JPS62182120A - Electric furnace in glass forming apparatus - Google Patents

Abstract

PURPOSE:The titled apparatus, obtained by constructing the inside wall surface of an electric furnace in a glass forming apparatus from glass tubes and capable of preventing the oxidative corrosion of the inside wall and giving molded articles having good molded surfaces. CONSTITUTION:An electric furnace 1 having quartz glass tubes 46 integrally fixed on the inside wall surfaces of a cylindrical heat transfer member 47 of a cylindrical heater part 45 constituted of the cylindrical heat transfer member 47, resistance 48 wires embedded in the heat transfer member 47 and a metallic cover 49 integrally covering the outer periphery of the heat transfer member 47 in a glass forming apparatus is fixed on a table 15 through a heat insulating material 50 and supporting stands 51.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electric furnace in a glass forming apparatus for heating and softening an optical glass material (gob) to a moldable state prior to molding the optical glass material (gob). Regarding.

[Prior Art] Generally, when heating and softening an optical glass material to a moldable state, the temperature is 600° C. or higher.

■! It is necessary to heat the glass to a temperature higher than the transition point temperature of the glass, and an electric furnace is used as a heating means for this purpose. As for the construction of this electric furnace, it is customary to use a metal wall for the inner wall surface.

[Problems to be Solved by the Invention] However, the electric furnace having the above conventional configuration has the following problems.

That is, as mentioned above, it is necessary to heat the inside of the electric furnace to a temperature higher than the transition point of glass, for example 600°C or higher, so the inner wall made of metal is oxidized and corroded due to this temperature. There was a major problem in that oxides (corrosive substances) adhered to the surface of the optical glass 7 material during heat-softening treatment, significantly deteriorating the quality of molded products (glass lenses, etc.).

The present invention has been made in view of the problems of the prior art described above, and provides a good molding surface even when an optical glass material is heated and softened in an electric furnace under high temperature conditions higher than the transition point temperature of the glass. An object of the present invention is to provide an electric furnace in a glass forming apparatus that can obtain a molded product having the following characteristics.

[Means and effects for solving the problems] The present invention provides an electric furnace in a glass forming apparatus for heating and softening an optical glass material to a molded state. It is designed to keep the surface of the optical glass material in a clean state at all times.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

(First Example) Fig. 1 shows an optical glass element f (optical glass material) 2 (see Fig. 2) equipped with an electric furnace (main heating furnace) ■ according to the present invention.
It is a perspective view of the glass forming apparatus 3 for forming, and FIG.
FIG. 2 is a schematic explanatory diagram of the glass forming apparatus 3 shown in cross section to facilitate understanding of each configuration in FIG. 1. FIG.

As shown in the figure, the glass molding device 3 has upper and lower molds 4.
．． 5, a mold release ring drive unit 7 for releasing the molded glass lens from the upper and lower molds 4.5, and an optical glass element 2 placed on a magazine 8. Preheating furnace 9゜Main heating furnace (electric furnace) 1 and molding chamber 1
It is composed of a transport arm driving section 13 for transporting the molding point 12 to a molding point 12 within the molding point 1, a 14th apparatus base, and the like.

The upper and lower molds 4.5 are placed on the table 15 of the device base 14.
It is arranged in a molding chamber 11 formed by four pillars 17 erected on a lower plate 16 fixed to the upper plate 19 and a cover 18 closing the periphery thereof. The upper mold 4 has a mounting ring 21 attached to a holder 20 fixed to the inner surface of the upper plate 19.
The lower die 5 is fixed via a mounting ring 24 to a movable shaft 23 which is supported via a bearing 22 mounted on the table 15 so as to be vertically movable. 25
．． Reference numeral 26 indicates a heater.

Release rings 27 and 28 are loosely fitted into the upper and lower molds 4.5 for releasing the molded glass lenses from the molds 4 and 5, and each mold release ring 27 and 28 is driven by a drive The mold releasing function is performed through the upper and lower arms 29 and 30 which are moved by ↑° through the part 7. The movable shaft 23 on which the lower die 5 is fixedly mounted is set to be vertically driven by an eccentric cam 32 which is rotationally driven via an encoder 31.

