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US2869015A - Method of fabricating a grid electrode - Google Patents

Method of fabricating a grid electrode Download PDF

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Publication number
US2869015A
US2869015A US519328A US51932855A US2869015A US 2869015 A US2869015 A US 2869015A US 519328 A US519328 A US 519328A US 51932855 A US51932855 A US 51932855A US 2869015 A US2869015 A US 2869015A
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Prior art keywords
grid
frame
assembly
turns
fusible material
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US519328A
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Alfred R Bolz
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AT&T Corp
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American Telephone and Telegraph Co Inc
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Priority to US519328A priority Critical patent/US2869015A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
    • H01J2893/0012—Constructional arrangements
    • H01J2893/0019—Chemical composition and manufacture
    • H01J2893/0022—Manufacture
    • H01J2893/0025—Manufacture by winding wire upon a support

Definitions

  • the grid laterals be relatively close together and spaced uniformly along the length of the grid. It is further advantageous that the grid laterals mounted on the grid framebe firmly secured thereto to avoid undesirable effects of electrostatic fields or mechanical vibration upon the grid pitch.
  • the thread of thin fusible material subsequently be heat treated to bond the turns of grid wire to the frame in the desired spaced relation.
  • Fig. 1 is an elevational view of an illustrative discharge device incorporating a grid assembly fabricated in accordance with this invention, a portion of the envelope and the internal structure of the device being broken away to show the grid assembly;
  • Fig. 2 is a chart showing the steps constituting a method of fabricating a grid in accordance with one specific embodiment of this invention
  • Fig. 3 is a partial elevational view of one side rod of the grid assembly after the fusible material and grid are wound prior to the final processing;
  • Fig. 4 is a perspective view of the grid in final form with the fusible material fired and the assembly prepared for insertion in the unitary electrode assembly in Fig. 1.
  • Fig. 1 discloses an' electronicdischarge device of the type in which the invention advantageously may be utilized.
  • Such device may comprise an electrode assembly including a control grid I wound about a pair of side rods 2 and 3, a screen satisfactory due to the difficulty in obtaining small spacings in the former and in utilizing high melting point metals in the latter. Further, it was a difficult and timeconsuming task with such methods to obtain an exact and uniform spacing of the grid laterals.
  • the entire electrode assembly is supported between a pair of transverse mica end spacers S and 9, the lowermost one of which is held in position by a number of support members 10 which are fixed to the inner base member 11 of the envelope 12. Electrical connection from the exterior of the envelope to the electrodes is made by the pins 13, which extend through the base of the envelope and are sealed therein, and the straps 14 extending from the pins to the various electrodes.
  • the discharge device further may include a getter 15 and an end shield 1% as shown in Fig. 1.
  • the control grid 1 of the discharge device shown in Fig. l is made up of a plurality of turnu of a fine grid wire wound on a frame which advantageously may comprise the pair of side rods 2 and 3.
  • These side rods advantageously are rigidly maintained in proper spaced relation with respect to each other by a pair of cross straps 16 and 17 located near the ends of the side rods as best seen in Fig. 4
  • the grid is fabricated in the manner shown by the chart of Fig. 2.
  • the side rods of the grid frame first are placed in a winding machine, such as is known in the art, and a helix of thin fusible material 18, which advantageously may be glass thread, is wound upon the side rods to provide the requisite number of turns per
  • the glass thread thus utilized has ing relation therewith to provide the requisite; numberof turns per lineal inch of the supporting rods.
  • the grid wire then is wound about the rods in alternate or interposed relation with the fusible material, the spaces between adjacent convolutions of the latter serving to locate the successive turns of the grid wire and determining terials used.
  • a glass having properties similar to that commerically known as Corning No. 7052 advantageously may be employed.
  • This is a borosilicate glass which is composed of the following approximate parts: silica 68.0, alumina 8.1, sodium oxide 1.9, barium oxide 2.4, lithium oxide 8.5, and boron oxide 15.2, and has a coefi'lcient of expansion substantially equal to 4.7 10" centimeters per centimeter length per degree centigrade.
  • a helix of fine grid wire then is wound about the side rods of the grid frame, the spaces betweenadjacent convolutions of the glass thread servingproperly' to locate the successive turns of the grid wire and to determine the desired number of turns per lineal inch of side rod.
  • the entire grid assembly then is heat processed, such as by placing the assembly in an electrically heated oven for a suflicient time to cause the thread of fusible material to fuse and permanently bind the turns of the grid wire to the grid frame at the desired spacing.
  • This arrangement provides an efficient assembly wherein the helicalgrid winding is relatively easily spaced and secured to the grid frame.
  • the spacing between adjacent turns of the grid wire is controlled ina simple manner l1 rality of turns of a fusible material around a frame, winding a grid wire upon said frame, said grid wire being positioned between adjacent ones of said turns, and heating said electrode assembly to cause said fusible material to secure said grid wire to said frame.
  • Fig. 3.- shows a partial view of the grid assembly com- 0 prising the side rod3, the turns of'the grid wire 1, and the turns of the fusible thread 18 prior to heating of the grid assembly to fuse the thread 18.
  • the diameters of the grid wire and the fusible thread advantageously are of the same diameter, as, for example, .001 inch each, thus enabling a grid of 500 turns per inch to be wound around the side rods in the region between the cross straps.
  • Fig. 4 shows the completed grid assembly after the heat treatment has causedthe grid laterals 1 to be fused to the side rods 2 and 3 in the desired spaced relation.
  • the grid assembly as shown is in condition to be inserted in the discharge device in the manner shown by the unitary assembly of Fig. 1.
  • a composite electron discharge grid assembly comprising a support member, a thin Wire of fusible material wound about said support in continuously contacting relation .therewithdefining positioning means on said support, and a helix of grid wire wound about said support in successively interposed relation with adjacent turns of said thin: fusible material, each turn of the helix contacting adjacent turns ofthe fusible material.
  • a composite electron-discharge grid assembly comprising a pair of side supports, a helix of thin, fusible material wound about each of said supports in continuously contacting:relation therewith, adjacent turns of said thin, fusiblematerial defining positioning means onsaid supports, means for spacing said supports apart from each other, and a helix of grid wire wound about said supports, said grid wire being interposed between adjacent turns of said thin fusible material.
  • the method of manufacturing anelectrode structure which comprises the. steps of winding a thread of fusible material abouta pair of-support members, the adjacent turns of said thread defining .a plurality of spacestherebetween, connecting a. pair of strap .memberstosaid type including a frame having a pair of side support members which comprises the steps of winding a helix of fusible material about each of said support members, said helix defining a plurality of spaces between adjacent ones of'the turns of said thin fusible material, winding a helix of grid wire upon said support members, said grid wire being'positioned in said spaces, and heating the grid assembly to cause the fusible material to fuse and bond the grid wire to said support members.

