US836439A

US836439A - Process and apparatus for drawing sheet-glass.

Info

Publication number: US836439A
Application number: US32554306A
Authority: US
Inventors: Irving W Colburn
Original assignee: Individual
Current assignee: Individual
Priority date: 1906-07-10
Filing date: 1906-07-10
Publication date: 1906-11-20
Anticipated expiration: 1923-11-20

Description

No.,836,439 PATENTED NOV. 20, 190

' I. w. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULY 10. 1006.

0 SHEETS-SHEET 1 2/911?" use: Q!

No. 836,489. PATENTED NOV. 20, 1906. I. W. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULYlO. 1906.

6 SHEETSSHEET 2 We 131 uses fiaw/ a. 5444;

'No. 836,439. PATENTED NOV. 20,1906. I. W. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULY 10. 1906.

6 SHEETS-SHEET 3- 23 i 511 eons 9km; A

PATENTED NOV. 20, 1906.

I. W. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULY 10. 1906.

8 SHEETS-SHEET 4.

- LWZM} wlw y/(r7 v M4) 22" Mom 14; lb

No. 836,439. PATENTED NOV. 20, 1906. I. W. OOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED .TULY10,1906.

6 SHEETS-SHEET 5 No. 836,439. PATENTED NOV. 20, 1906. I. W. COLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLIOATION FILED JULYlO. 1906.

6 SHEETSSHEET 6.

avweukw witnesses awa/flfia film, @Mm M; km;

27' umm UNITED S ATES PAT NT onn on.

invmo. w looL URN, or FRANKLlN, PENNSYL ANIA. v PROCESS .ANDVAPPV-ARATUS Foe DRAWING SHEET-GLASS."

Specification of Letters Patent. Application and July 10. 1906. seen No. 325,549.

Patented Nov. 2c, 1906.

new 'and' useful Improvement in Processes and] Apparatus 'j for Drawing Sheet-Glass,

which'improvement is fully set forth-in the following specification.

This invention relates to the artof drawing sheet-glass, and is applicable to the drawing of sheets :of fixed len th, as Well as to the continuous drawing of t e glass in sheet form.

When an effort is made to drawa sheet of glass from amass of molten glass, one of the great difficulties to be overcome is the tendenoy of the started sheet to rapidly narrow to a string or cord. Another ifliculty lies .in the fact that it is extremely difficult to avoid the formation 'ofiwave-hke lines or striee u on the faces or surfaces of the sheet of g ass as it is drawn, which lines or striee ver-y materially injure the market value of the glass and, in' fact, render it practically unfitfor a great var ety of uses. experienced in the drawing of sheet-glass, and particularly in the. 'dr'awing of a continuous sheet. hes in the fact that the mechanism employed in handling the sheet, especially'at a time when the sheet is at all softened by the influence of heat, must-move in absolute unison with the movements of the sheet at all times, to the end that there may be no slipping action 'or.r'elative movement between finish ofthe glass;

any portions of the mechanism and the surface of the sheet with which such mechanism may be in contact, since such slipping action or relative-movement between the two surfaces would be liable to slightly mar the fire- The object of the present invention is to provide a method and means whereby a sheet of glass of uniform width can bedrawn from a mass of molten glass and whereby the formation of wave-like lines or striee upon the surfaces of the sheet, as well as the marring effect due to contact with. any .of the mechanism, may boavoided In previous a plications filed by myself and Edgar Wash urn as i'omt inventors, said applications being Seria No. 248,288, filed March 3, 1905, and Serial No. 304,555, filed March 6', 1906, there is disclosed a method and apparatus for overcoming the narrowing tendency of the sheet during the drawing operation, which method, generally stated, conthe molten mass drawing" a sheet lateral movement in oppos te directions and away from the two edges A further difficulty sists in imparting. to the surface-portion'of during the. operation of of the sheet. This is accomplished byimmersing moving bodies, such as revolving spheres. in the molten mass adjacent to the edges of the sheet being drawn and revolving them in such a direction that their adjacent surfaces move upward and outward.

The formation of ribs or striae upon the surface of the drawn sheet of glass may be and probably is due to a variety' of causes. Among these may be mentioned the tendency ofthe surface of the molten glass in the working chamber or pot when the same is exposed to the 'coolmg influences of the external atmosphere to take or receive impressions iron the roughened side walls of the working chamber or pot. This is particularly true if the point where the molten glass leaves the walls or other part of the receptacle be but a few inches from the point where the glass enters the sheet. Moreover, the chilling influence .of the atmosphere itself. is liable to-oause the surface of the molten glass to more or less wrinkle or form into minute waves or ridges. These are some, though doubtless not all, of the causes ofthe formation of ribs or striae upon the surfaces of the sheet. Now during the operation of dra'winga sheet of glass the tendency of the surface portion of the molten mass in the working chamber or pot is to move slowly toward and into the sheet being drawn, so that any wave-like lines upon the surface of the molten mass would ultimately appear in the surface of the drawn sheet in the form of ribs or striae.

' Ihave discovered that if during the operation of drawing a sheet of glass 'fromthe mol-.

ten mass a part of the surface portion of the molten mass has movement imparted to it in opposite directions and away from the two facesof the sheet being drawn the formation of the ribs or striee in the surfaces of drawn in 't e working chamber or pot should be heated to a degree above that which itis desired the surface of the mass shall possess at the time when it enters the sheet and toward the, edges of only a limited area'of the surface of the-mol- I ten mass should be exposed to the cooling in fiuences of the atmosphere at or adjacent to the point where the sheet is being drawn; By thus raising the temperature of those portions. of the molten mass somewhat re mote from the sheet being drawn and by regulating the area of the surface of the molten mass exposed to the cooling influences of the atmosphere it becomes possible to present the glass to. the formative point at a proper temperature and in the proper condition for awing into a sheet Without the formation the objectionable ribs or striae, and .when this step is performed in conjunction with that of imparting movement in opposite directions to a part, of the surface portion of the mass away from the two faces of the sheet being drawn the sheet will be perfectly free from such ribs or strise.

