US3462634A

US3462634A - Apparatus and method for supporting filamentary heaters in an electron gun assembly

Info

Publication number: US3462634A
Application number: US602308A
Authority: US
Inventors: Horst H Blumenberg
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1966-12-16
Filing date: 1966-12-16
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19

Description

g 1969 H. H. BLUMENBERG 3,

APPARATUS AND METHOD FOR SUPPORTING FILAMENTARY HEATERS IN AN ELECTRON GUN ASSEMBLY Filed Dec. 16, 1966 FiGI I2 IO 76 5 320 'FIGZ 62 2 FIGS INVENTOR HORST H. BLUMENBERG ATTORNEYS United States Patent US. Cl. 313-271 11 Claims ABSTRACT OF THE DISCLOSURE A support assembly which uses two wire assemblies for supporting the three heater filaments of a tri-gun cathode ray tube. The assembly is attached to and supported by one of the support rods used for holding the three electron guns in axial alignment. The assembly is made by welding two hairpin-shaped wires together and clipping the hairpin bend from each wire to form two parallel paths for the heater current to follow.

Background of the invention This invention pertains generally to apparatus for supportin the filamentary heaters in a tri-gun cathode ray tube having indirectly heated cathodes.

Various devices for supporting the filamentary heaters in a tri-g-un cathode ray tube have been developed. For the most part these devices use a great number of individual parts making assembly during production very tedious, time consuming and, of course, expensive. They also require a great number of welds to complete the assembly which tend to reduce the reliability of the guns due to the welds opening following strain on the filaments and support device.

It is an object of this invention to provide an improved device for supporting the cathode heating filaments of a tri-gun cathode ray tube which uses a minimum of parts thereby permitting rapid assembly during production.

It is another object of this invention to provide an improved device for supporting the cathode heating filaments of a tri-gun cathode ray tube that requires a mini-,

mum number of welds to assemble the device thereby increasing its reliability.

It is a further object of this invention to provide an improved device for supportin the cathode heating filament of a tri-gun cathode ray tube that provides for improved welded connections for added reliability.

It is another object of this invention to provide an improved method of assembling a device for supporting the cathode heating filaments of a tri-gun cathode ray tube that reduces production time and increases reliability.

Summary of the invention In one embodiment of this invention, a plurality of support rods hold the guns of a tri-gun cathode ray tube for a color television receiver in a parallel axial relationship, with the axis of each gun forming a vertex of an equilateral triangle. A support device formed from a pair of conducting members connects the three heater filaments of the guns in parallel and coaxially supports them in each gun for indirectly heating the cathodes. The support device is attached by a bracket to one of the support rods. Each conducting member includes a first substantially straight member having a portion attached to the bracket and a free end that extends from the support rod to the vicinity of one of the vertexes of the equilateral triangle. A second substantially straight member is mounted normal to the first member as a crosspiece and has first and second ends which terminate in 3,462,634 Patented Aug. 19, 1969 the vicinity of each of the two remaining vertexes formed by the axis of the guns. Each of the conducting members has a loop in the cross-piece member. The bracket holds the conducting members in a spaced relation from the support rod in which relation the cross-piece of one conducting member crosses the straight member of the other conducting member at the loop so that one conducting member does not contact the other member. In this manner, the conducting members provide two parallel paths for the heater current.

In assembling the support device, the two conducting members are each bent into a hairpin shape. They are fitted into a fixture and welded to each other to form a pre-assembly. Another fixture locates the conducting members to the support rod where they are welded in position. The hairpin bends are clipped from the conductor members, and the Wire legs of the filament heating elements are connected to the ends of the conductor members exposed by the clipping.

