GB2279452A - Headlamp for vehicles - Google Patents

Description

2279452 1 Headlaw for vehicles

Prior art

The invention proceeds from a headlamp for vehicles according to the preamble of claim 1.

Such a headlamp is known from DE-Cl 39 39 710. Said headlamp comprises a reflector, a lens disposed at a distance in light direction from"the reflector, and a screen arrangement disposed between the lens and the reflector. The screen arrangement comprises a fixed screen and an adjustable part in the form of a tiltable additional screen. The additional screen is adjustable between two end positions and is provided with an operating element. The additional screen is tiltably supported by means of a pin or a rivet on the fixed screen. Clamped as a spring element between the fixed screen and the additional screen is a pressure spring which loads the additional screen in each case in the direction of an end position. Disposed on the additional screen is a journal which engages into a slot in the fixed screen, with the end positions of the additional screen being determined by the application of the journal against the edge at the end of the slot. The operating element of the additional screen takes the form of a tongue, which projects from the additional screen and upon which a lever pivotally supported on the reflector acts. The lever is of a two-armed construction, one arm acting upon the tongue and the other arm projecting towards the rear of the reflector. For adjustment of the additional screen, the one arm of the operating lever is accessible from the rear of the headlamp. The screen edge of the fixed screen forms a light/dark boundary of the light beam 1 2 exiting from the headlamp. The screen edge of the fixed screen has a horizontal portion and an inclined portion so that the light/dark boundary accordingly extends horizontally on the offside and rises towards the outer edge on the nearside in the manner laid down in statutory regulations for asymmetric low beam. In one end position of the additional screen, its screen edge is disposed below the inclined portion of the screen edge of the fixed screen and therefore does not influence the light beam. In its other end position, the screen edge of the additional screen projects beyond the inclined portion of the screen edge of the fixed screen and forms in stages the light/dark boundary of the light beam exiting from the headlamp. In said position of the additional screen, the screen arrangement has a continuous horizontal screen edge so'that, accordingly, a continuous horizontal light/dark boundary is formed and the headlamp no longer produces an asymmetric low beam. The drawback of this is, however, that the driver's field of vision on the nearside is thereby reduced. The additional screen has to be adjustable in order to enable a motor vehicle fitted with the headlamp to be used for driving on the right and left of the road since, upon changing from driving on the right to driving on the left or vice versa, because the inclined light/dark boundary would then be disposed on the offside, oncoming traffic would be dazzled. The previously described adjustability of the additional screen entails a high outlay since it requires additional parts such as, for example, the pin or rivet for mounting the additional screen and the two-armed operating lever plus its bearing. Said additional parts also mean extra work when assembling the headlamp, which should be avoided to achieve economic manufacture of the headlamp.

Advantages of the invention In contrast, the headlamp according to the invention having the features of claim 1 has the advantage that, owing to the adjustable part of the screen arrangement being supported by 3 means of the knife-edge bearing, no additional component such as a pin or rivet is required and there is also no need to assemble an additional bearing part for the adjustable part of the screen arrangement.

Advantageous refinements and developments of the invention are indicated in the dependent claims. In the construction indicated in claim 2, no additional spring element for the knife-edge bearing is required. Claim 4 indicates a simple construction of-the spring element. By virtue of the construction indicated in claim 6, efficient guiding of the additional screen is achieved without additional components being required for said purpose. The construction according to claim 11 enables the headlamp to be switched between righthand and left-Aand drive with asymmetric light distribution for each position.

Drawings Two embodiments of the invention are illustrated in the drawings and are explained in detail in the following description. Figure 1 shows a headlamp in a vertical longitudinal section with a first embodiment of a screen arrangement; Figure 2 shows the headlamp by sectors in a crosssection along line II-II of Figure 1; Figure 3 shows the headlamp by sectors in a longitudinal section along line IIIIII of Figure 2; and Figure 4 shows the headlamp by sectors in a cross-section along line IIII of Figure 1 with a second embodiment of the screen arrangement.

