US2918598A - Anode mount for electron tubes - Google Patents

Description

Dec. 22, 1959 G. M NEILL ROSE, JR, ET AL ANODE MOUNT FOR ELECTRON TUBES INVENTORS EEUREE M. REJSLJR. E

By WILLIAM J. HELWIE Filed June 7. 1957 United States Patent ANODE MOUNT FOR ELECTRON TUBES George McNeil] Rose, Jr., Mountain Lakes, and William John Helwig, Kearny, N.J., assignors to Radio Corporation of America, a corporation of Delaware Application June 7, 1957, Serial No. 664,250

11 Claims. (Cl. 313-284) The present invention relates to anode mounts for electron tubes, and particularly to a mount including a tubular wall member and a unitary tubular structure comprising an anode portion and an exhaust tubulation portion, and having lateral extensions of relatively small area engaging the inner wall of the tubular wall member for desired orientation and support within the wall member.

One environment in which the invention finds particular utility, is in the structure of an electron tube known as the pencil type. This tube type is elongated in shape and includes two spaced tubular metallic wall members constituting end portions of the tube. One of such Wall members supports a tubular or sleeve type cathode and forms therewith a cathode mount, and the other of the wall members, in association with a tubular anode supported thereby constitutes an anode mount. Also forming part of the anode mount is an exhaust tubulation, which cannot be accommondated advantageously in the cathode mount due to the presence of cathode heater leads in the free end of the latter mount. The pencil tube may also include a tubular grid mounted on an apertured metallic disc sealed across an intermediate tubular wall portion made of insulating material. The tubular electrodes aforementioned are disposed in concentric relation when appropriately assembled in a completed tube.

The invention is characterized by many advantages, some of which will become apparent from a consideration of the following purposes which it accomplishes.

One important purpose is to provide an improved anode mount for an electron tube.

A further aim of the invention is to provide an anode mount contributing to facility in assembling parts forming an electron tube.

Another purpose is to provide an anode mount having an anode and an exhaust tubulation incorporated in a unified structure prior to inclusion in the mount, for reducing the number of assembling operations in the manufacture of a tube.

A further object of the invention is to provide an anode mount including means for automatically and accurately orienting an anode in a support.

Another aim is to provide an anode mount wherein an anode is adapted to be mounted in a support constituting a portion of a tube envelope, after the support has been sealed to other portions of the envelope. The accomplishment of this aim serves to protect the anode from adverse effects of the sealing operation.

A further purpose is to provide an anode mount including a tubular support and a tubular anode-exhaust tubulation unit engaging the inner wall of the support in relatively small area regions. Another object is. to provide a tubular anode-exhaust tubulation unit for an anode mount, having an annular emboss'ment or extension serving the dual function of desirably locating the unit in a tubular support and providing a region for mechanically joining two portions of different material constituting the unit referred to.

Briefly considered, one embodiment of an anode mount according to the invention, comprises a tubular support constituting an end portion of a tube and within which is mounted a tubular unit comprising an anode and an exhaust tubulation. The tubular unit is. provided with projections or bulges in its outer surface which constitute the only portions of the tubular unit that engage the tubular support, for orienting the unit in desired transverse relation to the support. For orienting the unit longitudinally of the support, one of the bulges, which is larger than the other, is caused to engage a flared inner wall of the support adjacent to one end of the support.

In addition to its spacing function, one of the bulges may be utilized for joining an anode of one material to 'an exhaust tubulation of another material for preserving the unit character of the combined anode and exhaust tubulation.

The foregoing structure permits tube envelope portions, including the tubular support, to be sealed together prior to mounting the anode therein, thereby preserving the anode from harm during the sealing operation. It also provides desired access, prior to mounting the tubular unit into the interior of the envelope, for mounting other electrodes, such as a grid, therein.

Further objects and advantages will become apparent as the present description proceeds.

