JPH0214837A - Hollow glass, production of hollow glass and mold of pressed gob - Google Patents

Abstract

PURPOSE:To reduce a ratio of change of thickness distribution along the whole length of barrel part in molding hollow glass by setting protruded part at the central part on the under surface of pressed gob, thickening the central part and cutting off temperature reduction at the central part. CONSTITUTION:In producing bottomed cylindrical hollow glass such as cup by rotary blow molding by machine, glass lump 8 in a molten state is placed on a dented part 24 of a lower mold 7 having closed space 25 as a heat insulating part at the lower side of central part and the glass lump is pressed by an upper mold 6. A pressed gob 20 having a protruded part 29 at the lower side of central part, the gob is taken out from the mol, the peripheral part thereof is placed on a peripheral part of central hole of a working ring 38, the ring 38 is rotated and the gob 20 is hung by dead weight thereof in a mold 39 of blow machine. Then air 44 is sprayed upon the gob 20 to give a parison 45 with an outer form and an inner form close to final shapes. Consequently, the gob 20 is maintained at high temperature at the central part and elongation of the parison can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to hollow glass having a cylindrical shape with a bottom such as a cup formed by mechanical blow molding, particularly hollow glass having a shape similar to artificial blow molding, The present invention relates to a manufacturing method thereof and a mold for forming a press gob for hollow glass.

[Conventional technology]

In general, hollow glass products such as pots that have a cylindrical shape with a bottom (
When manufacturing a glass tip (hereinafter referred to as a glass tip), two methods are widely used: artificial blow molding and mechanical blow molding. In the former method, a worker attaches a molten glass gob to the tip of a blowing rod and blows into the glass gob through the rod while rotating the blowing rod to produce a glass tip in a predetermined shape, as shown in Figure 8. As shown in FIG. 2, the glass tip 4 has a characteristic that the thickness distribution of the body portion 1 gradually increases continuously over the entire length from the open end 2 to the bottom portion 3 at a small rate of change, so that a well-shaped glass tip 4 can be obtained. On the other hand, in the latter case, a molten glass gob 8 is pressed by a press gob mold 5 consisting of an upper mold (suction head) 6 and a lower mold (press head) 7 shown in FIG. A gob (hereinafter referred to as a press gob) 9 (see Fig. 10) is placed on a working ring and allowed to hang down into the blow machine mold by its own weight, and then air is blown onto the press gob to perform the blow machine molding. By bringing the parison into close contact with the inner surface of the mold, a parison having an outer and inner shape close to the final shape is formed by rotating the parison. In this case, the press gob 9 has a disc-shaped convex portion 10 having a thickness tl (example 4 crane) smaller than the wall thickness t of the press gob 9 (example 10 fin) on the lower side of the central portion corresponding to the bottom of the glass tip to be manufactured. However, as shown in FIG. 11, a press gob 9 having an increased overall thickness for the purpose of attaching a bottom part as a glass comb may also be used.

[Problem to be solved by the invention]

By the way, in the glass tip 4 manufactured by the artificial blow molding method, as shown in FIG. Although these products are increasing in number and are beautiful in shape, they are handmade and have low productivity, require skill, and are expensive to obtain a certain level of quality.

On the other hand, when using the mechanical blow molding method, when the press gob 9 shown in FIG. There was a problem in that a discontinuous portion 11 where the rate of change in wall thickness changes occurs near 1/2, and the wall thickness increases rapidly toward the bottom 3. Similarly, the first
When the press gob 9 shown in FIG. 1 is used, as shown in FIG. This tends to result in a wall thickness distribution where the wall thickness increases rapidly.

Such a discontinuous portion 11 changes the direction of refraction of light, resulting in a glaring streak.

In this way, if the conventional mechanical blow molding method attempts to bring the wall thickness distribution of the body 1 of the glass top 13 closer to that of the glass top 4 produced by the artificial blow molding method, it is difficult to produce products with particularly thick bottom portions 3. When making this, there was a drawback that the wall thickness of the body part 1 became thicker than necessary.

