JPH0415571B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for manufacturing an explosion-proof cathode ray tube,
In particular, the present invention relates to a method of manufacturing an explosion-proof cathode ray tube, which allows a tension band to be tightened almost uniformly on the side wall of a face plate of a rectangular cathode ray tube. [Technical Background of the Invention] For example, a T-band type explosion-proof cathode ray tube is normally manufactured by the following process. That is, as shown in FIG. 1, an adhesive tape 3 is wound around the side wall 2 of a rectangular face plate 1 having sides and corners, and a mounting bracket 4 is placed at the corner using a jig or the like. Next, one end ₅₁ of the tension band 5, which has been heated to a predetermined temperature using an electrical heating device (not shown), is fixed by a fixing jig 6 at the center of one side, and pulled in the direction of the arrow 7. while wrapping it around the adhesive tape 3 and the mounting bracket 4, cutting it under strong tension to a length that overlaps with the vicinity of one end ₅₁ , and fixing it by welding, and shrinking the tension band 5 when it cools. The side wall portion 2 is stretched to tighten it with even stronger tension to complete the explosion-proof cathode ray tube. [Problems with Background Art] However, according to the above-described method for manufacturing an explosion-proof cathode ray tube, when wrapping the tension band 5, the tightening force differs from side to side due to large frictional resistance at the corners. In other words, the tightening force of side 2 ₁ is
T ₁ , the tightening force of side 2 ₂ is T ₂ , the tightening force of side 2 ₃ is
T ₃ and the tightening force of the side 2 ₄ to which the tension band _{1 is welded are T 4 ,} and the final The magnitude of the tightening force applied to the surface generally has the following relationship: T ₃ > T ₂ > T ₁ ≒T ₄ . This general tightening force relationship is not necessarily constant, and may include variations in the surface condition of the mounting bracket, tension band, and valve dimensions, variations in the temperature of the band heated initially, and variations in the tightening machine. Differences occur between individual cathode ray tubes.
In order to make the tightening force constant on each side, it is extremely difficult to obtain sufficient uniformity even if you adjust the winding force of the machine, the amount of heating before winding, and the temperature distribution. . Further, it is practically impossible to adjust the clamping force to correspond to the difference in the tightening force of each side that changes individually. When the tightening force becomes uneven in this way, there is a problem in that the explosion-proofing effect decreases. [Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and provides a method for manufacturing an explosion-proof cathode ray tube that can apply a substantially uniform tightening force to the entire side wall of a face plate. The purpose is to [Summary of the Invention] That is, the present invention involves a process of winding an adhesive tape around the side wall of a rectangular face plate having sides and corners and arranging mounting hardware at the corners, or arranging an adhesive resin and a rim band. process, and a process of stretching and fixing a tension band over these,
This method of manufacturing an explosion-proof cathode ray tube comprises at least the step of heating a tensioned tension band to a predetermined temperature to expand it, and then cooling and tensioning it to equalize the tightening force. [Embodiment of the Invention] Next, a first embodiment of the method for manufacturing an explosion-proof cathode ray tube of the present invention will be described with reference to FIGS. 2 and 3. That is, as shown in FIG. 2, an adhesive tape 13 is wound around the side wall 12 of a rectangular face plate 11 having sides and corners, and a mounting bracket 14 is placed at the corner using a jig or the like. Then, the vicinity of one end 15 ₁ of the tension band 15 heated to a predetermined temperature by an electrical heating device (not shown) or the like is fixed by a fixing jig 16 provided near the center of one side 12 ₄ . Then, it is wrapped around the adhesive tape 13 and the mounting bracket 14 while being pulled in the direction of the arrow 17, and while being strongly taut, it is cut to a length that overlaps with the vicinity of one end ₁₅₁ and fixed by welding. After that, the process until the tension band 15 is stretched so as to tighten the side wall part with a predetermined tension due to contraction during cooling is almost the same as the conventional manufacturing method. The present invention is characterized in that it includes a step of heating the band 15 again. That is, the rectangular face plate 11 is supported by a vacuum chuck (not shown), and positioned by, for example, bringing one side 12 ₂ of the side wall portion 12 into contact with the jig 18 . Next, electrodes 19 ₁ and 19 2 made of braided copper wire or the like are electrically connected to the tension band 15 on the two opposing sides _{12 1} and _{12 3 ,}
By passing a current between the electrodes 19 ₁ and 19 ₂ , the entire circumference of the tension band 15 is reheated and then cooled. Since this reheating preferentially heats the tension band 15, it is ideal to perform it with a large current and in a short time. However, as the current increases, the heating time must be strictly controlled. On the other hand, if heating is performed for a long time with a small current, the heating time can be easily managed, but the rectangular face plate 11 will also be heated, and there is a risk of damaging the cathode ray tube. For example, in a 14-inch cathode ray tube, the current is 14
A. A heating time of 3 to 10 seconds is suitable. If it is less than 3 seconds, the amount of heating will be insufficient, and if it is more than 12 seconds, there is a risk that the tension band 15 may change color and spoil its appearance. By reheating the tension band as in this embodiment, the tension band 15 formed into an annular shape in the process shown in Fig. 3 thermally expands, reducing friction at the corners and completely releasing the tension. Alternatively, the tightening force is reduced, and among the sides of the tension band 15, the tightening force (tension band tension) is moved from the side where the tightening force (tension band tension) is weak to the side where the tightening force is strong through the corner. Since the tension band 15 is cooled from this state, the tightening force on each side becomes approximately uniform. Therefore, according to this method, the tightening force on each side 12 ₁ , 12 ₂ , 12 ₃ , 12 ₄ of the side wall portion 12 of the rectangular face plate 11, which has been a problem with conventional manufacturing methods, can be made almost uniform. This makes it possible to obtain an explosion-proof cathode ray tube with extremely good explosion-proof effect. The above embodiment has described a method for manufacturing a T-band type explosion-proof cathode ray tube, but this method for manufacturing an explosion-proof cathode ray tube involves arranging an adhesive resin and a rim band on the side wall of a face plate and stretching a tension band. It can also be applied to other types of explosion-proof cathode ray tubes, such as explosion-proof cathode ray tubes. In addition to current heating, high frequency heating and other heating methods can be used to reheat the tension band. In addition to welding, the connection and fixation after winding the tension band may be performed by a known method such as caulking. Next, a second embodiment of the present invention will be described. The method of applying explosion protection by wrapping a tension band that does not heat up has a larger side difference in tightening force than one that is heated, so the explosion protection effect is significantly insufficient, so it has traditionally been applied only to special types of cathode ray tubes. was. However, in this case as well, adhesive tape is wrapped around the side wall of the rectangular face plate, and mounting brackets are placed at the corners, or adhesive resin and rim bands are placed, and a tension band that is not heated is placed on top of the tension band that is heated. Even if the tension band is wrapped with a stronger tension than in the case of a tension band and fixed by welding, then heated in the same manner as in the first embodiment, and then cooled, the tightening force on each side is approximately reduced. It has become possible to make it uniform, and it has become possible to solve the problems of conventional explosion-proof methods of this type. As an example, for a 14-inch cathode ray tube, wrap an unheated tension band around it with a tightening force that is approximately 50% stronger so that the final tightening force is the same as that of a heated tension band. Both ends of the band were fixed by welding, and resistance heating was performed using the method of the first embodiment at a current of 14 A for 7 seconds (A), and this resistance heating was not performed (B). The table below shows the results of a forced destruction test of 20 pieces of each product and a pass/fail judgment based on internal standards.

