US2005419A - Vacuum device - Google Patents

Description

June 18, 1935. R. F. GOWEN El AL VACUUM DEVICE 2 Sheets-Sheet 1 Filed April 5, 1918 K J a r j 0 0 m 4 A 1 W .L m T a, mu m w 6 MW M W ff Jv a M wk;

June 18, 1935. GQWEN 2,005,419

VACUUM .DfivIcE 2 Sheets-Sheet 2 Filed April 3, 1918 J v m a rwa /07" M Patentedlune 18, 1935 g i i .UNITED .STATESjPATENTOFFlCE 2,005,419 VACUUM DEVICE Robert F. Gowen, Ossining, N. Y., and James L. Bradford, Elizabeth, N. J., assignors, by mesne assignments, to Radio Corporation of America, a corporation of Delaware Application April-3, 1918, Serial No. 226,537 7 Claims. (01. 250-215) g This invention relates to vacuum devices, and Fig. 12 is a bottom pl n Vi w Of h Construcmore particularly to devices of this nature used tion shown in Fig. 10. for the purpose of detectors, amplifiers, and os- The same part is designated by the same refercillation generators, such as are in use in radio ence character wherever it occurs throughout the communication work, and commonly known as several views.

audions. Our present invention is directed to a compact, The object of the invention is to provide a denovel and efficient arrangement of elements in vice of the character described which is simple vacuous vessels or tubes known as audions, and

in structure, efiicient in operation, and economiwhile the same is particularly adapted for use as v cal of manufacture. an audion, and although for the purpose of illus- 10 A further object of the invention is to provide tration, we will hereinafter refer to the same a device of the character described which is as an audion, we wish it to be understood that the rigid, stable, small and compact, and which will invention is not to be limited or restricted in this afford long life with hard usage. respect.

A further object of the invention is to pro- In wire or wireless communication work where 5 vide a new and improved grid electrode for dea detector, amplifier or oscillation generator, vices of this character. known as the oscillion, is required, or is used, it A further object of the invention is to prois greatly to be desired to have a. device which vide a new and improved mounting for the grid, is simple in structure, efiicient in operation, and

filament and plate electrodes used in devices of economical of manufacture, in addition towhich 20 this char cter. compactness, rigidity and strength is a requisite.

Furthe mbjects of the invention will appear Due to the characteristics of the device, the same more fully hereinafter. being an evacuated vessel, usually and preferably The invention consists substantially in the conof glass, the advantages of a compact, rigid, strong struction, combination, location, and relative arunit are apparent. 25 rangement of parts, all as will be more fully In accordance with our invention we provide hereinafter set forth, as shown by the accomwhat we will term the base indicated generally panying drawings, and finally pointed out in at I blown from glass in the usual manner, which the appended claims. is in the form of a hollowed stem, having anchored Referring to the drawings: therein the supports 2 for the plate electrode, sup- 30 Fig. 1 is a view in elevation of an electrode ports 3 for the grid electrode, and supports 4 for base employed in accordance with our inventhe filament electrode. Connected to the 'filation. ment supports 4 are the filament leads 5 and 6 Fig. 2 is a similar view showing the filament respectively, and connected to one or more of the electrode applied thereon and placed under tengrid supports 3 is the grid lead 7, and connected 35 sion. to one or more of the plate supports 2 is the Fig. 3 is a similar view of the grid electrode plate'lead 8. The respective leads to the grid,

ready for application. plate and filament electrodes extend through the Fig. 4 is a top plan view of the same. base I down through the hollowed or stem portion Fig. 5 is a view of a section of material from thereof as clearly shown. Also anchored in the 40 which the grid electrode is made prior to bebase I is a forked support 9, that is, a support ing placed in condition for use. extending vertically upward and provided with a Fig. 6 is an enlarged detail view in horizontal forked end. The filament electrode I0 is suitably section of one side of a grid winding. secured, as for example, welded to ,the supports Fig. 7 is a view in side elevation of same. which are bent outwardly away from each other 45 Fig. 8 is a view similar to Figs. 1 and-2 showing in the form of a spring and the filament extends the grid electrode mounted and in position. from one support to the other over the forked Fig. 9 is a view in partial vertical section of end of the vertical support 9. The vertical supan assembled. device viewing the plate electrode port 9, it will be noted as shown in Fig. 1, i

