US2881565A - Tempering of sheet material - Google Patents

Description

April 14, 1959 G. WHITE 2,881,565

TEMPERING 0F SHEET :MATERIAL Filed June 14, 1955 3 Sheets-Sheet 1 1 INVENTOR. y BY fimfld 3M6 em e A TTORNEYS April 14, 1959 G. WHITE 2,881,565

' TEMPERING 0F SHEET MATERIAL Filed June 14, 1955 v 3 Sheets-Sheet 2 5&4

1'- J .5 INVENTOR.

B z066egdtd0/1e A TTORNEYS April 14,- 1959 G. WHITE 2,881,565

TEMPERlNG OF SHEET MATERIAL Filed June 14, 1955 5 Sheets-Sheet 3 I I]! H II IN V EN TQR. 2 5M444 /Me ATTORNEYS United States Patent TEMPERING F SHEET MATERIAL Gerald White, Rossford, (lhio, assignor to Libbey-Owens- Ford Glass Company, Toledo, Ohio, a corporation of Application June 14, 1955, Serial No. 515,275

6 Claims. (Cl. 49-45) The present invention relates broadly to'the tempering of sheet material and more particularly to an improved method and apparatus for tempering glass sheets on plates.

It is common practice in the tempering of glass sheets to first heat the sheets to substantially the point of softening of the glass and then to suddenly chill the heated sheets to place the outer surfaces thereof under compression and the interiors thereof under tension. By this means, the mechanical and heat resistance characteristics of the sheets may be changed.

The method and apparatus of the invention may be used to treat various types of flat or curved sheet material and in the production of electrically conductive films on glass articles as described in Patent 2,429,420 to H. A. McMaster, issued October 21, 1947. However, it will be described primarily with relation to the tempering'of bent or curved glass sheets and has as its primary object the provision of a novel method and apparatus for evenly tempering bent glass sheets or the like.

Another object of the invention is to provide means of obtaining a more efficient use of the tempering cooling medium so as to impart greater tempered strength to thin glass sheets than has heretofore been possible by previous methods.

A still further object of the invention is to arrange the nozzles through which the cooling medium passes to the sheets so as to conform as nearly as possible to the shape of the sheets.

A still further object of the invention is to provide a novel means of directing the cooling medium or fluid from the nozzles along a path substantially parallel with v the direction of movement of the sheets.

Other objects and advantages of the invention will become more apparent during the course of the follow ing description when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals areemployed to designate like parts throughout the same:

Fig. 1 is a plan view of the equipment for carrying out the invention showing the general arrangement of various components thereof;

Fig. 2 is a side elevation of the tempering apparatus of the invention;

Fig. 3 is a front elevation of the entrance end of the tempering apparatus shown in Fig. 2;

Fig. 4 is a sectional view taken substantially along lines 4-4 of Fig. 2 showing a bending mold passing through the tempering apparatus;

Fig. 5 is a fragmentary detail view of a typical nozzle of the invention;

Fig. 6 is a plan view of the tempering apparatus of the invention including a fragmentary section of the central manifold;

Fig. 7 is a fragmentary perspective view of a portion of the nozzles-of the invention; and v Fig. 8 is a schematic showing of a flow-pattern of the 2,881,565 Patented Apr. 14, 1959 ice cooling medium flowing through the nozzles of the invention.

With reference now to the drawings and particularly to Figs. 1 and 2, molds of the type indicated generally at 10 in Fig. 4 carrying glass sheets S to be bent and tempered are started along a power conveyor section 11 which extends through a furnace or heating chamber 12 and carries the molds into the inlet end 12 thereof. At the discharge end 13 of the furnace 12 the molds are carried on narrow chain conveyors 14 and 15 which pass along the sides of a quenching or tempering station 16 and permit the mold to straddle a lower portion of the quenching system.

From the chain conveyors 14 and 15 the molds are transferred to another conveyor section 17 leading to a semi-circular conveyor section 18 which reverses the direction of travel of the molds and leads them to a return conveyor 19 extending alongside the heating chamber 12 and terminating at an unloading station 20. The bent glass sheets, which have now cooled to a temperature at which they may be handled, are removed from the molds at the unloading station 20 and the molds are then carried on a semi-circular conveyor 21 to a loading station at the start of the conveyor 11.

