US1999351A

US1999351A - Electron discharge device

Info

Publication number: US1999351A
Application number: US570531A
Authority: US
Inventors: Carl I Baker
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1931-10-23
Filing date: 1931-10-23
Publication date: 1935-04-30
Anticipated expiration: 1952-04-30

Description

April 3@, m3;

c. I. BAKER ELECTRON DISCHARGE DEVICE Filed Oct. 23, 1931 LQEEEM 29 lNl/EA/TOR CJBA/(ER ATTORNEY Patented Apr. 36, 1935 UNlTED STATES PATENT OFFICE Telephone Laboratories, York, N. Y., a corporation Incorporated, New of New York Application October 23, 1931, Serial No. 570,531 10 claims, (01. 250-275) This invention relates to electron discharge devices and more particularly to an electrode assembly in such devices.

The static and dynamic characteristics of electron discharge devices are largely dependent upon the space relation of the several electrodes. Any change in this relation, particularly such changes as are occasioned by mechanical and acoustic shocks to which the device may be subjected during operation, produce objectionable microphonic disturbances which result in unfaithful and distorted reproduction.

An object of this invention is to prevent external disturbances from affecting an electron discharge device.

Another object of this invention is to unify the electrode assembly in electron discharge devices and to facilitate the fabrication thereof.

In one embodiment of this invention an elec-' tron discharge device comprises an enclosing vessel having a stem and a unitary electrode assembly resiliently supported from the stem. The electrode assembly includes a rigid anode which supports twin insulating members at each end thereof, and a cathode and grid supported by the insulating members within the anode. A pair of uprights extend from the stem and carry spring members which are secured to the electrode assembly near one end thereof. Other spring members are mounted on supports extending from the stem and are secured to the other end of the electrode assembly. The spring members may be of electrically conductive material and may be utilized as connecting links between the electrode leading-in wires and the electrodes. Furthermore, the spring members may also be so designed by selection of the material and elasticity thereof that the electrode assembly will have a predetermined natural frequency of vibration, such as the resonant frequency of a circuit in which the device is to be utilized.

The invention will be understood more clearly and fully from the followl g detailed. description with reference to the accompanying drawing:

Fig. 1 is a perspective View of an electron discharge device made in accordance with this invention with portions of the enclosing vessel and the anode broken away to show the inner electrode structure more clearly;

Fig. 2 is another perspective view from a different angle of the discharge device shown in Fig. l with a portion of the enclosing vessel broken away, showing the resilient mounting of the electrode assembly within the enclosing vessel;

Fig. 3 is an end plan view of the electrode unit assembly Showing the relation of the electrodes and the supports at one end of the unit;

Fig. 4 is another end plan View of the electrode unit assembly at the opposite end of the unit; and

Figs. 5 and 6 are enlarged detail views showing 5 the attachment of the spring members to the supports and to the electrode assembly.

Referring now to the drawing, an electron discharge device, in one embodiment of this invention, comprises an enclosing vessel l0 having a 10 reentrant stem l l which terminates in a substantially rectangular press l2. The vessel I0 is secured, as by cementing, to an insulating base l3 carrying terminal prongs 14 (only one of which is shown) for associating the device with an elec- 15 trical' circuit. A plurality of rigid rods l5 and I6 having parallel portions extending lengthwise of the vessel Ill are embedded in the press l2 and together with a plurality of bent wires H and it support a unitary electrode assembly. 2

The electrode assembly comprises a flattened cylindrical anode l9, and M-shaped filamentary cathode 2i], and a helical control electrode or grid 2i encircling the cathode and uniformly spaced between the cathode Z0 and the anode [9. The 25 anode I 9 may be of carbonized nickel or any suitable conductive material and comprises two similar plate portions having integral flanges 22 joined together, and provided with parallel spaced ridges or embossments 23 for increasing the rig- 3 idity of the anode to prevent undesirable and excessive distortion or buckling thereof due to temperature' variations during the operation of the device.

