JPS6244415Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a reed switch, that is, an enclosed switch,
In particular, the present invention relates to a heating sealing device used in the manufacturing process (sealing of glass tubes) of mercury wet and dry switches, and relates to a glass tube sealing heater for an enclosed switch as a resistance heating element in the device.

FIG. 1 is a side view showing the main structure of the switch when it is sealed, and the outline of the process will be explained with reference to the drawings.

In the figure, 1 forming the switch member is a glass tube;
2 and 3 are lead pieces each made of a magnetic material; the upper lead piece 2 shown in the figure is a member on the fixed side, and the lower lead piece 3 is a member on the movable side, and the contact facing parts 4 of these lead pieces have a predetermined overlap and a gap between the contacts. This is the contact forming part that provides.

The movable lead piece 3 is connected at its center to a spring 5, and the spring is further fixed to the lower movable side terminal 6 by welding or the like. Reference numeral 7 denotes an auxiliary member made of a magnetic material, which increases the magnetic sensitivity of the switch.

The glass tube 1, the fixed reed piece 2, and the movable reed assemblies 3, 5, 6, and 7 are placed in the illustrated arrangement within the glass tube.

In this case, the glass tube 1 is a chuck 10, and the reed piece 2 and the movable lead assembly are a clamper 8.
and held at 9. The chuck 10 and the clampers 8, 9 are part of the sealing device.

The cylindrical parts of the upper and lower heaters 11 are arranged at the upper and lower ends of the glass tube 1 so as to surround the glass tube 1, and the upper and lower clampers 8 and 9 are used to connect the lead pieces 2 and 3 in the glass tube 1 to predetermined contact points. A facing portion 4 having a gap and an overlap is provided. In this state, the upper end of the glass tube 1 is sealed by the upper heater 11, and then the lower heater 1
1. Seal the lower end of the glass tube.

A perspective view of one of the upper and lower heaters 11 forming the seal is shown in FIG.

Conventionally, such a sealed heater is made by bending and forming a band-shaped resistance material of an appropriate width to form the illustrated cylindrical portion 12 and heater power supply terminal portions 13 and 13' (13 and 13' are connected to the power supply terminal of the sealing device). . Cylindrical part 12
The movable terminal 6, lead piece 2, and glass tube 1 are inserted into the cylinder (see Fig. 1).

The problem with such a sealed heater is that the current applied during heating generates an axial magnetic field (in the direction of the arrow in the figure), and this magnetic field disturbs the gap in the contact opposing part 4 that was applied before sealing, causing the switch characteristics to change. The purpose of this is to provide variation in the results.

Especially in the lower sealing process, the leaf spring 5 is placed near the sealing position.
Because there is a welding point (spring support point), when heating current is applied to the lower heater 11, the generated magnetic field attracts the lead piece 3 to the lead piece 2 side, and the spring 5 is sealed with glass in a bent state. Therefore, there is a drawback that the normal support of the spring 5 is easily deformed.

The purpose of the present invention is to eliminate the above-mentioned problems, and to provide a glass tube sealed heater for a sealed switch that can uniformize and stabilize the switch characteristics.

Its unique feature is that in the device for heat-sealing the glass tube of an encapsulated switch, a slit is cut in the center of the band-shaped resistor element so that only the extreme end remains, forming a strip that is divided into upper and lower parts. This is a glass tube sealed heater for an enclosed switch in which one end with the uncut end is bent to form a cylindrical part to form a non-inductive seal.

An embodiment of the present invention shown in FIG. 3 will be described below. Figure A shows a front view of a strip-shaped resistance element body, and Figure B shows a perspective view of Figure A by bending and forming it into a sealed heater.

The illustrated band-shaped punched resistance element 15 has a narrow groove or slit 14 approximately in the center thereof. At the extreme end thereof, an uncut portion 16 is formed which corresponds to a current turning portion and has the same resistance value as the strip portion that is divided into slits. This resistance element 15
Figure B shows a sealed heater with a cylindrical portion formed by bending one end of the heater. Note that the end portion of the illustrated cylindrical portion, that is, the uncut portion 16 does not contact the resistive element 15 itself.

With such a sealed heater structure, the magnetic field generation direction of the heating current will be completely opposite in the strips 17 and 17', the magnetic field generation in the cylindrical portion will be canceled, and the magnetic field will not act on the lead piece at the cylindrical shaft position. I won't give it. That is, the inconveniences caused by conventional cylindrical heaters are eliminated.

At this time, in order to obtain the same power supply heating conditions as in the conventional method when molding the present sealed heater, the thickness of the resistive element plate may be made at least twice as thick.

If the heat-sealing heater is applied to sealing the glass tube of an enclosed switch, it will not generate a magnetic field and will not cause contact gap disturbance, resulting in uniform switch characteristics.
It is possible to achieve stability, thereby improving the switch yield.

[Brief explanation of drawings]

FIG. 1 is a side view showing the main parts of the heat sealing device according to the present invention, and FIG. 2 is a perspective view of a conventional sealing heater.
FIG. 3A is a front view of the band-shaped resistance element body before forming the sealed heater according to the present invention, and FIG. 3B is a perspective view of the sealed heater of the present invention after being bent and formed. DESCRIPTION OF SYMBOLS 11... Conventional sealed heater, 14... Slit, 15... Band-shaped resistance element body, 16... Uncut portion, 17, 17'... Divided strip.

Claims (1)

[Scope of utility model registration request] A cylindrical part formed by bending one end of a band-shaped resistance element so that the ends thereof do not touch is arranged so as to surround the outer periphery of the upper and lower ends of a glass tube, and is made of a magnetic material inserted into the glass tube. In a sealed heater that heats and seals the upper and lower ends of the glass tube so that a plurality of lead pieces form a predetermined overlap and a gap between the contacts, the slit that divides the heater into upper and lower parts is formed at the end of the band-shaped part that is not bent. 1. A glass tube sealed heater for an enclosed switch, characterized in that the glass tube sealed heater is provided from the cylindrical part to the cylindrical part, and only the outermost end of the cylindrical part is a divided upper and lower connecting part.