US3202494A

US3202494A - Method and apparatus for producing multiple sheet glazing units

Info

Publication number: US3202494A
Application number: US21682A
Authority: US
Inventors: John A Woods; Co Ohio Citizens Trust; Alfred E Badger
Original assignee: Libbey Owens Ford Glass Co
Current assignee: Libbey Owens Ford Glass Co
Priority date: 1960-04-12
Filing date: 1960-04-12
Publication date: 1965-08-24
Anticipated expiration: 1982-08-24

Description

Aug. 24, 1965 J. A. woons ETAL.

METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS 7 Sheets-Sheet 1 Original Filed July 25, 1962 a 3nneutor$ WM a y We Aug. 24, 1965 J. A. WOODS ETAL 3,202,494

METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS Original Filed July 25, 1962 7 Sheets-Sheet 2 I 1 14;.4 my 5 as i d Fnventorfi Aug. 24, 1965 J. WOODS ETAL METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS '7 Sheets-Sheet 3 Original Filed July 25, 1962 Aug. 24, 1965 J. A. woonns ETAL 3,202,494

METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS za flefvdgzl -e ma m FM on GT 0? Original Filed July 25, 1962 Gtiomegic Aug. 24, 1965 J. A. WOODS ETAL METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS Driginal Filed July 25, 1962 7 Sheets-Sheet 6 Ihwcnters (maid 0% v6 m @m 7 Sheets-Sheet 7 w uwwm M M n 1 4. 11 w 5 m 1 w 6 5 3 z a if. wam/ 7 1/ 1 & @W

3% m a M f K m L 1.. M N 2 M F n w 1 fi 7v 1 5 a anal Wigs

Aug. 24, 1965 J. A. WOODS ETAL METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS Original Filed July 25, 1962 United States Patent Ofice EidZAdd iatented Aug. 2%, 1%55 El A 3,2il2, -'--4- MEIHUD AND FQR PRQBUEENL} UNETS John A. Woods, Lancaster, @hio, Donaid E. Sharp, de-

ceased, late oi v aumce, @hic, by @hio Citizens Trust Co., executor, Toledo, (Erie, and if-red E. Badger, lvlaumee, fihio, assiguors to Libbey-@wcns-Ford Glass Company, Toiedo, @hio, a. corporation of @hio (Tontinuation of application Ser. No. 567,135, Felt. 23, 1955, which is a continuation of application Ser. No. 309,834, Juiy25, 1352. This application Apr. 12, N69, Ser. No. 21,632

3 Claims. ((31. 6558) The present application is a continuation of application Serial No. 567,185, filed February 23, 1956, now abandoned, which is a continuation of application Serial No. 300,884, filed July 25, 1952, now abandoned.

This invention relates broadly to all-glass multiple sheet glazing units. In particular, it relates to an apparatus and method for sealing together the marginal edge portions of spaced sheets of glass to produce a hermetically sealed glazing unit, the sides of which are formed by the union of said marginal edge portions.

Multiple sheet glazing units may be described generally as comprising two or more sheets or" glass which are sealed entirely around their marginal edge portions in spaced relation to provide a hermetically sealed dead air space therebetwecn. Due principally to their insulating and condensation preventing qualities, such units have become well established fixtures in the building trades and have found wide usage as windows for buildings, show cases, vehicles, refrigerators, and the like.

in the early development of the multiple sheet glazing art, it was customary to seal together the marginal edge portions of the spaced sheets of glass by means of strips of a substantially impervious material which were placed between said portions and bonded thereto in any suitable manner. In many cases, the seal so produced was found not to be hermetic and the unit thus impractical for the purposes of improved insulation and the prevention of condensation. As Well, in other instances, the sealing process was found to be so cumbersome and expensive that production on a mass basis was practically impossible.

it has been found in accordance with this invention, that a hermetically sealed glazing unit can be formed entirely of glass by means of a method which is relatively simple, inexpensive, and well-suited to mass production techniques.

It is therefore an object of this invention to provide a hermetically sealed, all-glass multiple sheet glazing unit and in particular to provide a relatively simple and inexpensive method of forming such units.

Another object of this invention is to provide a novel method for sealing together the marginal edge portions of spaced sheets of glass to form a hermetically sealed space therebetween.

Another object of this invention is to provide a method of producing multiple sheet glazing units in which the marginal edge portions of spaced sheets of glass are heated to the bending temperature thereof and fused in ealing relation with one another.

Still another object is to provide a novel apparatus for producing all-glass multiple sheet glazing units in accordance with the method of this invention.

Still another object is to provide an apparatus for producing multiple sheet glazing units comprising a furnace, a heat source in the furnace, means for supporting sheets of glass in fixed spaced face-to-face relation, and means for moving said supporting means and heat source relative to and past one another to progressively seal the edge portions of the sheets together.

Briefly stated, this invention contemplates the production of hermetically sealed glazing units made entirely of glass by means of a method and apparatus in which two or more sheets of glass are supported in fixed spaced facc-to-face relation and moved past concentrated heat sources to cause the marginal edge portions thereof to unite and thereby seal off a dead air space between said sheets. Thus, according to the invention, concentrated heat sources may be directed to first one and then the other pair of opposite marginal edge portions of the glass sheets, as they are supported in fixed spaced relation and moved therepast, to cause said edge portions to become molten and unite with one anothen Or, it preferred, the marginal edges of the glass sheets can be sequentially sealed by subecting first one edge and then another edge to the action of the heating means.

In the accompanying drawings, wherein like numerals are employed to designate like parts throughout the same:

FIG. 1 is a perspective view or" an all-glass multiple sheet glazing unit produced in accordance with this invention;

FIG. 2 is a perspective sectional View of one corner of the glazing unit taken substantially along line 22 of FIG. 1;

FIG. 3 is an over-all perspective view of an apparatus for producing the glazing unit and showing the furnace, conveyor, and burners;

FIG. 4- is a fragmentary sectional view of marginal edge portions of one side of spaced sheets of glass prior to being subjected to a concentrated heat source;

F365. 5 to 7 are fragmentary sectional views of said edge portions as the heat source is applied thereto and they are caused to soften and bend into contacting relation With one another;

FIG. 8 is a fragmentary sectional view of said edge portions after they have been fused under the influence of said heat source to hermetically seal the side of the glazing unit;

FIG. 9 is a representation of a photograph of a cross section of a typical seal for a side of a glazing unit produced in accordance with this invention and showing by illumination and magnification the flow lines of the fused portions of said side;

PEG. 10 is a fragmentary perspective view of a tray with the spaced glass sheets supported thereon;

FIG. 11 is an enlarged plan View of one of the supporting arms of the tray in supporting position;

FIG. 12 is a sectional view of the supporting arm taken substantially along line lit-d2 of MG. 11;

