JPH022816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a processing method for forming a glass mold of a desired shape on the end surface of a glass tube.

Electronic display devices that display characters and patterns by flashing indicator light bulbs are used to display traffic information, pollution information,
These electronic display devices are used in many fields such as recording information, but in order to improve display brightness, reduce power consumption, and make light bulbs smaller,
A display light bulb having a lens portion 2 at the tip of a bulb 1 as shown in the figure is used. Conventionally, the well-known blow molding method was used to form the lens portion 2 at the tip of the bulb 1, but when using this blow molding method, the outer surface shape of the lens portion 2 could be more accurately formed on the inner surface of the split mold. It can be molded based on
The inner shape of the lens portion 2 cannot be regulated, and the shape of the lens portion 2 may be distorted due to uneven distribution, viscosity, flow, etc. of the molten glass, or the optical axis of the lens may not accurately match the central axis of the bulb 1. The problem was that there were many errors and variations in the product.

The present invention provides a method for forming the end of a glass tube, which is free from the above-mentioned drawbacks and can be applied to the above-mentioned bulbs for display light bulbs, glass containers for mercury switches, and other various uses. Using a glass tube with an open end, the other end of the glass tube is heated and melted to close it, and then the molten end of the glass tube is placed in a female mold, and then the open end side is closed. By inserting a male mold into the glass tube and squeezing the molten tube end from inside and outside of the tube, a glass mold with the desired shape given by the male and female molds is accurately formed on the tube end surface without deformation or positional shift. This is a method for forming the ends of glass tubes.

Hereinafter, the method of the present invention will be specifically explained with reference to the drawings.

Figures 1 to 5 are display light bulbs (Figure 6)
A bulb 1 having a lens portion 2 at the tip used for
An example in which the present invention is applied to the production of In implementing the method of the present invention, first, a glass tube 3 of a predetermined length and thickness as shown in FIG. 1 is prepared. Thereafter, one tube end 4 of the glass tube 3 is melted by a heating device such as a burner, and the lower tube end 4 is closed with molten glass 5 as shown in FIG.

Next, while the molten glass 5 has yet to cool down and harden, the glass tube 3 is inserted into the female mold 6 as shown in FIG. 3 with the closed tube end 4 facing down.
A mold part 7 is formed at the inner bottom of the female mold 6 and is shaped to have the outer shape of the intended glass lens part 2 (FIG. 6). Therefore, the glass tube 3 inserted into the female mold 6 is placed with the molten glass 5 at the tip collected in the mold part 7, as shown in FIG. At this time, the glass tube 3 is fixed so as not to move by the inner circumferential wall surface of the female mold 6 and a fixing device (not shown) employed as necessary.

After the glass tube 3 is placed in the female mold 6 as described above, the male mold 9 that pairs with the female mold 6 is inserted from the upper open end 8 of the glass tube 3. The objective glass-shaped lens portion 2 (sixth
A mold portion 10 is formed having the inner surface shape shown in the figure. Therefore, the male mold 9 is connected to the open end 8 of the glass tube 3.
Insert the mold part 10 of the male mold 9 and the female mold 6
When the molten glass 5 is clamped from inside and outside the tube by the mold part 7 on the inner bottom surface of the glass tube, the lens part 2 provided by both mold parts 7 and 10 is pressure-molded on the end surface of the glass tube as shown in FIG.

After completing the pressure molding operation in this way, the male die 9 is moved back and the glass tube 3 is pulled out from the female die 6, and the end surface of the glass tube 4 is marked with the objective as shown in FIG. A glass barrel lens portion 2 is integrally formed. The lens portion 2 formed on the tube end surface of the glass tube 3 has an outer shape regulated by a female mold 6 and an inner shape regulated by a male mold 9, so that the positions of the male and female molds 6 and 9 forming a pair are regulated. As long as the alignment is accurate, the formed lens part 2 will not be deformed or the optical axis of the lens will not be deviated from the central axis of the glass tube 3, and the desired glass mold can be used. It can be formed precisely in the desired position.

The glass tube 3 shown in FIG. 5 obtained by the method of the present invention as described above is then subjected to predetermined steps to which a filament, a cap, etc. are attached, and is finally completed as a display light bulb shown in FIG. 6. Ru.

The above-mentioned embodiments show cases in which the method of the present invention is applied to the production of bulbs for display light bulbs.
The invention is not limited to this, and can be applied to various devices and devices. Further, the glass mold formed at the end of the glass tube is not limited to the one shown in the drawings, but can be formed into various shapes as shown in FIGS. 7 to 9, for example. Further, in the illustrated example, a glass tube 3 (FIG. 1) with both ends open is used, but in order to carry out the method of the present invention, it is sufficient that at least one tube end is open. . In addition, when carrying out the present invention, if a glass tube corresponding to the length of two parts to be manufactured is used and the central part of the glass tube is heated and cut, the tube can be closed by the molten glass 5 shown in FIG. It is possible to take out two glass tubes 3 at the same time in one heating and melting operation, and work efficiency can be improved.

Since the present invention has the structure and operation described above, a glass mold having a desired shape can be transformed into the tube end surface of a glass tube used in a bulb for an indicator light bulb, a glass container for a mercury switch, and various other devices. It can be formed accurately without causing any misalignment or misalignment, and has the remarkable effect of significantly improving the processing quality, manufacturing yield, and manufacturing efficiency of glass processed products.

[Brief explanation of drawings]

1 to 5 are process explanatory diagrams of the method of the present invention, in which FIG. 1 is a sectional view of a glass tube, FIG. 2 is a sectional view showing the closed end of the glass tube, and FIG. 3 is a sectional view of the glass tube. FIG. 4 is a cross-sectional view showing the state in which the glass tube is placed in the female mold, FIG. FIG. 6 is a partially cutaway side view of a display light bulb, and FIGS. 7 to 9 are cross-sectional views of a glass tube having a glass-shaped lens portion formed thereon. It is a sectional view showing an example. 1: Bulb, 2: Lens part (glass type), 3:
Glass tube, 4: tube end, 5: molten glass, 6: female mold, 7: mold part, 8: open end, 9: male mold, 10: mold part.

Claims (1)

[Claims] 1 Using a glass tube with at least one open end, melt the other end of the glass tube to close it, and then place the molten end of the glass tube in a female mold. Then, a male die is inserted into the glass tube from the open end side, and the tube end of the molten glass tube is squeezed from inside and outside the tube, and a glass die having a desired shape given by the male and female die is applied to the tube end surface. A method of forming the end of a glass tube, which is characterized by pressure forming.