US1641920A - Sheet-glass apparatus - Google Patents

Description

H. F. CLARK SHEET any; APPARATUS Sept. 6 1927.

Filed Sept. 11 1926 Patented Sept. 6, 1927.

UNITED STATE-Sf PATENT, OFFICE.

HENRY r. CLARK, or BELLE VERNON, rnNNsYLvANra, assr'eNon r wiNnow'. GLASS, mcnINn couramnor rrrrsnuaen, rnNNsnvn m, a CORPORATION or NEW JERSEY.

Application filed September 11,1926. SerialNo. 184,798.

This'invention relates to sheet glass apparatus, and particularly to an improved form of drawing mechanism fora raising a sheet of glass as it is drawn from a bath.

6 In the Fourcault rocess of drawing sheet glass, the glass is raw-n upwardly from a slotted clay block which is partly submerged in a' bath of glass. It continues in its up-- ward travel for a distance of some thirty 10 feet at which time it is cooled sufliciently to permit of its being cut into sheets. Various lifting devices have been proposed, but the mechanism generally employed consists of a number of pairs of traction rolls.

-. As heretofore constructed, each .pair of rolls has been comprised of one fixed roll and one yieldable roll. The yieldable roll has generally been carried on bell cranks a weighted arm which urges the havin yielda 1eroll towards the fixed roll, thus providin suflicient pressure on a r1s1ng sheet of glass etween the rolls to insure its upward travel.

The apparatus just described has been used for many years and while in some respects it is satisfactory, it falls far short of the ideal lifting mechanism because it does not take care of a very common situation which arises insheet glass drawing.

No matter how carefully the melting step is carried on, stones of various'sizes will be found in molten glass. These stones move toward the point of draw and are picked up inthe rising sheet.- If the stone happens to project from the plane of the sheet on that side where. the movable roll is rovided, no harm results, for the roll simp y moves outwardly until the stone has passed. It will be understood that a large number of pairs of rollsare rovided and that as a stone moves upwar y, each pair of rolls is tem whi e"the other. rolls continue to draw the glass upwardly.

Assume, however, that the stone projects from the other side of the glass sheet. The

rolls on this side cannot yield and the glass,

sheet is therefore deflectedaway from the fixed roll a distance depending upon the amount the stone rejects outwardly from the normal plane 0 the sheet surface. The

sheet is, of course, engaged by rolls above 1 rarily ineffective for a short period,-

and below the fixed roll encountered by the stone and the yieldable rolls in these pairs resist the sldewise displacement of the sheet. In consequence, it is subjected to a severe befiding action and breakage frequently resu s.

I provide a drawing apparatus comprisi'n airs of traction rolls, each roll in a pail ein' movable away fromthe sheet. I pref.-

erab y employ counterweights for urging the rollain a pair towards one another and in addition to thesewei hts, I also employ means for urging the ro toward a normal central positionin the plane of the rising sheet. Unless some such means-is provided there 1s the. danger that the rolls may tend to occupy a position considerably to one side of the plane of the sheet.

In the accompanying drawing which illus trates more or less diagrammatically a preferred form of the invention and certain modifications thereof, T

Figure 1 isla'side elevation partly broken away of a drawing tower embodying the invention Figure 2 is a side'elevation of a portion of a tower showing a modified form of the inventlon;

e 3 is a section taken on the line III-III of Figure 2;

Figure 4 is a view corresponding to Figure 2, but showing, a still further modification; and

a Figure 5 is a view illustrating a modified form of counter weight arm whereby the SpIlllg means may be eliminated.

Referring first to Figure 1, there is shown a drawing tower indicated generally by' the reference character 2 and provided with heat baflies 3 of usual construction. A sheet of glass G'is shown as rising in the tower and engaged by traction rolls 4; arranged in pairs. i

The rolls are driven from a vertically extending power shaft 5 connected through mitre gears 6 to horizontal stub shafts 7 Each stub shaft. 7 is connected through a spring coupling to a worm shaft 9.having right and left hand worms 10 thereon. The

worms-10 engage worm wheels 11 which are.

carried to the shafts of the draft or traction rollers."

The draft rollers are mounted on the vertically extending arms 12 of hell cranks pivoted on the wall of the draft tower at 13.

Eli

The bell cranks each have a substantially horizontal arm 14 provided with an adjustable counter weight 15 for urging the draft rollers in each pair towards one another. It will be noted that the rollers lie between their points of pivotal movement 13 and the worms 10, thus insuring that the force a plied through the gearing will urge the re ers towards the glass instead of away from it.

