US2492162A - Method and apparatus for sealing electrodes in envelopes of electron discharge tubes - Google Patents

Description

Dec. 27, 1949 c. v. LITTON 2,492,162

METHOD AND APPARATUS FOR SEALING ELECTRODES IN ENVELQPES OF ELECTRON DISCHARGE TUBES Filed May 15, 1946 4 Sheets-Sheet 1 S L l2 INVENTOR CHARLES V LITTON W Z' ATTO M Dec. 27, 1949 c. v. LITTON 2,492,162

METHOD AND APPARATUS FOR SEALING ELECTRODES IN ENVELOPES OF ELECTRON DISCHARGE TUBES Filed May 15, 1946 4 Sheets-Sheet 2 I'III: 9 ,u 40 25 42 INVENTOR CHARLES v. LlTTON BY- z:

ATTORN EY Dec. 27, 1949 c. v. LITTON METHOD AND APPARATUS FOR SEA 2,492,162 LING ELECTRODES IN ENVELOPES OF ELECTRON DISCHARGE TUBES 4 Sheets-Sheet 3 Filed May 15, 1946 INVENTOR CHARLES V. LITTON ATTORNEY Dec. 27, 1949 c, v, Lrr 2,492,162

METHOD AND APPARATUS FOR SEALING ELECTRODES -IN ENVELOPES 0F ELECTRON DISCHARGE TUBES Filed May 15, 1946 4 Sheets-Sheet 4 INVENTO CHARLES V LITT BYZ ATTORNEY Patented Dec. 27, 1949 mz'rnon AND APPARATUS FOR SEALING amoraonas nv ENVELOPES F ELEC- raon' DISCHARGE TUBES 'Charles V. Litton, Redwood City, Calif., assignor to Federal Telephone and Radio Corporation, New York, N. Y., a corporation of Delaware Application May 15, 1948, Serial No. 889,803 10 Claims. (Cl. 29-1795) 1 This invention relates to electrode supports and lead-in terminals for electron discharge devices and to the method and apparatus for assembling .and attaching an electrode support to the wall of an electron discharge device so as to provide a connecting terminal for the electrode through the wall of said device.

One of the objects of the invention is to provide a rigid support for an electrode of an electron discharge device which may be attached to the wall of the envelope thereof.

Another object of the invention is to provide an electrode support as defined in the above paragraph which at the same time forms a terminal connection for the electrode through the wall of the envelope of the electron device.

Still another object of the invention is to provide a method and an apparatus for assembling and attaching an electrode support to the wall of an electron discharge device envelope.

Other objects of the invention and objects relating particularly to the construction and assembly of the various parts forming the electrode support and terminal will be apparent as the description of the invention proceeds.

The invention is illustrated in the accompanying drawings in which:

Fig. 1 is a sectional side elevation of one end of an envelope of an electron discharge device showing the electrode support assembly in position just before attaching to the envelope wall;

Fig. 2 is a fragmentary sectional view of the electrode support assembly attached to the wall of the envelope;

Fig. 3 is an elevational view partly in section of an apparatus for attaching the improved electrode support and terminal to the wall of the envelope;

Figs. 4 and 5 are bottom plan and side elevational views, respectively, of the electrode support;

Fig. 6 is a perspective view of a portion of the assembling machine showing the manner of holding the electrode support in position for incorporating into the discharge device;

Fig. 7 is a perspective view of the lathe chuck for supporting the neck of the envelope of the electron discharge device showing the movable bracket for holding the electrode support;

Fig. 8 is a sectional side elevation of the portion of an electrode support employed in accordance with my invention;

Fig. 9 is a sectional side elevation of a portion of the apparatus for forming an electrode support employed in accordance with my invention;

Fig. 10 is a sectional side elevation of a portion of the forming apparatus and the formed electrode support employed in accordance with my invention;

Fig. 11 is a schematic diagram showing a modifled arrangement for reciprocating the assembled electrode support and terminal during the process of sealing it into the wall of the envelope.

