US3263299A

US3263299A - Assembly method for electron discharge devices

Info

Publication number: US3263299A
Application number: US463725A
Authority: US
Inventors: Stan W Lemaster; William B Mesplay
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1962-04-05
Filing date: 1965-06-14
Publication date: 1966-08-02
Anticipated expiration: 1983-08-02

Description

s. w. LEMASTER ETAL 3,263,299

ASSEMBLY METHOD FOR ELECTRON DISCHARGE DEVICES 2 Sheets-Sheet 1 Aug. 2, 1966 Original Filed April 5 1962 INVENTORSI STAN W. LEMASTER WILLIAM B. MESPLAY BY J THEI

ATTORNEY Aug. 2, 1966 s. w. LEMASTER ETAL 3,253,299

ASSEMBLY METHOD FOR ELECTRON DISCHARGE DEVICES 2 Sheets-Sheet 2 Original Filed April 5, 1962 FlG.5b

FIG. 6(1

FIG 6 b INVENTORS'.

STAN W. LEMASTER. WILLIAM B. MESPLAY.

b LL (1 A L y.

T H Ef R ATTORNI EY 2 Claims. c1. 2s 2s.1a

This is a division of application Serial No. 185,260, filed April 5, 1962.

This invention relates to a mount assembly for electron discharge devices and, in particular, to an assembly for mounting a plurality of electron discharge devices within a single envelope.

In the manufacture and use of electron discharge devices it has been found to be advantageous to mount several complete electron discharge devices within a single envelope for purposes of economy of construction, operation, and space. Such structures require that the individual electron discharge devices and the various electrodes of each be arranged in closely spaced relation. The electrode elements of the electron discharge devices are normally supported between spaced insulators such as laminated mica discs by insertion of the end portions of the electrode elements into properly located apertures in the spaced insulators, to thereby maintain the electrode elements in spaced relation.

Several problems arise in the manufacture of an electron tube of the type in which several electron discharge devices are contained within the tube envelope. The necessary close spacing of the individual electron discharge devices and their respective electrodes requires that a large number of accurately located, punched apertures be made in small area mica discs so as to receive the end portions of the electrode elements. Mica tends to de-laminate when pierced and the tendency is increased in proportion to the number of holes in a given mica disc. Thus, the great number of apertures mechanically weakens the mica supports and, further, requires complex dies for their formation.

A problem also arises in the mechanical operation of inserting the end portions of the electrode elements into the proper locating apertures in the mica discs. Each of the electrode elements, e.g., cathode, plates, grids, usually requires at least two tabs, ears, or legs, i.e., at least one at each end of the electrode element, for support and alignment. When a large number of electrode elements are employed in a limited space, it becomes very difficult to pass the multitude of tabs, ears, or legs through the apertures in the mica supports.

The difficulty is aggravated when the mounting of the electrode elements is effected by mechanized or automated means, since all the elements must be perfectly aligned and held while the apertured mica supports are secured to the electrode elements. Also, the aligning tools must remain in correct alignment with respect to the mica supports while being withdrawn from the assembled unit, otherwise a force will be exerted on the mica supports tending to de-laminate them. Mechanized equipment designed for assembly of the prior art mount structures becomes very complicated and its complexity increases with the number of electrodes in a given structure. When multi-element type electron discharge devices, as for example, twin triodes, tetrodes, pentodes, heptodes, etc., are mounted within a single envelope, the mechanized equipment required for assembly may become prohibitively complicated.

It is an object of the invention to provide an improved method of assembly for mounting a plurality of electron discharge devices within a single envelope.

United States Patent It is another object of the invention to provide a simplified method of assembly for mounting a plurality of electron discharge devices within a single envelope which facilitates the mounting of electrodes between support elements.

It is a further object of the invention to provide an assembly for mounting a plurality of electron discharge devices within a single envelope which incorporates a member for electrostatically and/or electromagnetically shielding the individual devices from each other and which facilitates the integration of the individual devices into a rigid unit.