FIG. 13 is a longitudinal sectional view of the furnace, taken substantially along line 13-ll3 of FIG. 3, and showing the tray prior to its movement past one of the burners;

FIG. 14 is a transverse sectional view of the furnace, taken substantially along line l4-14 of FIG. 13, with the tray removed;

FIG. 15 is a detailed perspective view of an adjusting device for a knock-out pin adapted to engage the tray supporting arms and move the same to a non-supporting position;

FIG. 16 is an enlarged transverse sectional view of a portion of the furnace and one of the burners, similar to FIG. 14 but showing the tray in operative relation with one of the burner heads;

FIG. 17 is an enlarged detailed sectional view of one of the pivotable hinge connections for the burner head of FIG. 16;

FIG. 18 is a plan view of one of the burners and a portion of the furnace shown in FIG. 16;

A and B are burners 37.

sealed unit. 7

7 FIG. 19 is a transverse sectional view of the burner of i FIG. 18 taken substantially along the line 19-ll9;

FIG. 20 is a plan view of a limiting device for the burner of FIG. 18, taken substantially along line 29- 2%) of FIG. 19;

FIG. 21 is a frontyiew of one of the burner heads;

FIG. 22 is a longitudinal sectional view of the burner head, taken substantially along line 2222 of FIG. 21, and the gas inlet and coolant inlet and outlet thereto;

FIG. 23 is an enlarged transverse sectional view of the burner head, taken substantially along line 2323 of FIG. 22; I

' FIG. 24' is a transverse sectional view of the burner head, taken substantially along line 24-24 of FIG. 22; 7 FIG. 25 is a transverse sectional view of the burner head, taken substantially along line 25-25 of FIG. 22;

FIG. 26 is a transverse sectional view of the burner FIG. 27 is a sectional View, taken substantially along line 27--27 of FIG. 22 and showing the gas'inlet and coolant inlet and outlet of the burner head.

Referring now to the drawings, there is shown in FIG. 3 a perspective view of an apparatus 30 by means of which an all-glass, multiple sheet glazing unit 31 may be produced in a manner to be hereinafter described. This apparatus includes a generally U shaped, horizontally movable conveyor 32, over which are mounted, in order of use, a preheating compartment 33 and a furnace 34, conforming in shape generally to said conveyor. the furnace there are arranged, between the entrance 35 and exit 36 thereof, a first sealing area A, a second sealing :area B, and an annealing area C. Disposed outwardly of the furnace at opposite sides of sealing areas The all-glass, multiple sheet glazing unit 31, produced in accordance with this invention, comprises upper and lower sheets of

glass

33 and 39, respectively, and side portions 40 between the marginal edge portions of said sheets, forming therebetween an enclosed space 41 Disposed toward an ,edge or corner of onesheet of the unit is a dehydration hole 4-2,. (FIG. 1) which may be hermetically sealed toseal oil the enclosed space 41. v

' More particularly, the side portions 4% of the unit are composed of an innerwall 43 substantially perpendicular to'upper and

lower sheets

38 and 39 and an outer wall 44 angularly disposed thereto to form an enlarged base portion 45 adjacent the marginal edge portions of said lower sheet. rectangular in cross section and the outer periphery of the unit substantially trapezoidal. The corners. of enclosed space 41 at the intersection of inner wall 43 and

sheets

38 and 39 arerounded or filleted, as best shown in FIG. 9. a

As previously mentioned and in a mannento be more fully described hereinafter, the all-glass unit 31 is pro duced by assembling the upper and lower sheets38 and 39in fixed spaced relation, as shown in FIG. 4, properly preheating the sheets, and moving them-past concentrated heat sources from burners 37 to cause the marginal edge portions thereof to progressively soften, as shown in FIG.

5,'unite, asshown in FIGS. 6 and 7, and ultimatelybecome. sealed to one another, as in FIG. 8. t

As assembled and prior to being sealed,.upper sheet 38 is relatively larger than lowersheet 39 such that a peripheral portion of said upper sheet extends outwardly ,7 beyond the marginal edge of the lower sheet. It is also cumulation of the marginal edges of said upper sheet at of each'corner of the the enlarged base portions 45 'When the spacedsheets'are moved therepast, the concentrat ed heat sources are directed toward the marginal edge portions of opposite sides of the spaced sheets in lower sheet '39 and those of the lower sheet to curl up- Thus, enclosed space 41 is substantially Within 30' wardly a slight amount (FIG. 5). Toward the completion of the passage of the sheets past the heat sources,

such that the edges thereof will unite with the edge per-- tions of the lower sheet adjacent said lower sheet (FIG. 6). Further heating will cause the united marginal edge portions to become more molten and the line of fusion between the same to increase, as shown in FIG. 7. At the completion of the passage of the sheets past the heat sources, the marginal edge portions of the opposite sides of the sheets will be firmly united and fused to one another at the broad base portion 45 (FIG. 3) to form a seal therebetween.

This'seal has been foundto be exceptionally strong and permanent rather than a source of weakness in the unit. To illustrate the manner in which the marginal edge portions are finally united, a photograph was taken of a magnified cross section of a typical seal produced in accordance with this invention and which had been illuminated frointhe rear, and is'represented in the drawings by FIG. 9'. As can be seen therefrom, the flow of the layers of molten glass is such that there is a relatively wide line of contact 47 at the. unionof the marginal edges of upper and

lower sheets

38 and 39, thus adding to the strength of the lower corner of the unit. Further, it can be seen from FIG. 2 that, due partly to the removal of the corner portions 46 of upper sheet 38, the corners of the sealed unit are rounded and do not present protuberances which might later require removal in the assembly of the unit in a suitable sash.

1 In being moved past concentrated heat source to effect the seal described above, upper and

lower sheets

38 and 39 are supported in properly spaced relation on a tray 48, which is moved on conveyor 32 forwardly through furnace 34 and past burners 37 in a manner to be described hereinafter. .An elevational view of the entire tray 43 is shown in FIG. 13 and an enlarged but fragmentary view of the same can be seen in FIG. 16. However, particular reference is had to FlGS. 10 to 12 for a description of the novel construction of the tray and its respective parts.

In plan, the tray 43 corresponds substantially to the outline of the glass sheets supported thereby.' For purposes of illustration, the sheets and tray are shown as beported on the upper edge of said rim. Additional support may be provided for the suspended central portion of said lower sheet by a rib 53 (FlG. 16) extending between opposite sides of upper rim 5t and having a rounded upper edge in horizontal alignment with the upper edges of said rim.

