US2400122A - Manufacture of miniature thermionic devices - Google Patents

Description

May 14, 1946. v F. R. KEW ET AL 2,400,122

MANUFACTURE OF MINIATURE THERMIONIC DEVICES Fil ed June 25, 1943 2 Sheets-Sheet 1 7 IN VENTORS jfi A/v/r f2 KEW.

BY 2 e/bSEPH JBA/VNOM May 14, 1946. F. R. KEW ET AL 2,400,122

MANUFACTURE OF MINIATURE THERMIQNIC DEVICES Filed June 25, 1945 2 Sheets-Sheet 2 A TTORNE Y5 Patented May 14, 1946 MANUFACTURE OF MINIATURE THERMIONIC DEVICES Frank R. Kew, Bloomfield, and Joseph James Bannon, J r., North Arlington, N. .L, assignors to Tung-Sol Lamp Works,Inc., Newark, N. J., a

corporation of Delaware Application June 25, 1943, Serial No. 492,218

' 15 Claims. (Cl.'2 50 -27.5)

This invention relates to the manufacture of thermionic devices.

In the manufacture of thermionic devices, and particularly miniature devices, the assembly of the elements is usually a tedious operation requiring skilled labor and involving large expense and an unduly'large percentage of rejects. For example, one of such tedious operations is the assembly of direct emission filaments for miniature mounts, which are made of extremely small wire and are required to be inserted into and accurately positioned in the miniature grids.

One object of the'invention is a novel and improved method of assembly of these small direct emission filaments in miniature mounts.

A further object of the invention is a novel means and apparatus for facilitating such assembly.

Further objects of the invention'will hereinafter appear.

For a better understanding of the invention reference may be had to the accompanying drawings wherein:

Fig. 1 isa side view partly in section of a novel apparatus embodying the invention;

Fig. 2 is a view of the same taken at right angles to Fig. 1;

Fig. 3 is a view taken on the line 3-3 of Fig. 1;

Fig. 3a is a perspective view illustrating a modification of a part of the apparatus;

Fig. 4 is a sectional view of a miniature mount to which the invention is applicable;

Fig. 5 is a view at right angles to Fig. 4;

Fig. 6 is a sectional view along the lines 6-6 of Fig. 4; r

Fig. 7 is a sectional view along the line 1-1 of Fig. 4; and

Fig. 8 is an enlarged perspective view of a part of the apparatus.

We have illustrated the invention as applied.

to the assembly of direct emission filaments in miniature mounts, but it is understood that this is for illustrative'purposes only and that certain features of the invention are of more general application.

This mount is shown on an enlarged scale in Figs. 4-8 for purposes of illustration. It comprises concentric cylindrical plates I and 2, with mica or other insulating discs 3 and 4 fastened at the bottom and top of these plates respectively and holding them in concentric relation. The particular means of fastening is omitted for convenience in illustration. The device comprises a -multi grid structure, there being three such grids -5, 6 and l. The grid 5 is carried by the posts or.

cost is unduly large.

wires 8, the grid 6 by the'wires 9, and the grid 1 by the wires to. These wires project through openings formed in the discs 3 and 4 and are disposed inthe same plane. The grid structures are oval-shaped-in cross-section and are concentric with each other, though the cross-section of the outer grid 5 more nearly approaches a circle.

In addition to the elements above described the device comprises a direct emission filament H :disposed within the innergrid I. These filaments H are so fine and small that they can be assembled with only the greatest care and skill according to the conventional practices and even with the most careful and skillful operations the reject percentage is quite large and the labor Our invention resides in an improved method and means for introducing these very fine filaments H into and through the 0 very small inner grids I. 2 1

The loading means comprises a funnel-shaped member I5 open at the top l6 for the reception -of the fine emission filaments H. The outlet for the funnel is a small cylindrical bore H.

The funnel member I5 is provided with a slot l8 extending throughout its length from top to bottom and parallel to the funnel axis, this slot extending all the way through the wall of the member to the opening or funnel-shaped chamber in the center. The slot walls are flared at their upper ;ends as'indicated at l8 for a purpose hereinafter described.

At the base of the funnel there is attached an aligning or locating element 20 which maybe formed integrally with or as a separate. element from but fastened to the funnel, and the cylindrical bore ll continues through this element. This element is constructed so as to center the funnel with the cylindrical bore I! over a centrally disposed V-shaped opening 4' in the top :mica disc 4. The slot 18 is continued through this element. 20, so as to allow the filament to be released from the loading device. 'The under side of the, element is a plane surfacedisposed at "right angles to the'axis of the funnel and in the assembling or loading operation the element 20 rests directly uponthe top mica or shield disc 4. The element 20'is provided on its front side with locating parts 2| against which, parallel to the axis of the funnel, the projecting ends of the grid posts. OIWilBslU bear when the mount is in position :for loading. These parts 2| are provided with slight recesses or grooves for receiving the wires Ill and facilitating the alignment. The funnel member and the mount are aligned with the cylindrical, bore IT in alignment with the opening 4 and the interior of the grid 1 when the mount is held with its end against the underside of the loading device and the projecting wires II] in the grooves 22.

