JPH0479463B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a reinforced cathode ray tube, and more particularly to its reinforcement structure.

[Technical background of the invention and its problems]

Cathode ray tubes are usually formed from an envelope consisting of a substantially rectangular panel having a fluorescent surface on its inner surface. When the inside of this envelope is evacuated to a high vacuum, the pressure difference causes the portion of the panel with a fluorescent surface to move inward to the envelope, and the substantially rectangular side wall portion of the panel to move outward from the envelope. A strong stress is applied. Therefore, implosion can easily occur due to an external impact or a slight defect. To prevent this, the most effective means is to use an explosion-proof method in which the side walls of the panel are tightened and reinforced with metal bands. Among these explosion-proof methods, the explosion-proof method in which one end of the metal strip is mechanically pulled and tightened cannot obtain a uniform tightening force due to the frictional force between the metal strip and the side wall of the panel, and the two ends of the metal strip overlap each other. Since the panel is joined by welding or the like, there is a gap between the panel side wall and the panel side wall, and there is also the problem that a uniform tightening force cannot be obtained. On the other hand, the so-called shrink-fitting method, in which a metal band is previously formed into an annular shape, heated and expanded, fitted to the side wall of the panel, and cooled and shrunk, has the advantage that a relatively uniform tightening force can be obtained. Generally, when a metal strip is used within its elastic limit, the elongation of the metal strip is proportional to the tightening stress of the metal strip. On the other hand, when used beyond the elastic limit, the change in tightening stress is small compared to the elongation of the metal strip. Therefore, in the shrink-fitting method, the inner diameter of the annular metal band is formed to be slightly shorter than the outer diameter of the panel side wall, and the metal band is used at an elongation rate that exceeds its elastic limit, so that the tightening stress can be adjusted as the amount of elongation changes. Tighten so that there are fewer changes. In addition, when forming a metal band into a ring shape, if parts of both ends of the metal band are overlapped and fixed by welding, the tightening force will be uneven as in the mechanical tightening method, as shown in Figures 1 and 2. It is preferable to have a structure in which both ends of the metal strip 1 are brought together at the joint portion 2 and fixed by welding via the auxiliary plate 4 so as not to have an overlapping portion.

However, in the shrink-fitting method, there are variations in the panel side wall circumference during manufacturing, and the tightening force may sometimes be stronger than the standard. It is necessary to tighten with a stronger tightening force. For this reason, for example, when mild steel is used as the material for the metal strip 1 and the auxiliary plate 4, the same stress is applied to both, and in order to withstand this strong stress, folded portions 3 and 5 are formed at the transverse ends on the fluorescent surface side. need to be formed and strengthened. However, when resistance welding the auxiliary plate to the metal strip, including the folded part of the metal strip and the auxiliary plate, a gap 7 is created between the metal strip 1 and the auxiliary plate 4, so welding conditions must be controlled very strictly. Also, welding defects are likely to occur due to variations in welding conditions, and there is a risk of insufficient tightening stress and joint separation.

In order to reduce this gap 7, a method has been proposed in which the auxiliary plate 4 is bent in advance in steps 8 using a jig, as shown in FIG. 3, to reduce the gap between the metal band 1 and the auxiliary plate 4. Variations in the gap 7 due to manufacturing variations in the metal strip 1 and the auxiliary plate 4 cannot be completely eliminated.
Therefore, the effect of reducing the gap 7 is also extremely small.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide a reinforced cathode ray tube that is suitable for mass production and has an excellent reinforcing effect.

[Summary of the invention]

The present invention provides reinforcement in which the outer periphery of the side wall of a substantially rectangular panel having a fluorescent screen on the inner surface is tightened by a metal band which is given an elongation rate that exceeds the elastic limit and is joined in an annular shape through an auxiliary plate. In the type cathode ray tube, the short side end of the metal band on the side closer to the phosphor screen has a double structure by folding back, and both the long side ends of the metal band are placed on one surface of the auxiliary plate without overlapping each other. the auxiliary plate is joined in an annular shape in the positioned state, and both ends of the auxiliary plate in the width direction have double structure parts folded back in opposite directions, and one end of the auxiliary plate has the double structure part. By configuring the part to face the end of the double structure part of the metal strip, the tightening stress around the entire circumference of the panel side wall is made more uniform, and sufficient bonding strength is ensured by the auxiliary plates at both ends of the metal strip. It is something.