〔Effect of the invention〕

As described above, according to the method for manufacturing an explosion-proof cathode ray tube of the present invention, it is possible to stretch a tension band having a substantially uniform tightening force over the entire side wall of a rectangular face plate, resulting in an extremely explosion-proof effect. Since a good explosion-proof cathode ray tube can be obtained, its industrial value is extremely large.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a conventional method for manufacturing an explosion-proof cathode ray tube, and FIGS. 2 and 3 are diagrams showing an example of a method for manufacturing an explosion-proof cathode ray tube according to the present invention. FIG. 3 is an explanatory diagram of the process of stretching the tension band, and FIG. 3 is an explanatory diagram of the process of reheating. 1, 11... Rectangular face plate, 2, 1
2... Side wall portion, 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ , 12 ₁ , 12
₂ , 12 ₃ , 12 ₄ ... Side part, 3, 13 ... Adhesive tape, 4, 14 ... Supporting metal fittings, 5, 15 ... Tension band, 6, 16 ... Fixing device, 19 ₁ ,
19 ₂ ...electrode.

Claims (1)

[Claims] 1. A tension band is wound around the side wall of a rectangular face plate having sides and corners, and both ends are connected and fixed by tension, and then the entire circumference of this tension band is heated. A method for manufacturing an explosion-proof cathode ray tube, which is characterized by expanding the tube, temporarily releasing or reducing the tension, and then tightening it again by cooling to equalize the tightening force. 2. A step of winding an adhesive tape around the side wall of a rectangular face plate having sides and corners and arranging a mounting bracket at the corner, and placing a template heated to a predetermined temperature on the adhesive tape and the mounting bracket. a step of stretching and fixing the tension band, and a step of reheating the entire circumference of the tension band, which has been stretched and fixed, to expand it and then cooling it to tension it again to equalize the tightening force. A method for manufacturing an explosion-proof cathode ray tube, comprising: 3. A step of arranging an adhesive resin and a rim band on the side wall of a rectangular face plate having sides and corners, a step of stretching and fixing a tension band heated to a predetermined temperature on the rim band, and fixing the tension band on the rim band. A method for manufacturing an explosion-proof cathode ray tube, comprising the steps of reheating the entire circumference of a tension band that is suspended and fixed, to expand it, and then tightening it again by cooling to equalize the tightening force. . 4. Winding an adhesive tape around the side wall of a rectangular face plate having sides and corners, and arranging a mounting bracket at the corner, and placing a tension band that does not heat on the adhesive tape and the mounting bracket. The tension band is stretched and fixed, and the entire circumference of the tension band that has been stretched and fixed is heated and expanded to temporarily release or reduce the tension, and then the tension is tightened by cooling and the tightening force is applied. A method for manufacturing an explosion-proof cathode ray tube characterized by uniformity. 5. A step of arranging an adhesive resin and a rim band on the side wall of a rectangular face plate having sides and corners, a step of stretching and fixing a tension band that does not heat over the rim band, and a step of fixing the tension band on the rim band; A method for manufacturing an explosion-proof cathode ray tube characterized by heating the entire circumference of a fixed tension band to expand it, temporarily releasing or reducing the tension, and then tightening it by cooling to equalize the tightening force. .