JPS5856205B2 - Reed switch glass tube sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for sealing both ends of a glass tube of a reed switch.

A reed switch is made by inserting a pair of thin conductive and soft magnetic wires called reed pieces into a glass tube from both ends of the glass tube, with the tips of the wires facing each other with a small gap between them and crushing them flat to form a contact point. Further, both ends of the glass tube are heat-sealed to airtightly seal the lead piece at these ends, and air or an inert gas is then sealed inside the glass tube.

By the way, there are various methods for sealing the ends of the glass tube of this reed switch, but generally a pair of reed pieces are inserted from both ends of the glass tube, and then heat is applied to the ends of the glass tube to soften and melt them. let

The conventional method for applying this heat is to use a band heater made by bending a heat-resistant metal band such as platinum-rhodium to cover the glass tube, but this band heater has a short lifespan and does not come in contact with surrounding objects. Since deformation may occur, it is troublesome to manually correct the deformation, and there are also drawbacks such as the constituent metal scattering from the band heater and adhering to the glass tube.

Therefore, a method has now been changed to using an infrared lamp instead of a heater, and this reed switch sealing method is shown in FIGS. 1 and 2.

1 and 2, 1 is a lead piece, 2 is a glass tube, 3 is a reflecting mirror, 4 is a mirror on the light source side, and 5 is an infrared light source such as an infrared lamp.

The reflective square 3 is approximately Ω-shaped and covers half the circumference of the glass tube 20.

The light source side mirror 4 forms a hollow paraboloid of rotation, and the light source 5 is placed at its focal point.

In this device, infrared rays from a light source 5 are focused by a mirror 4 and irradiated onto the tube end of the glass tube 2, and the back side of the tube end is focused and irradiated by a □ sheath 3 to soften and melt the tube end. However, with the current equipment, it is difficult to narrow the focus, and the shape of the softened weld at the end of the glass tube collapses to one side, making it asymmetrical, and the shape is not as good as that with conventional band heaters.

This is especially true when reed switches become smaller and the diameter of the glass tube becomes smaller.Since the infrared lamp 5 is not replaced even if the tube diameter becomes smaller, the light condensing power is 1X, which is determined by the size of the filament and other factors. This tends to result in defective fusion shapes and the sealing portion tends to be too large.

Therefore, even though relatively large reed switches use the infrared lamp method, the reality is that small reed switches use the conventional band heater method.

When heating and fusing the ends of small glass tubes, impurities may scatter from the heated portion.1. There is also the problem that this adheres to the mirror and deteriorates the reflectance.

In view of these points, the present invention has good light condensing properties, the light condensing degree can be easily changed according to the size of the object to be sealed, and it is less susceptible to the influence of flying objects from the glass tube. The present invention aims to provide an infrared sealing device.

The present invention will be described in detail below with reference to the embodiments shown in FIGS. 3 to 5.

In the present invention, the reflecting mirror is formed into a ring shape as shown in FIG.

This reflecting mirror 10 has a reflecting surface 11 having a conical shape,
It is inserted into the glass tube with the larger inner diameter facing toward the incident light side.

The light source 5 and the light source side mirror 4 are placed in front of the glass tube along the tube axis direction of the glass tube 2 as shown in FIG.
The infrared rays from the mirror irradiate the mirror 10 as parallel lines as shown by the arrows, and are reflected by the mirror to irradiate the end of the glass tube 2.

In this method, as in the method shown in Fig. 1, the end of the glass tube receives direct light from the infrared lamp 5, reflected light from the light source side
Light that passes through the glass tube and is reflected by the reflective mirror 3 to illuminate the back side of the end of the glass tube, light from an infrared lamp and light source side mirror 4 is reflected by the mirror 3, and illuminates the side surface of the end of the glass tube, etc. Compared to methods that heat with various types of light, this reflective mirror uses infrared rays from the light source directly to the button, receives it on a ring-shaped reflective mirror, and reflects it on the mirror, uniformly irradiating the entire circumference of the end of the glass tube. 10 operates like a band heater and uniformly heats the end of the glass tube in the circumferential direction.

