JPH065607B2 - Device for measuring inner circumference of shrink fit band of explosion proof type cathode ray tube - Google Patents

Description

Description: [Object of the Invention] (Industrial field of application) The present invention relates to a device for measuring the inner circumference of a shrink-fitting band of an explosion-proof type cathode ray tube.

(Prior Art) Generally, as shown in FIG. 2, a cathode ray tube has a maximum diameter portion on the fluorescent screen (1) side for displaying an image, and a funnel-shaped cone portion (2) is joined or welded to this maximum diameter portion. The enclosure
(3) is provided. Since the inside of the envelope (3) is evacuated to a high vacuum, it may be imploded due to the external pressure applied to the envelope (3). In order to prevent this implosion, the above enclosure
It is known that the outer peripheral wall of the maximum diameter portion of (3) is provided with the explosion-proof means (4).

Conventionally, there are various types of explosion-proof means, but one of them is to form an annular metal band having an inner peripheral length slightly shorter than the peripheral length of the outer peripheral wall of the maximum diameter portion in advance. After heat-expanding, there is a method called a shrink-fitting method in which a cathode ray tube is inserted inside the tube and then cooled, and the annular band is attached to the outer peripheral wall of the maximum diameter portion.

Explosion proof by this shrink fit method uses the tightening force generated when the annular band having the inner peripheral length shorter than the peripheral length of the maximum diameter portion outer peripheral wall of the envelope is heated and expanded and then cooled in advance, It is extremely important to keep the relationship between the circumference of the outer peripheral wall of the maximum diameter part of the envelope and the inner circumference of the annular band constant, and if it is deviated, the tightening force of the band changes and the required explosion-proof effect is obtained. Will not be obtained. Therefore, in this shrink fit method, it is important to control the measurement of the inner circumference of the annular band.

FIG. 3 shows a conventional device for measuring the inner circumference of a shrink fit band. In this inner circumference length measuring device, four split jigs (7a), (7b), (7c), (7d) are attached to the base (6) by arrows (8a), (8b), (8c), It is arranged so as to be movable in the radial direction indicated by 8d). Each split jig
(7a), (7b), (7c), (7d) outer peripheral surface (9a), (9b), (9c), (9d),
A curved surface corresponding to the outer peripheral wall of the maximum diameter part of the cathode ray tube,
That is, it is formed on the inner curved surface of the annular band. Base
(6) and four split jigs (7a), (7b), (7c) and (7d) have an opening (10) formed in the center thereof, and the split jig is formed in this opening (10). A pressing die (11) having a wedge-shaped tip portion of the moving mechanism is arranged so as to be movable in the vertical direction indicated by an arrow (12).

The inner peripheral length of the shrink fitting annular band was measured by reducing the diameter to 4
Base so as to surround the individual split jigs (7a), (7b), (7c), (7d)
Place the annular band (13) on (6) and press the die (11) with the arrow (12).
In the direction of the arrow, and the pressing die (11) presses the four split jigs (7a), (7b), (7c), (7d) to the arrows (8a), (8b), (8c), By moving in the direction of (8d), the outer peripheral surface (9a), (9b), (9d) of the split jigs (7a), (7b), (7c), (7d) on the inner peripheral surface of the annular band (13). 9c), (9
This is done by pressing d). In this case, the inner peripheral length of the annular band (13) is, for example, the inner peripheral length of various annular bands having different peripheral lengths and the split jigs (7
A), (7b), (7c), (7d) outer peripheral surface (9a), (9b), (9c), (9d) to determine the relationship with the amount of movement of the die (11) when pressed By keeping the above, each split jig (7a), (7b), (7c), (7d) outer peripheral surface (9a), (9b), (9c), on the inner peripheral surface of the annular band (13), (9
The inner peripheral length of the band (13) can be measured from the moving amount of the pressing die (11) when pressing the d).

However, there are the following problems in measuring the inner circumference of the shrink fit band.

First, there are many types of bands for various types of cathode ray tubes that are produced, and correspondingly multiple types of split jigs (7
a), (7b), (7c) and (7d) are required. In addition, as the pipe becomes larger, the split jigs (7a), (7b), (7c), and (7d) also become larger, which increases the equipment cost for measuring the inner circumference and, at the same time, increases the size of the wide inner length measuring device. Installation space is required.

Secondly, since there are variations in the shape of shrink fitting bands of the same pipe type, the split jigs (7a), (7
b), (7c), (7d) outer peripheral surfaces (9a), (9b), (9c), (9d) are difficult to adhere to each other, and the split jig (7a) and band (13) are shown in FIG. The outer surface of the split jig and the band (1
A different gap (14) is formed between the inner peripheral surface of (3) and each band (13), and an error occurs due to the gap (14), resulting in low measurement accuracy.

