JP2001294435A - Forming method for cathode ray tube panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming device for cathode ray tube panels which is capable of making the cooling temperature distribution of a forming surface of a plunger uniform and effectively preventing the sticking of glass to the plunger. SOLUTION: Cooling means 6 which blow off cooling air toward four corner parts 1b of the plunger forming surface 1a are installed between the plunger 1 existing in an upward resetting position and a shell die 4 assembled to a bottom die 3 operatively forward and backward by means of a forward and backward operating means 7. The cooling means 6 are controlled by means of the forward and backward operating means 7 in such a manner that the cooling means are advanced to the lower part of the plunger 1, that the cooling are is blown off and that the cooling means are retreated from the lower part of the plunger 1 before the plunger 1 moves downward in association with the forward and backward operation of the plunger 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube panel molding apparatus.

[0002]

2. Description of the Related Art Conventionally, a cathode ray tube panel supplies a predetermined amount of a molten glass lump (gob) into a mold combining a bottom mold and a shell mold, and descends a plunger disposed above the mold. It is manufactured by moving the gob in the mold with a plunger and press-molding it into a predetermined shape. This type of molding apparatus includes a plurality of dies (for example, 11
Are arranged at equal intervals around the rotary table.
With the intermittent rotation of the rotary table, the molds are sequentially turned into gob supply stations, press stations, cooling stations,
It is sent to the product removal station. In the gob supply station, the molten glass is extruded from the supply unit of the glass melting furnace and cut, and a predetermined amount of gob is supplied into the mold. In the press station, the plunger is moved downward each time the mold to which the gob is supplied arrives,
The gob in the mold is pressed into a predetermined shape. The CRT panel pressed into a predetermined shape in the mold is cooled through a predetermined cooling station, sent to a product removal station, and removed from the mold.

[0003]

The plunger is continuously press-molded to a gob in a mold which is sequentially sent to a press station. In press molding, a plunger for a CRT panel to be molded is used. In order to stabilize the shape, the pressed state of the plunger is held for a few seconds at the lower end position where the gob is pressed. Thus, the plunger is exposed to severe high temperature conditions,
Conventionally, the plunger is cooled by cooling the inside of the plunger with water or air. However, it is difficult to make the molding surface of the plunger have a uniform temperature distribution over the entire surface. That is, the molding surface of the plunger for molding the inner surface of the substantially box-shaped CRT panel has four bottom surfaces for molding the inner surface of the face portion of the CRT panel and four side surfaces for molding the inner surface of the skirt portion of the CRT panel. In the transition region from the bottom surface to the side surface of the molding surface, that is, near the boundary region between the bottom surface and the side surface, the molding surface receives heat from two directions of the bottom surface and the side surface. In particular, at the four corners of the molding surface,
Since heat is received from three directions of the bottom part and the two side parts constituting the corner part, the temperature is likely to be high compared to other parts. In addition, increasing the cooling effect to cool such a high-temperature region will cause the temperature of other parts to be too low, so that an uneven temperature distribution of the plunger will still occur. In particular, as shown in FIG. 1D, among projection tubes, when projecting a projection type CRT panel 9 in which the face portion 9a of the panel has a convex shape inward of the panel, the four corners of the plunger are Since it has a shape protruding from the center, the cooling action from the inside of the plunger is not sufficiently achieved, and the temperature rise at the four corners becomes remarkable.

Conventionally, glass is burnt in flakes at the four corners of the plunger, and the glass flakes burned on the plunger are transferred to the inner surface of the CRT panel to be molded, causing surface defects of the CRT panel. I was

Conventionally, an operator always visually observes a molding surface of a plunger, and when a seizure of glass occurs on the molding surface of the plunger, it is necessary to sharpen the glass with sandpaper each time. However, it was necessary to replace the plunger at an early stage, causing problems in productivity and workability.

Accordingly, an object of the present invention is to provide a molding apparatus for a CRT panel which can make the cooling temperature distribution on the molding surface of the plunger uniform and can effectively prevent seizing of glass on the plunger. .