Description of the embodiments

A diagrammatically represented headlamp for vehicles, in particular for motor vehicles, comprises a reflector 10, which is of an ellipsoidal construction and has an optical axis 11. Inserted into an opening 13 in the apex region of the reflector 10 is a light source 14, which may be an 4 incandescent lamp or a gas discharge lamp. Disposed at a distance in light direction 16 from the front edge 17 of the reflector 10 is a lens 19, which is held in a carrier 20 connected to the reflector 10. In the region of the front edge 17 of the reflector 10, a screen arrangement 22 is disposed in a plane perpendicular to the optical axis 11. The reflector 10 together with the other components may be disposed in a housing 26 with a front opening, which is closed by a transparent cover sheet 28. At its rear, the housing 26 has an opening 29 which is closable by means of a cap 31. Formed on the front edge 17 of the reflector 10 is a radially outwardly directed flange 32 which, in the case of a reflector 10 made of sheet metal, is bent round from said reflector and, in the case of a reflector 10 made of plastic material, is moulded on said reflector. The carrier 20 and the screen arrangement 22 are fastened to the flange 32, e.g. by means of screws or rivets 34.

In a first embodiment shown in Figures 1 to 3, the screen arrangement 22 comprises a fixed screen 23 and a tiltable additional screen 25 as an adjustable part. The fixed screen 23 is fastened to the carrier 20. The fixed screen 23 has a top screen edge 35, which forms a light/dark boundary of the light beam exiting from the headlamp. The screen edge 35 comprises a portion 35a, which extends approximately horizontally and forms the light/dark boundary on the offside of the vehicle, and a portion 35b, which is inclined downwards from the portion 35a and forms the light/dark boundary on the nearside of the vehicle. The light beam exiting from the headlamp therefore, on account of the vertically and horizontally inverted image of the screen edge 35, has a horizontal light/dark boundary on the offside and a light/dark boundary rising towards the road edge on the nearside.

The additional screen 25 is disposed on the side of the fixed screen 23 facing the reflector 10 and is tiltable relative to the screen 23 about an axis 37 extending substantially parallel to the optical axis 11. The swivelling axis 37 of the additional screen 25 is disposed close to the optical axis 11 but may, in principle, be disposed offset relative to the optical axis 11. The additional screen 25 is a sheet-metal part which has a substantially plane main region 40, which extends perpendicular to the optical axis 11 and lies adjacent to a region 41 of the fixed screen 23, which region is likewise substantially plane and extends perpendicular to the optical axis 11. In its main region 40, the additional screen 25 has a top screen edge 43 at the side on which the inclined portion 35b of the screen 23 is formed. Laterally. adjoining the main region 40, the additional screen 25 has, as operating elements, operating levers 44 which project radially beyond the flange 32. Starting from the main region 41, the operating levers 44 are bent initially counter to light direction 16 substantially parallel to the optical axis 11 and then once more substantially radially relative to the optical axis 11. At their end regions 46, the operating levers 44 may be bent once more substantially parallel to the optical axis 11. It is also possible to provide an operating lever 44 at one side only of the additional screen 25. The operating levers 44 may, to reduce their weight, be provided with recesses 47.

The additional screen 25 is supported by means of a knife-edge bearing on a part of the headlamp which is fixed relative thereto. In the embodiment, the screen 23 serves as the fixed part, although the reflector 10 or the carrier 20, for example, could alternatively be used for said purpose. The screen 23 takes the form of a sheet-metal part and a plurality of clip-like holders 49 are set out from its plane main region 41. In the embodiment, a holder 49 is provided on either side of the optical axis 11 and is disposed at a radial distance from the optical axis 11. The holders 49 at their bottom end region are an integral part of the screen 23 and, there, are bent substantially parallel to the optical axis 11 a short way towards the reflector 10 and are then bent back once more 6 parallel to the main region 41, so that the additional screen 25 may be inserted with its main region 40 between the main region 41 of the screen and the holders 44. The holders 49 are directed with their free ends upwards so that the additional screen 25 may be inserted from above.