One part "of the im' en'tion in the present instance,therefore, resides in ,a method of drawing a sheet of glass from a ma of molten glass and simultaneously imparting movement to a part offthe surface of the molten mass away from the two faces of the sheet being'drawn, and, furthermore, the invention residesfina method of superheating portions of the molten mass remote from the point where the sheet is bein drawn and I then limiting the area of the mo ten mass exposed to" the cooling'infiuences of the atmosphere. v Preferably each of the above-mentinned steps are, racticed jointly-that is, motion'isimparted to a part of' the surface of them'olten mass in opposite directions and awayai rom the two faces of; the sheet being drawn, while at'the same time remote portions. of the moltenmass are superheated and the area ofthe molten. mass exposed to the cooling influences of the atmosphere is controlled Within the desired limits. By superheated as herein employed is meant the heatin of thexsurface portion of the mass to a egreeabove that which it is desired the glass should have at the time when itr-assumes sheet form or at the time when it passesfrom the molten mass into the Sorm of a sheet. As one of the essential steps in drawing the-sheet of, glass the method also includes ho ding the sheet to uniform width in any effective- 'way, as by imparting movement to the surface portion of the molten mass. near the she'ets edges in a direction away from the medial" line of the sheet and the sheet during the drawing operat1on.

For the urpose of im arting movement to. the su ace portion 0 the molten mass on that portion of away from the surfaces or faces of the sheet during the drawing operation I preferably employ two refiractory rollers, with the lower portion of their peripheries immersed in the surface of the molten mass in, the working chamber or pot, and slowly revolve these rolllying between the ,rollers. Preferably,

though not necessarily, the two rollers are revolved in o posite directions with their adjacent su 'ac'es moving upward. They may be revolved, however, with their adjacent surfaces moving downward; The use of such rollers serves not only to impart movement to a part of the surface of the molten mass away from the faces of the sheet during the drawing operation, but serves also to determine the area of the surface of the molten mass in-the. working chamber or pot which is more or lesstexposed to the cooling influences of the atmosphere, and the superheatin referred to above occurs the surface of thcmolten mass to the rear of said rollers that is, on the sides of said rollers away from the sheet being drawn. This superheating may be accomplished; in any suitable manner, as by directing heated ases of combustion against the glass and rol ers on the rear side ofsaid rollers.

uniform Width I may employ bodies ofrefractory material immersed in the molten mass adjacent to the edges of the sheet being drawn therefromand movin in such a man.- ner as to impart an outwar .motion to that portion of the surface of the molten mass lymg immediately adjacent to the edges of the sheet. These bodies for holding the glass to its uniform width may be of any suitable construction, such as revolving spheres shown in the joint 1. plication of lnyself and Edgar Washburn, eria-l No. 238,592, filed December 28, 1904, or they may be in the form of hooks ofrefraetory material, such as shown in. the joint a. plication of myself and Edgar Washburn, S hrial No. 304,555, filed March 6, 1906. I

If a sheet of glass be drawn from t-he'r'n'o'l-v ten mass lying between the rollers aforement'ioned and means be employed to impart an outward movement to thatportionofthei'sur face of the molten mass lying immediately adjacent to the edges of the sheet,thefoll'owing action of the molten glass willbe observed: The molten glass at and justbeneath the-surface adjacent to the edges of the sheet will move away from the center line of thesheet+ that is, outward-thus serving to hold the sheet to its full width. As the sheet of glass moves upward there is drawninto'thesheet some of the surface portion offthe molten mass immediately adjacent to the two faces of the sheet and also some of the-molten glass beneath the surface. At 'th'e same til-no the two rollers on the opposite sides of the sheet of glass also serve to draw some of .he

surface portion of theniolten mass lying between the roller-sand the sheet of glass away from the sheet.

It will thus be seen that the For the purpose of holding the sheet to its too eaease result of the combined action of the drawing of the sheet and the movement of the rollers is the skimming, as it might be called, of the surface portion of the molten glass lying between the two rollers, thereby exposing a fresh portion or a new surface of molten glass to the cooling eflect of the atmosphere. This action is continuous, and the result is a continuous supply of fresh glass to the surface, which in turn is submitted to the cooling action. of the atmosphere before it passes into the sheet. A further'action of the rollers is to bring a supply of fresh hot glass into the area lying between the rollers and the sheet being drawn. The glass which is skimmed from the surface b the rollers and carried over by the rollers is subjected to the superheating action at the rear of the rollers and is melted down, so as to free the rollers from the mass of glass clinging thereto and place such glass in proper working condition. The slow movement of the rollers, hereinafter referred to, afford s ample time forthis melting down of the glass carried over by the rollers. In order to secure the desired results, it is necessary that the speed with which the sheet of glass is drawn and the speed with which the rollers are revolved should be properl regulated. This can be determined y experience and will vary with the conditions of each particular case, depending upon the temperature of the molten mass in the working chamber or pot, the temperature of the external atmosphere, the thickness of the sheet to be drawn, 8w. Generally speaking, the speed at which the sheet is drawn will vary from six to thirty inches per minute, and the revolution of the rollers will vary from one revolution in ten minutes to one revolution in thirty minutes, and for this purpose there is of course introduced into the machine suitable mechanism for adjusting the speed of draft of the sheet and speed of the rollers. It will thus be observed that there occurs a continuous skimming of the entire surface of the working chamber between the rollers, and as this skimming action occurs fresh glass continuously comes up from below at some point between the sheet and the roller, which in turn affords a'new surface to be subjected to the cooling influence of the atmosphere, which is in turn skimmed and passed into the sheet. This action is the same between each roller and the sheet being drawn. In other words. fresh glass is coming up from below at two places-one between each roller and the sheet. The skin or the surface of the molten mass becomes the skin or surface of the sheet being drawn, and it is this skin or surface that must he kept free from the ribs or striae.

