Title of Invention

"SHADING DEVICE FOR A MOTOR VEHICLE HEADLAMP"

Abstract

Shading device for a motor vehicle headlamp, for shading a filament of the motor vehicle headlamp, in particular a dim-out cap or a shader, the shading device comprising a sheet-metal part and having a welding lug integrally formed on the edge of the area of the shading device effective for shading, characterized in that the welding lug has a cutout whose edge has essentially the same shape as the edge line, projected onto a plane, of a wall region of the shading device which is opposite the welding lug.

Full Text

Shading device for a motor vehicle headlamp, and method for producing such a shading device The invention relates to a shading device for a motor vehicle headlamp and to a method for producing such a shading device in accordance with the preamble of Patent Claim 1 and Patent Claim 7, respectively. Usually, the shading device is located in the interior of the lamp bulb of a motor vehicle headlamp fitted with two incandescent filaments, specifically the low-beam and high-beam incandescent filaments. Normally, the shading device is a dim-out cap which partially surrounds the low-beam incandescent filament, while the high-beam incandescent filament is arranged outside the dim-out cap. Such a shading device is disclosed, for example, in German Patent DD 224 445. This patent describes a two-filament halogen incandescent lamp having a trough-like dim-out cap for the low-beam incandescent filament. The trough-like dim-out cap has a flat welding lug which is integrally formed on the edge of the dim-out cap and which serves the purpose of welding to an end of the low-beam incandescent filament and, furthermore, is used by the gripper tools of the automatic assembly and production machines,- Here, the welding lug is larger than would be necessary for this purpose, and this entails comparatively high material costs. Usually, a multiplicity of dim-out caps are shaped and blanked in a row for the purpose of producing the dim-out caps from a metal sheet or a sheet-metal strip. In this case, the distance between two successive dim-out caps is greater during blanking than the largest linear dimension of the dim-out cap, with the result that when the dim-out cap is produced a relatively high proportion of the metal sheet remains unused as blanking waste. It is the object of the invention to provide a cost-effective shading device, which saves material, for a motor vehicle lamp and to specify a method for producing such a shading device. This object is achieved according to the invention by means of the characterizing features of Patent Claims 1 and 7, respectively. Particularly advantageous embodiments of the invention are described in the subclaims. In the shading device according to the invention, the welding lug is provided with a cutout whose edge has essentially the same shape as the edge line, projected onto a plane, of a wall region of the shading device situated opposite the welding lug. This measure permits a saving in material of up to 15%, and therefore lowers the production costs for the shading device correspondingly, without serviceability of the shading device thereby being impaired. Furthermore, blanking and shaping the shading device according to the invention does not require an additional work operation. The area of the shading device which is effective for the shading is advantageously domed and, with particular advantage, of trough-like design. As a result, the shading device can be arranged such that it surrounds the filament to be shaded on a plurality of sides. Furthermore, the shading device according to the invention advantageously has a wall region which is referred to as a shader nose, is drawn up by comparison with the remaining wall parts of the shading device, and is situated opposite the welding lug. This drawn-up wall region serves the purpose of more effectively shading the filament, shaded by the shading device, against a second filament arranged outside the shading device. The contour or the edge of the cutout in the welding lug advantageously has the same shape as the edge line, projected onto a plane, of the shader nose. The welding lug of the shading device according to the invention is advantageously provided with a transverse rib which permits projection welding to an end of the shaded filament. The cutout in the shading device according to the invention advantageously extends in this case from the edge of the welding lug up to the transverse rib. The remaining residual webs, arranged