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  • Electron Sources, Ion Sources (AREA)

Description

Jan. 13, 1959 A A. R. BOLZ 2,369,015
METHOD OF FABRICATING A GRID ELECTRODE Filed July 1, 1955 FIG.
PLACE SIDE RODS IN WINDING MEANS APPLY CROSS STRAPS TO THE SIDE RODS TO FORM A RIGID GRID FRAME ASSEMBLY WIND SECOND HEL IX OF GRID WIRE AROUND THE FRAME IN THE SPACES PROVIDED BY ADJACENT TURNS OF THE FUSIBLE MATERIAL APPLY HEAT 7O GRID ASSEMBL Y TO MELT THE FUSIBLE MATERIAL AND SECURE THE GRID WINDING TO THE FRAME 3 IN PROPER SPACED 7 RELATIONSHIP FIG. 4
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INVENT'OR A. R. BOL Z A T TORNEV METHOD OF FABRICATING A GRID ELECTRODE Alfred R. Bolz, Lutherville,,Md.,. assignor to American Telephone and Telegraph Company, a corporation of New York Application July 1, 1955, Serial No. 519,328 9 Claims. (Cl. 313-350) The invention relates to space discharge devices and more particularly to a grid assembly and its method of fabricating such devices.
The operating requirements of many present-day types of space discharge devices are such that in these devices there must be an extremely precise mechanical correlation of the elements of the electrode assembly involved. Some desirable characteristics, such as hightransconductance and low noise, are directly dependent upon the reliability of the spacing of the control grid wires with respect to each other and with respect to the other electrodes of the assembly. I
In discharge devices designed to operate in the higher frequency ranges, for example, in order to secure the desired controlling action upon the electron stream needed for high values of transconductance, it is advantageous that the grid laterals be relatively close together and spaced uniformly along the length of the grid. It is further advantageous that the grid laterals mounted on the grid framebe firmly secured thereto to avoid undesirable effects of electrostatic fields or mechanical vibration upon the grid pitch.
The above-recited conditions have presented some rather difiicult mechanical problems in the prior art of grid fabrication. Such well-known methods of spacing and securing grid wires to a frame as notching and swaging or using welded metal joints have not proved entirely In accordance with a feature of this invention, a thread of thin fusible material is wound upon the support rods of a grid frame to enable the turns of a grid Wire to be easily and properly located thereon in adesired spaced relation to one another.
It is a further feature-of this invention that the thread of thin fusible material subsequently be heat treated to bond the turns of grid wire to the frame in the desired spaced relation.
A complete understanding of this invention, together with the above-noted and other features thereof, may be gained from consideration of the following detailed description and the accompanying drawing, in which:
Fig. 1 is an elevational view of an illustrative discharge device incorporating a grid assembly fabricated in accordance with this invention, a portion of the envelope and the internal structure of the device being broken away to show the grid assembly;
Fig. 2 is a chart showing the steps constituting a method of fabricating a grid in accordance with one specific embodiment of this invention;
Fig. 3 is a partial elevational view of one side rod of the grid assembly after the fusible material and grid are wound prior to the final processing; and
Fig. 4 is a perspective view of the grid in final form with the fusible material fired and the assembly prepared for insertion in the unitary electrode assembly in Fig. 1.
Referring now to the drawings, Fig. 1 discloses an' electronicdischarge device of the type in which the invention advantageously may be utilized. Such device may comprise an electrode assembly including a control grid I wound about a pair of side rods 2 and 3, a screen satisfactory due to the difficulty in obtaining small spacings in the former and in utilizing high melting point metals in the latter. Further, it was a difficult and timeconsuming task with such methods to obtain an exact and uniform spacing of the grid laterals.
t It is an object of this invention to provide an improved method of fabricating grid assemblies for space discharge devices wherein the turns of a grid wire may be accurately and relatively easily spaced and secured on a grid frame.
It is a further object of this invention to enable utilization of the means for initially. spacing the grid wire turns subsequently for securing the turns to the grid frame in a desired spaced relation to each other.
illustrative embodiment of this invention in which the side rods of the grid frame structure are wound with a helix of a thin fusible material in continuously contact- .55 It is a still further object of this invention to realize lineal inch of side rod.