A p'a n fie of sheet rnetal or other suitable material is secured at each of its edges to struts 51 and braces 52 intermediate upper and lower rims 5t and 49. in this manner, in the case of breakage of the glass sheets, the particlesthereof are prevented from falling into the conveyor mechanism or onto the bottom of the furnace. As well, pan 54 servesto shield thebottom of lower sheet 39 from the heat of the furnace to prevent bending or bowing'of the suspended central portions thereof. Prior to the plac- 7 ing oflowersheet 39 on the upper rim of the tray, the

'lfiissubstantiallytrapezoidalin a transverse cross section. Adjacent the upper rim of the tray and secured betweenthe apices of adjacent struts 51. are a plurality of bearings 55 having vertically bored journal openings 56. Pivotally mounted within each of the openings are pins 57 having headed portions 58 upon which are carried upper sheet supporting arms 59.

The arms 59 are slidably received in a channel through the upper side of said headed portions 58 and each of said arms is attached thereto by a bolt 6?) extending through a slot 61 in said arm and threadedly received in said headed portion. Thus, upon loosening bolt 6d, arm 59 may be moved a limited distance in a defined path through the channel of headed portion 58. Of course, upon tightening its respective bolt, each of the arms 59 may be securely locked in place in the desired position.

Each of said arms is indented at its inner end to form a ledge 52 for supporting the marginal edge portions of upper sheet 38 in proper spaced relation to those of lower sheet 39. Handles 63 extend outwardly from the opposite ends of the headed portions of each of the pins 57. Thus, each of the arms may be selectively swung by handles 63 in the plane of sheets 33 and 3d from an upper sheet supporting position, as shown by the three leftmost arms in FIG. 10, to a non-supporting or knocked-out position, as shown by the rightmost arm in said figure.

Preparatory to mounting upper sheet above lower sheet 39, each of the arms 59 is swung to the supporting position and, if necessary, is adjusted in a direction perpendicular to the edge of the upper sheet to be supported thereon such that said sheet will be supported by each of the ledges 62 in at least substantially vertically aligned relation with respect to the lower sheet. When both upper and

lower sheets

38 and 39 have been properly assembled on tray 43, in the manner described, the tray may be placed upon conveyor 32 so as to be moved through the preheating compartment 33 and furnace 34 and past concentrated heat sources in th form of burner heads on burners 3'7, as indicated by the broken lines of FIG. 12. To prevent bending or bowing of marginally supported upper sheet 3% during its passage through the furnace, strips of glass cloth (not shown) may be placed over the top thereof to shade all but its marginal edge portions from the concentrated heat sources.

Preheating compartment 33 is supported above conveyor 32 in slightly spaced relation thereto and is provided with suitable interior heating elements (not shown) by means of which

sheets

38 and 39 may be preheated, prior to their entry into furnace 34, for a purpose well known in the art. Doors 64 are provided at one side of the compartment for placing the tray and sheets on the conveyor inside the chamber. An exit (not shown) at the side of the compartment facing the entrance of the furnace permits the tray 48 resting on conveyor 32 to be moved forwardly from the compartment to said furnace entrance. Alternatively, of course,

sheets

38 and 39 may be properly preheated within the forward end of the furnace, in which case merely changes in temperature control within the furnace would be required.

Conveyor 32 is composed of a series of spaced, horizontally disposed rollers 6% supported at each end on horizontally disposed channels 66 (FIG. 16) secured to the upper ends of uprights 67 which are spaced at intervals parallel to and at each side of furnace 34. Channels 68 are secured to and extend between said uprights for supporting the bottom of said furnace at an elevation intermediate the rollers and floor level. Enlarged feet 69 may be provided for the lower ends of uprights 67 as shown in FIG. 13.

Rollers 65 are preferably hollow cylinders formed of any suitable material and spaced apart along the length of the furnace a distance sufficient to provide adequate support for the length of tray 4% (FIG. 13). The ends of the rollers extend through openings 76 in each side of the furnace and are provided with outwardly projecting spindles 71 which are journale-d in bearin s 2 mounted on channels 66. Secured to one outer end of each of said spindles is a sprocket wheel F3 adapted to actively engage with the upper run of link chain 74. As best shown in FIG. 16, the upper run of the chain is supported on a longitudinally extending channel member 75 and the lowor run thereof on a similar member 76, both of which are secured to uprights 6! outwardly thereof. A guard '77 is secured to members 75 and 7 6 and may be provided with an upper flange portion 73 for protecting sprocket wheels 73 as well as link chain '74.

Thus, by any suitable power means (not shown) link chain may be moved forward in the direction of the movement of tray 43 through furnace 34 to cause rollers 65 to rotate in a corresponding direction for so moving said tray. It is to be understood, of course, that a similar mechanism may be provided for each straight section of the conveyor 32, in the first and second sealing areas A and B and annealing area C of the furnace. By means of a directional transfer mechanism (not shown) and by coordinating the operation of the driving mechanisms for each conveyor section, a continuous movement may be provided through furnace 34% from the entrance 35 to the exit 36 thereof.

Furnace 34 i of a generally U shape conforming to conveyor 32, as previously mentioned, and is composed of top and bottom walls 7d and dd, respectively, and side walls 81 of any suitable refractory material. Bottom wall be is supported by the channels 63 at a level spaced from and below the rollers 65 of conveyor 32, and top wall 79 is elevated above said rollers a distance sufficient to permit the free movement of tray 48 through the furnace as well as the movement of the forward portions of burners 37 through openings 32 in the side walls 81. Shields 83 (FIG. 18) may be provided at the outer side of side walls 31 of the furnace for covering the open spaces in openings 82 around burners 37. Gpenings S4 in said shields permit the passage of rollers 65 therethrough.

As well, Selas type heating elements 85 may be provided in each side wall of the furnace above and below the path of tray 48 (FIGS. 13 and 14) at a number of locations along the length of said furnace for maintaining the respective locations at the desired temperature. Fuel gas for the heating elements 35 may be provided from any suitable source (not shown) to a conduit as (FIG. 14) above the furnace and supplied to said heating elements at each side of the furnace by branch pipes 37. The temperature of each area of the furnace may be controlled by any suitable means, such a valves 88 on the branch pipes and proper heat distribution obtained by means of the areas of the furnace above and below rollers 65.

Each of the burners 37 includes a burner head 89 and means for mounting same in proper elevation with respect to upper and

lower sheets

33 and 39 on tray 43 when moved therepast, a knock-out pin 98 for engaging handles 63 of the upper sheet supporting arms 5? of the tray, in a manner and for a purpose to be described, rails $1 adjacent opening 82. and disposed perpendicular to and outwardly from the side walls 81 of the furnace over which the burner head mounting means may be moved inwardly and outwardly of opening 82 and into operative position with respect to the marginal edges of the glass sheets, and aligning rollers 92 for properly orienting the tray and burner head with respect to one another during movement of the tray therepast.

Rails 91, upon which the burner head mounting means is supported and adapted to be guidably moved, are secured by any suitable means, such as bolts 93, to horizontally extending channels 94 which, in turn, are supported from upright angle irons d5 to form a substantially rectangular table constructed independently of the fur trace. The lower ends of the uprights 95 may be provided with feet $6 and cross member 97 (FEG. 16) may be extended between the webs of channels 94 to add rigidity to the table structure. As well, cross members 93 and aeoaasa 99 may be extended between the lower ends of the uprights.

