ROAD VEHICLE LIGHTING SYSTEM IN WHICH SAME SHUTTER OBSCURES PHOTOCELL WHEN SYSTEM IS OPERATIVE AND WHEN IT IS NOT ENERGIZED

• US 3,663,819 A
• Filed: 07/15/1970
• Issued: 05/16/1972
• Est. Priority Date: 07/23/1969
• Status: Expired due to Term

• Current Assignee: Harris Vernon Hicks, Roger William Nolan
• Original Assignee: Harris Vernon Hicks, Roger William Nolan
• Inventors: Hicks, Harris Vernon, Nolan, Roger William
• Primary Examiner(s): Borchelt, Archie R.
• Assistant Examiner(s): Grigsby, T. N.
• Application Number:
  US05/055,018
• Time in Patent Office: 671 Days
• Field of Search: 250/214D,201 315/82 240/46.05
• US Class Current: 250/201.1
• CPC Class Codes: B60Q 1/0023 the element being a sensor, e.g. distance sensor, camera
• CPC Class Codes: B60Q 1/1423 Automatic dimming circuits, i.e. switching between high beam and low beam due to change of ambient light or light level in road traffic
• CPC Class Codes: B60Q 2300/42 oncoming vehicle

Abstract

A lighting system for a road vehicle has the projector for producing a beam of light illuminating the road in front of the vehicle and a receiver with a photocell for receiving light from an oncoming vehicle. There is a first shutter movable to progressively cut off the projected beam, and a second shutter movable to progressively mask the photocell from light from an oncoming vehicle, so that the system achieves a condition wherein sufficient of the projected beam is cut off to avoid dazzling the driver of the oncoming vehicle. The second shutter is returned to a rest position, wherein the photocell is masked, when the projector is not energized, and means is provided for moving the second shutter, when the projector is energized to an inoperative position wherein light can fall on the photocell. This prevents saturation of the photocell during daylight hours.

Claims

1. A lighting system for a road vehicle including a projector for producing a beam of light illuminating the road in front of the vehicle utilizing the system, a receiver, including a photo cell, for receiving light from an oncoming vehicle, a first shutter movable to progressively cut off the projected beam, a second shutter movable, from a datum position in which light from an oncoming vehicle can fall on said photo cell, to progressively mask the photo cell from light from an oncoming vehicle, means operable in response to stimulation of the photo cell by light from an oncoming vehicle for moving the first and second shutters so that the system achieves a condition wherein sufficient of the projected beam is cut off to avoid dazzling the driver of the oncoming vehicle, and in which said second shutter is returned to a rest position, wherein the photo cell is masked, when the projector is not energized, and means is provided for moving said second shutter when the projector is energized, to said datum position.

2. A system as claimed in claim 1 in which the second shutter is moved to said rest position by gravity.

3. A system as claimed in claim 1 in which the second shutter is moved to said rest position by a spring.

4. A system as claimed in claim 2 in which the second shutter is moved from its rest position to its datum position by a control circuit which is energized when the projector is energized, the photocell acting in response to light from an oncoming vehicle to cause the control circuit to effect positive movement of the first shutter to a position in which sufficient of the projected beam is cut off.

5. A system as claimed in claim 4 in which the shutters are carried by a spool mounted for sliding movement in the magnetic field of a permanent magnet and carrying a winding, the current flow through which is controlled by the control circuit.

6. A system as claimed in claim 5 in which the winding is tapped along its length, one part of the winding being permanently energized in use to move the spool to a position corresponding to the inoperative position of the second shutter, and the other part of the winding acting to move the spool in the opposite direction, current flow in said other part of the winding being controlled by the photocell.

7. A system as claimed in claim 5 in which the control circuit includes a bridge network the output from which is applied to said winding, the bridge network passing current through the winding in one direction when the photocell is not illuminated to move the spool to a position corresponding to the inoperative position of the second shutter, and passing current through the winding in the opposite direction when the photocell is illuminated.

8. A lighting system for a road vehicle, comprising a projector for producing a beam of light illuminating the road in front of the vehicle utilizing the system, a receiver including a photo cell for receiving light from an oncoming vehicle, first and second interconnected shutters, a spring urging said first and second shutters to a rest position in which said first shutter cuts off the projected beam, and said second shutter masks the photo cell, a control circuit which is energized when said projector is energized, said control circuit when energized moving said shutters to a datum position in which said first shutter no longer cuts off the projected beam, and the second shutter allows light from an oncoming vehicle to fall on the photo cell, and means coupling the control circuit with said photo cell whereby said photo cell acts in response to light from an oncoming vehicle to decrease the output of the control circuit so that the shutTers are moved by said spring to a position wherein sufficient of the projected beam is cut off by said first shutter to avoid dazzling the driver of an oncoming vehicle.