It will be understood that in the action above described all of the various steps are proceeding simultaneously that is, glass is being drawn from the surface by the moving sheet and by the rollers and fresh glass is coming up to form a new surface, all of these proceeding simultaneously. Of course the sheet of glass being drawn and the rollers affect not onl r the immediate surface portion of the mo ten mass, but also act to draw glass that is beneath the immediate surface, the rollers also bringing hot glass to the working part of the pot between the rollers. Moreover, this supply of hot glass keeps the temperatures even and allows an even thickness of glass to be drawn. This furnishing of a new supply of hot glass from the back of the rollers to the surface portion of the mass between the rollers is one of the im ortant functions of the rollers. By revolving the rollers at the slow rate .mentioned above ample time is afforded to melt the glass from the rear sides of the rollers, and, moreover, this slow movement avoids the possibility of air-bubbles being carried down by the rollers into the molten glass. This is important, as the presence of such bubbles would result in blisters on or in the drawn sheet of glass.

In the continuous production of sheetglass the most convenient means for handling the sheet consists of an apparatus for drawing the sheet vertically and then turning it from a vertical to a horizontal position, the turning being made overa suitable bending-roller, which is positively driven so as to revolve in the same direction in which the sheet of glass is moving and is intended to revolve at the same rate of speed as the sheet moves, to the end, that there may be no relative movement between the surfaces of the roller and of the sheet of glass. In practical operation, however, it has been found almost impossible to insure at all times the uniform movement of the surface of a positivelydriven roller and the sheet of glass. While the two could usually be relied upon to move synchronously, nevertheless there would at times occur certain relative movements between the two surfaces which would result in a slight marring of the fire-finish u on the glass. If the movements of the re ler are made to depend upon the movements of the sheet of glass, this relative movement be tween the roller and the sheet will be entirely obviated and the marring action due to such relative movement avoided. ln some cases this may be accomplished by mounting the bending-roller as an idler-roller on antifrictional bearings'and causing it to be revolved slowly b the frictional contact of the moving sheet of glass, as shown, (lescribed, and claimed in i he aforesi-iid application Serial No. 304,555. l have found, however, that in many instances. the weight of the roller is so great and the conditions under which the glass is drawn vary to so great an extent that it is desirable to utilize some positively-driven mechanism in driving the lOO roller and at the same time control the revolu' tion's entirely by the movement of the sheet of glass.

Generally stated, therefore, my invention onsists:

First. In a method'of drawing a sheet of glass by preparing a molten mass of glass,

drawing a sheet therefrom, and sii'nultaneously imparting movement to a part of the surface portion of the molten mass in. o )po. site (lll'OClLlOHS and away from the faces of the sheet-durinp the drawing operation;

Second. The invention consists in su erheating the surface portion of the mo ten mass remote from the'sheet being drawn, re-

tion of themolten mass away from the e gas of the sheet during the drawing operation, though some other means for holding the sheet to uniform width may be employed, if desired.

Third. The invention consists in'means for drawing a sheet of glass from a mass of molten glass, combined with means for iniparting movement to the surface portion of the mass in oppositedirections and away from the faces of the sheet being drawn. Preferably the means for thus imparting motion to the surface of the molten mass consist'of a pair of arallel refractory rollers hav ing their perip ieries partially lflllllkISQd in the molten mass and revolving in opposite directions, the sheet being drawn from the molten mass lying between the rollers. I prefer to have the rollers revolve so that their adjacent surfaces move upward and outward, thouplh they may in some cases be re' volved in t e opposite direct-ion.

Fourth. The invention consists in means for superheating the surface portion of the molten mass remote from the sheet being drawn, combined with means located between such superheated portion and the point where the sheet is drawn, which means at to submerge the surface portion of the molten mass and -to limit the area of the molten mass which is ex osed to the cooling influences of the externaatmosphere. The means for superheating the remote portions of the mass may consist of any means for supplying gases of combustion at a high temperature to the surface of the molten masssuch, for example, as suitably-constructed burners. Preferably the means for submerging the surface of the mass at a mint between thesuperheatcd portion and the point of the sheet and also the means for limdrug the area of the molten mass exposed to the cooling influences of the atmos here may 2 be one and the same structure HIM may also .be identical with the ineans'forimparting movement to a. part of the surface portion of the mass in opposite directions and away from the faces of the sheet during the drawing operation, and as here shown these three sets of means are all combined in one and are illustrated in the shape of a pair of refractory rollers having their peripheries partially immersed in the molten mass and revolving in opposite directions.

Fifth. The invention consists in a bending; roller over which the sheet of glass is bent or turned during the drawing operation, which roller receives the power necessary to set it in motion from the frictional contact of the sheet of glass acting in conjunction with positive power mechanism. Usually bendingroller's of the character referred to are quite heavy, weighing considerably more than half a ton; If such rollers are mounted on delicate antifrictional bearings, asdescribed in the aforementioned application Serial No.

304,555, the frictional contact of the sheet in most cases will be sufficient toimpart revolution to the roller, which revolution will be substantially uniform with the movement of the sheet of glass. I have found, however, that with. the varying conditions, such as 00-, our when sheets of different thickness and different degrees of temperature, &o., are drawn, there is an occasional relative movqv .ment between the surface of the roller and of the sheet of glass if reliance is placed entirel upon the frictional contact of the sheet wit the roller to drive the latter. I have therefore devised means whereby power may be applied to the shaft of the ending-roller, which power, however, just falls short of bein suflicient to impart revolution to the ro ler. This is accomplished, for example, by means of a friction-clutch inter os'ed between the driving-shaft and the r0 ler-shaft, in which the friction is adjusted to such a rio point that the clutch will slip and fail to drive the roller, but is nevertheless so great thatzwith very slight additional ower applied the roller will readily revo ve. This additional power is supplied by the frictional contact of the sheet of glass with the roller. By this means the g'reater' portion of the power necessary to drive the roller is obtained from asuitable'source of power, and reliance is placed upon the sheet merely to add the overbalancing amount necessary to produce the revolution.

Finally, the invention consists in certain detailed methods of procedure and constructions of apparatus, which will be hereinafter.

more fully described and then pointed out in the claims.

It will be apparent to thoseexpert in the art that the inventive ideas hereinbefore described are capable of finding expression in methods .varying somewhat in detail and that the inventive idea involved in the mechanism is capable of receivin a variety of mechanical expressions. In t e accompanyin drawings, for the purpose of illustration on y, I have disclosed one form of apparatus which may be'employed but suchillustration is not to be regarded-as defining the limits of the invention, j reference being bad to the claims for that urpose.

