Incandescent lamp and locating body therefor

Abstract: In an incandescent lamp, comprising a translucent envelope (2) having flattened end (3) of rectangular cross-section, a base element (5) surrounding the flattened end part (3) and having rectangular cross-section, two current lad-ins (7a, 7b) connected with an incandescent body (4) arranged within the envelope (2) and with the base element (5) and thereby with a connecting cable (8), a centering plate (6) with a rectangular opening for receiving the base element (5), wherein the centering plate (6) is made with at least one flange element (10) arranged on the side of the centering plate (6) facing away from the envelope (2), the base element (5) being made of thinner plate than the centering plate (6), a locating body (9) stepwisely shaped for receiving the flange element (10) is applied, the locating body (9) made of thinner wall than the centering plate (6) is fixed on the base element (5), has an edge (14) separated from the base element (5) by a gap, wherein the edge (14) of the locating body (9) covers at least partly the at least one flange element (10) of the centering plate (6), the flange element (10) of the centering plate (6) is between the base element (5) and the locating body (9), further the flange element (10) of the centering plate (6) and the locating body (9) are connected by a thermal method of joining.

Description: FIELD OF THE INVENTION The present invention concerns an incandescent lamp, especially for use in the headlight systems of motor cars, comprising a translucent envelope having a flattened end part of substantially rectangular cross-section, a base element surrounding the flattened end part and having a substantially rectangular cross-section, two current lead-ins respectively connected with an incandescent element or body arranged within the envelope, and with the base element and thereby with a connecting cable, and a centering plate with a rectangular opening for receiving the base element from one side facing the envelope, wherein the centering plate is made with at least one flange element arranged on the reverse side of the centering plate. The base element may be thinner than the centering plate. The incandescent lamp as proposed is capable of facilitating the process of optical adjustment of the incandescent body. BACKGROUND OF THE INVENTION The electric incandescent lamps applied in headlights of vehicles and in projector systems have to be arranged with high accuracy in an optical system determined by a basic plane. For carrying out this operation the incandescent lamp is equipped with a base element and fixed thereby in an optical adjusting arrangement. The base element is then slid in the arrangement in order to achieve the required position of the incandescent body which should lie in the focus plane of the body of the headlight or projector system. This is generally done by applying a centering plate in the form of a disc which is joined with the base element after completing the optical adjustment operation. The connection is generally achieved by brazing or welding. The disadvantage of the brazing process is that it takes a long time and therefore care should be taken to prevent high thermal load on the incandescent lamp. The general path of development has been to exclude brazing and to apply a welding process which results in shortening the time of operation for joining the base element and the centering plate. In the known incandescent lamp arrangements the centering plate is relatively thick, the base element is thinner than the centering plate which is equipped with a flange element connecting the centering plate and the base element. The flange projects from the surface of the centering plate at the base element. If the centering plate and the base element are joined by spot welding, the flange element of the thick centering plate is pressed to the thin base element which can suffer deformation under the influence of this pressure. DE-A-26 05 433 discloses an electric incandescent lamp having a base element made with hooked flange elements on its opposite longitudinal sides. The flange elements are arranged with ends lying in a gap between the centering plate and the base element and in this position it is possible to join the centering plate by its flange element with the base element. This construction is advantageous for welding but linked with difficult problems when the optical adjusting operation is to be carried out. The hooked flange elements protrude from the surface of the base element and they end behind the edge of the opening of the centering plate. In this way relatively big connecting surfaces are assured and this fact limits the possibility of precise translation necessary when the incandescent body of the lamp is to be adjusted. OBJECT OF THE INVENTION The present invention is intended for creating an incandescent light source wherein the centering plate required for optical adjustment can be joined with the base element of the lamp by a simple welding operation, the incandescent light source may be translated within a wide range when adjusting is necessary and the position assured by adjusting can be fixed by a simple, quickly realized welding step resulting in a fixed position of high strength. The invention is based on the recognition that the centering plate and the base element of the incandescent body should be linked with a locating body of stepwise construction ensuring a reliable guidance rendering possible all translations necessary during the optical adjusting process and facilitating the welding step required for joining the centering plate and the base element. Hence, one aspect of the invention proposes an incandescent lamp, comprising a translucent envelope having a flattened end part of substantially rectangular cross-section, a base element surrounding the flattened end part and having a substantially rectangular cross-section, two current lead-ins one end of each of which is connected with an incandescent element arranged within the envelope while the other end of each is connected with the base element or with a connecting cable and a centering plate having a rectangular opening for receiving the base element from one of its sides facing the envelope, while its opposite side is formed with at least one flange element characterised in that a stepwise shaped locating body is provided