in side elevation. vided with an irregularity or bend in the body 50 Fig. 10 is a similar view, viewing the plate thereof. The purpose of this bend is to insure a electrode in central longitudinal section. proper tautness of the filament it. The; filament Fig. 11 is a sectional view taken on the line II, In is usually and preferably of tungsten, and as H, Fig. 9, and looking in the direction of the same is provided with current to heat the samein 5 arrows. its use, becoming heated and cooled repeatedly causes the same to expand. It is necessary in maintaining the efficiency of the device to maintain the filament I 0 taut. Thus it will be seen that after the filament has been welded to its supports 4 when the vertical forked support 9 isstraightened into the position shown in Fig. 2 the filament Ill is stretched into a taut position imposing a strain on the spring supports 4, which spring supports 4 thereafter maintain the filament ID in a taut condition under all conditions of operation, either when the electrode is cold or expanded when heated. As above explained, the grid electrode comprising the parts I2, I3 and I4 is mounted on the supports 3 in any suitable manner, for example, by being welded thereto.

We will now describe the method of construction of the grid, the mounting thereof, and its ultimate position shown relative to the filament. The grid electrode comprises two supporting members I2 and I 3 of small diameter metal, about which is wound spirally at a constant pitch a wire I4. The wire I4 is welded to each of the supports I2 and I3 on the exterior portion thereof as indicated at I5, Fig. 6. In Fig. 5 we show a strip from which the grid electrode is made in which the wire I4 has been wound around the supports I2 and I3 and welded thereto as above explained. We find that it is advantageous to maintain the coils of the wire I4 in a taut condition and equally spaced relative to each other in all positions, therefore we have found that by depressing the wires on one face of the strip in one direction as indicated at I5 and the wires on the other face of the strip in the opposite direction the space,between the respective coils remains constant and all slack in the wire between weldedpoints is thus eliminated. It is necessary to maintain the opposite faces I6 and ll of the grid electrode in a plane parallel to the plane in which is located the filament electrode. We have also found that greater efliciency 'of the device is secured by spacing the coils one-sixteenth of an inch apart, within which space is located the filament electrode. We also find that a space between windings of the grid electrode of onesixteenth of an inch enhances the efliciency of the audion. We also find that a grid wire of diameter of .008 inch is preferable to use, the

grid supports I2 and I3 being located .030 inch apart. Although a great number of tests and experiments extending over a period of considerable time has resulted in our adoption of the foregoing specifications as the preferable form, we do not desire to be limited or restricted to these details. We have found it advisable and preferable to use enough grid wire to completely cover the filament electrode. In the foregoing example we have found that a grid electrode comprising nine coils of wire to be the most efiective. After the audion base has been constructed as shown in Fig. 2 the grid electrode shown in Fig. 3 is then mounted on its supports 3 and suitably secured thereto, for example, by being welded thereto, with the filament electrode positioned between the opposing faces I6 and I! of the grid electrode and with the faces I8, I1, and the filament I0, all located in parallel planes with the filament I0 an equal distance between the opposed faces of the grid wires. The plate electrode I8 comprising preferably a single sheet of nickel of suflicient width to completely enclose the grid electrode and suillcient height to pass over the same rectangularly as clearly shown in Figs. 9 and 10 is suitably secured, for example,

by being welded, to the plate supports 2. The

plate electrode I8 comprises the two side members and a-top with a central opening stamped out of the top, which side members are bent down into planes parallel with the plane of the grid electrode and the filament electrode and spaced an equal distance from its cooperating side of the grid electrode. The device thus far constructed is then enclosed in preferably 'a glass vessel I9, which vessel is thereupon sealed to the base I and evacuated to the proper degree of evacuation required in devices of this nature, and is then sealed off leaving a completed compact audion structure of exceeding strength and rigidity and remarkable efiiciency, with all of the leads of the electrodes extending out of the saine at one point, namely, through the hollow stem portion of the base I, as clearly shown in Fig. 9.