In the drawing:

FIG. 1 is a side elevation View of a portion of a cathode ray tube showing the tri-gun assembly in accordance with this invention;

FIG. 2 is a plan view of an end of the tube shown in FIG. 1 illustrating one embodiment of the support device in accordance with this invention;

FIG. 3 is a perspective view showing a step in assembling the device of FIG. 2;

FIG. 4 is a perspective view showin a second step in the method of assembling the device of FIG. 2;

FIG. 5 is a plan view of an end of the tube of FIG. 1 showing a second embodiment of the support device in accordance with this invention; and

FIG. 6 is a plan view of an end of the tube of FIG. 1 showing a third embodiment of the support device in accordance with this invention.

Description of the preferred embodiments Referring to the figures of the drawings, FIGS. 1 and 2 illustrate the neck portion 10 of a cathode ray tube 12 which can be used in a color television receiver. Sealed within the neck portion 10 are three

electron guns

14, 15 and 16 which are, respectively, the red, green and blue color guns. Each gun includes a cathode 13, surrounded by a control grid 19, a screen grid 17 and at least one accelerating electrode 18. The cylindrical electrodes such as 17, 18 and 19 of each electron gun are supported in spaced apart axial alignment by means of mounting straps 20 which are embedded in three support rods or

glass multiforms

22, 23 and 24. With the

electron guns

14, 15 and 16 being held in parallel axial alignment by the

multiforms

22, 23 and 24, the

axes

26, 27 and 28 respectively of the electron guns form the vertexes of an equilateral triangle shown in phantom in FIG. 2. A glass stem 30 seals the end of the neck portion 10 of the tube 12 and supports the stem leads 32.

The cathode 13 of each of the electron guns is indirectly heated by means of

heater filaments

36, 37 and 38 that axially extend into the cathodes. Extending from the heater filaments are wire filament legs or leads such as 36a and 36b (FIG. 1) to which is coupled through a filament connector assembly a current from two stem leads one of which is shown at 32a.

In the past various filament connector assemblies have been devised for supporting the filament heaters within the cathodes. In these devices, however, many small pieces have been used making assembly very tedious. Furthermore, because the filament heater leads are very fine, it hasbeen very difficult to get a good mechanical and electrical bond between the stem leads and the filament wire leads. The filament connecting and support assembly 45 in accordance with this invention, however, uses a minimum number of parts for simplicity and ease of assembly during production and also provides a unique manner for making the connections between the filament wire leads and the assembly.

FIGS. 3 and 4 show the method used for assembling the connector assembly 45. The material used for the connector assembly can be either wire or ribbon which is a good conducting member and is of a rigid material yet yieldable so that it may be formed into the desired shapes. As shown in FIG. 3, a first wire 47 is bent into the form of a hairpin and has two

loops

48 and 49 formed therein. A second wire 50 is also bent into the form of a hairpin, and has the

free ends

52 and 53 thereof bent back upon themselves so that they extend substantially normal to the plane of the hairpin.

The two

wire members

47 and 50 are preassembled in a jig and welded to each other as shown in FIG. 4. The side 55 of the member 47 is welded at 56 to the side 58 of member 50 in a manner so that the loop 49 prevents side 55 from contacting the side 60 of member 50. The side 62 of the member 47 is connected in a similar manner to member 50 by welding it to side 60 at 64 with the loop 48 positioned so that side 62 does not contact the side 58 of member 47. Therefore, with the two members so positioned and located to one another, the hairpin bends are clipped on each of the members leaving six

free ends

70, 71, 72, 73, 74 and 75 to form the connector assembly 45. By positioning the two

members

47 and 50 of the connector assembly in the manner described, two parallel conducting paths or

members

80 and 82 are formed. One member terminates in

ends

70, 72 and 75, and the other member terminates in

ends

71, 73 and 74. Thus, by using only two pieces, the

original wire members

47 and 50 are assembled into two parallel paths each path having three terminal end portions.

The next step in the assembly is to locate the connector assembly 45 with respect to one of the support rods by the use of a second jig. Once located to a support rod such as 22 in FIG. 2, the

sides

58 and 60 of the conducting

members

80 and 82 are Welded to a connector assembly support bracket 76. In this manner the connector assembly 45 including the two conducting

portions

80 and 82 are held in spaced relation to one another and extend substantially normal to the axis of the gun as shown in FIG. 1.