Therefore, we focused on why mechanical blow molding cannot produce the same glass tops as artificial blow molding, and found that when forming the press gob 9, mechanical blow molding cannot produce the same glass tip. It has been found that this is due to the fact that the temperature of the thick part is taken away by the mold 5 and falls below a predetermined temperature, which causes poor elongation of the parison during mechanical blow molding.

Therefore, the present invention solves the above-mentioned problems,
The object of the present invention is to provide a hollow glass having a simple configuration and a shape similar to an artificially blown product, a method for manufacturing the same, and a mold for forming a press gob for the hollow glass.

[Means to solve the problem]

The present invention has been made to achieve the above object, and a first aspect of the present invention is to provide a convex portion at the center of the lower surface of the press gob when forming the hollow glass, to thicken the wall thickness of the center portion, and to increase the thickness of the central portion. By blocking the temperature drop in the center, the body is formed so that the thickness distribution of the body gradually increases continuously over the entire length from the open end to the bottom at a small rate of change.

The second invention is to supply a molten glass gob to a press gob mold consisting of an upper mold and a lower mold having a heat insulating part on the lower side of the center to form a disc-shaped press gob having a convex part at the center of the lower surface. The press gob is removed from the press gob mold, its peripheral edge is placed on the peripheral edge of the center hole of the working ring, and the working ring is rotated so that the press gob hangs down into the blow machine mold due to its own weight. The press gob is then blown with air to form a parison having an outer and inner shape close to the final shape.

In a third aspect of the invention, a mold for forming a press gob for hollow glass is composed of an upper mold and a lower mold, and a heat insulating part is provided below the center of the lower mold.

[Effect]

In the present invention, when the press gob is made thicker at the center of the press gob and the temperature drop in the center is blocked, the elongation of the center is good during the parison forming process, and the thickness distribution of the body becomes more open. It increases continuously with a gradually smaller rate of change over the entire length from the end to the bottom.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of a mold for press-forming a press gob for hollow glass used to produce hollow glass according to the present invention, and FIG. 2 is a cross-sectional view of a press gob formed by the same mold. FIG. In these figures, a mold 5 for forming a press gob 20 for hollow glass includes an upper mold 6 and a lower mold 7, and a disc-shaped recess for the press gob 20 is provided in the center of the lower surface of the upper mold 6. 21 is recessed, and a plurality of small vacuum holes 22 are concentrically formed so as to open at the upper peripheral edge of the upper die 6 and the bottom peripheral edge of the recess 21. On the other hand, a recess 24 is formed in the center of the upper surface of the lower mold 7 and a recess 26 is formed in the center of the lower surface. As a result, a sealed space 25 is formed as a heat insulating section. therefore,
The sealed space 25 constitutes a heat insulating space, and prevents a drop in temperature at the center of the press gob 20 when the glass gob 8 is pressed with the mold 5 to form the press gob 20 shown in FIG. If the size of the sealed space 25 is too small or too large, the thickness distribution of the body of the glass tip will not improve. That is, if it is too small, the heat insulating effect will be poor and it will get too cold, and as in the conventional case, a discontinuous part 11 in the wall thickness will occur in the middle of the body shown in FIGS. 12 and 13, causing a change in the wall thickness distribution. On the other hand, if it is too large, the press gob 20 hangs down too much and only the bottom 3 of the glass tip becomes thick, making it impossible to obtain a glass tip with a wall thickness similar to that of an artificially blown glass tip. Therefore, the sealed space 25 is determined by the size, height, wall thickness, etc. of the product to be manufactured, and its outer diameter is determined by the fourth
8 of the hole diameter of the center hole 41 of the working ring 38 shown in the figure.
It is desirable to set it within the range of 0% to 97%.

