JPH03187136A - Shrinkage-adhesion type implosion-proof band for face plate-panel of cathode-ray tube - Google Patents

Abstract

PURPOSE: To keep proper contact between both sides of a band and a panel by forming a partial inclination part surrounding the whole of the periphery of the band at an angle of θ. CONSTITUTION: A band 10 has a partial inclination part 14 formed by bending one side thereof along a direction off the flat surface of a main part at an angle of θ. Also, the inclination part 14 completely turns around the band 10 at a bent part 22. On the other hand, a taper is formed at an angle of β on the external surface 18 of the open part of a panel 16 at a position coupled to a funnel part, so as to ensure easy mold releasing at the molding process of an upper side wall 19 coupled to the panel 16. When the band 10 becomes cool, therefore, both sides 20 and 21 thereof come in close contact with the surfaces 18 and 19 of the panel 16. Also, the bent part 22 of the band 10 is aligned with a mold butt line 17 and the band 10 is positioned thereon. According to this construction, both sides 20 and 21 of the band 10 can be kept in proper contact with the sides of the panel 16.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an implosion prevention band for a cathode ray tube (CRT), and specifically an improved shrinkage-adhesive implosion prevention band. It's about the band.

[Background of the invention]

Since the interior of a cathode ray tube is evacuated to a very low pressure state, there is a possibility of implosion due to stress caused by atmospheric pressure acting on the entire surface of the tube. This problem,
The industry has countered this by providing CRTs with implosion prevention bands. This kind of band is CRT
It is used to apply compressive force to the sidewalls of the faceplate to redistribute some of the forces acting on the panel. By redistributing the forces on the panel, the tension at the corners of the faceplate is reduced and the potential for tube implosion is reduced. Furthermore, when an implosion occurs, this redistributed stress directs the scattered glass inside toward the back of the cabinet containing the tube, so that people who were near the imploded tube will be harmed. The chance of injury from broken glass is also significantly reduced.

Shrinkable 5tE implosion prevention bands are usually made by forming a steel strip into a loop with the same shape as the face plate to be protected, and connecting both ends of the loop at one side of the band. In this case, the band is made by connecting two strips of the same shape to each other on both sides of the loop. For both of the bands shown above, the circumference of the loop is slightly smaller than the circumference of the faceplate panel; the loop is heated to approximately 300°C to 500°C, and the coefficient of thermal expansion of the material determines the size of the loop. Extended for a sliding fit around the circumference. The band is.

As it cools, it contracts and tightly surrounds the panel,
Apply the required anti-implosion compression force to the panel sidewalls. This compressive force can be precisely controlled by controlling the yield point and thickness of the band, taking advantage of the known coefficient of thermal expansion of the band material.

The panel is molded by molding glass in a two-part mold. Therefore, there is a seam in the side wall of each panel, commonly called a mold abutment line, where the mold abutment lines meet. Furthermore, the side wall of the panel is thicker at the open end where it abuts the funnel than at the part where it joins the front surface of the panel. This angled sidewall improves the molding process and facilitates removal of the formed glass panel from the mold. To this end, the glass in front of the mold abutment line is offset to form a small angle with respect to the side wall portion where it joins the faceplate. Typically this angle is, for example, on the order of 5.5 degrees.

Best results with anti-implosion bands are achieved without one side of the band extending beyond the sidewalls at the corners of the panel.
This can be achieved when the implosion prevention band is placed as far forward as possible and covers the mold joining line. for that,
When using shrink-tight anti-implosion bands, ensure that the band extends flat against the angled gII wall of the panel, and that the sides of the band that extend beyond the mold abutment line always lie on the sides of the panel. For this reason, there is no contact and therefore it is not possible to obtain the best implosion protection and sufficient adhesion of the implosion protection band to the panel.

Both sides of the band are connected to the face plate to be protected.
There is a need for a shrink-tight implosion prevention band that reliably contacts the sides of the panel. This invention satisfies such demands.

[Summary of the invention]

In accordance with the present invention, shrinkage 5! for a cathode ray tube faceplate panel having a convex mold abutment line forming an angle β extending around the sidewall perimeter of the panel! The ER type implosion prevention band has a bent portion that completely surrounds its entire circumference and forms an angle θ. This angle θ lies above the mold abutment line of the panel sidewall.

This ensures that both sides of the implosion prevention band are in contact with the faceplate panel.

[Detailed description and examples]

FIG. 1 shows a contraction-tight implosion prevention band 10 which is a preferred embodiment of the present invention. This band 10 is
It has a rectangular shape with rounded corners 11. The long side dimension of the band 10 is indicated by A, and the short side dimension is indicated by B. For current standard cathode ray tube dimensions, the long side to short side ratio is 4:3.

