GB2097596A - Television aerials - Google Patents

Abstract

A television aerial has a boom 12 mounted on a post 11 projecting from a base 10, the boom being formed from two mouldings 17,18, (Figures 2,3, not shown), within which are respective electrical conducting members extending along the length of the boom, elements 13 passing through sockets in the mouldings and having their inner ends connected to the conducting members respectively and at least some of the elements 13 being snap engaged in their sockets to hold the two mouldings together. <IMAGE>

Description

SPECIFICATION Television aerials This invention relates to aerials for receiving television signals over a range of frequencies and being of small size so as to be suitble for indoor use. Such aerials are usually referred to as set top aerials although of course they are not necessarily to be placed on the television set itself.

A set top aerial of the kind with which the invention is concerned has a base from which projects a post, at the top of which is carried a boom.

Set top aerials are usually of two kinds namely one in which the boom carries a dipole of loop form, a reflector and a number of elements and the other, with which the invention is concerned, has no dipole or reflector but has elements only. This type of aerial is called a log periodic aerial.

The boom has a number of spaced projecting elements, of length and spacing to enable signals of a range of frequencies to be picked up. The signals are led from the elements to two connecting members, which in turn are connected to the television set through a flexible cable, which is usually the coaxial type.

The object of the invention is to provide a set top television aerial of log periodic type which is inexpensive to produce and has not separate fasteners in its construction and which has high performance characteristics.

According to the invention there is provided a television aerial comprising a base, a post projecting from the base and carrying a boom, the boom being formed from a pair of mouldings each having formations to receive an electrically conducting member extending lengthwise of the boom, and the two such members having provision at one end for external electrical connection to said conducting members, each moulding having sockets for respective elements to extend laterally of the boom at spaced positions along it and the elements having, at their inner ends, formations to enable them to be electrically connected to the respective lengthwise conducting members and at least some of the elements carried in one of the mouldings being arranged to snap engage in guides in the other of the mouldings, to secure the mouldings together.

The invention will now be described by way of example with reference to the accompanying drawings in which; Figure 1 is a perspective view of a television aerial constructed in accordance with the invention, Figure 2 is a side elevation view of one of the mouldings making up the boom of the aerial, Figure 3 is a view of the other side of the other of the mouldings, Figure 4 is a plan view of one of the elements, Figure 5 is a side elevation view of the element, Figure 6 is a plan view of a connector within the boom, Figure 7 is an end elevation view of the connector, Figure 8 is an enlarged cross-sectional view of the boom on the line 8-8 in Figure 2 shown before assembly and; Figure 9 is a side elevation view of the base of the aerial.

Referring to Figure 1 this shows the complete aerial which is of the log periodic type. It includes a base 10 from which projects an upwardly extending post 11. At the top of the post is supported a boom 12 which is substantially horizontal in use and from this projects a number of straight elements 13. As seen in Figure 1 the elements are of varying length being longer at one end than the other of the boom and they are spaced apart lengthwise of the boom as well as occupying two parallel planes. At one end the boom has an outlet connection to a flexible coaxial cable 14. This in use is connected to the input socket of the television set with which the aerial is to be used.

The post 11 is adjustably mounted on the base 10 in a manner which will be described in relation to Figure 9. At its upper end the post 11 is divided into two arms 15, 16 which snap engage with the boom 12, which is of square cross-section. The base 10, posts 11 and boom 12 are made from plastics material and thus the arms 15, 16 have sufficient resilience to enable the boom to be snapped into place as shown. Furthemore the boom can be rotated through 90" within the arms 15,16 thus providing adjustment for optimum signal reception.

Figures 2 and 3 and Figure 8 show the two mouldings 17, 18 from which the boom 12 is made up. The mouldings are similar but of opposite hand, being generally L shaped in section. At one end of each is part of a guide 19,21 which embraces the cable 14. Covering this and serving to assist in holding the mouldings together in a sleeve 22 shown in Figure 1. At its other end one of the mouldings 17 has a square integral end cap 23 which is the assembled boom closes the end thereof.

Each boom moulding has an internal wall or partition 24, 25. Between this and the wall, which is parallel to it, are a number of sockets defined by pairs of stepped projections 26. Alternate ones of these pairs of projections 26 have internal stepped members 27. One of the projections at one end of the boom is lengthened to provide an end stop projection 28. Between the wall 24 or 25 and the adjacent pairs of projections 26 is located a flat metal strip 29, 31.

In the two oppositely directed faces of the two mouldings 17, there are part circular sleeves formed integrally with the moulding. These occupy two parallel planes and the sleeves alternate between the two planes along the length of the boom, as can be clearly seen in Figure 1 and also in Figure 3. Into each socket formed by a pair of projections 26 and the adjacent flat metal strip 29, or 31, the elements 13 are fitted. As seen in Figures 4, 5 each element is a circular cross-section metal wire having at one end a flattened or spade shaped portion 32.

As seen in Figure 5 this is offset from the axis of the element 13 itself. As can be seen from Figure 8 the elements 13 fit into the sockets in tight engagement with the flat metal strip 29 or 31. Alternate sockets have the internal lugs 27 which assist in such tight engagement with the flat metal strips 29 or 31 so that good electrical connection can be made between the elements and such flat metal strip. The other alternating elements 13 pass through holes in the surface carrying the guide sleeves of part circular section.