With the funnel member I5 and the locating element supported in any suitable manner as, for example, by bracket 25, the thermionic mount is held in the assembling position shown in Figs. 4-6 with the locating element 20 resting upon the disc 4 and against the projecting ends II] of the posts or wires carrying the grids. The grooves 22 which are formed in the aligning parts 2| of the element 20 facilitate the location and positioning by forming positive bearing surfaces. The element 20 may also be provided with a projection 23 extending between the projecting ends I6 of the grid posts or wires which also facilitates the location and positioning of the mounts against the funnel element. Preferably an auxiliary support 25', in the form of a V, is carried by the bracket 25, against which the body of the mount rests during the loading.

The funnel element I5 is preferably supported at an angle of 115" from the horizontal plane inclined to the left of the loading operator or perpendicular to the horizontal plane depending upon the type of tube construction. In the particular embodiment here shown, the funnel element is supported at an angle of approximately 115 to the horizontal. of an angle supporting bracket member 26 fastened as indicated-at 21 to a supporting frame 28. The support '25 for the funnel I5 is formed of a twisted strip of metal and the end is attached to the upper-end of the angle member 26 by a screw 29. Thus the funnel I5 is supported with the plane of the slot I8 in the plane of the supporting member '26 and the funnel may be adjusted to any desired position in that plane by adjusting the supporting arm 25 with respect to the fixed supporting arm 26.

The loading or assembling operation is facilitated by imparting vibrations to the funnel I5 during the loading operation and in the particular embodiment shown in Fig. 1 this vibration is imparted to the funnel I5 by means of a vibrating means which imparts the vibration to the angle support 26. The yibrating means is carried by a bracket 3| mounted upon the fioor or frame 28 and comprises an element 32 which directly acts upon the support 26 to vibrate it and impart to the loading unit I5 vibrations with sufficient amplitudeand frequency to accelerate the loading and assembling of the filaments II during their passage through the loading device and into and through the grid 1. This vibrating means '30 is diagrammatically illustrated for convenience in'illustration and it comprises generally any electrical or other suitable means for imparting a vibrating motion to the element 32 and hence to the support 26. In the modification of Fig.3a the vibrating means comprises electrical coils 30 mounted on a plate 26' carried at the upper end of 26 and a hammer element 32 actuated by the coils. It will be understood that in Fig. 3a, the plates 26, the brace 25' and the funnel I5 are rigidly connected together in any suitable manner, so that vibrations of the plate 26' resulting from the blows of the hammer 32 are transmitted to the funnel l5. For convenience of illustration the means connecting the elements 26', 15 and 25 are not shown in the diagrammatic drawings.

The fine emission'filaments II are each provided with a supporting arm and electrical con- This is effected by means nection 35 at one end and each is loaded at its other end with a heavy terminal or weight 36.

The method in operation of assembling the emission filaments I I are as follows:

A mount as shown in Figs, 4-6 is held against the funnel or the element 20 with the cylindrical bore I11 properly aligned with respect to the opening 4' of the disc 4. This may be done by hand. With the mount thus held firmly against the loading device an emission filament II is introduced into the funnel whereupon the vibrating means 30 is set into operation to impart the desired vibration to the loading device. This vibration causes the filament II quickly to feed itself downwardly into the mount, the loaded end 36 falling by gravity during the shaking or vibrating operation through the opening 4 in the insulator disc 4 and thence downwardly through the interior of the grid 1. The lower disc 3 is provided with an opening 3' in alignment with the opening 4' in'the upper disc and the loaded or weighted end 36 of the filament quickly finds its way through this opening '3', the vibration step'facilitating this operation. The right angle electrical connection 35 arrests the downward movement of the filament when it reaches the disc 4. This connection 35 easily finds the slot I8 through the flared opening at I8 and follows the slot on down until it rests on the end of the mount.

The grid 1 is provided with a filament tensioning member 40 which is in the form of an angle piece welded to one of the posts or wires If] intermediate its ends. It projects inwardly and laterally of the grid and is then turned to form a bend 40' crosswise of the plane ofthe grid wires, When the filament II is finally fastened at its ends the filament assumes some such position as that indicated in Fig. 7, with the member 40 engaging and tensioning the filament against vibration. In the assembling operation the mount is inclined to the left, looking at Fig. 4, so that the weighted end 36 of the filament tends to follow the left hand wire Ill downwardly as a guide past the member 40. The vibration of the loading device and the mount during the assembly operation and the inclination cause the loaded end 36 to dance past this member 40 which in the conventional practice causes so much difliculty in the loading operation.

With the filament II introduced through the grid 1 as shown in Fig. 4, the electrical connections may be made in any suitable manner, and these connections are omitted from the drawings for convenience in illustration. The parts'35 and 36 serve as means for connecting the filament in circuit. Only the mount comprising the discs 3 and 4 and intermediate parts is shown, but it is understood that the completed tube would include an envelope, a seal and the desired electrical connections. The mount of the particular radio tube shown comprises aglass button 42 (Fig. 3a) which forms a ready means by which the mount may be held against the loading device with the fingers.