In said drawings, Figure l is a brokendetailed perspective view of apparatus employed in practicing the invention, and Fig. 2 is a detailed view illustrating aslightlymodified method of procedure. Fig. 3 is a side elevation of the machine, illustrating the means of applying power to the various parts of the apparatus. Fig. 4 is a central vertical longitudinal section of the apparatus. Fig. 5 is an elevational view of the side opposite to that shown in Fig. 3. Fig. 6 is a vertical transversev section on the line 6 6, Fig. 4. Fig. 7 is a broken plan view, partly in section, of that portion of the apparatus lving immediately over and contiguous to the workin chamber or pot. Fig. 8 is a sectional (18- -ta1l illustrating a portion of the-apparatus for driving the bending-roll.

In the drawings like reference-numerals indicate like parts, and referring to Figs. 4 chamber or furnace of and 6, '1 is a melting any suitable or usua construction, and 2 is a workin chamber or pot in communication therewith throu l1 asuitable opening or openings 3, provided in the lower portion of a bridge wall 4. Preferably there are two openings 3, one on each side of the working c amber or ot, so that the glass passing from the me ting-furnace 1 will enter the working chamber 2 adjacent to or beneath the edges of the sheet .beingdrawn. suitable or usual means for heatin the working chamber or pot 2 may be emp oved, and as the specific construction of suc ent invention the same are not shown in the drawings. Mounted within the confines of the working chamber 2 are a pair of oppositely-disposedrollers 5 5, composed of any suitable refractory material, such as a suitable clay. These rollers are mounted u on substantially parallel hollow shafts 7 7, est shown in Figs. 1 and 4,) which shafts have their bearings upon the exterior of the working chamber, the shafts extending through the walls of said chamber, as shown in Fig. 7. The hearings of these shafts are arranged so that the shafts may be each adjusted at each end both in a vertical and horizontal direction. Preferably there are mounted on the su porting structure of the machine suitable frames 8 8, Fig. 5, arranged to slide horizontally on a suitable bearing plauor plates means .does not-form any essentlal part of the pres- 9. Screw-shafts 10, one for each frame, are mounted to turn in bearings onplate 9, but withoutlon itudinal movement with relation to said bearings, such movement being restrained, as by a collar 11 or other suitable means. These'screws 10 engage corres 0nding female threads on the frames 8 an may be revolved by any suitable means, the direc tion of movement of the frames depending upon the direction in which the screws are turned, as. will be readily understood. Sliding vertically within the frames 8 are bearingboxes 12 12, and projecting vertically upward from said boxes are screws 13, which pass through the 'top portion of the frames 8 and are engaged by nuts bearin u on the top of the frames and having han ieels 14 rigidly secured thereto, so that by revolving the hand-wheels the bearing-boxes may be elevated or depressed. Each of the shafts 7 has an enlarged bearing-surface 15,(see Fig. 1,) corres ending in shape to a portion of a sphere, w ich rests in a corresponding bearing in boxes 8, which boxes are constructed in two parts in order to admit of the assemblage of the elements. This form of bearing is one well known in mechanics and rovides for the proper horizontal and vertica adjustment of the shafts one at a time and indeendently at each end of each shaft without imparting any strain to the parts, and also permitting of easy movement, even though the adjustments at each end of either shaft maiy not be absolutely identical.

or the purpose of preventing the shafts 7 from becoming unduly heated by the intense heat to which thev are subjected within the working chamber 2, these shafts, as before stated, are hollow, as plainly indicated in Fig. 4, and water is circulated. through the shafts, the same being conducted into the shafts through flexible couplings 15, Fig. 1, and emerging through coup ings '16.

The mounting of the refractory rollers 5 with relation to the mass of molten glass in the working chamber is such that the lower peripheries of the rollers are more or less immersed within the surface of the molten glass, and these rollers are driven at the same rate of speed, but in opposite directions, the direction of revolution of the two rollers preferably being such that their adjacent surfaces move upwarcl, as indicated by the arrows in Fig. 1. Any suitable mechanism for thus driving the two rollers in opposite directions, but at the same rate of speed, may be employed. As here shown, (see Fi s. 3 and 6,) each of the shafts is provide with a sprocket-wheel 17. Power drawn from any source is conveyed by variable-speed connections, asa friction-cone 18, to a shaft 19, having thereon a worm 20, engaging a wormgear 21 on shaft 22. Shaft 22 carries a gear 23 keyed thereto and a sprocket-wheel 24. Gear 23 meshes with a gear 25 keved to a shaft 26, which shaft carries a sprocket-gear .27 of the same dimensions as the sprocketgear .24 on thr shaft 22. It willthus be seen that the two

shafts

22 and 26 are driven in opposite directions, and that'therefore the sprocket-wheels on these shafts turn in opposite directions. A sprocket-chain 28 passes from sprocket-wheel 24 over sprocket-wheel 17 on one of the shafts 7 and a sprocketchain 29 passes over the sprocket-wheel 27 and the sprocket-wheel 17 on the other shaft 7. Since the s rocket-wheels 1.7 are alike in dimensions ant the sprocket-wheels 24 and '27 are also alike in dimensions, it follows that the two rollers 5 5 will not only be driven in oppoiite directions, but at the same rate of s cc Mounted between the rollers 5 and in position adjacent to the edges of the sheet that is to be drawn are the devices for holding the sheet to uniform width and preventing the: narrowing tendency heretofore mentioned.

Any suitable means for this purpose will be within the scope of the present invention; but as here shown such means consist of hooks 30 of refractory material immersed in the molten mass of glass adjacent to the edges of the sheet being drawn, said hooks being provided with means for manipulatin them so as to impart movement to the mo ten mass adjacent t the edges of the sheet away from the medial line of the sheet and toward its ed es. The hooks are clamped on the ends of levers 31, Fig. 6, pivoted at 32 to swin ing links 33. By grasping the handle ends 0 the two levers 31 they may be manipulated in such a Way as to cause the hooks to dip into the molten mass of glass and move a slight distance toward the medial line of the sheet, after which; they can as slightly raised and then drawn outward toward the edges of the sheet, thereby imparting movement to the surface portion of the molten-mass toward the edges of'the sheet, and thus operate to hold the sheet to its uniform width. If desired, these hooks may be operatedautomatically instead of by hand, as shown and described in the aforementioned application, Serial No. 304,555.

