JPH06305751A - Glass lens molding device - Google Patents

Abstract

PURPOSE:To shorten the temp. resetting time of a heating furnace and to provide the molding device having good productivity with shorter cycle time by making it possible to set a temp. difference outside a heating furnace in a manner as not to exert influence on this heating furnace. CONSTITUTION:This glass lens molding device is composed of a transporting section for transporting a glass blank material 5 to be molded and the molded glass lens, the heating furnace 9 for heating and softening the glass blank material 5 transported via a transporting arm of this transporting section and a temp. control section (temp. control ring 6) which is arranged separately from the heating furnace and is constituted to control the temp. of the heated glass blank material 5. As a result, the temp. control section for increasing the temp. of the thick part of the glass blank material 5 higher than the temp. of the thin part thereof is constituted and arranged as a separate body from the heating furnace 9, by which the temp. of the heating furnace is kept always constant and the molding with the short cycle time and the good productivity is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus for press-molding a heat-softened glass material with a pair of molding dies to obtain a glass lens.

[0002]

2. Description of the Related Art Generally, when a glass lens that has been softened by heating is molded into a glass lens at a temperature lower than the temperature of the glass material, the glass material is cooled according to the thickness difference of the glass material during cooling during molding. The thin part first solidifies and the part where the total pressing force is solidified receives, and no pressure is applied to the high temperature part that is not yet fully solidified, and when the molding is completed, the temperature is high and the pressure is high. There is a problem that the part that does not take up becomes a sink mark and does not transfer to a predetermined shape.

As a glass forming apparatus for solving this kind of problem, an apparatus disclosed in Japanese Patent Laid-Open No. 2-133325 has been proposed. That is, in the method of forming a glass material with a large thickness difference, by making the temperature of the thin portion of the glass material higher than the temperature of the thick portion, the glass material inside As a device for eliminating the temperature difference, there is disclosed a device for providing a temperature difference between a thick portion and a thin portion of the glass material by a temperature control rod provided in a heating furnace for heating the glass material.

[0004]

However, in the apparatus disclosed in the above-mentioned Japanese Patent Laid-Open No. 2-133325, the glass material is heated in order to provide a temperature difference between the thick part and the thin part of the glass material. Since the temperature control rod is installed in the heating furnace that softens, the temperature inside the heating furnace fluctuates each time, and it takes time for the furnace temperature to return to a constant level. It had a drawback that it could not be molded.

The present invention has been made in view of the above-mentioned problems of the prior art, and does not have a temperature difference between the glass materials in the heating furnace as in the prior art, and does not affect the heating furnace. By providing a temperature difference outside the heating furnace, the temperature recovery time of the heating furnace is shortened, and a molding apparatus with a short cycle time and good productivity is provided.

[0006]

In order to achieve the above-mentioned object, a molding apparatus of the present invention comprises a carrying section for carrying a glass material to be molded and a molded glass lens, and a carrying arm of the carrying section. A heating furnace for heating and softening the glass material to be conveyed, a molding chamber for press-molding after heating, and a temperature for controlling the temperature of the heated glass material arranged separately from the heating furnace. It is composed of a tuning unit.

[0007]

With the above structure, the temperature control part for increasing the temperature of the thick part of the glass material is higher than that of the thin part of the glass material. A temperature difference can be provided to the raw material immediately before press molding, the temperature of the heating furnace can always be kept constant, and molding with a short cycle time and good productivity can be performed.

[0008]

Embodiment 1 FIGS. 1 to 5 show this embodiment,
FIG. 1 is a conceptual diagram of a glass forming apparatus of the present invention, and illustrates a method for forming a concave glass lens having a thin central portion.

First, the structure of this apparatus will be described with reference to the drawings. As shown in the figure, the glass molding apparatus 1 includes a molding body 4 equipped with upper and lower molding dies 2 and 3, a temperature control ring drive 6 for heating and cooling a heated glass material 5,
The glass material 5 placed on the rail 7 is preheated in the furnace 8,
The main heating furnace 9 and a transfer arm driving unit 12 for transferring to a molding point 11 in the molding chamber 10 and an apparatus base 13 are provided.

The upper and lower molding dies 2 and 3 are arranged in a molding chamber 10 formed by a cover 16 and an upper plate 17 which are erected on a lower plate 15 fixed to a table 14 on an apparatus base 13. I am doing it. The upper mold 2 is fixed to a holder 18 fixed on the inner surface of the upper plate 17 via a mounting ring 19, and the lower mold 3 is supported by a bearing 20 mounted on the table 14 so as to be vertically movable. The movable shaft 21 is fixed via a mounting ring 22. In addition, 22 and 23 are heaters.

In the molding chamber 10, a temperature control ring 2 having a built-in heater for heating and cooling the glass material 5 after heating.
6 is fixed to a horizontally rotatable temperature control arm 27 via a drive unit 6, and is coaxially arranged between the upper and lower molds 2 and 3. The transfer arm drive unit 12 is a transfer arm drive unit 12.
Is for driving the transfer arm 28 up and down and back and forth, and is configured so that the transfer arm 28 can be stopped and controlled at each position of the preheating furnace 8, the main heating furnace 9 and the molding point 11.

