US 2584653 A
Abstract available in
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Description (OCR text may contain errors)
Feb. 5, 1952 D, ALPERT 2,584,653
WINDOW CONSTRUCTION Filed Nov. 28, 1945 fig. 2.
INVENTOR .Dan/e/ 1940er?.
ATTORNE Patented Feb. 5, 1952 aan;
Lasa-1,65, `Wip oWfoNsfrtUefrio Daniel Alpert, Fiati-Pittsburgh;'j@SSghOI.if Y Westinghouse Electric Corporation, EastPitts- .burgh, Pa., a corporationgf lennsylyania Application November Z, 1 9'4 Serial No. 63l7, 399:` v
. z claims. fici.
f I'Ihis i invention relates to a metal-supported glass window andto the method of vmaking such a window; r Y
. rIn `manufacturing various products, it is often necessary to, provide a vacuum-tight glasswindow acrossan opening in a metal body having a coeiientxof. expansienconsderably higher than that of the glass. In the field of ultra-highnequeny electromagnetic energy,.for example, itis desirablelto have sucha window across an openingin the body of a vcavity resonator, as lshown in my .copendingapplicatiom Serial No. 480,991, filed March 29, 1 943 now Patent Number 2,525,456.- The body-of the cavity resonator, being formed necessarily of a highly conductive `material such' i* asfcopper orbrass, hasa high coefdcient of. ex-v pansion. As illustrated in my copending application, vthe window for Asuch .a body is formed of ayiiat `xnet'allic jplate having an opening4 therein' lled with glassof-substantially the samethickz nessastheplate with a glass-toV-metalaseglgat the edges o f theopening. vThefmetallic plateis formed o f an .alloyhaving substantially the saine coeiiicient of expansion as the glass and is rigidly i secured with a vacuum-tight joint to the body."
, The prior arrangementfjust described `isquite satisfactory under many'conditions even greater efficiency is desired in the'large scale manufacture of windows than is provided by known methods of producing windows'of1- this` type. When high-frequency heating is employed in making the glass-to-metal Aseal in such af window, the glass of the window is invariably. asymmetrialand the sides thereof are not 1sub stantially flat. -Y Such a glass window causesfa diierence inthe amount of electromagnetic energyv-passing throughfdifferent parts of the window, increases the mechanical 4 di'iculties'V in' mounting the window, and renders'the windowl more susceptible to failure under stress, More? glasswindowl.
a new and improvedmetalysupported glass window which may be readily and efciently manufactured inv large quantities.
'fAfurther object of my invention is to provide a'"nove1 metal-supportedglass window adapted to,cbe-rigid1y mounted'on a body having a coefficient of expansion substantially higher. than that-sof the glass. f f
l'sStillanother object of my invention is to providea novel method of forming a metal-supported glass window.
The Afeatures-of my invention which I consider novel areset forth with particularity in the accompanying claims. Theinvention itself, however; together: vwith additional objects and advantages thereof maybe better understood from the following description of a specific embodiment when read Yin'connection with the accompanying drawing, in which:v 1
1. Figure l is a plan view of a metal-supported glass window embodying my invention, as mounted: on a body` having a high coeiiicient of expansion;
-.Fig. 2'is an enlarged cross-sectional lView taken along linel'I--TIy of Fig. 1; and
`:liig.i3 .is a partial view in section of the window of. my inventionY illustrating the position of the glassbeioreand after sealing to the metal support. 1 i-lAs shown in the drawings, a Window is provided for use with a metal body 5 having a high coeiiicient of expansion. By av high Acoefficient of` expansionI mean one greater than that of a suitable'glass so as to preclude a satisfactory glass-to-metal seal between the glass and body for the purposes desired. iThe body 5 has an opening 'l' therein and may also have an annular recess 9 providedabout the opening l on the outer side'of the body in-which recess the window is mounted across the opening.
The'window comprises a relatively thin metaliic'frame 'Il 'having a central opening therein. The plate is formed to have the opening bounded by a surface I3 which inclines away from the center lineof the openingby anv angle of the order of 70 degrees. A at plate-like glass mem ber l5 is mounted across the opening in the frame H and has its edges confor-ming with; and sealedtdthe inclined surface I3. The frame Il is, provided.; with deep annular corrugations be.-
tween its outer periphery and the glass-to-metal seal, the corrugations having a depth up to ten times the thickness of the metal of the frame which is relatively thin so that the frame is exible between the seal and its outer periphery. The frame II is rigidly secured to the body 5 by soldering thereto all around the outer periphery of the frame. With a vacuum-tight glass-tometal seal and with a vacuum-tight joint between the frame II and the body.5, a vacuum may be established on the lower side of the body as in Fig. 2 which would tend to` draw the window down against the/bottom of the recess 9.
