US2445766A

US2445766A - Apparatus for assembling parts of electron discharge devices

Info

Publication number: US2445766A
Application number: US528442A
Authority: US
Inventors: Paimer P Derby; Warren M Robertson
Original assignee: Raytheon Manufacturing Co
Current assignee: Raytheon Co
Priority date: 1944-03-28
Filing date: 1944-03-28
Publication date: 1948-07-27
Anticipated expiration: 1965-07-27

Description

July 27, 1948.

P. P. DERBY ET 2,445,766

TUS FOR ASSEMBLING PARTS ECTRON DISCHARGE DEVICES APPARA OF EL Filed March 28. 1944 A 2 Sheets-Sheet 1 July 27, 1948.

Filed March 28. 1944 P. P. DERBY Erm. 2,445,766 APPARATUS FOR A EHBLING PARTS OF ELECTRON DI ARGE DEVICES 2 Sheets-Shadi. 2

i@ if Patented July 27,A 1948 APPARATUS FR ASSEMBLING PARTS F ELECTRON DISCHARGE DEVICES Palmer P.Derby, Boston, and Warren M. Robertson, Wakefield, Mass., assignors to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application March 28, 1944, Serial No. 528,442

4` claims. (ci. 113-99) This invention relates to apparatus for manufacturing the anode structure of hyper and ultra high ifrequency oscillation tubes of the magnetron type.

In tubes of the type. to which the invention relates, the anode structure comprises a metallic block having a cylindrical cavity and a plurality o'f substantially radially-disposed anode arms projecting inwardly from the wall of said cavity. The space between each pair of arms or plates constitutes a cavity resonator. The frequency of the oscillations produced by such a device depends upon the geometrical coniiguration of the resonator, and it is important that the anode plates be accurately spaced so that the cavity resonators will be accurately matched. The efficiency ofthe device depends in large part upon such accurate. matching of the cavity resonators.

Heretofore difficulties have been encountered in constructing anode structures of the above type and the art has resorted to relatively complicated and expensive arrangements requiring skilled workmanship to insure the required accuracy. In the copending application of William C. Brown, Serial No. 522,194, filed February 10, 1944, now Patent No. 2,433,339, issued Dec. 30, 1947, there is disclosed a method and apparatus which facilitate the construction of such devices and increase the accuracywith which they may be constructed.

It is an object of the present invention to iurther improve the accuracy of construction and facilitate the manufacture of such devices, so that the same may be manufactured by relatively unskilled labor with a high degree of accuracy.

Devices of the type to which the invention relates may oscillate not only at 'the desired frequency determined by. the cavity resonators dened by each pair of adjacent anodev plates but also as to generate spurious, undesired oscillations due to oscillating circuits provided by nonadjacent anode plates. It has heretofore been Ifound that these spurious undesired oscillations may be minimized byinterconnecting the inner :ends of alternate anode arms or plates by various strapping` arrangements. Such strapping artion of such anode structures having a complete strapping arrangement without materially in- Y creasing the cost of manufacture or the labor and skill required as compared with unstrapped structures.

The foregoing and other objects and features ofthe invention will be made fully apparent to those skilled in the art from a consideration of the following detailed description taken in conjunction with the accompanying drawings in which:

Fig. 1` is a perspective view, with parts in section and parts broken away, of the novel apparatus of this invention; i

Fig. 2 is a section taken on line 2-2 of Fig 1;

ig. 3 shows, on a reduced scale, an exploded perspective view of the jig structure;

Fig. 4 is a vertical sectionthrough the jig structure; and

Figs. 5 and 6 show, on an enlarged scale, details of the anode structure.

Referring to the drawings, the anode structure which is to be constructed in accordance with the invention comprises an anode block I of highly conductive material, such as copper. The block l has a central opening extending therethrough providing a cylindrical cavity 2, which cavity has an annular projection 3 intermediate the ends thereofl from which projection a plurality of anode plates 4 and liextend inwardly toward the axis of the cylindrical cavity. The outer edges of the

plates

4 and 4 are secured to the face of the annulaiprojection 3 by soldering and the inner edges thereof form a plurality of anode faces adapted to cooperate with a thermionic cathode to be positioned centrally of the cavity fin the free space adjacent the inner ends of the plates- 4 and 4. As is well understood in the art, an even number of plates 4 and 4' are provided and the space between each pair of adjacent plates constitutes a resonant cavity.

At points adjacent their inner edges, alternate anode plates 4 are electrically connected together at the upper ends thereof by means of an outer `strap 5, while the intervening plates 4 are electrically connected by an inner strap 6. At the lower ends of the anode plates, the plates 4' are connected together by an outer strap 5 and the plates 4 are connected by an inner strap 6'.. -It will be seen'that the strapping arrangement at the lower end of each anode plate is the reverse of the strapping arrangementl at the top of the plate; in other words, where the plate is connected t0 the outer strap 5 at its upper end, the lower end is connected to the inner strap B and vice-versa.

