US1886991A - Filament support - Google Patents

Description

' Nov. 8, 1932. VAN HORNE 1,886,991

FILAMENT SUPPORT Filed March 29, 1926 W bm%w filil W fitter nut Patented Nov. 8, 1932 I V STATES PATENT OFFICE ,J'OHN' s. VAN HORNE, or FRANKLIN, OHIO, ASSIGNOR 'ro RADIO CORPORATION or AMERICA, A coRPonArro voP DELAWARE FILAQMEN'I SUPPORT Application fil ed March 29, nae.v Serial No. 98,166.

' My invention relates to electron discharge tension "against the edges of the interposed 'devic'es embodying filamentary electrodes and 'mica bridge to dampen the vibration. lVhile more particularly to thermionic valves or other materials may be employed, and other radio tubes, the purpose being to eliminate means of supporting the filament or holding microphonic noises by minimizing the vibrait against vibration may be utilized, the mica tion-ofthe electrode filament. bridge is preferred, since it not only aifords While the microphonic noises reproduced a high dielectric resistance, but is also low in the head phones or loud speaker units of in heat conductivity, and therefor will have aradio recelving set may to some extent be a minimum cooling effect, uponthe filament induced by other elements of a thermionic causing minimum dissipation and thereby but Valve or radio tube, it has been found by Slightly, if at all, affecting the emission of experiment and research that such noises are electrons. p 5 caused primarily by vibrations of the heated With the above primary and other incifilament or electron emitting element, which dental objects in View as will more fully 15 b cau of it fragile at re is suallymor appear in the specification, the invention co nor 'less flexibly or loosely mounted and is sists of the features of construction, the parts -highly susceptible tovibratory motion. The and combinations thereof, and the mode of hum or ringing sound'produced by such vibra- Operation or their equivalents as hereinafter tion is greatly magnified and augmented by described and set forth in the claims.

20 the radio receiving apparatus and is finally Referring to the accompanying drawing, reproduced as a harsh discordant and dis- Fig. 1 is a perspective view of an, assembled gr abl oi I r I thermionic valve or radio tube, with oneside I In the present invention, the elimination of the anode or plate elementremoved, Fig.2 or at least, the minimizing of such obj ection- [Is an enlarged vertical sectional View at right 25 able noises Y is contemplated by supporting angles to the plane of view of Fig. 1. Figs. 3, the electrode filament at one or more inter- 4 and 5 illustrate different methods of supmediat'e points, thereby dampening the viporting or dampening electrode filaments of bration of the filament or dividing the filathe hair-pin type. Figs. 6, 7 and 8 illustrate ment into two or more sections of reduced further modifications, more particularly as 30 length, which will not respond to vibration, pplied to single strand filaments.

or if vibration should occur, it will be at Like parts are indicated by similar characsuch rate as to be inaudible. As a conventers of reference throughout the several ient andeconomical embodiment of the inviews. vention for commercial producti0n,it is pr'e- In the preferred form of embodiment illusferred to provide a support or bridge of thin trated in the drawing, 1 is, the bulb or mica, which engages with the filament at a envelope of a thermionic valve of which 2 mid-length point. In the usual and popular is the press or stem, supporting the several assembly of thermionic valves or radio tubes, elements. Connected with conductors 3 into wherein is employed an electrode filament of the press 2, is an electron emitting electrode the hair-pin type surrounded by a grid ele- 0r filament 4, of inverted V shape or hair-pin ment on opposite sides of which'extend the type, the bight of which is supported by anplate or anode elements, it is preferred to anchor arm 5 also supported by the press 2. interpose such dampening bridge of mica or Surroundingthe electron emitting element 4 the like, intermediate the reverse strands of is a helical winding 6 of fine wire supported the hair-pin filament, and extending in transupon upright fingers or standards 7 and verse relation through the grid element and forming the grid element. Enclosingthe abutting upon the plate or anode element grid and filament is an anode or plate element on opposite si'desthereof. The mica bridge 8, usually formed in two interconnecting or support is of such size as to slightly spread plates, extending on opposite sides the grid I 50 the strands of the filament causing suflicient element, and supported upon arms 9, one of which is continuous through the press 2, for electrical connection of the plate into an electrical circuit, as is also one of the supporting fingers or standards 7 of the grid element. The anchor arm 5 of the electron emitting filament 41 is quite fine and flexible in order to yieldingly support the filament against breakage by shock and also to accommodate expansion and contraction of the filament. This flexible mounting necessary for the preservation of the fragile filament is more or less directly responsible for the noise inducing vibration.

