JPH0121479Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to an explosion-proof cathode ray tube, and particularly to the structure of its explosion-proof metal strip.

Technical background of the invention and its problems The explosion-proof cathode ray tube has a structure as shown in Figure 1.

That is, on the outer periphery of the face plate side wall part 2 of the cathode ray tube, which consists of a face plate 1, a face plate side wall part 2, a funnel 3, and a neck 4, mounting holes _5-1 were bored at four corners of the face plate side wall part 2. An explosion-proof band made of an annular metal band to which a support fitting 5 is fixed by welding or the like is tightened by a shrink-fitting method via an adhesive tape 6 or the like.

There are two types of such explosion-proof bands: one is a ring-shaped metal band made by punching and forming the annular metal band 7 without joining, and the other is a ring-shaped metal band made by joining both ends of a long metal band by welding or the like. Both of these are formed to be slightly smaller than the outer periphery of the face plate side wall 2, and after being thermally expanded by heating, a cathode ray tube is inserted and the outer periphery of the face plate side wall 2 of the cathode ray tube is tightened to a predetermined tension. It is designed to provide an explosion-proof effect. In addition to this method, an explosion-proof method is also used in which a long metal strip is wrapped around the side wall and mechanically tightened, and the overlapping portions at both ends are welded and fixed.

Next, the state of close contact between the side wall portion 2 of the face plate and the metal band 7 will be explained.The cross section of the side wall portion 2 of the face plate is in a state as shown in FIG.

That is, in the side wall portion 2 of the face plate, a mold match line 2 _-1 , which is the most outwardly protruding portion, exists around the entire circumference of the side wall due to molding requirements. This mold mating line _2-1 is the outer 2nd line when molding the face plate 1.
This is the seam when two molds are put together. These molds require a punching taper in order to be pulled out in opposite directions up and down after the face plate 1 is formed, and generally have a taper of 1.5 degrees to 2.0 degrees. The amount corresponding to this taper,
The mold mating line _2-1 protrudes outward by an amount equal to the amount of misalignment when the upper mold and lower mold are combined.

Therefore, when the same part is tightened with a flat annular metal band 7, the thickness of the adhesive tape 6 is the smallest at the mold match line 2 _-1 , increases as it gets farther away, and then reaches the initial thickness, and beyond that, the thickness becomes the smallest at the mold match line 2 -1. A gap is created between the adhesive tape 6 and the annular metal band 7.

That is, this shows that the tightening force of the annular metal band 7 is concentrated on the mold match line 2 _-1 portion.

When a local tightening force is applied in this way, stress is concentrated in the same area and it is easily damaged, making it easy to break due to external impact. In the event of destruction, the effective adhesive width is small due to the poor adhesion between the face plate side wall 2, the adhesive tape 6, and the annular metal band 7, and the force to prevent the progress of destruction is small, resulting in insufficient explosion-proof performance.

Next, the relationship between the cross-sectional shape of the annular metal band shown in FIGS. 3 to 6 and the explosion-proof performance will be explained.

That is, FIG. 3 shows an almost straight plate-shaped ring metal band 7, and FIG. 4 shows an annular metal band 7 with its tip end bent at the opposite side from the face plate _7-1 , and both have a part that corresponds to the mold match line _2-1 . Since it is flat, it has the drawback that a strong tightening force is applied to the mold match line 2 _-1 as described above. Fig. 5 shows an annular metal band 7 whose upper part is bent toward the face plate from the bent part _7-2 that contacts the mold match line, which reduces the concentration of tightening force on the mold match line, but in practical use. Since the dimensions of the face plate and explosion-proof band are not constant, and there are also variations in the mounting position during the manufacture of cathode ray tubes, it is difficult to perfectly match the mold match line _2-1 and the bent part _7-2 , and it is difficult to ensure sufficient explosion-proofness. No effect will be obtained.

In FIG. 6, a bead is provided in which a portion of the annular metal band 7 corresponding to the mold match line 2 _-1 is bulged in the direction opposite to the panel 1.

In this structure, stress concentration on the mold match line _2-1 can be alleviated by increasing the length of the bead portion _7-3 in the vertical direction. However, with this structure, the tightening force is large near the bead portion _7-3 , but the tightening force decreases as it moves away from the bead portion 7-3, so there is a drawback that no complete tightening force can be obtained.

Also, although not shown, it is possible to combine the bent portion _7-2 of FIG. 5 and the bead portion _7-3 of FIG. 6, but the mold match line _2-1 and the bent portion _7-2 are completely aligned. If this is not done, it will not be possible to obtain a sufficiently uniform tightening force.

Purpose of the invention The present invention was devised in view of the conventional problems mentioned above, and its purpose is to provide a cathode ray tube with excellent explosion-proof performance.

Summary of the invention This invention is an explosion-proof cathode ray tube in which an explosion-proof band consisting of a metal band along the outer periphery of the side wall of the face plate of the cathode ray tube is tightened.
That is, the portion of the face plate corresponding to the mold match line is made into a groove to prevent the tightening force from being concentrated on the mold match line when tightened to the face plate, and to have a uniform tightening force throughout the explosion-proof band. This provides superior explosion-proof performance.

Embodiment of the invention The embodiments of the invention are shown below in Figures 7 to 2.
This will be explained using Figure 3.