grid 4 surrounding the control grid l and wound about a pair of side rods 5 and 6, and an anode 7. The entire electrode assembly is supported between a pair of transverse mica end spacers S and 9, the lowermost one of which is held in position by a number of support members 10 which are fixed to the inner base member 11 of the envelope 12. Electrical connection from the exterior of the envelope to the electrodes is made by the pins 13, which extend through the base of the envelope and are sealed therein, and the straps 14 extending from the pins to the various electrodes. The discharge device further may include a getter 15 and an end shield 1% as shown in Fig. 1.
The control grid 1 of the discharge device shown in Fig. l is made up of a plurality of turnu of a fine grid wire wound on a frame which advantageously may comprise the pair of side rods 2 and 3. These side rods advantageously are rigidly maintained in proper spaced relation with respect to each other by a pair of cross straps 16 and 17 located near the ends of the side rods as best seen in Fig. 4
In accordance with one embodiment of this invention, the grid is fabricated in the manner shown by the chart of Fig. 2. The side rods of the grid frame first are placed in a winding machine, such as is known in the art, and a helix of thin fusible material 18, which advantageously may be glass thread, is wound upon the side rods to provide the requisite number of turns per In accordance with a further aspect of this invention, the glass thread thus utilized has ing relation therewith to provide the requisite; numberof turns per lineal inch of the supporting rods. ,The grid wire then is wound about the rods in alternate or interposed relation with the fusible material, the spaces between adjacent convolutions of the latter serving to locate the successive turns of the grid wire and determining terials used. a
the desired number of turns per lineal unit. The entire-..
assembly then is heat treated to fuse the fusible, helix material sufficiently to bond the turns of the grid wire securely in the desired position.
a coeflicient of expansion matching that of the grid ma- For example, in the specific illustrative embodiment shown in Figs. 3 and 4 of the drawing, wherein the grid is of tungsten and the frame side rods of molybdenum, a glass having properties similar to that commerically known as Corning No. 7052 advantageously may be employed. This is a borosilicate glass which is composed of the following approximate parts: silica 68.0, alumina 8.1, sodium oxide 1.9, barium oxide 2.4, lithium oxide 8.5, and boron oxide 15.2, and has a coefi'lcient of expansion substantially equal to 4.7 10" centimeters per centimeter length per degree centigrade.
In accordance with one specific embodiment of this invention, a pair of cross straps 16 and 17, which advantageously may be comprised of molybdenum, is then fastened to the ends 'of the side rods providing a rigid and unitary grid frame structure. A helix of fine grid wire then is wound about the side rods of the grid frame, the spaces betweenadjacent convolutions of the glass thread servingproperly' to locate the successive turns of the grid wire and to determine the desired number of turns per lineal inch of side rod.
The entire grid assembly then is heat processed, such as by placing the assembly in an electrically heated oven for a suflicient time to cause the thread of fusible material to fuse and permanently bind the turns of the grid wire to the grid frame at the desired spacing.
This arrangement provides an efficient assembly wherein the helicalgrid winding is relatively easily spaced and secured to the grid frame. The spacing between adjacent turns of the grid wire is controlled ina simple manner l1 rality of turns of a fusible material around a frame, winding a grid wire upon said frame, said grid wire being positioned between adjacent ones of said turns, and heating said electrode assembly to cause said fusible material to secure said grid wire to said frame.
3. The method of spacing a grid wire on a frame in an electrode assembly comprising thesteps of winding a helix of a fusible material on said frame to provide a desired number of turns per lineal unit of said frame, and winding ahelix of grid wire on said frame in the spaces between adjacent convolutions of the fusible material to space properly successive turns of said grid wire.
4. The methodof spacing a grid wire on a frame in I an electrode assembly in accordance with claim 3 further through the choice of a thread of fusible material of proper diameter. Furthermore, the heat treatment incidental to the fusing process is notseriously detrimental to the tension stress of the fine grid wire or the frame structure. since these components advantageously are highly refractory metals, thus resulting in very little loss in the residual tension. 1