As illustrated in Fig. 4, the receptacle 2 is covered over, except for a narrow slot or opening through which the sheet of glass 33 is drawn. The cover portion of the rece tacle is preferably provided with downward y-extendin lip portions 34, whose lower lines preferafhly are below the plane of the upper sides of the rollers 5 5, which rollers are placed beneath and a little bit to one side of said lips 34. The object of these downwardly-extending lips is to assist in preventing the heated gases of combustion which are directed against the molten glass on and to the rear of the rollers from passing over the rollers and injuriously affectin of glass being drawn. In addition to these the sheet I downwardly-extending lips two shields 35 35 are provided, which shields are supported on either side of the sheet of glass being drawn and parallel therewith and between the rollers5 5 and said sheet. The heated ases of combustion which pass over the rol ers5 5 and under the lips 34 34, as well as the intense heat radiated from the molten glass carried up by the rollers 5 5, would so melt down or soften the sheet of glass being drawn as to either make it draw very thin or would render the drawing of the same entirely impracticable, and the shields 35 35 are thereore supplied to protect the sheet of glass at the point immediately above where it is drawn from the destructive influences of the gases of combustion and the heat radiated om the rollers. Theseshields are preferably in the form of flat hollow chambers and are provided with means for circulating a cooling medium, as-water, therethrouh, 'Water being supplied, for example,throug pi cs 36 and carried off by pipes 37, a suita is flexible hose 38- being. attached to the said pipes for the purpose of induction and-eduction of the water. These shields 35-35 are not for the purpose of coolingeither the sheet of glass bern drawn or the surface of the molten-glass dying between the rollers. In fact, care must be exercised to avoid any material cooling of the surface of the molten mass by the action of these shields, since if any ap reciable cooling due to this cause takes p ace it is liable to materially affect the successful drawing of the sheet. In other words, the elements 35 35- are provided as shields, and shields only, to protect the sheet of lass from radiated heat from the rollers andl'the gases of combustion tpassing over said rollers. For the u-rpose o placing said shields at the proper is'tan'ce above the mol-.

ten mass to efiectual-ly perform their ofiice as shields and yet at the same time provide against placing them so near the molten mass as to exercise an appreciable cooling effect thereon these shields are so mounted that they may be adjusted both in a vertical and a horizontal direction. One very simple means for this urpose consists in resting thepipes 3c 37,wl 1 or other refractory material 39, Fig. 4. The shields may be readily adjusted toward or from the'sheet of glass along the .top ofthese refractory bricks, and their height may be adjusted by using a greater or less number of bricks under the supporting-pipes 36 37 Any suitable means may be employed for supplying the heat necessary to superheat the surface of the molten glass in the working chamber 2 to the rear of the rollers 5 5. As here shown, thatportion of the molten mass lying to the rear of the roller 5 nearest to the n-ieltingfurnace 1 is superheated by permitting the heated gases of combustionto pass 1 from the melting-furnace 1 over the top of ich support the shields, upon bricks IIO the bridge-wall 4 against the roller, and then to pass upward and outward through suitable lines, as indicated by the arrows, and into the downwardly-leading stack 40. (Indicated by dotted lines in Fig. 4.) The means for superheating the glass to the rear of the other roller, as here shown, consist. of burners 41, Fig. 1, located in'a chamber adjacent to the working chamber 2, and provided with a fine 42, through which the gases of combustion are conducted to the rear of the rollerfi, after which they are conducted by return-fines to the downwardly-leading fine 43, and hence to asuitable stack 44.

Referringto Figs. 1, 3, 4, and S, is abending-roller located in heated chamber 46 and carried on a shaft 47, \ivhose ends extend through the walls of the chamber 46 and are carried on suitable antifrictional bearings located in bearing-boxes 48. The shaft 47 is hollow and is provided with suitable means for conducting a cooling medium therethrough-for example, the pipe 49, Fig. 1,'

leadin from a source of water-supply and a sultab fe corresponding pipe at the opposite end leading to the sewer or other waste. Se-

cured to the shaft 47 is a sprocket-wheel.

over which a sprocket-chain 50 passes as well as arounda second sprocket-wheel 51 on a shaft turning in bearings 52, whicl'i latter shaft has keyed thereto a worm-gear 53, which is engaged by a worm 54 on shaft 55, turning in bearings 56 and having keyed thereto friction-disks -57 and 58. The disk 57 is fixed on the shaft and the disk 58 is free to slide longitudinally thereon, but compelled, like disk 57 to revolve therewith. Mounted loosely on the shaft 55, between the

disks

57 and 58, is a sprocket-wheel 59, over which asses sprocket-chain 60, leading to the driving-shaft 19. Bearing on the disk 57 is s ring 61, which reacts between said disk and tie flange 62 on a nut 63, threaded on the.

outer end of the shaft and provided with a hand-wheel 64. By turning the handwheel 64 in. the proper direction the spring 61 may be compressed, and hence the disk 58 I forced so as to grip the sprocket-wheel 59 with increased friction between the two disks 5? and 58.

By reference to Fig. 1 it will be seen. that the shaft .47 of the bending-roller is provided with a hand-wheel 65.