The mounting means for each of burner heads 87 is provided with a base plate 1% having notched portions 181 at each side thereof for slidable engagement with the upper inner edges of rails 91. A series of lower cross bars 1112 may be releasably held in engagement with the opposite lower edges of the rails by means of bolt 1113 (FIG. 19). Thus, the cross bars 162, in addition to maintaining the burner head and mounting means therefor on rails 5 1, permits the base plate 111% to be either locked in place or to be moved in frictional engagement over rails 11 into the desired position relative to the furnace.

It is, of course, necessary in practicing this inventionthat the marginal edge portions of the glass sheets 38 and 39m be sealed be moved past the burner heads 89 at each side thereof in perfectly aligned relation.- That is, both the upper and lower rows of-nozzles 1M and 165, respectively, on the burner heads must be in parallel relation to and equally spaced from said marginal edge portions at both sides of the furnace at all time during the passage of the sheets therepast. For this purpose, there is provided, in accordance with thisinvention, an arrangernent whereby the forwardly moving tray 48 will be caused to coact with rollers 92 of the opposed burners 37 to automatically dispose the nozzle rows 164 and 19:5 in properlyaligned relation with respect to the marginal edge portions of the glass sheets.

To be more specific, burner heads 89 on each of the opposedburners are mounted above base plates 1% in such a manner asto be normally resiliently urged inwardly toward one another. in addition, the mounting means for the burner'heads are pivotally connected to said base plates so as to be movable outwardly with respect thereto. Thus, when base plates 1% are locked in place on rails 91, burner heads $9 of opposed burners may be caused to move outwardly from one another, and relative to said base plates, from their normal inwardly urged position.

Thus, in practicing this invention, burners 37 may be moved into a position in which the rollers 92 suspended from housings 1% secured to the burner heads 89, will be spaced apart transversely of the furnace a distance just less than the length of the sides of lower rim 49 of tray 48. Inthis manner, when the tray is moved forwardly in at least approximatelyaligned relation with the space between opposed rollers, the opposed sides of said rim will coact with the rollers for the opposed burner heads 89, in moving therepast, to cause said burner heads to move outwardly an amount just sufiicient to permit the opposite sides of the lower rim of tray 48 to pass through the rollers 92 frictionally engaged thereby. To put it another way, the opposed burner heads will be spread out by tray 48 from their normal position to what may be called an operative or sealing position 7 1 Of course, when'tray 48 is so disposed between the rollers 92 and the marginal edge portions of the glass sheets are actually being fused the burner heads 89 are maintained'in the'operative position by the inwardly urged mounting means therefor. That is, the arrangement of saidmounting means above the base plate 1% serves, when saidbase plate is rigidly locked in place, to contoward the forward (uppermost in FIG. 18) end of the furnace, is relatively shorter than sleeve 108 and is'pivotally mounted at its outwardly disposed end above base plate 1% by a hinge connection 110. The longer sleeve 1118, on the other hand, is pivotally mounted above said base plate by two similar connections 110, one of which is locatedat its outwardly disposed end and the other at a point inwardly of the connection for sleeve 107.

One of the hinge connections 109 is shown in detail in FIG. 17 and comprises arms 111 secured to the rear wall of housing 106 and having threaded vertical openings 112. Suitably bored openings in a connecting arm 113 are journaled on opposed hinge pins 114, received in 1 a hub portion extending upwardly therethrough, over which a'journal opening in one end of said arm is adapted to pivot. The opposite end of swinging arm 116 is suitably bored to receive the hub portion of a similar pin 118 which extends downwardly through a bearing sleeve 119 received in openings through either of the sleeves 107 As can'be seen from FIG. 18, the tubular columns 115 and axes of binge pins 117 for each of the connections 111 are disposed in substantial alignment along the longitudinal axis of base plate 190. Thus, in the operative or sealing position of the burner (as shown in said figure), sleeves 107 and 1418 are in substantially parallel relation. As well, it will be understood that in swinging on the two hinge connections 11%, sleeve 108 will traverse paths which are at all times parallel to one another. On the other hand, it is equally 'apparentthatsleeve 107, swinging on only. .the single hinge connection 110, will move in paths the directions of which relative to one another will be dependent on the movement of burner heads 89. Thus, there is provided, in a manner to be more fully explained hereinafter, an arrangement for mounting the burner heads which will automatically give and subsequently right itself as the burner 37 is contacted by and aligned with a side of tray 48.

stantly maintain the rollers 92 for each of the burner heads in frictional engagement with the opposed sides of rim 49.. it will'be understood, therefore, that when said tray is disposed between all four rollers, two on each side, the rows of nozzles on the burner headswill auto,-

matically be properly aligned with respectto the opposed marginal edge portions of the glass sheets 33 and39.

Dealing now specifically with the arrangement of the mounting means for each of said burner heads, mounting sleeves 1117 and 1118 are attached at their inwardly disposed-ends to the rear wall of the housing- 1% by means of pivotal hinge connections 109. Sleeve 107, disposed As a means for normally urging the mounting means for opposite burner heads inwardly toward one another, tension springs 120 (shown in detail in FIG. 20) are extended between swinging arms 11s on the hinge connection 11s for sleeve 107 and a portion of base plate as well as between swinging arm 116 on the rear connection 11%) for sleeve 168 and another portion of said base plate. In both instances, however, the portion of base plate 190, to which one end of spring 126 is attached, is forwardly of the arm to which the other end of the spring is attached. Thus, tension springs 120 provide resilient means for normally urging each of the sleeves inwardly.

Dealing now specifically with one of said tension springs, bracket 121, securely mounted on base plate 16.0, includes at oneend thereof an upstanding arm 122 having an op ning through which apin 123;may be threaded. The tension spring 120 is hooked at one end through an eye on said pin and at thc'other end to a small plate-124 secured to swinging arm 116. The tension in said spring may be adjusted by the manipulation of pin 123 and lock nuts 125. At the opposite end of bracket 121, upstanding arm 126 receives, through a threaded opening therein, a limit screw 127 which is disposed in alignment with the side edge of'arm 116. By means 'of lock nut 128, the end of said screw may be adjustably positioned, as desire-d, to limit the positiont-o which; swinging arm may be urged in i wardly by tension spring 120. r

i Asshown in FIGS. 18 and 20, for example, the burner head mounting means is in the operative position in which the swinging arms 11s for each of the hinge connections 110 are disposed parallel to one another and perpendicu ar to the parallel sleeves 1&7 and 108. In this position, each of the arms 116 is urged outwardly against the tension in springs 12% and is spaced slightly from the end of limit screws 127. On the other hand, in the normal inwardly disposed position of burner heads 89, the adjacent side edges of arms 116 will be in abutting relation with said limit screws such that each of the arms is disposed at least generally obliquely to sleeves 167 and 1%. Thus, it will be understood that the front face of burner heads 89, and the rows of nozzles 16 i and 1% will be moved from one position parallel to the movement of conveyor 32 and tray 48 supported thereon to another position spaced from but parallel to said first-mentioned position.