A plurality of glass materials 5 are placed and supported on the rails 7 via the transport member 29, are sequentially fed into the preheating furnace 8 from a supply chamber (not shown), and are positioned at the tip of the transport arm 28. It is adapted to be transferred to and supported on the support portion 30. The preheating furnace 8 is for preheating the glass material 5 on the rail 7 together with the conveying member 29 to a temperature near the glass transition point of the glass material. The main heating furnace 9 is for heating and softening the preheated glass material into a moldable state.

Next, the operation based on the above configuration will be described. In this example, a biconcave lens was molded. The glass member 5 on which the glass material 5 to be molded is placed passes through the preheating furnace 8 to heat the glass material 5 to a temperature near the glass transition point. When the transfer arm 28 is reached, the transfer arm 28 is moved forward, and the support portion 30 at the tip of the arm
After the transport member 29 is fitted to the rail, the transport member 29 is transferred from the rail by raising the arm (FIG. 2).
reference).

Next, the transfer arm 28 is advanced into the main heating furnace to heat the entire glass material 5 to a temperature above the softening point in the main heating furnace 9 (see FIG. 3). Next, the transfer arm 28 is moved forward and moved into the molding chamber 10. The transfer arm 28 is stopped at a position where the centers of the transfer members 29 on the axes between the upper and lower molds in the molding chamber 10 are aligned with each other, and the transfer arm 28 is lowered to wait for temperature control waiting downward. The transport member 29 is transferred to the ring 26 (see FIG. 4). The transfer member 29 is cooled by transferring the transfer member 29 to the temperature control ring 26 whose temperature is adjusted to the same temperature as the mold, whereby the glass material 5 placed on the transfer member 29 is cooled. At this time, the glass material 5 is cooled from the outer peripheral edge and the side surface of the lower surface which is in contact with the conveying member 29, and the central portion is gradually cooled. Therefore, when the glass material 5 is placed on the temperature control ring 26 for a long time, the entire glass material 5 is cooled to the same temperature as the temperature control ring 26, so that all of the glass material 5 has the same temperature as the temperature control ring 26. In other words, in other words, when the temperature difference between the outer peripheral portion and the central portion of the glass material 5 occurs, press molding is performed by the molding die.

Here, the temperature adjusting ring 26 is brought into contact with the temperature adjusting ring 26 by adjusting the temperature lower than the temperature of the glass material 5 to be almost the same as the temperature of the upper and lower molds (near the glass transition point). The outer peripheral portion of the conveying member 29 is cooled, and the glass material 5 is also cooled from the outer peripheral portion along with it. In the cooling process, the temperature of the thick portion (peripheral portion) of the glass material 5 is made lower than the temperature of the thin portion (central portion). Can decrease.

FIG. 5 shows a graph of the temperature change in that case. The glass material 5 uniformly heated in the heating furnace 9 to a temperature T ₀ equal to or higher than the glass softening point is brought into contact with a temperature control ring heated to a temperature T ₂ near the glass transition point, whereby the thickness of the glass material 5 is increased. The thin portion b and the thin portion a are cooled while having a temperature gradient as shown in the graph. The lower molding die 3 is moved upward in accordance with the time t ₁ at which the temperature gradient during the cooling becomes maximum (T ₂ −T ₃ ), and the conveying member 29 is pushed up from the temperature control ring 26 and then further raised. And press-mold with the upper molding die 2.

After the molding process is completed, the lower mold 3 is lowered, and then the conveying member 29 is dropped on the temperature adjusting member 26.
Further, the temperature control ring 26 is horizontally rotated to collect the temperature control ring 26 outside the molding chamber. Hereinafter, this is repeated to perform continuous molding.

As described above, according to the molding apparatus of this embodiment, the temperature control ring installed outside the heating furnace forcibly causes a temperature distribution in the glass material. There is no need to make fluctuations, temperature recovery in the heating furnace is not necessary, and molding can be performed in a short time. In addition,
In the case of a convex lens, by adjusting the temperature of the temperature control ring to the same temperature as the heating furnace, the thick part (peripheral part)
Since the temperature can be lower than the temperature of 1, the molding can be performed by the same method as described above. In the present embodiment, the biconcave lens is molded, but the present invention is not limited to this, and the same effect as above can be obtained as long as the lens has a larger peripheral wall thickness than the central part such as a plano-concave lens and a concave meniscus. Obtainable.

[0019]

According to the present invention, it is possible to reduce the temperature fluctuation of the heating furnace as compared with the prior art, so that molding with a short molding cycle time and good productivity can be carried out.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a glass forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the embodiment.

FIG. 3 is an enlarged view of a main part of the embodiment.

FIG. 4 is an enlarged view of a main part of the embodiment.

FIG. 5 is a graph showing a relationship between temperature and time in a thin portion a and a thick portion b of the glass material.

[Explanation of symbols]

 1 Glass Molding Equipment 2 Upper Mold 3 Lower Mold 4 Molding Main Body 5 Glass Material 9 Heating Furnace 10 Molding Chamber 26 Temperature Control Ring

Claims (1)

[Claims] 1. A glass lens forming apparatus configured such that a glass material is placed and supported and can be carried in and out at a predetermined position in a heating furnace and a molding chamber, and the glass material heated in the heating furnace is heated. A glass lens forming apparatus, characterized in that a temperature adjusting portion comprising a temperature adjusting ring for adjusting the temperature later is arranged between the upper and lower molds.