Referring now particularly to the quenching or tempering system 16, this system includes a lower blast-head 22 (Fig. 3) and an upper blast-head 23 through which a suitable cooling medium such as air may be directed to the sheets as they pass thereby. More particularly, the upper blast-head 23 is mounted above the path of the sheets on a frame structure which includes uprights 24 and cross beams 25, while the lower blast-head is supported on suitable I-beams 26 (Fig. 4) below the path of the sheets.

Dealing now specifically with the lower blast-head 2 as may best be seen in Figs. 2, 3 and 4, it includes a plurality of transversely extending lower manifolds or headers 27 supported on and between the I-beams 26. Extending upwardly and between the central portions of the manifolds 27 are a plurality of longitudinally extending central nozzles 28 preferably arranged to follow the general central contour of the bent sheet S on the mold 10.

Each of the nozzles comprises a bottom wall 29 (Fig.- 5), side walls 30 having converging side portions 31 and transverse end walls 32. The converging side wall portions 30 define a longitudinal slot or orifice 33 (Fig. 7) therebetween at the extreme ends of the nozzles through which the cooling medium may pass and be directed to the lower surface of the sheets passing thereby. Cooling medium may be supplied to the respective nozzles through suitable openings 33' formed in the bottom walls 29 of the nozzles which mate with corresponding opening in the respective manifolds. This cooling medium may be brought to the manifolds by pipes or conduits 34 connected to a suitable source not shown.

Secured to and extending upwardly between the respective lower manifolds and along the outer edges thereof are ducts indicated generally at 35 (Fig. 4) which at their upper ends carry a plurality of angularly disposed longitudinally extending nozzles 36 adapted to direct the cooling fluid to the extreme curved ends of the bent glass sheet S on the mold 10. These nozzles 36 are similar in construction to the lower central nozzles 28 and may be oriented to conform to the general contour of the bent end portions of the sheet so as to direct the cooling medium substantially-evenly over the lower surface thereof. The cooling medium is supplied to the ducts through suitable openings provided in each of th respective lower manifolds 27. Y Turning now to the upper blast-head 23, it is formed in a manner'substantially similar to the lower blast-head 22 and includes transversely extending manifolds or headers 37 mounted on the frame cross beam 25. Centrally disposed nozzles 38 extend'between the respective manifolds in a direction substantially parallel to the direction of movement of the sheets and are connected to the upper manifolds 37 through slots or openings 39 as shown in Fig. 6. The upper central nozzles, similar in design to nozzles 28 and 36, are convex downwardly to substantially conform to the central curvature of the mold and bent sheet S and may be staggered with relation to the lower central nozzles 28 to give a more uniform quenching pattern. In order to adequately cool the upper curved end portions of the sheet S there are provided enlarged end nozzles 40 having three angularly disposed nozzle tips 41 disposed to substantially conform to the end curvature of the sheets.

From the above, and with particular reference to Fig. 4, it will be apparent that the upper nozzles 38 and are disposed downwardly along a convex pattern. while the ends of the lower nozzles 28 and 36 form a downwardly concave pattern so that a clear space is left between the nozzles which conforms generally to the curvature of a bent glass sheet S and the mold 10. The nozzles may in this way be placed substantially equidistantly from the surfaces of the glass sheet thus making it possible for the cooling medium to be directed evenly and at substantially the same pressure along all areas of the bent sheets. However, the angular disposition of the nozzles may be changed to.conform to curvatures of various shapes.

If desired, the cooling medium or fluid which emerges from the nozzle orifices in longitudinally extending strips or layers at substantial right angles to the sheet surface may be controlled by the use of directional fins or plates 42 (Fig. 7). These fins 42 may be formed of bendable metal and according to the preferred embodiment shown in'Fig. 7, may be alternately staggered on one side and then the other of the longitudinally extending orifices 33.

More particularly, as shown in Fig. 7, the directional fins 42 on one side of an orifice 33, indicated by the numeral 43, may comprise angularly disposed tabs a, b and 0, while the directional fins on the other side of the orifice indicated by the numeral 44 may be spaced longitudinally from the fins 43 as at d and comprise angularly disposed tabs e, f, and g. Thus, as the cooling medium emerges from a nozzle orifice 31 it strikes the tabs (1, b, and c and e, f, and g and is deflected in predetermined angularly disposed streams away from its normal path toward a sheet so as to sweep the sheet in a predetermined pattern across its width.

