US2714676A

US2714676A - Electron tube rigidizing means

Info

Publication number: US2714676A
Application number: US199438A
Authority: US
Inventors: Raymond R Machlett; Leferson Joseph
Original assignee: Machlett Laboratories Inc
Current assignee: Machlett Laboratories Inc
Priority date: 1950-12-06
Filing date: 1950-12-06
Publication date: 1955-08-02
Anticipated expiration: 1972-08-02

Description

1955 R. R. MACHLETT ET AL ELECTRON TUBE RIGIDIZING MEANS Filed Dec. 6, 1950 FIG. I

FIG. 2 1:

INVENTORS RAYMOND R. MACHLETT JOSEPH LEF SON W4.

ATTORNEY Patented. Aug. 2, 1955 2,714,676 ELECTRON TUBE RIGIDIZING MEANS Raymond R; Machlett, New Canaan ,.and Joseph Leferson, Springdale, Conn., assignors to Machlett Laboratories, Incorporated, Springdale, Conn., a corporation of (Torn necticut Application Decemberfi, 19-50, Serial No; 199,438 3 Claims. (Cl. 313-40) This invention. relates to means for increasing the rigidity of envelope portions of electron tubes. In particular this invention offersa means of increasing, the rigidity of. members; located at one: end of a coaxial electron tube. 1

The development of coaxial electron tube constructions has given, rise to many mechanical as well as electrical problems. Mechanical strength and rigidity requirements for envelope members often are determined by the type of handling which tubes must undergo. Where some portion of the envelope is bent: or flexed, it may impose stresses which cause work hardening and eventual breakage. The tendency for envelope parts to bend in coaxial tubes is most pronounced at the tube ends which are frequently-not reinforced.

In the past thisbending has presented an especially great problem in tube constructions employing a block anode at one end affixed near its active surface to a reentrant shell member which forms part of the vacuum envelope. This problem is common because reentrant shell structures are widely employed as thermal expansion compensation members-4. e., they are made of material whose expansion matches that of the surrounding adjacent anode terminal. There is an advantage, of course, in making the anode of a highly conducting material such as copper, in order to conduct the heat away from the active anode surface, but, were this block connected at the tubes base to the anode terminal, the expansion of the block would be greater than that of the terminal. The resulting reduction in inter-electrode spacing would cause a material change in the operating frequency. With a reentrant Kovar shell attached to a Kovar anode terminal at the tube base and the shell joined in turn at its other end to the copper block anode near its active surface, the problem of frequency shift is minimized, but the problem of rupture of the envelope due to bending is introduced.

The bending problem frequently arises at the tubes anode end because cooling fins which are rigidly attached to the anode block are often the only tube appendage external of the cavity and, hence, a convenient handle 5 for plugging a tube into or extricating it from a cavity. In accomplishing these operations it is difiicult to keep pressure wholly axial, but failure to do so produces radial pressure which tends to bend some portion of the envelope to which the anode is attached. Frequent flexing of the envelope in this manner will eventually result in rupture of thevacuum wall.

Thus it is the primary object of our invention to eliminate the opportunity for members coaxial with one another at the end of an electron tube to move with respect to one another. Accordingly, a rigid, essentially planar member is forced into contact with the coaxial members perpendicular to the axis thereof. The axial force upon this planar member prevents the radial displacement of any contacting coaxial member relative to any other contacting member. It is our object to thus prevent relative radial displacement of tube envelope parts by simple means which can be easily and cheaply made. It is. furthermore our object that this means be separate from the tube so that it may be salvaged in the event of tube failure.

It is an incidental object of our invention in the common case lnvolving a tubes anode end, where the anode.

terminal is the tubes largest, to provide a stop means.

for the contacting spring fingers of the cavity. Use of the preferred form of our invention will save the use of more complicated dies required for fabricating anode ter minals which incorporate such a stop.

Another incidental object of our invention is to lend rigidity to the terminal member itself. If this member has an edge at one end which is unattached or attached to another rather flexible member, it is possible that bend ing or flexing the terminal might. damage the envelope insulator. increasing the rigidity of the terminal member.

For a description of our invention reference ismade to the following drawings:

Fig. 1 shows the preferred form of our rigidizing means whereon is employed tubular flange means in a bottom View elevation.

Fig. 2 shows a side elevational view of the same structure.

Fig. 3 shows an elevational view of an electron tube.

whichemploys my rigidizing means in combination. withits cooling structure.

ig. 4. shows in partial section: the electron tube. and. rigidizing means of Fig. 3.

