Abstract:
A headlight for a motor vehicle has a light module with at least one reflector and a light source, a first frame with which at least a part of the light module is connected, a first adjusting element for swivelling the first frame around a first swivel axis, a second frame in which the first frame is supported and which is turnable around a second swivel axis, a second adjusting element for swivelling the second swivel frame, a body-fixed frame support in which the second frame is supported, the frames being arranged so that the swivel axes extend perpendicular to one another and arranged in one plane, a base adjustment element for adjusting at least one of the frames around an adjusting axis which is aligned with one of the swivel axis.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention generally relates to headlights for vehicles  
           [0002]    More particularly, it relates to a headlight for a vehicle, in particular a motor vehicle, which has a light module with at least one reflector, a light source and an optional projection optical system, wherein at least a part of the light module is connected with a first frame. The first frame is swivable about a first swivelling axis by a first adjusting means supported in a second frame, wherein the second frame is swivable by a second adjusting means about a second swivelling axis supported in a body-fixed frame carrier. The swiveling axes are arranged perpendicular to one another in one plane, and at least one of the frames is adjustable by a base adjusting means around an adjusting axis.  
           [0003]    Headlights to be used in vehicles have in conventional constructions, a light source, a reflector and a cover member with or without a dispersion optical system. The headlights of this type have a disadvantage that the reflectors require a relatively significant space to provide a satisfactory quality or brightness of the low beam. From design and flow-technique reasons, it is however desired to reduce the mounting space required for a headlight. This can be achieved for example by the use of so-called PES (poly-ellipsoid system). PES-headlights have a low beam optical system which projects the light produced by the light source and reflected by the reflector onto the roadway in front of the vehicle. With the PES system the mounting space occupied by the headlight is significantly reduced when compared with conventional headlights.  
           [0004]    It is known to arrange headlights or parts of the headlight of the vehicle (the light module) movable relative to the vehicle body, for turning the headlight or parts of the headlight. For example the headlight or parts of the headlight can be turned about a horizontal swiveling axis to adjust the light range in the vertical direction. In Europe all new vehicles which are produced since Jan. 1, 1999 must have a light range regulation or a manually operated light range adjustment.  
           [0005]    It is further known to arrange headlights or parts of the headlights swivelable about a second additional swiveling axis. For example the second swiveling axis can be arranged vertically to turn the light outlet direction of the headlight in a horizontal direction. With sufficiently large swiveling angles for example up to +/−15°, it is possible to execute a curve light operation. Thereby the light outlet direction of a headlight can be adjusted to a radius of a curve over which a vehicle is driving, to obtain an optimal illumination of the roadway, in particular over curves with a small curve radius.  
           [0006]    It is known to support a headlight or parts of the headlights by cardans which simultaneously allow both a light range regulation and also a curved light operation. It is in particular known to design the cardan bearing so that at least a part of the headlight is connected with a first frame which is supported swivelably in a second frame, which is also supported swivelably in a body-fixed frame carrier.  
           [0007]    It has been recognized that it is advantageous when the swiveling axes intersect in one point, and the intersection point of the axes from dynamic reasons can not be arranged in the vicinity of a center of gravity of headlight parts to be supported. By swiveling of the headlight parts around two intersecting axes the dimensions of gaps which occur between the movable parts of the headlight and the body-fixed parts which adjoin the movable headlight parts can be reduced. Such a headlight is disclosed for example in the pending and not published patent document DE 101 29 968.  
           [0008]    For compensation of manufacturing tolerances, it is necessary to bring the headlight or the headlight parts at the end of the complete mounting of the vehicle to a base adjustment, in particular to satisfy the adjusting requirements which are prescribed in accordance with corresponding regulations. For this purpose base adjustment means are provided, with which the headlight or parts of the headlight are adjustable around an adjusting axis. The base adjusting means which are used for this purpose include adjusting screws which are for example in toothed engagement with the headlight or parts of the headlight via transmission elements.  
           [0009]    It has been determined that in known headlights it is disadvantageous that the base adjustment of the headlight is possible only with a relatively large, disturbing gaps between vehicle-fixed and movable headlight parts.  
         SUMMARY OF THE INVENTION  
         [0010]    Accordingly, it is an object of the present invention to provide a headlight of the above mentioned general type, which avoids the disadvantages of the prior art.  
           [0011]    More particularly, it is an object of the present invention to provide a headlight which can be operate with a curve light function and a light range regulation, wherein an independent base adjustment of the headlight is possible with lowest possible curve dimensions between movable and vehicle-fixed parts of the headlight.  
           [0012]    In order to achieve these objects, the adjusting axis is arranged so that it is aligned with one of the swiveling axes.  
