GB2243019A - Sealing apparatus for electron gun of cathode ray tube - Google Patents

Abstract

A sealing apparatus for welding an electron gun mount assembly to cathode ray tubes of different sizes includes frames (13) on a rotating index table (11). Support rods (12) support the electron gun mount assemblies (2); and heating means with nozzles (15, 15, 16 and 16) eject a flame to weld the neck portions (19) of the cathode ray tubes (1). The flames are adjusted according to the size of the cathode ray tube (1) which is detected by a detecting means near the index table (11). Fuel and oxygen supply lines having main lines and auxiliary lines are connected to the nozzles (15, 15, 16 and 16) and the flow of fuel and oxygen is controlled by a control means in response to the detecting means. In the figure 4 embodiment (not shown) there are 4 pairs of nozzles and each opposed pair of nozzles ejects a flame for a particular sized cathode ray tube when that sized tube is detected while the other opposed pair ejects a pilot flame. Thus this apparatus permits the sealing work to be performed according to the size of the cathode ray tubes, and the fuel consumption and the inferiority rate to be lowered. <IMAGE>

Description

SEALING APPARATUS FOR ELECTRON GUN OF CATHODE RAY TUBE The present invention relates to a sealing apparatus for fixedly welding an electron gun mount assembly to the neck of a cathode ray tube.

In general, a sealing apparatus for sealing an electron gun into the neck of a cathode ray tube is constructed as follows. A frame for mounting the cathode ray tube is rotatably installed onto the upper marginal edge of an index table. Thus, the cathode ray tube mounted on the frame is rotated while the index table turns around. A plurality of heating means are installed around and spaced apart a predetermined distance from the index table to correspond to the index angles of the index table, for welding both neck of the cathode ray tube mounted on the frame and the stem of the electron gun mount assembly fixedly inserted into the neck. The heating means for welding applies a flame of prescribed calorific values to the stem in increments.

Since such a sealing apparatus provides heat for fixedly welding the stem of the electron gun mount assembly and the neck of the cathode ray tube made of glass, the amounts of the heat applied to the cathode ray tube at the respective steps vary according to the respective indexed positions of the cathode ray tube conveyed by the index table in order to protect from cracking the portions of the cathode ray tube undergoing rapid heating and cooling. As described above, the states of the flame applied to the neck of the cathode ray tube depending on the indexed positions of the cathode ray tube, is one of the important factors in determining the quality of the cathode ray tube.

The construction of the conventional sealing apparatus will be described below in detail. As illustrated in Figure 1 of the accompanying drawings, the frame 13 for mounting the cathode ray tube is rotatably installed onto the marginal edge of the index table 11 turning by the prescribed angle. Referring to Figure 2A, the heating means is placed near the cathode ray tube for welding the neck la of the cathode ray tube 1 rotating with the frame 13, and two pairs of nozzles 16 incorporated in the heating means are installed on either side of the neck la of the cathode ray tube 1 for ejecting flame to supply heat. The nozzles 16 are commonly connected to fuel supply tubes 16c and oxygen supply tubes 16d as illustrated in Figure 2B.Accordingly, the nozzle 16 is designed to eject flame at a fixed pressure foi welding, so that only one size of the electron gun of the cathode ray tubes can be sealed by the nozzles 16. Thus, this is not suitable for compatibly carrying out the sealing work for various sizes of the cathode ray tubes. In addition, the nozzle 16 always ejects flame at a fixed pressure regardless of the mounting of the cathode ray tube on a frame 13, thereby wasting fuel.

The present invention is intended to overcome the above described disadvantages of the conventional technique.

Accordingly, it is the object of the present invention to provide a sealing apparatus for an electron gun of a cathode ray tube for making it possible to carry out sealing work for various sizes of the cathode ray tube, economize on fuel consumption, and reduce the deterioration of the cathode ray tubes during sealing.

