US2837696A - Laminated magnetron constructions - Google Patents

Description

June 3, 1958 A A. 1:. LA RUE LAMINATED MAGNETRON CONSTRUCTIONS 2 Sheets-Sheet 1 Filed Oct. 7. 1954 INVENTOR I ALBERT D. LARuE v T NEV June 3, 1958 A. D. LA RUE 2,837,696

LAMINATED MAGNETRON CONSTRUCTIONS Filed Oct. 7, 1954' I I 2 Sheets-Sheet 2 @Q m A v LEE/2T A U5 @6 By g y TTORNE V United States Patent '0 M LAMINATED MAGNETRON CONSTRUCTIONS Albert D. La l lue, Lexington, Mass., assignor to Raytheon Manufacturing Company, Waltham, Masa, a corporation of Delaware Application October 7, 1954, Serial No. 460,982

4 Claims. (Cl. 315-39.75)

This invention relates to an electron discharge device, and more particularly to electron discharge devices of the so-called magnetron type, which are adapted to generate electrical oscillations having a wave length of the order of a few centimeters or less.

Devices of this kind are intended to oscillate in a predetermined primary mode so as to generate a predetermined frequency, and usually comprise a plurality of arms called vanes, each pair of which bound a cavity and form an inductance. Each pair of vanes also has juxtapositioned surfaces forming a capacitance. Difiiculty has been encountered in that additional modes of oscillations have occurred, these being related to the multitank circuit system employed. These additional modes are, in effect, spurious oscillations, consuming energy and reducing the efficiency of the device. It has been found that by connecting alternate arms in a manner called strapping, the spurious oscillations are greatly reduced. As heretofore constructed, the means for reducing the spurious oscillations involved certain difiicult, as well as expensive, machining operations. This was due to the fact that, after the anode was assembled, an annular groove would be machined in the anode and then pre- This operation was anode construction of magnetrons particularly with respect to the laminated type of construction.

An object of the invention is to provide an improved anode construction in which the anode straps are prestamped as part of the laminations used in constructing the anode. This type of construction allows the straps to be placed in any position in the anode. There is an additional advantage in that both straps can have the same diameter and be symmetrical in design.

A further object of this invention is to include an opening in the laminated sections of the anode to form openings for the passage of a cooling medium.

The foregoing and other objects and features of the 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: i

Fig. 1 is a top view of an embodiment of a magnetron constructed in accordance with this invention;

Fig. 2 is a section taken along line 22 of Fig. 1;

Fig. 3 is a section taken along line 33 of Fig. 1;

Fig. 4 is a section taken along line 44 of Fig. 1;

Fig. 5 is a series of diagrams illustrating how the straps are constructed as part of the laminations;

Fig. 6 is a development drawing of the anode illustrated in Fig. 1; and

Fig. 7 is a sectional view of another embodiment of a magnetron constructed in accordance with this invention.

Referring now to Figs. 1, 2, 3 and 4, there is shown for the purpose of illustration only an embodiment of a magnetron wherein the laminated anode has been constructed using the center-strap design. The magnetron illustrated 2,837,696 Fatented June 3, 1958 in Fig. 1 consists of an envelope structure 10 which formsthe anode 11 of the magnetron. Under normal operation the oscillations are generated at a frequency which is determined by the geometry of the vanes 12 and the cavity resonators 13 located therebetween. These oscillations are picked up by a coupling device 14 which is adapted to feed any suitable utilizing device.-

As pointed out above, heretofore the straps for a laminated anode had to be pre-assernbled and the anode carefully machined or routed where the straps were to be placed. After'placing the straps in position it was then necessary to solder the straps to the proper vanes. At very best this operation could be used for straps placed on the end section of the anode. It has long been recognized that a center-strapped anode has more advantages over end-strapped anodes, in that the straps could be electrically balanced, symmetrical, and have reduced coupling between the strap and the end section of the anode. Heretofore, a symmetrical center strapped anode could not be built for a completely laminated anode.

In accordance with the present invention the anode 11 is constructed of all stamped parts. Anode 11 is made up of a plurality of flat stamped laminations 15, 16, 17,

18, 19 and 20 preferably constructed of high conductivity copper and in the form as illustrated in Fig. 5.

