GB2237503A

GB2237503A - Cleaning apparatus for cleaning cathode ray tube panel

Info

Publication number: GB2237503A
Application number: GB8924085A
Authority: GB
Inventors: Samsung Electron Devices C Ltd; Dai-Jung Yun
Original assignee: Samsung Electron Devices Co Ltd
Current assignee: Samsung SDI Co Ltd
Priority date: 1989-10-26
Filing date: 1989-10-26
Publication date: 1991-05-08
Anticipated expiration: 2009-10-26
Also published as: GB2237503B; GB8924085D0

Abstract

Apparatus for cleaning a sealing portion of a panel of a cathode ray tube comprises a cleaning belt 40, guide roller assembly 10, cleaning fluid tank 50, and a mechanism 25, 25a for bringing an upper horizontal run of the belt into contact with a sealing portion of the panel in order to clean it and to remove it therefrom after cleaning. Guide rollers 14,15 are spaced from each other and so arranged that, in use, the sealing portion is cleaned by a horizontal run of the belt. The panel may be rotated during cleaning, less splashing of the phosphorescent layer on the panel is caused by use of the apparatus. <IMAGE>

Description

CLEANING DEVICE FOR SEALING PORTION OF THE PANEL OF COLOR PICTURE TUBE Field of the Invention The present invention relates to a cleaning device for the sealing portion of the panel of a color picture tube, and particularly to a cleaning device for the sealing portion of the panel of a color picture tube, in which a low rate of defective products, a high efficiency cf cleaning and a long life expectancy of the consumable parts are assured.

Background of the invention The cleaning device for the sealing portion of the panel of a color pit pre tube is indicative of a device which is capable of forcibly cleaning off the phosphorescent material and other dirts adhered to the sealing portion of the panel, and which is applied at an intermediate stage between the step of coating a phosphorescent slurry on the inner face of the panel and the step of optically exposing the phosphorescent layer made of the phosphorescent slurry.

The cleaning device of the sealed portion is for preventing the pollution of the optical exposing device when carrying out the optical exposure after the coating of the phosphorescent slurry.

A conventional cleaning device for the sealing portion of a color cathode ray tube is disclosed in Korean Utility Model Publication No. 83-511, the device disclosed in it being same or similar to that illustrated in Figure 1. That is, a pressing roller 4a and.a pair of guide rollers 1,1 for guiding a cleaning belt 5 of a loop type are provided in the interior of and above a cleaning fluid tank 9, while the pressing roller 4a is coupled with the leading end of a roller arm 4 which is pivotable by a certain angular distance by a pneumatic cylinder 7 and a compression spring 8. A driving roller 6 is installed at an intermediate height of the cleaning belt 5 for forcibly driving the cleaning belt 5.

In the conventional cleaning device as described above, the roller arm 4 is pivoted by means of the pneumatic cylinder 7 so as for the pressing roller 4a coupled with the leading end of the roller arm 4 to be press-contacted onto the sealing portion of the panel, and therefore, the movable cleaning belt 5 is capable of cleaning forcibly the sealing portion 3' of the panel through the frictional force of the cleaning belt 5. In this device, the pressing force between the sealing portion 3' and the cleaning belt 5 is generated by the force of the compression spring 8 which is installed between the roller arm 4 and the pneumatic cylinder 7, and therefore, there is the apprehension that the compressed displacement of the compression spring 8 can not be uniform depending on the positional variation of the panel.

That is, if the compressed dispacement of the compression spring 8 is varied, the cleaning pressure for the sealing portion of the incoming panel can become nonuniform, with the result that the cleaning pressure is greatly deviated from the preset reference pressure, thereby making it impossible to gain a sufficient cleaning ffect, or thereby leading to the prompting of the wearing of the cleaning belt 5 if a sufficient cleaning effect if obtained.