Referring now to the several figures the invention has been disclosed in connection with a high power vacuum tube the envelope of which has a cylindrical glass portion I flared at one end, as at 2, for attachment to another portion of the envelope (not shown) which may be the anode of the tube. The other end of the cylindrical portion I of the envelope is adapted to be attached to a base (not shown) which forms a support and provides a lead-in for the cathode of the tube, the cathode extending through the cylindrical portion I and into the anode portion of the envelope. The arrangement of the anode and cathode of the tube form no part of the present invention which is concerned chiefly with the support for the grid element.

The grid support 3, according to the present invention, comprises a ring 4 of suitable metal provided with a right angular extension 5 by means of which the support is attached to the terminal pin 6 which extends from the wall of the envelope and forms a connecting terminal for the grid of the tube. In order to give the support 3 sufficient strength'for its purpose and at the same time stamp it out of thin metal the ring portion 4 of the support is given a channel cross section and the angular extension 5 is provided with flanged edges, as indicated. These flanged edges extend along the sides of the extension 5 but terminate just short of the rounded end of the extension. Reinforcing braces l are welded between the extension 5 and the ring 4.

The grid (not shown) is supported within the anode and may be mounted upon support rods 8 which are welded or otherwise attached to the ring portion 4 of the grid support 3.

The extension 5 of the grid support 3 is'provided with a hole 9 which is adapted to fit over a cylindrical portion ID of a cup-shaped member II which is adapted to be sealed into an opening I2 in the cylindrical wall I of the envelope in a manner to be later described. The hole I2 may be formed in any desired manner as by the known method of punching while the glass is hot and the edges thereof are upturned, as clearly indicated in Fig. 1. The terminal pin 6 is shaped like a nail havinga head I3 which is of the proper diameter to fit into the cylindrical portion ill of the cup-shaped member II. The extension I the support 3 is welded to the cup-shaped member II and the head I3 of the terminal pinis also welded within the cylindrical portion It so that the support 3, the cup-shaped member II, and the'term'inal pin 6 form a rigid unitary member when properly welded together. The manner in which this is done is described in detail in my copending application Ber. No. 515,268, filed December 22, 1943, now Patent No. 2,452,582, granted November 2, 1948. To provide a better understanding of my present invention, I shall briefly describe the method of forming the electrode support described in detail in the copending application.

First, it is desired to assemble the grid support 2 the cup-shaped member II, and the terminal pin in a temporary manner preparatory to the flnal welding or fusing operations. This operation is preferably performed in a punch press indicated in Figs. 9 and 10, having a stationary die member It over which the cup-shaped member II may be positioned, the cup-shaped member being provided with a shoulder I5 to position it upon the die member It in such a manner that the outer rim will be spaced from the die member. The die member I4 is provided with a central bore it into which the pin 5 may be inserted, and this bore is provided with a piston Il urged upwardly by a spring I8 to keep the head of the terminal pin 5 against the cup-shaped member during the assembling operation.

Preferably, prior to the assembling of member II with extension 5 and pin 6, the cup-shaped member II is provided with a ring of glass I9 which is fused to the tapered edge of the cupshaped member, as shown in Fig. 8. This is for the purpose of more readily fusing the cupshaped member II to the glass around the opening I2 in the cylindrical portion I of the envelope.

The terminal pin 5 is now inserted in the opening I6 of the die member It with the head I3 protruding from the top thereof. A disc 2I of silver solder or other brazing or soldering material is then placed on the top of the head I3, and the cup-shaped member I I is then placed over the die member I3 with the head of the terminal pin extending into the cylindrical portion In of the cup-shaped member. A washer 22 of silver solder or other brazing or soldering material may then be placed over the top of the cylindrical member III, the diameter of the hole in the washer being sufiicient for the washer to fit easily over the cylindrical member. Then the electrode support 3 is applied by slipping the extension 5 over the cylindrical member Ill.