According to the invention, there is provided a sealing apparatus for an electron gun of a cathode ray tube including an index table periodically turning by prescribed angles; a plurality of frames installed onto the marginal edge of the index table for mounting cathode ray tubes; a plurality of support rods positioned below the frames for supporting the electron gun mount assemblies inserted into the cathode ray tubes; and a plurality of heating means having a plurality of nozzles for ejecting flame to weld the neck portions of the cathode ray tubes, the nozzles being differentiated for ejecting flame to heat the neck of two or more than two sizes of the cathode ray tubes by adjusting calorific value of the flame, and further comprising: a plurality of complex fuel supply lines respectively connected to the nozzles of the heating means, having main lines discharging fuel and oxygen and auxiliary lines discharging fuel and oxygen less than that of the main lines; a plurality of valve means respectively installed at main lines and auxiliary lines for closing and opening the fuel and oxygen supply lines and controlling the flow of fuel and oxygen; a detecting means arranged near the turning route of the index table for detecting the sizes of the cathode ray tubes mounted on the frame; and a control means for controlling the closing and opening valve means installed at the supply lines to adjust the amount of the flame ejected from the nozzles in response to the signals detected by the detecting means.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which; Figure 1 is a partial perspective view of a conventional sealing apparatus for an electron gun of a cathode ray tube; Figure 2A is a side view showing the relative positions of the nozzles of the sealing apparatus illustrated in Figure 1 to an electron gun inserted in the neck of a cathode ray tube; Figure 2B is a horizontal sectional view showing the relative positions of the nozzles of the sealing apparatus illustrated in Figure 1 to an electron gun inserted in the neck of a cathode ray tube; Figure 3 is a partial perspective view of a sealing apparatus for an electron gun of a cathode ray tube according to an embodiment of the present invention; and Figure 4 illustrates fuel supply line connections to the nozzles of the sealing apparatus illustrated in Figure 3.

A preferred embodiment of the present invention will now be described in detail with reference to Figures 3 and 4 of the accompanying drawings.

A plurality of frames 13 for mounting cathode ray tubes are rotatably installed in a regular spaced-apart arrangement on the marginal edge of an index table 11. In Figure 3 only one frame is illustrated so that a detailed view can be shown. A support rod 12 for supporting an electron gun mount assembly 2 inserted in the neck of a cathode ray tube 1 is positioned below the frame 13. A plurality of heating means for flaming and welding the neck la of the cathode ray tube 1 mounted on the frame 13 are positioned around the index table 11. As illustrated in Figures 3 and 4, the heating means consists of two opposing nozzles 15 and 15 and two opposing nozzles 16 and 16 surrounding the neck la of the cathode ray tube spaced at a predetermined distance therefrom, and supporters 14a and 14b positioned around the index table 11 to support the nozzles.The four nozzles are paired as first nozzles 15 and 15, and second nozzles 16 and 16 which are positioned opposite one another and burn varying amounts of gases, i.e., fuel and oxygen, in order to flame the neck of the cathode ray tubes with the prescribed amount of heat energy according to the size of the cathode ray tubes 1 mounted on the frame 13. These nozzle pairs 15,15 and 16,16 are respectively connected to a pair of fuel supply lines 15a and 16a, and a pair of oxygen supply lines 15b and 16b. The fuel supply lines 15a and 16a, and the oxygen supply lines 15b and 16b respectively branch off into main lines 15c, 16c, 15d and 16d fed a large amount of fuel and oxygen, and auxiliary lines 15c', 16c', 15d' and 16d' through which flow a lesser amount of fuel and oxygen. The main lines 15c, 16c, 15d, and 16d, and the auxiliary lines 15c', 16c', 15d' and 16d' are respectively equipped with solenoid valves Sla, S2a, S3a and S4a for opening and closing the lines, and manual control valves Slb, S2b, S3b and S4b for presetting the amount of the gas flow going through each line. The solenoid valves Sla, S2a, S3a and S4a installed at the main lines 15c, 16c, 15d and 16d and the auxiliary lines 15c', 16c', 15d' and 16d' for controlling the gas supply are connected to control means (not shown) to be selectively operated according to the size of cathode ray tube mounted on the frame. The control means is connected to detecting means (not shown) provided at a location around the index table and, thus, receives signals detected in response to the size of the cathode ray tubes conveyed by the index table 11.

The operation of the sealing apparatus of the electron gun of the cathode ray tube according to the present invention constructed in the aforesaid manner will be described below.

In the initial state of the operation, the control means closes all solenoid valves Sla and S3a of each main line 15c, 16c, 15d, and 16d, in the meantime, opens the solenoid valves S2a and S4a of each auxiliary line 15c', 16c' 15d', and 16d', in the oxygen supply lines 15b and 16b of the first and second nozzles 15 and 16 fixedly positioned around of the index table 11 by means of the support rod 14, so that a sunk flame in readiness state, i.e., pilot flame, is ejected from each nozzle 15,15 and 16,16.

