US2981897A

US2981897A - Electric discharge device and socket

Info

Publication number: US2981897A
Application number: US464079A
Authority: US
Inventors: James E Beggs
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1954-10-22
Filing date: 1954-10-22
Publication date: 1961-04-25
Anticipated expiration: 1978-04-25

Description

April 25, 1961 J. E. BEGGS 2,981,897 ELECTRIC DISCHARGE DEVICE AND SOCKET Filed Oct. 22, 1954 2 Sheets-Sheet 1 4/ [nu/enter":

.J c/Iames 56:295,

i725 Attorney.

il 25, 1961 J. E. BEGGS ELECTRIC DISCHARGE DEVICE AND SOCKET Apr 2 Sheets-Sheet 2 9.

fnvenor James E. fieggs, by 24% 4 M fi ls Attorney.

United States Patent Q 2,981,897 ELECTRIC DISCHARGE DEVICE AND SOCKET James E. B eggs, Schenectady, N.Y., assignor to General Electric Company, a corporation of New York Filed Oct. 22, 1954, Ser. No. 464,079

12 Claims. (Cl. 331-99) 'lrhis invention relates to an improved electric discharge device and socket assembly. While this invention is sub- Ject to many variations and modifications it is suited for application for use in connection with miniature electric discharge devices and will be described in that connection.

Electric discharge devices and sockets for these devices have been devised and are in use which utilize a series of metallic terminals of varying diameter so that the device can be inserted into the socket in an axial direction. The terminal members of the electric discharge device generally have a greater diameter than the intervening insulating spacers and are therefore subject to damage in handling and to the possibility of short-circuiting when inserted in the socket. In accordance with an aspect of this invention, electric discharge devices are provided with insulating spacers which extend beyond the discharge device terminal members thereby resulting in an electric discharge device which is inherently free of the tendency of the terminals to be short-circuited or damaged during handling.

Operation of electric discharge devices of miniature and sub-miniature sizes is often limited by the ability of the electric discharge device to dissipate heat. Therefore, an electric discharge device which can be operated at relatively high temperatures is ideally suited for handling relatively heavy discharge currents per unit electrode area. A phenomenon resulting from high temperature operation is the emission of gases from the electric discharge device electrodes and envelope so that the electric discharge device becomes gassy and unstable. In accordance with an aspect of this invention, discharge device envelopes include metals which readily absorb gases such as metals from the titanium group which consists of titanium, zirconium, hafnium and thorium. Since titanium and zirconium are readily available and easily fabricated this specification, by way of example, makes particular reference to these metals or alloys thereof. These metals are extremely active so that throughout the range of electric discharge device operating temperatures they absorb stray gases emitted by other electron discharge device elements and, when properly processed prior to tube assembly, these metals emit essentially no gases.

It is therefore an important object of this invention to provide an improved electric discharge device and socket assembly.

Another object of this invention is to provide an improved electric discharge device and socket assembly utilizing an electric discharge device capable of operating at high temperatures and having extending insulating spacers.

It is also an object of this invention to provide an improved socket for an electric discharge device.

A further object of this invention is to provide an improved socket for an electric discharge device incorporating a tuned circuit.

It is still another object of this invention to provide an improved electric discharge device.

An additional object of this invention is to provide an improved electric discharge device capable of continuous operation at sustained high temperatures.

According to an aspect of this invention a socket is Patented Apr. 25, 1961 provided which is adapted to receive an electric discharge device and which includes a plurality of spaced connectors each provided with a recess to receive and make electrical connection to the conductive terminal members of the discharge device. In a specific embodiment of this invention the insulating spacers of the electric discharge device extend beyond the terminal members so as to electrically and mechanically separate the connectors.

Other important aspects and objects of this invention will become more apparent from the succeeding specification and appended claims when taken in connection with the figures of the drawing wherein Figure 1 illustrates an exploded perspective view of an electric discharge device and socket constructed in accordance with this invention; Figures 2, 3 and 4 illustrate components of the socket structure illustrated in Figure 1. Figure 5 illustrates a modification of the structure illustrated in Figure 1; Figures 6, 7 and 8 illustrate examples of electric discharge devices suited for use in accordance with this invention and Figures 9 through 11 inclusive illustrate details of the construction of the electric discharge devices illustrated in Figures 6, 7 and 8.