Approximately in the region of the optical axis 11, a bearing block So is set out from the main region 41 of the screen 23, said bearing block in principle being constructed in the same manner as the holders 49 but being disposed at a greater distance in the direction of the optical axis 11 from the main region 41, with the result that the additional screen 25 is disposed with axial play between the screen 23 and the bearing block 50. The bearing block 50 has, laterally, a substantially V-shaped slot 52 which serves as the step of the knife-edge bearing of the additional screen 25. Bent out of the main region 40 of the additional screen 25 is a lug 53 extending substantially parallel to the optical axis 11, which lug engages into the slot 52 in the bearing block 50 substantially radially relative to the optical axis 11 and serves as the knife edge of the knife-edge bearing.

Hooks 55 and 56 are set out substantially parallel to the optical axis 11 from the main region 40 of the additional screen 25 and the main region 41 of the fixed screen 23 respectively, with both hooks being disposed on the same side of the optical axis 11. The hooks 55 and 56 have, in their sides facing towards one another, a respective recess 58 or 59 into which, in the embodiment, a limb 61 or 62 of a C-shaped spring 64 engages. The spring 64 is preloaded in such a way that, in the fitted state, its limbs 61 and 62 are elastically bent towards one another and have a tendency to move apart from one another. The spring 64 exerts a force acting substantially in a horizontal direction and acts upon the additional screen 25 eccentrically to the latter's knife-edge bearing and holds the latter applied against a stop which determines a first end position of the additional screen 25.

7 Instead of the C-shaped spring 64, a pressure spring clamped between the fixed screen 23 and the additional screen 25 could be used. In the embodiment, the hook 56 set out from the fixed screen 23 serves as a stop for the first end position of the additional screen 25 but any other stop may be provided on the screen 23. By means of the spring 64. moreover, the additional screen 25 is pressed with its lug 53 into the slot 52 in the bearing block 50. thereby securing the knife-edge bearing of the additional screen 25. It is, however, also possible to provide a separate spring for securing the application of the lug 53 in the slot 52.

In Figure 2, the additional screen 25 is shown by solid lines in a first end position, in which its screen edge 43 disposed to the left of the optical axis 11 is disposed below the inclined screen edge portion 35b of the fixed screen 23. In said position, the additional screen 25 is held by the spring 64 applied against the hook 56 of the screen 23 serving as a stop. By virtue of applying a downward-acting force upon the operating lever 44 of the additional screen 25 lying to the right of the optical axis 11 (or, conversely, an upward-acting force upon the operating lever lying to the left of the optical axis 11), the additional screen is moved into its second end position shown by dashed lines in Figure 2. In the process, the additional screen 25 is tilted in its knife-edge bearing about the axis 37, whereupon its lug 53 is swivelled about its end lying adjacent to the base of the slot 52. After a specific swivelling angle about the axis 37, when the hook 55, upon which the limb 61 of the spring 64 acts, is disposed below the swivelling axis 37, the additional screen 25 is pressed by the spring 64 with its region lying to the right of the optical axis 11 downwards into its second end position, in which it comes to lie adjacent to a projection 66 set out as a stop from the screen 23. The projection 66 is disposed - in relation to the optical axis 11 - on the opposite side of the screen 23 to the spring 64, i.e. in Figure 2, to the left of the optical axis 11. During the 8 tilting movement, the additional screen 25 is guided bet7een the holders 49 and the plane main region 41 of the fixed screen 23 in a plane perpendicular to the optical axis 11.

In the second end position of the additional screen 25 shown by dashed lines in Figure 2. its screen edge 43 projects beyond the inclined screen edge portion 35b of the screen 23 and is disposed substantially horizontally. In said end position of the additional screen 25, therefore, a continuous horizontal screen edge is as a whole formed, which comprises the screen edge portion 35a and the screen edge 43. The light beam exiting from the headlamp therefore has, in said end position of the additional screen 25. a continuous horizontal light/dark boundary. Said second end position is adopted by the additional screen 25 when the fixed screen 23 is geared for driving on the right but the vehicle fitted with the headlamp is temporarily being used to drive on the left. The same applies when the screen 23 is geared for driving on the left and the vehicle is temporarily being used to drive on the right.

