by a single operation on one element of the mounting means.

2. An antenna assembly comprising an antenna dish attached to a support by mounting means such that, in use, the dish is capable of moving between two predetermined orientations in a substantial direct path with a sweep whose plane is inclined to the longitudinal axis of the support, said movement being effected by a single pivoting action of the dish on the mounting means.

3. An antenna assembly comprising an antenna dish and means to mount the dish on a support such that, in use, the dish is capable of moving between two predetermined orientations in a substantially direct path with a sweep whose plane is inclined to the longitudinal axis of the support, said movement being effected by a single pivoting action of the dish on the mounting means.

4. An assembly according to any one of the preceding claims wherein the dish has three, spaced-apart connections with the mounting means, to effect pivoting action of the dish on the mounting means, two connections fixed to the mounting means and pivoting on the dish and the other connection including means to effect variation of the spacing between portions of the dish and the mounting means.

5. An antenna assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

5. An assembly according to any one of the preceding claims, wherein the mounting means comprises a first member for fixing to a support, and a second member for connection with the dish and capable of engaging with, while being movable relative to, said first member and means to lock the two members together.

6. An assembly according to Claim 5, wherein the second member includes a surface which is slidable over a surface of complementary shape on the first member to effect the relative movement between the members.

7. An antenna assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

New claims or amendments to claims filed on 10 May1983 Superseded claims Claims 1 to 7 inclusive New or amended claims:

1. An antenna assembly comprising an antenna dish attached to a fixed support by mounting means formed of two members which can be secured together in any one of a number of relative positions, one of said members being pivotable relative to the support about two orthogonal axes and, in use, being releasably locked to the support, the other member of the mounting means being connected to the dish, the two members, in use, being secured togethersuch that the dish is capable of moving between two predetermined orientations in a substantially direct path inclined to both pivot axes, said movement being effected, in use, by a single pivoting action of the dish relative to the mounting means.

2. An antenna assembly according to claim 1, wherein one member of the mounting means includes a surface which is readily slidable over a surface of complementary shape on the other member, to enable the members to be moved between relative positions.

3. An antenna assembly according to claim 1 or claim 2, including means to secure the members of the mounting means together in any of the relative positions, the securing means also maintaining the members attached when moving the members between relative positions.

4. An assembly according to any one of the preceding claims wherein the dish has three, spaced-apart connections with the mounting means, to effect pivoting action of the dish on the mounting means, two connections fixed to the mounting means and pivoting on the dish and the other connection including means to effect variation of the spacing between portions of the dish and mounting means.