Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1997-02-19
2001-05-29
Sember, Thomas M. (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S530000, C362S532000, C362S465000, C362S467000
Reexamination Certificate
active
06238071
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general terms to motor vehicle headlights. More particularly, the invention is directed to headlights having a single light source, such as a lamp or light bulb, the headlight being adapted to produce, selectively, a dipped beam and a main beam.
BACKGROUND OF THE INVENTION
It is already known, in particular from French patent specification No. FR 1 461 607 A, to provide a headlight which has a single light source, in this case a monofilament lamp, which co-operates with a reflector which is adapted to tilt about a horizontal axis at right angles to its optical axis. In its downwardly tilted position, the dipped beam, i.e. the beam which is intended to prevent dazzling of the occupants of oncoming vehicles, is formed. The reflector is raised in order to obtain a main beam, or cruising beam, of longer range.
This particular known type of headlight is of a construction which is completely unsuitable for modern headlights, and in particular those which further include means for correcting the orientation of the beam both in elevation and azimuth, these correcting means being either manual or automatic.
It is also known, from German patent specification DE 4 418 733 A, to provide a headlight which is adapted to produce from a single light source (such as a filament or an arc), together with a single reflector, both of these two types of beam. In this connection, the reflector has a fixed portion and one or more moveable portions. The displacement of the moveable portions, by means of appropriate actuators, effects the change from one type of beam to the other.
However, this approach is disadvantageous, in that it greatly complicates the design and manufacture of the reflector, and in some cases it gives rise to losses of light, or optical faults, especially at the interfaces between the fixed and moveable portions of the reflector.
United Kingdom patent specification No. GB 2 192 449 A discloses a headlight in which the operation of changing from the dipped beam mode to the main beam mode is effected by tilting the reflector by means of two devices, each of which acts on one respecting bearing point, or support point, of the reflector. However, that particular arrangement is expensive, because it makes use of two control devices for changing the beam from the dipped mode to the main beam mode. In addition, these two control devices are entirely dedicated to the change from dipped to main beam, and no other device for correcting the orientation of the beam (for example any dynamic correction device) is provided in that headlight.
DISCUSSION OF THE INVENTION
The present invention aims to overcome the drawbacks of the state of the art, and to provide a headlight which, in a simple and inexpensive way, enables a single light source and a single reflector, forming one unit, to be used in order to produce two light beams having different functions, in particular the function of a dipped beam and that of a main beam.
Another object of the present invention is to provide an effective combination of a beam switching device, for changing the beam between its dipped and main beam modes, with other devices for correcting the beam, all in the same headlight.
According to the invention, a motor vehicle headlight comprising a single light source, a single reflector receiving the said light source, or lamp, the reflector being mounted on three bearing points constituting a tripod support for the reflector and disposed at the three apices of a triangle, together with controlled displacement means for selectively displacing in straight line movement at least one of the said bearing points, is characterised in that the displacement means comprise a single beam switching device for displacing one of the three bearing points into one of only two discrete positions, namely a first position corresponding to a dipped beam and a second position, raised with respect to the said first position and corresponding to a main beam.
The said beam switching device is preferably in vertical alignment with a fixed point.
According to a preferred feature of the invention, the headlight further includes, acting on a said bearing point which is aligned vertically with a fixed point, at least one device for correcting the orientation of the beam in elevation.
The said correcting device or devices preferably include, or consist of a manual device; in preferred embodiments, a said correcting device is a dynamic correcting device for correcting beam orientation as a function of variations in attitude of the vehicle.
According to another preferred feature of the invention, the said displacement, or beam switching, device is adapted to raise the beam and to offset the beam laterally away from the nearside verge of the road. This displacement or beam switching device is then preferably situated at the level of a bearing point opposed to a side of the triangle which is oblique with respect to the horizontal and with respect to the vertical.
In this last mentioned embodiment, according to a further preferred feature of the invention the headlight further includes a dynamic correcting device for correcting beam orientation as a function of variations in attitude of the vehicle, the said dynamic correcting device being arranged at the level of a said bearing point which is aligned vertically with the said bearing point opposed to the said oblique side of the triangle.
Another preferred feature of the said embodiment is that the headlight further includes at least one manual correcting device for effecting manual correction of the beam, the said manual correction device being situated at the level of a bearing point which is different from the said bearing point opposed to the oblique side of the triangle.
The inclination of the said oblique side of the triangle, with respect to the horizontal, is preferably made equal to the inclination of the direction of displacement of the beam with respect to the vertical.
In preferred embodiment of the invention, the ratio between the angle of the lateral offset of the beam away from the nearside verge, and the angle through which the beam is raised, both effected by the beam switching device, is of the order of 2:1.
According to yet another preferred feature, the headlight includes a reflector which is adapted to form by itself a wide dipped beam, and the lens of the headlight is smooth or has only a slight function of diverting light.
In some embodiments of the invention, the said controlled displacement means comprise the said beam switching device, the latter being motorised and adapted for effecting displacement of a bearing point, in that a motorised dynamic correcting device is provided for correcting beam orientation according to variations in attitude of the vehicle by acting on the same bearing point, and in that the said beam switching device and the said dynamic correcting device are driven by the same motor.
The said beam switching device may be selected from the group comprising electromagnets having two positions, blocked-torque motors, and stepping motors.
The headlight may further include means for effecting dynamic correction of the orientation of the reflector in response to variations in attitude of the vehicle, together with means for inactivating the said dynamic correcting means while a change of the beam orientation from its dipped mode to its main beam mode is being carried out.
Further aspects, features and advantages of the present invention will appear more clearly on a reading of the following detailed description of some preferred embodiments of the invention, which are given by way of non-limiting example only and with reference to the accompanying drawings.
REFERENCES:
patent: 4574334 (1986-03-01), Igura
patent: 4739223 (1988-04-01), Baba et al.
patent: 4916587 (1990-04-01), Hirose et al.
patent: 4954933 (1990-09-01), Wassen
patent: 5003436 (1991-03-01), Yamada et al.
patent: 5381313 (1995-01-01), Choji
patent: 5390088 (1995-02-01), Tsukada
patent: 5599085 (1997-02-01), Tabata et al.
patent: 5673993 (19
Morgan & Finnegan , LLP
Sember Thomas M.
Valeo Vision
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