The punch press is provided with a cooperating die member 23 which is the same diameter or a little larger than the diameter of the cylindrical member ID, and this die I lember 23 is then brought downwardly in the direction of the arrow upon the top of the cylindrical member I0. When pressure on the die member 23 is applied, the cylindrical member II) will start to deform, bulging outwardly at the top over the extension 5 of the support 3 and bulging inwardly under the head I3 of the terminal pin 6. It will be seen that this crimping action holds the cup-shaped member, the terminal pin, and the electrode support in physical gripping contact with each other and with the washer 22 and disc 2 I of silver solder in position so that when heat is applied these parts can be fused together.

The manner in which this unitary structure 4 comprising the terminal pin, the up-shaped member, and the electrode support held in physical gripping contact with each other and with the washer 22 and disc 2| of silver solder in position as shown in Fig. 10 is such that when heat is applied these parts can be fused together.

The manner in which this unitary structure comprising the terminal pin, the cup-shaped member, and the grid support (which may have the grid already attached to it by means 0! the support rods 3) is fused into the wall 01' the envelope and the metal parts soldered or welded together in a single operation will now be described.

In order to position the parts properly for the assembling operation I provide a lathe chuck 24 for receiving the cylindrical end I of the glass envelope, a suitable contact members 25 being provided for gripping the glass without breaking it. The envelope I is positioned in this lathe chuck with the hole I2 in the cylindrical wall at the lower side. The lathe chuck 2| is rigidly supported upon an angle bracket 23 which is in turn mounted upon a table 21, so that when the envelope I is positioned in the lathe chuck, it is fixed with respect to the table and does not move in any direction or rotate.

It is desired to position the electrode support assembly within the envelope for the fusing and welding operation in such a manner that it can have a limited vertical movement with respect thereto for a purpose to be hereinafter described. To this end a plate 23 (Figs. 3, 6, and 7) is provided mounted on the back of the bracket 25 within guides 29 and ill so that it can be moved vertically. A rod 3| is mounted upon the plate 28 by means of the screw 32, and this rod extends outwardly through an opening '33 in the bracket 26 and through the lathe chuck and the tubular portion I or the envelope, terminating Just beyond the opening I2 in the envelope. At the end of this rod 3| is provided a plate 34 upon which the ring 4 of the electrode support 3 may be temporarily mounted. This mounting may be accomplished by means of a plurality of clips 35, pivotally mounted, one at each corner of the plate, which may be rotated by hand to have engagement with the ring portion I of the electrode support. When thus properly mounted on the plate 34 the electrode support assembly assumes the position shown in Figs. 1, 3, and 6 with the cup-shaped member II just above the inwardly flared adges of the opening I2 in the envelope and with the terminal pin 6 extending downwardly through the opening I2. I may prefer to place the electrode support assembly in position before the envelope is placed in the chuck, but the envelope may be positioned first, if desired. The alignment of the hole I2 and the cup-shaped member II may be assured by accurately positioning the hole in the cylindrical portion I of the envelope and accurately positioning the envelope in the lathe chuck.

In order to raise and lower the grid support assembly the plate 28 is provided with a rack 35 which is arranged to mesh with a gear wheel 31 rotatably mounted upon a bracket 38 secured to the bracket 26 in any desirable manner. Another gear wheel 39 is also rotatably mounted on a suitable stub shaft 40 on the bracket 33 and is arranged to mesh with the gear 31. The end of the shaft 40 may be provided with a hand wheel I which may be rotated by the operator to raise and a lower the electrode support assembly.

with a burner 48 at the and means to rotate it'and intocooperative'relation with through supported in the chuck.

A bearing 4! is provided for the pipe permitting it to rotate aboi tjts own axis and at the same time permitting axial movement within the bearing. The pipe is rotated by means of a motor 4' supported on the table upright which drives auxiliary shaft 41 journaledin a bearing 48 also supported on the table upright. Thelghaft 41 carries a pulley 4! over which a belt ll thebeltalso assingaroundapulleyii securedto the pipe 42. Operation of the motor will continuously drive the pipe in one direction.