The frame II is preferably formed of an alloy comprised essentially of nickel, cobalt and ironr a preferred composition having approximately 23% to 34% nickel, 5% to 25% cobaltwith substantially all of the remainder being iron. With Athis alloy, a borosilicate glass which isnsuitable for sealing with the alloy and having substanf tially the same coefficient of expansion as the alloy is employed. Seals between an alloy com-f prised essentially of nickel, cobalt and iron and a borosilicate glass as may be here employed are described in detail in the Scott Patent No. 2;2"17,42f1-of-Octolier,y 1940;-rv .l
InA manufacturing then'window, a sheet of alloy is first stamped `and punched to form the frame IIA'haying theopening bounded by the inclined surface with the corrugations between the inclined vsurfacerand the outer periphery of the frame'. Then-the frame-is supported withthe Y center line o f the opening therein -substantially Vertical and the inclined surface facing'upvvard. AM substantially flatplate-like glass member is placed on top of the frame acrossthe opening therein as illustrated by the dotted aline member I5'l of Fig. 3; Theiglass member I5A is substantially uniform in thickness with its edges at right angles to the sides thereof, the .glass having the same general configuration but beinglarger'than the opening in the frame whereby the corners formed by theedgesand lower side of the glass member I5 rest on the inclined surface S3 with thelower side abovethe lower extremity of the inclinedrsurface I3 by a vertical distance substantially -no less than one-half vthe thickness of the glass member. Thereafter the frame may be heated by any suitable method, such as by highfrequency heating- As the frame-is heated, the portion of the glass engaging and adjacent to the frame Vbegins to melt and the'glass member slides downward By the time the glass member reaches the horizontal position shown by the solid linemember I5 in Fig. 3, the edges of the glass rncnber. conformwith` and engages the inclined surfacerof theframe as shown. At this time, heatingv offthe' metallic plate is stopped andthe glass-,to-metal seal at the inclined surface is completed. It is to be noted that the angle ofthe incline surface ISof the frame is of importance in determining thel cross-sectional configuration of 'the glass member I5-afterv the seal is made. I have discovered that using-,the alloy and the glass mentioned `with the inclined surface I3 at an angleof-the order of 70 degrees to the verticali, the forceoffgravty, thesurface-tension between the metal and-theglass, and such other factors as may affect the action of the glass, 'combine to enableproduction-of the glassto-metalseal as described with each side of the glass member substantially flat over its entire surface at the compl-etion cfu-the seal. This permits uniform passage-of.electromagnetic-energy through the glass and makes it possible to rlt the window accurately with other machined metal parts. In addition, the area of the glass-to-metal seal is very large with respect to the thickness of the glass member which adds considerably to the strength of the seal and Window.
Along with the added strength of the Window, the provision of a frame which is flexible between the glass and the points at which the frame is secured to the body results in greatly increased protection against failure of the Window under temperature change. By this arrangement, relative movement ofthe body 5 and the glass member l5 caused by temperature changes is absorbed in the flexible frame I I.
It is to be noted particularly that the frame is exiblegradially from the center of the opening therein.
lfinit ttin'g' of the body to other rigid parts of a system, and expansion and contraction of the body radially with-respect to the Window is taken up in the flexible frame. I have found that in such window of the approximate proportions shown in Fig. 2, in which the frame has an outer diameter of the order of inch and the opening therein hasta diameter of the order of inch, the outer diameter of the frame may be changed by as muchas iOlinch without damaging the seal-or glass While I have illustrated the frame as havinga circular outline and with acircular` opening, other shapes may, of course; be used.i
It isf'also to be noted that the frame for the Window may be easilyformed in a punching operation -and the use `of the inclined surface elimin 'ates the need'for any rounding or polishing of theV frame in 'p're'paration for the sealing operation; Moreover, high-frequency heating may be efficiently/used `in making the seal so that the entire window" may be readily and inexpensively manufactured.`
,While I have shown-and described a preferred embodiment of my invention, I am Aaware that many modifications-thereof `may be made Without departing from the spirit of the invention. It is not my intention, therefore, to limit the Vinvention tothe specific arrangement disclosed.
I claim as myfinventi'on':
1. A metal supported glasswindow for use With a' body' cfa` material having a high coeihci-ent'of expansion, comprising a frame of an alloy comprised essentially of nickel, cobalt and iron, said frame having an opening therethrough bounded-on onerside of the frame by a boundary surface inclined away from the center line'of said opening at anV angle of they order of 70 degrees, and-a'- 'glass' plate member extending across said opening substantially perpendicular to said centerline-with the peripheral edges thereof conforming with ,and sealed to KAsaid boundary surface, said glass `member* being of a borosilicate glas's having substantially the same coefficient of expansion as said alloy which is lower than ,.thatfof, said body, said frame being adapted to 5, providing a boundary surface about said opening on one side of the frame which is inclined away from the center line of said opening at an angle of the order of 70 degrees and also providing corrugations surrounding said boundary surface whereby said frame isflexible in the region of said corrugations, and a borosilicate glass plate extending across said opening perpendicular to said center line with the peripheral edges thereof conforming With'and sealed to said boundary surface, said glass having substantially the same coeicient of expansion as said alloy.
REFERENCES CITED The following references are of record in the le of this patent:
UNITED STATES PATENTS Number Name Date 1,614,156 Schmidt Jan. 11, 1927 2,050,576 Kronquest Aug. 11, 1936 2,075,477 Smith Mar. 30, 1937 2,219,573 Fraenckel Oct. 29, 1940 2,259,751 Kelley, Jr Oct. 21, 1941 2,296,307 Power Sept. 22, 1942 2,318,435 Stupakoi et al. May 4, 1943 2,419,049 Alpert Apr. 15, 1947