on both sides of the cutout and projecting beyond the transverse rib, of the welding lug suffice as a point of attack for the gripper tools of the automatic assembly and production machines. During the production process, a multiplicity of shading devices are shaped and blanked from a metal sheet in a row, the distance between two successive shading devices undergoing blanking from the metal sheet being smaller, according to the invention, than the largest linear dimension of the shading device. In this case, the largest linear dimension of a shading device is defined by the length of the longest side of the rectangle with the smallest circumference which completely encloses the edge line, projected at a scale of 1:1 onto a plane extending parallel to the welding lug, of the shading device - including its welding lug. When the shading devices are blanked, there is produced in the welding lug of each shading device a cutout in which the immediately following shading device already engages. The shader nose of the shading device following next is advantageously shaped in this case from the sheet-metal material blanked from the welding lug of the immediately preceding shading device. The shape or the edge of the cutout in the welding lug is thereby determined by the contour of the shader nose. The invention is explained in more detail below with the aid of a preferred exemplary embodiment. Figure 1 shows a top view of the preferred exemplary embodiment of the shading device according to the invention, Figure 2 shows a sectioned side view of the shading device illustrated in Figure 1, Figure 3 shows a front view of the shading device illustrated in Figure 1, and Figure 4 shows (diagrammatically) a top view of a sheet-metal strip having a plurality of blanked shading devices in accordance with the preferred exemplary embodiment. The preferred exemplary embodiment, illustrated in Figures 1 to 3, of the shading device according to the invention is a dim-out cap 1, consisting of molybdenum, for a motor vehicle headlamp, in particular for a two-filament halogen incandescent lamp. Such lamps are commercially available under the designation H4 lamp. The dim-out cap 1 of the preferred exemplary embodiment of the invention is of trough-like design. It has an essentially flat bottom 2 provided with two welding beads 2a. The dim-out cap further has an essentially flat welding lug 3 integrally formed on its edge. The wall region 4a, opposite the welding lug 3, of the dim-out cap 1 is drawn up by comparison with the remaining wall regions 4b of the dim-out cap 1, and forms the so-called shader nose 4a, which shades the low-beam and high-beam incandescent filaments (not illustrated) from one another. The area effective for shading the low-beam incandescent filament is formed by the bottom 2 and the domed wall regions 4a, 4b of the dim-out cap 1. Leaving aside the welding lug 3 and the welding beads 2a, the shape of the dim-out cap 1 is reminiscent of the hull of a boat. In this comparison, the welding lug 3 would be integrally formed on the stern of the hull, and the shader nose 4a would form the drawn-up bow of the hull. The dim-out cap 1 is mirror-symmetric with respect to the central mirror plane A-A which extends at right angles to the bottom 2 and in the longitudinal direction through the dim-out cap 1. The welding lug 3, integrally formed on the edge of the area 2, 4a, 4b effective for shading, is fitted with a transverse rib 3a which serves the purpose of projection welding to an end of the low-beam incandescent filament. Moreover, the welding lug 3 has a cutout 5, which extends from the edge of the welding lug 3 up to the transverse rib 3a. The edge of the cutout 5 of the welding lug 3 has the same shape or contour as the edge line 6, projected onto a plane, of the shader nose 4a of the dim-out cap 1. A web 7a, 7b projecting beyond the transverse rib 3a and belonging to the welding lug 3 remains in each case on either side of the cutout 5. The webs 7a, 7b are sufficient as a point of attack for the gripper tools of the automatic assembly and production machines. The largest linear dimension of the dim-out cap 1, measured in the linear direction from the shader nose 4a as far as the outer edge, extending at right angles to the mirror plane A-A, of the webs 7a, 7b, measures 12.7 mm. The maximum depth of the cutout 5 is 1.7 mm. The depth of the troughlike dim-out cap 1 is approximately 2.7 mm, leaving the welding beads 2a out of account. The maximum height of the shader nose 4a is approximately 4.1 