US2372418A - Apparatus for bending glass sheets - Google Patents

Description

March 7, 94 L. JEX-B. FORBES ETAL 2,372,418

APPARATUS FOR BENDING GLASS SHEETS Filed Jan. 23, 1939 3 Sheets-Shegt 1 8 6 9 9 AMI IYIJ mnni|/ a. 7

Z'W/s J51 -BLA/( Fb/PBES Q, 65 0 965 IV/L L IAN Eva-was 31/20 March 27, 1945. L. JEX'B. FORBES EIAL. 2,372,413

APPARATUS FOR BENDING GLASS SHEETS Filed Jan. 23, 1939 L's Sheets-Sheet 2 Sivuvwkws memes Ma. 21, 1945; g

I 2,872,418 4 arraaa'rus ron BENDING cuss snnn'rs Lewis Jex-Blake Forbes, Rainhill, and George William Terence Bird, Prescot, England, assignors to Societc Anonyme des Manufactures des Glaces et Products Chimiques de Saint- Gobain, Chauny & Cirey, Paris, France, a corporation of France Application January 23, 1939, Serial No. 252,464 In Great Britain January 29, 1938 1 Claim. (Cl. 49-67 This invention relates to apparatus for bending glass sheets.

It is customary to bend glass sheets by making a wooden former and bending the'glass over it, the sheet or plate having been previously heated to the softening point or allowed 'to retain its residual heat of formation. The wooden former is either of solid wood or consists of a plurality of spaced battens fixed to a base or to sid members. When a single sheet or only a few sheets have to be bent to a given curvature, the cost of making the former unduly increases the cost of the bent sheets. when a large number of sheets have to be bent,the former gradually loses its correct form by reason of the wood charring away more rapidly at those parts which first come into contact with the glass.

According to the invention, a former is formed of a plurality of slats or elements held side by side in a frame, with guiding means on the frame adapted to permit the elements to slide relatively one to another back and forth in one direction, so that their front'edges, or front surfaces, present substantially acurved surface and means for holding the elements against relative movement when pressed against the glass. .The elements may beheld against relative movement R either by compressing the plurality of elements to lock them by friction or by pressing them against the glass by means of a templet or former pressed against their back edges. These elements may be either slats or reglets (i. e. bars of small cross section), according to the desired shape which is to be given to the surface of the glass sheet treated.v

The slats may be used for the realization of surfaces which can be generated by straight generating lines. When skew surfaces, spherical sur;

faces for example, must be realized with a former according to the invention, one will have to make use of slats or reglets.

Said elements may be made of any appropriate material and preferably wood.

The invention also comprises means for press- I ing together two formers, having elements of.

which the front edges lie on surfaces curved similarly but inversely, while the glass sheet is between them, the pressing means preferably consisting of two frames adapted to slide horizontally in guides and fluid pressure means adapted to press them towards one another while the formers and the glass sheet are interposed.

Figure 2 an enlarged side view looking toward the left end of Figure 1 and represents one form of realization of a bending former according to the invention,

Figure 3 is a perspective view on a smaller scale of a device for giving the former correct shape.

Figure 4 is a perspective view of a former for cooperating with the opposite side of a sheet of glass when the glass is bent by the device of Figure 1.

' Figur 5 is a part side view on a smaller scale of a bending apparatus with the formers shown in Figures 1, 2 and 4 in place, a

Figure 6 is a central vertical section on the line 8-6 of Figure 8,

Figure 7 is a vertical section on the line 1-1 of Figure 9,

Figure 8 is a plan view, reduced in size, of Figure 6.

Figure 9 is an enlarged plan view of Figure 7.

Figure 10 is a plan view showing the combined use of the formers shown in Figures 1 and 4.

Referring to Figures 1 and 2, the former consists of a plurality of wooden slats i, held between two uprights 2 and 2a. Each slat I has two slots 3, through which pass two bolts 4. which pass also through holes in the uprights 2 and 2a. When the nuts in of the bolts 4 are slack, the slats are free to slide between the uprights 2 and 2a, being guided by the bolts 4 in the slots 3. As shown in Figure 1, the slats l are so placed between the uprights 2 and 2a as to present a front (the lower part in Figure 1) which is substantially a cylindrical surface. The templet consisting of one or more templet parts 5. shown in Figure 3 serves to give the front a surface of any desired curvature. Two templet parts 6, having their upper edges 8 curved to the desired curvature, are mounted on a base 1 by brackets I, and end pieces 9 are similarly mounted thereon. The,former of Figure 1 is placed on thetemplet so that the front edges of the uprights 2 and 20. rest' on the end pieces 9, and, with the nuts ll slack, the slats I are shaken or tapped down until all the slats rest on the edges 6 of the two templet parts 5. The bolts iii are then tightened so that the slats I are compressed between the uprights 2 and 2a, and are then held against sliding by friction. The former then is substantially equivalent to a former of solid wood having a front surface of the desired curvature. The curvature can be changed by replacing the templet parts'5 by other templets andagain shaping. the former on them. Further, if the curvature becomes altered by reason of the central slats charring away more rapidly than the outer slats,

the former can be given the correct shape again by the use or the laminar former. This can be accomplished by slacking the nuts I and shaking or taping downthe slats 1 until the operative faces of the slats rest on the edges 6 of the templet parts as above explained.

