Glass manufacturing – With fluid support for article or preform – Gaseous support
Reexamination Certificate
1997-05-29
2002-04-02
Vincent, Sean (Department: 1731)
Glass manufacturing
With fluid support for article or preform
Gaseous support
C065S025400, C065S273000, C065S287000
Reexamination Certificate
active
06363751
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for bend-shaping a glass plate so that the glass plate has a complexly curved face and an apparatus for carrying out the process.
2. Discussion of Background
In automobile industries, there has been an increasing demand for a glass plate having a complexly curved face, i.e. a glass plate
8
having a complexly curved face wherein a flat glass plate is bend-shaped with two different radius of curvatures R
1
and R
2
in its longitudinal and transversal directions as shown in FIG.
3
.
FIG. 4
shows an example of a bend-shaping apparatus proposed as an apparatus for bend-shaping a glass plate to have a complexly curved face (Japanese Examined Patent Publication No. 10331/1974). With use of a bend-shaping apparatus
10
, a glass plate
8
is bend-shaped to have a radius R
2
along the axis perpendicular to the transferring direction while it is transferred on hearth beds
13
,
13
and then, the glass plate
8
is bend-shaped to have a radius R
1
along the axis of the transferring direction on hearth beds
14
,
16
each of which has a portion curved along the axis of the transferring direction, and then it is cooled and strengthened at a blowing port
18
, whereby a complexly curved face is formed in the glass plate
8
as shown in FIG.
3
.
A shaping furnace constitutes a very large portion of the investment for such glass manufacture line. Accordingly, it is advantageous if equipment for a conventional glass plate manufacture line for producing a glass plate having a simply curved face can be used for a glass plate manufacture line which is used for producing a glass plate having a complexly curved face. In particular, it is advantageous if the shaping furnace for the conventional manufacture line can be used in common. However, there were many difficulties in using the same shaping furnace for both types of curved glass plates. Namely, when it is desired that the glass plate manufacture line for a glass plate having a simply curved face, which is already equipped, is used for a glass plate manufacture line for a glass plate having a complexly curved face as shown in
FIG. 4
, it is necessary to replace the hearth beds
14
,
16
and the blowing port
18
in the glass plate manufacture line for a glass plate having a simply curved face by those for a glass plate having a complexly curved face. In the conventional bend-shaping apparatus for producing a glass plate having a complexly curved face, however, there was a large distance in the vertical direction between the level H
2
of the position where the glass plate is not yet bend-shaped and the level H
1
of the position where the glass plate has been bend-shaped. The distance is indicated by H in FIG.
4
. Namely, if the shaping furnace of the glass plate manufacture line for a glass plate having a simple curved face is to be used in common for the glass plate manufacture line for a glass plate having a complexly curved face, it is necessary to provide a special raising means for raising a glass plate, which has been bend-shaped in the longitudinal direction, from the lower level H
1
to the higher level H
2
in a case that the glass plate having a complexly curved face is to be manufactured.
The lower level H
1
varies depending not only on the difference between the nature of the glass plate having a simply curved face and the nature of the glass plate having a complexly curved face but also on the specification of the glass plate having the complexly curved face. Namely, such raising means has to be either of an inclusive use which is separately prepared depending on the specification for bend-shaping the glass plate, or has to be used after the adjustment of an existing raising means depending on the specification. The preparation of several types of raising means for inclusive use depending on the type of glass plate is not preferable because a large investment for equipment is required. The adjustment of the existing raising means is not practical because much time and labor are required when the type of glass plate to be manufactured is changed. In addition, in practice, there are many difficulties from a technical viewpoint to raise the glass plate from the lower level H
1
to the higher level H
2
.
Namely, in the conventional glass plate bend-shaping line for bend-shaping a glass plate having a simple curved face, the distance L between a shaping furnace
12
and a post-treating conveyor
20
is determined to be short (generally, several meters or shorter) in order to reduce equipment space as much as possible. Accordingly, when the shaping furnace in the existing glass plate shaping line for a glass plate having a simply curved face is used for the production of a glass plate having a complexly curved face, it is necessary to raise the glass plate from the lower level H
1
to the higher level H
2
in the relatively short distance L.
In such conditions, it is very difficult to stably transfer the glass plate in that distance because the radius of curvature and the gradient of the transferring surface of the blowing port
18
are different from those of the transferring surface of the raising means. Such difficulty can be eliminated if the distance L can be enlarged to more than 10 meters. However, this does not meet the demand of saving space, and it is impossible to use the existing manufacture line for a glass plate having a simple curved face for the manufacture line for a glass plate having a complexly curved face.
SUMMARY OF THE INVENTION
It is an object of the present invention to eliminate the disadvantage described above and to provide a process for bend-shaping a glass having a complexly curved face and an apparatus for carrying out the process, which enables the utilization of most of the equipment of the existing manufacture line for a glass plate having a simple curved face and which is sufficient for only simple change of equipment.
It is another object of the present invention to provide a process for bend-shaping a glass plate having a complexly curved face and an apparatus for carrying out the process which can operate in a small space of equipment.
Another object of the present invention is to permit the common use of the shaping furnace for a glass plate having a simply curved face and the shaping furnace for a glass plate having a complexly curved face in spite of various kinds of specification.
Another object of the present invention is to standardize an amount of a decrease in elevation of a glass plate from a higher position H
2
(the position of the glass plate before falling) to a lower position H
1
(the position after the falling) during the operation of shaping the glass plate to have a complexly curved face, so that a raising means to raise the glass plate can be used commonly irrespective of the specification of bending the glass plate having a complexly curved face. Thus labor necessary for adjusting the equipment for bend-shaping the glass plate at the time of changing the specification of the glass plate can be reduced.
It is another object of the present invention to improve stability in raising the bent glass plate by reducing the length of transferring the glass plate.
In accordance with the present invention, there is provided a process for bend-shaping a glass plate by heating the glass plate to a temperature which is close to a softening temperature of the glass plate, while the glass plate is transferred in a transferring direction along a transferring surface in a shaping furnace, to thereby bend the glass plate, by its own deadweight, into a shape corresponding to the shape of the transferring surface, comprising the steps of:
complexly bending the glass plate in the shaping furnace by transferring the glass plate along a complexly bending transferring surface comprising hearth beds having bend-shaping surfaces, said complexly bending transferring surface having a complexly curved face which is upwardly projected with predetermined radius of curvatures along both an axis of the
Hirotsu Takashi
Nagaoka Teruji
Ohtani Kazuyoshi
Asahi Glass Company Ltd.
Vincent Sean
LandOfFree
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