| Title of Invention | LAMP |
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| Abstract | Lamp having a lamp base, a lamp vessel anchored therein and at least one luminous means, which is surrounded by the lamp vessel, as well as at least two power supply wires, which are passed out of the lamp vessel, are used for supplying voltage to the at least one luminous means and are each connected to an electrical contact element arranged on the lamp base, wherein at least one aperture is provided in the lamp base for the purpose of welding the at least one power supply wire to the corresponding electrical contact element, characterized in that the at least one aperture is designed such that a laser beam having an angle of incidence of zero degrees can be focused onto the surface of the weld point by means of the at least one aperture. FIG 3 |
| Full Text | Lamp The invention relates to a lamp in accordance with the preamble of claim 1. I. Prior art Such a lamp is disclosed, for example, in the patent specification EP 1 006 551 Bl. This document describes a halogen incandescent lamp, in particular a vehicle headlamp, with a metal/plastic base, which is provided with an aperture in order to be able to weld the power supply wires, which protrude out of the lamp vessel, to in each case one metallic contact lug arranged in the base by means of a laser. II. Description of the invention The object of the invention is to provide a lamp of the generic type with an improved welded joint between the power supply line and the electrical contact element. This object is achieved according to the invention by the features of claim 1. Particularly advantageous embodiments of the invention are described in the dependent claims. * • * The lamp according to the invention has a lamp base, a lamp vessel anchored therein and at least one luminous means surrounded by the lamp vessel as well as at least two power supply wires, which protrude out of the lamp vessel, are used for supplying voltage to the at least one luminous means and are each connected to an electrical contact element arranged on the lamp base, at least one aperture being providec. in the lamp base for welding the at least one power supply wire to the corresponding electrical contact element, which is designed in such a way that a laser beam with an angle of incidence of zero degrees can be focused onto the surface of the weld point through the at least one aperture. This means that the at least one aperture is designed in such a way that the laser beam for carrying out the welding operation impinges perpendicularly on the surface of the weld point. As a result, the quality of the welded joint between the power supply wire and the contact lug is improved. In particular, the strength of the welded joint is increased by approximately 30 percent. It has been shown that, in the welding operation illustrated in figure 4 in accordance with the abovecited prior art, '::he laser beam impinges on the surface of the weld point a': an angle of incidence of approximately 22.3 degrees and as a result some of the laser energy is absorbed by the power supply wire and therefore can no longer be used for the welding operation. Given an angle of incidence of the laser beam of zero degrees on the surface of the weld point, as is illustrated schematically in figure 3 for the lamp according to the invention (the angle of incidence is measured against the surface normal of the surface), this disadvantage do.es not occur or only occurs to a lesser extent. Preferably, a correspondingly shaped aperture is provided for each pair of contact lug and power supply wire to be welded ir order to be able to keep the size of the apertures in the base as small as possible. In accordance with the preferred exemplary embodiment, the at least one aperture is arranged az the same height as the weld point. Preferably, the contact elements are in the form of contact lugs, which each have a groove, into which a bent-back end of the corresponding power supply w..re is threaded. This makes it possible to join the parts to be welded together in a simple manner. The weld point is preferably a web which delimits the groove of the contact lug since this can be fused in a simple manner by means of the laser in order to pjroduce the welded joint between the contact lug and the power supply wire. III. Description of the preferred exemplary embodiment The invention will be explained in more detail below with reference to a preferred exemplary embodiment. In the drawing: figure 1 shows a schematic illustration of the preferred exemplary embodiment of the lamp according to the invention with a reflector, in a partially sectioned view, figure 2 shows a cross section through part of the lamp base of the lamp depicted in figure 1, figure 3 shows a plan view of an arrangement for laser-welding the con-act lugs and the bent-back end of the respective power supply line which is arranged in the groove of the contact lugs corresponding to the lamp according to the ' invention, and figure 4 shows a plan view of an arrangement for laser-welding the contact lugs and the bent-back end of the respective power supply line arranged in the groove of the contact lugs corresponding to the lamp in accordance with the prior art. The preferred exemplary embodiment of the invention is a single-filament halogen incandescent lamp, which is provided for use in a motor vehicle headlamp. This lamp has a vitreous, substantially cylindrical lamp bulb 10 with a pinch-seal foot 10a, which is sealed in a gas-tight manner. The dome 10b of the larr.p bulb 10 is provided with a light-absorbent coating. An incandescent filament 11, which is aligned parallel with respect to the lamp bulb axis and is electrically conductively connected to two power supply wires 12, 13, which are passed out of the pinch-seal foot 10a and are made from a molybdenum wire, is used as the light source. The pinch-seal foot 10a of the lamp bulb 10 is fixed in a metallic holder, which comprises the bowl-like holder part 14a, the intermediate ring 14e and the annular support sleeve 14b. In addition to the metallic holder 14a, 14b, the lamp base also has a plastic base part 15, which is provided with the electrical terminals 16, 17 of the larr.p and in which the annular metallic support