Abstract:
Vehicle headlight including a light emitting unit for emitting a light, an operating member joined with the light emitting unit, the operating member fitted with a magnet, a coil in the vicinity of the operating member for generating a magnetic field, and a housing for holding the operating member and the coil therein, thereby permitting selective lighting of a high beam for regular running at night or a low beam required in crossing an opposite vehicle by using a single light emitting unit and a simple structure.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to vehicle headlights, and more particularly, to a vehicle headlight, in which a simple light emitting unit is employed for selective lighting of a high-beam at night or a low-beam during crossing with an oncoming vehicle.  
           [0003]    2. Background of the Related Art  
           [0004]    In general, the headlights, mounted on the front of a vehicle to ensure an adequate field of view of a driver when driving the-vehicle at night, are required to have a luminance specified by law, and not to obstruct the vision of oncoming drivers.  
           [0005]    That is, the headlight is required to form a running beam (so called an upper direction beam, or a high beam) for securing a long range of view during regular running, and a crossing beam (so called a low direction beam, or a low beam) when crossing with an oncoming vehicle so as to prevent the light beams from obstructing the vision of oncoming drivers while securing a certain extent of range of view.  
           [0006]    A halogen lamp is widely used in a conventional headlight. The halogen lamp is provided with two filaments, that is, a filament for irradiating a high-beam and a filament for irradiating a low-beam, so a high-beam mode or a low-beam mode may be selectively operated as desired. In this case, the filament for irradiating a low-beam is installed inside the vessel-shaped lamp.  
           [0007]    However, when the halogen lamp, which is provided with two filaments, is compared with a gas-discharge lamp which is widely used now, the halogen lamp is inferior in performance to the gas-discharge lamp. Thus, there is a growing tendency to use the gas-discharge lamp for a headlight, because the gas-discharge lamp radiates white light, which is about three times as bright as the conventional halogen lamp, thus making it easy to distinguish objects, and uses two-thirds of the halogen lamp&#39;s electric consumption, and is semi-permanent. However, since only one gas-discharge lamp is installed in such a headlight, there is restriction, imposed on the design of the headlight.  
           [0008]    That is, it is impossible to develop a gas-discharge lamp having two filaments, that is, two light emitting units so as to irradiate both a high beam and a low beam, so the above-mentioned problem occurs.  
           [0009]    In order to overcome such a problem, there has been proposed a method where a light emitting unit is operated by a small-sized motor to instantaneously move upward or downward. However, such a method has a problem that it has a complicated mechanical mechanism because the rotating movement of the motor must be converted into a rectilinear movement, the manufacturing cost is increased, and the operation is slow. For these reasons, the gas-discharge lamp is not widely used in the headlight.  
         SUMMARY OF THE INVENTION  
         [0010]    Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a vehicle headlight which has a simple construction and selectively irradiates a high-beam when driving a vehicle at night or a low-beam so as to prevent light beams from obstructing the vision of oncoming drivers, using a single light emitting unit.  
           [0011]    In order to accomplish the above object, the present invention provides a vehicle headlight which is designed such that a single light emitting unit is operated by the operation of an ON/OFF switch to irradiate a low-beam when driving the vehicle at night, and the light emitting unit is rapidly moved toward a coil, according to Fleming&#39;s left-hand law, by the magnetic field of the coil and a magnet by operating a dimmer switch when necessary so that a focus of the light emitting unit precisely corresponds with a focus of a parabolic reflecting mirror, thus allowing the operating mode of the headlight to be easily changed into a high-beam mode, therefore allowing the headlight to selectively irradiate the low-beam or the high-beam.  
           [0012]    In another aspect of the present invention, there is provided a vehicle headlight including a light emitting unit for emitting a light, an operating member joined with the light emitting unit, the operating member fitted with a magnet, a coil in the vicinity of the operating member for generating a magnetic field, and a housing for holding the operating member and the coil therein.  
           [0013]    The operating member is movable in a horizontal direction. The coil is preferably fitted adjacent to the magnet in a horizontal direction, and elastic means is fitted between the magnet and the coil, and more preferably the elastic means is a compression spring.  
           [0014]    Preferably, the vehicle headlight further includes a guide member for guiding a horizontal movement of the light emitting unit, and the guide member is cylindrical. Preferably, the guide member serves as a shield.  