The transfer arm drive unit 13 is for driving the 4&I feed arm 33, and is set so that the transfer arm 33 can be stopped at the preheating furnace 91, the heating furnace 10, and the molding point 12. The optical glass element 2 is mounted and supported on a magazine 8 via a gob plate 34, and the gob plate 34 on the magazine 8 is attached to the tip of a transport arm 33 as shown in FIGS. 3(a) and 3(b). A gob plate support portion 35 formed in the
It has been moved to F and is now supported. Is the gob plate 34 on the magazine 8 supported by the transport arm 33?
The configuration to be transferred onto B35 is shown in Fig. 4 (a), (b), (
As shown in c) and (d), that is, as shown in FIGS. 2 and 4 (L), a cylinder 36 for pushing up the gob plate 34 is disposed below the magazine 8. Figure (b
), the gob plate 34 is attached to the protruding L part 38 at the tip of the piston rod (movable rod) 37 of this cylinder 36.
It is set so that it can be temporarily operated from above the magazine 8. *The feed arm 33 is placed on the side of the magazine 8, and is moved in the direction of arrow 39 in FIG. 4(b) via the drive unit 13, as shown in FIG. 4(C). , so that the piston rod 37 is moved through the groove 40 to a position where the axial center of the piston rod 37 is coaxial with the axial center of the gob plate support 35. Then, by lowering the piston rod 37 in the state yE shown in FIG. 4(C), the gob plate 34 is moved from the gob book supporting portion 35 of the transfer arm 33 to It is configured so that it can be transferred to E.

The magazine 8 on which a plurality of gob plates 34 are placed is located in the supply chamber 41.
A magazine 8 is designed to be transported sequentially from the inside and supports the gob plate 34 on which the glass lens after molding is completed.
is configured to be stored in the storage chamber 42. Each gob plate 34 on the magazine 8 that is sequentially transported from inside the supply chamber 41 is first controlled to stop inside the preheating furnace 9. The preheating furnace 9 is for preheating the glass optics 27-2 on the magazine 8 together with the gob plate 34 to a temperature of about 400°C. It is configured so that it can be used.

The glass optics unfinished-2 preheated in the preheating furnace 9 is transported by the gob plate transfer mechanism shown in FIGS. 4(a), (b), (c), and (d). It is set so that it is transferred onto the arm 33, transported into the main heating furnace (electric furnace) l via the transport arm 33, and controlled to stop. The heating furnace 1 heats the preheated optical glass element 2 to a temperature above its transition point.

For example, it heats at a temperature of 600° C. or higher to soften the optical glass element 2 into a molded workable IE, and is configured in an electric furnace.Water heating furnace II: configured in an electric furnace This is because a high temperature atmosphere sufficient to heat and soften the optical glass material 2 can be obtained.

The water heating furnace, that is, the electric furnace 1 is shown in FIG. 5(a).

As shown in (b), the cylindrical heater part 45 and the heater F
l! It is composed of a quartz glass tube 46 provided on the inner peripheral surface of A45. The cylindrical heater section 45 is connected to the cylindrical heat transfer member 4
7, a resistance wire 48 embedded in the heat transfer member 47, and a metal cover 49 that integrally covers the outer periphery of the heat transfer member 47, and these quartz glass tubes 46. Heat transfer member 47, resistance wire 48. The metal cover 49 constitutes an integrated electric furnace l. The electric furnace 1 is fixed on a table 15 via a heat insulating material 50 and a support stand 51.

Next, the operation based on the above configuration will be explained.

Among the gob plates 34 on the magazine 8 discharged from the supply chamber 41, when the gob plate 34 on which the glass optical element P2 to be molded is mounted reaches the preheating furnace 9, the magazine 8
is stopped, and the optical glass element 2 together with the gob plate 34 is preheated to about 400° C. via the infrared heater 43.

Next, Figure 4 (a), (b), (c), (
In the sequence of operations shown in d), the preheated optical glass element 2 and the gob plate 34 are transferred from the top of the magazine 8 to the transfer arm 33. Then, the gob plate 34 is transported into an electric furnace (main heating furnace) (1) via the transport arm 33, stopped at a predetermined position, and the optical glass element 2 is heated to a temperature near the transition point, for example, 600°C or higher. Heat to temperature. Thereby, the optical glass element 2 is heated and softened to a moldable state.