Referring now to the drawing for a more detailed consideration of embodiments incorporating the invention,

Fig. 1 shows an elevation in cross-section of an electron tube having an anode mount in accordance with the invention and in which the anode and exhaust tubulation of the unit they comprise, are made of different materials;

Fig. 2 is a fragmentary view in cross-section of a portion of a tube including the anode mount of the invention and wherein the anode-exhaust tubulation unit is integral and made of the same material throughout;

Fig. 3 is a sectional view of a tool and a work piece that may be used in producing certain of the bulges in an integral portion of the anode-exhaust tubulation unit by deforming the material thereof, the tool being shown prior to a forming operation;

Fig. 4 is a fragmentary view in cross-section showing the tool and work piece of Fig. 3 after a bulge forming operation;

Fig. 5 is a fragmentary sectional view of a tool and work pieces prior to a forming operation for providing a joint type bulge wherein two work pieces are joined to form an anode-exhaust tubulation unit;

Fig. 6 is a fragmentary sectional view of the tool and work pieces shown in Fig. 5, after the forming operation has been completed; and

Fig. 7 is a view partly in phantom, of a modified anode exhaust tubulation unit, and wherein a projection thereon is formed by a ring extending around and fixed to the unit.

As shown in Fig. 1, an anode mount according to the invention, may be used conveniently in a pencil type tube comprising an envelope including metallic tubular end portions 10, and 11, joined by two cylinders 12, 13 made of insulating material, such as glass or ceramic. The two cylinders referred to are joined by suitable seals to a metal disc 14.

Within the envelope described, are disposed at least two electrodes, three being shown for purposes of illustration. The three electrodes comprise a cathode 15, a

grid 16 and an anode 17. The cathode 15 is supported on a suitable tubular member 18, brazed or force fitted to the inner wall of envelope end portion 11. The grid 16 is supported on the disc 14 by suitably engaging walls 19 defining an opening in the disc, which opening also provides clearance for extension of cathode 15 therethrough. The anode 17 forms a part of an anode-exhaust tubulation unit 19 which also includes an exhaust tubulation 20. This unit, which embodies an important feature of the invention, will be described more fully in the following.

It will be noted that the exhaust tubulation 20 is disposed at the end of the tube remote from the cathode support 18. This disposition of the exhaust tubulation is dictated by the fact that the cathode support end of the tube includes heater leads 21, connected to cathode heater 22. The presence of these leads would interfere with a. positioning of the exhaust tubulation at the same end therewith. This consideration, therefore, makes it necessary for the anode and exhaust tubulation to appear at the same end portion of the tube.

Heretofore, the anode, although mounted in the same end portion of the tube as the exhaust tubulation, has constituted a separate structure from the exhaust tubulation. Indeed, the anode was heretofore fixed in the tube end portion as an insert, prior to sealing said end portion to incorporate it in the tube envelope structure. This premounting of the anode in the appropriate tube end portion was performed primarily to protect the envelope from the appreciable force necessary for insertion of the anode into said portion.

While the aforementioned premounting of the anode was thus considered necessary by reason of the tube construction used heretofore, this practice was accompanied by several difiiculties.

One difliculty resided in the fact that the pre-insertion of the anode in end portion 10, reduced appreciably the size of the opening in the end portion to the interior of the envelope. Such reduction in opening size precluded the use of certain desirable techniques for mounting the grid 16 on the apertured disc 14.

A further difficulty arose from the fact that the end portion 10 was sealed to the remainder of the tube envelope, after a mounting of an anode in such end portion. This exposed the anode to conditions required for making the seal which sometimes were of such character as to harm the anode. For example, objectionable restriction was placed on the choice of anode material, thus rendering some materials which might be of particular advantage for the anode, objectionable because of their adverse reaction, such as oxidation of the anode surface, to the sealing conditions.

Another respect in which the prior practice referred to was deficient, involved the separate structures of the anode and exhaust tubulation. Such separate structures required separate assembly or mounting operations. Thus, it was found impractical to mount the exhaust tubulation at the same time that the anode was mounted, since this would require a mounting of the exhaust tubulation prior to sealing its associated tube end portion to the envelope. The presence of the exhaust tubulation, as an extension from such end portion, prior to the sealing operation, would require special handling of the end portion during sealing.

