GB2082868A - Mountings for cathode ray tubes - Google Patents

Abstract

Lugs (20) used for mounting a cathode ray tube (11) to a housing include a first portion (21) which is shaped to conform to the surface of the tube and an integral second portion (22) for screwing or bolting the lugs to the housing. The cathode ray tube is mounted by bonding (e.g. using a resin adhesive) the first portion (21) to the surface of the tube and then securing to the housing. <IMAGE>

Description

SPECIFICATION Mountings for cathode ray tubes This invention relates to the mounting of cathode ray tubes, and particularly, although not exclusively to the mounting of the picture tube of a television receiver.

Hitherto a cathode ray tube, e.g. a television picture tube has commonly been mounted to a housing, a cabinet for example, by one of two alternative methods. In one method angled brackets are held against the glass envelope of the cathode ray tube by tensioned, metal bands which encompass the tube. The brackets are usually positioned close to the edge of the display screen so as to engage the housing to which it is secured by screws or pins. In an alternative method of construction a rigid framework is used which surrounds the cathode ray tube and is bonded, or alternatively mechanically anchored thereto at discrete locations. The framework is then secured to the housing.

Implementation of either of the abovementioned methods of construction proves to be both time consuming and expensive and, particularly when tensioned bands are used tends to impose undesirable stresses on the housing to which the tube is mounted.

It is therefore an object of this invention to provide an improved method and arrangement for mounting a cathode ray tube to a housing.

According to one aspect of the invention there is provided a method of mounting a cathode ray tube to a housing comprising the steps of: (a) providing a plurality of lugs, each comprising a first part which is shaped so that a surface thereof conforms to a respective region of the tube envelope and an integral second part, disposed relative to said first part, for engaging the housing and being secured thereto when the said first part engages the tube envelope, (b) applying a bonding agent to the said surface of each said first part and/or to the corresponding regions of the tube envelope, (c) fixing the lugs to the envelope and (d) securing the second part of each said lug to the housing.

According to another aspect of the invention there is provided a lug for mounting a cathode ray tube to a housing, comprising a first part which is shaped so that a surface thereof conforms to a region of the tube envelope, and an integral second part, disposed relative to said first part, for engaging the housing and for being secured thereto when the said first part engages the tube envelope.

In order that the invention may be more readily understood and carried into effect a particular embodiment thereof is described, by way of example only, by reference to the accompanying drawings of which, Figure 1 a shows a front elevation view of a cathode ray tube; in this example a television picture tube, Figures 1 b and 1 c respectively illustrate side and plan views of the tube, Figure 2 shows a perspective view of a mounting lug according to the present invention, Figure 3 shows the manner of bonding the lug to the cathode ray tube, and Figure 4 shows a structure produced during the manufacture of a lug.

Although the example described below relates to a mounting for a television tube it will be appreciated by a person skilled in the art, that the present invention is also applicable to other kinds of cathode ray tube.

Referring to Figure 1 the television tube includes an evacuated, glass envelope 10 comprised of a generally rectangular screen 11 and a rear, flared portion 12 joining a central, axially extending neck 13 which accommodates an electron gun assembly (not shown).

In one, known construction, the tube is mounted to a panel which forms a frame for the screen 11 and which constitutes part of a housing for the tube. The panel projects marginally beyond the periphery of the screen, the inner edge thereof being represented schematically by the dashed line L in Figure 1 a.

In accordance with this example of the invention the tube is mounted to the panel using two profiled metal, or alternatively plastics material, lugs 20 which are bonded to the tube along the curved side walls of the rear portion 1 2 which join and extend rearwardly from, the opposed relatively short edges of the screen 11.

Each lug 20 is positioned symmetrically about the central, horizontal plane of the tube envelop".

