JPH0339464Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a press molding machine for glass lenses, and particularly to a press molding machine for glass lenses having a sharp prism element.

[Technology background]

Conventionally, when press molding is performed from molten glass, a molding machine is often used in which a molten glass gob is supplied onto a mold assembly of a press molding machine, and the gob is pressed by a plunger of the press molding machine.

However, with this type of press molding machine that has been used conventionally, when pressing an article with sharp irregularities on the molding surface, such as a lens for a vehicle lamp, the plunger is At the tip of the prism-forming element, the flow direction of the supplied molten glass changes suddenly, and at that time surrounding air is drawn into the molten glass, which has the disadvantage of easily producing glass products with wrinkles and bubble defects. It was hot.

Therefore, a molten glass gob press molding machine has been proposed which eliminates this drawback and does not involve surrounding air into the molten glass during press working.

FIG. 3 shows a sectional view of a molten glass gob forming machine that does not involve surrounding air into the molten glass during press working.

In FIG. 3, 1 is a plunger of a press molding machine, 4 is a mold assembly, and 7 is a glass gob.

In the molten glass gob press molding machine shown in FIG. 3, when the glass gob 7 supplied to the mold assembly 4 is pressed, the flow direction of the molten glass gob suddenly changes at the tip of the prism forming element of the plunger. In order to prevent air from being drawn into the glass and causing bubbles or wrinkles, the tip of the prism-forming element of the plunger is rounded to slow the change in the flow direction of the glass.

However, this conventional press molding machine has the disadvantage that, because the tip of the prism forming element is rounded, the molded glass lens generates unnecessary diffused light and has poor optical properties.

Therefore, in order to eliminate this drawback and press-mold a glass lens with excellent optical performance, a method of press-molding a glass lens from a molten glass sheet instead of using a molten glass gob has been developed. This is proposed in Japanese Patent Application Laid-Open No. 58-64226.

FIG. 4 shows a press molding machine disclosed in Japanese Patent Application Laid-Open No. 58-64226, and 1 and 4 are plungers and mold assemblies similar to those explained in FIG. 3. Further, 5 is a trimmer, and 6 is a molten glass sheet.

Similarly to the press molding machine shown in FIG. 3, the molten glass sheet press molding machine shown in FIG. The process involves molding a glass lens with a

[Problem that the invention attempts to solve]

However, in the molten glass sheet press molding machine disclosed in JP-A-58-64226,
In the case of press processing of glass products that require a prism forming element mainly on the plunger side, such as glass lenses for vehicle lights, the degree of glass flow during press molding is smaller than in the glass gob press molding method. Therefore, air is trapped in the recess of the prism forming element of the plunger, causing wrinkles and bubble defects, which is not sufficient.
However, there were some problems.

[Means for solving problems]

The present invention was made to solve the above-mentioned problems, and when press-molding a molten glass sheet, the molten glass sheet is pressed by a sharp or prism molding element and a plunger having air vent grooves or holes. By molding,
It is an object of the present invention to provide a molten glass sheet press molding machine capable of producing a glass lens in which air is difficult to accumulate in the recesses of a prism-forming element and, therefore, wrinkles and bubble defects do not occur inside.

[Effect of invention]

In the present invention, when pressing a molten glass sheet, the air that accumulates in the recess of the prism forming element of the plunger passes through the vent groove or hole and escapes to the outside of the plunger, which prevents wrinkles and bubbles from forming on the glass product, especially on the glass lens. There is no.

[Example of idea]

The present invention will be explained in detail based on the drawings.

FIG. 1 is a sectional view of a press molding machine showing the basic configuration of an embodiment of the present invention, where 1 is a plunger;
2 is a prism forming element, 3 is an air vent groove, 4 is a mold assembly, 5 is a trimmer, and 6 is a molten glass sheet.

FIG. 2 is a bottom view of the plunger 1. The plunger 1 is provided with a prism forming element 2 having a sharp shape and an air vent groove 3 in its recess. When the molten glass sheet 6 is placed on the mold assembly 4 and pressed by the plunger 1, a prism glass lens is formed by the prism element 2 at the tip of the plunger 1. Since the prism molded element 2 of No. 1 has a sharp shape, it does not involve surrounding air, and the air accumulated in the recess of this prism molded element 2 is discharged through the air vent groove 3 provided in this recess.
escape through. As a result, at the tip of the prism-forming element of the plunger, air is not entrained or air is trapped in the recess.

In this embodiment, an air vent groove 3 is arranged at the tip of the plunger 1 in order to remove air from the recess of the plunger 1, but the same result can be obtained even if a large number of air vent holes are arranged in the recess at the tip. Obtainable. Furthermore, the molten glass sheet 6 is meant to be flat in advance, and does not necessarily have to be formed into a sheet. With regard to these air vent grooves or holes, if the groove width or hole diameter is made as small as possible, defects such as minute cracks caused by glass digging into the groove width or hole diameter will not occur.

[Effect of idea]

According to the present invention, with an extremely simple configuration,
When press-molding molten glass, it has the excellent effect of solving both the problems of air being trapped at the tip of the prism-forming element of the plunger and air pockets in the recesses of the prism-forming element.

In addition, since the groove width or diameter of the air vent groove or hole in the recess of the prism forming element of the plunger can be made small, the glass will not dig into the groove width or hole diameter and cause microcracks.

Furthermore, since the tip of the prism-forming element of the plunger can be made very sharp, it is possible to reduce the generation of unnecessary diffused light caused by rounding the tip of the prism-forming element, making it possible to obtain a glass lens with excellent optical properties. It has an extremely excellent effect.

In addition, in terms of the thermal load on the tip of the prism forming element of the plunger, the present invention eliminates the imbalance of thermal load between the part that comes into contact with the glass gob and the other parts in the early stage of molding, which is inherent in glass gob press molding. Since the mold temperature is uniform in all prism elements of the plunger, it has an excellent effect in terms of moldability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a press molding machine showing the basic configuration of an embodiment of the present invention, FIG. 2 is a bottom view of its plunger, and FIG. 3 is a conventional molten glass gob press molding machine. The figure shows another conventional press molding machine. In the figure, 1: plunger, 2: prism forming element, 3: air vent groove, 4: mold assembly, 5: trimmer, 6: molten glass sheet, 7: molten glass gob.

Claims (1)

[Scope of utility model registration request] A molding machine for press-molding glass lenses by press-molding molten glass is equipped with a plunger having a sharp prism-forming element at the tip, and the plunger has an air vent in the recess of the prism-forming element at the tip. A glass lens press molding machine characterized by having grooves or holes.