According to the invention, the exhaust tubulation 20 and the anode 17 are parts of a unitary structure 19. The exhaust tubulation 20 and the anode 17 may be made of two parts of different material, as shown in Fig. 1, or they may constitute an integral unit as shown in Fig. 2. It is, of course, feasible to make the two parts of the unit 19 shown in Fig. l, of similar materials, Where this is desired.

Referring to Fig. 1, the unitary structure referred to includes two lateral bulges or outwardly extending projections 23, 24. The bulge 24, extends radially or laterally of unit 19, to provide a snug fit with straight inner wall portion 25 of tube end portion 10. Bulge 23 extends farther laterally from the unit 19, than bulge 24. Bulge 23, therefore, traverses the larger area defined by the flared portion 25a of the inner wall of the end portion 10, adjacent the free end thereof. The bulge 23 is of a size to extend sufficiently into the end portion 10 to provide a cavity 26 for conveniently accommodating brazing material 27 which may be of ring shape, employed to fix the unit 19 in the envelope end portion 10.

The position of the unit 19 in the end portion 10 is determined by the bulges 23, 24. Both of the bulges serve to orient the unit 19 in desired coaxial relation with respect to the envelope end portion 10. In addition, bulge 23 serves to orient the unit 19 in desired longitudinal relation with respect to end portion 10. This follows from the fact that the size of bulge 23 and the slope of the flared portion 25a, determine the extent of entrance of the unit 19 into the end portion aforementioned.

The bulges 23, 24, may extend annularly continuously around the unit 19, or if desired, may be in the form of annularly spaced embossments.

In either embodiment, the bulges 23, 24 present rela tively small area surfaces for engaging the inner Wall of end portion 10. This small area engagement is of advantage when inserting the unit 19 intothe end portion referred to. This advantage flows from the fact that the reduction in engaging areas reduces friction between the unit 19 and the end portion 10, during the inserting operation, as a consequence of which it is feasible to mount the unit 19 in the end portion 10, after the end portion has been scaled to the cylinder or collar 12 for forming the tube envelope. The reduced friction permits the inserting operation to be performed with a force of relatively small magnitude and insulficient to harm the seal aforementioned.

It will be noted that the anode 17 and exhaust tubulation 20, are thus effectively mounted in the end portion 10, in a single mounting operation. And due to the relatively small force required to effect the desired mounting, the mounting operation can conveniently be deferred until after the sealing of end portion 10 to the cylinder 12 has been completed, and indeed, after the grid 16 has been suitably mounted by tools requiring unimpeded access through the opening in end portion 10.

The two part construction of the unit 19 shown in Fig. l is of particular advantage in situations where one material is found to be best for the exhaust tubulation 20, and another and different material most suitable for the anode 17. For example, copper is advantageous as the material of the exhaust tubulation, since it lends it-. self to a convenient tip-01f 28 by a weld requiring pressure only and no deliberate application of heat. Furthermore, copper is ductile and readily permits the formation of bulges 23, 24 thereon. However, the invention is not limited to the use of copper, and any other suitable material may be employed. With respect to the anode, we have found that titanium possesses advantage by reason of its gettering action. Due to the small space defined by the envelope of a pencil type tube under discussion, it may be feasible to omit conventional getter structures and rely entirely on the gettering function of the titanium anode. However, the anode 17 of the unit 19, may be made of any other desired material, and indeed may be made of a material similar to that of the exhaust tubulation 20.