Figures 1, 2, 3 and 4 of the drawing illustrate an embodiment of a socket assembly in accordance with this invention wherein like members are designated by the same reference numerals. The socket assembly illustrated in Figure 1 consists of

flat metal connectors

20, 21, 22 and 23 which are loosely retained by the base assembly consisting of

members

24, 25 and 26. The base members consist of any suitable insulating material such as, for example, pressed fiber or ceramic and are held together so as to retain the metal connector members and form a complete socket assembly by means of any suitable fastening means such as, for example, rivets 27. The metal connectors are formed of any satisfactory material having high conductivity and sutficient resiliency to provide adequate wiping action on the terminal portions of an electric discharge device and, by way of example, the electrical connectors of this embodiment are formed of sheet spring brass.

Figure 2 illustrates a section along section 2 -2 of Figure l and particularly illustrates the manner of loosely retaining the fiat metal connectors in the socket base. Base member 25 consists essentially of a rectangular ring which separates

base members

24 and 26 so that the connectors can extend through slots provided in

members

24 and 26 and be loosely retained in the base by projecting shoulders 28.

This construction will become more apparent when reference is made to the illustration in Figure 3 which consists of a section taken along line 33 in Figure 2. It is apparent that connector 21 is permitted a considerable degree of freedom of motion while still being effectively retained in the base member consisting of

members

24, 25 and 26. The connectors are provided with U-

shaped openings

29, 30, 31 and 32 and are split along a portion of their length so as to provide slots 33. The U-shaped openings are slightly smaller than the respective terminal portions of the tube tht are to be received, so that the inherent spring action of the connector provides an adequate wiping action and contact with the tube terminal and, further, the respective U-shaped openings have differing sizes so that the electric discharge device can be inserted in one direction only to make the proper connections with an associated circuit.

In the exploded view of the electric discharge device and socket assembly illustrated in Figure l, the electric discharge device is generally illustrated as consisting of

metallic terminal members

34, 35, 36 and 37 which are separated by insulating spacers 38. For example, the illustrated electric discharge device may be considered to consist of a triode vacuum tube wherein terminal 37 is a accuse? heater terminal, terminal 36 is a heater and cathode terminal, terminal 35 is a control electrode terminal and terminal 34 is the anode terminal.

The electric discharge device is easily inserted in the U-shaped openings in the metal connectors and, as will be noted, connector 21 is provided with a greater crosssectional area so as to provide shielding for the control electrode terminal for grounded grid operation of the discharge device. One or more connectors can be provided with an enlarged area as dictated by the specific utilization of the discharge device. Associated circuitry is connected to the lower end of the metal connectors which extend through the base by making connection to terminals 39.

It is noted'that a firm connection is made to the terminals of the electric discharge device without imposing any strain on the electric discharge device envelope. This results from the relatively loose retention of the electric connectors in the base and the spring action of theseconnectors which apply pressure in a radial direction only.

It is often desirable to provide a means of locking the electric discharge device to the socket so as to prevent any possibility of the electric discharge device being shaken loose when the assembly is subject to severe vibration and shock. An example of an embodiment providing a locking effect is illustrated in Figure 4 wherein recess 40 has the shape of a part of a circle rather than the previously described U-shaped construction and the entrance 42 for the electric discharge device is sufficiently restricted so that when the electric discharge device is forced down into recess 40 it will be held by the lip of recess 40 as well as the spring action of the connector member. By incorporating at least one connector of this type in the socket assembly illustrated in Figure 1 a self locking socket is provided.

The discharge device and socket assembly of this invention can be modified to provide a unitary oscillator or tuned circuit structure such as that illustrated in the example shown in Figure 5 of the drawing wherein the connectors extend in a direction away from the electric discharge device so as to provide parallel tuned lines or ribbons 20', 21', 22 and 23'. The lines are terminated by capacitive members such as dielectric strips, 43, 44, and 45. In addition, tuning stubs, such as the conductive members shown at 212 and 223, can be provided between the strips such as strips 21' and 22 to provide a tunable resonant circuit and connections may be made to the various connectors at any satisfactory point, for example, the up-turned tips thereof.