           [0015]    Preferably, the operating member is movable in a vertical direction. The coil is fitted in the vicinity of the magnet in a vertical direction, and preferably elastic means is fitted between the magnet and the coil.  
           [0016]    The housing includes a control rib at an inside wall and a mounting boss on an upper part, the mounting boss fitted with the coil, and the operating member includes a support part having hinge shafts rotatably fitted to the housing, and a support bar having one side connected to the support part and the other side having the magnet fitted thereon. The moving distance of the operating member is preferably in a range of 5˜7 mm.  
           [0017]    A position of the operating member may be shifted selectively by changing a direction of a current to the coil.  
           [0018]    In further aspect of the present invention, there is provided a vehicle headlight including a light emitting unit for emitting a light, an operating member joined with the light emitting unit, the operating member fitted with a magnet, a magnet in the vicinity of the operating member, and a housing for holding the operating member and the coil therein. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:  
         [0020]    [0020]FIG. 1 is a perspective view showing a headlight in accordance with a preferred embodiment of the present invention;  
         [0021]    [0021]FIG. 2 is an exploded perspective view of the headlight in FIG. 1;  
         [0022]    [0022]FIGS. 3A and 3B are sectional views of the headlight in FIG. 1, wherein,  
         [0023]    [0023]FIG. 3A shows the headlight in a low-beam state, and  
         [0024]    [0024]FIG. 3B shows the headlight in a high-beam state;  
         [0025]    [0025]FIGS. 4A and 4B are sectional views each showing a state a headlight mounted to a vehicle in accordance with a preferred embodiment of the present invention, wherein  
         [0026]    [0026]FIG. 4A shows the headlight in a low beam state, and  
         [0027]    [0027]FIG. 4B shows the headlight in a high beam state;  
         [0028]    [0028]FIG. 5 is a perspective view showing a headlight in accordance with another preferred embodiment of the present invention;  
         [0029]    [0029]FIG. 6 is an exploded perspective view of the headlight in FIG. 5;  
         [0030]    [0030]FIGS. 7A and 7B are sectional views of the headlight in FIG. 5, wherein,  
         [0031]    [0031]FIG. 7A shows the headlight in a low-beam state, and  
         [0032]    [0032]FIG. 7B shows the headlight in a high-beam state;  
         [0033]    [0033]FIGS. 8A and 8B are sectional views each showing a state a headlight mounted to a vehicle in accordance with a preferred embodiment of the present invention, wherein  
         [0034]    [0034]FIG. 8A shows the headlight in a low beam state, and  
         [0035]    [0035]FIG. 8B shows the headlight in a high beam state. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
         [0037]    An embodiment of the vehicle headlight of the present invention will be described with reference to FIGS.  1 ˜ 3 .  
         [0038]    As shown in the drawings, a headlight according to the present invention includes a cylindrical housing  10  which has a space  11  for receiving several components therein. A coil  30  is fixedly provided in the space  11  at a position adjacent to a rear end of the housing  10 . A cover  20  closes the rear end of the housing  10 .  
         [0039]    A support cap  80  is mounted to a front end of the housing  10  so as to support the housing  10  and ensure that the housing  10  is stably mounted to a parabolic reflecting mirror. A hole  81  is formed at a center of an end wall of the support cap  80  in such a way that a light emitting unit  70  is axially projected through the hole  81 . Three radial locking pieces  82  are provided at three predetermined positions along a sidewall of the support cap  80 . Thus, the light emitting unit  70  moves in and out the housing  10  through the hole  81  of the support cap  80 .  
         [0040]    It is preferable that a guide unit  90  is mounted to the support cap  80  to smoothly guide the movement of the light emitting unit  70 . The guide unit  90  is mounted to the end wall of the support cap  80  using a setscrew S. The guide unit  90  is provided with a semi-cylindrical guide  91 . The guide  91  surrounds a part of an outer circumferential portion of the light emitting unit  70  in such a way as that the light emitting unit  70  is slidably moved in and out the hole  81  of the support cap  80 . The guide member  90  can also serve as a shield for forming a cut off line in lighting the low beam. Of course, the shield may be fitted separately.  