Each of the conducting

members

80 and 82 are similar and include, such as member 80, a straight portion which is side 60 that extends from the multiform 22 to the vicinity of the vertex 27 of the equilateral triangle, and a crosspiece which is side 62 of the member 80 which is normal to the straight portion 60. The cross-piece extends to a point where each of its

ends

73 and 74 terminate in the vicinity of the

vertexes

26 and 28 of the equilateral triangle. With both conducting

members

80 and 82 mounted in this fashion and in spaced relation to one another, there is provided parallel conducting paths for the filament current from the stem leads. One such stem lead is 32a which is welded to end portion 53 (FIG. 3) of the wire member 50 of assembly 45 as shown in FIG. 1. The wire leads 36a and 36b of the filament 36 in gun 17 are then connected to the

ends

73 and 72 of the

cross-piece members

62 and 55. The leads from the filaments 37 and 38 are connected in a similar manner to

ends

70 and 71 and 74 and 75 so that the filaments are connected in parallel to one another and with the heater current potential source.

FIG. shows a second embodiment of the filament connector assembly which uses a first conducting member 85 and a second conducting member 86, each conducting member is a mirror image of the other and is mounted to the connector assembly support bracket 76 in a similar manner to the first described embodiment. Each of the conducting members of this embodiment includes a first substantially straight portion 88 and a second portion 89 that is bent back upon the first portion and upon itself to substantially form a figure 4. The cross-piece 90 of the figure 4 at the point where the second portion 89 is bent back upon itself is located in the vicinity of vertex 26 of the equilateral triangle. The free end 92 of the crosspiece is located in the vicinity of the vertex 28 of the triangle, and the bend where the second portion 89 is bent back upon the first portion 88 is located in the vicinity of the vertex 27 of the triangle. The cross-piece is connected to the straight portion 88 and has a loop portion 94 that lifts the cross-piece 90 above the straight portion 96 of the second conducting member 86. By having each of the conducting members extending from the connector assembly support brackets 76 in a spaced relation and utilizing the loop portions so that neither member contacts the other, two parallel paths for connecting the filament wire leads and heater current are provided.

FIG. 6 illustrates a third embodiment of the invention which includes first and second conducting

members

100 and 102. Each conducting member such as 100 includes a first straight portion 104 which is connected to bracket 76. A second portion 106 is bent back upon the first straight portion 104 to form a portion of a first side of an equilateral triangle. The second portion 106 is further bent back against itself in two places and terminates in a free end 108 to form the second side 110 and most of the third side 112 of an equilateral triangle. Each of the corners of the equilateral triangle, which incldes the free end 108, lie in the vicinity of each of the

vertexes

26, 27 and 28 formed by the axes of the

electron guns

14, 15 and 16. The second conducting member 102 is formed by the axes of the

electron guns

14, 15 and 16. The second conducting member 102 is formed into an equilateral triangle in a fashion similar to conducting member 100 except that the sides of the triangle thus formed are longer than the sides of the triangle formed from conducting member 100. The straight portion 114 extends from the bracket 76 about the same distance as does the straight portion 104 of conducting member 100 so that the first sides of each triangle combined form a common base. Since the portion 106 of the first triangle is smaller than the portion 116 of the second triangle, the common base portions do not contact each other. The sides of the conducting member 102 are longer than the sides of the triangle formed from conducting member 100 and are positioned in a spaced relation by the bracket 76, so that they are substantially parallel. Therefore, the first and second conducting

members

100 and 102 do not contact each other and form parallel paths for the heater current to the filament leads.