Of course, in the normal position, none of the rollers 92 have been contacted by lower rim 49 of tray 48. In the operative position, however, the tray is disposed between all four rollers. Intermediate these positions, only the forward rollers, one on each opposite burner, is engaged by the forward end of the tray. Thus, as the forward end of the tray moves into the engaging position with the for- Ward rollers, the burner head mounting means Will be caused to undergo the give aforementioned.

Specifically, on each burner head 89 the forward rollers will be moved outwardly causing sleeve 197 to swing on its hinge connection 109. As a result, arm 116 of sleeve 197 will swing in the opposite direction on hinge pin 117 away from its limit screw 12.7 and assume a position at least approximately perpendicular to the longitudinal axis of base plate 1%. As the tray 48 moves further past burner heads 89, its forward end will engage the rear rollers 92 as the forward rollers are maintained in their outwardly disposed position. In compensating for the movement of the rear rollers, each sleeve 168 will be swung on its hinge connection 189 and arms 116 for each of said sleeves will be swung in the opposite direction to assume positions at least approximately parallel to the 116 for sleeve 137. Of course, as tray 48 travels still further, lower rim 49 will move out of engaging position with forward rollers 92 and the arm 116 for each sleeve 107 will return to its position in abutting relation with limit screw 127. When the tray is moved its entire length past the rollers, the arms 116 for each sleeve 1th; will assume similar positions, at which time the burners will have returned to their normal inwardly disposed position.

As previously mentioned, it is necessary that the rows of nozzles lilo and 195 on opposed burner heads 89 be disposed in perfectly aligned relation to the opposite edge portions of the

sheets

38 and 39 during the actual sealing of said edges. That is, it is an important feature of this invention that the flames from the nozzles be directed t the edges of the sheets in a predetermined and constantly maintained relation during the actual sealing thereof.

Therefore, to provide the proper coordination between the aligning of the opposite edges of the glass sheets with the burner heads '39 and the actual sealing of said edges, the tray 48 is specially constructed, in a manner previously described. That is, the cross section of the tray as is substantially trapezoidal with lower rim 49 thereof pro- ,iecting .a substantial distance outwardly beyond upper rim As will be more fully understood from FIG. 13, the amount of this projection is slightly greater than the longitudinal distance between rollers 92 on each burner head. In this manner, prior to the passage of any portion of the opposite side edges of the

sheets

33 and 39 past the nozzles of the burner heads 89, those portions of lower rim 49 projecting beyond upper rim 50 will have moved said burner heads to the operative or sealing position. 'In like manner, the burner heads 59 will be maintained in the operative position by the similar projecting portions of lower rim 49 at the rear end of the tray until the entire lengths of the opposite edges have been sealed.

The actual sealing of the marginal edge portions of upper and

lower sheets

38 and 39 is performed progressively along opposed sides of said sheets. That is, as they are passed by the burner heads 89, the marginal edge po tions of the sheets are almost instantaneously fused toe gether as the flames from the rows of

nozzles

104 and 195 are played therealong. That is, each portion of said opposed edges is moved past the entire length of the upper and lower rows of burner head nozzles and, after having so passed, each of said portions is almost instantaneously fused as its spaced marginal edge portions are rendered molten and caused to unite in a manner previously described.

Upper sheet supporting arms 59 have also been previously described as being movable from a supporting to a non-supporting or knocked-out position. For the purpose of progressively engaging the handles 63 of the arms on opposed sides of the tray 4S, as it is moved therepast, knock'out pins 96 are so supported from each of the opposite burners at the forward sides thereof as to engage said handles just prior to the movement of those portions of the glass sheet marginal edge portions supported thereby past the burner heads 559. That is, with particular reference to FIG. 13, it can be seen that as tray 48 moves past knock-out" pins prior to moving past the burner head nozzles, each of the upper sheet supporting arm handles 63 will be progressively moved to the knocked-out position.

In this manner, the opposed marginal edge portions of the sheets being fused will at all times during the fusing thereof be supported in properly spaced relation. That is, for example, as the supporting arms 59 for the forward end of the upper sheet are removed from their supporting position and said forward end of the upper sheet is in the process of being fused with that of the lower, the remaining lengths of the opposed edges are maintained in properly spaced relation by the remaining arms 5d. As well, due to the fact that the fusion takes place almost instantaneously, those portions of the opposite marginal edges, which have passed burner heads 39 and have been transformed into side portions 40, also provide supports for properly spacing the sheet. Thus, by a combination of said fused portions of the sheets as well as supporting arms 59, upper and

lower sheets

38 and 39 are at all times during the sealing operation maintained in properly spaced relation.

Knock-out pin t depends from a rod 129 which extends substantially parallel to sleeve N7 and is slidably received in a bearing sleeve 130 (FIG. 15). Set screws 131 are received through the top of the sleeve for locking rod 129 in place when it has been moved to the desired position longitudinally of the burner head mounting means. Threaded pins 132 depend from sleeve 13%) and are received in slots 133 in the upper plate 13 of an 1 shaped support member 135. Lock nuts 136 serve to support the sleeve on said pins 132, in fixed relation above upper plate 134. The lock nuts may be loosened to permit pins 132 to be moved in slots 133 vertically as well as transversely of the burner head mounting means. The lower plate of support member 135 may be secured to rail '91 in anysuitable manner.

By means then of the particular apparatus described in connection with FIG. 15, the knock-out pin 9i may be moved into any desired-position to engage handles 63 of the upper sheet supporting arms 59 at a point along the path of said tray which Will permit ledges 62 of said arms to be entirely removed from between

glass sheets

38 and 39 prior to the movement of those portions of upper sheet 38 supported by said ledges past the burner heads 89. Thus, as shown in FIG. 13, the pin 93 is spaced slightly forward of burner head 89 such that just after a ledge 62 is entirely removed from a portion of the marginal edges of the glass sheets, flames from the rows of nozzles 104 and N5 will be directed thereto.

Although best results have been obtained by the particular arrangement of the burner head nozzles with relation to the marginal edge portions of the glass sheets disclosed and described herein, it is to be understood that this invention is not restricted thereto. Generally, however, it-may be said that the nozzles on the burner heads should be arranged close enough to said marginal edge portions that the flames therefrom will be actually played along said portions of both sheets, such that they will be caused to become molten and bend or curl in substantially. thernanner previously described.

