US2065667A - Mount for electron discharge devices - Google Patents

Description

Dec. 29, 1936. K. DREYER 2,065,667,

MOUNT FOR ELECTRON DISCHARGE DEVICES Filed Dec. 1, 1933 'mbeOawa he:

INVENTOR KARL DREYER ATTORNEY Patented Dec. 29, 1936 UNITED S'TTES PATENT OFFICE MOUNT FOR ELECTRON DISCHARGE DEVICES ware Application December 1, 1933, Serial No. 700.453

3 Claims.

My invention relates to improvements in electron discharge devices and more particularly to an improved mount construction by which the mount is resiliently held in position in the bulb.

In radio tubes with the dome type bulb the dome or constricted portion at the top of the tube is utilized to steady the electrode assembly and to keep the assembly from vibrating transversely of the bulb. A resilient support or brace between the mount and the bulb wall is desirable in order to prevent noises, such as clicking, caused by the electrode assembly striking the wall of the bulb when the tube is jarred or vigorously shaken. Metal springs for bracing the mount to the bulb walls are not feasible as there is a tendency for the glass bulb to crack, especially during exhaust at those points where the metal touches it.

One object of my invention is to resiliently support or brace the free end of an electrode mount from the walls of the bulb by resilient means which engage the walls of the bulb without cracking or otherwise injuring the bulb.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing, in which Figure 1 is a view in perspective and partly broken away of an electron discharge device embodying my invention;

Figure 2 is an enlarged horizontal cross section along line 2-2 of Figure 1;

Figure 3 is a View, with the bulb wall section, along the line 33 of Figure 2;

Figure 4 is a side and edge view of a punched blank from which the mica supporting clip in accordance with my invention is made;

Figure 5 is a view in elevation of a mica spring and its supporting clip attached to it, and

Figure 6 is a side and edge view of a blank for a modification of a mica supporting clip made in accordance with my invention.

The electron discharge device shown in Figure 1 has a bulb II] with a dome at the top and the usual stem and press II and the usual base I2 at the bottom. The electrode assembly I 3 is mounted on the stem II and its upper end projects into the tubular portion or dome of the bulb I0. The electrodes are accurately spaced by a pair of insulating bars, one at each end of the electrode assembly, such as a bottom mica I4, fastened to the plate electrode by straps I5, and a top mica I6, located at the top of the electrode assembly. The upper end of the electrode assembly is firmlyyet resiliently steadied from the bulb walls by spacers I I of resilient insulation, such as sheet mica, mounted at the ends of the top mica I6 to rest against the walls of the bulb I0. These strips or spacers are mounted parallel to the vertical axis of the dome of the bulb and lie fiat to the wall, with their ends in contact with the wall and their intermediate portions spaced away from the wall.

The fiat mica spacers H are mounted on the upper end of the electrode assembly by metal clips or supports I8, which, as best shown in Figure 4, are conveniently made from blanks punched from sheet metal and folded along the dotted lines into the shape shown in Figures 1, 2, and 3. These clips have fingers I9 and 20 which are bent over to grasp the mica spacer I 1 near the middle and hold it in the clip, as shown in Figure 5. The mica spacer I! has in its lower edge a recess for the finger 20, which thus prevents the spacer slipping endwise and out of the clip. The clip has near its ends grooves 2| which form, when the clip is closed, a channel for receiving the upper ends of the plate side rods of the electrode assembly. The clip blanks also have slots 22 to receive the ends of the upper mica I6 when the clips are fastened, preferably by welding, to the upper end of the electrode assembly, as shown in Figures 1, 2, and 3. These slots 22 enable the clips to hold the upper mica I6 firmly in place on the electrode assembly, so that straps, such as I5, are not needed to hold the upper mica to the assembly. The clip or support I8 is advantageously made of sheet metal, but could be made integral with some metal part, such as the plate of the electrode assembly.

When, during assembly of the tube, the bulb is placed over the electrode assembly the ends of the mica spring spacers I1 rest against the curved inner wall of the tubular portion or dome of the bulb I I). These spacers, which are secured intermediate their ends to the electrode assembly, are of such a length that they are, as shown in Figure 2, bent slightly when in the dome, hence they act to resiliently support or brace the electrode assembly and hold it steady in the bulb. The clips I6 position the mica spacers accurately with respect to the assembly and the dome of the bulb and prevent displacement of the spacers during assembly of the tube. Because of the resiliency of the mica spacers the usual and unavoidable variations in bulb diameter are compensated for and looseness of the electrode assembly in the tube is avoided.

In one form of my invention as embodied in a tube made with a bulb having straight sides and a tubular extension or dome and usually known as STI4, and having a dome about 1.30" in diameter, I have obtained good results by using mica spacers I! about .95" long placed about .93 apart, so that their ends rest against the walls of the dome. Mica spacers from 8 to 12 mils thick will be sufiiciently resilient to give the desired results, and be suificiently flexible to compensate for the unavoidable slight variations in diameter of the bulb.

Figure 6 shows the clip I 8 modified to have spurs or pointed projections 23 which extend through the mica spacer and are bent over to fasten the spacer in place in the clip. Obviously, the mica spacer may be fastened to the metal clip in various other ways.

While I have indicated the preferred embodiment of my invention of which I am now aware and have also indicated specific applications for which my invention may be employed, it will be apparent that my invention is not limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed, Without departing from the scope of my invention as set forth in the appended claims.

What I claim is:

1. An electron discharge device provided with an envelope having a tubular portion, a mount comprising an electrode assembly within said envelope and extending within said tubular portion, supporting members secured to said electrode assembly and provided with a grooved portion, and sheet mica springs engaged intermediate their ends by the grooved portion of said members and set perpendicularly to the transverse axis of the tubular portion of said envelope with their ends in engagement with the walls of said tubular portion to resiliently and accurately position the mount within the tubular portion of said envelope.

2. An electron discharge device provided with an envelope having a tubular portion, a mount comprising an electrode assembly within said envelope extending Within said tubular portion, supporting members comprising a punched blank folded to provide a flat surface having projections thereon and an extension for securing said supporting members to the electrode assembly with the flat surface parallel to the longitudinal axis of said tubular portion, sheet mica springs in engagement with said flat surfaces, the projections on said flat surfaces being formed to maintain said mica springs in engagement with said supporting members and with their ends in engagement with the Walls of said tubular portion to resiliently support the mount within the tubular portion of said envelope. I

3. An electron discharge device provided wit an envelope having a tubular portion, a mount comprising an electrode assembly within said envelope extending within said tubular portion, a flat insulating spacer for said electrode assembly extending transversely of said tubular portion, supporting members having extensions for securing said members to said electrode assembly, said extensions being provided with a slot for receiving said insulating spacer to lock said spacer on said electrode assembly, mica springs set parallel to the longitudinal axis of the tubular portion of said envelope, and means on said supporting members to engage said mica springs intermediate their ends with the ends of said mica springs in-engagement with the tubular portion of said envelope to resiliently support said mount within said envelope.

KARL DREYER.

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