To adjust the additional screen 25, after removal of the cap 31 a tool, e. g. the end of a screw driver, may for example be inserted through the opening 29 of the headlamp housing 26 and used to act upon one of the operating levers 44 of the additional screen 25. Since the additional screen 25 may only be tilted between its two end positions and cannot adopt intermediate positions, the additional screen 25 need not be visible for adjustment purposes. If direct access to the operating lever 44 of the additional screen 25 in the headlamp housing 26 is impossible or achievable only with difficulty, a setting wheel 70 may be disposed in the headlamp housing 26, said setting wheel having at its periphery a recess 73. which extends substantially radially relative to the axis of rotation 71 of the wheel and into which the end of the operating lever 44 engages. In the embodiment, the setting wheel 70 has, approximately diametrically opposite the recess 9 73,, a further recess 74 into which a tool may be introduced for turning the setting wheel 70. The setting wheel 70 may however be provided with any other point of application for a tool for turning the wheel. Upon turning of the setting wheel 70 the additional screen 25 is tilted, by means of its operating lever 44 engaging into the recess, between its two end positions.

Figure 4 illustrates a second embodiment of the screen arrangement 122, in which parts of an identical or similar construction to those in the first embodiment are provided with reference numerals increased in each case by 100. In the second embodiment, the screen arrangement 122 has only a single, as a whole tiltable screen 123, which is subdivided into a region 125 having the screen edge 135 and a region 127 having the operating levers 144. The region 125 is disposed offset in light direction 16 relative to the region 127, and both regions 125 and 127 are connected to one another by two clips 175 which extend in light direction 16. The screen 123 takes the form of a single sheet-metal part, with the region 125 being set out from the region 127 through bending of the clips 175. The screen edge 135 of the screen-region 125 has, viewed in light direction 16, a right screen edge portion 135a and a left screen edge portion 135b. The two screen edge portions 135a and b are, as in the fixed screen 23 according to the first embodiment, disposed inclined relative to one another. The screen 123 is held on the carrier 120 which, as in the first embodiment, is fastened to the front edge of the reflector and takes the form of a sheet-metal part. The screen 123 is tiltable relative to the carrier 120 about an axis 137 extending substantially parallel to the optical axis 11. The carrier 120 has a substantially plane region 141 extending perpendicular to the optical axis 11, and the screen region 125 is likewise substantially plane and extends perpendicular to the optical axis 11. Projecting laterally from the screen region 127 and projecting radially beyond the flange 32 are the operating levers 144 which, like the operating levers 44 of the additional screen 25 according to the hrst embodiment, are identical in construction.

The screen 123 is supported by means of a knife-edge bearing on a part of the headlamp which is fixed relative thereto. In the second embodiment, the carrier 120 serves as the fixed part. A plurality of clip-like holders 149, e.g. two. are set out from the region 141 of the carrier 120, with there being one holder 149 disposed on either side of the optical axis 11 at a radial distance from said optical axis. The holders 149 are, like the holders 49 of the screen 23 in the first embodiment, identical in construction. The screen region 125 is inserted between the holders 149 and the plane region 141 of the carrier 120. Approximately in the region of the optical axis 11, a bearing block 150 constructed in the same manner as the bearing block 50 in the first embodiment is set out from the region 141 of the carrier 120 towards the reflector. In a corresponding manner to the lug 53 in the first embodiment, a lug 153 is bent out of the screen region 125 towards the reflector, said lug engaging into the slot 152 in the bearing block 150 substantially radially relative to the optical axis 11 and serving as the knife edge of the knife-edge bearing.