It will be readily seen that by adjusting the friction of the

disks

57 and 58 upon the sprocket-wheel 59 the same mav be brought to a point where the friction will be just below the point necessary to drive'or revolve the bending-roller 45, the friction-disks slipping on the surface of the sprocket-wheel 59. By feeling of the hand-wheel 65 and by the addition of a very slight amount of power by hand to revolve the same the'o erator can ascertain when the friction of

tie disks

57 and 58 on the sprocket-wheel 59 has reached the point where a slight additional amount of power will be suflicient to revolve the'bendingroller. It being known in advance what additional power will be furnished by the sheet. of glass as it passes over the bendingroller the mechanism. is so adjust-ed that this additional amount of power will be sufficient to revolve the roller in unison with the movements of the sheet. The best results are obtained with this frictimi-clutch device when the

disks

57 and 58 are revolving much more ra iidly than it is desired to turn the bendingroiler 45, so'that even when the'friction is suflicient in combination with the action of the sheet of glass 'to revolvethe'rollerthe friction-

disks

57 and 58 will be slipping upon the sprocket-wheel 5th When warming up the machine previous to Y beginning the operation of drawing a sheet of glass, the

disks

57 and 58 are pressed with sufficient friction against the sprocket-Wheel 59 to alone turn the bending-roller 45, and when the. machine is read for the drawing to begin the friction is eased through the handwheel 64 until the friction will be just below the point necessary to drive the bendingroller, the action of the sheet passing there over being sufficient to furnish the additional power required. 7

In order to avoidthe tendency of the molten glass to pile up at the ends 'of the rollers 5 5 and around the shafts thereof,

which tendency if continued might result in a clogging action between the ends of the rollers and the walls of the working chamber, I provide burners 66, which pass through the walls of the working chamber, preferably at a point immediatelybelow where the shafts 7 of the rollers pass through said walls, said burners being connected with the gas system to 5 by means ofv suitable piping 67. (See Figs. 1

and 3.)

Immediately to the rear of the drawingchamber 46 is a leer 68, and at the pointwhere said leer joins the drawing-chamber 46 1 10 there is a removable door or closure 69. Mounted on the rear of the drawin -chamber 46 is a drum operated by suita )le power mechanism, and around this drum is wound chain 70, carrying the bait 71 employed in. 15 starting the operation.

Any suitable apparatus for continumisl drawing the sheet of glass may be employed, that herein shown consisting of an endless carrier 72, coacting with grip-bars 73, sup- 2o ported on endless chains 74, which elements act not only to continuously draw the sheet of glass, but to advance it through the heating-chamber 46 and into the leer 68. As these last-described elements form no mater25 rial or essential part of the present invention they need not be more ful y described. As here shown, they are. substantially those shown in the previous applications above mentioned. x ,0

For the purpose of enabling the bait 71 to be passed from the rear end of the drawingchamber 46between the carrier and the "gripliars overthe bending-roller and down into the meltiin chamberor pot between the rollers 5 5 and the shields 35 it is necessary that means should be provided for temporarily raising the grip-bars out of contact with the carrier. Such means are clearly shown in Fig. 3, in which 75 75 are the shafts which carrv the sprocket-wheels over which the chains'bearing the grip-bars pass and by which said chains are driven. These shafts 75 rest in bearing-boxes 76 on the exterior of the drawing-chamber, which boxes are suported on substantially horizontal rods 77,

l iaving one end pivoted to the framework of the machine "at 78 and having the other end pivoted at- 79 to spring-links 80, carried on crank-aims- ?81, keyed to shafts 82, to which latter shafts are keyed worm-wheels 83, engaged by worms 84 on shaft 85', to which is keyed a hand-wheel 86..

By turning hand-wheel 86 the operator may revolve the crank-shafts 82, and thereby elevate the links 80, and with them the shafts 75, thus lifting the grip-bars free from the carrier, and the closure 69 being removed bait 71 may be passed downward into the leer and forward through the heating-chain ber 46, over the bending-roller 45, and down into the working chamber 2 between the shields 35 35, and the drum carryin the chains .70 being set in motion by suitable power, as by the sprocket-chain 87, Fig. 5,

eading to the source of power, the bait is drawn u ward over the bending roller through t e heatingchamber 46 between the carrier 72 and the grip-bars 73 and out ofthe rear end of theheating-chamber, where itis detached from the sheet of. glass in any suitable manner, as by cracking the glass from the bait or separating the bait from the chains 70.. At this point the hand-wheel 86 is operated to lower the grip-bars 73 into contact with the sheet of glass, and said sheet being gripped between-the bars and-the carrier and power being applied the sheet of glass is thereafter continuously pulled upward over the bending-roller and advanced by the grip-bars through the leer 68 over the antifrictional bearin ,s' 88.

By inspection of, *ig. 4 it will be seen that each transverse bar of the carrier 72 will travel faster as it passes around the sprocketwheels supporting the carrier than it will during the time when 1t is traveling between the supporting sprocket-wheels, and henceif the bars between the sprocket-Wheels are moving at the same rate of spee as the sheet of glass, as they must, the bars passing around:- the front sprocket-wlieel and coming up into position to receive the glass as it comes from the .ben .ling-roller will be moving. slightly faster than the glass.

o I Now it- 1s essential that the several bars constituting the carrier (during the time when they are in contact with the sheet of glass) should travel at the same rate of speed as the glass, in order that there may be no relative movement between the sheet and the carrier, since such movement would result in a marring of the fire-finish of the sheet. Ihave found that if the bendingroller 45 he placed with its upper surface or highermost point on a level with the u per part of the carrier the bar 72, Fig. 4, o the carrier will come in contact with the sheet of glass at a time when it is moving slightly faster than the sheet, and is therefore liable to, and sometimes does, slightly mar the firefinish of the sheet by reason of the rubbing action that takes place just as the sheet comes in contact with the bar 72. For the purpose of making it impossible for the sheet of glass to contact with the bar 72 until said bar has reached its highermost positionthat is, a position immediately over the drivin shafF-l mount the bend ing-roller 45 in sue a position that the highermost-part of therol er will be above the evel of the carrier, so that thesheet gradually descends from the top ofthe roller onto the carrier, as clearly shown in Fi 4. By this meansI insure the contact of the sheet of glass and the carrier at the time, and only at the time, when said carrier and sheet are moving at the same rate of speed.

As shown in all the figures except Fig. 2, the refractory rollers move in the direction indicated by the arrows in Fig. 1that is, with their adjacent surfaces moving upward and then outward. This is the "preferred direction of movement; but it is not essential,

' since in some cases the rollers 5 5 may move in the reverse direction-that is, with their adjacent surfaces :no ving downward and out ward, as indicated by the arrows in Fig. 2.