The lower end of the pipe is provided with a rotary connection I! 'tovwhich the gas is supplied by a rubber hose '3. The rotary connection 8! permits the pipe 42 to rotate without disturbin the gas connection.

Means is provided for raising and loweringthe pipe by means of a foot pedal I4 which is attached to the end of a lever 65 pivotally mounted on a bracket 5! attached to the floor under the table 21. The'lever II is connected by means of a link 51 to the end of another lever I4 pivotally mounted to a bracket it secured to the floor. The

end of the lever 58 is bifurcated and straddles the pipe 42' being positioned thereon between two bearing members II. It will be seen that when the foot pedal 54 is depressed the pipe 42 will be raised without interfering with the supply of tion thereof owing to the flexibility of the belt II. A stop member I may be attached to the floor to limit the movement of the foot pedal and thus limit the movement of the burner 43 with respect to the envelope i.

The burner 43 is cross sectioned in Fig. 1 and comprises a cylindrical member with a conical upper face 0: which is internally threaded to permit screwing it on the end of the pipe 42. The burner 43 has a central extension It provided with a bore 04 to receive the terminal pin 6 when the burner is pushed up to a point near the cupshaped member Ii. Holes I in the burner head communicate with the interior of the pipe 42 and the flames It are produced at the conical The burner 43 is of sufficient diameter to fit into the cup-shaped member so that the flames will be directed against the entire interior surface as well as against the edge of the hole I! in the envelope i.

For incorporating the electrode support'into the envelope the parts are first assembled as already described and the unitary structure comprising the cup-shaped member Ii. the terminal pin 6 and the electrode support 3, with the grid structure attached thereto by means of the support rods I is mounted upon the plate 34 by means 6 shaped member and the edge of the hole It. When the burner is raised so that it extendsinto the cup-shaped member, the pin I will pass into the bore 64 in the burner. I

As soon as the glass at the edge of the hole I! and in the ring ll attached to the edge of the cup-shaped member has' been raised to fusing temperature and the metal parts have been heated so as to fuse the solder disc 2! and washer 22 the hand-wheel 4i may be rotated so as to bring the assembly down towards the 'wall of the envelope so that the glass ring it touches the glass around the edge of the hole l2. As the glass fuses together, it is preferable to oscillate the handwheel 4i several times so as to raise and lower the electrode assembly through a limited distance and thereby puddle the glass to form a better fusing connection. The foot pedal is then raised,

thus lowering the burner away from the connection.

A pair of marks 01 and .4 may be provided on the plate 28 and angle bracket 26, respectively,

' surface of which is pivoted a link ll which is in 7 gas thereto and without interfering with the rotaturn pivoted to an arm I4 attached to the gear I have provided apparatus for attaching an electrode support to the glass wall of a vacuum tube envelope which is simple and easily constructed. Also, the assembly of the support with the envelope may be quickly and easily accomplished without any partciular skill being required.

Modifications may occur to those skilled in the art and the invention is not intended to be limited except by the limitations of the appended claims.

What is claimed is:

1. The method of incorporating an electrode support having an inner support member, an outer terminal member, and an intermediate member, into an electron discharge device having an envelope with at least a portion of the wall thereof of insulating material and said portion provided with a hole therethrough having a size and shape conforming to those of said intermediate member, which comprises first assembling the said members in their desired position with respect to each other, separated only by pieces of welding material, and temporarily securing said members in said position, then positioning the thus-secured members within said envelope in approximately the desired position, with said outer terminal member extending through the hole in said envelope wall and the outer edges of said intermediate member adjacent the edges of said hole, and subsequently heating said members and saidenvelope wall at the edges of said hole lesoassimultaneouslytoweldsaidmembersto- 2. The method according to claim 1 which ineludes the prior step or fusing a ring or insulatim material around the edge of the intermediate member before positioning the temporarily secured members within the envelope, to facilitate fusing "-ldimember to the envelope wall.