FIG. 7 illustrates an improved way of making the connection between the filament leads and the connector assembly 45 so that once the weld is made the leads seldom, if ever, come open due to stresses on the heater filament element or on the connector assembly. In this embodiment, the connector assembly 45 described in conjunction with FIG. 2 utilizes conducting members which have their ends having a reduced cross-section compared with the body of the conductor. For instance, in conducting member 80, and ends 120 and 122 of the straight portion 60 have a substantially reduced cross-section compared with the remainder of the wire so that they may be easily crimped. In a like manner, ends 124 and 126 of the crosspiece 62 have similarly reduced cross-section so that they may be easily crimped. Therefore, with the conducting

members

80 and 82 welded io the supportt bracket 76 and extending in a spaced relation therefrom to the

vertexes

26, 27 and 28 of the equilateral triangle formed by the axes of the electron guns, the ends of reduced cross-section are in a position to be connected to the wire leads from the filaments. End 124 of cross-piece 62 is shown crimped about lead 36b from the heater filament 36. In this manner a tight mechanical bond is obtained between the reduced cross-section end 124 and the thin wire 36b. At the same time, the two wires are welded together so that an outstanding mechanical and electrical connection are made. It has been found under test conditions, that where previously the welded connections opened under a given stress,

the combined crimped and soldered connections remained intact. In a similar manner, thin stern leads such as 32a which couple the heater current to the connector assembly may also be connected to the connector assembly 34 by crimping the end 120 of straight portions 60 about the connector lead 32a and welding in place.

What has been described, therefore, is an improved device for supporting the cathode heating filaments of a tri-gun cathode ray tube which uses a minimum of parts, requires a minimum number of Welds to assemble the device and provides for improved welded connections therein.

Iclaim:

1. In a tri-gun cathode ray tube having a plurality of support members for holding the guns in axial alignment, each gun having filament means for indirectly heating the cathode, the combination including, a filament connector assembly including first and second conducting members, support means for rigidly supporting each conducting member in spaced relation to one another, each said first and second members extending from said support means in a cantilever fashion in a spaced relation to the guns and having portions extending to a point in the vicinity of the axis of each of the guns, and means coupling the filament means of each gun to each of said conducting members at said extended portions so that said conducting members firmly support said filament means.

2. The tri-gun cathode ray tube of claim 1 wherein the means for rigidily attaching each conducting member includes a support bracket attached to one of the support members, said conducting members being fixed to said support bracket substantially normal to the axis of the guns and in a spaced relation to one another.

3. The tri-gun cathode ray tube of claim 1 wherein the means for coupling the filament means to said conducting members include filament legs extending from the filament, and wherein said conducting members are formed from a stifi but yieldable material, and said portions of said conducting members in the vicinity of the axis of each gun have a reduced cross-section, said reduced cross-section being crimped about said filament legs to form a good electrical and mechanical bond therewith.

4. A tri-gun cathode ray tube for a color television receiver having a plurality of support rods holding the guns in parallel axial relationship with the axis of each gun forming the vertexes of an equilateral triangle, the tube including in combination, filament means for indirectly heating the cathode of each gun, filament support means for coaxially supporting said filament means in each gun, said filament support means including first and second conducting members, support means for said first and second conducting members for supporting the same with respect to the guns and to each other, each of said conducting members having one end connected to said support means and extending from the same with the other end being unsupported, said conducting members being positioned in a spaced relation with respect to one another to the vicinity of each of the vertexes of the equilateral triangle, and means connecting said filament means to said conducting member so that said conducting member firmly supports said filament means, and provides parallel paths for coupling a potential thereto.

5. The tri-gun cathode ray tube of claim 4 wherein each conducting member includes a first substantially straight member having a portion attached to said support means and having a free end extending from the support rod to the vicinity of one of the vertexes of the equilateral triangle, and a second substantially straight member mounted substantially normal to said first member as a cross-piece and having first and second ends which terminate in the vicinity of each of the two remaining vertexes respectively, each said conducting member having a loop in said cross-piece member, said crosspiece of one conducting member crossing said straight portion of the other conducting member at said loop with each conducting member extending in a spaced relation from said support means so that one conducting member does not contact the other conducting member.