It will beunders'tood that all the shafts of the rollers 5 5, the bending-roller 45, the shafts sup orting the carrier, and ip-bars are ma 0 hollow and are oonnected by suitable stuffing-boxes with conduits, which conduct a suitable cooling fiuid, as water, into the hollowpipes, suitable eduction or exit pipaes being provided on the o posite ends. this means injury to the s afts of the several parts by the intense heat of the machine is avoide While for the purpose of convenience in illustration I have shown the rollers 5 5, the friction-clutch mechanism for the bendingroller 45, and the worm-shaft 90 for driving the; mechanism in the drawing chamber as all having power directly from the shaft 19, it

will be readily understood that I may and sometimesido interpose variable speed mechanism between'said"shaft19 and rollers 5 5 and the friction-clutch mechanism for the bowling-roller, to the end that the spee'dof these. elements may be adjusted to se-ure the best results Of course it is entirely possible to so proportion the parts to the shaft 19 as shown in Fig. 3 but in many instances the introduction of variable-speed mechanism is preferable.

It will be seen from the foregoing that I have provided an exceedingly simple method and apparatus whereby a continuous sheet of glass may be drawn from a mass of molten glass, the width of the sheet maintained substantially uniform, and the appearance on the surfaces of the drawn sheet of ribs or strise avoided, as well as any marring effects of the fire-finish due to a rubbing action of the several parts upon the. surface of the glass. i

It wiil of course be understood that parts of the described mechanism. may be employed without other parts and that thereore my invention is not limited to the use of all the parts described and operating as a whole. Moreover, it will be readily comprehended by those familiar with this art that many changes in the form, location, and relative arrangement of the various elcnients described may be made without departurefrom the spirit of mv invention.

Having thus described my invention, what I claim. is-

1. The method of drawing sheet-glass which consists in reparing a mass of molten glass,'drawing a s eet of glass therefrom and simultaneously imparting movement to a part of the surface of the molten glass in opposite directions and away from the two aces. of the sheet.

2. The method of drawing sheet-glass which consists in preparing a mass of molten glass, drawin a sheet of glass therefrom and simultaneousy imparting movement to a art ofthe surface of the molten glass away from each face and also away from each edge of the sheet. v

3. The method of drawing sheet-glass which consists in continuously drawing a sheet of glass from a mass of molten glass, and continuously moving a portion of the surface of the molten mass away from the two faces of the sheet as drawn.

4. The method of drawing sheet-glass, which. consists in; continuously drawing a sheet of glass from a mass of molten glass, and continuously moving a portion of the surface of the molten mass away from the two faces and. the two edges of the sheet as drawn.

5. The method of drawingsheet-glass, which consists in continuously drawing. a sheet of glass from a mass of molten glass, continuously replenishing the supply of molten glass as the drawing proceeds, and continuously moving a portion of the surface of the molten mass away from the two faces and the two edges of the sheet as drawn.

6. The method of drawing sheet-glass,

.which consists inpreparing a mass of molten which consists in drawing a sheet of glass from a mass of molten glass, and continuously submerging the surface portion of the molten mass on each side ofthe sheet being drawn. I

7. The method of drawing .sheet glass which consists in preparing a mass of mol 1' en glass, superheating a portlonof the surface of said molten mass, shielding a portion of said surface from said superheating effect, 7 drawing a sheet of glass from said shielded portion and simultaneouslycausing a part of the same shielded surface to move in 0 p0- site directions and away from the faces of the sheet being drawn.

8. The method of drawing sheet-glass which consists in preparing a mass of molten glass, superheating a portion of the surface of said mass, shielding a portion of said surface from'said superheating effect, drawing a 8 sheet of glass from said shielded portion, causing the surface to move outward or in a direction away from the center toward the edges of the sheet, and simultaneously causing part of the surface of the molten mass oposite the faces of the sheet to move away rom said faces. I

9. The method of drawing sheet-glass glass, heating a P01131311 of the surface above the point which it should have for drawin into sheet form, separating a portion of sai surface and subjecting it to the action of the atinos here whereby its temperature is low ered, rawing a sheet of glass from said sep- 1 arated portion, and imparting movement to part of the surface of said separated portion away from the faces of the sheet.

10. The method of drawing sheet-glass which consists in preparing a mass of molten r glass, superheating a portion of the surface thereof, subjecting another portion of the surface of said molten mass to the cooling action of the atmosphere, drawing a sheet of glass from said last-named portion, moving a 1 part of said cooled surface away from the aces of the sheet being drawn and returning it to said superheated area.

1]. The method of drawing sheetglass which. consists in preparing glass, superheatin two parts of the area of the surface of sai .mass, slowly submerging and advancing said superheated portions to sin-intermediate area ex osed to the cooling influence of the atmosphere and drawing a 1 sheet of glass from said intermediate area.

12. The method of drawing" sheet-glass which consists in preparing a mass of molten glass, superheating two parts of the areaof the surface of said mass, slowly submerging 12 and advancing said superheated portions to an intermediate area exposed to the cooling influence of the atmosphere, drawing a sheet of lass from said intermediate area and s1- niu taneously moving parts of the surface of i 0 a mass of molten 1 r 5 said intermediate area away from the faces of the sheet being drawn and returning them to said superheated areas.

13. In a machine for drawing sheet-glass, the combination of a receptacle containing molten glass,vmeans for drawing a sheet of glass therefrom, and means simultaneously imparting movementlto parts of the surface portion of themolten mass away from the two faces of the sheet as it is drawn. 7

14. In a machine for drawing sheet-glass, the combination of a receptacle containin molten glass, means for'drawing a sheet 0 glass therefrom, andameans simultaneously imparting movement to parts of the surface ortion of the molten mass away from each ace and each edge of the sheet as it is drawn.

15. In a machine for drawing sheet-glass,

the combination of a receptacle containing:

molten glass, two parallel rollers revoluble in opposite directions with the lower partoi their peripheries immersed in the molten lass, and means for drawing a sheet of glass 'orn the molten mass between said rollers.