         [0041]    Further, according to the present invention, a operating member  50  is provided in the space  11  of the housing  10  at a position adjacent to the front end of the housing  10 , and axially holds an inside portion of the light emitting unit  70 . A holding step  51  is formed at an inside end of the operating member  50  to hold an end of the compression spring  40 . A magnet  60  is mounted to an inside end of the holding step  51  so as to move the operating member  50  with the light emitting unit  70  rearward due to a magnetic field.  
         [0042]    That is, the coil  30  and the magnet  60 , which are provided in the space  11  of the housing  10  in such a way as to be adjacent to the rear end of the housing  10 , cooperate with each other to pull the operating member  50  along with the light emitting unit  70 , thus changing the position of the light emitting unit  70 , that is, a light emitting focus of the light emitting unit  70 . In other words, the light emitting unit  70  is instantaneously moved rearward, according to Fleming&#39;s left-hand law, by the magnetic field of the coil  30  and the magnet  60 , when a dimmer switch is operated. At this time, the focus of the light emitting unit  70  precisely corresponds with the focus of the reflecting mirror.  
         [0043]    When the dimmer switch is operated again to change from a high-beam mode to a low-beam mode, an electric current supplied to the coil  30  is immediately shut off. At this time, the compression spring  40  interposed between the holding step  51  of the operating member  50  and the coil  30  is returned to its original position by a restoring force of the compression spring  40 .  
         [0044]    The operation of the headlight according to the present invention will be described in detail, with reference to FIGS. 3 and 4.  
         [0045]    Referring to FIGS. 3A and 4A, the compression spring  40  is interposed between the operating member  50 , which is provided in the space  11  of the housing  10  and axially holds the inside portion of the light emitting unit  70 , and the coil  30 , which is provided in the space  11  of the housing  10  at a position adjacent to the rear end of the housing  10 . When one desires to irradiate a high-beam in such a state, the dimmer switch is turned on. At this time, an electric current is applied to the coil  30 , so a magnetic field is produced in the coil  30 . Due to the magnetic field, the magnet  60  mounted to the operating member  50  moves into an axial guide hole  31  of the coil  30 . Simultaneously, the light emitting unit  70  is moved into the space  11  of the housing  10  along with the operating member  50 , so the focus of the light emitting unit  70  is formed as shown in FIG. 3B and 4B. That is, the focus of the light emitting unit  70  coincides with the focus of the reflecting mirror.  
         [0046]    Such an operational principle follows Fleming&#39;s left-hand law, which defines the relationship between the magnitude and direction of a force, the direction of an electric current and a magnetic field. That is, when an electric current is applied to the coil  30  which is placed between two electrodes of a permanent magnet, a force for moving the coil  30  in a given direction is generated. According to such a principle, the operating member  50  holding the light emitting unit  70  moves toward the coil  30  via a magnetic force of the magnet  60 .  
         [0047]    Meanwhile, when the dimmer switch is operated again to irradiate a low-beam, the electric current supplied to the coil  30  is shut off, and the operating member  50  holding the light emitting unit  70  is returned to its original position by the restoring force of the compression spring  40 . In the headlight of the present invention, a force is generated between the coil  30  and the magnet  60  according to Fleming&#39;s left hand law when the dimmer switch is operated to irradiate a high-beam. Thus, the operating member  50  holding the light emitting unit  70  is moved toward the coil  30 , which is fixedly provided in the housing  10  at a position adjacent to the rear end of the housing  10 , by a magnetic force of the magnet  60  which is fixed to the operating member  50 . The headlight of the present invention allows the focus of the light emitting unit  70  held by the operating member  50  to be easily changed, thus being very simple to selectively irradiate a high-beam or a low-beam. Although the headlight of the present invention is operated by electrically moving a single light emitting unit  70 , the same operational effect as a conventional headlight with two light emitting units is achieved. Further, the headlight of the present invention allows the merits of the gas-discharge lamp to be maximally utilized.  
         [0048]    In the meantime, it is preferable that a horizontal distance of movement of the operating member  50  is approx. 5˜7 mm. Because, according to FMVSS  108 , an US automobile standard, a distance between two filaments is 6.3 mm when two filaments are provided in a front/rear direction. Of course, the horizontal distance of movement of the operating member  50  is not limited to 5˜7 mm, but an appropriate adjustment is possible for taking accuracies of different components into account or obtaining an optimal performance.  
         [0049]    Another embodiment of the present invention will be described with reference to FIGS.  5 ˜ 8 .  