For example, as may be seen in Figs. 7 and 8, the tabs may be bent to progressively deflect the cooling fluid across the sheet. As particularly illustrated in Fig. 8, the cooling fluid striking the tab a of a directional fin 43 will be. deflected to sweep an area a between the projection lines 45and 46; the cooling medium striking tab b will sweep an area b between projection lines 46 and 47; and the medium striking tab c will sweep an area c between projection lines 47 and 48. The space d between the fins 43 allows the cooling medium to flow directly fromvthe orifice 33 at substantially right angles to the passing sheet. However, after leaving the orifice area corresponding to the space d, the cooling fluid diverges and'sweeps the area d between projection lines 48 and 49.

Continuing, tabs e, f, and g of the directional fins 44 deflect the cooling medium in streams to the other side of the areas d as indicated by the areas .2, f, and g between projection lines 49-50, 50-51, and 5152 respectively. As will be apparent from Fig. 8, the quenching pattern of each of the nozzles may overlap one another as is illustrated by the intersections of the projection line 53 from an adjacent nozzle (not shown). In this way, the passing sheet may be swept across its entire width. Of course, each of the areas a, b, c, d, ete., swept by the deflected cooling medium may overlap one 4 another both transversely and longitudinally of the disposition of the nozzle orifice because of the divergence of the cooling medium; this effect further aids in evenly cooling the sheet.

As will be apparent from Fig. 8, the staggered relation of the lower nozzles 28 with respect to the upper nozzles 38 enables cooling medium to be directed to the sheet in a further overlapping relation as indicated by projec tion lines 53 and 53". In other words, where there is a space between the upper nozzles 38, a lower nozzle 28 will be directing the cooling fluid toward the area from the underside of the sheet. Because of the relative thinness of the sheet, the cooling medium directed at one side of the sheet will have a decided cooling effect through the entire thickness of the sheet and thus a constant uniform cooling effect over the sheet is obtained. Of course, the tempering pattern can be further finely controlled and adjusted by arranging the location of the directional fins and the angular relationship of the respective tabs.

After the cooling medium strikes a passing sheet, it may be exhausted through openings or spaces 54 provided between the respective nozzles and the manifolds (Figs. 4 and 6). By providing a means of quickly exhausting or removing the hot expanded cooling medium after it has been deflected from the hot sheets, a better tempering and quenching pattern is obtained over the sheets and less initial pressure is required since back pressures which tend to build up along the path of the sheets are reduced enabling the cooling medium to strike the sheet directly and to pierce the film of hot cooling medium adjacent the surface of the sheets.

To further facilitate the removal of the hot cooling medium after it strikes a passing sheet, the lower central nozzles 28 have their horizontal bottom walls 29 extending upwardly as at 55 (Fig. 2) so as to offer less resistance to the exhaust flow. Likewise, the ducts 35 which mount the lower side nozzles 36 are walls recessed upwardly as at 56 to aid in exhausting the hot cooling medium. For the same purpose, the upper walls 29 of the upper nozzles 38 extend downwardly as indicated by the dotted lines 57 in Fig. 2.

To protect the glass sheets from uneven cooling and to decrease the heat loss from the furnace, the exit opening 13 of the furnace is provided with partially closed baflie plates 58 and 59 (Fig. 2) which are spaced from one another along a contour that conforms to the end elevation of the mold and the glass carried thereon. To further aid in restricting the flow of hot gases toward the entry end of thequenching station 16, there are provided deflecting or baffle seats. More particularly, as shown in Fig. 3, the lower central nozzles 28 are provided with an angularly disposed baflie plate 60, while the side nozzles 36 are provided with bafie plates 61, and the upper nozzles 38 and 41 are provided with a battle plate 62.

Now, in moving through the tempering station 16 in the direction indicated by arrow x, the molds and the glass sheets S are carried by the conveyors 14 and 15, each of which includes a conveyor chain 63 (Fig. 4) driven by a sprocket 64 mounted on a short cross shaft 65. The cross shaft 65 at its outer end. is connected to a suitable drive sprocket arrangement indicated generally at 66 which in turn is connected to transverse power shaft 67 journaled in bearings 68. This particular drive means is more fully described in U'.S. Patent 2,646,647 to W. P. Bamford et al. and may be utilized to rapidly move the molds 10 from the furnace and into the quenching station, after which, the conveyor speed may be reduced to slowly move the molds through the tempering region.