sleeve 14b is anchored. The support sleeve 14b has three reference tabs 14c lying in one plane and a contact-pressure spring 14d for fitting the lamp in the reflector 20 of a motor vehicle headlamp. Sealing of the reflector 20 takes place by means of a silicone sealing ring 19, which bears aganst the outer wail of the reflector 20 and against the plascic base part 15. The design of the lamp in accordance with the preferred exemplary embodiment and its use in a headlamp is illastrated schematically in figure 1. The electrical terminals 16, 17 of the lamp comprise two metallic contact lugs 16, 17, which are each welded (not depicted in figure 1) to one of the power supply wires 12, 13. The contact lugs 16, 17 are manufactured from sheet steel and are injection-molded in the plastic base part 15 of the lamp base. Said contact lugs 16, 17 each comprise an L-shaped steel sheet. In each case one limb 16a, 17a of the L-shaped contact lugs 16, 17 is in the form of a plug-type contact, while the other limb 16b, 17b is equipped with a groove 16c, 17c, into which in each case the bent-back end 12a, 13a of a power supply wire 12, 13 is threaded. Those regions of the contact lugs 16, 17 which are normally hidden in the cross section in figure 2 are illustrated by dashed lines in figure 2. The angle region of the L-shaped contact lugs 16, 17 is injection-molded tightly in the plastic base part 15 and is therefore not normally visible. The grooves 16c, 17c are each laterally delimited by two webs 16d, 16e and 17d, 17e, respectively, of different lengths. The two webs 16d, 16e and 17d, 17e each have, on their edge facing the grooves 16c, 17c, a bevel 16f, 17f, which bevels are used to thread the power supply wire 12, 13 into the groove 16c, 17c. The shorter web 16e, 17e has a smaller width than the longer web 16d, 17d. The welded joint between the power supply wires 12, 13 and the contact lugs 16, 17 is produced by means of heating the material of the shorter webs 16e, 17e for a short period of time to above their melting point by means of a laser. Once the melt has solidified, the bent-back end 12a, 13a of the power supply wire 12, 13 is connected to the shorter web 16e, 17e. The L limbs 16b, 17b which have been welded to the power supply wires 12, 13 extend as far as into the interior space formed by the support sleeve 14b anchored in the plastic base part 15. The support sleeve 14b is provided with two apertures 18 at the level of the webs 16e, 17e, which apertures are used for the laser welding of the power supply wires 12 and/or 13 to the short webs 16e, 17e of the corresponding contact lug 16 and/or 17 after the lamp base has been fitted. The two apertures 18 in the support sleeve 14b are located next to one another, at the same height as the welded joint between the contact lug 16 and the power supply wire 12 or at the same height as the welded joint between the contact lug 17 and the power supply wire 13. Each of the apertures 18 is designed in such a way that the laser beam 19 can be focused at an angle of incidence of zero degrees onto the surface of the corresponding weld point, i.e. onto the surface of the narrow side of the web 16e or 17e, so as to form the abovementioned welded joints. In other words, the laser beam 19 impinges, as is illustrated schematically in figure 3, perpendicularly on the surface of the narrow side of the web 16e or 17e during the welding process. The invention is not restricted to the exemplary embodiment explained in more detail above. For example, in the case of two luminous means with three power supply wires and three contact lugs, the lamp base can also have three apertures. However, it is also possible for only one single, correspondingly larger aperture to be provided instead of a plurality of apertures in order to perform all of the laser welding operations of the contact lugs and power supply wires through this aperture. We claim: 1. A lamp with a lamp base, a lamp vessel (10) anchored therein and at least one luminous means (11) surrounded by the lamp vessel (10) as well as at least two power supply wires (12, 13), which protrude out of the lamp vessel (10), are used for supplying voltage to the at least one luminous means (11) and are each connected to an electrical contact element (16, 17) arranged on the lamp base, at least one aperture (18) being provided in the lamp base for welding the at least one power supply wire (12, 13) to the corresponding electrical contact element (16, 17), wherein the at least one aperture (18) is designed in such a way that it is possible for a laser beam with an angle of incidence of zero degrees to be focused onto the surface of the weld point through the at least one aperture (18). 2. The lamp as claimed in claim 1, wherein an aperture (18) is provided in the lamp base for each power supply wire (12, 13) . 3. The lamp as claimed in claim 1 or 2, wherein the at least one aperture (18) is arranged at the same height as the at least one weld point. 4. The lamp as claimed in claim 1, 2 of 3, wherein the contact elements are in the form of contact lugs (16, 17), which each have a groove (16c, 17c), into which a bent-back end (12a, 13a) of the corresponding power supply wire (12, 13) is threaded. 5. The lamp as claimed in claim 4, wherein the weld point is arranged on a web (16e, 17e) which delimits the groove (16c, 17c). 6. A lamp with a lamp base substantially as hereinbefore described with reference to the accompanying drawings. |
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| Patent Number | 269210 | ||||||||
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| Indian Patent Application Number | 6737/DELNP/2008 | ||||||||
| PG Journal Number | 42/2015 | ||||||||
| Publication Date | 16-Oct-2015 | ||||||||
| Grant Date | 09-Oct-2015 | ||||||||
| Date of Filing | 04-Aug-2008 | ||||||||
| Name of Patentee | OSRAM GmbH , a German Company | ||||||||
| Applicant Address | HELLABRUNNER STR.1, 81543 MUNCHEN, GERMANY | ||||||||
Inventors:
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| PCT International Classification Number | H01J 5/62 | ||||||||
| PCT International Application Number | PCT/EP2007/051558 | ||||||||
| PCT International Filing date | 2007-02-19 | ||||||||
PCT Conventions:
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