JPS6126769Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is installed to the power terminal of an automobile cigarette lighter, and prevents thermal deformation, deterioration, or combustion of the mounting part due to abnormal overheating of the heat generating part that is induced when the cigarette lighter malfunctions. This invention relates to a cigarette lighter temperature fuse device for an automobile that attempts to prevent this phenomenon from occurring.

Conventionally, when using a cigarette lighter for an automobile, when the knob is pushed in, a hot wire provided in the cigarette lighter is energized to red-hot, and after a certain period of time, the knob pops out. However, malfunctions may occur due to foreign matter adhering to the cigarette lighter, or if the socket side of the cigarette lighter is replaced with a commercial product other than a cigarette lighter,
For example, when used as a power socket for an automobile vacuum cleaner, the knob could become incapable of popping out, and the plastic cigarette lighter attachment part could catch fire, causing a fire.

To deal with such problems, there is a known device that cuts off the power by installing a temperature fuse, for example as shown in FIG. 1 or 2, if the cigarette lighter overheats above a predetermined temperature. Each of them had drawbacks in terms of performance, price, etc. That is, in the configuration shown in FIG.
Inserting another terminal 4 having a flange 4a on the other end of the flame-retardant thermoplastic resin case 3 screwed onto the power supply terminal 2 of the cigarette lighter 1;
A spring 5 is wound between the flange 4a and the inner wall of the case so that the terminal 2 is normally kept in an electrically energized state, and when the cigarette lighter 1 overheats to a predetermined temperature or higher, The threaded part of the case 3 that receives the heat from the power supply terminal 2 melts, and in cooperation with the spring 5, the case 3 separates from the terminal 2 along with the other terminal 4 and the spring 5, and the power supply from the power supply 6 is interrupted. However, this device has a drawback in that the time from overheating to decomposition cannot be specified within a predetermined period of time. There are two cases in which the lead wire 7 connected to another terminal 4 is in a natural state where its own weight is applied to the other terminal 4, and on the other hand, the lead wire 7 is connected to the other terminal 4 by some means, such as a clamper. There was a difference in the time required for the case to be released when the case was held close to , that is, it took a long time in the latter case, and there were cases where the case did not break within the desired time.

In addition, in the configuration shown in FIG. 2, the nut member 10 is fixed to the other end surface of the nut member 10 which is screwed and fixed to the terminal shaft 9 of the power source of the cigarette lighter 8, and the nut member 10 is fixed at a constant temperature by conductive heat from the cigarette lighter 8. The terminal 11 is formed of a temperature fuse element made of solder or the like, for example, and the terminal 11 is formed of a temperature fuse element that melts as described above to cut off the power supply from the power source 6. In this configuration, the terminal 11 melts due to overheating, and the connection member 10 If it detaches and falls, the fused terminal 11 is exposed at the tip of the lead wire 7, so it may come into contact with a metal part on the vehicle side, causing secondary problems such as a short circuit accident of the power source 6. It had drawbacks.

The present invention eliminates the above-mentioned drawbacks, and has a structure that can be manufactured more reliably, safely, and at a lower cost.In other words, when the cigarette lighter overheats, the device reliably turns off the power supply within a predetermined period of time. It is an object of the present invention to provide a temperature fuse device for a cigarette lighter for an automobile, which is provided with a disconnection point and does not require the lead wire to come off.

Hereinafter, a preferred embodiment of the automobile cigarette lighter temperature fuse device according to the present invention will be described in detail with reference to FIGS. 3, 4, 5, and 6.

Reference numeral 12 denotes a socket body of a cigarette lighter, and a shaft 15 to which a bimetal electrode 14 is fixed through an insulator 13 protrudes from an end surface forming the inner bottom of the socket body 12, and an insulating washer 16.
A bimetallic electrode 14 is attached and fixed to the socket main body 12 via a spring washer 17 and a terminal 18 serving as a connecting member.

Reference numeral 19 denotes a case of a temperature fuse device, which is made of a flame-retardant thermoplastic resin, such as polypropylene, which melts at a predetermined superheating temperature. The case is threaded on the inside, and grooves 19a are provided on the circumferential wall of the threaded wall to face each other, and one end is screwed into the outer threaded portion of the terminal 18. A hole 19b into which the connection terminal 20 is inserted is bored in the center of the other end surface. 20 is a connection terminal connected to the lead wire 7 from the power source 6.