mm, measured from the bottom 2. The shader nose 4a thus projects beyond the remaining wall regions 4b at a height of approximately 1.4 mm. The dim-out caps 1, 1' and 1" according to the invention are shaped and blanked with the same orientation in a row in the same work operation from a strip 8 of molybdenum sheet (Figure 4) . In the process, the distance between two immediately successive dim-out caps 1, 1' and 1', 1", respectively, is smaller than the largest linear dimension of a dim-out cap 1, 1', 1". During blanking, there is produced in the welding lug 3, 3' of each dim-out cap 1, 1' a cutout 5, 5' in which the immediately following dim-out cap 1', 1" already engages. The shader nose 4a', 4a" of the next dim-out cap 1', 1" is formed in this case from the sheet-metal material blanked from the welding lug 3, 3' of the immediately preceding dim-out cap 1, 1' . The shape of the cutout 5, 5' in the welding lug 3, 3' is therefore determined by the edge of the shader nose 4a', 4a". Since all the dim-out caps 1, 1', 1" are identically shaped, the edge of the cutout 5 in the welding lug 3 thus has the same shape as the edge line 6, projected onto a plane, of the shader nose 4a of the dim-out cap 1. The invention is not restricted to the exemplary embodiment described in detail above. For example, the invention can also be applied to a shader in accordance with the German Patent Application with the official file reference of 19606876.2. We Claim 1. Shading device for a motor vehicle headlamp, for shading a filament of the motor vehicle headlamp, in particular a dim-out cap or a shader, the shading device (1) comprising a sheet-metal part and having a welding lug (3) which is integrally formed on the edge of the area (2, 4a, 4b) of the shading device (1) which is effective for shading, characterized in that the welding lug (3) has a cutout (5) whose edge has essentially the same shape as the edge line (6) , projected onto a plane, of a wall region (4a) of the shading device (1) which is opposite the welding lug (3) . 2. Shading device according to Claim 1, characterized in that the area (2, 4a, 4b) of the shading device (1) which is effective for shading is domed. 3. Shading device according to Claim 2, characterized in that the area (2, 4a, 4b) of the shading device (1) which is effective for shading is of trough-like design. 4. Shading device according to Claim 3, characterized in that the shading device (1) has a wall region (4a) which drawn up by comparison with the remaining wall parts (4b) of the shading device (1) and is situated opposite the welding lug (3). 5. Shading device according to Claim 4, characterized in that the edge of the cutout (5) has the same shape as the edge line (6), projected onto a plane, of the drawn-up wall region (4a). 6. Shading device according to Claim 1, characterized in that the welding lug (3) is fitted with a transverse rib (3a) provided for projection welding, and the cutout (5) extends from the edge of the welding lug (3) up to the transverse rib (3a). 7. Method for producing a shading device for a motor vehicle headlamp, for shading a filament of the motor vehicle headlamp, in particular a dim-out cap or a shader, the shading device (1) having a welding lug (3, 3') which is integrally formed on the edge of the area (2, 4a, 4b), effective for shading, of the shading device, a multiplicity of shading devices (1, 1', 1") being shaped and blanked from a metal sheet (8) in a row, characterized in that during blanking from the metal sheet (8) the distance between similar regions or parts of two successive shading devices (1, 1', 1") is smaller than the largest linear dimension of a shading device (1, 1' , 1") . 8. Method according to Claim 7, characterized in that the wall region (4a', 4a") , opposite the welding lug (3', 3"), of a shading device (1', 1") is shaped from the sheet-metal material blanked from the welding lug (3, 3') of a neighbouring shading device (1, 1') . 9. Shading device for a motor vehicle headlamp substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

1556-del-1997-abstract.pdf

1556-del-1997-claims.pdf

1556-DEL-1997-Correspondence-Others.pdf

1556-del-1997-correspondence-po.pdf

1556-del-1997-description (complete).pdf

1556-del-1997-drawings.pdf

1556-DEL-1997-Form-1.pdf

1556-del-1997-form-13.pdf

1556-del-1997-form-19.pdf

1556-del-1997-form-2.pdf

1556-del-1997-form-3.pdf

1556-del-1997-form-4.pdf

1556-del-1997-form-6.pdf

1556-del-1997-gpa.pdf

1556-del-1997-pct-210.pdf

1556-del-1997-petition-137.pdf

1556-del-1997-petition-138.pdf