In order that the straps 5-6l and 5'-6' may be alternately connected to the anode plates or lpass freely adjacent thereto, as required by the above construction, I provide a notch l in. one

the annular projection 3. Assuming that the plateisl to be one of the anode arms 4, it is inserted with the notch 8 at the lower end thereof,

- and in its lowermost position the plate will connotch 8 having-,astepped portion Bf'gspaceld to accommodate the

inner straps

6 or 6. and the width and depth of this notch is such that the strap or 5' may pass freely therethrough without contacting the plate. The plates-4 and 4' are identical in construction, but in assembly the position of the notches 'I and 8 is reversed. the.

plates 4 being positioned with the notch 1 at the upper end, while the plates 4' .are positioned with the notch 8 at the upper end.

In order to construct the anode arrangement as described above, I provide a jig 9 comprising a base I0 from which projects a support and positioning member II. The support II has a lower cylindrical portion I2 adapted to flt in a suitable bore in the base I0 and to be held upright thereby.

Above the cylindrical portion I2 is an intermediate fiange I3 upon which the lower end of the anode block I is adapted to rest and to be centered relative tothe jig 9 by a shouldered portion I4 projecting into the opening 2 to a point y below the annular projection 3. An upper cylindrical portion I5 having a plurality of slots I6, extending longitudinally thereof, projects upwardly from the shouldered portion I4, concentric with the opening 2, for such a distance that the upper end of the cylindrical portion I5 will project above the annular projection 3 of the anode block I when the latter is positioned on the jig. A central opening I1 extends through the support II having a lesser diameter than the internal diameter of the cylindrical portion I5, leaving a shoulder I8 between said opening and the internal surface of the cylindrical portion I5, A mandrel I9 extends through the' opening I1 and through the slotted cylindrical portion I5 to a -point above the upper end of said cylindrical portion, and is provided with splines 20 extending from the upper end thereof, at least as far as the shouldered portion I8. The outer diameter of the mandrel I9 is such that it makes a sliding fit with the opening I1, and the internal diameter of the

straps

6 and 6 is substantiallir the same as the diameter of said mandrel, so that these straps may be slipped on the mandrel and centered thereby. The outer'diameter of the

straps

5 and 5 is approximately equal to the internal diameter of the slotted cylindrical portion I5 so that these straps make a sliding fit with the interior surface 'of said cylindrical portion and may be -centered thereby. The depth of the splines 20 is made equal to the. distance D between the inner edges of the plates 4 and 4' and thestepped portion 8 of the notches 8.

In the manufacture of anode structures of the type described in the foregoing by means of my novel apparatus, the lower straps 5' and 8', which are of conductive material, such as copper, and preferably coated with solder for reasons which will hereafter more fully appear, are rst inserted in the jig between the slotted cylindrical portion I5 and the mandrelml9 so that they rest on the internal shoulder I8 with the strap 5 centered by the interior surface of the cylindrical portion I5 and the strap-6 centered by the mandrel I9. One of the

anode plates

4 or 4 is inserted into the opening 2, being guided by one of the slots I5 with its inner edge in one of the splines 20 and its outer edge in contact with the surface of tact the strap B' at the stepped portion 8' of the notch 8 and will be free and clear of the strap v 5,' as shown in Fig. 5.

It will be understood that the number of slots I8 in the cylindrical portion I5 of the support II will correspondl to the number of

anode plates

4 and 4 desired in the anode structure, and a corresponding number of splines 20 will be provided inthe mandrel I9, and therefore if one of the splines 20 is aligned with one of the slots I5,

`each of the other splines will be aligned with a corresponding slot I5. Accordingly, the next adjacent plate may be inserted in the next adjacent spline and'will be guided into position by the corresponding slot I5. This plate is inserted with the notch 1 at the lower end thereof and the notch 8 at the upper end to provide one of the plates 4. In its lowermost position this plate will contact the strap 5' at the stepped portion 'I' of the notch 1 and will be free and clear of the strap 6', as shown in Fig. 6.

, The next succeeding plate will be inserted with lthe notch 8 at the lower end thereof to provide one of the plates 4, and the succeeding plates will be inserted with the notches 'I and 8 alternately in the lowermost position.

In the instance shown, twelve of the

plates

4 and 4 are provided, and it will be understood that any even number of plates may be used. When all 0f the plates 4 and 4' have been positioned in the jig, the strap 6 is inserted, being guided into position by the mandrel I9, and it 'will be seen that this strap will rest upon the stepped portion 8' of the notches inthe plates 4', and its upper surface willbe flush with the upper edge of these plates. The strap 5 is inserted, being guided into position by the interior surface of the cylindrical portion I5, and it will be seen that this strap will rest on the stepped portion I of the notches 'I in each Aof the plates 4, the distance L between the inner edge of the plates and outer edge of the stepped portion 1' of the notch 'I being equal to the distance from the base of any spline 20 to the interior surface of the cylindrical portion I5.

The straps 5 an 6 are of conductive material and are preferably coated with solder, the same as straps 5' and 6'. The preferred solder for this purpose is an eutectic alloy of silver and copper.