In this case, in this embodiment, the heat insulating part is a disk-shaped sealed space 25, but this is not limited to this, and various changes can be made depending on the degree and range of the heat insulating effect required. For example, as shown in FIG. In addition, a protrusion 30 is integrally provided in the center of the upper surface of the cover 27 to form an annular sealed space 25A (Figure a), and a protrusion 31 is integrally provided in the center of the bottom of the recess 26 of the lower mold 7. to create an annular closed space 25A (Figure b), or alternatively to create a lower mold 7.
The bottom surface of the recess 26 may be a convex curved surface 33 having an appropriate curvature, and an annular sealed space 25B with a reduced thickness at the center (Figure 0) may be formed.
25A and 25B may be filled with a heat insulating material as necessary.

A hole diameter of 0 is provided at the periphery of the bottom of the deepest part of the recess 24 of the lower die 7.
．． A plurality of air vent holes 36 of about 2 to 0.5 W are formed concentrically, for example, six, and their inner ends communicate with the inner ends of communication holes 37 formed radially on the circumferential surface of the lower mold 7. are doing.

Note that the cover 27 has a plurality of hexagon socket head bolts 28.
is fixed to the lower surface of the lower die 7 by.

The press gob 20 formed by the mold 5 is the second
As shown in the figure, it is disc-shaped, and the press gob 2 is attached to the center of the lower surface.
Thickness (7
A truncated cone-shaped convex portion 29 having a shape similar to that of a crane is provided. The convex portion 29 increases the volume of the press gob 20 and keeps the temperature of the central portion high. If the thickness of the center part of the press gob 20 is thick, unlike the case of press forming the press gob 9 shown in FIG. The air is allowed to escape to the side of the lower die 7 through the communication hole 37 through the air vent hole 36 .

Next, to explain the manufacturing process of the glass gob, first, a molten glass gob 8 is placed in the recess 24 of the lower die 7, and this is pressed with the upper die 6, thereby forming the press gob 20 shown in FIG. .

After pressing the glass gob 8 with the upper mold 6 for a predetermined time, the upper mold 6 is raised. At this time, the vacuum pump (
The press gob 20 that has been press-molded is sucked and held within the recess 21 of the upper die 6 and transferred to the next parison forming process. The parison forming process is a process of rotating and blowing the press gob 20 to form it into a shape close to the final product shape.As shown in FIG. It includes a die 39 and a blow head 40, the peripheral edge 20a of the press gob 20 is placed on the upper surface of the peripheral edge of the center hole 41 of the working ring 38, and the blow head 40 descends over this peripheral edge 2°a. The blow head 40 and the working ring 38 are held together. A few seconds after the press gob 20 is placed, the working ring 38 receives a rotational transmission from a drive motor (not shown) and rotates at a constant speed at a predetermined rotational speed until just before the parison is taken out.

The blow machine mold 39 has first and second molds 39A and 39B formed into two parts on the left and right, and a bottom mold 39C,
One end of the first and second molds 39A and 39B are connected with a hinge so that they can be opened and closed, and is provided with a recess 42 that is equal to the external shape and height of the final product. In order to facilitate the rotation of the parison, paste malt (not shown) is applied by applying and baking cork, and water is further sprayed onto the parison. The bottom mold 39C is vertically movable, is not subjected to base molding, and is rotated at a constant speed during parison molding.

Press gob 2 placed on the working ring 38
Due to its own weight, the center portion of the working ring 38 gradually hangs down into the recess 42 of the blow machine mold 39 through the center hole 41 of the working ring 38, and this hanging portion forms a parison 45. FIG. 5 shows this state. At this time, since the above-mentioned working ring 38 is rotating, the parison 45 also rotates and gradually hangs down. An air injection hole 43 provided at the center of the blow head 40
By blowing more compressed air 44 toward the parison 45 for a predetermined period of time and bringing the parison 45 into close contact with the inner surface of the recess 42 of the mold 39, the final product has an outer shape and an inner shape as shown in FIG. The parison 45 is turned and blow molded. In this case, when the press gob 20 placed on the working ring 38 hangs down, the temperature at the center is kept high due to the heat insulation effect of the closed space 25 of the press gob mold 5, so that the press gob 20 elongates as shown in FIG. The thickness of the body of the final product changes continuously over the entire length at a small rate of change, improving the thickness distribution in mechanical blow molding.