The detailed structure of a lug is shown more clearly in the perspective view of Figure 2. Each lug is of unitary construction and comprises two main parts, namely a preformed, elongate part 21 which is shaped so that is lower surface conforms to the curved side walls of the tube, as shown in Figure 1 a, and a further part 22, disposed relative to the part 21, so as to be capable of engaging the inner face of the housing panel, for mounting thereto, when the above-described shaped part is positioned against the tube.

In this example of the invention the part 21 comprises a strip which is curved so that the lower surface thereof has a generally concave profile.

The curvature of part 21, is chosen so as to substantially match that of the tube surface against which it must seat, and the part is dimensioned so as to engage the side wall of the tube envelope along a major portion of its length.

As will be appreciated, the part 21 may be differently shaped and dimensioned to suit an alternative tube construction.

Part 21 is linked to part 22 by an intervening neck region 23 and lies in a plane which is substantially perpendicular to the tangential plane which meets the upper surface 24 of the part 21 midway between its ends. The part 22 has two symmetrically disposed holes H for securing the lug to the panel.

Mounting is achieved with relative ease by applying a bonding agent, such as a resin adhesive, to the lower surface of the part 21 and/or to the corresponding portion of the tube side wall, the layer of adhesive resin being represented at R. The lug is then accurately positioned relative to the axes of the tube using a jig, so that the said lower surface is seated against tube wall, as shown in Figure 3. When both lugs have been firmiy bonded to the envelope, the tube is positioned within the housing, the part 22 being secured thereto by screws or bolts which are located by the holes H.

It has been found in practice that the abovedescribed arrangement provides considerable advantages over arrangements used hitherto.

Since the tube engaging part of each lug is shaped to conform to the surface of the envelope contact can be achieved over a relatively large surface area thereby substantially reducing the load applied to any one part of the tube wall. Furthermore the above-described lugs are relatively simple to manufacture and can be formed either by injection moulding a plastics material or alternatively may be stamped from a single sheet of metal. A stamped metal plate suitable for forming a lug of the above-described type is shown in Figure 4 and comprises two elongate portions 31 and 32 separated by a neck portion 33. The elongate portion 31 is shaped to a desired curvature suitable for engaging the wall of the cathode ray tube, and the portion 32 is folded about the relatively short narrow neck portion 33, defined by the dashed lines L1 and L2, to an extent sufficient for engaging the particular housing to which the tube is to be mounted.

The improved mounting arrangement provided by the present invention is particularly advantageous in the construction of television receivers.

Claims (8)

1. A method of a mounting a cathode ray tube to a housing comprising the steps of: (a) providing a plurality of lugs, each comprising a first part which is shaped so that a surface thereof conforms to a respective region of the tube envelope and an integral second part, disposed relative to said first part, for engaging the housing and being secured thereto when the said first part engages the tube envelope, (b) applying a bonding agent to the said surface of each said first part and/or to the corresponding regions of the tube envelope, (c) fixing the lugs to the envelope and (d) securing the second part of each said lug to the housing.

2. A method according to Claim 1 including providing two lugs.

3. A method according to Claims 1 or 2, wherein each lug is manufactured by the steps of: (a) cutting from sheet metal an integral planar plate comprising two elongate parts separated by a relatively short neck portion, (b) shaping one of said elongate parts so as to conform to a region of the tube envelope, and (c) folding the other part about the neck portion to an extent sufficient to engage the housing when the said first part engages the tube envelope.

4. A method according to Claim 1 or 2 wherein each lug is made of a plastics material and is manufactured by injection moulding.

5. A method according to Claims 1 to 4 wherein the lower surface of the first part has a concave profile.

6. A method substantially as hereinbefore described.

7. A lug for mounting a cathode ray tube to a housing comprising a first part which is shaped so that a surface thereof conforms to a region of the tube envelope and an integral second part, disposed relative to said first part, for engaging the housing and being secured thereto when the said first part engages the tube envelope.

8. A lug substantially as hereinbefore described by reference to and as illustrated in the accompanying drawings.