[0007]

In order to achieve the above object, a CRT panel molding apparatus according to the present invention comprises a mold having a combination of a bottom mold and a shell mold, and a predetermined amount of molten glass block (gob). ) Is supplied, and the plunger disposed above the mold is moved downward to press the gob in the mold into a predetermined shape with the plunger. Cooling means for blowing cooling air toward the four corners of the plunger molding surface is provided between the shell mold combined with the mold so as to be able to advance and retreat by the advance and retreat operation means, and the cooling means is provided on the plunger. In connection with the ascent / return operation, the advancing / retreating operation is performed so as to enter the lower portion of the plunger to blow out cooling air and to retreat from the lower portion of the plunger before the plunger moves downward. It is obtained by controlled via.

[0008] With the above configuration, the plunger can be cooled without hindering the press molding operation of the plunger. In addition, cooling air is blown to the four corners of the plunger molding surface, which is a high-temperature portion, so that the plunger molding surface can be cooled. Since the high temperature part is cooled without partial cooling, the temperature distribution on the entire plunger molding surface can be uniformed,
Seizure of the glass piece on the plunger can be effectively prevented.

Further, in the apparatus for molding a cathode ray tube panel of the present invention, the cooling means has a nozzle outlet capable of blowing cooling air from the lower inside of the four corners of the plunger molding surface toward the four corners. Features. With this configuration, the cooling air can be blown only to the four corners, which are the high temperature portions of the plunger, to cool the center portion of the plunger molding surface while reliably discharging the cooling air outward so as not to hit the plunger molding surface. Only the high-temperature portion of the plunger can be effectively cooled in a short time, and the uniformity of the temperature distribution of the entire plunger mold can be further ensured.

[0010]

Embodiments of the present invention will be described below with reference to embodiments shown in the drawings. 1A is a schematic side view of a main part of a cathode ray tube panel forming apparatus equipped with the present invention, FIG. 1B is a schematic longitudinal sectional side view of a cooling unit, FIG. 1C is a schematic plan view of a cooling unit, and FIG. 1 is a schematic sectional view of a projection type cathode ray tube panel.

In FIG. 1A, 1 is a plunger,
2 is a lifting means, 3 is a bottom mold, 4 is a shell mold,
Reference numeral 5 denotes a rotary table mechanism, 6 denotes a cooling unit, 7 denotes an advancing / retracting operation unit, and 8 denotes a gob.

The plunger 1 is installed in a press station of a cathode ray tube panel molding apparatus via a lifting / lowering means 2 such as an air cylinder so that the plunger 1 can be moved up and down. For example, in the case of a projection type cathode ray tube panel 9 as shown in FIG. 1 (D), the central portion of the bottom surface has an upwardly convex spherical shape.

The bottom mold 3 is for forming the face portion of the cathode ray tube panel and the skirt portion following it in cooperation with the plunger 1, and is arranged around the rotary table mechanism 5 at equal intervals. The intermittent rotation operation 5 allows the gob supply station, the press station, the cooling station, and the product take-out station to circulate.

The shell mold 4 is combined with the bottom mold 3 to mold the sealing edge surface of the skirt of the CRT panel. After the cooling station, the shell mold 4 is removed from the bottom mold 3 and the product is removed. After passing the unloading station, it is returned onto the bottom mold 3 and assembled.

The cooling means 6 is disposed between the molding surface of the plunger 1 at the return position and the shell mold 4 combined with the bottom mold 3 which has reached the press station. (B) As shown in (C), a flat hollow rectangular box-shaped tank 6a conforming to the bottom contour of the molding surface 1a of the plunger 1, and openings are formed at the four corners of the tank 6a, and the four corners of the plunger 1 are formed. A nozzle outlet 6b for blowing cooling air toward the corner portion 1b, and is connected to a suitable cooling air supply source (not shown) such as a compressor via a flexible pipe 6c. A regulating valve and a supply control valve are installed. As shown in FIGS. 1B and 1C, the nozzle outlets 6b of the cooling means 6 are provided at the four corners of the rectangular box-shaped tank 6a in the downward direction at the four corners 1b of the molding surface 1a of the plunger 1. It is formed so that cooling air can be ejected from the inside toward the four corners 1b.