The electric discharge device illustrated in Figure 6 is provided with a conductive shoulder or ground plane 44 connected, for example, to the control electrode and which is incorporated in the electric discharge device structure. This often eliminates the necessity of having a connector with a large cross-sectional area such as the connector 21, unless it is necessary or desirable to provide very complete shielding.

In view of the foregoing, it is readily apparent that the socket and electric discharge device assembly of Figure 1 can be modified to accommodate an electric discharge device having any number of electrodes such as a tetrode or pentode merely by increasing the number of fiat metal connectors retained in the base of the socket assembly. It is further apparent that the insulating separators 38 which constitute a portion of the envelope of the electric discharge device also cooperate with' the socket assembly to electrically and mechanically separate the metal connectors and further to protect the terminals of the electric discharge device. There is no possibility of inserting the electric discharge device incorrectly since the different sizes of the electric discharge device terminals, or of at least two of the electric discharge device terminals, provide a means of assuring that the electric discharge device is inserted in the correct position.

The electric discharge device and socket assembly of this invention provides a means for easily changing electric discharge devices and for mounting these devices in any position with no likelihood that the electric discharge device will become dislodged or shaken loose by shock or vibration. Electric connectors and socket assemblies in connection with electric discharge devices as herein illustrated and described are particularly suited for utilization in large panel assemblies in which the electric circuitry, by way of example, may be printed on the panel assembly which also retains the metal connectors and the connector ends bent over and soldered to the printed circuit.

Figure 7 illustrates by way of example an embodiment of an electric discharge device which is suited for utilization in the socket of this invention. The illustrated electric discharge device is a triode vacuum tube consisting of an anode and anode terminal member 46, insulating spacer 47, control electrode 48, control electrode terminal 49, insulating spacer 50 which receives cathode 51, cathode connector 52, insulating spacer 53 and heater terminal 54. A conductive film 55 is provided on the lower surface of insulating spacer 50 so as to make contact with and seal cathode 51 into insulating spacer 50. The cathode 51 consists of a metallic spinning of metal such as, for example, titanium or nickel, which forms a cup on the inner surface of which is provided an insulating button or wafer 56. A conducting film 57 is applied to the wafer and is connected to the metal cup 51 and to heater lead 58 which is electrically connected to heater terminal 54.

In an example of an embodiment of this electric discharge device, one or more of the metal members forming the tube envelope includes one or more metals from the titanium group metals consisting of titanium, zirconium, hafnium and thorium or alloys thereof, titanium and zirconium or alloys thereof being preferred. For example, the

terminals

46, 49, 52 and 54 are formed of titanium and the insulating

spacers

47, 50 and 53 are formed of a high temperature ceramic material such as. for example, the ceramic materials generally classified as aluminas, zircons, forsterites and beryllias.

The electric discharge device is assembled by stacking the parts in the illustrated manner with interposed shims of metal such as nickel, iron, cobalt, chromium, molybdenum, copper, platinum or alloys thereof which form an alloy having a melting point below the melting point of either the shim metal or the electric discharge device envelope metal. In this example, the discharge device envelope is fabricated from titanium and ceramic parts with interposed nickel shims. The ceramic button 56 and heater lead 58 are glued into the cup cathode 51 with titanium hydride in a nitrocellulose binder and the path of the resistance heater is outlined with nitrocellulose binder. A triple carbonate coating 59 is applied to the top of the cathode 51. A morecomplete description of the fabrication of this cathode and other cathode structures suitable for use in the illustrated discharge device is contained in my copending application Serial No. 464,078 filed herewith and assigned to the same assignee as this application and now Patent No. 2,875,367, granted February 24, 1959. The cathode'is then glued with a nitrocellulose binder into ceramic member 50 and nitrocellulose binder is painted on the underside of ceramic member 50 so as to provide aconductive path between cathode terminal 52 and cathode 51.