To mention about the greatest disadvantage of the above described cleaning device, the cleaning fluid can splash toward the inner area of the panel during the cleaning operation due to the cleaning frictions, and therefore, there is the problem that the phosphorescent layer can be damaged. As shown in Figure 1, the roller arm 4 coupled with the pressing roller 4a are installed almost vertically in such a manner as to be pivotable to the left and right, while the panel 3 approached to it is disposed in a slope of about 45 degrees. Thus, some area of the inner surface of the panel is located below the pressing roller 4a, making it easy for the splashing cleaning fluid to be intruded into the inner area of the panel.

Further, the above described conventional cleaning device is not provided with a means for removing the excess cleaning fluid from the cleaning belt, and therefore, there is a structural disadvantage by which the splashing cleaning fluid is inevitably led toward the inner area of the panel.

Summarv of the Invention Therefore, it is an-object of the present invention to provide a cleaning device for the sealing portion of the panel of a color picture tube, in which a uniform cleaning pressure is provided, and the rate of defective products due to the splashing of the cleaing fluid can be inhibited.

It is another object of the present invention to provide a cleaning device for the sealing of the panel of a color picture tube, in which the productivity is improved, and the wearing of the consumable parts can be lowered.

In achieving the above objects, the device of the present invention comprises: a cleaning fluid tank for storing the cleaning fluid; a cleaning belt moving between the interior of the cleaning fluid tank and a closed space formed above the tank; a group of rollers for guiding the cleaning belt; and a means for contacting and separating the cleaning belt to and from the sealing portion of the panel, wherein at least two of the upper rollers of the above mentioned rollers are disposed at a certain interval on a same horizontal level so as for the cleaning belt guided by the rollers to be moved along a substantially horizontal path when running the uppermost level, and at least one of the upper rollers is installed movably up and down so as for the cleaning belt guided by it to be contacted and detached to and from the sealing portion of the panel from below in the vertical direction.

Brief Descrintion of the Drawings The above objects and other advantages of the present invention will become more apparent by describing in detail the preferred embodiments of the present invention with reference to the attached drawing in which: Figure 1 is a partly cut out schematical side view of a conventional cleaning device for the sealing portion of the panel of a color cathode ray tube; Figure 2 is a partly cut out schematical side view of the cleaning device for the sealing portion of the panel of a color cathode ray tube according to the preferred embodiment of the present invention; Figure 3 is a frontal view of the cleaning device of Figure 2; and Figure 4 is a rear view of the cleaning device of Figure 2.

DescriDtion of the Dreferred embodiment As shown in Figure 2, a lateral beam 21 is extended from a first supporting pole 20 toward one side thereof, and at the leading end of the lateral beam 21, there is installed a roller assembly 10 for guiding a cleaning belt 40 which runs through the interior of a cleaning fluid tank 50 and a closed space above the cleaning fluid tank 50.

The roller assembly 10 consists of a plurality of rollers 11, 12, 13, 14, 15 and a pair of side plates 16 for supporting and securing the rollers from the opposite sides thereof. The two upper rollers 14, 15 are installed on an approximate horizontal level at a certain short interval, while the lower roller 13 has a large diameter and is installed in such a manner that its lower part is submerged into the cleaning fluid of the cleaning fluid tank 50. At an intermediate height between the above described two kinds of rollers, there are installed the driving roller 11 and the intermediate rollers 12 disposed at the opposite sides of the driving roller 11. Meanwhile, the contact-moving portion of the lower roller, i.e., the bearing 13a disposed near the cleaning fluid tank 50 as shown in Figures 3 and 4, but is arranged such that the cleaning fluid can not intrude into it. Meanwhile, the shaft ila of the driving roller 11 among the above-mentioned rollers passes through the side plates 16, and is retained by a bearing 21a which is provided at the leading end of the lateral beam 21.

Further, this shaft Ila retained by the bearing 21a is connected through bevel gears 11b to a driving motor 30.

The side plates 16 are respectively provided with extended portions 17 which opposingly face each other, while a connecting rod 18 is coupled with the leading ends of the extended portions 17. A wire 27 is guided by a wire pulley 24 which is installed at the top of a second supporting pole 23 which is in turn supported by a base 22, and one end of the wire 27 is secured to the connecting rod 18, while a weight 26 is suspended at the other end of the wire 27. The weight 26 which imposes a tension to the wire 27 consists of several separate units, so that the adjustment of the total weight should be possible.