           [0013]    Since the adjusting axis is aligned with one of the swiveling axes, small gap dimension between movable and vehicle-fixed parts of the headlight is obtained with the cardanic suspension of the headlight or the headlight parts, without increasing the gap dimension for allowing the base adjustment.  
           [0014]    With the proposed arrangement, the movable headlight parts are arranged so that their outer surfaces which are spaced the farthest from the intersection point of the swiveling axes, during their turning describe the surface of a sphere. The vehicle-fixed headlight parts adjoining the movable parts of the headlight, for example optical screens, can be arranged so that they directly adjoin a remaining minimum gap. With the spherical movement of the headlight parts, a gap formed by the distance between the movable and vehicle-fixed headlight parts remains constant. This is especially advantageous when for carrying out a curve light operation relatively great swiveling angle of +/−15° is required.  
           [0015]    In accordance with a further embodiment of the present invention, the first and the second frames are adjustable correspondingly through base adjusting means around corresponding adjustment axes. The adjusting axes are arranged in alignment with the turning axes.  
           [0016]    This arrangement guarantees that a base adjustment of the vehicle headlight can not be performed in horizontal and vertical directions without a large gap dimension between movable and vehicle-fixed headlight parts. For example a first frame is provided, on which the movable parts of the headlights, for example a light source, a reflector and/or a projection optical system are mounted. This first frame is horizontally swivelable about a first, vertical swiveling axis by means of a first adjusting means. Thereby a curve light operation can be executed. This first frame is arranged in a second frame which surrounds the first frame, which is swivelable about a second, horizontal swiveling axis by means of a second adjusting means. Thereby a light range regulation is possible. The second frame is supported in a body-fixed frame carrier.  
           [0017]    In order to provide the base adjustment of the first and the second frames, the base adjustment means are provided. They are arranged in accordance with the present invention so that the adjusting axes around which the frames can swivel for their base adjustment are in alignment with the swiveling axes for swiveling the frames for executing the curve light function or the light range regulation. This arrangement allows to reduce the gap it between the movable and vehicle-fixed headlight parts to a minimum value.  
           [0018]    In accordance with another embodiment of the invention, it is provided that base adjustment means operate between the frame carrier and the first frame and/or between the frame carrier and the second frame, and the base adjustment means adjusts the relative position of the first adjusting means to the first frame and/or the relative position of the second adjusting means to the second frame. The base adjustment means are arranged so that a swiveling of the first and second frames is not performed as in conventional systems by a direct action of the base adjustment means on the frames, but instead with interposition of the adjusting means. The base adjustment means provide the position and orientation of the adjustment means which thereby assume a predetermined relative position relative to the first and the second frames.  
           [0019]    Advantageously the adjusting means each have an adjustment means drive and a stroke means connected with a frame through a hinge. The adjusting means drive can be activated for example pneumatically, hydraulically or electrically and stroke means can be formed as pistons. Such adjusting means and stroke means are advantageous and known from a plurality of industrial applications.  
           [0020]    In accordance with a further embodiment of the present invention, the base adjustment means have correspondingly a base adjustment drive with a coupled first transmission member which is swivelable about a frame carrier-fixed axis. This first transmission member can support an adjustment means drive, wherein by swivelling the first transmission member a frame-fixed axis of this adjustment means drive is swivelable also to adjust the relative position between the adjusting means drive and one of the frames. For example, the first transmission member of the adjusting means drive carries the corresponding adjustment means, with which a frame is swivelable for light range regulation vertically about a horizontal swiveling axis.  
           [0021]    In accordance with a further embodiment of the present invention, the first transmission member is coupled to a second transmission member, which carries an adjustment means drive and a first frame-fixed axis. For example via a base adjustment drive, a coupled first transmission member which is swivellable about a frame carrier-fixed axis can be swivelled. Thereby, a second transmission member which is coupled to the first transmission member is swivellable about a further axis, wherein the further axis is frame-fixed or in other words is arranged in one of the swivellable frames. These two transmission members can support as adjustment means drive, with which for example a frame is swivellable about a vertical swivelling axis in a horizontal direction. With the above described arrangement it is possible to swivel the second transmission member via the base adjustment drive and the first transmission member and thereby to adjust the adjusting means which is fixedly connected with the second transmission member, in its relative position relative to one of the frames.  
           [0022]    Advantageously one of the two transmission members have a coulisse guide and the other transmission member has a pin which engages in the coulisse guide. Such a support provides a gap-free movement transmission in one plane. This movement transmission is required for bringing one of the two frames to its base position. With the special design and connection between the first and second transmission members by means of the coulisse guide and the engaging pin it is achieved that the second transmission member is kinematically coupled with respect to the first transmission member in a perpendicular plane for a gap-free movement transmission.  