After the plates 4 and 4' and the

straps

5, 5' and 6, 6 have been assembled in the jig, as described in the foregoing, a weight 2l, having an annular boss 22 projecting centrally therefrom, is placed on the jig to'holdl the parts in position for soldering.1 For this purpose the annular boss 22 has an internal diameter corresponding to the outer diameter of 'the mandrel I9 and an external diameter corresponding to the internal diameter of the slotted cylindrical portion I5, so that when the weight is positioned on the jig the boss 22 will project into the annular space between the mandrel I9 and the cylindrical portion I5, and bear at its lower end on the

straps

5 and 6. The

straps

5 and 6 are tamped into place by the boss and are held in the desired position in the stepped portions 'I' -and 8', respectively, of the notches I and 8 with the upper surfaces of the straps flush with the upper edges of the

plates

4 and 4. The lower straps 5' and anarco 6' are similarly maintained in position by the l shoulder Il. n

The parts of the assembly may now be secured together?= bysoldering. and -it is for this purpose I prefer that each of the straps I, and 6, 6' be provided with a thin coating of solder, preferably an eutectic alloy of lsilver and copper.

The outer edges of the plates 4 and 4' may be provided with a thin coating of solder for securing the plates to the annular projection l of the block i, or preferably a thin ring of the solder may be placed at .the upper outer ends of the plates 4 and I' adjacent the cylindrical surface of the annular projection 3. `The entire assembly may then be placed in a furnace having a non-oxidizing atmosphere and heated to a temperature suiilcient to melt the solder. Ihe solder secures the straps l, 'I' and 6, 8' to the plates l and 4' at the points ot contact in the stepped portions l' .and l of the notches 'l and 8, and i the outer edges of theV plates are secured to the cylindrical surface of the projection 3. Where a ring of solder is provided adjacent the upper outer ends of the plates, as described, it is found that the solder onl melting tends to flow down'- wardly along the lines of contact between the cylindrical surface and theedges of the plates and iiil the interstices therebetween.

' 2. An apparatus for assembling the component' directly opposite, in register with, and radially In order to prevent the solder from uniting any parts of the anode assembly to the jig, all parts of the latter are provided with surfaces to which the solder does not fuse. Preferably all parts of the jig arelmade of `or surfaced with stainless steel and the surfaces oxidized. The solder does not unite with such a surface, and after baking the completed anode assembly may be readily removed from the jig.

It will be seen that the iig structure above described and the procedure employed provide an eillcient means and method for rapidly and accurately assembling anode structures of the type described. The splines 20 and the slots I6 proyvide two spaced guides for each of the plates l, 4 and insure more accurate angular spacing of the plates while facilitating the ease with which they may be placed in position. The utilization of the inner surface of the cylindrical portion I5 as a guide and centering means for the

outer straps

5 and 5 and the outer circumference of the mandrel Is as a guide and centering means for the inner straps B and 6' insures that these straps will be accurately spaced and positioned without requiring great time, care or skill 'on the part of the operator.

While there has been herein described a preferred form of the invention, other embodiments thereof within the scope of the appended claims will be obvious to those skilled in the art from a consideration of the form shown.

What is claimed is:

1. An apparatus for assembling the component parts of the anode of an electron-discharge de-v vice comprising: a central member having a plurality of splines dening a plurality ofslots extending longitudinally thereof; and a cylindrical member concentric with said central member; said cylindrical member having a plurality of slots extending longitudinally thereof; the slots of said cylindrical member, throughout their major extent, being directly opposite, in register with. and radially spaced from the slots of said central member.

spaced from the slots in said central member.

3. An apparatus for assembling the component parts of thev anode of an electron-discharge device comprising: a base portion having a central cylindrical bore; a cylindrical member having a *sliding fit in-said cylindrical bore of said base portion; and a central member extending through said cylindrical member and having a plurality of splines defining a plurality of slots extending longitudinally thereof; said cylindrical member having an linternal wall spaced from said central member. and a plurality of slots extendinglongitudinally thereof; the slots of said cylindrical member, throughout their major extent, being directly opposite, in register with, and radially spaced from the slots in said central member.

4. An apparatus for assembling the component parts of the anode of an electron-discharge device of the type having a plurality of plates proj ecting radially from the interior wall of a cylindrical cavity, and having alternate plates electrically connected adjacent the inner ends thereof by an annular ring of conductive material, comprising: a central member having a plurality of splines defining a plurality of slots extending longitudinally thereof; and a cylindrical member concentric with and spaced from said central member, and having a plurality of slots extending longitudinally thereof; the slots of `said cylindrical member throughout their major extent, being directly opposite, in register with, and radially spaced from the slots in said central member; said central member having an outer 'diameter corresponding to the internal diameter of said ring.

PALMER P. DERBY. WARREN M. ROBERTSON.

REFERENCES CITED The following references are of record in the file of this patent:`

UNITED STATES PATENTS OTHER REFERENCES A skin Game in Metallurgy, scientinc Amer.. June 1941, pages 331-332.