Each lamination is formed with a center opening 21 and a plurality of radial slots 22 each terminating in the center opening 21. The interconnections between alternate vanes are made substantially along the central portion of the anode faces by means of conducting straps 23 and 24. As illustrated in Fig. 6, strap 23 electrically interconnects vanes 25, 26, 27, and 28 while the intervening vanes 29, 30, 31 and 32 have their faces provided with a slot through which strap 23 passes freely so as to avoid electrical contact with said intervening vanes. Likewise the strap 24 is electrically connected to the vanes 29, 30, 31 and 32, while the faces of vanes 25, 26, 27 and 28 are provided with slots which permit the strap 24 to pass through without coming into electrical contact with the intervening vane faces. These interconnections on straps between alternate vanes substantially eliminate the tendency for transverse spurious modes of oscillations to occur. The complete method of strapping a full 8-vane anode is illustrated in Fig. 6. It is well known that such strapping not only substantially eliminates spurious transverse modes but will also substantially elimihate the spurious longitudinal modes.

Fig. 3 represents a cross-sectional view of vanes 29, 30, 31 and 32 and Fig. 4 represents a cross-sectional view of vanes 25, 26, 27 and 28. The anode 11 is built up of the basic lamina sections 15, 16, 17, 18, 19 and 20 stacked so as to attain the type of strapping desired. In order to build up the cross-sectional view illustrated in Figs.

3 and 4, it is necessary to use the following stampings in assembling from top to bottom:

Lamination 15 is a circular strapping having a large central hole and is used for building up the end section of the anode. Laminations 17, 18, 19, and 20 have identical holes 33 punched near the peripheries of the laminations so as to provide a passage 34 in the comnation 18 has every other vane shortened a given amount in order to provide clearance in a radial direction for straps 23 and 24. Lamination 19 contains the straps joining every other vane. The vanes not so joined are cut back a given amount to provide clearance in a radial direction for the straps 23 and 24. Lamination 20 has all the vanes cut back a given amount to provide clearance in a vertical direction between straps 23 and 24. It is apparent in building up an anode section that lamina 18 and 19 are used twice. Lamination 19 is used twice in order to obtain both straps 23 and 24 and lamination 18 is used to obtain the necessary clearance between the straps and the vanes. To obtain both straps it is only necessary to oiiset lamination 19 by one vanes position. It is for this reason that Fig. does not have the vanes numbered. After assembly of the anode section, a facing 35 is applied to all the vanes in order to protect the strapping from electron bombardment. Facing 35 is preferably constructed from a silver utectic material so as to form a silver braze covering the vanes as illustrated.

It will be apparent to those skilled in the art that the present method of having the straps constructed as part of the lamination is adaptable to be used for any strapping design incorporated in laminated anode construction.

Of course it is to be understood that this invention is not limited to the particular details as described above as many equivalents will suggest themselves to those skilled in the art. For example, Fig. 7 illustrates an unsymmetrical method of double strapping a laminated anode wherein both straps are placed at one end of the anode. It is entirely conceivable that a single strap may be placed at each end of the anode. These and many other ways of strapping an anode by means of prestamped laminations will suggest themselves to those men skilled in the 'art. In each instance, by utilizing the principles of the invention as enunciated herein, it will be possible to construct strapped anodes of any desired form and shape and thus remove spurious modes of oscillations in a more economical manner than has been possible to date.

What is claimed is:

1. An electron discharge device comprising a laminated anode constructed of a plurality of individual laminations, said anode having a plurality of vanes of substantial length and adapted to have oscillations set up therein, and a facing material for each vane thereby protecting said laminations from electron bombardment.

2. Electron discharge device comprising a laminating anode constructed from a plurality of individual laminations, said anode having a plurality of vanes of substantial length and adapted to having oscillations set up therein, interconnecting straps punched out of the same laminations used to assemble the anode for electrically connecting alternate vanes, and a facing material for each vane electrically interconnecting laminations forming said vane.

3. An electron discharge device comprising a laminated anode constructed from a plurality of individual laminations, said anode having a plurality of vanes of substantial length and adapted to have oscillations set up therein, strapping means electrically interconnecting alternate vanes, means for facing each vane thereby pro tecting said strapping means and said laminations from electron bombardment, and a passage located in said anode for cooling said anode, said strapping means and said cooling passage constructed as part of the same lamination used to assemble the anode.

4. An electron discharge device comprising a laminated anode constructed from a plurality of individual laminations, said anode having a plurality of vanes of substantial length and adapted to have oscillations set up therein, interconnecting straps punched out of the same laminations used to assemble the anode for electrically connecting alternate vanes, a facing material for each vane electrically interconnecting the laminations forming said vane, and a cooling passage punched out of the same lamination used to assemble the anode.

References Cited in the file of this patent UNITED STATES PATENTS 2,444,080 Williams June 29, 1948 2,477,122 Garner July 26, 1949 2,547,503 Smith Apr. 3, 1951 2,583,793 Nelson Ian. 29, 1952

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