JPH07178758A - Method of forming television cabinet - Google Patents

Abstract

PURPOSE:To improve the productivity by a method wherein a molten resin is injected in a die, and then, a high pressure gas is injected to the vicinity of a holding part of a CRT to form a cavity in the vicinity of the CRT holding part, and at the same time, a secondary pressure is applied. CONSTITUTION:A molten resin is injected from an injection cylinder 22. Slightly after this injection, a gas in a gas press-feeding cylinder 25 is compressed by a piston 26, and is injected in a cavity of dies 19, 20 through a torpedo 28 and gas injection port 29. The feeding of the gas pressure is continued even after the completion of the pressurization for the molten resin. By this method, a cavity 32 is formed at a thicker part 16 in the vicinity of a gate 21 of a cabinet 10. Then, a secondary pressure is applied to the thicker part 16 through the cavity 32, and the pressure can be applied without loss to the inside at the corner part.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a CRT (cathode).
The present invention relates to a method for forming a housing of a television receiver having a holding portion for holding a ray tube (cathode ray tube), and more particularly to a method for forming a housing of a television receiver suitable for application to a bezel-integrated cabinet or bezel.

[0002]

2. Description of the Related Art A television receiver has a CRT housed in its cabinet.
The screen surface of will face the opening of the bezel. C
A mounting piece is provided at the corner portion of the RT, and the mounting piece is fixedly mounted to the holding portion of the cabinet or the bezel.

Since the weight of a large CRT increases, it is necessary to adopt a strong structure for the mounting portion of the CRT. Therefore, an independent bracket made of a molded body is prepared, and this bracket is attached to the corner portion of the cabinet. As another method, low-foam molding is performed to increase the wall thickness of the holding portion.

[0004]

If a molded bracket made of a separate member is used to mount a large CRT, not only the number of parts is increased, but also a means for fixing the bracket to the cabinet is provided. Needed and cost increased.

The low-foam molding is a method of injecting a resin containing a foaming agent together with a normal resin, but has a drawback that the molding cycle is long and the productivity of molding is deteriorated.

The present invention has been made in view of the above problems, and does not use a bracket formed of a separate member, does not require a long molding cycle such as low foam molding, and retains a CRT. It is an object of the present invention to provide a method of molding a casing of a television receiver in which the portion has sufficient strength.

[0007]

SUMMARY OF THE INVENTION The present invention provides a method of molding a casing having a holding portion for holding a CRT by injection molding of synthetic resin, wherein the molten resin for molding the casing is A method of injecting into a cavity in a mold for molding a housing and then injecting high-pressure gas into the cavity is used, and high-pressure gas is injected at least near the holding portion of the CRT.

In injection molding in which a molten resin is injected into a mold for molding, when a high-pressure gas is injected into the mold during injection of the molten resin, a cavity is formed inside the molded body by the gas. At the same time, it becomes possible to effectively apply the secondary pressure to the vicinity thereof. Use of the sympress molding method involving the injection of such a high-pressure gas has a local effect of preventing sink marks. Therefore, this is applied to a television receiver, particularly to a bezel integrated cabinet or bezel, and at the same time, a high pressure gas is injected at least in the vicinity of the holding portion of the CRT to apply a secondary pressure, whereby a television having a strong holding portion of the CRT. The John receiver housing is formed.

[0009]

[Function] At the same time as injecting the molten resin into the mold, after injecting the high pressure gas into the cavity, at least CR
By injecting high-pressure gas near the holding part of T,
A cavity is formed in the vicinity of the holding portion of the CRT, and it is possible to apply a secondary pressure to that portion, which allows the holding portion of the CRT having a strong structure to be integrally molded with the housing. Become. The CRT housed in the housing is held by the above holding unit.

[0010]

1 shows a television receiver cabinet 10 formed by a method according to an embodiment of the present invention. The cabinet 10 is integrally provided with a bezel on the front side thereof. It constitutes a cabinet with integrated basil. A rectangular opening 11 is formed in the bezel portion on the front surface side of the cabinet 10.
The CRT 12 is housed in the cabinet 10 so that the screen surface faces the screen 1.

The CRT 12 is provided with metal mounting pieces 13 on its four corner portions, and these mounting pieces 13 are formed on the four corner portions of the cabinet 10 as shown in FIGS. 2 and 3. It is adapted to be fixed to the retaining boss 14 by a tapping screw. The stop boss 14 is reinforced by ribs 15 and is integrally formed with the thick portions 16 of the four corners of the cabinet 10.