It has been found that in actual practice, with glass sheets of approximately /s"'thicknessand-spaced apart approximately A", a permanent seal may be obtained by arranging the burner head nozzles with relation to said sheets in the manner shown in FIG. 12. As shown therein, the nozzles of the upper row 104 are spaced about As" above upper sheet 38 and are directed perpendicularly thereto in substantial alignment with the edge of lower sheet 39. The nozzles of the lower row 1% are spaced a similar distance above the edge of lower'sheet 39 and are disposed at an angle of about 45 degrees to the plane thereof. 7

Thus, as the sheets are moved past the burner heads, the flames from the upper row 164 of nozzles will cause the marginal edge portions of the upper sheet to become molten and bend toward those of the lower sheet. Simultaneously, the flames from the lower row 1W5 of nozzles will cause a relatively smaller part of the marginal edge portions of the lower sheet 39 to curl upwardly. When said marginal edge portions have united and reached approximately the position shown in F16. 6, theflames from the upper row of nozzles will further cause the united portions to become more molten and the line of fusion '47 to increase, as previously described with respect to FIG. 7. At the very final stages of the fusing, the flames from the lower row of nozzles will be played along said line of fusion to perfect the seal between the side of the sheets.

The sealed molten marginal edge portions of the' Of course, a device of this kind may take any number of forms in which, for example, the forward end of the tray 48 is caused to actuate automatic means for transferring said trayfrom one section of conveyor 32 to another. At any rate, the particular mechanism for so indexing tray 48 does not forma part of this invention and is not illustrated herein. For that matter, rather than being constructed in the substantial U. shape shown, if space permits, furnace. 34- and conveyor 32 maybe constructed in either an L shape or a straight line.

Regardless of the particular shape of the furnace and conveyor, however, tray 48 is moved continuously through the furnace in a manner to expose firstone and then the other pair of opposite edge portions of glass sheets 38 and'39 to the flames from the opposed burners 37. 'Although the tray 48 has been shown herein as substantially I square, it will be understood that the positionof the sheets may be set and the suspended inner portions prevented from sagging by a jet of air directed along the lengths thereof to rapidly cool the same shortly after theyhave passed the burner head 89. Air for this purpose may be supplied from any suitable source (not shown) and carried through a pipe 137 (FIG. 18) extending along the rear side of the burner head mounting means to a nozzle 133 having a vertically directed opening disposed above the path of the marginal edge portions of the glass sheets. The pi e 137 maybe supported along its length from a bracket 139 upstanding from rail 91 and a mounting sleeve 14% secured to and spaced from therear side of burner head 89.

Additional aligning rollers 141 are suspended from supports-142 secured to the side walls 81 of the furnace at each side thereof forwardly of eachof the sealing areas A and B and in substantial alginment with the space between the normally urged rollers 92 on burners 37. The rollers 142 may be spaced apart a distance slightly greater than the Width of the lower rim of tray 48 for properly aligning the sameprior to its movement into engaging relation with rollers 92. If desired, the rollers 141 may be suspended-from supports 142 in inwardly converging relation.

It'will also be understood that in sealing

glass sheets

38 and 39 entirely around the marginal edges thereof,

7 rear wall of housing 106.

burners may be adjusted to accommodate trays of most any rectangular shape.

Intense localized heating for sealing the marginal edge portions of the glass sheets is supplied by flames from an oxygen and natural gas mixture. For this purpose, the oxygen and gas for each 0f the burner heads 89 are supplied from a suitable source (not shown) through

pipes

143 and 144, respectively, to a mixing chamber 145. From the mixing chamber 145, aconduit 146 extends 7 toward. burner head 89 and carries theoxygen-fuel mixture to a flexible hose 147 which in turn is connected to one end of an oxygen-fuel inlet pipe 148.- The inlet pipe 148 extends through the entire length of aconcentrically arranged conduit 150 and is threadedly received at its other end in the rear wall of the burner head. as shown in FIG. ,22. Both the inlet pipe and surrounding conduit 150 are extended through an opening 149 in the rear wall of housing 166. Also, inlet pipe 148 may be supported toward its rear end on a block 151 which in turn may be supported by struts 152. extending longitudinally from the A coolant may be supplied from a suitable source (not shown) through a pipe 153 extending longitudinally of conduit 150 and threadedly received in the rear wall of the burner head 89 at a point to one side of the threadedly received end of oxygen-fuel inlet'pipe 148. The coolant may be discharged from the burner'head, after circulating through the cast manifold thereof, in a manner tobe 7 described hereinafter, through a passage 154 in conduit conduit 150 and is secured 'at its forward end in a mounting bracket 158cm the top wall of housing 106. As 9 shown in FIG. 21, a reduced portion atthe forward end of the rod 157 is received between upper and

lower'clamping members

159 and 160, releasably held in interfitting relation by pins 161. The adjusting rod 157 is provided with a threaded portion at its rear end which is received in a'bracket 162 mounted above conduit 150.

. 'Flange1163 (FIG. 22) on the side walls of housing'106 at the front face thereof are provided with bearing sleeves 164 in their outer'legs. Rods 165 extend rearwardly from wing portions 166 at each side of the burner head 89 and are slidably received in the bearing sleeves 164 of the housing 106. Thus, a rotative movement of adjusting rod 157 will result in the movement of the burner head inwardly or sired.

Turning now to theconstructionof each of the burner outwardly of its mounting means, as de-' 13 heads 89, and with reference to FIGS. 21 to 27,

lower walls

167 and 168 thereof are disposed angularly to one another to direct flames from the upper and lower rows of

nozzles

104 and 105, respectively, in proper impinging relation to the marginal edge portions of

glass sheets

38 and 39. A series of passages are provided interiorly of the burner head for the proper distribution of the oxygenfuel mixture from inlet pipe 148 to the individual nozzles 169. Another series of passages are provided for distributing the coolant from pipe 153 through the burner head, in substantially surrounding relation to the oxygenfuel passages, to passage 154.

Passage 170 extends horizontally and transversly of the burner head 89 as a continuation of the threaded socket for oxygen-fuel inlet pipe 148 to a point just short of the front wall of said burner head. A passage 171 is bored vertically from the upper wall of the burner head to intersect said threaded socket and extend downwardly therefrom to a horizontally and longitudinally extending distributor passage 172 for the lower row of nozzles Hi5. Threaded outlet passages 173 project downwardly from distributor passage 172 and perpendicular to the lower Wall 168 of the burner head at equally spaced locations along the length thereof to provide sockets for threaded shanks on each of the nozzles D39 of the lower row 165.

Passage 174 is bored upwardly from and perpendicular to the lower wall 167 of the burner. head 89 to intersect with the end of horizontally extending passage 17%. Distributor passage 175 for the upper row of nozzles extends horizontally of the burner head and parallel to distributor passage 172 to cross the passage 174 at a point below passage 170. Outlet passages 176 (FIG. 22) project downwardly from the distributor passage 175 in parallel relation to passage 174 at equally spaced locations along said distributor passage and are threaded at their lower ends similarly to the lower end of the passage 174, to receive the shanks .of the nozzles 159 of the upper rows 164.

