JPS609588Y2 - Automotive cigarette lighter temperature fuse device - Google Patents

Description

[Detailed description of the invention] This invention is installed to the power terminal of an automobile cigarette lighter, and prevents phenomena such as thermal deformation, deterioration, or combustion of the attachment part related 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 automobiles that is intended to be avoided.

Conventionally, when using an automobile cigarette lighter, when the knob is pushed in, a hot wire provided in the cigarette lighter is energized, causing the hot wire to become red-hot, and after a certain period of time, the knob pops out.

However, the knob may not be able to pop out due to malfunctions due to foreign matter adhesion, or due to inability to maintain normal usage conditions due to attachment/detachment of commercially available parts that use the socket side of the cigarette lighter as a power socket. The plastic cigarette lighter attachment part could catch fire and cause a fire.

To deal with such problems, there are known devices that cut off the power supply by installing a temperature fuse as shown in Figure 1 or Figure 2, for example, if the cigarette lighter overheats above a predetermined temperature. It had drawbacks in terms of performance, price, etc.

That is, in the configuration shown in FIG. 1, another terminal 4 having a flange 4a is inserted into the other end of the flame-retardant plastic resin case 3 screwed onto the terminal 2 of the power source of the cigarette lighter 1. A spring 5 is wound between the terminal 4a and the inner wall of the case, and the terminal 2 is normally kept electrically energized.When the cigarette lighter 1 overheats to a predetermined temperature or higher, the terminal 2 The threaded part of the case 3 that is exposed to the heat 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, which acts to cut off the power supply from the power source 6. However, this device has the drawback that the time from overheating to shutoff is not specified as a predetermined time.

This is due to the routing state of the lead wire 7 connected to the other terminal 4, that is, when the lead wire 7 is in a free state and the lead wire 7 is in a natural state where its own weight is applied to the other terminal 4. On the other hand, if the lead wire 7 is held in the vicinity of the other terminal 4 by some method, such as a clamper, there will be a difference in the time it takes for the case 3 to detach. It took a long time, and there were cases where it was not shut off 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 ring 9 of the power source of the cigarette lighter 8, and a certain amount of heat is generated by the conduction heat from the cigarette lighter 8. It is composed of a terminal 11 made of a temperature fuse material, such as solder, which melts at a temperature higher than that and cuts off the power supply from the power source 6. In this configuration, the terminal 11 melts due to overheating and separates from the nut member 10. If the terminal 11 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 supply 6. had.

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, the present invention has a breakaway contact part that reliably cuts off the power supply in a predetermined time when the cigarette lighter overheats. It is an object of the present invention to provide a temperature fuse device for an automobile cigarette lighter that does not require installation or detachment of lead wires.

Below, preferred embodiments of the automobile cigarette lighter temperature fuse device according to the present invention are shown in FIGS. 3, 4, and 5.
This will be explained in detail based on FIGS. 6, 7, and 8.

Reference numeral 12 denotes a socket body of a cigarette lighter, and an insulator 1 is connected from an end surface forming the inner bottom of the socket body 12.
The shaft 15 to which the bimetal electrode 14 is fixed is protruded through the insulating washer 16 and the spring washer 1.
A heavy metal electrode 14 is attached and fixed to the socket main body 12 via a terminal 18 which is a nut member.

Reference numeral 19 denotes a case of a temperature fuse device, and the material is a flame-retardant plastic resin that melts at a predetermined superheating temperature, such as polypropylene.

The case is almost cylindrical and has threads on the inside.
One end is screwed into the threaded part on the outer periphery of the terminal 18, and a stopper 19a is integrally formed in the opening of the other end surface to connect between the local parts, and one end perpendicular to the stopper 19a is formed integrally with the opening on the other end surface. A connecting terminal 20 is formed so as to be insertable from the outer circumferential side.

Reference numeral 20 denotes a connection terminal connected to the positive electrode of the power source 6. The connection terminal 20 is made of an elastic spring material, such as phosphor bronze, and the center portion forms an elastic contact piece 20a. The contact 20b on the tip side is connected to the case 19 as shown in FIG.
is inserted into the terminal 18 on the cigarette lighter side.
When the case 19 is screwed and installed, the end face of the terminal 18 is pressed and contacted by the wrapper 19a, and the current from the power source 6 is transferred to the contact 20b1 terminal 18,
The bimetal electrode 14 is energized via the shaft 15.

Further, in the free state, the elastic contact piece 20a is biased in the opening direction with respect to the end face of the terminal 18. That is, when the stopper 19a is removed, the contact point 20b is pushed away from the end face of the terminal 18 as shown in FIG. It has a structure that can be separated.

The stopper 19a in the case 19 is designed to be thermally deformed or fused before the other parts of the case 19 when the cigarette lighter overheats, as shown in FIGS. 3 and 4. It is formed into an elongated bar shape with an extremely small cross-sectional area.