Such a bezel integrated type cabinet 10
As shown in FIGS. 3 and 4, the mold is molded by the dies 19, 20 by the sympress molding method. As shown in FIG. 4, a die portion of the injection cylinder 22 is connected to the gate 21 portion of the molds 19 and 20 for injecting the resin. A screw 23 is held in the injection cylinder 22, and the molten resin 24 is extruded by the screw 23.

Further, a gas press-fitting cylinder 25 is connected to the injection cylinder 22. A piston 26 is slidably held in the gas press-fit cylinder 25. A gas supply source is further connected to the cylinder 26 via a valve 27. In addition, the gas injection cylinder 2
The discharge side of 5 is connected to the torpedo 28 held at the discharge port of the injection cylinder 22. A gas injection port 29 is attached to the tip end side of the torpedo 28. The mold for molding the cabinet 10 is provided with four gates 21 at the corners thereof as shown in FIGS. 2 and 3.

In the structure as described above, the molten resin 24 is injected from the injection cylinder 22 shown in FIG. 4 through the gate 21 into the cavities of the molds 19 and 20. Then, slightly later than the injection of the molten resin 24, the gas in the gas injection cylinder 25 is compressed by the piston 26, and this gas is injected into the cavity through the torpedo 28 and the gas injection port 29. The supply of the gas pressure by the cylinder 25 continues even after the pressurization of the molten resin 24 is completed.

Cabinet 1 molded in this way
A space 32 is formed by the injection gas in the thick portion 16 having a particularly large thickness in the vicinity of the zero gate 21. Then, since the secondary pressure is applied to the thick wall portion 16 through the space 32 by the gas pressure, a pressure without loss is applied to the inside of the corner portion of the cabinet 10.

In the cabinet formed by such sympress molding, since the secondary pressure is applied to the thick portion 16 at the corner portion by the gas, sink marks can be prevented. The thick stop boss 14 can be formed by the gas pressure. That is, conventionally, only the stop boss for screwing the tapping screw having a diameter of 5 mm could be formed, but by applying the secondary pressure by the gas, the boss 14 for screwing the tapping screw having a diameter of 7 mm can be formed. become.

By forming a space 32 in the thick wall portion 16 of the corner and applying a secondary pressure through this space 32, the strength of the corner portion is improved, which causes a heavy weight through the stop boss 14. It becomes possible to securely hold the CRT 12. Therefore, it is possible to design the thickness of the molded article as thick as that of an ordinary molded article and to firmly design the vicinity of the holding portion 14 of the CRT 12. In addition, by adopting such sympress molding, the cycle time does not become long as in low-foam molding, and a large CRT is used.
Cabinet 10 for directly fixing 12 to its holding portion 14
Can be efficiently molded.

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to the above embodiment,
Various modifications can be made based on the technical idea of the present invention.
For example, although the above embodiment relates to a bezel integrated type cabinet, the present invention is also applicable to a bezel having a holding portion for a CRT.

[0019]

As described above, according to the present invention, in a method in which a housing of a television receiver is injection-molded, molten resin is injected into a mold cavity for molding the housing, and thereafter, In addition, the method of injecting high-pressure gas into the cavity is used, and the high-pressure gas is injected at least near the holding portion of the CRT.

Therefore, according to the present invention, the high-pressure gas injected into the cavity forms a cavity particularly near the holding portion of the CRT, and the cavity 2 is formed through the cavity.
The secondary pressure can be applied, and the holding portion of the CRT can have a strong structure. Moreover, it is possible to mold a housing having a plate thickness of the same level as a molded product having a normal plate thickness in a short molding cycle.

[Brief description of drawings]

FIG. 1 is an external perspective view showing attachment of a CRT to a molded cabinet.

FIG. 2 is a vertical sectional view of a cabinet of a television receiver.

FIG. 3 is a cross-sectional view of the cabinet in the portion where the holding portion of the CRT is formed.

FIG. 4 is a longitudinal sectional view of a main part of a molten resin injection device.

[Explanation of symbols]

 10 Cabinet 11 Opening 12 CRT 13 Mounting Piece 14 Stop Boss 15 Rib 16 Thick Part 19, 20 Mold 21 Gate 22 Injection Cylinder 23 Screw 24 Molten Resin 25 Gas Injection Cylinder 26 Piston 27 Valve 28 Torpedo 29 Gas Injection Port 32 Space

Claims (1)

[Claims] 1. A method in which a housing having a holding portion for holding a CRT is molded by injection molding of synthetic resin, wherein the molten resin is injected into a cavity in a mold for molding the housing, After that, a method of injecting a high-pressure gas into the cavity is used, and the high-pressure gas is injected at least in the vicinity of the holding portion of the CRT.