KR100586200B1 - Thermal fuse - Google Patents

Abstract

In the present invention, when an abnormal overheating of the device is caused, the movable member, which is installed at one side and presses the movable terminal, is melted so that the movable terminal that has formed the contact with the lead terminal is retreated by the elastic recovery force of the spring, The present invention relates to a structure in which the safety of a thermal fuse is improved by providing a receiving hole in an insulating bracket for holding a lead terminal and holding the end portion of the lead terminal in the receiving hole, The present invention provides a thermal fuse that improves safety by preventing an abnormal conductive phenomenon between two springs.

Description

[0001] THERMAL FUSE [0002] FIELD OF THE INVENTION [0003]

FIG. 1 is a cross-sectional view showing the entire structure of a conventional thermal fuse,

FIG. 2 shows an incision of a thermal fuse according to a preferred embodiment of the present invention,

3A and 3B are sectional views for explaining the action of a thermal fuse according to a preferred embodiment of the present invention. FIG. 3A shows a state in which a lead terminal and a movable terminal are in contact with each other, FIG. 3B shows a state in which a lead terminal and a movable terminal are short- Respectively,

4 is a perspective view of a movable terminal used in a thermal fuse according to the present invention.

DESCRIPTION OF THE REFERENCE SYMBOLS

1. Thermal fuse 10. Cylindrical case

11. Connection terminal 20. Available terminal

30. Insulation bracket 31. Receiver

40. Lead terminal 40a. End

50. Operation terminal 51. Movable body

51a. Protruding end 51b. Pressure stage

52. Annular bushing 52a. Contact point

61. First spring 62. Second spring

 70. Mold

More particularly, the present invention relates to a thermal fuse, and more particularly to a thermal fuse, wherein when a fuse installed on one of the fuses is melted when the device is abnormally overheated, the movable terminal, which has formed the contact with the lead terminal, is retreated by the elastic recovery force of the spring, And more particularly, to a structure in which safety is improved in a thermal fuse in which a circuit is cut off due to overheating.

Generally, a thermal fuse is installed in an electric heating device such as an iron or an electric rice cooker to prevent damage to the device due to abnormal overheating.

1, the thermal fuse 100 generally includes, on both sides of the accommodation space inside the cylindrical case 101, a lead terminal 102 fixed by an insulating bracket 103 and a solder terminal 102 fixed by the insulation bracket 103, And a movable terminal 105 for connecting the cylindrical case 101 and the end portion 102a of the lead terminal 102 to each other to conduct electric current is provided in the spaced space, A pair of springs 105 and 106 fixed to the insulating bracket 103 and the movable body 104 are provided on the front and rear sides of the movable terminal 105 so that the movable terminal 105 105).

In the conventional thermal fuse 100 constructed as described above, when abnormal overheating of the device occurs, the movable body 104 housed in the cylindrical case 101 melts and is thus supported by the movable body 104, 105 of the second spring 107 that has been retracted from the rear side is lost. When the resilient force of the second spring 107 is lost, the movable terminal 105 is retracted by the resilient force of the first spring 106 which is treading on the front surface of the movable terminal 105, The lead terminal 105 and the lead terminal 102 are spaced apart from each other, thereby blocking the circuit.

In the conventional thermal fuse 100 as described above, the insulating bracket 103 serves to fix the tip end of the lead terminal 102 to the case 101, but the end 102a of the lead terminal is connected to the insulating bracket And a first spring 106 for elastically supporting the front surface of the movable terminal 105 surrounds the exposed end portion 102a.

Thus, when the end portion 102a of the lead terminal 102 or the first spring 106 surrounding the lead terminal 102 is deformed or the melted soluble body flows into the first spring 106 side, A spark is generated between the end portion 102a of the lead terminal 102 and the first spring 106 to cause a contact between the end portion 102a of the lead terminal 102 and the first spring 106 So that a current is conducted between the lead terminal 102 and the first spring 106 or a current can be conducted through the melted solenoid. In this case, the function of the thermal fuse "interruption of current in abnormal overheating" is lost, which may cause defects.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to solve the above-mentioned problems by providing an accommodating portion recessed in an insulative bracket for securing a lead terminal and accommodating the end portion of the lead terminal in the accommodating portion, The present invention provides a thermal fuse having improved safety that prevents abnormal electrical conduction between two springs.