A pneumatic or hydraulic cylinder 25 is pin-coupled to the base 22, and an actuation rod 25a projected from the top of the cylinder 25 is extended up to the connecting rods 8.

As shown in Figure 4, the connecting rod 18 and the actuation rod 25a are coupled slidably each other, while a stopper 25b is provided at the top of the actuation rod so as for the connecting rod 18 not to be departed from the actuation rod 25a.

The device according to the present invention constituted as above will now be described as to its operations.

As shown in Figure 2, if a panel 60 is disposed so as for the inner area of the panel 60 to face downwardly, if the panel 60 is slowly turned, and if the actuation rod 25a of the cylinder 25 is raised, then as shown in Figure 2 by the one-dot chain line, the roller assembly 10 is pivoted in the clockwise direction due to the gravity of the weight 26.

Then, if the driving motor is started, the driving roller 11 and the other rollers disposed in the vicinities are revolved at proper speeds, and accordingly, the cleaning belt 40 is circulated through the upper and lower closed spaces. Under this situation, the cleaning belt 40 is deprived of the excess cleaning water due to the action of pressing during its running through between the driving roller 11 and the intermediate rollers 12,12, and cleans the sealing portion 3' of the panel. After passing of the cleaning belt 40 around the upper rollers, the belt is again press-deprived of the excess fluid so as for the impurities to be removed from the belt.

After letting such process be run for a certain period of time, if the pneumatic cylinder 25 is activated, the roller assembly 10 is pivoted in the anticlockwise direction, so that the cleaning belt40 guided by the rollers is separated from the sealing portion of the panel.

As described above, the cleaning device for the sealing portion of the panel of a color cathode ray tube according to the present invention is capable of cleaning the sealing portion by means of a cleaning belt running horizontally and immediately below the panel, and therefore, the damage of the phosphorescent layer occurable due the splashing of the cleaning fluid can be inhibited to a great degree.

That is, the upper portion of the cleaning belt which contacts with the sealing portion of the panel holds a proper amount of the cleaning fluid, thereby reducing the apprehension that the cleaning fluid might splash. Further, even if a small amount of the cleaning fluid splashes, because the panel is located above the cleaning belt, there is little likelihood that the cleaning flui(? can jump up to the panel against the gravitational force.

Further, the cleaning pressure is maintained at a proper level owing to the gravity of the suspended weight so as for the splashing amount of the cleaning fluid to be extremely reduced. That is, the suspended weight according to the present invention assures that the cleaning belt should be contacted to the sealing portion of the panel with a constant pressure regardless of the setting position of the panel, thereby removing the variation of the contact pressure due to the variation of the compression amount of the spring, which was the disadvantage of the conventional technique disclosed in Korean Utility Model Publication No.

83-511.

Thus, according to the present invention, the cleaning pressure applied to the cleaning belt is maintained at a constant level, with the result that not only the cleaning is effectively carried out, but also the excessive wearing out of the cleaning belt can be prevented, thereby extending the life expectancy of the cleaning belt.

Among the above described rollers, the lower roller is installed in such a manner that its peripheral circumference should slightly touch the cleaning fluid contained in the tank, while the bearings installed at the both sides are disposed externally to the cleaning fluid reservoir, thereby preventing the ready corrosion of the contact-moving' portion unlike the conventional device in which the whole body of the roller is immersed within the cleaning fluid.

According to the experiment carried out by the present inventor, the life expectancy of the contact- moving portion, i.e., the bearing portion of the roller of the conventional device was two months, whereas the life expectancy of the bearing according to the present invention was about one year and 6 months.

The characteristics of the device of the present invention as described above can be summarized as follows; 1) The damage to the inner area of the phosphorescent layer due to the splashing of water drops is reduced to the minimum level.

2) The cleaning pressure applied to the portion to be cleaned is maintained regardless of the setting position of the panel, and the increase or decrease of the cleaning pressure is possible. Therefore, the life expectancy of the cleaning belt is greatly extended.