In accordance with the illustrated embodiments of the invention, each of the electron discharge devices to be incorporated into a single envelope is individually mounted on respective insulative supports which are apertured to receive the ends of the electrode elements. A metallic member is interposed between the respective electron discharge devices to electrostatically and/ or electromagn-etically shield the devices from each other. The shield member is shaped so as to be adaptable for ready attachment to each of the individual electron discharge devices, thereby serving to integrate the individual electron discharge devices into a single unit. The insulative supports of the individual electron discharge devices are shaped so as to be complementary so that, upon assembly into a unit, the periphery of the insulative support combination corresponds generally to the shape of the inside wall of the envelope so as to aid in supporting the unit within the envelope.

The subject matter of the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of the mount assembly of the invention according to a first embodiment;

FIG. 2 is an enlarged side view illustrating the assembly of the individual electron discharge devices into an integral unit by means of the shield member;

FIG. 3 is a partially cut-away isometric view of a tube incorporating the mount assembly of the invention;

FIG. 4 is an alternative embodiment of the invention;

FIG. 5(a) and FIG. 5(b) illustrate a type of ear and slot combination which may be used in the embodiment of FIG. 4; and

FIG. 6(a) and FIG. 6(b) illustrate another type of ear and slot combination which may be used in the embodiment of FIG. 4.

With reference to FIG. 1 the structural relationship of the mount assembly of the invention is shown with a shield member 10 interposed between two electron discharge devices. A first electron discharge device 11, here shown merely by way of illustration to be a pentode, is mounted between spaced mica insulator supports 12 and 13, with the electrodes maintained in spaced relationship by virtue of apertures in the mica segments. The end of cathode 14 protrudes through the mica 12 as shown, while the support rods 15 of the control grid, the screen grid support rods 16, and the suppressor grid support rods 17 similarly protrude. Anode 18 is maintained in position by tabs 19 which extend through slots in the

mica segments

12 and 13 and are bent to lie flat against the mica segment.

A second electron discharge device 20, also illustratively shown as a pentode, is similarly mounted between spaced mica insulator supports 21 and 22. The end of cathode 23 is shown protruding through mica segment 21. Control grid support rods 24, screen grid support rods 25, and suppressor grids support rods 26 similarly extend through apertures in the mica segments which serve to support the electrodes and maintain them in spaced relation. Anode 27 is positioned by tabs 28 which extend through corresponding apertures in the mica segments and are bent down against the mica segments.

Electron discharge device 11 and electron discharge device 20 are combined into a rigid integral unit, in accordance with the invention, by means of metallic shield 10, having a planar main element 31 and side elements or

flanges

32 and 33 attached to the main element 31 along opposed edges thereof. The shield member is interposed between electron discharge device 11 and electron discharge device to preclude electrostatic interaction of the electron discharge devices. If the shield member 10 is comprised of high permeability magnetic material, it will serve to electromagnetically as well as electrostatically shield the electron discharge devices from each other.

Electron discharge device 11 is mounted on shield 10 by the insertion of tabs 34, which extend from the

side elements

32 and 33 of shield 10, into slots 35, formed in

mica segments

12 and 13. The shield 10 may be positioned between the

mica segments

12 and 13 during assembly of electron discharge device 11. After assembly of electron discharge device 20, electron discharge device 20 and electron discharge device 11 are combined into a rigid integral unit by inserting tabs 36, extending from the

side elements

32 and 33 of shield 10, into slots 37, formed in mica segment 21. Mica segment 22 of electron discharge device 20 bears against the shoulders 38 of

side elements

32 and 33, thereby rendering electron discharge device 20 axially immovable relative to shield 10. Permanent rigid attachment of electron discharge device 20 to shield 10 is effected by bonding tab 39, which is affixed to and extends from main element 31 of shield 10, to a suitably positioned anchor on the lower surface of the support 22, which may conveniently be the projecting end of grid side rod 26 as shown more clearly in FIG. 2.