The above object is achieved by the following constitution provided in the present invention.

According to the present invention, there is provided a thermal fuse having improved safety,

A cylindrical case of a conductive material to which connection terminals are connected;

An insulating bracket installed at one side of the inner space of the case and having a hollow receiving port;

A soluble body which is installed on the outside of the inner space of the case and is melted when overheated;

A lead terminal accommodated in the receiving port of the insulating bracket and disconnected from the case;

And a protruding end which is provided between the movable member and the insulating bracket of the case, and the protruding end forms a contact point with the end of the lead terminal in the receiving hole of the insulating bracket, A movable terminal that bridges between inner walls of the case to conduct electric current; And

A first spring having one end supported by the insulating bracket and pressed against the front surface of the movable terminal, and a second spring supported at one end by the movable body to pressurize and force the rear surface of the movable terminal;

The movable terminal is retracted by the restoring force of the first spring, and the end of the lead terminal and the protruding end of the usable terminal are separated from each other by the restoring force of the first spring, thereby blocking the conduction of the current .

Preferably, the movable terminal of the thermal fuse according to the present invention further includes: an annular bush having a plurality of contact pieces formed in an annular shape in contact with the inner wall of the cylindrical case; And a movable body having a protruding end are integrally formed. On the other hand, the movable body and the annular bush of the movable terminal may be formed by plating silver on the surface of the copper molding with excellent conductivity or by self-silver.

Preferably, the space between the insulating bracket provided on one side of the cylindrical case and the inner wall of the case is molded with an insulating material so as to exhibit a stable airtight effect.

Hereinafter, a thermal fuse provided as a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a sectional view of a thermal fuse with improved safety provided as a preferred embodiment of the present invention. FIGS. 3a and 3b are cross-sectional views illustrating the operation of a thermal fuse according to a preferred embodiment of the present invention. Fig. 3A shows a state in which the lead terminal is in contact with the movable terminal, and Fig. 3B shows a state in which the lead terminal and the movable terminal are short-circuited.

Referring to the drawings, a thermal fuse 1 with improved safety provided as a preferred embodiment of the present invention is provided on both sides of the internal space of a cylindrical case 10 formed of or plated with a metallic material, such as silver, An insulating bracket 30 to which the end portion 40a of the terminal 40 is fixed and a useable body 20 to be melted when abnormal overheating are respectively installed and the lead terminals 40 And the movable terminal 50 that conducts the cylindrical case 10 are provided.

One end of the cylindrical case 10 is opened so that the insulating bracket 30 having the end portion 40a of the lead terminal 40 fixed to the opened end thereof is fixed by molding 70, Thereby forming a sealed structure. On the opposite side to the lead terminal 40, a connection terminal for connecting the thermal fuse 1 according to the present invention and the thermal fuse is formed.

The front surface of the movable terminal 50 is resiliently biased by a first spring 61 whose one end is supported by the distal end of the insulating bracket 30 and the rear surface is supported by a second spring (Not shown). The resilient force of the second spring 62 protruding from the back surface of the movable terminal 50 is greater than the elastic force of the first spring 61 protruding from the front surface of the movable terminal 50, The second spring 62 has a tendency to advance in the direction of the insulating bracket 30 due to the elastic force of the second spring 62.

The end of the lead terminal 40 is exposed to the outside of the insulating bracket 30 in the receiving hole 31. The insulating bracket 30 is formed in a shape of a hollow, So that the end portion 40a of the lead terminal 40 and the first spring 61 supporting the front surface of the movable terminal 50 are completely separated from each other by the insulating bracket 30.

When the end portion 40a of the lead terminal 40 and the first spring 61 protruding from the front surface of the movable terminal 50 are completely separated from each other, the end portion of the conventional lead terminal and the deformation or current of the first spring An arc is generated between the end of the lead terminal and the first spring due to over supply or the like and an abnormal phenomenon that a contact point is formed between the end of the lead terminal and the first spring can be prevented.