3) The life expectancy of the bearing portion of the lower roller is greatly extended.

The invention being thus described, it will be obvious that the same may be varied in many ways.

Such variations are not to be regarded as a departure from the scope of the invention.

There are described above novel features which the skilled man will appreciate give rise to advantages. These are each independent aspects of the invention to be covered by the present application, irrespective of whether or not they are included within the scope of the following claims.

Claims

CLAIMS:

1. A cleaning device for the sealing portion of the panel of a color cathode ray tube comprising; a cleaning fluid tank for storing a cleaning fluid; a cleaning belt running through the interior of said cleaning fluid tank and a closed space formed above said tank; rollers for guiding said cleaning belt; and a means for contacting and separating said cleaning belt to and from said sealing portion of the panel, characterized in that at least two upper rollers of said rollers are installed on an approximately same horizontal level at a certain interval between them so as for the cleaning belt guided by said rollers to~~run-approximately a horizontal path when running the uppermost portion of the running track.

2. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in claim 1, wherein at least one of said two upper rollers is installed movably up and down so as for said cleaning belt guided by said rollers to be contacted and separated to and from said sealing portion of the panel from below in the vertical direction.

3. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in claim 2, wherein all said rollers are installed between a pair of side plates (16) in such a manner that said rollers should be simultaneously operated through the action of said means for contacting and separating said cleaning belt.

4. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in any one of claims 2 and 3, wherein a press-contacting means for said cleaning belt is constituted such that a weight (26) is suspended by means of a wire '27) from a side of a roller assembly (10) which is supported pivotally by a first supporting pole (20), so as for the upper portion of said cleaning belt (40) passing around said rollers to be pushed by said weight (26) toward said sealing portion to be presscontacted to it to clean it, and a separating means is constituted such that it is capable of forcibly separating from said sealing portion of the panel said cleaning belt (40) which is presscontacted to said sealing portion of the panel by means of said weight (26) with a certain pressure.

5. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in claim 4, wherein said cleaning belt separating means includes a hydraulic or pneumatic cylinder (25) which is capable of pivoting said roller assembly (10).

6. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in claim 1, wherein at least a pair or more of said rollers are installed opposingly facingly each other with a certain gap therebetween, in such a manner that the excess cleaning fluid impregnated in said cleaning belt (40) passing through between said pair of rollers should be press-removed.

7. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in claim 6, wherein at least one or more of side rollers (12) are installed at one side or both sides of driving roller (11) closely with a certain gap therebetween, in such a manner that said cleaning belt passing along one side or both sides of said driving roller (11) should be press-squeezed.

8. The cleaning device for the sealing portion of the panel of a color cathode ray tube as claimed in any one of claims 2 and 3, wherein said lower roller (13) installed near the mouth of said cleaning fluid tank (50) is disposed such that a certain length of the circumference of said lower roller (13) should touch the cleaning fluid reservoir so as for the cleaning fluid not to intrude into the bearing lib.

9. Apparatus for cleaning the sealing edge portion of a panel for a cathode ray tube, the apparatus including an endless cleaning belt arranged to be driven around a plurality of guide rollers along a closed path a lower part of which passes through a reservoir of cleaning fluid, means being provided for pressing a portion of the moving belt against a said sealing edge portion, characterized by any one or more of the following features: a) said portion of said belt comprising a substantially horizontally running elongate uppermost portion thereof; b) said pressing means deriving the pressing force from a gravity system including a suspended weight; c) drive for the belt being provided by a drive roller, with a portion of the belt which is disposed above the reservoir squeezed between said drive roller and a said guide roller so as to remove excess cleaning fluid from the belt.

10. A cleaning device for the sealing portion of the panel of 9 color cathode ray tube, substantially as hereinbefore described with reference to figures 2 to 4 of the accompanying drawings.

11. A panel for a color cathode ray tube having a sealing edge cleaned by a cleaning device according to any preceding claim.

12. A color cathode ray tube including a panel according to claim 11.