(Problems to be Solved by the Invention) As described above, there are various types of explosion-proof means for a cathode ray tube from the related art, and one of them is an inner circumference slightly larger than the circumference of the outer peripheral wall of the maximum diameter part of the cathode ray tube envelope. A short-length annular metal band is formed, this annular band is heated and expanded, then a cathode ray tube is inserted inside it, and then it is cooled and the annular band is attached to the outer peripheral wall of the maximum diameter portion. Shrink fit There is a method called a method. In this shrink-fitting method, the relationship between the outer circumference of the outermost wall of the envelope and the inner circumference of the annular band is extremely important. Will not be obtained,
It is important to control the measurement of the inner circumference of the annular band.

However, the conventional device for measuring the inner circumference of the shrink fit band is
The structure is such that the outer peripheral surfaces of four split jigs that are movably arranged in the radial direction are pressed against the inner peripheral surface of the annular band by the die of the split jig moving mechanism. There are also many types of split jigs corresponding to this, and the split jigs are also becoming larger as the pipe becomes larger. There is a problem that the installation space for the length measuring device is required. In addition, since there is variation in the shape of the shrink fitting band of the same pipe type, it is difficult to make the outer peripheral surface of each split jig closely adhere to the inner peripheral surface of all annular bands. There is a different gap for each band between the inner surface of
There is a problem that an error occurs due to the gap and the measurement accuracy is low.

The present invention has been made to solve the above-mentioned problems, and at the same time reduces the equipment cost for measuring the inner circumference of the shrink-fitting band of the explosion-proof type cathode-ray tube, at the same time reduces the installation space, and measures accurately. The object is to construct a measuring device capable of performing.

[Means for Solving the Problems] (Means for Solving the Problems) In an inner peripheral length measuring device for a shrink-fitting band of an explosion-proof type cathode ray tube, the measuring device is provided with a plurality of split jigs or radiating members that are movable in a radial direction. Along the outer peripheral surface of the plurality of split jigs or elastic members, an inner frame made of an elastic member that can expand and contract in the direction, a drive device that radially drives the plurality of split jigs or elastic members. Arranged so that the elastic deformation easily occurs due to the radial movement of the plurality of split jigs or the radial expansion of the elastic member, which causes the inner frame to expand in diameter and to come into close contact with the inner circumference of the shrink fitting band of the cathode ray tube over substantially the entire length. It is composed of a strip-shaped spring member and a measuring device for measuring a distance between both ends of the spring member.

(Operation) As described above, along the outer circumference of a plurality of split jigs or elastic members, the radial movement of the split jigs or the expansion of the inner frame due to the radial expansion of the elastic members causes the cathode ray tube to expand. If a strip-shaped spring member that is in close contact with the inner circumference of the shrink-fitting band is arranged, elastic deformation of the strip-shaped spring member facilitates elastic deformation of the inner frame. The spring member can be brought into close contact with the shrink fitting band over substantially the entire inner circumference thereof. Therefore, the inner circumferential lengths of various bands can be accurately measured by measuring the distance between both ends of the strip-shaped spring member at that time.

(Embodiment) Hereinafter, the present invention will be described based on an embodiment with reference to the drawings.

FIG. 1 shows an apparatus for measuring the inner circumference of a shrink-fitting band of an explosion-proof type cathode ray tube, which is an embodiment thereof. In this inner circumference length measuring device, four split jigs (20a), (20b), (20c) and (20d) forming an inner frame of the device on the base (6) are indicated by arrows (8a), (8b), (8c), (8
It is arranged so that it can move in the radial direction shown in d). Outer peripheral surface (21a), (21b) of each split jig (20a), (20b), (20c), (20d),
Each of (21c) and (21d) is formed in a curved surface corresponding to the outer peripheral wall of the maximum diameter part of the cathode ray tube. Also, 4 split jigs
On the central side of (20a), (20b), (20c) and (20d), a circular opening (22) is formed by them. The split jigs (20a), (20b), (20c), and (20d) may be formed of synthetic resin such as light metal or vinyl chloride resin, but may be formed of a relatively flexible soft rubber or the like. It is more effective to form.

Around each of the four split jigs (20a), (20b), (20c), (20d), along their respective outer peripheral surfaces (21a), (21b), (21c), (21d),
A strip-shaped spring member (23), which is thin and elastically deformable, is arranged annularly. Terminal portions (24a), (24b) are attached to both ends of the spring member (23) in a direction orthogonal to the both ends,
At the position where the terminals (24a), (24) b are arranged, the space s between them is
A measuring device (25) such as a micro gauge for measuring is arranged.

In addition, inside the circular opening (22) constituted by the four split jigs (20a), (20b), (20c), (20d), each split jig (2
0a), (20b), (20c), (20d) is a spring (26) wound in a spiral shape for moving in the radial direction is arranged, the diameter can be arbitrarily expanded and reduced by a mechanism not shown. There is.

This device measures the inner circumference of the shrink fit band using the spring
The diameter of (26) is reduced to four split jigs (20a), (20b), (20c), (20d)
The inner frame constituted by is reduced in diameter, and the annular band (13) is arranged so as to surround the spring member (23) located outside the inner frame.
To place.

