FIELD OF THE INVENTION

The invention relates to a device for increased road safety and more particularly a warning device for motor vehicles, the object of which is to prevent or reduce traffic accidents by the 5 driver's attention being drawn to his unintentionally crossing the centre line of the roadway and on the way into the oncoming traffic lane, or his being on the way over the edge line driving off the road. The device also warns drivers attempting to overtake or to change their driving direction without flashing

10 the blinkers, and functions as an orientational aid in a dense fog and in parking on marked parking slots.

It is a serious and a well known problem with all traffic accidents which occur for various reasons and which tend to increase with the increased traffic intensity. A kind of

15 accident that occurs too often is when a driver of a motor vehicle dozes off or even falls asleep at the wheel and crosses the road centre line and drives into the oncoming traffic lane, or drives off the road to the right, in both cases too often resulting in disastrous consequensies.

20 A further, typical traffic problem is drivers who neglect to flash the blinkers when overtaking or when turning left or right, which will often cause serious accidents or incidents.

TECHNICAL BACKGROUND * 25 In the solutions known so far only daylight or lamplight has been used. This has a disadvantage in that scattered light "* and reflections from visible light may give false indications.

Another disadvantage is that the known device requires a compensation for the light receiver with regard to the ambient 30 varying light conditions.

SUMMARY OF THE INVENTION

In the present invention said drawbacks are avoided by using pulsed infrared (IR) light. Further advantages of IR light is a low power consumption, a large vibration endurance, a long life of the IR diodes compared with light bulbs. The system admits the possibility of a higher mounting height from the roadway, without jeopardizing the function.

Yet another advantage is that upon activation of the direction indicator (blinkers) the function of the device according to the invention may be blocked in order to avoid undue warning signals when the white marking lines on the roadway are intentionally crossed, such as in change of lanes, overtakings, or right and left turns, respectively.

The object of the invention is to prevent or mitigate the effect of personal injuries or vehicle damage, which often occur when a driver dozes off or falls asleep at the wheel and as a consequence unintentionally leaves the correct lane, and when a driver neglects to flash the blinkers when overtaking and in other changes of lanes or driving directions, which, unfortunately, often also causes serious accidents and incidents. Said object is achieved by the characteristics defined in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described below with reference to the attached figures, in which

Fig. 1 discloses a motor vehicle driving on a roadway, with an example of the road centre line and the edge lines,

Fig. 2 discloses a motor car, viewed from the front, having a detector A, an electronic unit B and buzzers C according to the invention mounted,

Fig. 3 discloses a front of a motor car, viewed from the right-hand side having a detector A mounted,

Fig. 4 discloses a complete detector unit A according to the invention, and

Fig. 5 discloses a block diagram of the warning device according to the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

The present invention relates to a warning device for motor vehicles. The device will sense when a road marking Line painted on the roadway is unintentionally crossed and will then issue a warning signal to the driver. In Fig. 1 the warning device according to the invention is shown mounted on a motor vehicle D driving in the direction J on a typical roadway having road marking lines of various kinds. In the figure there are shown, by way of example, short edge lines E, a side solid line F, a long centre line G and a centre solid line H. The device comprises a detector A, an electronic unit B and buzzers C, described more detailed below.

Figs. 2 and 3 give examples of the installation of the invention in a motor car. The device is also suitable to be mounted in lorries, buses, trucks, and other vehicles.

The warning device is used according to the following. The detector unit A is provided for detecting road lines painted on the roadway. When the unit A is straight above a road marking line a signal will be delivered to the electronic unit B, which unit will activate a device for issuing an acoustic (buzzers C) and/or a visual signal to the driver. Tests have shown that in a normal driving on main roads the duration of the warning signal should be 3-5 seconds. The electronic unit thus provides for the warning signal to remain during an appropriate period of time after the road marking line has been crossed and the detector unit A no Longer remains over the line. This is because the driver should have time for perceiving the signal and for responding.

The duration of the signal is adjustable by a control, suitably on the dashboard. In driving in a dense fog and in parking, the warning signal, for instance, should sound (light) only the period of time during which either of the detectors A is straight above a white marking line to help the driver orientate himself more exactly. The buzzers C are constructed so as to issue a signal with distinctly separable frequencies for the left-hand and the right-hand side, so that the driver's attention will be

instantly drawn to which direction the incorrect change of course has been made.

There are occasions when intentionally you want to cross the marking lines, e.g. in change of lanes, at turns, at crossings, and so on. Then, it is not desired to be bothered by warning signals, so there must be a possibility of disactivating them. According to the invention the warning device may be permanently disactivated by means of a main switch, but there are various possibilities of a temporary disactivation as well. Since marking lines are often crossed at turns it is suitable to arrange an interruption in connection with the direction indicator. This would also contribute constructively to an increased use of the indicators. According to the invention the warning device will be disactivated when you begin to signal and remains disactivated for a certain period of time after the indicator has been brought back to neutral. The time period during which the warning device is disactivated may be fixed, e.g. 15 seconds, or variable by means of a control.

According to the invention the warning device may also be ^' temporarily disactivated by a special control for this purpose. This control will be used when a marking line is to be crossed without signalling for a left or a right turn. It may suitably be arranged in form of a nonlocking control near the indicator control. In other respects, the disactivation will be effected in the same way as above.

The technical construction of the warning device is described more closely below with reference to Figs. 4 and 5.

The detector unit A in Fig. 4 comprises an IR transmitting diode 1, a reflector 2, and a holder of Plexiglass or the Like 3. Transmitting diode 1, reflector 2 and holder 3 are joined and vertically adjustable within a chromium-plated metal tube 5 according to the arrow 6. Receiving diode 12 and holder 13 within tube 15 have the same possibility of adjusting according to the arrow 16. The possibility of adjusting admits adaptation of sensitivity and range. To prevent soiling of the unit the transmitting and the receiving diodes are preferably mounted as high as possible within the metal tubes 5, 15. The mouths of the

metal tubes may as well be provided with transparent protective discs 9, 19.

A detector unit A is preferably arranged in either of the front bumper corners of the vehicle, as shown in Fig. 2. The distance from the units to the roadway is adapted with respect to the type of vehicle. Appropriate distances are in the range of 15 to 40 cm, preferably 25 to 30 cm.

Transmitting part S of Fig. 5 emits a pulsed signal voltage with the frequency of about 10 kHz and is connected via a screened cable 4 through a sealing 7 to the detectors A and the IR transmitting diode 1 of Fig. 4 being therein. This diode emits a pulsed IR light which illuminates part of the roadway 11. Upon touching of a white marking line 10 the pulsed IR light 8 is reflected back to the detector A and the IR receiving diode 12 being therein, the sensitivity range of which is adapted to the pulsed IR light 18 of Fig. 4. The receiving diode 12 is via a cable 14 through a sealing 17 connected to the left L or the right R part of the receiving unit M of Fig. 5. The receiving part M delivers a signal voltage to the buzzer C of fig 5 of the side which corresponds to the IR diode that has activated the receiver. The receiving parts M. and M _R are provided with a ganged switch for choosing an appropriate duration of the warning signal.

A breaker N symbolizes the temporary disactivation of the device, as described above. In practice, the breaker may be arranged in many different ways, preferably as an electronic control of the effect of the transmitting part S. The breaker is connected to the control for the direction indicator and for temporarily disactivating the device. The breaker 0 of Fig. 5 relates to a main switch for switching on and off the device.

The transmitting part S is provided with a potentiometer for controlling the signal voltage level to the IR transmitting diodes 1 of Fig. 4 for adapting the range and sensitivity of the device in a great deviation in the reflective power of the white marking lines.