16,. In a machine for drawing sheet-glass,

N the combination of a receptacle containing molten glass, two parallel rollers revoluble in opposite directions with their adjacent surfaces moving upward and the lower part of their. peripheries immersed in the molten glass, whereby a portion of the mass of mo'l ten glass is carried over and outward by said rollers, means for revolvin' both'of said'rollers at the same speed, an meansa for draw ing a sheet of lass from the mass of glass between said rol ers.

17WIn a machine for drawing sheet-glass, the combination of a receptacle-containing molten glass, two parallel rollersrevoluble in opposite directions with their adjacent-sun faces moving upward and the lower part of their peripheries immersed in the molten glass, means for revolving said rollers, means or adjusting the rollers toward and from each other, and means for drawing a sheet of glass from the molten mass between said rollers.

18. In a machine for drawing sheet-glass,

the combination of a receptacle containing molten glass; two parallel revolving rollers with their adjacent surfaces moving upward and the lower partof their peripheries immersed in the molten glass, means supplying heat to the rear sides of said rollers, and means drawing a sheet of lass from the molten mass between said rol crs.

1'9. In a machine for drawing sheet-glass,

the combination of a receptacle containing molten glass, two parallel revolving rollers with their adjacent surfaces moving upward and the lower part of their peripheries immersed in the molten glass, means drawinga sheet of glass from the molten mass between.

.said rollers, means supplying heat to the rear eseeae sides of the rollers, and means protecting the sheet from said heat.

20. In a machine for drawing sheet-glass, the combination of a receptacle containing molten glass, two parallel revolving rollers with the lower part of their peripheries immersed in the molten glass, means for vertically and horizontally adjusting said rollers, and means for drawing a sheet of glass from the molten mass between'said' rollers.

mass of molten glass, means for drawingv a sheet of glass of uniform width therefrom,a

roller over which said sheet-is bent as drawn,

and power devices tending to but fallin short of revolving said roller, the friction'a contact of the sheet with the roller supplying the additional power necessary to revolve the roller.

22. In a machine for drawingsheet-glass, the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of glass of uniform widththerefrom, and a bending-roller driven by theilombined action of power devices and the friction of said sheet as it is bent over said roller;

23. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of glass of uniform width therefrom, a roller over which said sheet is bent as drawn, power devices tending to revolve said roller, and a slip connection betweensaid devices and roller. i 24. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of glass of uniformwidth. therefr on1,a roller over which. said sheet is bent as drawn, power connections tending to revolvesaid roller, and a'friction-clutch interposed in said connections.

25. In a machine for drawing sheet glass,

the combination of a receptacle containinga f mass of molten glass, means for drawing a sheet of uniform width therefrom, a' roller over which said sheet is bent as drawn, a lever device attached to the shaft of said roller, power devicestending to revolve said roller, and yieldin ,"connections between said power devices am said roller;

'26; In a machinefon drawing sheet-glass,

the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of uniform wldth therefrom, a roller over which said sheet is bent as, lrawn, a

hand-wheel attached to theshaft of said roller, power devices tending to revolvesaid roller, and yielding connections between said power devices and saidroller. 2711x1 0; machine for drawing sheet-glass,

the combination-of a receptacle containing a mass of molten glass, means for drawing: a

mass of molten glass, two parallel rollers resheet of glass of uniform width therefrom, power devices, and a roller over which said sheet is bent as drawn and receiving driving power from the sheet and from said power devices.

28. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of glass therefrom, means imparting movement to parts of the surface portion of the molten'mass away from each face of the sheet as it is drawn, and a roller over which said sheet is bent as drawn and receiving drivin power from the sheet.

29. n a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of glass therefrom, means imparting movement to parts of the surface ortion of the molten mass away from each dice of the sheet as it is drawn, power devices, and a roller over which said sheet is bent as drawn and receiving driving power from said sheet and from said power devices.

30. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, two parallel rollers having a portion of their peripheries immersed in said molten mass, means for drawing a sheet of glass from the molten mass between said rollers, and 'a roller over which said sheet is bent as drawn and receiving driving power from said sheet.

31. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, means for drawing a sheet of glass of uniform width therefrom, a roller over which said sheet is bent as drawn, and a sheet-receiving carrier moving in a plane below the top line of said roller.

32.' In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten glass, means for continuous! drawing a sheet of glass of uniform widt therefrom, a roller over which said sheet is bent as drawn, and a continuously-moving sheet-receivin carrier in a plane below the top line of said roller.

33.- In a machine for drawing sheet-glass, the combination of a receptacle containing a volving in opposite directions with a ortion of their peripheries immersed in sai mass, means for drawin a sheet of glass from the mass between sai rollers, means directing a high heat against the rear sides of said rollers, and means shielding the sheet of glass from said heat.

34. In a machine for drawing sheet-glass,

the combination of a receptacle containing a mass of molt n glass, two parallel rollers revolving in opposite directions with their peripheries immersed in said mass, means for drawing a sheet of glass from the mass between said rollers, means conducting hot products of combustion a ainst the rear sides of said rollers, means to t e rearof said rollers conduct-ing said products to a suitable .means directing a cooling fluid through the shafts of said rollers, and means drawing a sheet of glass from said molten mass.

36. In a machine for drawin sheet-glass, the combination of a receptac e for molten glass, two parallel rollers mounted with the ower part of their peripheries in the molten glass, means for drawing a sheet of glass of uniform width from the molten glass between said rollers, two hollow shields mounted above said molten glass, one between each roller and the sheet being drawn, and means for circulating a cooling medium through said shields.

37. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten lass, means for drawing a, sheet of glass 0 uniform width from said glass, two rollers mounted one on each side of the said sheet with their eripheries dipping in said molten glass and t eirshafts ro ecting outward through the walls of said receptacle, and means su plying a high-temperature in said receptacie adjacent to-the ends of said rollers,

38. In a machine for drawing sheet-glass, the combination of a receptacle containing a mass of molten lass, means drawing a sheet of uniform width from said mass, two rollers mounted on hollow shafts and with their peripheries dipping into said molten mass on each side of said sheet, means directing a cooling medium through said shafts, and burners directing a jet of flame into said rece tacle adjacent to the ends of, said rollers.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

- IRVING W. COLBURN. Witnesses:-

E. WASHBURN, RICHARD ZINKERNAZEL.