We will now describe the mounting of the audion which permits of added strength and affords to a great extent a protection against the glass vessel IQ of the device becoming broken. The audion vessel I 9 is inserted in a receptacle 20 of any suitable construction, preferably of metal, as shown in Fig. 9, and is anchored therein in any suitable manner, preferably by means of an insulating adhesive compound indicated at 2I. It will be noted that the body of the vessel I9 is substantially enclosed in the receptacle 20 thereby strengthening the same, and due to the width of the receptacle 20 in case the device falls into a horizontal position the glass bulb portion thereof is not subjected-to shock on impact. The respective leads of the electrodes extend down into the receptacle 2!! from the hollow stem portion of the base I and may be insulated from each other in any desired manner, for example, by means of sleeves 22. A cap or cover 23 is inserted in the open end of the receptacle 20 which cap or cover may be of any suitable construction or material. We find it preferable, however, to make the cap or cover 23 of a non-conductive waterproof material, and to coat the edges thereof with a suitable cement or adhesive to effectively seal the interior of the receptacle 2!] when the cap or cover is placed on the same. The cap or cover is provided with four terminals 24 in which the wire leads of the electrodes are located and anchored therein in any suitable manner, for example, by being soldered therein as indicated at 25. In the use of the audions it is preferable to ground one terminal of the filament electrode and preferably the positive terminal. We provide a simple means for accomplishing this wherein the wire 26 is suitably secured to the receptacle 20 inany desired manner, for example, by being soldered therein. This wire 26 is then secured to the wire lead as indicated in Fig. 9. Thus it will be seen that we have provided an audion construction wherein all of the electrodes are provided with leads at one point, namely, the base of the audion terminating in four rigid posts 24, one post being connected to the grid electrode, one to the plate electrode, and two to the filament electrode. This permits the use of a standard socket receptacle for the audion bulb whereby all that is necessary to place the audion in circuit is to place the audion unit into its receptacle thus eliminating making connections by hand and establishing wire leads from various points of the bulb. It may be desired to insure a proper insertion of the audion bulb in its socket and to provide means for retaining the audion bulb in its socket. For this purpose we show at a projection on the receptacle 20, which projection may cooperate with a groove in the receptacle orsocket to form in effect a bayonet lock and at the same time insure proper disposition of the various electrodes of the audion unit.

Many modifications will occur to those skilled in the art without departing from the broad spirit and scope of our invention, as defined in the claims, therefore, what we claim as new and useful, and of our own invention, and desire to secure by Letters Patent, is:

1. A vacuum device comprising a filament and grid electrode, a plate electrode comprising a single piece of metal with a central opening cut therethrough and bent downwardly on opposite sides of said central opening.

2. A vacuum tube comprising a press, a. cathode, a helical grid surrounding said cathode, an anode surrounding said grid, and metallic means connecting said electrodes and said press and forming the sole support for said electrodes.

3. An audion mount comprising a base with a press portion, a pair of metallic spring supporting arms sealed into said press, a filament attached at opposite ends to said arms, another supporting arm sealed into said press intermediate the first mentioned support arms and adapted to engage the filament intermediate its ends to maintain ittaut.

4. An audion mount according to claim 3 in which said other supporting arm has a looped portion intermediate its ends.

5. An electron discharge tube comprising a stem having a press, a plurality of pairs of metallic supports embedded in said press, and cooperating electrodes mounted on said stem and comprising a filamentary cathode secured to and carried by one pair of said supports, a grid comprising a pair of independent metal rods mounted parallel to each other on opposite sides of said cathode with their ends joined to another pair of supports and a continuous wire wound around said rods into a flattened helix coaxial with and surrounding said cathode and having each turn secured to said rods and an anode supports constituting both the electrical connections and the sole supporting means for said electrodes.

6. An electron discharge tube comprising a stem having a press, a cathode electrode, a grid electrode coaxial with said stem and surrounding said cathode and comprising a pair of metal rods mounted at one end on said press and projecting side by side and independent of each other from said press on opposite sides of said cathode and a wire wound around said rods forming a continuous helix surrounding said cathode with each turn secured to said rods, an oblong anode electrode of sheet metal coaxial with and surrounding said grid and open at both ends and having two sheet metal side portions disposed on oppositesidesof said grid and parallel to the plane of said rods, each of said portions being wider than said grid and of a height as great as the length of said grid, and metal wires sealed into said press and connecting said electrodes and said press and constituting the sole supports for said electrodes.

7. An electron discharge device comprising a press, a cathode on said press, an oblong anode coaxial with and surrounding said cathode, and a grid electrode on said press comprising two parallel side rods mounted at one end on said press and projecting from said press with their other ends free, said side rods being held spaced from each other solely by said press, and a grid wire wound over said rods into a. continuous helix of substantially the length of said Beds with each turn of said helix joined to said rods and surrounding said cathode, thereby interposing between said cathode and said anode intermediate said two side rods only those portions of said grid electrode which consist solely of turns of grid wire.

ROBERT F. GOWEN. JAMES L. BRADFORD.

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