The anode mount shown in Fig. 2 is similar to that of Fig. 1, except that the anode-exhaust tubulation unit 29 of Fig. 2 is an integral structure, made from a single piece of tubing. It includes an exhaust tubulation portion 30 tipped off at 31, and an anode portion 32. The envelope end portion 33 is similar to end portion 10 of Fig. 1. Bulge 34 serves the same function as bulge 23 of Fig. l, but bulge 35 serves a locating function only. The unit :29 may be made of copper or any other suitable materia Figs. 3 and 4 show tools that may be used in forming the bulge 23 of Fig. 1, and bulge 35 of Fig. 2. The tool includes a member 36 movable in opposition to a member 37. Member 36 is provided with an annular recess 38 for receiving one end portion of a tubing 39 and has an offset annular portion40. It also includes a rod portion 41 extending appreciably above, the offset 40 for restraining inward; movement of the portion of the tub ingabove the offset 40 and which is tofbe deformed to provide a bulge. The member 37 is provided with an offset 42, which is deeper than offset 40. This increased depth provides a recess 43 shown in Fig. 4, formed when the end portion 44 of member 37 abuts against shoulder 45 on the member 36. The member 37 is provided with an annular ledge 46 which is adaptdto engage onefend of the tubing 39,with the result that when the two members 36, 37 are brought together to the position shown in Fig. 4, the tubing material, is deformed adjacent the offset 42 and is urged into the r'ecess43 formed by the offset. The offset 42 may be roundedfas at 47 and the end portion 44a rounded as shown, to round the extremity of the bulge, to further reduce the area of contact between the bulge and the envelope end portions and 33. A slightly different tool, not shown, may be used to form the second bulge 34 to a larger size than bulge 35, for a purpose discussed before herein.

The foregoing indicates one way in which the bulge 23 of Fig. 1 and the bulges 34, 35 of Fig. 2, can be made. However, bulge 24 is made in a different way to be explained in the following.

As shown in Figs. 5 and 6, the bulge 24 is made by using two preformed work pieces 48, 49. Work piece 48 is a tubular structure having a cup-shaped flange 50. Work piece 49 is also tubular but is provided with a relatively small flange 51 adapted to fit into the cup-shaped flange 50. The tool employed for making this bulge includes a member 52 having an annular recess for receiving the Work piece 49 with its flange 51 extending above the recess. Member 52 also includes a rod por tion 53 for confining movement of the material of flanges 50, 51, during a forming operation. The tool also includes a member 54 having a rounded recess 55, which, when the two tools are moved towards each other as shown in Fig. 6, cooperates with rounded end portion 56 of member 52, to form a recess 57, in which the flange 50 is urged LO embrace flange 51 for effectively joining the two work pieces. Instead of forming the bulges by upsetting the ma tcrial of the tubular work piece, it is feasible to provide a structure as shown in Fig. 7, having a similar function, by substituting for the bulges 34, 35 and 23, suitable rings, 58 fixed to the tubular work pieces as by brazing or swaging at predetermined locations thereon.

It will then be seen that the invention contributes to an improved anode mount having many advantages. For example, the anode-exhaust tubulation unit is capable of appreciable modification in its diameter, without requiring change in the envelope portions 10 and 33. The bulges aforementioned are capable of accommodating within the envelope portions aforementioned, a unit of any desired diameter within a range determined by the inner diameter of the end portions 10 and 33, without requiring a change in such inner diameter. Therefore, the end portions 10 and 33 may be identical to end portion 11 shown in Fig. 1 and which accommodates cathode support 18. This interchangeability of parts is an appreciable advantage in manufacturing a tube of the type discussed. Other advantages, pointed out before herein, combine to, provide an electron tube having superior structural features and characterized by increased facility in manufacture.

We claim:

1. An an'ode mount comprising a tubular envelope portion having an inner wall, said wall having one group of opposite portions spaced farther than another group of opposite portions, and a tubular unitary structure within said envelope portion, said structure having outwardly extending bulges therein, one of said bulges being larger than the other, said larger bulge engaging said one group of opposite portions for orienting said structure longitudinally in said envelope portion, the other of said bulges engaging said another group of opposite portions for desirably orienting said structure laterally in said end portion.