The entire assembly is placed in an evacuated chamber and heated to a temperature below the melting point of a titanium-nickel alloy, in the order of 900 C. to degas the component members of the device and form and activate the cathode. The device is then heated to approximately 1000" C. to seal and bond thetitanium members to the ceramic members and complete the tube structure. By heating the tube parts and metal shims therebetween to the melting point of an alloy of the tubeand shim parts,

the alloy readily wets the ceramic parts and results in a strong hermetically tight bond. The alloy also flows over the nitrocellulose coatings which it contacts and which have been carborized by the high temperature heating. This effects. electrical connections between the cathode terminal and the cathode and between the heater lead 58 and the cathode and also bonds the cathodeto ceramic member 50. The conducting film 55 has a low resistance resulting from the application of a relatively heavy coating of nitrocellulose binder and the large amount of metal alloy in the binder and the conducting film 57 has a high resistance resulting from the application of a relatively thin coating of nitrocellulose binder.

The completed tube can be operated in the air at temperatures up to 800 C. without unreasonable oxidation of the titanium parts. Since the internal parts of the electric discharge device have been degassed at uniformly high temperatures, and, in fact, act as a getter for most gases within the tube envelope, essentially no gases are evolved. Therefore, electric discharge devices including these materials display uniformly stable emission.

Applicants copending application entitled Metallic Bond, Serial No. 409,159, filed February 9, 1954, now Patent No. 2,857,663, granted October 28, 1958, describes in greater detail other combinations of materials which may be utilized to form satisfactory hermetic bonds between metals and between metals and ceramics. It is considered to be within the scope of this invention to .utilize electric discharge devices incorporating any of the combination of metals or alloys thereof disclosed in this application. That is, the tube, for example, can be constructed of copper or nickel parts and be assembled with titanium or titanium and zirconium shims inserted between the metal tube parts and the ceramic tube parts. however, results are better in general when one or more titanium parts are used in the assembly and the titaniumnickel shim combination is preferable from the point of view of metallic vapors since both nickel and titanium have low vapor pressures at 1000 C. while a titaniumnickel eutectic alloy melts at a temperature below 1000 C. When copper shims are utilized degassing and cathode activation is carried out at a temperature of the order of 850C. and sealing at a temperature of the order of 900 C. It will be appreciated that electric discharge devices formed of any number of other materials can be utilized in the practice of this invention and that the device and construction thereof which is hereinafter described, is given merely by way of example. 4 The method of making tubes of the type illustrated in Figure 7 is more completely described and is claimed in my copending application Serial No. 464,126, filed concurrently herewith and assigned to the same assignee as this invention now Patent No. 2,868,610, granted January It is further fully anticipated and considered to be within the scope of this invention to utilize electric discharge devices having the general configuration of that illustrated in Figure 7 which are formed and sealed in accordance with the methods and teachings of my copending application Serial No. 464,077, filed herewith and assigned to the same assignee as this invention now Patent No. 2,792,272, granted May 14, 1957.

Figure 8 illustrates a multi-electrode electric discharge device of construction similar to that illustrated and described in connection with the tube illustrated in Figure 7. This tube consists of anode and anode terminal 60, ceramic insulating spacer 61, electrode 62 and electrode terminal 63, ceramic insulating spacer 64, electrode 65 and electrode terminal 66, ceramic insulating spacer 67, electrode 68 and electrode terminal 69, ceramic insulating spacer 70 which receives cathode 71, cathode terminal 72, ceramic spacer 73 and

heater terminals

74 and 75. The heater structure consists of heater leads 76 and 77 which are connected to a conducting film 78 which is placed on the base of a ceramic button or wafer 79.

For example, the conducting film can be formed by coat ing wafer 79 with nitrocellulose and firing to form a carbon path. An emissive coating 80, such as, for example, the customary triple carbonate coating, is placed on top of the cathode cylinder.

The cathode and the construction thereof is more completely illustrated in Figure 11 wherein like parts are, designated by the same reference numeral. The construction of cathodes and the formation of conducting films such as conducting film 78 are more completely described in my copending application, Serial No. 464,080, filed herewith and assigned to the same assignee as this application and my aforementioned application, Serial No. 464,078. The electric discharge device illustrated in Figure 8 is assembled, activated, degassed and sealed in the same manner as described in connection with the electric discharge device illustrated in Figure 7.

