JP2004146195A - Shadow mask stretching device and stretching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that in the case a shadow mask flat plate is stretched in a state that the masking frames are pressurized, the masking frames receive unreasonable force from adjusting pins in pressurizing the masking frames and have nonuniform strains to the masking frames, and that uniform tensile forces cannot be given to the shadow mask flat plate. <P>SOLUTION: When the masking frames 1a, 1b are pressurized by a pressurizing unit 6, by the action of vertical sliding mechanism part 5, adjusting pins 4 slide linked to displacement of the masking frames 1a, 1b. Therefore, when the masking frames are pressurized, the masking frames are incidentally displaced without giving unreasonable forces to the masking frames in the vertical direction, and the strains occurring in the masking frames after pressurization become uniform. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shadow mask stretching apparatus and a stretching method, and more particularly to an apparatus and a method for stretching a shadow mask used for a color cathode ray tube of a television receiver or the like on a mask frame.
[0002]
[Prior art]
A color cathode ray tube (CRT) is provided with a shadow mask for color selection. The shadow mask is stretched over a mask frame, and is fixed at a predetermined position in the color cathode ray tube via the mask frame.
[0003]
FIG. 6 shows a conventional method of stretching a shadow mask on a mask frame. 6, the shadow mask flat plate 3 is held in a state where tension is given by the lower chuck 7 and the upper chuck 8. The mask frame (only one frame 1b constituting the mask frame is shown in the figure) is held and fixed by the adjustment pins 4, and is welded in a state in which the mask frame is deformed inward by pressing by the pressing unit 6. Thereby, the shadow mask flat plate 3 to which tension is applied is bonded.
[0004]
[Patent Document 1]
JP 2000-149774 A
[Problems to be solved by the invention]
In the above-described conventional method, when the mask frame is pressed by the pressing unit 6, the frame 1b is held by the adjustment pins 4 so that the frame 1b does not fall downward (so that the mask frame 1b always rises upward). are doing. However, in such a method, the frame 1b receives an unreasonable force (N in the figure; a force larger than required to support the mask frame) from the adjustment pin 4 in the vertical direction at the time of pressurization. Non-uniform strain occurs in 1b. For example, as shown in FIG. 7, four (7) sets of the pressing units 6 hold the four corners of the mask frame with four adjusting pins 4 to add the frames 1a and 1b in the directions of the arrows in the figure. It was confirmed by observations by the inventors that when pressure was applied, as shown by the broken line in FIG. As a result, if the pressure on the mask frame is released after welding the shadow mask flat plate 3, uneven tension is generated in the shadow mask flat plate 3, which causes deterioration of the performance of the cathode ray tube. Further, for example, if there is a difference in the strain on the left and right sides of the mask frame (the left and right direction in FIG. 8), plastic deformation occurs on the shadow mask flat plate during welding, and wrinkles may occur on the shadow mask.
[0006]
Therefore, an object of the present invention is to provide a shadow mask stretching apparatus and a stretching method capable of pressing a mask frame without generating uneven strain on the mask frame when the shadow mask is stretched on the mask frame. To provide.
[0007]
[Means for Solving the Problems]
The present invention has the following features to attain the object mentioned above. The reference numerals in parentheses indicate the correspondence with the embodiment described later to facilitate understanding of the present invention, and do not limit the present invention in any way.
[0008]
The shadow mask stretching apparatus of the present invention includes an adjusting pin (4) for holding a mask frame (1a, 1b, 2a, 2b) and a pressing unit (6) for pressing a side surface of the mask frame inward of the mask frame. A vertical sliding mechanism (5) for allowing the adjustment pin to be slid in the vertical direction in conjunction with the displacement of the mask frame accompanying the pressurization by the pressurizing unit; and a mask frame pressurized by the pressurizing unit. And a joining means (9) for joining the mask and the shadow mask.
[0009]
The vertical sliding mechanism may be, for example, a spring mechanism, or may be a mechanism that moves the adjustment pin mechanically in conjunction with the displacement of the pressure unit, Other mechanisms may be used. Particularly preferred mechanisms include an air cylinder and a hydraulic cylinder.
[0010]
In addition, any known joining means can be used as the joining means. A typical example is a welding electrode for joining a mask frame and a shadow mask by welding.