           [0023]    In accordance with the present invention the base adjustment drive and the first transmission member are connected with one another through a self-locking screw hinge. Thereby after finishing of the base adjustment, the base adjustment member and the first transmission member are retained in the selected position. Thereby also the base adjustment of a coupled frame is determined.  
           [0024]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    [0025]FIG. 1 is a perspective view of a part of a headlight in accordance with the present invention;  
         [0026]    [0026]FIG. 2 is a perspective view of the arrangement of FIG. 1 as seen in observation direction A;  
         [0027]    [0027]FIG. 3 is a view showing a portion of the arrangement of FIG. 1 on a plan view as seen in observation direction B;  
         [0028]    [0028]FIG. 4 is a longitudinal section through a PES headlight in accordance with the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]    [0029]FIG. 1 is a perspective view of a headlight in accordance with the present invention. It is provided with an outer frame carrier  2  which is fixed with a body and serves for receiving all parts which will be described herein below. An outer frame  4  is supported in the frame carrier  2 , and an inner frame  6  is supported in the outer frame. The outer frame  4  is connected with the frame carrier  2  through bearing pins  8  and  10 , so that the outer frame can be swivellable around a horizontal swivelling axis H.  
         [0030]    Pin guides  12  and  14  are provided in the outer frame  4  and formed for engagement by pins  16 ,  18  which are integral with the inner frame  2 . Hinges are formed by the pin  16 ,  18 , and the pin guides  12 ,  14 , for swivelling the inner frame  6  around a vertical axis V relative to the outer frame  4 . The inner frame  6  is provided for firmly receiving not shown parts of the vehicle, such as for example a light source and a reflector and/or a projecting optical system (so-called light module). These parts are moved together with movement of the inner frame.  
         [0031]    A light range adjusting means drive  10  is provided for driving a stroke piston  22 . The stroke piston  22  is mounted on a transmission pin  24  which is guided in a pin guide  26 . The pin guide  26  is formed by a lever  28  which is fixedly connected with the outer frame  4 . The outer frame  4  can be swivelled around the horizontal swivelling axis H relative to the frame carrier  2  via the light range adjusting means drive  20 , the stroke piston  22 , the transmission pin  24 , the piston guide  26  and the lever  28 . With such a swivelling, a light range regulation is executed.  
         [0032]    The arrangement shown in FIG. 1 further has a curve light adjusting means drive  30  which operates for driving a stroke piston  32 . The stroke piston  32  is connected with a transmission rod  36  through a spherical hinge  34 . The transmission rod  36  is connected with the inner frame  6  through a hinge  38 . A turning of the inner frame  6  around the vertical turning axis V relative to the outer frame  4  is performed via the curve light adjusting means drive  30 , a stroke piston  32 , the spherical hinge  34 , the transmission rod  36  through the hinge  38 . With such a swivelling, a curve light function is executed.  
         [0033]    An adjustment of the inner frame  36  in a horizontal and vertical directions is possible with the above described parts. The adjustment in the horizontal direction is performed by swivelling of the inner frame  6  around the vertical turning axis V in the outer frame  4 . The swivelling in a vertical direction is performed by swivelling of the outer frame  4  around the horizontal turning axis H. Thereby the light-generating elements of the headlight which are mounted on the inner frame  6  (light module) are brought to a position which is required for execution of both functions, namely “curve light regulation” or “light range regulation”.  
         [0034]    [0034]FIG. 2 shows an arrangement of FIG. 1 as seen in observation direction A. The frame carrier  2 , the outer frame  4 , as well as the inner frame  6  can be seen in this drawing. Furthermore, the above described light range adjusting means drive  20  as well as the stroke pin  22 , the transmission pin  24 , the pin guide  26  and the lever  28  mounted on the outer frame  4  are shown in this drawing.  
         [0035]    The light range adjusting means drive  20  is fixedly connected with a swivel carrier  40 . The swivel carrier  40  is swivellable about a swivelling axis  42 . For this purpose the swivel carrier  40  is coupled to the frame carrier  2  in a frame carrier-fixed bearing  44 . The swivel carrier  40  is swivellable around the axis  42 . In particular, by driving a threaded spindle  46  in a screw hinge  48  a turning displacement movement is produced, which swivels a swivel carrier  40  around the axis  42 . Since the screw hinge  48  is moveable along a periphery around the frame carrier-fixed bearing  44 , the threaded spindle  46  is formed bendable to avoid a canting between the threaded spindle  46 , the swivel carrier  40  and the frame carrier  2 .  