Mica

segments

12, 13 and 21, 22 are shaped so that upon attachment of the electron discharge devices to shield 10, the periphery of the adjacent mica segments corresponds generally to the shape of the inside wall of the tube envelope. Triangularly formed snubbers 41, extending from the periphery of

mica segments

12, 13, 21 and 22, contact the inner walls of the envelope to provide lateral support for the mount assembly within the envelope.

As shown in FIG. 1, the electron discharge devices need not be of the same axial length. Main element 31 of shield 10 may be formed to correspond to the axial length of the longer electron discharge device to be incorporated into the envelope, in order to provide effective shielding. The shield is adapted to the other electron discharge device by forming and positioning the shoulders 38 so as to correspond to the axial length of the shorter device. The Weld tab extending from the shield is similarly repositioned to correspond to the location of the rod 26 (FIG. 2) of the other electron discharge device to which it is to be bonded. Thus, the invention may be used to integrate into a rigid unit electron discharge devices of the same or different axial lengths.

FIG. 2 illustrates the method of combining the shield 10 and

electron discharge devices

11 and 20 into an integral unit. As previously described, shield 19 is mounted between

mica segments

12 and 13 of electron discharge device 11 by virtue of the insertion of tabs 34 into corresponding slots 35 in the mica segments during assembly of electron discharge device 11. Thus, shield 10 becomes an integral part of electron discharge device 11. Electron discharge device 20 is mounted by insertion of tabs 36 of shield 10 into slots 37 of mica segment 21 and rotating electron discharge device 20 toward shield 10 utilizing the ear and slot combination as a pivot. Thus, the interior surface of mica segment 22 is brought to bear against shoulder 38 of shield 10. Permanent attachment is secured by bonding tab 39 to the support rod 26 extending through mica segment 22, as for example by welding tab 39 to rod 26. Thus, shield 10 and

electron discharge devices

11 and 20 are combined into a rigid integral unit.

FIG. 3 illustrates the mount assembly of the invention positioned within a tube envelope 43 which may be evacuated to any desired degree. Snu-bbers 41 contact the interior wall of the envelope 43 to firmly secure the mica supports and hence the electron discharge devices so as to render them laterally immovable. Leads 44 connect the various electrodes to the pin connectors 45 and serve to render the unit immovable axially within the envelope. The pin connectors 45 function to connect suitable sources of energizing potential, not shown, to the electrodes.

FIG. 4 illustrates an alternative embodiment of the invention wherein the mounting of

electron discharge devices

11 and 20, as an integral unit, is accomplished by utilizing a different shield configuration. Shield comprises a planar main element 51 which is interposed between the electron discharge devices.

Side elements

52 and 53 are attached to the edges of the main element 51 and lie in planes generally perpendicular to main element 51. Compressible ears 54 extend from the

side elements

52 and 53. Apertures 55, shaped to receive compressible ears 54, are formed in

mica segments

12, 13, 21, and 22. Apertures 55 comprise slots extending inwardly from the edge of the mica segments and having enlarged end portions for receiving and locking the compressible ears in place. Thus, the ears 54 are compressed while passing through the slots and subsequently expand in the enlarged end portions of the slots to securely lock and rigidly attach the mica supports and hence the associated electron discharge devices to the shield. The employment of the welded tab, described hereinabove in connection with the embodiment of FIGS. 1-3, is thereby obviated. The motion involved in the assembly is also simplified, requiring only pure translation as opposed to the rotational motion required in the first embodiment.

While the alternative embodiment of FIG. 4 shows electron discharge devices of the same axial length, the invention may be applied to mounting electron discharge devices of different axial lengths by simply making the dimension of the respective portions of the

side elements

52 and 53 correspond to the distance between the mica supports of the electron discharge device to be mounted thereon.