4 shows a perspective view showing a state in which only the movable terminal 50 used in the thermal fuse 1 according to the present embodiment is separated. Referring to FIG. 4, the movable terminal 50 is arranged on the front side A movable body 51 provided with a protruding end 51a and forming a contact with an end portion 40a of the lead terminal 40 accommodated in the accommodating portion 31 of the insulating bracket 30; And an annular bush 52 having a plurality of annular bushes 52 arranged in an annular shape are integrally combined with each other. Here, the contact pieces 52a of the annular bush 52 expand the contact area with the inner wall of the cylindrical case 10 and have an elastic force so as to maintain an elastic bonding state on the inner wall of the cylindrical case 10 And a pressing end 51b having a large area is formed on the rear side of the movable body 51 so that the movable body 51 can be stably stood by the second spring 62 which will be described later. .

Here, the movable body 51 of the movable terminal 50 and the annular bush 52 fixed to the movable body 50 are made of a silver material having excellent conductivity. In order to reduce the cost, the annular bush 52, The movable body 51 may be made of a copper mold and plated with silver having a high electrical conductivity.

The movable terminal 50 thus formed has a state in which the projecting end 51a of the front surface enters into the receiving port 31 provided in the insulating bracket 30 and forms a contact point with the end 40a of the lead terminal 40 And is fixed by the biasing force of the second spring 62.

3A, the movable terminal 50 is electrically connected to the insulating bracket 30 (see FIG. 3A) by the elastic force of the second spring 62 which rides on the back surface of the movable terminal 50. At this time, The protruding end 51a of the movable terminal 50 forms a contact point with the end 40a of the lead terminal 40 accommodated in the insulating bracket 30. [

When the end portion 40a of the lead terminal 40 and the movable terminal 50 form a contact point, the current applied through the lead terminal 40a flows along the movable terminal 50 to the cylindrical case 10, And is applied to the device through the connection terminal 11.

However, if the thermal fuse 1 is abnormally overheated, the movable body 10 supporting the second spring 62 is melted as shown in FIG. 3B, so that even if the second spring 62 is elastically restored, the movable terminal 50 The resilient force by the second spring 62 applied to the back surface of the movable terminal 50 is lost. Accordingly, the first spring 61, which is in contact with the front surface of the movable terminal 50, is retracted by the elastic force of the second spring 62, and the movable terminal 50 is retracted.

As a result, the end portion 40a of the lead terminal 40 accommodated in the insulating bracket 30 and the movable terminal 50 are spaced apart from each other to form a non-contact state, and the current which is conducted between them is cut off, And acts as a thermal fuse.

As described above, the thermal fuse according to the present invention allows the end portion of the lead terminal exposed in the conventional insulation bracket to be received in the insulation bracket.

When the lead terminals are accommodated in the insulating bracket, the movable terminals are maintained in a completely separated state from the first springs which are treading on the front surfaces of the movable terminals. Therefore, due to the deformation of the end portions of the lead terminals, A problem arises in the prior art that a spark is generated between the end of the lead terminal and the first spring and a contact point is formed between the end of the lead terminal and the first spring.

Claims (4)

A cylindrical case of a conductive material to which connection terminals are connected; An insulating bracket installed at one side of the inner space of the case and having a hollow receiving port; A soluble body which is installed on the outside of the inner space of the case and is melted when overheated; A lead terminal accommodated in the receiving port of the insulating bracket and disconnected from the case; And a protruding end which is provided between the movable member and the insulating bracket of the case, and the protruding end forms a contact point with the end of the lead terminal in the receiving hole of the insulating bracket, A movable terminal that bridges between inner walls of the case to conduct electric current; And A first spring having one end supported by the insulating bracket to press-fit the front surface of the movable terminal, and a second spring having one end supported by the movable body to pressurize and press the rear surface of the movable terminal; Wherein when the movable member is melted by overheating, the movable terminal is retracted by the restoring force of the first spring, so that the end of the lead terminal and the protruding end of the usable terminal are separated from each other, This enhanced thermal fuse. The connector according to claim 1, An annular bush having a plurality of contact pieces formed in an annular shape in contact with an inner wall of the cylindrical case, and a movable body having a protruding end protruded from the front side so as to be received in the receiving hole of the insulating bracket are integrated. Thermal fuse.  3. The thermal fuse according to claim 1 or 2, wherein the movable terminal is plated with a silver material having excellent conductivity on the surface of the copper mold, or is formed of a silver material. 2. The thermal fuse according to claim 1, wherein the space between the insulating bracket provided on one side of the cylindrical case and the inner wall of the case is molded with an insulating material so that a stable airtight effect is exhibited.

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