It has been discovered that a sheet can be bent more accurately to a given curvature if the convex former has a solid or nearly solid surface, but that the concave former can consist of spaced battens without affecting the accuracy of the bend. Thus the convex former of Figure 1 can be used with the concave former of Figure 4. It is satisfactory, however, to make up the convex and concave formers both from a plurality of slats in the manner shown in Figure l.

Figure 5 shows the bending apparatus, in which two face-plates M are shown carrying a former as in Figure 1 on the right, and a former as in Figure 4 on the left. In this arrangement the glass sheet depends from a plurality of gripping tongs A connected to freely swing from chains B.

.This construction permits the sheet or plate of glass to bend freely under the influence of the formers without any resistance from the supporting means, thereby eliminating any tendency toward distortion of the sheet during the bending operation and after the completion thereof. The formers are hung on the face-plates H by hooks I5 engaging the upper edges ofthe faceplates. The apparatus for pressing the two faceplates towards one another is shown on the right only, that on the left being similar. The faceplate is on a frame It comprising a box girder l1, having four guiding surfaces l8. These run between eight rollers l8 (two on each surface l8) carried on the side members 20 of the fixed frame 2|. Thereby the face-plate i4 is able to slide forward and backward (to the left or right respectively as seen in Figure 5). cylinder 22 is fixed by bolts 23 between the side members 20, the box girder I! having an aperture shown by the dotted lines 24 to permit the girder to move to the'left over the cylinder 22. The ram 25 of the cylinder 22 is fixed to the face-plate l4. Pipes 26 provided with valves 26a are connected to an accumulator (not shown) and supply fluid to the two ends of the cylinder 22.

In operation, with "the parts in the position shown in Figure 5, the heated glass sheet, which may be suspended by tongs or otherwise supported, is brought between the two formers, and fluid is supplied to the back ends of the cylinders 22 to force the face-plates It and formers car- 'ried by them together, pressing and bending the glass sheet between them.

Figure 6 shows an alternative form of former, hung on a face-plate ll. A plurality ofiwooden slats I, all of the same width from back to front, are held in a box frame, having upper and lower members 21, so that they are free to slide therein, being guided between the members 2'! and the uprights 2. A former, consisting of two templets 28 attached to the face-plate M by brackets 29,

. is adapted to engage the back edges of the slats I.

A hydraulic In operation, the slats I are pressed back against the templets 28, so that the front surface of the former has the curvature of the templets, and, when the glass is pressed between the formers, the pressure is applied to the glass by the templets 28 and through the slats. In this former when the curvature becomes altered by reason of charring, all the slats of the plurality are again brought to the same length, for instance, by passing them through a thicknessing planer.

Figure 7 shows a former in which a plurality of reglets 30 are held in a frame consisting of the movable sides 3|, 32, 33, 34.

The sides 3| and 32 have slots 35-36 through which pass the bolts 31-38 which pass also through holes 39- in the sides 33-34. In the sides 3|, 32 are also holes "-42 through which pass the bolts 43-.

When the reglets 30 are placed horizontally as shown in the front view 7, the desired curvature is given to the front presented by these reglets by pressing against their outer surfaces a reversely curved templet in a manner similar to that which the slats of the former of Figure l are brought to the desired curvature in conjune-i tion with the templet shown in Figure 3.

The nuts 45-46 of the bolts 4344 are then tightened so as to compress the reglets between the sides "-32. The nuts 41-48 of the bolts 31-38 are in their turn tightened so that the reglets are also compressed between the sides 33- -34.

The reglets thus being held against relative movement by friction, the former shown on this Figure '7 is then brought to the desired position for the bending of glass sheets.

Having described our invention, we declare that what we claim and desire to secure by Letters Patent is:

In apparatus for bending glass sheets, a former including a frame, a plurality of elements held side by side in said. frame. adjustable holding means associated with the frame to hold the elements in any of a plurality of selected positions, and a template having a predetermined. contour carried by the frame and in engagement with the rear edges of the elements for positioning the front edges of the elements to give the front surfaces thereof the curvature of said template.

LEWIS JEX-BLAKE FORBES. GEORGE WILLIAM TERENCE BIRD.

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