Reference numeral 21 denotes an elastic contact piece, which is made of an elastic and conductive spring material, such as phosphor bronze, and is formed into a U-shape. Contact points 21a are provided at both ends, and the center of the base is fixed to the connection terminal 20 by caulking or the like, and the elastic contact piece 21 is auxiliary assembled.
and the connecting terminal 20 to the case 19. As shown in FIG. 3, the elastic contact piece 21 is attached to the groove 19a, and the connecting terminal 20 is inserted into the hole 19b. An insulator 22 is interposed between the end face of the terminal 18 and the base of the elastic contact piece 21, and maintains insulation so that no electrical connection is made at the end face of the terminal 18. Therefore, when the case 19 is screwed onto the terminal 18, the contact 21a of the elastic contact piece 21 connects to the tapered surface 18a provided at the base of the outer peripheral screw of the terminal 18, and the protrusion provided in the groove 19a of the case 19. The contact 21a and the terminal 18 are brought into contact by pressing with the surface 19c, and the electrical connection between the contact 21a and the terminal 18 is maintained.

Reference numeral 23 denotes an outer case, which fixes the socket main body 12 of the cigarette lighter to the mounting portion on the vehicle side. 24 is a hot wire cap at the tip of the plug side, and a hot wire (not shown) is installed inside the hot wire cap.

Next, the effect will be explained.

Now, in the cigarette lighter shown in FIG.
When engaged with the bimetallic electrode 14, the power source 6
The current from the positive electrode of the connecting terminal 20, elastic contact piece 21,
Terminal 18, shaft 15, and bimetal electrode 1
4 through the hot wire cap 24 on the plug side, the hot wire, etc., further flows to the socket body 12, the outer case 23, and the negative electrode of the power source 6, and the hot wire on the plug side is red-hot, and when it reaches a predetermined temperature within a predetermined time, The engagement of the bimetal electrode 14 is released, and the plug side knob is
Although it returns to the OFF state, under such normal operating conditions, the terminal 18 is disconnected from the hot wire.
Thermal conduction to various parts such as the cigarette lighter mounting part does not cause any abnormality, that is, the temperature does not rise above a predetermined temperature.

However, for some reason, the engagement between the bimetal electrode and the plug-side hot wire cap 24 is not released even after a predetermined period of time has passed, and if the power supply 6 continues, the temperature of the terminal 18 will increase due to heat conduction from the hot wire. gradually rises, and when the abnormal temperature reaches a specified value, for example 150°C to 170°C in the example, the case 19 made of flame-retardant thermoplastic resin softens and melts due to heat conduction from the terminal 18 and the elastic contact piece. In the process of this change, the outer wall portion of the groove 19a in which the elastic contact piece 21 having a small amount of heat melt is attached is deformed or damaged by the reaction force of the elastic contact piece 21, as shown in FIG. Therefore, the contact point 2 of the elastic contact piece 21
1a is separated from the tapered surface of the terminal 18.

In this way, the current from the power source 6 is cut off at the contact point 21a of the elastic contact piece 21, and the power to the hot wire on the plug side is cut off, preventing the cigarette lighter from developing into abnormal overheating, and preventing overheating of various parts on the vehicle side. Damage, burnout, etc. are to be prevented.

The automobile cigarette lighter temperature fuse device according to the present invention having the above-mentioned structure and operation has the following effects.

(a) The wiring configuration of the lead wire connected to the terminal on the power side of the cigarette lighter does not affect the thermal fuse's strength or breakage, and the lead wire does not fall off after the fuse is blown. This is a high-quality automobile cigarette lighter temperature fuse device that is highly reliable and safe, as there are no secondary defects caused by it, and it operates at a predetermined temperature only by the material properties of the case and its shape. can be provided.

(b) Since the structure is simple and the number of components is small, assembly work is easy, and an inexpensive automobile cigarette lighter temperature fuse device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of a conventional automobile cigarette lighter temperature fuse device.
FIG. 2 is a sectional view of a main part of another embodiment of a conventional automobile cigarette lighter temperature fuse device.
FIG. 3 is a cross-sectional view of an automobile cigarette lighter temperature fuse device according to the present invention. FIG. 4 is a sectional view taken along the arrow line AA in FIG. 3. FIG. 5 is a front view of the automobile cigarette lighter temperature fuse device according to the present invention. 6 is a sectional view showing the operating state of the temperature fuse device in FIG. 3; FIG. 12...Socket body, 13...Insulator, 1
4...Bimetal electrode, 15...Shaft, 18...Terminal, 18a...Tapered surface, 19...Case, 19a...Groove, 19c...Protrusion surface, 20...
Connection terminal, 21... elastic contact piece, 21a... contact, 2
2...Insulator, 24...Heat wire cap.

Claims (1)

[Scope of utility model registration request] A connecting terminal screwed onto one terminal and having an elastic contact piece fixed to the tip of the other end is inserted and inserted between a case made of flame-retardant thermoplastic resin and the end face of the terminal and the base of the elastic contact piece. A cigarette lighter for an automobile, comprising: an insulator interposed in the terminal; and the elastic contact piece which is pressed against the tapered surface of the terminal by a protruding surface provided on the inner surface of the case to maintain electrical connection. Temperature fuse device.