3. Apparatus for mounting an electrode support assembly inan opening in the side wall of an open-ended envelope or an electron discharge device which comprises a chuck having a hollow portion adapted to receive and grip a part of 'said envelope adjacent an open end thereof for supporting the envelope in fixed position, an arm mounted for reciprocation within and relative to said hollow portion of said chuck and extending into said open end of the envelope, means to mount said electrode support assembly on the inner end of said arm with a portion of said assembly extending through said opening in the side wall and means movably mounted on said envelope supporting means andsupporting said arm within said hollow portion of said chuck to move said arm transversely with respect to said envelope supporting means so as to move said electrode assembly with respect to said side wall.

4. Apparatus according to claim 3 in which there is further provided means simultaneously to heat said assembly and side wall adjacent to the opening therein.

5. Apparatus according to claim 3 in which the means to move the arm holding the electrode support assembly comprises a member attached to said arm and slidably mounted with respect to said chuck, a rack secured to said slidable member, a pinion engageable with said rack, a crank structure coupled to said pinion, and a motor coupled to said crank structure, whereby said arm and the assembly mounted thereon is caused to reciprocate through a limited distance with respect to the wall of the envelope.

6. Apparatus for mounting an electrode support assembly in an opening in the side wall of an open-ended envelope of an electron discharge device comprising a chuck adapted to receive and grip a part of said envelope'adjacent an open end thereof for holding the envelope in a fixed position, said chuck having an opening through the center thereof, means for fixedly supporting said chuck, an arm extending through the opening in said chuck and into said open end of the envelope, means to'mount said electrode support assembly on the end of said arm adjacent said opening in the side wall with a portion of said assembly extending through said opening in the 'side wall and means movably mounted on said chuck supporting means to move the said arm laterally with respect to said chuck so as to move said electrode support assembly with respect to said opening in the side wall of said envelope.

7. Apparatus for mounting an electrode support assembly in an opening in the side wall of an open-ended envelope of an electron discharge device comprising a chuck adapted to receive and grip a part of said envelope adjacent an open end thereof for holding the envelope in a fixed position, said chuck having an opening through the center thereof, means for fixedly supporting said chuck, an arm extending through the opening in said chuck and into said open end of the envelope, means to mount said electrode support assembly on the end of said arm adjacent said opening in the side wall, and means to move said arm laterally with respect to said chuck so as to move said electrode support assembly with respect to said opening in the side wall of said envelope comprising a member slidably mounted with respect to said chuck for movement substantially at right angles to the axis of said chuck and means to move the said member to move the arm within the envelope laterally with respect to said chuck.

8. Apparatus for mounting an electrode support assembly in an opening in the wall of an open-ended envelope of an electron discharge device which comprises a chuck adapted to receive and grip a part of said envelope adjacent an open end thereof for supporting said envelope, a base member to'which said chuck is attached for supporting said chuck in fixed position, said chuck and base member having axially aligned openings therein, a plate slidably mounted upon said base member for limited movement in a direction at right angles to the axis of said chuck, an arm mounted on said plate and extending through the openings in said chuck and base member and into the cylindrical portion of said envelope,-means at the inner end of said arm toretain said electrode support assembly thereon so thata portion of said assembly is positioned adJacent the opening in said side wall, a rack secured to said plate, a pinion meshing with said rack, and means torotate said pinion so as to move said arm and electrode support assembly within said envelope laterally with respect to said chuck. I

9. Apparatus according to claim 6 in which there is further provided meanssimultaneously to heat said assembly and side wall adjacent the opening therein.

10. The method according to claim 1 in which is provided the additional steps of moving the unitary structure of said members towards the envelope wall to contact said outer edges of the intermediate member with thematerial of said wall adjacent said hole when the material of said wall adjacent said hole is at fusing temperature, and moving said unitary structure away from and towards the envelope wall while the outer edges of said intermediate member remain in contact with the material of said wall adjacent said hole, whereby there is insured a more perfect bonding between the intermediate member and envelope wall.

CHARLES V. LITI'ON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date

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