Fig. 3.- shows a partial view of the grid assembly com- 0 prising the side rod3, the turns of'the grid wire 1, and the turns of the fusible thread 18 prior to heating of the grid assembly to fuse the thread 18. In accordance with an aspect of the invention the diameters of the grid wire and the fusible thread advantageously are of the same diameter, as, for example, .001 inch each, thus enabling a grid of 500 turns per inch to be wound around the side rods in the region between the cross straps.
It can now t be seen that due to the advantages obtained by this highly efficient method of construction grids having very close spacings may be constructed with sufiiciept precision to satisfy the electrical characteristics required in present;
day discharge devices.
Fig. 4 shows the completed grid assembly after the heat treatment has causedthe grid laterals 1 to be fused to the side rods 2 and 3 in the desired spaced relation. The grid assembly as shown is in condition to be inserted in the discharge device in the manner shown by the unitary assembly of Fig. 1.
Whilethis invention has been disclosed in a particular embodiment and method of operation, it will be undercomprising the step of heating the frame for a sufficient time to cause the fusible material to bond the grid wire to the frame in the desired spaced relation.
5. A composite electron discharge grid assembly com. ,prising a support member, a thin Wire of fusible material wound about said support in continuously contacting relation .therewithdefining positioning means on said support, anda helix of grid wire wound about said support in successively interposed relation with adjacent turns of said thin: fusible material, each turn of the helix contacting adjacent turns ofthe fusible material.
6. A .composite electron discharge grid assembly in accordance with claim 5, wherein said helix of thin, fusible material has a-coefiicient of thermal expansion substantially equal to that of said support member and grid wire.
7. A composite electron-discharge grid assembly comprising a pair of side supports, a helix of thin, fusible material wound about each of said supports in continuously contacting:relation therewith, adjacent turns of said thin, fusiblematerial defining positioning means onsaid supports, means for spacing said supports apart from each other, and a helix of grid wire wound about said supports, said grid wire being interposed between adjacent turns of said thin fusible material.
8. The method of fabricating a grid assembly for space discharge devices which comprises'the steps of winding a helix of a fusible material around each of a pair of support members, securing a plurality of cross straps to said pair of support members to form a rigid frame assembly,
- winding a helix of grid wire around said frame assembly,
stood by those skilled in the art that various modifications may be made in the materials, shape of grid frame, winding method and processing to achieve the results of the invention.
What is claimed is:
1. The method of fabricating a grid assembly of the said grind wire being'positioned by the adjacent turns of a said fusible material, and heating the:frame assembly to fuse said fusible material and secure the grid wire to the supportmembers inthe desired spaced relation.
9. The method of manufacturing anelectrode structure which comprises the. steps of winding a thread of fusible material abouta pair of-support members, the adjacent turns of said thread defining .a plurality of spacestherebetween, connecting a. pair of strap .memberstosaid type including a frame having a pair of side support members which comprises the steps of winding a helix of fusible material about each of said support members, said helix defining a plurality of spaces between adjacent ones of'the turns of said thin fusible material, winding a helix of grid wire upon said support members, said grid wire being'positioned in said spaces, and heating the grid assembly to cause the fusible material to fuse and bond the grid wire to said support members.
2. The method of fabricating an electrode assembly for space discharge devices comprising winding a plusupport members to form an integral frame assembly, winding a plurality of turnsof grid wire around said frame assembly, said grid wire beingpositioned. in the spaces defined by the turns of said thread, and heating a the frame assembly to causesaid thread tofuse and bond the grid wire to said support members.
References Cited in the file of this patent UNITED STATES PATENTS
US519328A 1955-07-01 1955-07-01 Method of fabricating a grid electrode Expired - Lifetime US2869015A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3404442A (en) * 1966-04-20 1968-10-08 Rca Corp Method of fabricating directly heated cathode
US3500534A (en) * 1966-02-23 1970-03-17 Hughes Aircraft Co Method of making a slow-wave structure encasement