The reciprocating means 7 of the cooling means 6 is constituted by an air cylinder or the like. The reciprocating means 7 is combined with the plunger 1 at the ascending / returning position and the bottom mold 3 which has reached the press station. The cooling means 6 is attached to the shell mold 4 so that the cooling means 6 can move forward and backward. Then, the cooling means 6 is caused to enter the lower part of the plunger 1 in association with the ascent / return operation of the plunger 1 to blow out the cooling air through the advancing / retreating operation means 7 so that the plunger 1 is moved before the plunger 1 descends. Control to retreat from the lower part.

The configuration of the embodiment of the device of the present invention is as follows.
As described above, the operation will be described next. After the plunger 1 press-molds the gob in the bottom mold 3,
Since it waits at the ascent / return position until it descends for the next press, at this time, the cooling means 6 is moved forward by the reciprocating operation means 7 to move to the position facing the molding surface 1a of the plunger 1. Then, cooling air is jetted from the nozzle outlet 6b to cool the four corners 1b, which are the high-temperature portions of the molding surface 1a of the plunger 1, so that the cooling temperature distribution over the entire molding surface 1a of the plunger 1 is uniform. To After the temperature distribution becomes uniform, the cooling means 6 is retreated in the retreating direction by the reciprocating operation means 7 and retreats from the facing position of the plunger 1.

In the step of press-molding the CRT panel, the temperature of the plunger 1 needs to be maintained within a certain temperature range, and the range is limited to an extremely narrow range of several tens of degrees Celsius. Therefore, it is important to raise and lower the overall temperature of the plunger 1 and to make the temperature uniform.

Therefore, by cooling the plunger 1 by the apparatus of the present invention, the temperature of only the high-temperature portion of the molding surface 1a of the plunger 1 can be lowered by 30 to 50 ° C., and the temperature distribution of the entire molding surface of the plunger 1 can be made uniform. As a result, in the high-temperature portion of the molding surface 1a of the plunger 1, it is possible to prevent glass flakes from adhering to the plunger 1 due to seizure of the glass.

[0020]

According to the first aspect of the present invention, the plunger can be cooled without hindering the press-molding operation of the plunger, and the cooling air is blown to the four corners of the plunger molding surface, which is a high-temperature portion. Since the high temperature part is cooled without cooling other parts of the molding surface, the temperature distribution on the entire plunger molding surface can be made uniform, and the sticking of the glass flakes to the plunger mold can be effectively prevented. can do.

According to the second aspect of the present invention, the cooling air is discharged to the center of the plunger molding surface without fail so that the cooling air does not hit the center of the plunger only at the four corners, which are the high temperature portions of the plunger. Of the plunger, it is possible to effectively cool only the high-temperature portion of the plunger in a short time, and the uniformity of the temperature distribution over the entire molding surface of the plunger can be further ensured.

[Brief description of the drawings]

1A is a schematic side view of a main part of a cathode ray tube panel molding apparatus equipped with the present invention, FIG. 1B is a schematic vertical sectional side view of a cooling means, FIG. 1C is a schematic plan view of a cooling means, FIG. () Is a schematic sectional view of a projection type cathode ray tube panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plunger 2 Elevating means 3 Bottom mold 4 Shell mold 6 Cooling means 6a Tank 6b Nozzle outlet 7 Advance / retreat operation means

Claims (2)

[Claims] 1. A predetermined amount of molten glass lump (gob) is supplied into a mold in which a bottom mold and a shell mold are combined, and a plunger disposed above the mold is moved downward to move the inside of the mold. In a CRT panel molding device that press-molds a gob into a predetermined shape with a plunger, between the plunger at the ascending / returning position and the shell mold combined with the bottom mold, facing the four corners of the plunger molding surface Cooling means for blowing out cooling air by means of an advancing / retreating means so as to be able to advance and retreat, and the cooling means,
In connection with the plunger's ascent / return operation, cooling air is blown out by entering into the lower part of the plunger and controlled via the above-mentioned reciprocating operation means so as to retreat from the lower part of the plunger before the plunger moves down. CRT panel molding equipment. 2. The cathode ray tube panel according to claim 1, wherein the cooling means has a nozzle outlet capable of blowing cooling air from below the four corners of the plunger molding surface toward the four corners. Molding equipment.