Then, by expanding the diameter of the spring (26), the four split jigs (2
0a), (20b), (20c), (20d) are moved in the radial directions indicated by arrows (8a), (8b), (8c), (8d) to expand the inner frame, and the spring member ( twenty three)
Is pressed against the inner peripheral surface of the annular band (13), and the distance s between the terminal portions (24a), (24b) attached to both ends of the spring member (23) at that time is measured.

That is, by using the spring member (23) having a known length, the distance s between the terminal portions (23) and (24b) is added to the length l of the member (23) to thereby form the annular band (13). ) Inner circumference is required.

By the way, like this measuring device, the four split jigs (20a), (2
0b), (20c), (20d) is arranged on the outside of the inner frame made of elastically deformable spring member (23), each split jig (20a), (2
0b), (20c), (20d) outer peripheral surface (21a), (21b), (21c), (21d) even if the shape of the annular band (13) does not match each split jig (2
0a), (20b), (20c), when moving (20d) in the radial direction to press the spring member (23) against the inner peripheral surface of the annular band (13),
Due to the elasticity of the spring member (23), the spring member (23) can be brought into close contact with the entire length of the inner peripheral surface of the annular band (13). Therefore, using the spring member (23) of known length, the interval s between the terminal portions (24a), (24b) when the spring member (23) is pressed against the inner peripheral surface of the annular band (13) is measured. As a result, the inner circumferential length of the annular band (13) can be accurately measured. The close contact of the spring member (22) with respect to the band (13) is achieved by composing each of the split jigs (20a), (20b), (20c) and (20d) with a relatively flexible material. As a result, the spring member (23) can be more closely attached to the inner peripheral surface of the annular band (13), and good results can be obtained.

Also, as described above, each split jig (20a), (20b), (20c), (20d)
The outer peripheral surface (21a), (21b), (21c), (21d) of the annular band (13)
Even if the shape does not match the shape of, the closeness can be obtained by the elasticity of the spring member (23) that one measuring device can accurately measure multiple types of bands (13) having different shapes and sizes. It is possible to significantly reduce the equipment cost of the measuring device and to reduce the installation space.

Although the inner frame is composed of four split jigs in the above embodiment, the split jig is not limited to four as long as the outer diameter of the inner frame can be increased or reduced.

Further, in the above embodiment, the inner frame is composed of the split jig, but this inner frame is a rubber balloon-like elastic member that can be expanded and contracted in the radial direction, and this elastic member is driven by pumping gas such as air. It may be configured such that it is expanded by the device and the gas thereof is discharged and contracted.

[Effects of the Invention] A plurality of split jigs that can move in the radial direction or elastic members that can expand and contract in the radial direction are used as the inner frame, and elastic deformation is easy along the outer circumference of the plurality of split jigs or elastic members. Even if the outer peripheral surface of each split jig or elastic member does not match the shape of the annular band, the radial movement of multiple split jigs or the radial expansion of elastic members When pressing the spring member against the inner peripheral surface of the annular band by
The strip-shaped spring member can be brought into close contact over substantially the entire length of the annular band, and by measuring the distance between both ends of the strip-shaped spring member at that time, the inner circumferential length of each annular band can be accurately measured. . Further, even if the outer peripheral surface of each split jig or elastic member does not match the shape of the annular band as described above, the strip-shaped spring member can be adhered over substantially the entire length of the annular band. Thus, it is possible to accurately measure the inner peripheral length of a plurality of types of annular bands having different shapes and sizes, reduce the equipment cost of the measuring device, and reduce the installation space.

[Brief description of drawings]

1 (a) and 1 (b) are a plan view and a BB cross-sectional view showing the configuration of an inner circumference length measuring device for a shrink-fitting band of an explosion-proof type cathode-ray tube according to an embodiment of the present invention, respectively, and FIG. Is a diagram of an explosion-proof cathode ray tube, and FIGS. 3 (a) and 3 (b) are a plan view and a BB cross-sectional view showing the structure of a conventional shrink-fitting band inner circumference measuring device for an explosion-proof cathode ray tube, respectively.
FIG. 4 is a diagram for explaining the problems of the conventional inner circumference length measuring device. 13 ... Annular band 20a to 20d ... Split jig 23 ... Strip-shaped spring member 25 ... Measuring device 26 ... Spring

Claims (1)

[Claims] 1. An inner frame composed of a plurality of radial jigs movable in the radial direction or elastic members capable of expanding and contracting in the radial direction, and a drive for driving the plurality of split jigs or elastic members in the radial direction. The device and the plurality of split jigs or elastic members are arranged along the outer peripheral surface, and the inner frame is expanded due to the radial movement of the plurality of split jigs or the radial expansion of the elastic members. Explosion-proof type, comprising: a strip-plate-shaped spring member that is elastically deformable and adheres to the shrink fitting band of a cathode-ray tube over substantially the entire length of the inner periphery of the band; and a measuring device that measures the distance between both ends of the spring member. Inner circumference measuring device for shrink fitting band of CRT.