Title of Invention

"ELECTRIC LAMP"

Abstract

The invention to an electric lamp, in particular a motor vehicle lamp, with a base which has a connection region (14), consisting of an electrically insulating material and provided with the electrical connections (15). The electrical leads (11) led out from the lamp bulb (10) are welded in the internal space (18) of the connection region (14) to the electrical connections which are designed as contact lugs (15) . In order to seal it in gastight fashion, according to the invention the base has one or more shaped parts (19) which consist of a thermally stable, elastic and compressible material and bear force-fittedly on the wall bounding the internal space (18) and on the electrical lead (11) led through the shaped part or parts (19). The force-fit is produced by means of the contact lugs (15) which exert pressure on the shaped part or parts (19). Figure 2

Full Text

Electric lamp The invention relates to an electric lamp according to the precharacterizing clause of Patent Claim 1. An electric lamp of this type, corresponding to the precharacterizing clause of Patent Claim 1, is, for example, disclosed in Patent Specification EP 0,172,529. This document describes an electric incandescent lamp, in particular a motor vehicle headlight lamp, with a lamp bulb pinched on one side and with a lamp base consisting of metal and plastic parts. The pinch base of the lamp bulb is fixed in a metal retention part of the lamp base, while the electrical connections of the lamp, which are designed as contact lugs, are fitted in the lower part of the base, which consists of plastic. The lower part of the base has a cavity into which the electrical leads of the lamp, which are led out from the pinch base, project. These electrical leads are each welded to one end of a contact lug in the cavity of the lower part of the base. In order to seal the base, the cavity is filled with a casting compound. This seal ensures that no moisture, which would cause the reflector to corrode, can penetrate through the lamp base into the headlight. One object of the invention is to provide an electric lamp, having a gastight base, which has an improved design and, in particular, does not require the use of a cement or casting compound to make the seal. This object is achieved according to the invention by the characterizing features of Patent Claim 1. Particularly advantageous embodiments of the invention are described in the subclaims. The electric lamps according to the invention have a lamp base which has a connection region, consisting of an electrically insulating material, in which the electrical connections of the lamp are fitted. The connection region has a cavity into which one or more electrical lead [sic], led out from the lamp bulb, project. They are each connected there in an electrically conducting manner to the end of an electrical connection, which is designed as a contact lug. According to the invention, the lamp base is sealed with the aid of one or more shaped parts, provided with lead-throughs for the elec-trical leads, which consists or consist of a thermally stable, elastic and compressible material. The shaped part or parts are seated on at least one contact lug and bear force-fittedly on the wall bounding the cavity and on the electrical lead or leads led through. In this case, the force-fit is advantageously produced by means of the at least one contact lug, which exerts pressure on the shaped part or parts. Furthermore, the shaped parts or part are advantageously arranged in a matched recess. The pressure exerted by the at least one contact lug onto the shaped part or parts is thereby distributed uniformly over the entire body of the shaped part or parts, and an optimum force-fit of the shaped part or parts on the adjoining cavity walls and on the electrical lead or leads led through, is achieved. In the preferred illus-trative embodiment, the shaped part or parts advanta-geously consists of silicone. The use of a plurality of comparatively thick-walled-tubular shaped parts made of silicone, which each have a lead through for one of the electrical leads projecting into the cavity of the connection region, has proved advantageous. The contact lug ends projecting into the cavity are advantageously designed in the form of claws and are hooked or gripped on the cavity wall. Secure preliminary fixing of the mechanically stressed contact lugs can thereby be ensured even before the contact lugs have been welded to the electrical leads. In order to facilitate the welding of the electrical lead and the corresponding contact lug, the contact lugs are advantageously each equipped with a hole for the electrical lead. The lead-throughs for the contact lug or the contact lugs in the connection region of the base are advantageously each equipped with an insertion bevels [sic], which allow insertion of the contact lugs obliquely with respect to the base axis and subsequent tilting of the contact lugs into alignment with the base axis. The cavity of the connection region is sealed with the aid of a cover, which advantageously has a web which extends into the cavity and is seated on that surface of the contact lug or the contact lugs which faces away from the shaped part or the shaped parts. This web gives additional retention for the contact lugs. The connec-tion region of the base advantageously consists of a thermally stable plastic. Accordingly there is provided an electric lamp with a lamp bulb having lead wires leading out from the lamp bulb, the bulb being supported by a base which incorporates a connection region made of electrically insulating material and provided with electrical connections, wherein the connection region manifests a cavity into which at least one lead wire of the electric