         [0036]    For driving the threaded spindle  46 , a spindle drive  50  is provided. It has for example adjusting screws which can be turnable to produce the turning movement of the threaded spindle  46 . The spindle drive  50  can be supported, for example, through hinge shafts at a location which is far from the headlight. The light range adjusting means drive  20  can be brought to a base position via the spindle drive  50 , the thread spindle  46  and the swivel carrier  48 . The outer frame  40  can be brought to a base position by coupling through the stroke piston  22  and the lever  28 . Thereby the outer frame  40  swivels about the same horizontal axis H, about which the outer frame  4  is swivellable during driving of the light range adjusting means drive  20 .  
         [0037]    [0037]FIG. 3 shows a portion of the arrangement of FIG. 1 as seen in observation direction B. The curve light adjusting means drive  30  is mounted on a swivel plate  52 . The swivel plate  52  has a bearing ring  54  which is supported swivellably around the pin guide  14  of the outer frame  4 . The stroke piston  32 , the spherical hinge  34 , the transmission rod  36  and the hinge  34  are visible, which are formed integrally with the inner frame  6 . The inner frame  6  is supported swivellably via the pin  18  in the pin guide  14  of the outer frame  4 . The second adjusting means drive  30  and thereby the inner frame  6  can be brought via the elements  32 - 38  to a base position. This is performed by swivelling the swivel plate  52  around the pin guide  14 . For this purpose a threaded spindle  56  is provided, which can be driven by a not shown spindle drive. This threaded spindle  56  is connected with a turning lever  60  through a screw hinge  58 . The turning lever  60  is turned around a frame carrier-fixed bearing  62  so that during driving of the threaded spindle  56  a rotary displacing movement in the screw hinge  58  is performed. The lever  60  has a pin  64  which engages in a coulisse guide  66  formed in the swivel plate  52 .  
         [0038]    When the lever  60  during driving of the threaded spindle  56  is turned around the frame carrier-fixed hinge  62 , the pin  64  describes a circular path  68 . With the engagement of the pin  64  in the coulisse guide  66 , the swivel plate  52  is swivelled and in particular about the vertical swivel axis V arranged perpendicular to the plane of the drawing. Since the swivel plate  52  is swivellable around the vertical swivel axis V, the curve light adjusting means drive  30  and thereby the inner frame  6  are brought through the elements  32 - 38  to a base adjustment. The frame  60  is swivellable around the same vertical axis V, around which the frame  6  can swivel by actuation of the curve light adjusting means drive  30 .  
         [0039]    [0039]FIG. 4 shows a section of the headlight elements for fixed arrangement of the inner frame  6  shown in FIGS. 1 and 2. In FIG. 4 a light source  100  is shown, which provides the light beam reflected by a reflector  102 . Furthermore, light screen elements  104  are shown for obtaining a predetermined bright-dark limit during projection from the light source  100 , and for producing the light beams deviated by the reflector  102 .  
         [0040]    The arrangement shown in FIG. 4 further has a projection optical system  106  which adjoins the co-moving screens  108 ′,  108 ″′. The w-moving screens  108 ′,  108 ″ have screen edges  110 ′,  110 ″, which extend circularly in the view of FIG. 4 showing the PES headlight in direction of observation C. The projection optical system  106  is shown in FIG. 2 by solid lines, in which the screen edges  110 ′,  110 ″ have a central position  0 ′,  0 ″. The projection optical system  106  can be swivelled from the central position  0 ′,  0 ″ around a central point Z in counter clockwise direction over 14°, so that the screen edges  110 ′,  110 ″ assume an extreme position identified as I′, I″. Such a significant swivelling of the projection optical system  106  can be required for example during driving over a curve with a small radius.  
         [0041]    The projection optical system  106  can be moved also from the central position  0 ′,  0 ″ to a position in which the screen edges  110 ′,  110 ″ assume a second extreme position identified as II′, II″.  
         [0042]    [0042]FIG. 4 also shows body-fixed covers  112 ′,  112 ″. A gap  114 ′is formed between the body-fixed cover  112 ′ and the moving screen  108 ′. A gap  114 ″ is formed between the body-fixed cover  112 ″ and the moving screen  108 ″. It can be clearly seen that the gap sizes  114 ′,  114 ″ have the same size which is not dependent on whether the projecting optical system  106  and the moving screens  108 ′ or  108 ″ are located in their central position zero or located in their extreme positions I, II. The gaps  114 ′,  114 ″ can be selected as small as possible so that the projection optical system  106  is moved around the central point Z. This is possible since the projection optical system  106  is movable around the same central point Z both for the base adjustment and also for the light range or curve light adjustment in normal operation of the headlight. The view shown in FIG. 4 is applicable both for a horizontal and also for a vertical section plane through the PES headlight. For a horizontal section plane the extreme positions I and II constitute curve light positions. For a vertical section plane the extreme positions I or II constitute extreme light range positions.  
         [0043]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.  
         [0044]    While the invention has been illustrated and described as embodied in headlight, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
         [0045]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.  
         [0046]    What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.