Hooks 155 and 156. which extend substantially parallel to the optical axis 11, are set out from the screen region 127 and the region 141 of the carrier 120 respectively, with both hooks 155 and 156 being disposed on the same side in relation to the optical axis 11. As in the first embodiment, the hooks 155 and 156 each have a recess, into which a limb 161 or 162 of a C-shaped spring 164 engages. The spring 164 is preloaded in such a way that its limbs 161, 162, in the fitted state, are elastically bent towards one another and have a tendency to move apart from one another. The spring 164 exerts a force acting substantially in a horizontal direction and acts upon the screen region 125 eccentrically to the latter's knife-edge bearing and holds the latter applied against a stop which 11 determines a first end position of the screen 123. Instead of the C- shaped spring 164, a pressure spring clamped between the region 141 of the carrier 120 and the screen region 125 could be used. The feet of the holders 149 set out from the region 141 of the carrier 120 serve as a stop for the end positions of the screen 123. By means of the spring 164, the lug 153 of the screen region 125 is simultaneously pressed into the slot 152 of the bearing block 150, thereby securing.the knife-edge bearing of the screen 123. It is however also possible to use a separate spring for securing the application of the lug 153 in the slot 152.

In Figure 4, the screen 123 is shown by solid lines in its first end position, in which its - viewed in light direction 16 - left screen edge portion 135b is disposed in a downward inclined manner and its right screen edge portion 135a is disposed substantially horizontally. In said position. the screen 123 is held by the spring 164 with its screen region 125 applied against the foot of the holder 149 disposed - in Figure 4 - to the left of the optical axis 11. The light beam emitted by the headlamp in said first end position of the screen 123 accordingly has, on the left side, a horizontal light/dark boundary formed by the screen edge portion 135a and, on the right side, an upward rising light/dark boundary formed by the screen edge portion 135b.

By virtue of applying a downward-acting force upon the operating lever 144 disposed to the right of the optical axis 11, or conversely an upwardacting force upon the operating lever 144 disposed to the left of the optical axis 11, the screen 123 is moved into its second end position shown by dashed lines in Figure 4. In the process, the screen 123 is tilted in its knife-edge bearing about the axis 137. whereupon its lug 153 is swivelled about its end lying adjacent to the base of the slot 152. After a specific swivelling angle about the axis 137, when the hook 155 of the screen region 127, upon which the limb 161 of the spring 164 acts, is disposed below i 12 the axis 137, the screen 123 is pressed by the spring 164 with its region lying to the right of the optical axis 11 downward into its second end position, in which it comes to lie with its screen region 125 applied against the foot of the right holder 149 as a stop. During the tilting movement, the screen 123 is guided by means of its screen region 125 between the holders 149 and the plane region 141 of the carrier 120. In the second end position of the screen 123, its - viewed in light direction 16 - left screen edge portion 135b is disposed substantially horizontally and its right screen edge portion 135a is inclined downwards. Accordingly, the light beam exiting from the headlamp has, on the left side, an upward rising light/dark boundary formed by the screen edge portion 135a and, on the right side, a substantially horizontal light/dark boundary formed by the screen edge portion 135b. In the case of the screen arrangement 122, it is therefore possible to switch between an asymmetric light distribution for driving on the right, corresponding to the first end position of the screen 123, and an asymmetric light distribution for driving on the left, corresponding to the second end position of the screen 123.

The use, as described previously with reference to the first embodiment, of a setting wheel 70 which acts upon the operating lever 44 of the adjustable part of the screen arrangement is likewise possible in the second embodiment of the screen arrangement.

13 claims Headlamp for vehicles, having a reflector (10), a lens (19) disposed at a distance in light direction (16) from the reflector, and a screen arrangement (22; 122) disposed between the lens and the reflector (10), of which arrangement at least one part (25; 123) is adjustable between two end positions, is tiltably supported on a part (23; 120) of the headlamp which is fixed relative to the adjustable part (15; 123) of the screen arrangement (22; 122), has an operating element (44; 144) and is loaded by a spring element (64; 164) at least towards one of the two end positions, with the screen arrangement (22; 122) producing a light/dark boundary of the light beam exiting from the headlamp, characterized in that the adjustable part (25; 123) of the screen arrangement (22; 122) is supported by means of a knife-edge bearing (52, 53; 152, 153) on the fixed part (23; 120), with the application of the adjustable part (25; 123) of the screen arrangement (22; 122) against the fixed part (23; 120) in the knife-edge bearing being effected by a spring element (64; 164).

2. Headlamp according to claim 1, characterized in that the adjustable part (25; 123) of the screen arrangement (22; 122) is held applied in the knife-edge bearing by the spring element (64; 164).

