Hot bowl for cigarette lighters, in particular of the type mounted on motor vehicles

Abstract: Hot bowl of a cigarette lighter body in particular of the type mounted on motor vehicles, its perimetral surface comprising a bendable lug which pinches one end of the spiral resistance element contained within the lighter by a crimping process.

Description: This invention relates to hot bowls for cigarette lighters, particularly of the type mounted on motor vehicles, and in particular relates to the method of fixing the spiral resistance element into the hot bowl. Various methods of fixing the resistance element are known in the art, one of which uses an elastic ring which compresses the spiral against the inner wall of the hot bowl. Apart from the increased cost due to the elastic ring, this method of fixing involves an operation which is not easy to execute automatically, namely the insertion of the elastic ring into the wall of the hot bowl. The most usual method of fixing the end of the resistance element to the interior of the hot bowl is welding. However this system is subject to certain drawbacks. The first is that the welding can present problems of current passage through the insulating layer of the resistance element. The second problem, and perhaps the more important, is that because of the hardening procedure normally undergone by the wall of the hot bowl the welding cannot be reliably effected, with the result that because of the continuous temperature variations the resistance element becomes detached during the product life. A cigarette lighter according to the preamble of claim 1 is known from US-A-1 803 361. The object of the present invention is to fix the spiral resistance element in the hot bowl of the cigarette lighter body in a way that does not present the aforesaid problems and is of simple and inexpensive implementation. Said object is attained thanks to the characterizing features of claim 1. According to the present invention, a hot bowl for the pusher assembly of a cigarette lighter is disclosed, in particular mounted on motor vehicles and provided with a spiral resistance element connected electrically at two points, wherein the hot bowl comprises a pliable lug on its perimetral surface, characterised in that one end of the spiral resistance element is pinched between said lug and the wall of the hot bowl by a crimping process. Two important functional advantages are obtained by virtue of said characteristic. Firstly, the direct crimping of the last turn of the resistance element overcomes said detachment problems arising from unreliable welding. Secondly, durable and stable fixing is achieved by a very simple operation of very low cost. Further characteristics and advantages of the invention will be apparent from the description given hereinafter by way of non-limiting example with reference to the accompanying drawing, comprising two figures indicated by 1 and 2, and of which: Figure 1 is a partly sectional view of a hot bowl according to the invention; Figure 2 is a plan view of the hot bowl of Figure 1. In the figures the reference numeral 1 indicates overall the body of a cigarette lighter of the type mounted on motor vehicles but not shown in its entirety, with which there is associated a hot bowl 2 formed from sheet metal bent into cup shape. Within the hot bowl 2 there is positioned a spiral resistance element 3 fixed at its inner end 4 to a conductor shaft 5 inserted into the base of the hot bowl 2 via a hole 6 provided in its centre. The conductor shaft 5 forms the first of the two electrical contacts to which the spiral resistance element 3 is connected. The second electrical contact is provided by the connection of the second end 7 of the spiral resistance element 3 to the inner wall of the hot bowl 2. The second connection is made by crimping a lug 8 integral with the lateral wall of the hot bowl 2, by bending said lug over so that it pinches the end of the spiral between itself and the inner wall of the hot bowl. For a better understanding of the advantages of the invention a description will now be given of one of the possible procedures for forming a hot bowl as claimed in claim 1. The procedure consists of a first stage in which a flat sheet metal disc is formed by blanking. Said disc is then punched to obtain a U-shaped aperture close to the outer wall of the disc. Said aperture defines the lug 8 which is later bent over to lock (by a crimping procedure) the outer end 7 of the spiral 3. The external shape of the cup-shaped hot bowl is then obtained by deep-drawing. At this point the spiral is inserted into the hot bowl and crimping is then effected in the aforesaid manner by bending the lug over. The conductor shaft is then inserted into the hole and fixed to the other end of the spiral resistance element 3. It should be noted that the lug 7 can be formed by different methods without leaving the scope of the present invention.

Claims: A hot bowl (2) of a cigarette lighter body (1) in particular of the type mounted on motor vehicles and provided with a spiral resistance element (3) connected electrically at two points (4, 7), wherein the hot bowl (2) comprises a pliable lug (8) on its perimetral surface, characterised in that one end (7) of the spiral resistance element (3) is pinched between said lug (8) and the wall of the hot bowl by a crimping process. A hot bowl as claimed in claim 1, characterised in that that end (7) of the spiral resistance element (3) pinched by the crimping process is the outer end. A hot bowl as claimed in claim 1, characterised in that the lug (8) is formed by a punching process.

Inventors: MARTINA FELICE, MARTINA, FELICE
Applicants: IMOS ITALIA SRL, IMOS ITALIA S.R.L.
Application year: 1993
Main classification: B60N3
IPC codes: B60N3, F23Q7