for receiving the or each flange element; in that the locating body is fixed on the base element and has an edge separated from the base element by a gap, wherein the edge of the locating body at least partly overlaps with the or each said flange element which latter lies between the base element and the locating body; and in that the or each said flange element and the locating body are connected with one another by a thermal bond. In an especially advantageous embodiment of the incandescent lamp realised according to the present invention nipples having a hemicylindrical or hemispherical shape are present in the gap for ensuring guidance of the flange elements and the centering plate when carrying out optical adjusting of the incandescent body. Preferably, the nipples are prepared at the edge(s) of the locating body and they are manufactured as protrusions from the inner surface of the locating body. The height of the nipples may at most be 1 mm. The locating body of the incandescent lamp of the invention is especially advantageous because it is capable of ensuring auxiliary fixation and/or strengthening of the connecting cable. Preferably, the locating body is of generally U-shaped cross-section for receiving both the base of the incandescent lamp and the flange protruding from the centering plate, and comprises two stepwise narrowing walls facing one another and forming a preferably integral unit with upper and lower parts limited from two sides by substantially parallel straight planar plates, the lower part having walls connected one with another. The positive effect of the invention follows basically from this locating body, in that it makes it possible to move or translate the incandescent lamp and thereby the incandescent element (the filament of the lamp) in a required range and it assures the further advantage that the connecting cable can be fixed and/or strengthened with higher reliability than in the known constructions by applying a bent section in a plate connecting the walls of the lower part. The thin surface parts of the locating body cover the flange elements of the centering plate from outside and this creates the conditions of facilitating the welding process: the required securing can be made by simple spot weldings. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described by way of example only by presenting a preferred embodiment with reference to the accompanying drawings, wherein:- Fig. 1 shows a schematic side view, partly in cross-section of an incandescent lamp formed according to the invention, Fig. 2 represents a front view of the incandescent lamp shown in Fig. 1, and Fig. 3 is a view of a stepwise realised locating body with spherical nipples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT There is shown a preferred embodiment of an incandescent lamp 1 shown in Figs. 1 and 2 which is a headlight lamp applied especially in motor vehicles (cars). Hence, an incandescent lamp 1 is proposed which is equipped with a translucent envelope 2 made generally of glass. In the inner space of the envelope 2 an incandescent body 4 (filament) manufactured according to the general practice of the lighting industry is arranged. The envelope 2 carries at one end a flattened end part 3 of substantially rectangular cross-section. The flattened end part 3 is surrounded by a base element 5 which also has a substantially rectangular cross-section. The base element 5 is connected with a centering plate 6 generally of disc form and the centering plate 6 is contacted with a locating body 9. The incandescent lamp 1 is equipped with current lead-ins 7a and 7b coupled with a connecting cable 8. A supporting member 15 is arranged at the locating body 9 for protecting the connecting cable 8 from mechanical stresses. The base element 5 may have ears 13 (Fig. 1). The locating body 9 (Fig. 3) forms a stepwise constructed bracket made with upper and lower parts, the upper part having substantially parallel walls defining a width greater than the substantially parallel walls of the lower part. The locating body 9 is manufactured from a relatively thin metal sheet when compared to the centering plate 6 and has an inner surface 22 bearing nipple(s) 24, here two, which are generally cylindrical or hemispherical dimples protruding from the inner surface 22. In the generally U-shaped lower part, which may have openings to receive the ears 13 (not shown in Fig. 3) the side walls are connected by a bottom part having a circularly curved middle section 20. The locating body 9 is of suitable metal sheet. The flattened end part 3, as shown in Figs. 1 and 2, is connected with the base element 5. The base element 5 is manufactured from a plate of about 0.2 mm thickness and has two wider and two narrower sides. On the wider sides there may be ear(s) 12, e.g. two ears for each side, which are arranged in parallel with the longitudinal axis of the base element 5 and are flanged out from the surface thereof. The ears 12 serve for fixing the base element 5 on the flattened end part 3. The centering plate 6 is made from a metal sheet of 0.8 mm thickness and is prepared with an inner opening of rectangular shape (not illustrated in the drawing) for receiving the base element 5 from a first side. The opening is at least partly limited laterally by slightly curved flange elements 10 protruding from the reverse side of the centering plate 6. The base element 5 is arranged in this rectangular opening of the centering plate 6 and is contacted with the flange elements 10. The base element 5 is made with a closing member 11 reaching the inner space defined by the flange elements 10. The closing member 11 is arranged within the bracket-type locating body 9 and lies in a gap between the base element 5 and the locating body 9. In this way the flange elements 10 and an edge 14 of the locating body 9 match one another. The flange elements 10 are curved out from the surface of the centering plate 6. The matched connection does not mean a fixed coupling between the base element 5 and the centering plate 6. The current lead-in 7a is connected with the base element 5 and the current lead-in 7b with the connecting cable 8. The incandescent lamp of the invention may be applied as follows: The incandescent lamp 1 as shown in Figs. 1 and 2 is arranged together with the centering plate 6 matching the base element 5 in an optical adjustment apparatus (not shown