[0011]
Further, in the shadow mask stretching method of the present invention, the mask frame (1a, 1b, 2a, 2b) is held slidably in the vertical direction, and the side surface of the held mask frame is pressed inward of the mask frame. And a step of joining the deformed mask frame and the shadow mask flat plate (3).
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a view schematically showing a process of stretching a shadow mask on a mask frame. FIG. 1A shows a state before welding, and FIG. 1B shows a state after welding. The mask frame is composed of, for example, four frames 1a, 1b, 2a, 2b, and a shadow mask flat plate 3 is stretched over the mask frame. However, the present invention is not limited to the mask frame, and the present invention can be applied to a case where the mask frame is formed of one member.
[0013]
When the shadow mask plate 3 is stretched over the mask frames 1a, 1b, 2a, 2b, the frames 1a, 1b are preliminarily pressed inward (in the direction of the arrow in FIG. 1A) to displace the mask frame. In this state, the frames 1a and 1b and the shadow mask flat plate 3 are welded. At this time, the shadow mask flat plate 3 is welded with tension applied in advance. Thereafter, when the pressure applied to the mask frame is released, the desired tension is maintained on the shadow mask flat plate 3 by the tension previously applied to the shadow mask flat plate 3 and the force of the mask frame returning to the original state from the deformed state. (The direction of the arrow in FIG. 1B).
[0014]
Hereinafter, the configuration of the shadow mask stretching apparatus of the present embodiment will be described. FIG. 2 is a view when a mask frame is set on the shadow mask stretching apparatus (a state before the mask frame is pressed) when viewed from the side, and FIG. 3 is a view after the mask frame is pressed. It is.
[0015]
First, a state before pressurizing the mask frame will be described. In FIG. 2, a mask frame (only the frames 1a and 1b are shown in the figure) is held at a predetermined height by adjusting pins 4, on which a shadow mask flat plate 3 is held by a lower chuck 7. A plurality of pressurizing units 6 are provided outside the frames 1a and 1b at opposing positions. In addition, the present apparatus is provided with a vertical sliding mechanism 5 that holds the adjust pin 4 slidably in the vertical direction as a characteristic configuration of the present invention. Before pressurization of the mask frame, the adjust pin 4 holds the mask frame with a force (N1 in the figure) corresponding to the weight of the mask frame.
[0016]
Next, the state after pressurizing the mask frame will be described. 3, the shadow mask flat plate 3 is gripped by an upper chuck 8 and a lower chuck 7, and is pulled in the direction of the arrow shown in the figure. On the other hand, the frames 1a and 1b are pressed by the pressing unit 6 in the direction of the arrow shown in the figure. When the frames 1a and 1b are pressed by the pressing unit 6, the long portions (L-shaped vertical portions) of the frames 1a and 1b are displaced inward of the mask frame. The short part (L-shaped horizontal part) tends to be displaced downward. In the present device, the adjust pin 4 is lowered in conjunction with the downward displacement of the short portion. As a result, the adjust pin 4 holds the mask frame with almost the same force (N2 in the drawing) even after pressurization of the mask frame as before. Therefore, after pressurizing the mask frame, the frames 1a and 1b do not receive excessive force from the adjust pin 4 in the vertical direction as in the related art. In this state, the shadow mask flat plate 3 and the frames 1a and 1b are joined by the welding electrode 9. Note that the “force substantially equal to that before pressurization” means that there may be a difference that does not cause uneven strain in the mask frame after pressurization.
[0017]
As the vertical sliding mechanism 5, any mechanism can be used as long as the adjusting pin 4 can hold the mask frame with almost the same force even after pressurizing the mask frame as before. For example, a spring mechanism may be used, or a mechanism that moves the adjustment pin 4 mechanically in conjunction with the displacement of the pressure unit 6 may be used. Particularly preferred mechanisms include an air cylinder and a hydraulic cylinder. By using these known cylinder mechanisms, vertical sliding can be performed more smoothly, and in the process of displacement of the mask frame, the adjust pin 4 always holds the mask frame with almost the same force as before the mask frame is pressed. Such an ideal vertical sliding mechanism can be easily realized without requiring a high-precision design.