         [0050]    The embodiment is operative in a principle the same with the foregoing embodiment, except the operating member is operative in a vertical direction while the operating member of the foregoing embodiment is operative in the horizontal direction.  
         [0051]    A control rib  13  is provided on an inside wall of the housing  10  to limit a vertical moving range of an operating member  50   a.    
         [0052]    Two hinge slots  14  are axially formed at opposite positions of an edge of a mouth of the housing  10  such that two latitudinal hinge shafts  55 , which are provided on a sidewall of the support part  53 , are seated into the hinge slots  14 . A mounting boss  12  is provided at a position of an upper portion of the housing  10 . The coil  30  is inserted into the mounting boss  12  such that the magnet  60  is moved into an axial guide hole  31  which is formed through a center of the coil  30 .  
         [0053]    In the meantime, the operating member  50   a  of the embodiment includes a support part  53  fitted to one side of the light emitting unit  70 , and a support bar  57  fitted to the other side of the support part  53 . The support part  53  has hinge shafts  55  for inserting into hinge slots  14  in the housing  10 , and a magnet  60  is fitted on an upper surface of a fore end of the support bar  57 .  
         [0054]    When an electric current is applied to the coil  30  which is inserted into the mounting boss  12 , the magnet  60  is inserted into the axial guide hole  31  of the coil  30 . The magnet  60  is moved along with the operating member  50   a . The operating member  50   a  includes the support part  53  and the support bar  57 . A light emitting unit  70  is mounted to a center of the support part  53 . The latitudinal hinge shafts  55  are provided on the sidewall of the support part  53 , and seated into the hinge slots  14  of the housing  10 . The support bar  51  is eccentrically mounted at an end thereof to a rear portion of the support part  53 .  
         [0055]    An annular gap S is defined between the inner circumferential surface of the housing  10  provided with the hinge slot  14  and the outer circumferential surface of the support part  53  of the operating member  50 , so that the gap changes a focus of the light emitting unit  70 , thus selectively irradiating a low beam or a high beam. Preferably, a width of the gap S is set to 1-3 mm. Because, according to FMVSS  108 , an US automobile standard, a distance between two filaments is 2.3 mm when two filaments are provided in an up/down direction. Such a gap S allows the operating member  50   a  to pivot on the hinge shafts  55  in a seesaw manner. When it is required to change from a low-beam mode to a high-beam mode, a bulb, which is provided along a center of the light emitting unit  70 , is moved by about 2.3 mm during the seesaw action of the operating member  50   a . Of course, the vertical distance of movement of the operating member  50   a  is not limited to 1˜3 mm, but an appropriate adjustment is possible for taking accuracies of different components into account or obtaining an optimal performance.  
         [0056]    According to the present invention, a position of the light emitting unit  70 , that is, a focus of the light emitting unit  70  is changed by attraction between the coil  30  inserted into the mounting boss  12  of the housing  10  and the magnet  60  mounted on the support bar  57  of the operating member  50   a  due to the magnetic field of the coil  30  and the magnet  60 . That is, when the dimmer switch is operated to change the position of the light emitting unit  70 , the operating member  50   a  holding the light emitting unit  70  is rapidly moved to the coil  30  according to Fleming&#39;s left-hand law by the magnetic field of the coil  30  and the magnet  60 , so that the focus of the light emitting unit  70  precisely corresponds to a focus of the reflecting mirror.  
         [0057]    When the dimmer switch is operated again to change from a high-beam mode to a low-beam mode, the electric current applied to the coil  30  is immediately shut off. At this time, the operating member  50   a  is downwardly moved by a restoring force of the spring  40  which is fitted over the magnet  60  to be elastically interposed between the support bar  57  and the coil  30 , thus rapidly returning to an original state. In the embodiment of the present invention, the spring  40  comprises a compression coil spring. Alternatively, the spring  40  may comprise a tension spring to achieve the same operational effect.  
         [0058]    The operation of the headlight according to the present invention will be described in detail with reference to FIGS. 7 and 9.  
         [0059]    Referring to FIGS. 7A and 8A, a focus of the light emitting unit  70  is changed, when the operating member  50   a  holding the light emitting unit  70  pivots on the hinge shafts  55  in a seesaw manner. In normal times, the spring  40  which is fitted over the magnet  60  to be elastically interposed between the support bar  57  and the coil  30 , biases the support bar  57  downward by a spring force, so a low-beam mode is normally operated.  