The optical glass element 2 heated and softened in the electric furnace 1 is transported into the molding chamber 11 via the transport arm 33, and is controlled to stop when the optical glass element 2 reaches the molding point 12. Then, the movable shaft 23 equipped with the lower mold 5 is moved by the rotation of the eccentric cam 32, and the optical glass element 2, which has been heated and softened, is pressed into a predetermined shape by the lower mold 5 and the upper mold 4. molded. The completed glass lens of the JA type is released from the mold via the release rings 27 and 28, and is again passed onto the gob plate 34 and placed on the bottom of the magazine 8 via the transport arm 33. .

In this way, the glass lens materials 2 on the magazine 8 are molded one after another.

In particular, in this embodiment, a quartz glass tube 46 is installed inside the electric furnace l for main heating the optical element 2, so that the temperature inside the electric furnace l is lower than that of the glass transition point.
Even if the temperature of the electric furnace 1 becomes 1-, for example, 600° C. or higher, the inner surface of the electric furnace 1 will not be oxidized and no oxides will be generated. As a result, the inside of the electric furnace 1 can always be maintained in a clean state, and the surface of the optical glass material during main heating can always be maintained in a clean state of 1 m. Therefore, the heating furnace 1 of this embodiment By using this method, it is possible to mold a glass lens having a good molding surface to which oxides do not adhere, and the occurrence of defective products can be significantly reduced.

(Second Embodiment) FIG. 6 shows a second embodiment of the electric furnace 1 according to the present invention. This embodiment is characterized by a cylindrical heat transfer member 47 in which a resistance wire 48 is embedded. The entire circumference of the heater section 45 is covered with a metal cover 49 to constitute the heater 45, and the inner wall surface of the heater section 45 (
This is because a quartz glass tube 46 is fitted onto the inner peripheral surface. The other configurations are the same as those shown in FIGS. 5(a) and 5(b), so the same members are given the same reference numerals and their explanations will be omitted. The configuration around the electric furnace 1 is the same as that in the first embodiment, so illustration and explanation will be omitted.

The above configuration also provides the same functions and effects as the first embodiment.

[Effects of the Invention] As described above, according to the present invention, an optical glass material can be formed into a shape in an electric furnace. -1-4, to obtain a glass lens that can be heated and softened in a state in which the inside of the heating furnace is always maintained in a clean state, and has a good molding surface without adhesion of oxides. I can do it. As a result, the number of defective molded products can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a molding apparatus equipped with an electric furnace according to the present invention, FIG. 2 is a schematic cross-sectional view to facilitate understanding of each configuration in FIG. 1, and FIG. 3(a). (b) is an explanatory diagram of the main parts of Figures 1 and 2, and Figure 4 (a)
, (b), (c), and (d) are perspective views illustrating the operating state of the main parts of FIGS. 1 and 2, and FIGS. An explanatory diagram showing an example, FIG. 6 is a second diagram of the present invention.
It is an explanatory diagram showing an example of. l... Electric furnace (main heating furnace) 2... Optical glass element (gob) 45... Heater section 46... Quartz glass tube 47... Heat transfer member 48... Resistance wire 49...・Cover patent applicant: Olympus Optical Industry Co., Ltd. Agent Takeshi Nara\2! λ -1゜Figure 4 (c)? l Figure 5 Figure 6

Claims (4)

[Claims] (1) An electric furnace for a glass forming apparatus for heating and softening an optical glass material to a moldable state, wherein the inner wall surface of the furnace is constructed of a quartz glass tube. (2) In the glass forming apparatus according to claim 1, wherein the quartz glass tube is integrally fixed to an inner wall surface of a cylindrical heat transfer member in which a resistance wire is embedded. Electric furnace. (3) The quartz glass tube is fitted onto the inner wall surface of a heater section that is constructed by covering a cylindrical heat transfer member in which a resistance wire is embedded with a cover. An electric furnace in the glass forming apparatus according to item 1. (4) The electric furnace in the glass forming apparatus according to claim 1, wherein the electric furnace equipped with the quartz glass on its inner wall surface is arranged adjacent to a preheating furnace.