3. Headlamp according to claim 1 or 2, characterized in that the fixed part (23; 120) of the headlamp has a bearing block with a step (52; 152) forming one part of the knife-edge bearing, and the adjustable part (25; 123) of 14 the screen arrangement (22; 122) has a knife-edge (53; 153) forming the other part of the knife-edge bearing, which engages into the step (52; 152).

4.

Headlamp according to one of claims 1 to 3, characterized in that the spring element (64; 164) is a spring bent substantially into a C-shape which is supported with one limb (61; 161) on the adjustable part (25; 123) of the screen arrangement (22; 122) and with its other limb (62; 162) on a part.(23; 120) of the headlamp which is fixed relative to the adjustable part (25; 123).

5. Headlamp according to claim 4, characterized in that the spring element (64; 164) acts upon the adjustable part (25; 123)of the screen arrangement (22; 122) eccentrically to the knife-edge bearing in such a way that the adjustable part (25; 123) is held by the spring element (64; 164) in both end positions against a stop (56, 66; 156, 166).

6. Headlamp according to one of the preceding claims, characterized in that a part (23; 120) of the headlamp, which is fixed relative to the adjustable part (25; 123) of the screen arrangement (22; 122), has a substantially plane region (41; 141) and the adjustable part (25; 123) has, facing said region, a likewise substantially plane region (40; 125) and that the fixed part (23; 120) has clip-like holders (49; 149), between which and the substantially plane region (41; 141) of the fixed part (23; 120) the substantially plane region (40; 125) of the adjustable part (25; 123) is held in the direction of the optical axis (11).

1.

Headlamp according to claim 6, characterized in that the holders (49; 149) have a bottom end region extending at the fixed part (23; 120) substantially parallel to the optical axis (11) and a free, upwarddirected end region extending substantially parallel to the substantially plane region (41; 141) of the fixed part (23; 120), with the substantially plane region (40; 125) of the adjustable part (25; 123) of the screen arrangement (22; 122) being held between the free end regions and the substantially plane region (41; 141) of the fixed part (23; 120).

Headlamp according to claim 6 or 7, characterized in that the fixed part (23; 120) of the headlamp is a sheet-metal part, from which the clip-like holders (49; 149) are set out.

9. Headlamp according to one of the preceding claims, 3 characterized in that the screen arrangement (22) comprises a fixed screen (23) having a screen edge (35) with a horizontal portion (35a) and an inclined portion (35b) and, as an adjustable part, an additional screen (25) having a screen edge (43), with, in the first end position of the additional screen (25), its screen edge (43) being disposed below the inclined screen edge portion (35b) of the fixed screen (23) and, in the second end position of the additional screen (25), its screen edge (43) being disposed substantially horizontally above the inclined screen edge portion (35b) of the fixed screen (23).

10. Headlamp according to claim 9, characterized in that the fixed screen serves as the fixed part (23) of the headlamp.

Headlamp according to one of claims 1 to 8, characterized in that the screen arrangement (122) comprises a single, as a whole adjustable screen (123) having a screen edge (135) with portions (135a, b) disposed inclined relative to one another, with, in the first end position of the screen (123), its - viewed in light direction (16) - 16 right screen edge portion(135a) being disposed substantially horizontally and its left screen edge portion (135b) being disposed in an inclined manner and, in the second end position of the screen (123), its right screen edge portion (135a) being disposed in an inclined manner and its left screen edge portion (135b) being disposed substantially horizontally.

12. Headlamp according to one of the preceding claims, characterized in that the reflector (10), the screen arrangement (22; 122) and the lens (19) are disposed in a housing (26), that the housing (26) has at its rear an opening (29), and that there is rotatably supported in the housing (26) a setting element (70), which acts upon the operating element (44; 144) of the adjustable part (25; 123) of the screen arrangement (22; 122) and may be turned by means of a tool insertable through the opening (29) of the housing (26) in order to effect tilting of the adjustable part (25; 123).

13. Either of the headlamps substantially as herein described with reference to the accompanying drawings