Given such a ratio, the perimeter of the implosion prevention band should be 6 to 8 inches shorter than the perimeter of the panel to be protected, so each side should be 1.5 to 1.5 inches shorter than the side of the glass panel. 2.0mg
5 Made short. In addition, the inner diameter γ of the four corners 11 is equal to the outer diameter of the corner of the face plate f, and the two bands 10 are stretched during the heat treatment and are easily fitted to the face plate, so that the mold abutment line of the panel can be aligned with. During the cooling period, these corners are the first to rest on the panel sidewalls, and they are the first points of contact;
The band sits well and adheres to the panel, and the remaining portion of the band settles on the glass side wall.As the band cools, almost all the force is applied, causing the straight wall of the panel to bend. It is applied through this band to the transition region, ie, the transition region, to the corner region. thus,
The force is transmitted to the hexagons of the panel and to the faceplate at a rate proportional to the sine of the angle the band makes to the panel corner multiplied by the tension in the panel. The hexagonal corners of the band are fixed in place so they do not move, and the long sides of the band are initially automatically adjusted to balance the forces. Thus, most of the strain forces are concentrated in the transition zone of said corners, and forces exceeding the yield point of the band metal impart a controlled compressive force to the corner portions of the band, and through this band to the corners of the panel. . This compressive force counteracts the tension created in the corners of the faceplate by atmospheric pressure when the tube is evacuated.

Attachment lugs 12 are attached to the corners of the band IO and are used to attach the tube to the television receiver cabinet. The band IO is provided with fillets 13 at various positions along its length. This eyelet 13 is used in a television receiver. It is used to attach other components, such as electronic components, degaussing coils, and grounding straps.

FIG. 2 is a cross-sectional view of band IO taken along line 2--2 in FIG. The band 10 has an eccentric portion 14 that is offset from the band side in a direction away from the band plane by an angle θ. The tilted portion 14 has a band lO at the bent portion 22.
It extends completely around the area. The advantage of this tilted part 14 is that the fourth part showing a partial cross section of the panel to be protected is
You can clearly see this by looking at the diagram.

The manufacturing process for the faceplate panel 16 uses two mold pieces in which the glass is formed into the shape of the panel. Since this mold is a two-part type, panel 16
A mold abutting line 17 is formed completely surrounding the outer periphery of the mold and exactly at the point where the two molds abut. Further, the outer surface 18 of the opening portion where the panel 16 is connected to the funnel portion (not shown) is provided so as to form an angle β with respect to the upper side wall surface 19 that is connected to the face plate 1G. A typical value for the angle β is 5.5°; such an angle facilitates the manufacturing process, eg allowing the formed panel to be more easily removed from the mold.

Previously, when placing the shrink band around the panel 16, the band sat flat on the angled portion 18 of the panel 16, so that the upper sidewall surface 19 and the band lO
A small gap remained between them. According to this invention, the angle θ of the eccentric portion 14 provided in the band IO is 0.0.
5° to 3.5° larger, therefore.

When the band 10 cools down, the sides 20 and 21 of the band become
In close contact with surfaces 18 and 19 of panel 16, respectively. As band lO continues to cool, it contracts to conform to the shape of panel 16 such that the entire surface of the band is
firmly adheres to surfaces 18 and 19 of 6. Therefore, when the band is fitted onto the panel 16, the bent portion 22 of the band IO will be aligned with the mold abutment line 17 of the panel 16, and the band 10 will rest on the same line 17.

In FIG. 3, the inclined portion 10 extends over the entire length of the short side of the band 10, and as described above, completely covers the band lO.
is circling around. The ends of this band are overlapped and connected to each other by welding or any other method, as shown at 23. Band lO is! Connecting part 2 is shown in figure 81.
It can be formed by two strip members of the same shape as shown at 4.25, or alternatively by a single strip connected on one side as shown in FIG.

After the band 10 is connected into a loop, it is stretched by at least 1-1.5% to ensure that the band reaches its yield point during its cooling process.

This stretching operation can be easily accomplished by using a die at the corner 11 with a radius γ the same as the outside diameter of the faceplate corner to ensure that the band corner exhibits the required radius of curvature. The die inserted into this hexagon should be placed in a direction parallel to the diagonal of the face plate, and 1 to 1.5% of the above.
using a hydraulic jack or other equipment available in the art, by the distance necessary to obtain an extension of .

[Brief explanation of drawings]

FIG. 1 is a top view of an example of the contraction-adhesive implosion prevention band according to the present invention, FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1, and FIG. 3 is a side view of a preferable example of the band shown in FIG. , 4th
The figure is a partially cutaway sectional view of a side wall portion of a CRT faceplate panel. lO... Contraction-adhesive implosion prevention band, 14... Oblique I! , 1G...Faceplate panel, 17.
...Mold abutment line, 20.21...Both sides of the band. Procedural amendment (sealed) February 1991 Gohi Case Indication Patent Application No. 1992-325117 Name of the invention Relationship with the person who corrects shrinkage tight implosion prevention bands for face plates and panels of cathode ray tubes Case

Claims (1)

[Claims] (1) A shrink-tight implosion prevention band for a cathode ray tube faceplate panel having a convex molded abutment line extending around the sidewall and forming an angle β on the sidewall, the band comprising: The band has a tilted part located on one side of the band and extending over the entire circumference of the band in a direction offset from the band surface at an angle θ, and the angle θ is A contraction-adhesive implosion prevention band that is located on the joining line and configured to ensure that both sides of the band are in contact with the panel.