JPH056788B2 - - 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 toward the inside of the envelope, and the substantially rectangular side wall portion of the panel toward the envelope. Strong pressure 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 services, the explosion-proof method that mechanically pulls and tightens one end of the metal strip does not provide a uniform tightening force due to the frictional force between the metal strip and the side wall of the panel. 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, with 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, and the curved surface of the panel part with large tubes and fluorescent surfaces is flat. Then, 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. It is necessary to form and strengthen the plate, or to increase the thickness of both plates. However, when resistance welding the bookkeeping plate to the metal band, including the folded part of the metal band and auxiliary plate, two double-layered parts, that is, four mild steel plates, are to be welded at the same time, so welding conditions must be controlled. Even if the conditions are extremely strict, welding defects are likely to occur due to variations in welding conditions, and there is a risk of insufficient tightening stress and separation of the joint. Furthermore, as the thickness of the metal band and the auxiliary plate increases, the above-mentioned welding defects are more likely to occur.

[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]

In the present invention, both ends of the metal strip are joined in an annular shape through an auxiliary plate so as not to have an overlapping part, and the stress per unit area at the elongation rate when the auxiliary plate is tightened is By configuring it so that the stress is greater than the stress per unit area at the elongation rate, the tightening stress around the entire circumference of the panel side wall is made more uniform, and sufficient matching strength is ensured by the auxiliary plates at both ends of the metal strip. .

[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 a mild steel plate is used for the metal strip, the elastic limit is exceeded when the elongation rate of the mild steel plate is about 0.13% or more, but it is preferable to use the elongation rate within a range of 0.3% to 0.5% in consideration of manufacturing variations.

That is, the cross-sectional area of the metal strip is S _B , the stress per unit area at the elongation rate during tightening in the region exceeding the elastic limit is σ _B , and the cross-sectional area of the auxiliary plate is S _A , When the stress per unit area at the elongation rate during tightening in the area _σ In order to obtain the stress, it is necessary that S _A σ _A ≒ S _B σ _B .

Further, in order for the metal band to withstand stronger stress and to ensure sufficient bonding strength by the auxiliary plate, the thickness of the auxiliary plate is preferably smaller than the substantial thickness of the metal band.
Therefore, the cross-sectional area of the auxiliary plate needs to be smaller than the cross-sectional area of the metal band, and from this reason as well, it is necessary that σ _A >σ _B. In other words, using the stress per unit area of a long metal strip as the minimum standard, σ _A > σ _B and S _A
By satisfying the condition σ _A ≒ S _B σ _B , it is possible to satisfy S _A < S _B , and it is possible to ensure a sufficiently uniform tightening stress and a sufficient matching strength.

Hereinafter, specific examples will be given and explained as examples of the present invention.

FIG. 3 is an enlarged view of a main part showing an embodiment of the present invention, and shows a cross section of the joint between the metal band 1 and the auxiliary plate 4. FIG. The fluorescent surface of the metal strip 1 has a folded portion 3 in the transverse direction, while the auxiliary plate 4 has a substantially flat plate shape formed in steps to match the outer surface shape of the folded portion 3 of the metal strip 1. be. A case will be described in which a reinforcing band consisting of the metal band 1 and the auxiliary plate 4 is applied to a 20-inch cathode ray tube and tightened at an elongation rate of 0.4%, which exceeds the elastic limit. Metal strip 1 is 0.8mm thick
It is made of mild steel plate, and has a total width of 47 mm in the short direction, with a folded part about 12 mm wide from the fluorescent surface side, and the actual width is 35 mm. On the other hand, the auxiliary plate 4 is made of a stainless steel plate with a thickness of 1 mm, and its width in the transverse direction is 35 mm.

The stress per unit area of the metal strip 1 made of a mild steel plate at an elongation rate of 0.4% is about 27 Kg/mm ² , and when multiplied by the cross-sectional area of 37.6 mm ² , a tightening stress of about 1015 Kg is obtained. The stress per unit area of the auxiliary plate 4 made of stainless steel plate at an elongation rate of 0.4% is approximately 31 kg/
mm ² , and when multiplied by the cross-sectional area of 35 mm ² , a tightening stress of approximately 1085 kg is obtained, which can be made substantially equal to the stress of the metal strip 1, and can provide a uniform tightening stress over the entire circumference of the panel side wall. did it. Furthermore, regarding the joint between the metal band 1 and the auxiliary plate 4, the metal band 1 is reinforced by a folded part 3, and the actual plate thickness of the reinforced part including this folded part 3 is 1.6
mm. On the other hand, the thickness of the auxiliary plate 4 is 1 mm, which is sufficiently thinner than the reinforcing portion of the metal plate 1, and since it has a three-layer structure as a whole, it is possible to ensure sufficient joint strength by resistance welding.

In the above embodiment, an example was explained in which a single plate with no folded parts was used as the auxiliary plate, but it would be better to use a material with a large stress per unit area. Therefore, the auxiliary plate may be provided with a folded portion if necessary, taking into consideration the bonding strength.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a reinforced cathode ray tube that is tightened with a reinforcing pair that has uniform tightening stress and sufficient joint 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, Fig. 2 is a schematic sectional view showing a metal band, an auxiliary plate, and a joint part, and Fig. 3 is an embodiment of the present invention. It is a schematic sectional view of the joint part of a metal band and an auxiliary plate showing an example. 1... Metal band, 2... Joint part, 3, 5... Turned part, 4... Reinforcement plate.

Claims (1)

[Scope of Claims] 1. A reinforced cathode ray tube in which the side wall portion of a substantially rectangular panel having a fluorescent surface on the inner surface is tightened with a metal band at an elongation rate exceeding the elastic limit of the metal band, Both ends of the metal band are joined in an annular shape through an auxiliary plate so as not to have an overlapping part, and the cross-sectional area of the auxiliary plate is smaller than the cross-sectional area of the metal band, and the elongation of the auxiliary plate when tightened is smaller than that of the metal band. 1. A reinforced cathode ray tube, wherein the stress per unit area at the rate of elongation is greater than the stress per unit area at the rate of elongation of the metal band when tightened. 2. Claim 1, wherein the lateral end of the metal band on the fluorescent surface side has a double structure by folding back, and the auxiliary plate has a flat plate shape.
Reinforced cathode ray tube as described in . 3. The reinforced cathode ray tube according to claim 1, wherein the metal band is made of mild steel and the auxiliary plate is made of stainless steel.