Therefore, there are no discontinuous parts in the wall thickness,
Further, this change in thickness distribution is approximately equal to the thickness distribution of the glass tip 4 formed by the artificial blow molding method shown in FIG.

When the parison 45 is turned and blow-molded, the working ring 38 stops and the mold 39 is opened, at the same time the blow head 40 is raised, and then the parison 45 is moved to the peripheral edge 2.
0a is removed from the working ring 38, leaving 0a;
In the next step, the unnecessary opening end portion (moil portion) 46 of the parison 45 is cut and removed by appropriate means (48 is a cutting line), thereby obtaining the glass tip 50 shown in FIG.
This is very similar to the glass tip 4 shown in FIG. 8 which is made by artificial blow molding.

〔Effect of the invention〕

As explained above, the hollow glass according to the present invention improves the elongation of the parison by maintaining a high temperature in the center of the press gob, and continuously changes the wall thickness distribution of the body at a small rate of change over the entire length. As a result, a hollow glass whose inner and outer shapes are similar to the inner and outer shapes of hollow glass produced by the artificial blowing method can be obtained despite the mechanical blowing method.
The effect is great. In addition, in the present invention, it is only necessary to provide a heat insulating section under the center of the lower die of the press gob mold and to increase the thickness of the center part of the press gob, so there is no need to significantly change the conventional manufacturing process. Existing equipment can be used as is, and it is also easy to provide a heat insulating section on the conventionally used lower mold.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of a press gob mold according to the present invention, Fig. 2 is a front view of a press gob press-molded by the same mold, and Figs. 3 (a), (b), and (c). 4 to 6 are cross-sectional views showing other examples of the heat insulating part, respectively.
The figure is a diagram for explaining the parison molding process, Figure 7 is a sectional view of a glass tip manufactured by the present invention, Figure 8 is a sectional view of a glass tip formed by artificial blow molding, and Figure 9 is a conventional one. Cross-sectional view of the press gob mold,
Figures 10 and 11 are front views of press gobs press-formed for glass tip, and Figures 12 and 13 are glass blow-molded glass using the press gobs shown in Figures 10 and 11, respectively. It is a sectional view of kelp. 1...Body part, 2...Opening end, 3...Bottom part, 4...
・Glass tip, 5...Press gob mold, 6...
Upper mold, 7... Lower mold, 8... Glass lump, 9
... Press gob, 11 ... Discontinuous part, 20
... Press gob, 24 ... Recess, 25 ... Sealed space, 26 ... Recess, 27 ... Cover, 29 ... Protrusion, 38 ... Working ring, 39 ... Blow machine Molding mold, 40... blow head, 45... parison, 50... glass kelp.

Claims (3)

[Claims] (1) By providing a convex portion at the center of the lower surface of the press gob, increasing the wall thickness at the center and blocking a drop in temperature at the center, the wall thickness distribution of the body can be adjusted over the entire length from the opening end to the bottom. Hollow glass characterized by being formed so as to increase continuously at a gradually small rate of change. (2) A molten glass gob is supplied to a press gob mold consisting of an upper mold and a lower mold having a heat insulating part on the lower center side to form a press gob having a convex part at the center of the lower surface. The press gob is removed from the mold, its peripheral edge is placed on the peripheral edge of the center hole of the working ring, the working ring is rotated, the press gob hangs down into the blow machine mold by its own weight, and the air is then forced into the blow machine mold. A method for manufacturing hollow glass, characterized in that a parison having an outer and inner shape close to the final shape is formed by blowing onto a press gob. (3) A press gob mold consisting of an upper mold and a lower mold, characterized in that a heat insulating part is provided below the center of the lower mold.