As best shown in FIG. 21, the nozzles 1139 of the upper row 184 are spaced apart from one another a distance equal to that of the spacing between the nozzles of the lower row 195. As well, the nozzles of the upper row are staggered with relation to those of the lower in such a manner that the impinging frames from said upper and lower rows of nozzles will provide a substantially continuous, longitudinally extending flame to the marginal edge portions of the

glass sheets

38 and 39 moving therepast.

Dealing now with the circulation of the coolant through burner head 89, :it can be seen that a short passage 177 extends inwardly as .a continuation of the threaded socket for coolant inlet pipe 153 in the rear wall of said burner head. Another short'passage 173 (FIG. 24) is bored vertically from the upper wall of the burner head to intersect at its lower end with the end of horizontal passage 177, and is intersected at its upper end by a horizontally extending distributor passage 179 which is bored from the rear wall of the burner head to a point just short of the front wall thereof.

A series of passages, consisting of a relatively large passage 1'89 and

smaller passages

181 and 182 extend horizontally and longitudinally from distributor passage 179 in a direction away from the oxygen-fuel passage 170. Each of said passages maybe bored parallel to one another and in properly spaced relation from a side wall (rightmost in PKG. 22) of the burner head. At points just short of said side wall, another series of

passages

183, 184 and 185 (FIG. 22) may be bored vertically through the upper wall of the burner head to intersect .

horizontal passages

180, 181 and 132, respectively.

Passage 183, corresponding in diameter to passage 180, extends downwardly therefrom to a point just short of lower wall 168 of the burner head where it connects with a relatively smaller passage 13:; extending horizonoases lid tally and longitudinally the entire length of the burner head. At its connection with the smaller passage 1%, vertical passage 183 also leads to a similar passage 187 through a short passage 138 (FIG. 24) which may be bored from the rear wall of the burner head parallel to lower face 163 thereof. Thus, passages 136 and 1 87, disposed on opposite sides of the lower row of nozzles, may be bored through the entire lengths of the burner head.

The opposite (leftmost in FIG. 22) ends of passages i185 and 187 are connected by a short passage 139 (P16. '25) corre'sp-ondingt-o passage 183 at the opposite end of the burner head, which leads to a vertically bored passage 190, corresponding to passage 1%. Toward the upper end of passage 1% adjacent the upper wall of the burner head, a passage 19 extends inwardly and horizontally therefrom, in substantial alignment with passage 1%, and intersects at its opposite end with a collecting passage 192. (FIG. 26), which extends transversely of the burner head substantially parallel to passage 17% at the side thereof opposite from the passage 177.

Vertically

bored passages

184 and 185 extend to points just short of the lower wall 167 of the burner head 89 and intersect, respectively, with one end of horizontally and longitudinally extending passages 193 and 194- disposed at opposite sides of the upper row of nozzles llld. Similarly to passages 1% and 137, at opposite sides of the lower row of nozzles,

passages

193 and 194 may be bored through the entire length of the burner head. Just short of the opposite side wall (leftmost in FIG. 22) of the burner head, the opposite ends of passages 193 and ti -'9 intersect, respectively, with vertically bored passages 195 and 1%, corresponding to

vertical passages

184 and 135. The passages 195' and 1% are intersected by one end of horizontally and inwardly extending passages 197 and 198 (FIG. 25), respectively, which are in substantial alignment with

passages

131 and 182 extending from distributor passage i179. The opposite ends of

passages

197 and 198 connect with collecting passage at points outwardly (rightmost in FiG. 26) of passage 191.

The collecting passage le -'2 may be bored from the rear wall of the burner head to a point adjacent the front Wall threof to accommodate intersecting

passages

191, 19 7 and 198. A passage 1% may be bored vertically from the top wall of the burner head to intersect with and extend below collecting passage 3192, as shown in FIG. =26, a distance sufiicient to permit horizontally disposed coolant outlet passages Ztlti to connect the lower end thereof to a portion of passage 154 in conduit 15% adjacent recess in the rear wall of the burner head into which said conduit is fitted.

Thus, each burner head 89 comprises a cast manifold having a first series of passages from which an oxygenfuel mixture may be distributed to two rows of nozzles on the lower walls thereof and a second of passages through which a coolant may be continuously circulated insubst antially surrounding relation to said first series of passages. For example,

coolant passages

193 and 19 are disposed along opposite sides of the entire length of oxygen-fuel distributor passage as well as the passages 171 to the upper row m4 of nozzles. Similarly,

coolant passages

186 and 187 are disposed along opposite sides of the oxygen-fuel distributor passage 172 and the passages 16% to the lower row of nozzles.

As previously described, each of the passages may be bored from the walls of the burner head permitting said head to be integrally cast. The outer openings of said passages may be plugged in any suitable manner, and all but the rear walls of the burner head may be covered with a thin metallic coating 2%..

As mentioned previously, a dehydration hole 42 is disposed toward one corner of one of the glass sheets. This hole serves, during the passage of the marginally sealed glazing unit 31 from the second sealing area B and through the annealing area C, as a breather per- V 169hare played therealong in 'the manner described,

varying temperatures. in the furnace 34. Upon removal. .of the marginally sealed unit from the furnace, the

space 41 may be dehydrated and the hole 42 hermetically sealed to ,seal ofisaid space in its dehydrated condition. Anumber of different well known processes may be used in this final step of dehydrating and hermetically. sealing the space between the

glass sheets

38 and 39, and the size and shape ofthe hole 42 will generally depend on the particular process selected. However, since none of these processes forms a part of this invention; any suitable means may be employed.

Reviewing now the entire process which spaced sheets of glass may besealed'around their marginal edges to produce anhermetically sealed glazing unit 31, initially the marginal edge portions of a sheet of glass 3? areplaced on the upper edges of the upper rim 59 of tray 48. Arms 59 of the trayare then swung into supporting position such that the marginal edge portions of another sheet 38 may be supported on the ledges 62. of said armsin properly spaced and vertically aligned relation above the sheet 39..

The upper surface of the upper sheet 38 may besha'ded with glass cloth or the like and the tray'4$; with both sheets supported thereon, placed in the preheating compartment .33 insuch a manner as .to be in substantial alignment with opening 35 in'the furnace 34 andthe spacebetween rollers 141 as well as the space between a the first set of opposed burners 37 at sealing area A. The temperature of the compartmentfifs is maintained at about 5 75 degrees Fahrenheit to properly preheat the

glass sheets

38 and 39 prior to theirentry into the furnace. Of course, as mentioned previously, the preheating of the glass sheets may be performed in the forward end of the furnace, eliminating the need for a separate compartment.