6. The tri-gun cathode ray tube of claim 4 wherein each conducting member is a mirror image of the other conducting member and includes a first substantially straight portion connected to said support means and extending to the vicinity of one vertex of the equilateral triangle, and a second portion bent back upon the first portion and upon itself to substantially form a figure 4, said conducting member having the cross-piece of the figure 4 at the point where the second portion is bent back upon itself being in the vicinity of one of the remaining vertexes of the equilateral triangle, and the free end of said cross-piece being in the vicinity of the remaining vertex of the triangle, said cross-piece of said figure 4 being connected to the straight portion thereof and having a loop therein, said cross-piece of one conducting member crossing said straight portion of the other conducting member at said loop with each conducting member extending in a spaced relation from the support rod so that one conducting member does not contact the other conducting member.

7. The tri-gun cathode ray tube of claim 4 wherein each conducting member includes a first straight portion attached to said support means, and a second portion bent back upon the first portion to form a portion of a first side of an equilateral triangle, said second portion being further bent back against itself in two places and terminating in a free end to form the second side and a portion of the third side of the equilateral triangle, each of the corners of the equilateral triangle including the free ends respectively lying in the vicinity of each of the vertexes of the equilateral triangle formed by the axis of the guns, said sides of said triangle formed by one conducting member being longer than said sides of said triangle formed by the other conducting member, and each said straight portion attached to said bracket extending approximately the same distance therefrom so that said first sides of each triangle form a common base for both triangles, said first side of one triangle being shorter than said first side of the other triangle and spaced therefrom, and said second and third sides being positioned so that they are substantially parallel so that said first and second conducting members do not contact one another.

8. A tri-gun cathode ray tube for a color television receiver having support means for holding the guns in parallel axial relationship with the axis of each gun forming the vertexes of an equilateral triangle, and having filament means for indirectly heating the cathode of each gun, the tube including in combination, filament support means for coaxially supporting the filament means in each gun, said filament support means including a plurality of conducting members, means for attaching said conducting members to the support means for supporting the same with respect to the guns and to each other, said conducting members having portions extending to the vicinity of the vertexes of the equilateral triangle, and wire leads for connecting the filament means to said portions, said portions of said conducting members in the vicinity of the vertexes of the triangle having reduced cross-sections relative to the cross-section of said conducting members, said reduced cross-section portions being crimped about said wire leads to provide a good electrical and mechanical bond therewith.

9. The tri-gun cathode ray tube of claim 8 further including two stem leads for coupling a current to said filament means, and wherein at least one of said conducting members further includes terminal portions, said terminal portions having a reduced cross-section relative to said cross-section of said conducting member, said reduced cross-section of said terminal portions being crimped 7 about a respective stem lead to make a good electrical and mechanical bond therewith.

10. A method of assembling filament heating elements to support means in a tri-gun cathode ray tube, including the steps of, bending conductive members into a. hairpin shape, preassembling the conducting members, locating the conducting members to the support means, fixing the conducting members to the support means, clipping the hairpin bends from the conducting members, inserting the filament heating elements into the cathodes of the electron guns, and connecting the filament heating elements to the conducting members.

11. The method defined in claim 10 further including the steps of selecting two conducting members and bending each into a hairpin shape, preassembling the two conducting members to each other in a fixture, welding the two conducting members into a connector assembly, locating the connector assembly to the support means, welding the connector assembly to the support means, clipping the hairpin bends from each conducting member, inserting the filament heating elements into the cathodes of the electron guns, and Welding the filament heating element the ends of the conducting members exposed by the clipping.

References Cited UNITED STATES PATENTS 3,23 8,409 3/1966 Brown 3l3-271 3,134,923 5/1964 Brown 313-271 3,387,166 6/1968 Kraner et al. 31370 X 3,391,298 7/1968 Dorota 313271 JOHN W. HUCKERT, Primary Examiner R. F. POLISSACK, Assistant Examiner US. Cl. X.R.