[0018]
The contact point between the frames 1a, 1b and the adjustment pins 4 changes with the displacement of the frames 1a, 1b due to the pressurization of the mask frame. FIG. 4A shows a state before pressurizing the mask frame, and FIG. 4B shows a state after pressurizing. As can be seen from FIG. 4, the short portion (L-shaped horizontal portion) of the frame 1 b (the same applies to the frame 1 a) moves to the outside of the mask frame while displacing the tip of the adjustment pin 4 with the pressurization. If the frictional resistance at this time is large, the movement of the frame 1b is not performed smoothly, and as a result, unevenness may occur in the frame 1b. Therefore, in order to minimize the frictional resistance when the frame 1b is displaced, it is preferable that the tip of the adjusting pin 4 has an R shape. This makes it possible for the short portion of the frame 1b to move while smoothly sliding on the tip of the adjustment pin 4.
[0019]
As described above, in the present embodiment, when pressurizing the mask frame, the adjustment pin slides in conjunction with the displacement of the mask frame. Therefore, when the mask frame is pressed, the mask frame is freely displaced downward without applying an excessive force in the vertical direction to the mask frame, and the strain generated in the mask frame after the pressing is uniform as shown in FIG. (In FIG. 5, there is only one raised portion). As a result, a uniform tension can be applied to the shadow mask flat plate 3 without causing plastic deformation.
[0020]
Further, in the conventional shadow mask stretching apparatus, a holding force of 500 N to 1000 N is required for the adjusting pin 4, so that a firm holding structure is required. In the present embodiment, however, the degree of supporting the mask frame (or more than that) Since only a slightly larger holding force is required, a rigid holding structure is not required. Therefore, the adjusting pin 4 can be realized at lower cost.
[0021]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the occurrence of uneven strain on the mask frame when the mask frame is pressed, and as a result, to apply uniform tension to the shadow mask flat plate stretched over the mask frame. can do. Further, since a large force is not applied to the adjust pin as compared with the conventional case, a rigid holding structure is not required.
[Brief description of the drawings]
FIG. 1 is a view schematically showing a process of stretching a shadow mask on a mask frame.
FIG. 2 is a cross-sectional view showing a state before pressurizing the mask frame of the shadow mask stretching apparatus according to the embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a state after the mask frame is pressed by the shadow mask stretching apparatus according to the embodiment of the present invention.
FIG. 4 is a view showing a shape of an adjustment pin.
FIG. 5 is a side view showing how the mask frame is deformed when pressure is applied to the mask frame in the shadow mask stretching apparatus according to one embodiment of the present invention.
FIG. 6 is a cross-sectional view partially showing a state in which a conventional shadow mask stretching apparatus presses a mask frame.
FIG. 7 is a diagram illustrating an example of a positional relationship among a mask frame, an adjustment pin, and a pressure unit.
FIG. 8 is a side view showing how a mask frame is deformed when pressure is applied to the mask frame in a conventional shadow mask stretching apparatus.
[Explanation of symbols]
1a, 1b, 2a, 2b Frame 3 Shadow mask plate 4 Adjust pin 5 Vertical sliding mechanism 6 Pressing unit 7 Lower chuck 8 Upper chuck 9 Welding electrode

Claims (5)

Adjusting pins that hold the mask frame,
A pressure unit for pressing the side of the mask frame inward of the mask frame,
An up-down sliding mechanism that allows the adjust pin to be slid in the vertical direction in conjunction with the displacement of the mask frame accompanying the pressurization by the pressurizing unit,
A shadow mask stretching apparatus comprising: a joining means for joining the mask frame pressurized by the pressurizing unit to the shadow mask. 2. The shadow mask stretching apparatus according to claim 1, wherein the adjusting pin holds the mask frame with a force substantially equal to that before the pressing after the pressing of the mask frame by the pressing unit. 3. The shadow mask stretching apparatus according to claim 1, wherein the vertical sliding mechanism is an air cylinder or a hydraulic cylinder. 2. The shadow mask stretching apparatus according to claim 1, wherein a shape of a portion of the adjust pin that is in contact with the mask frame is an R shape. 3. A step of holding the mask frame slidably in the vertical direction,
A step of pressing the held side of the mask frame inward of the mask frame,
Joining the pressurized mask frame and the flat plate of the shadow mask.

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