JPS6210932B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sharply bending two sheets of laminated glass at the same time.

2. Description of the Related Art Glass plates bent into various shapes are used in automobile windshields, rear windows, etc., depending on design requirements. Recently, with the diversification of the designs of automobiles, etc., and also due to the design requirements of automobiles, laminated glass has come to be required to have a sharply bent shape. In particular, there has been a new demand for laminated glass having a shape in which the sharp bending line 2 of the glass plate 1 is curved in the plane direction of the glass plate, as shown in FIG.

The present invention was invented as a result of studies aimed at providing a method for bending raw glass for laminated glass in order to produce laminated glass having such a shape. In the method of sharply bending a blank sheet for laminated glass along a desired curved bending line, a curve similar to the bending line is formed between the at least two sheets of blank glass for laminated glass along the bending line. sandwiching the ribbon-shaped heater filaments, heat the bending line portions of the at least two laminated glass blanks to a temperature equal to or higher than the softening point of the glass plate by heating the ribbon-shaped heater filaments with electricity; The present invention relates to a method of bending a blank glass for laminated glass, which is characterized in that two blank sheets for laminated glass are simultaneously sharply bent along the curved bending line.

Hereinafter, the present invention will be explained in detail with further reference to the drawings.

In order to relatively sharply bend two or more sheets of glass according to the present invention, the bending line portion is locally heated along the bending line of the desired curved line of the sheet of glass, and the bending line is heated along the bending line. A heater wire serving as a heating means for sharply bending along the bending line by its own weight or by pressing is sandwiched between two or three or more sheets of glass along the bending line of two or more sheets of sheet glass. Arrange with.

The heater strips arranged along the curved bending line of the base glass are most commonly prepared in a predetermined curved shape, but ribbon-shaped heater strips can be used. It is also possible to use a heater in which several parts of the heater filament are held to form a curved shape. Alternatively, it is also possible to use a thin curved heater wire in which a ribbon heater or linear heater is wound around a thin curved core material. In addition, when the raw glass for laminated glass is not only sharply bent along a curved bending line, but also bent in a concave or convex shape in the vertical direction of this bending line, it is possible to follow such bending. Ribbon-shaped heater wires, which are similarly flexible, are optimal.

In the example shown in FIG. 2, a ribbon-shaped heater wire 3 having a curved shape that matches the curved bending line 2 of two pieces of raw glass for laminated glass 1 and 1' is placed along the bending line 2 and 2. Raw glass for laminated glass 1,
1', and electricity is supplied from both ends of the heater wire 3 to heat it.

In this way, the blank glass 1, 1' for bending, in which the heater filament 3 is arranged between two pieces of glass blank 1, 1' along the curved bending line 2, can be used, for example, with the outline of the bent blank glass. Place the blank glass on a bending die for gravity bending, put it into a heating furnace, and heat the entire blank glass to a temperature above its strain point or around its softening point, e.g. 450°C to 670°C.
Heat until. If the heating temperature is higher than 670°C, it will cause doubleness or undesirable deformation of the glass plate, which is undesirable.If it is lower than 450°C, the temperature will be uneven during subsequent heating by the heater strips, leading to the risk of thermal cracking. This is not desirable.

When the base glass 1, 1' reaches the above temperature, a voltage is applied to the heater wire 3, and the heater wire 3 is turned off.
Electric heating is carried out to a temperature of 650° C. or higher, preferably 1000° C. or higher, and the bent line portion of the base glass in contact with the heater filament is locally heated to a temperature higher than the softening point of the base glass, for example, 650° C. or higher.

In the case of gravity bending, when the bending line reaches 650°C or higher, the load of the gravity bending counterweight causes the blank glass to sharply bend along the bending line.

The bending die for this gravity bending process is designed so that the bending line part of the blank glass does not move when the blank glass is bent, and it is advantageous for operation to arrange the heater wire at this position. . For example, when bending the raw glass, if the bending line part of the raw glass is aligned with the line connecting the hinge that connects the bendable part and the non-bending part of the mold, and the heater wire is placed on the line, Since the heater filaments do not move, they can be easily bent.

In addition, when the bending line portion of the blank glass is lowered by gravity during the bending process, the heater filament may be lowered in accordance with the lowering of the bending line portion of the blank glass, if necessary. for example,
There is a method of attaching a guide or fixing device for the heater wire to a part of the member for the gravity bending type that is displaced according to the bending of the blank glass, or a method of installing a separate device to lower the heater wire so that it moves according to the lowering of the glass plate. A method such as lowering the heater filament is used.