         [0060]    When one desires to operate a high-beam mode in such a state, the dimmer switch is turned on. At this time, an electric current is applied to the coil  30 , so a magnetic field is formed in the coil  30 . Due to the magnetic field, the magnet  60  mounted on the rear portion of the support bar  57  is inserted into the guide hole  31  of the coil  30  while the support part  53  holding the light emitting unit  70  is downwardly moved, so the focus of the light emitting unit  70  is moved as shown in FIG. 7 b  and  8 B. That is, when a current is applied to the coil  30 , the support bar  57  moves up around the hinge shafts on the support part  53 , and the light emitting unit  70  moves down.  
         [0061]    Such an operating principle follows Fleming&#39;s left-hand law, which defines the relationship between the magnitude and direction of a force, the direction of an electric current and a magnetic field. That is, when an electric current is applied to the coil  30  which is placed between two electrodes of a permanent magnet, a force for moving the coil  30  in a given direction is generated. According to such a principle, the operating member  50   a  holding the light emitting unit  70  easily moves toward the coil  30  via a magnetic force of the magnet  60 .  
         [0062]    Meanwhile, when the dimmer switch is operated again, the electric current applied to the coil  30  is shut off. At this time, the operating member  50   a  holding the light emitting unit  70  is rapidly returned to its original state by a restoring force of the spring  40 , so the light emitting unit  70  is changed to a low-beam mode. A force generated between the coil  30  and the magnet  60  follows Fleming&#39;s left-hand law.  
         [0063]    In the headlight of the present invention, according to Fleming&#39;s left-hand law, the magnet  60  of the operating member  50   a  which is received in the housing  10  is moved to the coil  30  which is inserted into the mounting boss  12  by a magnetic force of the magnet  60  of the operating member  50   a  holding the light emitting unit  70 . The headlight of the present invention allows the focus of the light emitting unit  70  to be easily changed, thus being very simple to selectively irradiate a high beam or a low-beam. Although the headlight of the present invention is operated by electrically moving a single light emitting unit  70 , the same operational effect as a conventional headlight with two light emitting units is achieved. Further, the headlight of the present invention allows the merits of the gas-discharge lamp to be maximally utilized.  
         [0064]    In the meantime, though the embodiment describes the hinge shafts  55  at left/right sides of the support part of the operating member  55   a  for the seesaw movement of the operating member  55   a , the present invention does not limit to this. That is, the hinge shafts  55  may be formed in an up/down direction for moving the operating member  55   a  in up/down direction wholly, to control a position of a focal point of the light emitting unit  70 .  
         [0065]    As described above, the present invention provides a vehicle headlight which is simply operated according to Fleming&#39;s left-hand law and selectively irradiates a high beam so as to provide long-range illumination when driving the vehicle at night or a low beam so as not to obstruct the vision of oncoming drivers, using a single light emitting unit.  
         [0066]    Further, the present invention provides a vehicle headlight which is easily replaced with a conventional headlight using a halogen lamp without changing the structure of an existing vehicle, and which allows gas-discharge lamps which are now used only in luxury cars to be widely used.  
         [0067]    In the meantime, though the foregoing embodiments show an operating member  50  or  50   a  fitted with a magnet  60 , and a housing  10  fitted with a coil  30 , the present invention is not limited to this. That is, the coil  30  may be fitted to the operating member  50  or  50   a , and the magnet  60  may be fitted to the housing  10 .  
         [0068]    Moreover, elastic means, i.e., a spring is fitted between the magnet  60  and the coil  30 , so that the light emitting unit  70  positioned in a low beam state by the elastic force of the spring is shifted to a high beam position as a current is applied to the coil  30 , which causes the magnet  60  to overcome the elastic force of the spring to move toward the coil direction  30 . However, the present invention is not limited to this, but, without using the spring  40 , a direction of the current to the coil  30  may be changed selectively, to achieve the same object.  
         [0069]    Furthermore, though the embodiments describe that the light emitting unit is a gas discharge lamp, the present invention is not limited to this, but a halogen lamp may be used. Also, though the reflective mirror is a parabolic mirror, the present invention is not limited to this.  
         [0070]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.