Glass manufacturing – Processes – Glass preform treating
Reexamination Certificate
2001-02-20
2004-04-20
Griffin, Steven P. (Department: 1731)
Glass manufacturing
Processes
Glass preform treating
C065S348000, C065S351000
Reexamination Certificate
active
06722160
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an air-cooling/tempering device and an air-cooling/tempering method for a glass plate used for transporting machines such as automobiles, ships, railways, airplanes and so on or other various usage such as buildings and so on.
BACKGROUND ART
There has been known a method for bend-shaping a glass plate by transferring a glass plate heated to around a softening temperature in a heating furnace on a roller conveyor comprising a plurality of curved rollers (in, for example, U.S. Pat. No. 4,123,246). According to this method, the softened glass plate falls by its own weight, so that the glass plate is bent to meet the curvature of the rollers. In this case, the glass plate is bend-shaped in a direction perpendicular to a transferring direction of the glass plate.
In description, bend-shaping in a direction perpendicular to a transferring directions means that the shape of a bend-shaped glass plate is a shape curved around the axis of the transferring direction. In other words, the bend-shaped glass plate has a curved shape in cross section taken vertically along the axis of the transferring direction. “Bend-shaping along a transferring direction” means similarly that the shape of a bend-shaped glass plate is a shape curved around the axis perpendicular to the transferring direction. In other words, the bend-shaped glass plate has a curved shape in cross section taken vertically along the axis perpendicular to the transferring direction. With respect to the shape of a curved plane formed by a plurality of rollers as described hereinbelow, “curved in (along) a transferring direction”, “curved in a transferring direction” or the like have the same meaning as “bend-shaped in (along) a transferring direction”. Also, in description of the curved plane concerning a direction perpendicular to a transferring direction, the same meaning as “bend-shaped in a direction perpendicular to a transferring direction” should be taken.
In this description, “perpendicular to a certain direction” means a direction perpendicular to a certain direction on a horizontal plane. Further, “upper” or “lower” in this description means “upper” or “lower” with respect to a horizontal plane.
In automobile industries in recent years, a demand of production of small quantity and large variety has been increasing, and glass plates having various curvatures are needed so as to correspond to models of automobiles. In a method described in U.S. Pat. No. 4,123,246 (hereinbelow, referred to simply as the '246 method), it was necessary to exchange rollers to those having a curvature corresponding to a model of automobile. The exchanging took much time, and it was necessary to prepare rollers having a curvature required for the model.
Further, in the '246 method, glass plates are transferred in a direction perpendicular to a direction to be bent. In this case, in bend-shaping a glass plate for a side window of an automobile for instance, the direction of a side of the glass plate when it is fitted to an automobile, corresponds to the direction of extending of the rollers. Accordingly, a stripe-like roller strain due to the contact of the rollers to the glass plate is formed in a vertical direction in a state of being assembled, and therefore, the stripe-like strain by the rollers is apt to be conspicuous. With respect to this, detailed description will be made hereinbelow.
When a glass plate is transferred by means of rollers, a so-called roller strain is formed by the contact of the glass plate with the rollers. Each of the rollers is extended in a direction perpendicular to the transferring direction, and they are arranged adjacently in the transferring direction. Therefore, the roller strain is formed in a stripe form in a direction perpendicular to the transferring direction of the glass plate.
Usually, it is difficult to find the roller strain by human eyes, and the roller strain is never an obstacle to visibility in use. However, it is seldom to find the roller strain depending on a condition of use and light incident to the glass plate. For example, a stripe-like strain extending in a vertical direction of a glass plate in a state that the glass plate is assembled to an automobile is easy to see in comparison with a stripe-like strain extending in a horizontal direction in an assembled state. Accordingly, it is preferred to make the transferring direction of the glass plate to be bend-shaped coincident with a horizontal direction in an assembled state.
On the other hand, when a glass plate is bend-shaped along the transferring direction, the thickness in apparent of the glass plate viewed from the frontage of an air-cooling/tempering device becomes large. Accordingly, in a conventional air-cooling/tempering device for a glass plate, a large frontage is required. When the frontage is made large, the distance between the air-blowing ports of the air-cooling/tempering device and the surface of the glass plate is large whereby the cooling performance is reduced.
As a bend-shaping method for a glass plate wherein the transferring direction of the glass plate to be bend-shaped is made coincident with the horizontal direction in an assembled state, and the frontage for introducing glass plates in the air-cooling/tempering device is made small, the method as described in U.S. Pat. No. 4,820,327 is known. According to this method, a glass plate is bend-shaped by heating the glass plate to around a softening temperature in a heating furnace and transferring the glass plate by means of a plurality of rollers arranged with an inclination in the transferring direction so as to curve the transferring path. In this method (hereinbelow, referred to as the '327 method), since the softened glass falls by its own weight, the glass plate is bent to meet a curvature of the transferring path. In this case, the glass plate is bend-shaped in the transferring direction.
In the '327 method, however, it was necessary to change the arrangement of rollers so as to form a transferring path having a curvature which meets a specified model among various models. The exchange took much time. Further, in the '327 method, the transferring direction of the glass plate is changed to a vertical direction. Therefore, the entire equipment used for the '327 method is inevitably large. Further, the transferring direction of the glass plate has to be changed from the vertical direction to the horizontal direction whereby a complicated mechanism is needed.
The glass plate bend-shaped as described above is, then, transferred to the air-cooling/tempering device in which air-cooling and tempering are effected. In this case also, the glass plate is air-cooled and tempered while it is transferred by a roller conveyor. Namely, the glass plate is transferred by the roller conveyor, wherein in such transferring process, the glass plate is air-cooled and tempered by blowing air to its upper and lower faces through air-blowing heads arranged upper and lower sides of the roller conveyor. In this case, the air-cooling/tempering device is preferably so adapted that the blowing of air is started when the entirety of the glass plate has completely been transferred between the upper and lower air-blowing heads so that the entire surface of the glass plate can uniformly be air-cooled and tempered. Namely, the air-cooling/tempering device is formed such that the blowing of air is started when the entirety of the glass plate is transferred between the upper and lower air-blowing heads, and the blowing of air is stopped when the glass plate is completely passed through the air-blowing heads. Then, the blowing of air is started again when the next glass plate to be air-cooled and tempered is, in its entirety, completely transferred between the upper and lower air-blowing heads.
However, the conventional method has a weak point such that in air-cooling and tempering the glass plate, another glass plate to be subsequently air-cooled and tempered can not be transferred between the upper and lower air-blowin
Nemugaki Yoichi
Nomura Ken
Tomioka Masanori
Asahi Glass Company Limited
Griffin Steven P.
Lopez Carlos
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