' In any case, however, as the tray dfi is moved forwardly on conveyor 32 and 'past aligning rollers 141;

the

glass sheets

38 and 35 are progressively raised to a temperature slightly short of the annealing temperature which, in most cases, is about 1000 degrees Fahrenheit.

That is, the sheets are'heated to a level just short of their 7 strain point in moving into the first sealing area A.

As the tray moves into engaging relation with the opposed burners 137 of the first sealing area A,'which of'this' invention by at 90 degrees to its path through the first seaiingarea A. 1 In this manner; the unfused pair of oppositemarginal edge portions willbe aligned with the direction of movement of the tray and the fused portions will be perpendicular thereto; Thus, with opposed burners 37 of the second sealing area B in properly adjusted position j of sealing area B,

glass sheets

38 and 39 will be sealed entirely "around their marginal edge portions to, form enclosed space 41. As the marginally sealed sheets move into the second corner of furnace 34-between sealing area B and annealing area C, a directional transferring device, similar to the onedisposed in the first corner of the furnace, will cause the movement of tray 48 to be changed another 90 degrees. 3 a

In its oriented positiointray dfiwill be moved on the third section of conveyor 32 through the annealingarea C- In'the' annealing area, thete'inperature of the furnace 'is; accurately controlled in'such a'rnanner that it will be caused to drop gradually from "about 960 degrees Fahrenheit at the end of said area adjacentsealing area B to about 295 degrees adjacent theexitfid of the furnace glass sheets for a- -purpose well known in the'art. V, f I V Of course, as the marginally sealed unit Slis removed from the conveyor 32 at the end of the furnace, it may be moved to any suitable'location for dehydrating the space il'therebetween and hermetically sealing hole 42, p as previously mentioned.

It is to be understood that the forms of the invention disclosed herein are to be takenzas. the preferre'd embodiments thereof, and that various changes in the shape,

- size and arrangement of parts'may'be resorted to withhave been properly adjusted in themanner described,

the opposite sides of the lower rim 4%! of the tray will engage" rear rollers 92 on the opposed burners to spread said burners from the normalto theoperative position. As tray- 48 moves forwardly out of engaging relation with the first set of burners, said burners will return or right themselves to the normal'position. During the movement of the tray past the first set of burners when they are disposed in the operative posi tion, the marginal edge portions of the pair of opposite sides of the glass sheets adjacent said burners will be "progressively fused, as the arms 59 'sup'porting said op:

posite marginal edge portions of the upper sheet 38 are knocked out and flames from burner head nozzles As the tray 48 moves from the'first sealing area A to I the directional transferring mechanism at thefcorner between said first sealing area and the secondsealing area B, upper sheet 38 will be properly supported above lower sheet 39 onone pair of opposite sides by the marginal edge portions of both sheets which have been almost instantaneously fused atthe first sealing area to form second sealing area B, it too will be traveling in a path I another glass sheet, moving said marginal edge portions out departing from the spirit of the invention.

We claim: 7 M. l. A method of producing multiple sheet glazing units, which comprises supporting the marginal edge portions of one sheet of glass in spaced relation above those of of the sbejets'as aunitrpast a heat source whichheats said marginal edge portions and causes them to be fused to one'another, and progressively removingj'a' portion of the support for the upper sheet nearest the heat source prior to movement of the previously supported marginal edge portions of said sheets past said heat source while retaining snpport for the sheet along areas farther re-. moved from said heat source until the marginal edge portions are sealed substantially along their entire length.

' 2. A method of producing multiplesheet glazing units, which comprises supporting a'marginal edge portion of an upper sheet of glass in spaced and outwardly project? ing relation above that of a lower sheet, directing a flame from a concentrated heat source downwardlyonto the marginal edge portion of the upper sheet in a direction substantially perpendicular to the plane of said sheet and in substantial alignment with the edge of said'lower sheet, and simultaneously directing an additional flame downwardlyonto the. marginal edge portions of said'lower sheet at an angle to the plane of said lower sheet.

3. A method of producing multiple sheet glazing units which comprises, supporting the marginal edge portions of one sheet of glass in spaced relation above the corresponding portions of another glass sheet, movingthe marginal edge portions of both of'fsaid sheets at'opposite sides thereof past a'group of concentrated'heat sources to cause said edge portions to be sealed together, removing the supports for said marginal edge portions of the upper sheet just prior to their movement past said group of heat sources, orienting said sheets to sequentially dispose the other marginal edge portions of both sheets at the other opposite sides thereof in alignment with other groups of concentrated heat sources, sequentially moving said other marginal edge portions of both sheets past said other groups of concentrated heat sources to cause said other edge portions to be sealed together, and sequentially removing the supports for said other marginal edge portions of the upper sheet just prior to their movernen past said other groups of concentrated heat sources.

Reterences Cited by the Examiner UNITED STATES PATENTS 1,448,351 3/23 Kirlin 65-34 2,194,755 3/40 Kell 65-47 2,389,360 11/45 Guyer et a1. 65-40 2,24,979 1/ 53 Clever 6523 2,671,987 3/54 Iendrisak 65-158 2,761,249 9/56 Olson et a] 65152 1 DONALL H. SYLVESTER, Primary Examiner.

CHARLES A. HODGES, ARTHUR P. KENT, MOR- RES 0. WOLK, Examliners.

ONITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 202,494 August 24, 1965 John A. Woods et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the drawings, Sheets 1 to 7, line 3, for "July 25, 1962", each occurrence, read July 25, 1952 column 14, line 55, after "second" insert series Signed and sealed this 5th day of April. 1966.

( L) Attest:

ERNEST W. SWIDER Attesting Officer BRENNER Commissioner of Patents

Claims

1. A METHOD OF PRODUCING MULTIPLE SHEET GLAZING UNITS, WHICH COMPRISES SUPPORTING THE MARGINAL EDGE PORTIONS OF ONE SHEET OF GLASS IN SPACE RELATION ABOVE THOSE OF ANOTHER GLASS SHEET, MOVING SAID MARGINAL EDGE PORTIONS OF THE SHEETS AS A UNIT PAST A HEAT SOURCE WHICH HEATS SAID MARGINAL EDGE PORTIONS AND CAUSES THEM TO BE FUSED TO ONE ANOTHER, AND PROGRESSIVELY REMOVING A PORTION OF THE SUPPORT FOR THE UPPER SHEET NEAREST THE HEAT SOURCE PRIOR TO MOVEMENT OF THE PREVIOUSLY SUPPORTED MARGINAL EDGE PROTIONS OF SAID SHEETS PAST SAID HEAT SOURCE WHILE RETAINING SUPPORT FOR THE SHEET ALONG AREAS FARTHER REMOVED FROM SAID HEAT SOURCE UNTIL THE MARGINAL EDGE PORTIONS ARE SEALED SUBSTANTIALLY ALONG THEIR ENTIRE LENGTH.