We claim:

l. The method of loading small direct emission filaments in miniature thermionic devices comprising the steps of aligning the thermionic mounts with and holding them firmly against a loading device, feedingthe filaments to said loading device and applying a vibrating force to said loading device during the loading operation.

2. The method of loading'direct emission filaments in mounts 'for thermionic devices comprising the steps of aligning the mounts with funnel-shaped loading device having an elongated slot on one side thereof and holding the mounts firmly against the loading device with the funnel device in line with miniature grid elements of the mounts, feeding endwise to said funnel filaments having their lower ends loaded and angular electrical connections fastened to their upper ends, said funnel-shaped device having a slot on one side for the accommodation of said electrical connections, and applying a vibrating force to said funnel-shaped device and the mounts after the filaments are fed to the funnel device.

3. The method of loading direct emission filaments in mounts for thermionic devices comprising the steps of aligning the mounts with a funnel-shaped loading device having an elongated slot on one side thereof and holding the mounts firmly against the loading device with the latter in line with miniature grid elements of the mounts, feeding endwise to said funnel filaments having their lower ends weighted and electrical connections fastened to their upper ends, said funnel-shaped device having an elongated slot on one side for the accommodation of said electrical connections, and applying a vibrating force to said funnel-shaped device and the mounts after the filaments are fed to the funnel device, said funnel device being supported with its axis inclined to the vertical.

4. The method of loading direct emission filaments in mounts for thermionic devices comprising the steps of aligning the mounts with a funnel-shaped loading device having a slot on one side thereof and holding the mounts firmly against the loadingdevice with the latter in line with miniature grid elements of the mounts, feeding endwise to said funnel filaments having their lower ends weighted and angular connections fastened to their upper ends, said funnelshaped device having a slot on one side for the accommodation of said electrical connections, and applying a vibrating force to said funnel-shaped device and the mounts after the filaments are fed to the funnel device, said funnel device being supported with its axis inclined to the vertical and away from tensioning members disposed intermediate the ends of the grids with the grid wires guiding the filaments to the desired locations within the grids.

5. The method of assembling filaments in miniature thermionic devices which comprises the steps of feeding a filament through an orifice in the mount assembly to one end of the miniature grid within which it is to be positioned and applying to said thermionic device a vibrating force to facilitate the introduction of the filament into the grid.

6. The method of assembling direct emission filaments in mounts for thermionic devices which comprises the steps of holding the mounts'inclined to the vertical, feeding the filaments endwise into orifices in the upper ends of the inclined mounts and applying a vibrating force to the mounts.

7. The method of assembling filamentary elements in miniature thermionic mounts which comprises the steps of introducing an end of an element into an orifice in the end of a mount and. applying a vibrating force to the mount to cause the filament to feed itself into the mount.

8. The method of assembling filamentary elements into the grid parts of miniature thermionic mounts which comprises the steps of loading the filamentar elements with weights at one end, feeding the elements endwise to the grid elements with the weighted ends down, and causing the weighted filamentary elements to feed them selves downwardly into the grid parts by the application of high frequency vibrations.

9. The method of assembling filamentary elementsinto the grid parts of miniature thermionic mounts which comprises the steps of loading the filamentary elements with weights at one end, feeding the elements endwise to the grid elements with the weighted ends down, and inclining said grid elements to the vertical to cause the elements to follow a grid support wire as a guide.

10. The method of assembling filamentary elements into miniature thermionic mounts which comprises the steps of fixedly supporting a loading device, successively holding the mounts against the loading device in alignment therewith to receive the filaments, inserting the filaments into the loading device and after filaments are fed to the loading device applying a vibrating force to said loading device.

11. A means for facilitating the assembly of filamentary elements into miniature thermionic mounts comprising a loading device with which the mounts are to be aligned for the reception of the filamentary elements and means for imparting to said loading device vibrations of the desired frequency and amplitude.

l2..A means for facilitating the assembly of filamentary elements into miniature thermionic mounts comprising a loading device with which the mounts are to be aligned for the reception of the filamentary elements and means for imparting to said loading device vibrations of the desired frequency and amplitude, said loading device being supported at an angle to the vertical.

13. A means for facilitating the assembly of filamentary elements into miniature thermionic mounts comprising a loading device with which the mounts are to be aligned for the reception of the filamentary elements and means for imparting to said loading device vibrations of the desired frequency and amplitude, said loading device having an interior which is funnel-shaped at its lower end.

14. A means for facilitating the assembly of filamentary elements into miniature thermionic mounts comprising a loading device with which the mounts are to be aligned for the reception of the filamentary elements and means for imparting to said loading device vibrations of the desired frequency and amplitude, said loading device having an interior which is funnel-shaped at its lower end and having a longitudinal slot in the wall thereof.

15. A means for facilitating the assembly of filamentary elements into miniature thermionic mounts comprising a loading device with which the mounts are to be aligned for the reception of the filamentary elements and means for imparting to said loading device vibrations of the desired frequency and amplitude, said loading device comprising an upper part for the reception of the filamentary elements and a lower part having an aligning and locating part against which the thermionic devices are held during the loading operation.

FRANK R. KEW. JOSEPH JAMES BANNON, JR.

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