A pair of metallic rods 24, which are secured 5 to the flanges 22 of the anode, extend beyond the ends of the flanges 22 and support two unitary twin insulator assemblies. The assembly adjacent the top of the enclosing vessel Ill, as shown in Fig. 3, comprises two substantially parallel insulating

members

25 and 26, such as glass beads or rods. These beads are rigidly connected together and spaced apart by short wires 2! which have their ends embedded in the insulating

members

25 and 26, the wires 21 being attached, for instance, by spot welding at substantially their midpoint to the metallic rods 24 adjacent one end of the anode E9. The assembly adjacent the press l2, as shown in Fig. 4, likewise comprises a pair of substantially parallel insulating

members

28, 29 rigidly connected together and spaced by short wires 30 which are secured to the metallic rods 24 adjacent the other end of the anode IS.

A plurality of rigid wires 31 extend between and are embedded in the insulating

members

25, 26. 5

Similar wires 32 extend between and are embedded in the insulating

members

28, 29. A pair of parallel rigid metallic rods 33 extend between and are secured to the

wires

35, 32 and support the helical control electrode or grid 21 concentric with and uniformly spaced from the anode iii. A pair of wires 34 are embedded in the central section of the insulating member 25 and bent around the bead 25 to support flexible wires 35 which carry hook members 36 engaging the bights of the vi-shaped cathode 20. The midpoint of the cathode 25 is engaged by a hook member 3i which is carried by a rigid wire 38 extending inwardly from the insulating member 25. The ends of the cathode 2d are secured to wire connectors Ail and 56 which are attached to wires 39, embedded in and extending from the insulating members 28. The flexible wires 35 allow longitudinal expansion and contraction of the filamentary cathode 28 with temperature variations during the operation of the device and maintain the filament taut and in the proper space relation with the grid and anode. This construction provides a compact and rigid electrode assembly which may be readily fabricated and mounted as a unit within an enclosing vessel.

In order to prevent changes in the space relation of the electrodes by acoustic or mechanical shocks and to thereby maintain the characteristics of the electron discharge device uniform, the unitary electrode assembly described above may be resiliently supported within the enclosing vessel ill as described in detail hereinafter.

A U-shaped or bowed resilient support or spring member 40, which may be of fine tungsten wire, is secured at its ends to the rigid rods 24 and at its center to the rigid rod l5. In order to increase the surface area of the spring member and insure a rigid connection between the spring it and the rods 24 and I5, a sleeve ll, for example, of nickel surrounds the spring ll! at the points of contact with the rods 24 or iii as shown n Fig. 5. This sleeve may be easily welded to the support rods without danger of weakening the fine spring member by corrosion or melting. A leading-in wire 42 is embedded in the stem ll and electrically connects the rod l to one of the terminal prongs M so that the rod l5 and r the support All serve as current supply connec tions for the anode l9.

Another bowed or U-shaped support or spring member 33, of fine tungsten wire, is secured to rod l6 and to the grid supporting rods 33'by spot welding, through metallic sleeves M similar to the sleeve ll. A leading-in wire 45 embedded in the stem ll electrically connects the rod it to one of the terminal prongs Hi so that an electri cal connection is established between the grid 2i and one of the termmals l through the support A pair of resilient circular or elliptical supports or spring members 35, ll of tungsten wire, are secured to the bent wires 61, i8 respectively, for example, by spot welding through metallic sleeves 38 as shown in Fig. 6, and encircle the rigid rods 55, 5E. The supports 4%, ti are similarly secured to this short wire connectors Q9, 5!; respectively, with the aid of nickel sleeves 53. Current is supplied to the cathode 29 through the circular or elliptical supports i5, ll and through leading-in wires 55, 52 embedded in the stem H and electrically connected to the bent wires ll, l8 and to certain of the terminal prongs l4.

. The resilient supports, 48, 43, 46 and all protect the electrode assembly against acoustic and mechanical shocks so that the electrodes are maintained in the proper space relation, microphonic disturbances are eliminated, and undistorted reproduction is realized with the device.