With the apparatus just described, it makes no difference whether a stone projects from either side of the rising sheet G, or from both sides thereof. The rollers are free to yield independently of one another. If a roller is forced away from the sheet, its worm wheel 11 simply rolls along the worm 10 and the drive is uninterrupted, so that when the roll returns to its normal position, it immediately takes up its load.

Obviously each pair of rolls, as so far described, must be maintained in a state of nice balance if all the pairs of rolls are to occupysuch a position that the sheet will not be deflected as it passes between them. It is desirable to provide means which will prevent pairs of rolls from being displaced sidewise from the pllane of the rising sheet. For this purpose, employ casings 16on the sides of the housing, each casing having a plunger 17 therein behind which is a compression spring 18. The plungers 17 bear a ainst the arms 14 and the springs 18 are placed under an initial compression. Obviously, if the rolls in a pair tend to move away from the central position, a spring on one side of a pair of rolls will be compressed while the spring on the other side will be decompressed to a certain extent, thus settin up an unbalanced force which will tend to ring the rolls back to central position.

In Figure 5 there is illustrated a modified structure for accomplishin the same result. In this form of the inventlon, the arms 14", instead of being horizontal, are inclined downwardly at a rather steep angle. The weights 15 have an effective arm 7", and with the arms inclined as shown in Figure 5, this effective distance varies rapidly upon even a slight movement of the rollers. They will, therefore tend to maintain a position wherein the effective moments set up by the weights 15- are in balance.

Figures 2 and 3 show a modified structure wherein the rollers in a pair are connected by spur gears 19. Instead of the rollers be ing journaled in hell crank arms, they are mounted in bearing blocks 20 movable on guides 21 secured to the side of the housing. Weighted bell crank arms 22 are provided, and these bear against the backs of the hearing blocks 20. A pinion 23 is mounted on a enten stub shaft 24 and is connected to one of a pair of mitre gears 25. The other mitre gear ,is keyed to a vertically extending drive shaft 26 from which each pair of rolls is driven.

It will be noted that the guides 21 are inclined. As is well known, a pair of spur gears having their teeth out according to the involute system will maintain their speed ratio regardless of the center-to-center distance. During the actual period of movement of the gears towards or away from one another, there will be a supplemental angular movement of the driven gear relative to the driving gear, due to the fact that the teeth vary in width. This condition obtains if the gears are moved towards or away from one another along their common center line. I have shown the guides 21 as being placed at an angle to the common center line of the gears which corresponds to the angle made by the common normal of the gear teeth with such common center line. This minimizes 0r eliminates the supplemental angular movement of the rolls and, therefore, eliminates a factor which might cause irregular traction and therefore breakage of the sheet.

In Figure 4 there is shown a still further modification wherein the rollers are mounted on the arms 27 of hell cranks pivoted at 28. The bell cranks have weighted arms 29 and are provided with the spring centering means described in connection with Figure 1.

A drive pinion 30 is mounted on a stub shaft 31 and meshes with a gear 32 on one of the pivot shafts 28. The gear 32 meshes with a companion gear 33 and the gears 32 and 33 each mesh with pinons 34 on the roll shafts.

1 have illustrated and described a preferred embodiment of the invention, but it will be understood that it is not to be limited, since it ma be otherwise embodied within the scope or the following claims.

I claim 1- 1. Sheet glass apparatus, comprising a traction roll movable toward and away from a glass sheet, and means for supplying an increasing resistance to movement of the roll as it moves toward the glass sheet.

2. Sheet glass apparatus, comprising a pair of traction rolls adapted to engage a glass sheet between them, each roll in the pair being movable away from the sheet, and means supplying an increasing resistance to movement of each roll as it moves toward the glass sheet.

3. Sheet glass apparatus, comprising a traction roll adapted to engage a glass sheet,

, means urging the roll towar the sheet, and

v and ieldable means associated with each roll or causing them to normally occupy a position immediately alongside the normal plane of-travel of the glass sheet.

5. Sheet glass apparatus, comprising a pair of traction rolls, each roll in the pair being movable toward or away from the sheet, and yieldable means associated with each roll for causing them to nor'mally occupy a position immediately alongside the normal" plane of travel of the glass sheet, said yieldable means supplying an increasing resistance to one roll and a decreasing neously move away from such posltion.

6. Sheet glass apparatus, comprising a pair of intergeared traction rolls, each roll in the pair being movable toward and away from the sheet, and means for guiding the rolls in such movement, said means being eflective for minimizing supplemental relative angular movement of the rolls during their movement.

- In testimony whereof I have hereunto set,-

myhand.

HENRY F. CLARK.

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