2. An electron tube having a tubular metallic portion having an inner wall, said inner wall including a first region flared outwardly from the axis of said portion, and a second region spaced axially from said first region and defining a smaller area than said first region, a tubular unitary structure within said end portion, said structure having laterally extending projections, one of said projections engaging said first region for longitudinally orienting said structure in said tubular portion, another of said projections engaging said second region for laterally orienting said structure in said tubular portion, said projections only, engaging the inner wall of said tubular portion, for orienting said structure in said end portion, and means adjacent to one of said projections for fixing said structure to said end portion.

3. An anode mount including a tubular support, a unitary tubular structure comprising an anode and an exhaust tubulation in said support, means fixed to said structure for spacing said structure in said support, and for disposing a relatively large portion of said structure out of contact with said support, and means adjacent to said first named means for fixing said structure to said support.

4. An anode mount including a tubular support having a portion of its inner Wall adjacent to one end thereof tapered toward said end, and another portion of said wall spaced from said tapered portion and having parallel opposite portions; and a unitary tubular structure including an anode disposed within said support, said tubular structure having two lateral projections at longitudinally spaced portions thereof, one of said projections being larger than the other and engaging an intermediate region of said tapered portion for longitudinally orienting said tubular structure in said support, the other of said projections engaging said another portion of said wall for transversely orienting said structure in said support.

5. A unitary tubular structure for an anode mount, said structure having opposite end portions, one of said end portions being made of a ductile metal, for effective closure by a pressure weld and constituting an exhaust tubulation, the other of said end portions being made of another material, and means extending laterally from said structure and adapted to orient said structure when incorporated in said mount.

6. A unitary tubular structure for an anode mount, said structure having opposite end portions, one of said end portions being made of a ductile metal, for effective closure by a pressure Weld and constituting an exhaust tubulation, the other of said end portions being made of another material, and means extending laterally from said structure and adapted to orient said structure when incorporated in said mount, said means including an annular bulge in the outer surface of said structure, said bulge including a portion of said exhaust tubulation and said anode in mechanically interlocked relation.

7. A unitary elongated tubular structure having opposite end portions, one of said end portions being made of copper for effective closure by a pressure weld and constituting an exhaust tubulation, the other of said end portions being made of titanium and adapted to serve as a combined anode and getter, and means extending laterally from said structure and adapted to orient and support said structure when incorporated in a tube mount, said means only having engageable surfaces of relatively small areas for reducing heat losses from said other of said end portions for preserving its gettering action.

8. In an electron tube mount, an exhaust tubulation having locating projection in a side thereof, said projection extending longitudinally of said tubulation a shorter distance than said side, and a tubular anode having one end thereof mechanically interlocked with said exhaust tubulation in said projection.

9. In combination, an anode made of a material having improved gettering properties at elevated temperatures, an exhaust tubulation, said anode being supported solely by said exhaust tubulation, and a tubular support for said exhaust tubulation, said exhaust tubulation having relatively small area lateral projections, said projections only, engaging said support, whereby said anode is preserved from heat losses by conduction to said support, for improving said gettering properties.

10. In an electron tube mount, an integral tubular structure having one 'end portion constituting an exhaust tubulation, and another end portion constituting an anode, said one end portion only, having at least one lateral projection thereon adapted to support said structure in said mount.

11. In combination, a tubular exhaust tubulation, tubular anode, sai'cl exhaust tribulation having a bulge in one end thereof, said anode being interlocked with said exhaust tubulation atjisiaid bulge, and a tubular support, said exhaust tubulation being. disposed in said tubular support with said bulge engaging" an end portion of said support, and said anode extending outside of said support and from said end portion thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,395,991 'C hilcot et al Mar. 5, 1946 2,414,137 Bran'sou Jan. 14, 1947 2,417,061 'Chilcot et *al. j. Mar. 11, 1947 2,422,872 Wolfe June 24, 1947 2,473,969 Pryslak et al. June 21, 1949 2,582,684 Drie'schman et a1. Ian. 15, 1952 2,708,249

Pryslak May 10, 1955

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