As a result, the sealing shape of the end of the glass tube is good.

In addition, the heating length of the end of the glass tube can be easily changed by changing the position of the reflector with respect to the glass tube and/or the angle of inclination α of the reflective surface 11. The length of the section can be adjusted to the desired value.

Therefore, for example, if several types of reflection mirrors 10 with different inclination angles α of the reflection surface 11 are prepared in advance, and the reflection mirrors are replaced according to the size of the reed switch glass tube, the seal that matches the glass tube size can be used. It is convenient because the stop portion can be easily obtained.

In FIG. 1, since changing the sealing length requires changing the lamp size and the curvature of the reflecting mirror, the method of the present invention is extremely advantageous compared to the above methods.

In the method of the present invention, the light source needs to be placed above and below the glass tube in the axial direction of the tube, rather than on the side, but it is possible to take up this space by adjusting the button in the manufacturing process.

When sealing the glass tube, the glass tube 2 is held by the upper clamper 15 as shown in FIG. 5, and the lead piece 1 is held by the lower clamper 16. It moves through the process.

Then, the reflection mirror 15 is fitted into the upper end of the glass tube 2 at a predetermined position, and a coil (not shown) is excited to generate a magnetic field, and in this state, the other lead piece 1 is inserted from above and into the lower lead piece. It is attracted toward the contact portion by the magnetic field, and is erected and held in a vertical position as shown in the figure.

Heating and sealing with an infrared lamp is performed in this state, first sealing the top end of the glass tube, then the bottom end, then deenergizing the coil to cut off the magnetic field, and while it is in the softened state, the lower clamper is closed. 16 or by striking the reed pieces with an operating rod to create a gap between the reed pieces.

The upper and lower ends of the glass tube can be sealed by providing windows on the upper and lower surfaces of the chamber and correspondingly installing light sources on the upper and lower parts, respectively, or by providing the light source and windows only on the upper part. , the reflective □ mirror may be shifted to perform the lower sealing on top.

In this case, it is convenient to divide the reflecting mirror into two parts and peel them off to avoid being hit by a clamper.

Further, the glass tube may be sealed in a horizontal state, and in this case, the light source position can be horizontal as shown in FIG.

When the end of the glass tube is sealed by heating, potassium (K) contained in the glass tube evaporates and scatters, which adheres to the reflective mirror and reduces the reflectance.

This removal is troublesome, so it is necessary to remove potassium as much as possible.
However, it is difficult to completely remove potassium.

In this regard, if the annular reflecting mirror of the present invention is used, the amount of potassium deposition can be reduced because the reflecting surface expands upward.

As explained in detail above, according to the present invention, a heating method that has the advantages of both conventional infrared heating and band heater heating can be obtained, and a ring-shaped heating method that makes it easy to balance direct light and reflected light. Due to its symmetry, it is easy to make the sealing shape uniform, and the sealing section can be easily adjusted by changing the inclination angle of the mirror reflection surface and/or the position of the mirror relative to the glass tube. The benefits of homogeneous species can be reduced.

[Brief explanation of the drawing]

Figures 1 and 2 are perspective views and sectional views illustrating a conventional sealing method using lamp heating, and Figures 3, 4, and 5 are main parts showing an embodiment of the present invention. They are a perspective view, a sectional view, and a perspective view. 1... Lead piece, 2... Glass tube, 3, 4... Mirror, 5... Infrared lamp, 10... Annular reflecting mirror 15° 16... Clamper.

Claims (1)

[Scope of Claims] 1. An annular reflecting mirror having a conical reflecting surface expanded toward the incident light side into which the glass tube end of the reed switch is fitted, and a light source that projects parallel infrared rays onto the reflecting mirror. A glass tube sealing device for a reed switch characterized by: 2. A glass tube sealing device for a reed switch according to claim 1, comprising a plurality of annular reflective squares whose inclination angles of reflective surfaces are changed depending on the sealing length.