The resilient supports may be utilized so that the electrode assembly Will have a predetermined natural frequency of vibration substantially the same as the resonant frequency of a circuit in which the device is to be employed. This is accomplished by regulating the stiffness, diameter and length of the spring members to achieve the desired result.

Although a specific embodiment of the invention is disclosed and described herein, it is to be understood that many modifications may be made in the structural assembly of the device without departing from the spirit and scope of this invention as defined in the appended claims.

What is claimed is:

1. An electron discharge device comprising an enclosing vessel having a stem, an electrode as-' sembly including an anode, a cathode resiliently and insulatingly supported from said anode, and means supporting said assembly from said stem, said means including a resilient member secured to said anode adjacent one end of said assembly and another resilient member secured to said cathode adjacent the other end of said assembly.

2. An electron discharge device comprising an enclosing vessel having a stem, a plurality of rigid rods projecting from said stem and extending lengthwise of said enclosing vessel, a plurality of metallic connecting members in said stem, a unitary electrode assembly including an anode; a cathode and a grid mechanically coupled to and insulated from said anode, a resilient member extending from one of said rigid rods and secured to said anode at one end of'said assembly, a resilient member extending from another of said rods and secured to the grid at the same end of said assembly, and a plurality ofresilient members extending from said connecting members and secured to said cathode adjacent the other end of said assembly.

3. An electron discharge device in accordance with claim 2 in which the resilient members serve as current conductors for said anode, grid and cathode.

4. An electron discharge device comprising a. unitary electrode assembly including an anode, a plurality of spaced insulating members supported from said anode at opposite ends thereof, a plurality of electrodes cooperatively associated with said anode, mounted between said members and supported thereby, and means mounting said assembly within said vessel, said means including a resilient member secured to said assembly adjacent one longitudinal extremity thereof, and another resilient member secured to said assembly adjacent the opposite longitudinal extremity thereof.

5. An electron discharge device comprising an enclosing vessel having a stem, a unitary electrode assembly including an anode, twin insulating members mounted on said anode at opposite ends thereof, a grid supported by said members within said anode, a filamentary cathode within said anode and grid resiliently supported between certain of said members, and means for resili ently supporting said assembly from said stem, said means including electrically independent flexible members associated with said anode, grid and cathode and serving as current conductors therefor.

6. An electron discharge device comprising an enclosing vessel having a stem, a plurality of rigid members extending from said stem, a unitary electrode assembly including an anode, a pair of insulating members mounted on said anode at each end thereof, and a cathode and a grid supported between said insulating members, resilient members adjacent one end of said assembly extending from said anode and said grid to individual rigid members, and resilient members adjacent the other end of said assembly extending between said cathode and other individual rigid members.

'7. An electron discharge device in accordance with claim 6 in which the resilient members are bowed springs and serve as current conductors for said cathode, grid and anode.

8. An electron discharge device comprising an enclosing vessel having a stem, leading-in conductors embedded in said stem, an anode beyond said stem, a cathode and grid mechanically coupled to and insulated from said anode, resilient means attached to said anode and grid and connected to individual leading-in conductors, and looped resilient means attached to said cathode and other leading-in conductors and surrounding said anode and grid leading-in conductors.

9. An electron discharge device comprising an enclosing vessel having a stem, a unitary electrode assembly including an anode, sets of insulating beads positioned at opposite ends of said anode, means connecting said beads to said anode, a helical grid within said anode, supporting means extending between individual sets of beads attached to said grid, a filamentary cathode within said grid and anode, supporting means extending between one set of beads for connection to said cathode at one end of said anode, bent Wires extending from an individual bead of the other set of beads, flexible connections from said Wires to said cathode at the opposite end of said anode, rigid rods projecting from said stem outside the boundary of said unitary assembly, arouate resilient springs connected to said rods and anode and grid respectively, and closed looped resilient springs connected to said cathode and stem and surrounding said rigid rods.

10. An electron discharge device in accordance with claim 9, in which metallic sleeves surround the resflient springs at the point of contact with the rigid rods.

CARL I. BAKER.