The conveyor chains 63 of conveyors 14 and 15 during travel along their upper flight ride on longitudinal wear plates 69 supported on channel irons 70 secured between side channel irons 71 and 72 which together with a base plate 73 form a box-like frame for the conveyor chain.

The return or lower flight of the conveyor chains 63 run on the base plate 73. Inv this arrangement the upper portion of the side channel irons 71 and 72 serve as side guards to prevent the molds from departing from their intended path.

Reviewing now the entire process of the invention bent glass sheets S carried by the molds 10, which may be of a special hinge type so as to enable them to ride between the respective nozzles as shown in Fig. 4, and are moved along the conveyor section 11 and pass through the heating furnace or chamber 12, after which, they are transferred onto conveyor sections 14 and 15 and moved through the tempering station 16. During passage through the tempering station 16 the sheets may be quenched or cooled generally across their entire width by means of the cooling medium flowing through the longitudinally extending nozzles which may be directed in a predetermined path by the directional fins or plates 43. These fins, as may clearly be seen from the schematic diagram of Fig. 8, progressively deflect portions of the cooling medium, which emerges from the nozzles in strips or layers substantially parallel to the direction of movement of the sheets stepwise away from its normal path so as to sweep the width of the sheet.

After emerging from the quenching or tempering station 16, the molds are transferred to the conveyor section 17 and moved to the unloading station 20 whereupon the tempered sheets are removed and then moved to the loading station of the conveyor 11 where they will be in position to begin another bending and tempering cycle.

While one method of tempering and quenching sheet material has been shown, it will be evident that the cooling medium may be regulated by controlling the size of the orifices or by changing the angular position of the fins or their number and/or position along the length of the nozzles. Moreover, while the sheets have been shown to move while the nozzles remain stationary, it will also be evident that the nozzles may be moved relative to the sheets, or both the sheets and the nozzles may be moved relative to one another. Also, of course, other means of carrying the sheets may be employed.

It will of course be understood that the invention disclosed herein is to be taken as the preferred embodiment thereof and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or scope of the following claims.

I claim:

1. A method of tempering glass sheets or plates by first heating the sheets and then rapidly chilling the surfaces thereof, comprising directing a cooling fluid toward said sheet in the form of a layer, progressively deflecting portions of said layer stepwise at different angles to one side of the normal path of said layer toward said sheet while progressively deflecting alternate portions of said layer stepwise at different angles to the opposite side of said normal path, and effecting relative movement between said sheet and said cooling fluid to cause a surface of said sheet to be contacted by said fluid.

2. The method of tempering glass sheets or plates as claimed in claim 1, in which the layer of cooling medium is disposed substantially parallel to the direction of relative movement between the sheet and said layer.

3. In apparatus for tempering bent glass sheets, in combination, conveyor means for carrying molds bearing bent glass sheets thereon along a definite path, a plurality of elongated spaced nozzles disposed toward the path of the molds and bent glass sheets, said nozzles having long narrow slots therein disposed substantially parallel to the path of movement of said sheet through which a cooling medium may pass, and means adjacent said slots in said nozzles to progressively deflect portions of said cooling medium stepwise at angles of varying magnitude transversely of the path of said sheets.

4. Apparatus for tempering sheets or plates, comprising a support for holding a sheet to be tempered, means for directing a fluid cooling medium onto a surface of said sheet including a slot through which cooling medium may pass, means for bringing cooling medium to said slot, means for creating relative movement between said sheet and said slot, said slot being disposed substantially parallel to the direction of movement between the slot and sheet, and a plurality of deflection fins having tabs thereon which are angularly disposed with respect to one another mounted adjacent said slot for progressively deflecting the cooling medium stepwise at angles of varying magnitude after it passes through said slot from its normal path toward said sheet.

5. Apparatus for tempering sheets or plates as claimed in claim 4, in which said deflection fins are disposed to deflect the cooling medium to one side and then the other of said slot.

6. Apparatus for tempering sheets or plates as claimed in claim 4, in which there are provided a plurality of spaced slots in said directing means through which the cooling medium may pass.

References Cited in the file of this patent UNITED STATES PATENTS 2,188,401 Crowley Jan. 30, 1940 2,646,647 Bamford et al. July 28, 1953 FOREIGN PATENTS 707,949 Germany July 8, 1941

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