lamp projects, and at least one electric connection of the base is formed by a contact lug which projects into the cavity in an electrically conducting manner with a lead wire of the lamp, further characterized in that at least one part consisting of a heat-resistant, elastic material is located in the cavity of the connection region. the shaped part has at least one passage for a lead wire of the electric lamp. the shaped part sits on at least one contact lug and abuts in a press fit the wall delimiting the cavity and the at least one lead wire passed there though. The invention will be explained in more detail below with reference to a preferred illustrative embodiment. Figure 1 shows a cross-section through the electric lamp according to the preferred illustrative embodi-ment, in schematic representation Figure 2 shows a cross-section through the connection region of the base of the lamp according to the preferred illustrative embodiment in Figure 1 In the preferred illustrative embodiment of the electric lamp according to the invention, the lamp is a single-filament incandescent halogen lamp, which is intended for use in a motor vehicle headlight. This lamp has an essentially cylindrical glass lamp bulb 10 with a pinch-sealed lamp bulb end l0a, which is usually denoted as the pinch base lOa. The dome l0b of the lamp bulb 10 is provided with a light-absorbing black coat. The light source used is an incandescent filament lOc which is aligned parallel with the axis of the lamp bulb and is connected in an electrically conducting manner to the electrical leads 11 led out from the pinch base lOa. The lamp bulb 10 is fixed with its pinch base lOa in a metal retention part 12 which is designed as a fastening ring. The fastening ring 12 is supported by an annular metal support bush 13. The support bush 13 has four integrally formed welding lugs 13a which are spot-welded or laser-welded to the fastening ring 12. In addition to the metal fastening ring 12 and the metal support bush 13, the lamp base also has a plastic base part 14 which is provided with the electrical connections 15 of the lamp and in which the support bush 13 is anchored. This plastic base part 14 forms the connection region of the lamp base. The electrical connections 15 of the lamp are designed as contact lugs which are each welded to one of the electrical leads 11. The plastic base part 14 is an injection-moulded part into which the metal support bush 13 is injected. The plastic base part 14 has three integrally formed reference protrusions 14a, which are arranged eguidistantly around a circumference and are used for aligning the incandescent filament lOc and for fastening the lamp in the reflector 17 of the headlight. The reference protrusions 14a, which engage in the opening 17a of the reflector 17, which opening is designed as a lamp holder, are each covered by a cover tongue 13b, which is formed integrally on and angled away from the support bush 13, and are thus shielded from the infrared radiation produced by the incandescent filament lOc. The plastic base part 14 furthermore has an annularly extending, conically designed groove 14b in which a rubber or silicone sealing ring 16 is arranged. The sealing ring 16 bears on the outside of the reflector wall 17 and seals the reflector opening 17a which is designed as a lamp holder. The internal diameter of the sealing ring 16 is matched accurately to the conically designed groove 14b and varies linearly with the height of the sealing ring. The three reference protrusions 14a, the sealing ring 16 and a pressure spring 13c, formed integrally below a reference protrusion 14a on the metal support bush 13, are used for precise fastening of the lamp in the lamp holder 17a of the reflector. The lamp base and the lamp holder 17a form a bayonet joint. The details of the plastic base part 14 which forms the connection region are represented in Figure 2. For the sake of clarity, the pinch base lOa is not shown in Figure 2, and the electrical leads 11 are shown only partly, that is to say not in full length. The plastic base part 14 has a cavity 18 into which the two electrical leads 11, which are led out from the pinch base lOa of the lamp bulb 10, and the ends of two contact lugs 15 project. In the cavity 18 there are two tubular shaped parts 19 made of silicone, which are each arranged in a matched recess 18a formed by the walls of the plastic base part 14. The external diameter of the tubular shaped parts 19 is considerably greater than its internal diameter. Each of the electrical leads 11 is led through the lead-through of a tubular shaped part 19 and through a hole 15b of the end, projecting into the cavity 18, of the contact lug 15 which is welded to this lead. The shaped parts 19 are each seated on a contact lug 15. In this case, each contact lug 15 exerts pres-sure on the corresponding shaped part 19, so that the latter is slightly compressed in the axial direction of the tube, and therefore bears with force-fit on the walls defining the recess 18a and on the electrical lead 11 led through. In this way, gastight sealing of the lamp base is ensured in the region of the electrical leads 11. Those ends 15a of the contact lugs 15 which project into the cavity 18 are designed in the form of claws and are gripped in the back wall of the plastic base part 14. The lead-throughs 20 in the plastic base part 14, which are intended for the contact lugs 15, each have an insertion bevel 20a which facilitates mounting of the contact lugs 15. The cavity 18 is sealed with the aid of a snap-on cover 21. The inside of the cover 21 is provided with an integrally formed web 22, which extends into the cavity 18, is seated on that surface of the contact lugs 15 which faces away from the shaped parts 19 and affords additional