The electric discharge device illustrated in Figure 8 has a separately heated cathode and therefore two heater leads 76 and 77 must be brought out to

heater terminals

74 and 75 which are shown in greater detail in Figure 10. In order to avoid the possibility of short-circuiting the heater power supply the anode terminal 60, shown in Figures 8 and 9, is provided with two flattened portions 60a and 60b and the corresponding socket connector consists of two metal strips insulated from each other which provide a recess therein of sutficient width to accommodate the least dimension of anode terminal 60 only, so that short-circuiting of the heater power supply, as a result of incorrect insertion of the electric discharge device in the socket, is prevented.

It is noted that the electric discharge devices illustrated in Figures 7 and 8 have two terminal members which are of difierent shapes and/or diameters and that the other terminal members have the same diameter. It will be readily appreciated that it is within the scope of this invention to have all of the electric discharge device terminals of differing diameters and/or shapes; however, it is generally necessary to have only two that are different in order to properly orient the electric discharge device in the socket. In the instance of an electric discharge device having a separate heater, it is generally desirable to provide at least one of the electrodes, such as anode terminals 60, with an asymmetrical shape so that the circumferential orientation of the electric discharge device in the socket is determined by the shape of the discharge device terminals; however, it will be readily appreciated that, in an alternative construction, the heater leads 76 and 77 can be brought out to two cylindrical terminals.

While the preceding disclosure describes a limited number of embodiments of this invention, by the way of example, it will be appreciated that this invention is subject to a wide variety of modifications and it is intended, in the appended claims, to cover all such modifications as come within the true spirit and scope of this invention.

What I intend to protect by Letters Patent of the United States is:

1. An electric discharge device and socket assembly comprising an electric discharge device having an envelope including substantially cylindrical metallic terminal members separated by substantially cylindrical insulating spacers, a socket adapted to receive said electric discharge device including a plurality of longitudinally spaced parallel substantially fiat conectors each provided with a spring loaded recess to receive the metallic terminal members of the discharge device, one of said connectors having a transverse dimension greater than another of said connectors to provide shielding, a base member loosely retaining said connectors whereby the connectors firmly grip the discharge device without im posing strains on the discharge device envelope, said insulating spacers having a greater transverse dimension than the corresponding dimension of the terminal memhere adjacent thereto to electrically and mechanically separate the connectors.

2. In combination, an electric discharge device having an envelope including a pair of generally cylindrical ceramic insulating members and a conductive terminal member interposed therebetween and bonded thereto and having a transverse dimension smaller than the diameter of the ceramic insulating members to provide a terminal surface recessed from the adjacent surfaces of the envelope and a socket including substantially flat conductive contact means having opposed surfaces resiliently engaging said terminal surface.

3. In combination, an electric discharge device having an envelope including alternately arranged conductive terminals and insulating spacers having generally circular exterior configurations with the conductive terminals having a transverse dimension smaller than the corresponding transverse dimension of the adjacent insulating spacers to provide an envelope wall having longitudinally spaced terminal surfaces recessed from the exterior wall of the envelope and a socket including a plurality of generally flat, parallel conductive means each having opposed portions resiliently engaging one of said terminals.

4. In combination, a generally cylindrical hermetically sealed envelope including a plurality of generally cylindrical. ceramic insulating members and a plurality of conductive terminal members alternately arranged in stacked relation with said insulating members and bonded thereto and having a transverse dimension smaller than the diameter of the adjacent ceramic insulating members to provide terminal surfaces recessed from the adjacent surfaces of the envelope and a socket including an insulating support and a plurality of substantially flat conductive contact means loosely mounted in said support in spaced relation axially along said envelope and having surfaces for resiliently engaging said terminal surfaces.