Under the condition that the pilot flame in readiness state is ejected from the first and second nozzles 15 and 16, if the cathode ray tube 1 and the electron gun mount assembly 2 which will be inserted into the cathode ray tube 1 are mounted by the frame 13 rotating with the index table 11 periodically turning by prescribed angles, and by the support rod 12 positioned below the frame, the detecting means provided in the conveyer line of the components detects the state of mounting the components and the size of the cathode ray tube 1, thereby transmitting the detected signals to the control means.

In response to the signals generated from the detecting means, the control means operates the solenoid valves of a pair of nozzles out of the oppositely arranged two pairs of nozzles, whose flame sizes are differently adjusted by the fuel supply control valves. Therefore, intense flame is ejected from the selected pair of nozzles among the nozzles ejecting pilot flame at readiness state, so that the neck of the cathode ray tube and the stem of the electron gun mount assembly housed into the neck are fixedly welded.

In more detail, for example, if the first nozzles are selected to eject intense flame by the control means, the solenoid valve S4a installed at each auxiliary line 15c' and 15d' of the fuel supply line 15a and oxygen supply line 15b connected to the first nozzles 15 is closed, and the solenoid valve S3a installed at each main line 15c and 15d is opened to eject an adjusted flame which is enough to heat the neck la of the cathode ray tube 1.

Therefore, The first nozzles 15 are ejecting flame to fixedly weld the neck portion la of the cathode ray tube 1 and the stem of the electron gun mount assembly 2 which are periodically conveyed by the index table 11.

Meanwhile, the second nozzles 16 continue to continuously eject the pilot flame of the readiness state without ejecting intense flame. Then, if another cathode ray tube and the electron gun mount assembly of different sizes are mounted on the frame, the detecting means and the control means closes the solenoid valve S3a of respective main lines 15c and 15d of the fuel supply line 15a and oxygen supply line 15b of the first nozzles 15, and opens the solenoid valve S4a of the auxiliary lines 15c' and 15d', and this brings the result that the first nozzles 15 and 15 eject the pilot flame of the readiness state and the second nozzles 16 and 16 eject flame by being controlled in accordance with the foregoing operational steps in order to heat sufficiently the neck and the electron gun mount assembly of the cathode ray tube, thereby welding the neck and the electron gun mount assembly of the cathode ray tube.

Because the sealing apparatus for the electron gun of the cathode ray tube according to the present invention is advantageous in that the electron gun can be selectively welded for sealing by adjusting the nozzles according to the size of the cathode ray tubes, sealing work for the electron gun of the cathode ray tube is compatibly carried out, and, further, the fuel consumption and the inferiority rate of the cathode ray tubes can be greatly lowered, and as a result, productivity can be improved.

Claims (2)

1. A sealing apparatus for an electron gun of a cathode ray tube, comprising an index table for periodically turning by prescribed angles; a plurality of frames on the marginal edge of said index table, each for mounting a cathode ray tube; a plurality of support rods below said frames each for supporting an electron gun mount assembly inserted in the cathode ray tube; and a plurality of heating means having a plurality of nozzles for providing a flame to weld the neck portions of the cathode ray tubes, wherein said nozzles are differentiated for ejecting flame for heating the neck of a plurality of cathode ray tube sizes by adjusting the calorific value of the flame, and said sealing apparatus further comprises:: a plurality'of fuel supply lines and a plurality of oxygen supply lines connected to the nozzles of said plurality of heating means, respectively, which lines comprise main lines for discharging fuel and oxygen and auxiliary lines for discharging an amount of fuel and oxygen which is less than that discharged by said main lines; a plurality of valve means each located in said main lines and said auxiliary lines for closing and opening said complex fuel supply lines and controlling the flow of fuel and oxygen; a detecting means arranged adjacent the turning route of the index table for detecting the size of the cathode ray tubes mounted on said frames; and a control means for controlling said closing and opening valve means installed at said supply lines to adjust the amount of flame ejected from said nozzles in response to signals detected by said detecting means.

2. A sealing apparatus for an electron gun of cathode ray tube substantially as hereinbefore described with references to Figure 3 to 4 of the accompanying drawings.