Since the stopper 19a has an extremely small volume compared to other parts of the case 19, it can be said that the amount of heat required to raise the temperature to a predetermined temperature, so-called heat capacity, is extremely small.

Reference numeral 21 denotes an outer case, which fixes the socket main body 12 of the cigarette lighter to the vehicle side mounting portion.

Reference numeral 22 denotes a hot wire cap at the tip on the plug side, and a hot wire (not shown) is mounted inside the hot wire cap.

Next, the action will be explained.

Now, in the cigarette lighter having the configuration shown in FIG.
2 is engaged with the bimetal electrode 14, the current from the positive electrode of the power source 6 flows through the contact 20 of the elastic contact piece 20a of the connection terminal 20.
Terminal 18, shaft 15, and bimetal electrode 1 from b
4 through the hot wire cap on the plug side, the nichrome wire, etc., further flows to the socket body 12, the outer case 21, and the negative electrode of the power supply 6, and the hot wire on the plug side becomes red hot and reaches a predetermined temperature within a predetermined time. , the engagement of the bimetallic electrode 14 is released and the plug-side knob returns to the OFF state, but under such normal operating conditions, there is no abnormal conduction of heat from the hot wire to various parts such as the terminal 18 and the cigarette lighter mounting part. In other words, the temperature does not rise above a predetermined temperature.

However, for some reason, if the engagement between the bimetal electrode 14 and the plug-side hot wire cap 22 is not released even after a predetermined period of time has passed, and the power is continued from the power source 6, the temperature of the terminal 18 will increase due to heat conduction from the hot wire. The case 19 made of flame-retardant plastic resin softens and melts due to heat conduction from the terminal 18 and the elastic contact piece 20. In the process of changing, the stopper 19a portion having a small heat capacity is deformed or fused as shown in FIG.

Thus, the current from the power source 6 is applied to the elastic contact piece 20 of the connecting terminal 20.
The contact 20b of the cigarette lighter is cut off 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 damage or burnout to various parts on the vehicle side due to overheating.

Next, other embodiments shown in FIGS. 6, 7, and 8 will be described.

In another embodiment shown in FIG. 6, the shape of the connecting terminal 23 is 1L.
, and the insertion direction of a lead wire (not shown) from a power source (not shown) that connects to the connection terminal 23 is changed.

In addition, the formation state of the elastic contact piece 23a of the connection terminal 23 is changed, and the shape of the elastic contact piece 23a is adapted to the external shape of the connection terminal 23 and the position of the contact point 23b of the elastic contact piece 23a. Although the insertion part is changed, the basic configuration is the same as that of the embodiment shown in FIG.
The contact point 23b of the terminal 18 is pressed against the end face of the terminal 18 to maintain contact.

Furthermore, when the cigarette lighter overheats to a predetermined abnormal temperature for some reason, the stopper 24a of the case 24 deforms or melts due to the heat, and the contact 23b of the elastic contact piece 23a opens. The same is true for doing the same thing.

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

(b) The cutting performance of the temperature fuse is not affected by the wiring configuration of the lead wire connected to the terminal on the power side of the cigarette lighter, and the secondary damage caused by the lead wire falling off after the cutoff. No problems occur because the structure works at a predetermined temperature simply by reducing the material properties of the case and the heat capacity of the stopper in the case.
It is possible to provide a highly reliable, safe and high-quality automotive cigarette lighter temperature fuse device.

(b) Since the structure is simple and the number of components is small, an inexpensive automotive 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 one-temperature fuse device. FIG. 3 is a sectional view of a cigarette lighter temperature fuse device for an automobile according to the present invention. FIG. 4 is a plan view taken along the arrow line A--A in FIG. 3. FIG. 5 is a side view taken in the direction of the arrow line BB in FIG. 4, and is an explanatory diagram when the temperature fuse device is activated. FIG. 6 is a sectional view of a main part of another embodiment of the automobile cigarette lighter one-temperature fuse device according to the present invention. FIG. 7 is a sectional view of the main part in the direction of the arrow line CC in FIG. 6. FIG. 8 is a plan view taken along arrow line DD in FIG. 6. 12... Socket body, 13... Insulator, 14... Bimetal electrode, 15...
...Axis, 18...Terminal, 19,24...
...Case, 19a, 24a...Stopper 20.23...Connection terminal, 20a, 23a
...Bullet contact piece, 22... Heat wire cap.

Claims (1)

[Scope of utility model registration request] A case made of flame-retardant plastic resin, one end of which is screwed together with one terminal, and a stopper with a smaller heat capacity than other parts is integrally formed on the open tip surface of the other end in a concentric shape, and the case. and a connection terminal having an elastic contact piece inserted into the end face of the terminal and crimped onto the end face of the terminal by the stopper.