[Embodiments of the invention]

In the shrink-fitting reinforcement method, it is preferable to use a metal strip with an elongation rate exceeding its elastic limit so that the change in tightening stress is reduced in response to changes in the amount of elongation of the metal strip. For example, when using a mild steel plate for the metal strip, the elastic limit is exceeded when the elongation rate of the mild steel plate is approximately 0.13% or more, but considering manufacturing variations, the elongation rate is 0.3%.
It is recommended to use it in a range of 0.5% to 0.5%.

FIG. 4 shows an embodiment of the metal band applied to the present invention, and shows a cross section of the joint between the metal band 1 and the auxiliary plate 4. In FIG. 4, the metal strip 1 forms a double structure with a folded portion 3 in the lateral direction on the fluorescent surface side. The folded end of the folded portion 3 is folded back toward the side that does not come into contact with a panel (not shown), that is, toward the outside. On the other hand, the auxiliary plate 4 has a double structure having folded parts 5 and 6 on both sides in the transverse direction. These folded parts 5 and 6
are folded back so that the folded ends thereof are in opposite directions to both sides of the auxiliary plate 4. When joining the metal band 1 and the auxiliary plate 4, they are arranged so that the folded ends of their folded parts do not overlap. That is, as shown in FIG. 4, the folded ends of both folded parts 6 and 3 are aligned so that one of the folded parts 6 of the auxiliary plate 4 is located in the transverse direction of the side where the folded part 3 of the metal strip 1 does not exist. 6-1 and 3-1 are arranged so as to face each other in the transverse direction. With this configuration, no unbalanced gap is created between the metal strip 1 and the auxiliary plate 4.

Therefore, since the bond between the two can be made sufficiently strong,
The risk of joint separation and insufficient tightening stress can be significantly reduced, and welding can be easily performed.

To tighten such a metal strip to the cathode ray tube,
First, as shown in Figure 4, one end of the short side is approximately 12mm.
Both ends of the metal strip 1, which has been folded back to a width of approximately 45 mm to 50 mm, are brought together, and the auxiliary plate 4 is brought into contact with the mating portion as shown in Figure 4, and welded. Fix it more firmly. At this time, the inner circumference of the annular metal band 1 is configured to be slightly shorter than the outer circumference of the panel side wall of the cathode ray tube to which it is applied, and it is heated and stretched and fitted onto the panel side wall at an elongation rate that exceeds the elastic limit. Tighten. For example, when applying to a 20-inch cathode ray tube, the elongation rate of the metal band is
It may be set to about 0.4%.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a reinforced cathode ray tube tightened with a reinforcing band having more uniform tightening stress and sufficient bonding strength over the entire circumference of the panel side wall.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway schematic perspective view showing an annular reinforcing band consisting of a metal band and an auxiliary plate, Figs. 2 and 3 are schematic sectional views showing the joint between the metal band and the auxiliary plate, and Fig. 4
The figure is a schematic sectional view of a joint between a metal band and an auxiliary plate showing an embodiment of the present invention. 1...Metal band, 2...Joint part, 3, 5, 6...
Folded portion, 4... Auxiliary plate, 3-1, 6-1...
Folded end.

Claims (1)

[Claims] 1 A reinforced cathode ray that tightens the outer periphery of the side wall of a substantially rectangular panel with a phosphor screen on the inner surface by a metal band that is given an elongation rate that exceeds the elastic limit and is joined in an annular shape via an auxiliary plate. In the tube, the short side end of the metal band on the side closer to the phosphor screen has a double structure by folding back, and both ends of the metal band in the longitudinal direction are located on one surface of the auxiliary plate without overlapping each other. the auxiliary plate is joined in an annular shape, and both ends of the auxiliary plate in the transverse direction have double structure parts folded back in opposite directions, and one end of the auxiliary plate has the double structure part. 1. A reinforced cathode ray tube characterized in that the metal strip is configured to face an end of a double structure section.