in the drawing). The positions of the centering plate 6 and the incandecent element 4 are modified as necessary for setting the required optical conditions lighting. The nipples 24 on the inner surface 22 of the locating body 9 facilitate the translation (sliding) of the centering plate 6 because it is a surface contact between the nipples 24 and flange elements 10 of the centering plate 6. In this way a relatively long range translation is possible without breaking the connection between the elements to be adjusted. The locating body is mechanically linked with the base element 5 by the means of the ears 13 wherein the flange elements 10 of the centering plate 6 and the edge 14 of the locating body 9 can be joined by applying a spot welding process. The locating body 9 consists of a metallic plate, e.g. of thickness 0.5 mm. As shown in Fig. 3, it consists of upper and lower parts with a stepwise changing distance between the opposite walls. The curved middle section 20 connecting the opposite sides of the lower part is very advantageous for fixing the connecting cable 8. The supporting member 15 flanging from the surface of the base element 5 increases the stability, reliability of fixing the connecting cable 8. The nipples 24 constitute generally hemispherically shaped knobs (small protrusions) on the inner surface 22 of the locating body 9. Their height makes out generally less than 1 mm, it lies preferably in the range about 0.15 mm, i.e. the nipples 24 form small surface elements of the locating body 9. In this way it is possible to ensure that the envelope 2 together with the incandescent element 4 is slidably guided in the inner space of the locating body 9 until the required optical conditions are achieved. The locating body 9 is very advantageous in the mass production of the electric incandescent lamps to be applied in headlights of motor vehicles. If necessary, the nipples 24 may not be omitted and the flange elements 10 replaced by appropriate surface elements. The incandescent lamp 1 of one aspect of the invention may be realized in different ways and an important feature is that the base element 5 is connectable with the stepwise constructed locating body 9, e.g. in the form shown in Fig. 3. The arrangement renders it possible for the incandescent lamp to slide in the required manner and range and simultaneously to protect the connecting cable against mechanical stresses. An important advantage is that the spot welding process will in practice not harm the base element of the incandescent lamp. However, whilst the invention is shown here with reference to a specific embodiment to be applied in the motor industry for preparing headlights, it is generally intended to be restricted only according to the scope of protection of the claims.

Claims: Incandescent lamp, comprising a translucent envelope (2) having a flattened end part (3) of substantially rectangular cross-section, a base element (5) surrounding the flattened end part (3) and having a substantially rectangular cross-section, two current lead-ins (7a, 7b) one end of each of which is connected with an incandescent element (4) arranged within the envelope (2) while the other end of each is connected with the base element (5) or with a connecting cable (8), and a centering plate (6) having a rectangular opening for receiving the base element (5) from one of its sides facing the envelope (2), while its opposite side is formed with at least one flange element (10), characterised in that a stepwise shaped locating body (9) is provided for receiving the or each flange element (10); in that the locating body (9) is fixed on the base element (5) and has an edge (14) separated from the base element (5) by a gap, wherein the edge (14) of the locating body (9) at least partly overlaps with the or each said flange element (10) which latter lies between the base element (5) and the locating body (9); and in that the or each said flange element (10) and the locating body (9) are connected with one another by a thermal bond. An incandescent lamp according to claim 1, characterised in that the locating body (9) and the or each flange element (10) of the centering plate (6) are welded together. An incandescent lamp according to claim 1 or 2, characterised in that nipple(s) (24) of hemicylindrical or hemispherical shape is or are formed on the locating body (9) on the flange element(s) (10) for ensuring contact between and guidance of the flange element(s) (10) and the centering plate (6) when carrying out optical adjustment of the incandescent element (4). An incandescent lamp according to claim 3, characterised in that the said nipple(s) (24) protrude(s) into the gap from the edge(s) (14) of the inner surface (22) of the locating body (9). An incandescent lamp according to claim 3 or 4, characterised in that the height of the nipple(s) (24) is at most 1 mm. An incandescent lamp according to any preceding claim, characterised in that the locating body (9) is applied for auxiliary fixation and/or strengthening of the connecting cable (8). An incandescent lamp according to any preceding claim, characterised in that the material of the base element (5) is thinner than that of the centering plate (6). An incandescent lamp according to any preceding claim, characterised in that the locating body (9) has a thinner wall than that of the centering plate (6). A locating body (9) for use with an incandescent lamp according to claim 3, characterised in that said body (9) is of generally U-shaped cross-section having a base and spaced-apart upstanding side walls each of which is stepped, the base including an arcuately offset portion (20) forming an internal channel or groove, and further characterised in that each side wall is provided with internal, inwardly projecting nipple(s) (24) adjacent the free end of said side wall. A locating body according to claim 9, characterised in that each side wall is formed, e.g. by striking-out to receive outwardly projecting ear(s) (13) on the base element (5).

Inventors: BUSAI GYULA, HORVATH GYOERGYI, LOSONCZI ZOLTAN, OCSOVAI AKOS, POZSONYI ISTVAN, SZABO GYOERGY, VAJO GYOERGY, BUSAI, GYULA, HORVATH, GYOERGYI, LOSONCZI, ZOLTAN, OCSOVAI, AKOS, POZSONYI, ISTVAN, SZABO, GYOERGY, VAJO, GYOERGY, Horvath, Györgyi, Szabo, György, Vajo, György
Applicants: TUNGSRAM RESZVENYTARSASAG
Application year: 1990
Main classification: H01K1
IPC codes: H01K1, H01L21