retention for the mechanically stressed contact lugs 15. When fitting the lamp into the base, after the fastening ring 12, which supports the pinch base lOa, has been fastened to the retention element 13, the tubular shaped parts 19 are threaded onto the respective electrical lead 11 and are fitted into the respective matched recess 18a. After this, the contact lugs 15 are led, starting from the cavity 18, along the insertion bevels 20a which extend obliquely with respect to the base axis A-A, and through the lead-throughs 20 in the plastic base part 14. The contact lugs 15 are then tilted into alignment with the base axis A-A, so that the electrical leads 11 are threaded through the hole 15b in the corresponding contact lug 15. The tubular shaped parts 19 are in this case pressed through the contact lugs 15 into the recesses 18a and slightly compressed, so that the shaped parts 19 bear force-fittedly on the walls bounding the recesses 18a and on the electrical leads 11 led through the shaped parts 19. At the same time, when the contact lugs 15 are tilted into alignment with the axis A-A of the base, the claw-like ends 15a of the contact lugs 15 grip in the back wall of the plastic base part 14. This provides preliminary fixing of the contact lugs 15 in their axial orientation. Those ends of the electrical leads 11 which protrude through the holes 15b are then welded to the contact lugs 15. After this, the cavity 18 is sealed with the aid of the snap-on cover 21. The invention is not restricted to the illustrative embodiment explained in detail above. By way of example, instead of a plurality of tubular shaped parts, it is also possible to use a single shaped part which consists of a thermally stable, elastic and compressible material and is provided with a plurality of lead-throughs, each for one of the electrical leads fed out from the lamp bulb. Furthermore, those ends of the contact lugs which project into the cavity of the plastic base part may, for example,, be latched behind a projection on the cavity wall. Thus, they need not necessarily have a claw-like design. The thermosets and thermoplastics conventionally used in lamp technology are suitable as a material for the plastic base part 14. Claim: 1. An electric lamp with a lamp bulb having lead wires leading out from the lamp bulb (10), the bulb being supported by a base which incorporates a connection region (14) made of electrically insulating material and provided with electrical connections (15), wherein the connection region (14) manifests a cavity (18) into which at least one lead wire (11) of the electric lamp projects, and at least one electric connection (15) of the base is formed by a contact lug which projects into the cavity in an electrically conducting manner with a lead wire (11) of the lamp, further characterized in that at least one part (19) consisting of a heat-resistant, elastic material is located in the cavity (18) of the connection region (14). • the shaped part (19) has at least one passage for a lead wire (11) of the electric lamp. the shaped part (19) sits on at least one contact lug (15) and abuts in a press fit the wall delimiting the cavity (18) and the at least one lead wire (11) passed therethough. 2. The electric lamp as claimed in claim 1, wherein the shaped part comprises of a heat resistant, elastic and slightly compressible material. 3. The electric lamp as claimed in claim 1, wherein the shaped part (19) is positioned in an exactly matching recess (18a). 4. The electric lamp as claimed in claim 1, wherein the shaped part (19) consists of silicon. 5. The electric lamp as claimed in claim 3, wherein a tube-like shaped part (19) is available for each lead wire (11) projecting into the cavity. 6. The electric lamp as claimed in claim 1, wherein a press-fit is produced in that the at least one contact lug (15) exerts pressure on the shaped part (19). 7. The electric lamp as claimed in claim 1, wherein the end (15a ) of the at least one contact lug (15) that projects into the cavity (18) is hooked on a wall of the base. 8. The electric lamp as claimed in claim 7, wherein the end (15a) of the at least one contact lug (15) that projects into the cavity (18) is shaped like a claw. 9. The electric lamp as claimed in claim 1, wherein the at least one contact lug (15) has an opening (15b) for the lead wire (11) connected to the at least one contact lug (15). 10. The electric lamp as claimed in claim 1, wherein the connection region (14) of the base consists of plastic. 11. The electric lamp as claimed in claim 1, wherein the connection region (14) has a passage (20) for the at least one contact lug (15), the said passage having an insert bevel (20a) which permits the introduction of the contact lugs (15) at an angle to the base axis A-A and then the tipping of the contact lugs (15) in the base axis (A-A). 12. The electric lamp as claimed in claim 1, wherein the base has a cover (21) which closes off the cavity (18) in the connection region (14). 13. The electric lamp as claimed in claim 12, wherein the cover (21) has a web extending into the cavity (18) and said web sits on a surface of the at least one contact lug (15) that faces away from the shaped part (19). 14. Electric lamp with a lamp bulb substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

387-del-1997-abstract.pdf

387-del-1997-claims.pdf

387-del-1997-correspondence-others.pdf

387-del-1997-correspondence-po.pdf

387-del-1997-description (complete).pdf

387-del-1997-drawings.pdf

387-del-1997-form-1.pdf

387-del-1997-form-13.pdf

387-del-1997-form-19.pdf

387-del-1997-form-2.pdf

387-del-1997-form-3.pdf

387-del-1997-form-4.pdf

387-del-1997-form-6.pdf

387-del-1997-gpa.pdf

387-del-1997-petition-138.pdf

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