Fig. 5 shows a bottom elevational view of a modified. form of rigidizing means whereon a modified flange means is employed.

Fig. 6 shows the same structure in elevation from the side.

Figs. 1 and 2 illustrate the simplest, preferred form of our rigidizing means which consists merely of a circular planar member 10 having a central circular opening therethrough with a tubular flange 11 fixed perpendicularly to the planar member 10. It is usually convenient to make the planar member 10 of relatively heavy gauge metal or other essentially rigid, yet somewhat resilient, material. Member 10 need not always be circular itself nor need the hole at its center always be circular, but some portion of it must always extend radially so that it will bear against coaxial members at one end of the tube.

Figs. 3 and 4 illustrate how the rigidizing means may be used with a coaxial tube structure to prevent flexing and breaking of the tube envelope. The tube shown is a triode of the inverted lighthouse type, but: any coaxial tube having adjacent envelope portions may use this novel rigidizing means. In this common case member Iii rests against anode ring terminal 12 and simultaneously against anode block 13. It held securely against terminal 12 and block 13, member 10 will prevent bending and flexing of envelope parts, particularly the reentrant shell member 14 aflixed between the anode block and the tubular terminal 12. It may also prevent the cracking of the glass ring 15 to which terminal 12 is sealed. It may be noted in passing that member 10 may be made having a radially stepped shape in order to bear against coaxial parts of structures at diiferent axial levels, but such modification is obviously inconvenient. The anode block is normally hollow, in part to accommodate the exhaust tubulation 16. This hollow is commonly enlarged to accept the tubular support 17 of cooling fins 18. As shown here, this tube appendage may be aflixed by threaded engagement with the anode block or it may be affixed thereto by any other conventional means. The tubular support passes through the central opening of the rigidizing means so that the flange portion 11 of this means rests in its final position atop the fins 18. As is shown Our invention prevents such an occurrence by- Y a "it here, an extra heavy fin 18a may be used to increase its rigidity since it is the member supplying axial pressure through flange 11 to the rigidizing means. Of course, when the cooling fins are not relied upon for the needed axial pressure upon the rigidizing means any other tube appendage or fixture may be relied upon for the same purpose.

Figs. 5 and 6 illustrate one change that is possible in the rigidizing means. Tubular flange 11 is here modified to a series of short radial flanges 11 perpendicular to the planar member 10'. Other modifications in the shape of flanges are possible as are modifications in the shape of the central opening and in the overall shape of the planar member 10.

It is, of course, possible to use our rigidizing means, with suitable insulation, where necessary, between any coaxial members of the tube envelope. In some instances it may even be possible that some portion of the tube envelope itself may pass through the central opening of the rigidizing means, thus simplifying the type of appendage necessary to exert the needed axial pressure.

All modifications in shape and use as suggested above or in the claims are intended to be within the scope and spirit of our invention.

We claim:

1. Means in addition to an electron tube envelope for increasing the rigidity and preventing the relative radial movement of members of the anode assembly of said electron tube, which members are coaxial and radially separated from one another, comprising a circular planar essentially rigid member which has a central circular opening through it through which connecting means between the anode assembly and cooling means may pass, one side of which planar member bears against coaxial, radially spaced portions of the anode assembly and the anode terminal and the other side of which member has a plurality of radially extending flange members arranged in a circle surrounding the central circular opening.

2. An electrode assembly comprising a hollow tubular electrode and supporting means therefor, connecting means securing together said electrode and supporting means and including a housing member and a shell member secured together at one end, the shell member at its other end being secured to the electrode, and the housing member at its other end being secured to the supporting means, an annular planar member bearing against the end of the connecting means and the electrode, and cylindrical means connecting the electrode with and bearing radially against the planar member.

3. An electrode assembly comprising a hollow tubular electrode and supporting means therefor, connecting means securing together said electrode and supporting means and including a housing member and a shell member secured together at one end, the shell member at its other end being secured to the electrode,-and the housing member at its other end being secured to the supporting means, an annular planar member bearing against the end of the connecting means and the electrode, tubular flange means on the inner periphery of the annular planar member, and cylindrical means connected to the eelctrode andextending through and bearing radially against said tubular flange means.

References Cited in the file of this patent UNITED STATES PATENTS 2,367,331 Bondley Jan. 15, l945 2,446,017 McArthur et al July 27, 1948 2,455,868 Koch Dec. 7, 1948 2,462,921 Taylor Mar. 1, 1949 2,481,026 Law et al. Sept. 6, 1949