In addition, as a method for bending at least two or more sheets of glass for laminated glass, the above-mentioned double bending method is most suitable, but a press bending method may also be applicable.

In the present invention, typical heater wires that generate heat at 650°C or higher and
Made of conductive materials that are stable up to 1200℃ to 1300℃, such as nichrome (nickel-chromium alloy), stainless steel, tantalum, molybdenum, platinum, tantalum alloy, molybdenum alloy, platinum alloy, etc., and has a thickness of 0.05mm to 0.5mm. , a ribbon-shaped heater filament having a width of about 2 mm to 20 mm and an electrical resistance of about 0.1 Ω/m to 10 Ω/m.

Examples of the present invention will be described below.

EXAMPLE As a bending die for sharply bending two glass sheets to be laminated into a shape, a bending die for self-weight bending as shown in FIG. 3 was prepared.

This bending die 10 includes a main body 12 that takes charge of bending the intermediate portion of two glass sheets 11 to be laminated together, and bending parts 14 that are attached to both sides of the main body 12 so as to be able to bend around a support shaft 13. The upper surfaces of the main body part 12 and the bent part 14 act as molding curved surfaces, and at the end of the bending work of the blank glass 11, the shape is substantially the same as the final bent shape of the laminated glass. is formed.

A counterweight 15 is attached to one end of the bent portion 14 for applying a moment that bends the bent portion 14 around the support shaft 13.
It is attached to the mounting arm 16 fixed to 4,
The bending portion 14 allows the blank glass 11 to bend due to its own weight.
This is facilitated by the bending motion of the

The bending die is made so that the bending line of the two sheets of glass coincides with the line connecting the pair of hinges that connect the movable part and the non-movable part, so that the bending position does not move up and down and the heater wires are A device that was designed to be held in constant contact with the raw glass was used.

Further, the bending die 10 is supported by a frame 20 composed of a vertical support member 18, a horizontal support member 19, and a bending die mounting member 13.

The blank glass to be bent into a shape is placed on the above-mentioned gravity bending mold, and the blank glass 1 is
Along the curved bending line 2 of the raw glass to be bent in 1 and sandwiched between the two pieces of raw glass, it is bent into a predetermined shape with a width of 3 mm to 5 mm and a thickness of 0.12 mm to 0.16 mm. Nichrome heater wires 17 in the form of aluminum ribbons were arranged. Above nichrome heater wire 1
Both ends of 7 were held by electrical connection/holding means 22. The voltage to the nichrome heater wire 17 was supplied through the electrical connection/holding means 22 and the power supply means 23.

The raw glass prepared in this way is put into a heating furnace.
The raw glass is heated to 650°C, then 1300W of power is supplied to the nichrome heater wire, heated to 1100°C, and the bending line part of the raw glass is softened.
The force of gravity caused it to bend sharply along a curved bend line.

In addition, in the present invention, in order to hide defects such as optical distortion at the bending line portion and marks caused by heater filaments, at least one sheet of element is used to cover the curved bending line portion of the blank glass. It is also possible to provide an opaque or translucent colored band on the outer surface, inner surface, or both surfaces of the plate glass.

As described above, according to the present invention, two parts for laminated glass necessary for manufacturing laminated glass in which the sharply bent bending line shown in FIG. 1 is curved in the plane direction of the glass plate. Two or three pieces of raw glass can be efficiently bent at the same time into a desired curved bending line and a desired curvature.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a laminated glass whose sharply bent bending line is curved, and Figure 2 is
FIG. 3, an illustration of the method of the invention, shows a perspective view of one embodiment of a bending die used to carry out the invention. 1, 1', 11: Raw glass for laminated glass,
2: sharply bent bending line; 3: heater filament.

Claims (1)

[Scope of Claims] 1. In a method of sharply bending at least two laminated glass blanks to be laminated along a desired curved bending line, the gap between the at least two laminated glass blanks is provided. A ribbon-like heater wire curved in the same manner as the bending line is sandwiched between the ribbon-like heater wires along the bending line, and the ribbon-like heater wire is heated with electricity to form the bending line portion of the at least two blank sheets for laminated glass. A method for bending blank glass for laminated glass, characterized in that the at least two blank sheets for laminated glass are simultaneously sharply bent along the curved bending line by heating the glass to a temperature equal to or higher than the softening point of the glass plate. 2. Claim 1, characterized in that a nichrome heater is used as the ribbon-shaped heater wire.
Method for bending raw glass for laminated glass as described in section.