It will be understood that a further modification of our invention contemplates the use of an expansion tab and lock-mica slot arrangement similar to that shown at one end of the shield in FIG. 4, in place of the shoulder and tab arrangement shown in the shield of FIGS. 1 and 2, in which case the use of the tab connection welded to the grid side rod could also be obviated.

FIGS. 5(a) and 6(a) are plan views of other forms of compressible ears which can be employed in the embodiment of FIG. 4, while FIGS. 5(b) and 6(b) are corresponding side views. Reference numerals and 60 respectively indicate the mica supports with apertures; 61 and 61' therein which are shaped for receiving and locking the compressible ears therein. Compressible ears 62 and 62' extend from the

side elements

63 and 63 which are attached to main elements 64 and 64' of the shield members.

As shown, the compressible cars 62 can be in the form of triangularly-shaped louvers or tabs struck out from the flange 63 of the shield 64. The lower 62 is adapted, on being passed through the narrow portion of slot 61, to be compressed slightly, and upon entering the wider part of the slot 61, to expand and be locked securely therein.

In the embodiment of FIGS. 6(a) and 6(b), the compressible tabs 62' can be formed from a double-thickness stock of sheet material forming the flange 63' of the shield 64'. In this case reversedly-fiared compressible portions can be formed, which on being passed through the narrow portion of slot 61 are compressed and thereafter expand into the wider portion of the slot 61 to lock the shield 64 and associated device in place.

Although the invention and its operation has been described with reference to specific embodiments, it is intended that the invention is not limited to the particular details shown and described which may be varied Without departing from the spirit and scope of the invention and the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. The method of assembling an electron tube which includes a plurality of electron discharge devices comprising the steps of securing a connector member having ears on portions thereof which extend outwardly to a first segment-shaped insulating member of a first electron discharge device; hooking said ears in slots provided in a second segment-shaped insulating member of a second electron discharge device; rotating said second electron discharge device relative to said first electron discharge device to juxtapose said electron discharge devices and said insulating members, with said insulating members complementing each other to form a circular periphery; securing another portion of said first electron discharge device to said second electron discharge device to anchor said device together in the juxtaposed position; and inserting the juxtaposed devices into an envelope with the circular periphery of the combined insulating members contacting the interior wall of the envelope.

2. The method of assembling an electron tube which includes a plurality of electron discharge devices in a single envelope comprising forming first and second pairs of insulative supports into complementary shapes which combine to define a circular periphery corresponding to the shape of the interior wall of the envelope; forming apertures in said pairs of insulative supports for receiv ing and engaging elements of a first and second electron discharge device; mounting the elements of the first elec tron discharge device in the apertures formed in said first pair of insulative supports with connector means having a pair of cars thereon extending outwardly from said insulative supports to provide the first electron discharge device; mounting the elements of the second electron discharge device in apertures formed in a second pair of insulative supports to provide the second electron discharge device, hooking the pair of ears associated with the first electron discharge device into apertures formed in one of the insulative supports of the second electron discharge device; rotating said second electron discharge device relative to said first electron discharge device to juxtapose the devices and combine said pairs of insulative supports so as to define a circular periphery corresponding the shape of the interior wall of the envelope; anchoring said first and second electron discharge devices together in said juxtaposed relation to provide a mount assembly; and inserting said mount assembly into the envelope with the periphery of the combined supports contacting the interior wall of the envelope.

References Cited by the Examiner UNITED STATES PATENTS 863,536 8/1907 Hudson 220-234 2,232,220 2/1941 Feindel 3l3-6 2,546,590 3/1951 Ferrel 22031 2,746,081 5/ 1956 Gershen 220-31 2,921,209 1/1960 Bloom 313--6 3,131,826 5/1964 Wiklund 22023.4

JOHN F. CAMPBELL, Primary Examiner.

W. I. BROOKS, Assistant Examiner.