DE2436434B2 - OVERHEATING PROTECTION FOR ELECTRIC CIGAR LIGHTER - Google Patents

Description

The invention relates to an overheating protection for a socket with bimetal springs and a Plug with heating element having electric cigar lighter, in particular for motor vehicles, the in the event of overheating of the heating element of the lighter by means of a bimetal element, a short circuit to Interruption of the heating circuit triggers

The use of plastic dashboards in motor vehicles provides protection from overheating the cigar lighter is particularly important. In the event of overheating, the plastic dashboard or the plastic console, which causes the cigar lighter to fall on bypassed power lines and through this May cause fire damage. Such overheating of the cigar lighter occurs when, for. B. the axially displaceable part of the igniter plug jammed or caught for some reason, and As a result, the heating element cannot be released independently by the bimetal springs, but the The circuit is switched on and off by opening and closing the bimetal springs. As long as this process works properly, the lighter will not overheat. There is however, cases in which spark erosion due to frequent opening and closing of the bimetal springs occurs and the contact resistance increases and finally the welding of a bimetal spring with the glow elements cup takes place. After welding, a continuous current flows, which leads to overheating.

Overheating protection arrangements are already known in which the formation of the tiimetallfedem for the glow element or an additional one U-shaped bracket over the socket housing causes a short circuit to the circuit to trigger lying fuse and thus to interrupt the power supply and a Avoid overheating the cigar lighter (DT-PS 19 50 768). The free bimetal spring or the U-shaped bracket gets so far with this overheating deflected until he touches the housing a Short circuit triggers

The known overheating protection arrangements have the disadvantage of thermal inertia so that the The heating element is switched off at such a late point in time that the plug and socket can be damaged. The replacement of the socket is then required, which is often very expensive.

The object of the invention is therefore to create an overheating protection that is already after a very short Overheating duration triggers the short circuit. This is achieved according to the invention in that the The bimetallic element is designed as a prestressed disk and is arranged in the area of the heating element When overheated, the disc jumps over due to its bias and touches the heating element, so that through Bridging the heating element triggers a short circuit, and springs after the cooling down Heating element back to its original position.

The overheating protection according to the invention has the advantage that it is simple in construction and therefore a Economical mass production allowed. The cigar lighter is not damaged when the overheating protection is activated Individual parts, in particular a replacement of the socket, is not required by the arrangement according to According to the invention, there is no increase in the cost of assembly because the short-circuit element described is used instead of a cover plate. All parts of the Cigar lighter can be used without any modification. For mass production, this is of great importance.

In an advantageous development of the invention, it is recommended that the disc with an embossing or a To provide the web with angles. Disc and heating element can form one component. Furthermore can the disc be supported by a sleeve attached to the web.

Exemplary embodiments of the invention can be taken from the drawing and the description.

Show it

Fig. 1 is a partial section through a cigar lighter with the overheating protection according to the invention in Rest position,

F i g. 2 the cigar lighter according to FIG. 1 in switch-on position,

F i g. 3 the cigar lighter according to FIG. 2 when the overheating protection is triggered,

F i g. 4 a plan view and a section through the bimetal disc of the overheating protection,

Fig.5 and Fig.6 further embodiments of the Bimetal element for overheating protection.

The cigar lighter according to FIG. 1 consists of socket 1 and plug 2 with plug sleeve 3, Handle 4, ejection spring 5, shaft 6 and glow element 7. In the socket 1 are the bimetallic springs iS and 11, which are connected to the car battery via the bolt 12 and the connection contact 14. The connection contact 15 is connected to the socket 1 and depends on mass. The glow element 7 is screwed into the shaft 6 with a threaded pin 8. Above the cup of the glow element 7 is the one shown in FIG. 4 shown bimetallic disc 20, which forms the overheating protection The sleeve 21 fastened to the shaft 6 against an insulating disk 22 resting on the cup of the glow element 7 pressed The disc 20 is pretensioned by an embossing so that it can be used during normal use.

temperature remains in the position shown

When the plug 2 is pressed in, the glow element 7 gets between the bimetal springs 10 and 11, like this F i g. 2 shows this switched-on position is maintained until the glow element 7 is heated up is Due to the resulting heat, the bimetal springs 10 and 11 bend to the side and give the connector 2 free, which is pressed by the ejection spring 5 into the removal position.

If heat is supplied over a longer period of time, as is the case with overheating, a higher temperature arises Temperature than the operating temperature. The disc 20 is expanded by the bimetal effect, and the Edge of the Bimeiallelementes springs over the pressure point in the opposite position, whereby an electrical upper bridging of the heating resistor in the cup of the glow element 7 takes place Short circuit triggered The fuse on the iro heating circuit responds and the power supply is open interrupted. After cooling, the disk 20 springs back to its original position, and the The plug can be used again. Since the short circuit is triggered early, the socket 1 is with the Bimetal springs 10 and 11 not damaged and replacement not necessary. Even with mechanical ones Defqrmierungen the bimetal springs 10 and 11 addresses the overheating protection in the manner described and thus protects against overheating of the cigar lighter.

Instead of the round bimetal disc 20 according to FIG. 4 can also a disc 24 with bends 25 and 26 (FIG. 5) or one with bends 28 and 29 provided web 30 (Fig. 6) can be used.

For this purpose 2 sheets of drawings

Claims (5)

Patent claims: 1. Overheating protection for an electrical cigar lighter with a socket with bimetal springs and a plug with a heating element, in particular for motor vehicles, which, when the glow element of the lighter overheats, by means of a Bimetal element triggers a short circuit to interrupt the heating circuit, thereby characterized in that the bimetal element is designed as a prestressed disc (20) and in the Area of the heating element (7) is arranged 2. Overheating protection according to claim 1, characterized in that the disc (20) has an embossing> 5 having 3. Overheating protection according to claim 1, characterized in that the disc (24) has a web (30) with angulations (25,26,28,29) 4. Overheating protection according to one of claims 1 to 3, characterized in that the disc (20) forms a component with the glow element (7) 5. Overheating protection according to one of claims 1 to 4, characterized in that the disc (20) is supported by a sleeve (21) attached to the plug (2).