To minimize the vibration of the filament without subjecting the filament to undue tension, a spreader 10 of preferably electrically and also thermally insulating material is interposed between, the strands of filament 4. This bridge or spreader 10 is preferably a small rectangularvpiece of thin mica. The spreader 10 extends transversely through the grid element, intermediate successive turns or convolutions of the grid wire 6, and is of such length as to abut upon the inner faces of the plate or anode element 8 at the opposite ends. The width of the spreader or bridge 10 is suficient that the filament strand will rest against the edges of the bridge or support, with only such pressure to arrest their vibration. The portions of the strand at opposite sides of'the bridge or support are usually thrown slightly out of alignment or are very slightly angular one to the other. This bridge or support 10 is quite thin and very light and easily supported in its adjusted position, in which it is held against lateral movement in one direction, by its terminal abutment upon the inner faces of the plate element 8, and against movement transversely by its engagement with the filament strand 4:. It is supported vertically by the helically wound wire 6 of the grid element. Being thus disposed it braces the filament 4 against undue vibration and if any vibrations occur, it is in the shortened length of filament above and below the bridge or support, the rate of vibration of which is such as to be inaudible if it does occur, the length of such sections being so short as to be normally unresponsive to vibratory tendencies. The bridge or support is located at approximately the mid-length point of the filament strand, although it need not be exactly so located. If so located as to divide the filament strand into unequal sections, they will not only produce a high vibratory rate, if vibration should be in duced, but being unequal, they will possess different vibratory rates, and tend to neutralize each other. In the case of extremely long filaments or strands, two or more rests or supports 10'" may be provided as shown in Fig. 6. In any event, the filament is restricted to a succession of comparatively short sections or lengths, which are not readily susceptible to vibration, but in which if vibration should be induced, it would occur in such frequency as to be inaudible.

Various methods of supporting the filament to arrest or minimize vibration may be employed. In Fig. 3, the support or rest has been shown provided with spaced holes 11, through which the filament strands a extend. In Fig. 4, the rest or bridge is shown provided with marginal notches 12, in which the filament strands engage. In Fig. 5 there is shown a modified construction, where in lieu of a spreader or bridge member interposed between the strands of the electrodes, each filamentstrand is separately supported by a tie 13 of insulating material medially connecting the filament strand with the spaced standards or supporting fingers 6 of the grid element. Figs. 6 and 7 show the damping support applied to a single strand filament, which may either bear against the marginal edge ofsuch support or rest as shown in Fig. 6, or may pass through a central orifice therein, as shown in Fig. 7. In Fig. 8, the damping support is shown applied to a radio tube and the like, employing a radially disposed anode and monulating plates, arranged about the central filament 42 In this case, the damping support or rest- 10, is preferably provided with marginal notches, which engage the radially disposed element plates 1a and is further provided with a central orifice through which the filament strand extends. I

Fromthe above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific details shown, but that the means and construction herein disclosed comprises the preferred form of several modes of putting the invention into effect, and the invention is, therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described my invention, I claim:

1. In a thermionic valve, the combinatio with a filament, a grid element surrounding the filament, and a plate element extending on opposite sides of the grid element, of an auxiliary support for the filament with which the filament engages at amidlength point.

said support extending transversely through the grid element and abutting upon the element at opposite sides of the grid element. the filament plane.

' In testimony whereof, I have hereunto set my hand this l9ida' of March A. D. 1926.

2. A thermionic valve, wherein a hairpin type of electrode filament is surrounded by a grid element, and a plate element which extends 011 opposite sides of the grid element,

characterized by a brace of dielectric material interposed between the strands of the hairpin electrode and extending transversely through the grid element into abutment with the plate element on opposite sides thereof.,

3. Means for minimizing microphonic noises of thermionic valves and the like, 1n-

cluding the combination with an electrode filament, an anode and a grid element symmetrically disposed about the plane of said filament of a dampening element engaging the electrode filament of such valve ata midlength point and deflecting the filament in said plane and out of aligned direction to eliminate vibration.

4. In a thermionic valve, the combination with a. hairpin typeof electrode filament having its strands included in a plane, of a spreaded member interposed between and distending the strands but in said same plane whereby microphonio noises due to'filament Vibration is materially reduced. I I

5. Means for supporting a substantially V-type filament of a thermionic valve, comprising a spreader member interposed be-' tween the spaced strands of the filament intermediate its bight and ends, the spreader being of greater extent than the normal spacing of the filament strandsat the points of engagement, whereby the strands are deflected in their normal'plane and out of normal alignment bytheir engagement with the spreader. v

6. The combination with a substantially Y V-sha-ped filament for a thermionic valve, of a spreader interposed between the arms of the V-shaped filament at an intermediate point and deflecting the arms of the filament out of straight lines in contrary directions I but in their normal plane.

7 The combination with a substantially V-shaped filament for a thermionic valve, of a perforated brace member for the filament, through the perforations of which the arms of the V-shaped filament extend, the strandreceiving perforations being diiferently spaced from the normalspacingof the arms at their points of engagement with the brace member, whereby the arms are deflected out of straight lines.

8. In a thermionic tube, the combination with an inverted normally V-shaped filament having its legs lying in a common plane, of an insulating member interposed between the filament legs in straddled fashion and causing them to be outwardly extended but in the same plane, said insulatingmember ly- JO N S. VAN HORNE.

plate ing in a plane substantially perpendicular to CERTIFICATE OF CORRECTION.

Patent No. 1,886,991. November 8, 1932.

JOHN S. VAN HORNE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 26, claim 4, for "spreaded" read "spreader", and iine 27, after "strands"insert the words "out of aligned direction";and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of May, A. D. 1933.

M. J. Moore.

(Seal) Acting Commissioner of Patents.

Images