Such guides sleeves are of two sorts identified at 33 and 34 respectively. The guide sleeves 33 align with the round hole in the moulding and receive elements 13 which are passed from the direction of the metal strip 29 or 31 and into the respective holes. The other guide sleeves 34 are close to the edges of the mouldings and the corresponding elements 13 are located in the closed ended sockets containing the lugs 27.

As seen in Figure 8 it is possible to fit the two mouldings together so that they make up a square cross-section and they are held together by lateral snapping together of the elements 13 into the respective guide sleeves 34. Such snap engagement occurs at spaced positions along the length of the boom so that the mouldings which make up the boom are firmly held together substantially throughout their lengths. The snap engagement occurs with elements held in the manner described on both the mouldings simultaneously.

At the end of the boom at which the cable 14 emerges is a connector member 35 of plate like form, as shown in Figures 6 and 7. At one end this has a semi cylindrical portion 36 flanked by two small pegs 37. This defines a half circular recess at one side of the plate and a half circular projection at the other. In the centre of the plate and projecting in opposite directions respectively are integral split posts 38,39. The coaxial cable 14 is of the kind having an inner conducting core which is surrounded by insulation. This is surrounded by metal braiding forming an outer conductor and this in turn is encased in further insulation. The cable end enters the recess and the inner conducting core projects and is slotted into the post 38 on the same side of the member 35 as the recess.The braiding is passed through a hole 40 in the member 35 and is then passed across the other side of the member and is slotted into the other of the posts 39. This assembly is inserted into the space between the two exposed ends of the metal strips 29,31 which have respective holes to accept the posts 38 and 39 on the connector member 35. The walls 24,25 are relieved in this zone to make provision for the connector member 35. By this means electrical connection is made to the two metal strips 29, 31. To accept the ends of the posts 38, 39 there are integral circular section sockets, one of which is shown in Figure 2 at 41.

By this means an extremely simple but effective boom is formed which is snapped together in the manner described and does not therefore require any additional fastenings to keep the two mouldings together.

Figure 9 shows the base 10 and the post 11. The base is generally wedge shaped in side elevation having four corner feet as shown. A socket formation 42 near one end accepts the post 11. In the side walls of this socket formation are holes to accept short journals 43 attached to the lower end of the post 11.

The arrangement is such that the journals can be snapped into the holes 42 but cannot easily be removed therefrom. The lower end of the post 11 is split to aid in the snap engagement of the journals in the holes 42. In the side walls of the socket formation 41 are triple recess detent formations 44. The post 11 carries a pair of lateral pegs 45 which can engage in these formations 44 alternatively. Three alternative positions for the post 11 relatively to the base 10 are shown in Figure 9. There is sufficient resilience in the assembly to allow the post to be moved between the positions shown and by this means the angular position of the boom can be adjusted relatively to a flat surface on which the base is standing. Adjustment of the boom is therefore permitted, by this post adjustment relatively to the base, in a plane coinciding with the length of the boom.

It is to be understood that other forms of base with or without any form of adjustment of the post relatively to the base can be used in conjunction with the boom described.

Claims (10)

1. Atelevision aerial comprising a base, a post projecting from the base and carrying a boom, the boom being formed from a pair of mouldings each having formations to receive an electrically conducting member extending lengthwise of the boom, and the two such members having provision at one end for external electrical connection to said conducting members, each moulding having sockets for respective elements to extend laterally of the boom at spaced positions along it and the elements having, at their inner ends, formations to enable them to be electrically connected to the respective lengthwise conducting members and at least some of the elements carried in one of the mouldings being arranged to snap engage in guides in the other of the mouldings, to secure the mouldings together.

2. Atelevision aerial as claimed in claim 1 wherein each moulding is provided with means for locating the respective conducting member, and the elements engage in sockets with their end formations arranged in tight engagement with the conducting member.

3. Atelevision aerial as claimed in claim 2 in which the mouldings have the sockets to accept element end formations arranged in rows which, in the two mouldings are offset from one another, so that the elements extend from both sides of the boom in staggered rows.

4. Atelevision aerial as claimed in claim 3 wherein alternate elements at each side of the boom snap engage in their respective guides.

5. Atelevision aerial as claimed in claim 4 wherein the elements which snap into their guides, at each side of the boom are spaced along the length of the boom, so that the mouldings are held together substantially along the whole length of the boom.

6. A television aerial as claimed in any one of the preceding claims wherein electrical connection to the conducting members is arranged at one end of the boom, at which an insulating plate is provided to separate the electrical connections to the respective ends of the conducting members.

7. Atelevision aerial as claimed in any one of the preceding claims wherein the boom is of square section and has the elements extending from two opposite sides, the boom being mounted on the post in a manner permitting adjustment about the boom longitudinal axis.

8. Atelevision aerial as claimed in claim 7 in which the post has resilient arms at its upper end at least partly to encompass and grip the boom and whereby the boom can be adjusted about its longitudinal axis or removed from the post.

9. Atelevision aerial as claimed in any one of the preceding claims wherein the post is adjustably mounted on the base for movement in a plane coinciding with the length of the boom.

10. Atelevision aerial substantially as hereinbefore described with reference to and as shown in the accompanying drawings.