5. In combination, an electric discharge device having an envelope including alternately arranged conductive terminals and insulating spacers having generally circular exterior configurations with the conductive terminals having a transverse dimension smaller than the corresponding transverse dimension of the adjacent spacers to provide an envelope wall having terminal surfaces recessed from the exterior wall of the envelope, a plurality of electrodes within said envelope electrically coupled respectively with the conductive terminals and a socket including an insulating base and a plurality of generallyflat conductive means extending through said base having opposed portions extending from one side of said base and resiliently engaging said terminals and portions extending from the opposite side of said base and cooperating with said terminals and electrodes to provide circuits tuned to a predetermined frequency.

- 6. The combination claimed in claim 5 wherein conductive means movable in position is provided between adjacent flat conductive means on one side of said base to adjust the magnitude of said predetermined frequency.

7. In combination, an electric discharge device having an envelope including a pair of generally cylindrical ceramic insulating members and a conductive terminal member interposed therebetween and bonded thereto and having a transverse dimension smaller than the diameter of the ceramic insulating members to provide a terminal surface recessed from the adjacent surfaces of the envelope, an electrode within said envelope and connected to said conductive terminal, said conductive terminal providing an externally accessible connection for said electrode.

8. In combination, an electric discharge device having an envelope including alternately arranged conductive terminals and insulating spacers bonded together and having generally circular exterior configurations with the conductive terminals having an outside diameter smaller than the outside diameter of the adjacent insulating spacers to provide an envelope wall having longitudinally spaced terminal surfaces recessed from the exterior wall of the envelope, electrodes within said envelope and connected respectively with said conductive terminals, said conductive terminals providing externally accessible connections for said electrodes.

9. A socket adapted to receive an electric discharge device having a generally cylindrical envelope including a plurality of generally circular terminals spaced longitudinally of the axis of the device envelope and between insulating members of larger outside diameter than said circular terminals, said socket comprising a base of insulating material, a plurality of substantially flat conductive terminal members supported from and loosely retained by said insulating base and extending away from and beyond one side of said base in substantially parallel and longitudinally spaced relation, the space between said terminal members being open to receive the insulating portions of said discharge device, the extending portions of said terminal members being recessed to provide opposed terminal portions adapted to engage the terminals of said electric discharge device and support it with the axis thereof extending in the direction of the spacing of said terminal members.

10. A socket as defined by claim 9 wherein said terminal members extend from said base in the respective planes thereof in a direction opposite from the recessed portions to thereby provide at least one parallel tuned circuit. a

11. A socket as defined by claim 10 wherein electrically conductive means are provided between at least two adjacent terminal members to tune the parallel tuned circuits provided by the extensions of said terminal members.

12. An electric discharge device socket adapted to receive an electric discharge device having a generally cylindrical envelope including a plurality of generally circular terminals spaced longitudinally on the axis of the device envelope and between insulating members of larger outside diameter than said circular terminals, said socket including a base member of insulating material, a plurality of longitudinally spaced, parallel, substantially flat connectors each being recessed to provide spring loaded portions extending from and beyond one side of said base, so that the spaces between said connectors are open and the recesses in said connectors are adapted to receive the terminals of said discharge device and the spaces between the connectors receive the insulating members, one of said connectors having a transverse dimension greater than another of said connectors to provide shielding between input and output circuits coupled to the discharge device, said base member loosely retain ing said connectors whereby the connectors firmly grip the discharge device without imposing strains thereon.

References Cited in the file of this patent UNITED STATES PATENTS 1,009,386 Davis et a1 Nov. 21, 1911 1,907,968 Hunt May 9, 1933 2,043,733 Brasch et a1. June 9, 1936 2,129,725 Alden Sept. 13, 1938 2,259,739 Del Camp Oct. 21, 1941 2,397,985 Schriefer Apr. 9, 1946 2,459,272 Fox Jan. 18, 1949 2,490,110 Welch Dec. 6, 1949 2,536,011 Toth Dec. 26, 1950 2,621,226 Conron Dec. 9, 1952 2,629,066 Eitel et al. Feb. 17, 1953 2,702,376 Brush Feb. 15, 1955 2,719,185 Sorg et al. Sept. 27, 1955 2,729,801 Hesse .Jan. 3, 1956 2,760,176 Del Camp Aug. 21, 1956 FOREIGN PATENTS 282,035 Germany Feb. 12, 1915