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1340575A (en) * 1917-09-04 1920-05-18 Cutler Hammer Mfg Co Electroionic valve
US1957223A (en) * 1928-09-25 1934-05-01 Gen Electric Grid electrode
US2224214A (en) * 1937-12-28 1940-12-10 Polaroid Corp Light polarizing body
US2501002A (en) * 1946-10-26 1950-03-21 Sylvania Electric Prod Control grid
US2790926A (en) * 1951-01-27 1957-04-30 Bell Telephone Labor Inc Traveling wave tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1340575A (en) * 1917-09-04 1920-05-18 Cutler Hammer Mfg Co Electroionic valve
US1957223A (en) * 1928-09-25 1934-05-01 Gen Electric Grid electrode
US2224214A (en) * 1937-12-28 1940-12-10 Polaroid Corp Light polarizing body
US2501002A (en) * 1946-10-26 1950-03-21 Sylvania Electric Prod Control grid
US2790926A (en) * 1951-01-27 1957-04-30 Bell Telephone Labor Inc Traveling wave tube

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3500534A (en) * 1966-02-23 1970-03-17 Hughes Aircraft Co Method of making a slow-wave structure encasement
US3404442A (en) * 1966-04-20 1968-10-08 Rca Corp Method of fabricating directly heated cathode

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