First, a supporting metal member and a metal band are prepared. Among these, the support metal member is made of, for example, stainless steel or mild steel, and is formed into a substantially L-shaped support metal fitting 15 having a hole 15 _-1 as shown in FIG. If mild steel is used, it is advisable to further apply anti-corrosion treatment by galvanizing or chromate treatment. The metal band 17 is made of, for example, stainless steel, mild steel, or galvanized mild steel, and is provided with a thin wall portion _17-4 as shown in FIG. 8. This thin interior _17-4 is designed as a portion corresponding to the mold match line of the side wall of the face plate when explosion protection is implemented, and is processed by rolling, grinding, press molding, etc. Further, this processing may be performed after cutting a long metal strip into a predetermined size. Next, after cutting the annular metal strip to the length necessary to form it, both ends are joined at the overlapping part 18 at the welding point 18a as shown in FIG. 8, or by using another connecting metal (not shown). The plates are overlapped and connected by welding to form an annular metal band 17.

Furthermore, the support fitting 15 and the annular metal band 17 are welded and fixed at a welding point 15a. In this way, the explosion-proof band is completed.

Next, as shown in FIG.
Immediately after heating the tube to about 500° C. by high-frequency heating or gas burner heating, a cathode ray tube whose side wall is wrapped with adhesive tape 16 is inserted, and the cathode ray tube is fitted onto the side wall of the face plate of the cathode ray tube, thereby completing an explosion-proof cathode ray tube. That is, the metal band that has been expanded by heating contracts as it cools, tightening the side wall of the panel.

In addition, the embodiment of the cross-sectional shape of the annular metal band 17 of the explosion-proof band used in the above-mentioned explosion-proof cathode ray tube is shown in the 10th embodiment.
This is shown in FIGS. 1 to 16. In all of these, a thin wall portion _17-4 is formed on the annular metal band 17 at the portion corresponding to the mold match line on the side wall of the face plate, and the one shown in Fig. 10 is one in the form of a single straight plate. Yes, and Figures 11 and 12 show a folded part 1 in which both the upper and lower ends are folded back toward the face plate side.
7 _-5 and 17 _-6 are provided, and Fig. 12 shows this with the upper part bent toward the face plate side from the part corresponding to the mold match line.
Figures 13 and 14 show folded parts 17 _-1 and 17 whose upper and lower ends are folded back to the opposite side of the face plate.
_-7 , and FIG. 14 shows this with the upper part bent toward the face plate from the part corresponding to the mold match line, and FIGS. 15 and 16 show the end of the annular metal band 17. angle 17 _-8 ,
_17-9 has the corners removed to prevent scratching the side wall of the face plate and preventing the adhesive tape wrapped around the cathode ray tube from getting caught when the tube is inserted. Although not shown, the present invention can also be applied to a ring-shaped metal band with one end folded back.

The shape of the thin wall portion _17-4 is shown in FIGS. 17 to 20.
The shape shown in the figure as an example may be used, and the shape may be selected depending on the type of pipe to be applied, and the shape may be formed by rolling, grinding, pressing, or the like.

As shown in FIGS. 21 to 23, in an explosion-proof cathode ray tube that is tightened with such a metal band, the thin wall part _17-4 of the annular metal band 17 can be easily bent with a small force, so it can be bent easily with a small force. The mold match line and the annular metal band 1 bend easily due to the contraction force and bend from the part corresponding to the mold match line.
The annular metal band 17 is in close contact with the inclined side wall of the panel because the permissible width for positional deviation with respect to the metal band 7 is large. Further, the entire surface of the annular metal band 17 of the explosion-proof band can be tightened with uniform force without tightening strongly locally on the mold match line.

Effects of the invention As mentioned above, the explosion-proof cathode ray tube of the present invention does not tighten the mold match line strongly locally with the metal band, but tightens the entire face plate uniformly with the entire metal band, making it difficult to break due to impact etc. Even if the tube is destroyed by impact with a steel ball, etc., the effective area of the adhesive tape that adheres the explosion-proof band and the side wall of the face plate is long, so the progress of cracking is well prevented, so the risk of implosion of the cathode ray tube is extremely reduced. It has explosion-proof performance.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of an explosion-proof cathode ray tube, Fig. 2 is an enlarged cross-sectional view of main parts showing how the face plate and metal band of a conventional explosion-proof cathode ray tube are attached, and Figs. 3 to 6 are metal bands. 7 is a perspective view showing the support fittings, FIG. 8 is a side view showing the metal band, FIG. 9 is a front view showing the explosion-proof cathode ray tube, and FIGS. 10 to 16. The figure is a cross-sectional view showing the shape of a metal strip applied to the explosion-proof cathode ray tube of the present invention, FIGS. 17 to 20 are enlarged cross-sectional views of essential parts showing examples of the shape of the thin-walled part of the metal strip, and FIG. 21 23 are enlarged cross-sectional views of essential parts showing how the metal band is attached. 1... Face plate, 2 _-1 ... Mold match line, 16... Adhesive tape, 17... Metal band, 17 _-4 ... Thin wall portion.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In an explosion-proof cathode ray tube in which a side wall of a face plate having a mold match line is tightened with a metal band, a thin wall portion is provided on the entire circumference of the metal band corresponding to the mold match line. An explosion-proof cathode ray tube characterized by having. (2) The explosion-proof cathode ray tube according to claim 1, wherein the thin wall portion of the metal band is formed on both sides of the metal band corresponding to the mold match line.