Total Stopping Distance Indicator

Abstract

Disclosed is a total stopping distance indicator including a speed responsive device that controls an indicator such as a variable light source. The light source projects a variable beam of light in front of an equipped vehicle. In one preferred embodiment the intensity of the light beam is variable and in another preferred embodiment the direction of the light beam is variable. In either embodiment, the components of the system are adjusted so that the light just reaches the fringe of the area required for a safe stop at any given speed.

Description

BACKGROUND OF THE INVENTION

This invention relates to motor vehicle speed responsive devices and, more particularly, to those devices that indicate total stopping distance required at any given vehicle speed.

As our highways have become more congested, the problem of drivers too closely following the vehicle in front of them has become more serious. Student drivers are taught that for each 10 miles per hour of speed they should maintain one car length of separation between their vehicle and the preceding vehicle. This rule is often ignored and, even when followed, it sometimes proves inadequate. That is so because the rule does not take into consideration the possibility that the first car in a series may stop by panic breaking or by impact. Consequently it is desirable that the separation between vehicles be greater than one car length for each 10 miles per hour of vehicle speed, particularly at high speeds. In fact, it has been found that the desired separation between vehicles in the range of speed commonly driven increases with speed in approximately an exponential fashion.

The exponential relationship between speed and vehicle separation has prevented the adoption of a simple general rule to permit drivers to easily convert vehicle speed to desired vehicle separations. Consequently modified speedometer type devices were devised to apprise drivers of desired vehicle separation. See, for example, U.S. Pat. No. 2,845,721 issued to Adler.

A problem encountered in the utilization of apparatus such as that disclosed by Adler is that the vehicle separations indicated for medium and high speed driving are so great that most drivers cannot properly judge them with an acceptable degree of accuracy. Thus the desired improvement in vehicle safety was not fully achieved.

Finally, apparatus such as Doppler or radar systems were developed to provide an alarm when the separation between vehicles fell below the desired minimum. However, due to the high cost of these systems, they have not been widely adopted.

The object of this invention, therefore, is to provide a relatively low cost vehicle separation indicator that will accurately apprise a vehicle operator when the separation between his vehicle and the preceding vehicle has fallen below a minimum desired separation.

SUMMARY OF THE INVENTION

This invention is characterized by a motor vehicle stopping distance indicator including a speed responsive device that controls an indicator such as a variable light source which projects a beam of light in front of the vehicle. Two variable light source embodiments are disclosed. In one of the embodiments the orientation of the light source is controlled by the speed responsive device so that the direction of the beam varies with speed. At lower speeds the light source is directed at a relatively sharp downward angle and thus strikes the road surface relatively near the vehicle. As speed increases, the beam is projected farther from the vehicle. In the second embodiment the intensity of the light source is variable and the intensity becomes greater as the vehicle speed becomes greater. In each embodiment the beam of light is indicative of the safe vehicle stopping distance inasmuch as the vehicle will require the entire illuminated space to stop. Furthermore, the beam indicates safe following distance inasmuch as when the beam is illuminating the vehicle preceding the equipped vehicle the vehicle separation is inadequate. It is realized that the subject device loses some of its effectiveness as a following distance indicator on curved and hilly roads where the beam may be directed away from the preceding vehicle from time to time but it is felt that that function is most needed on flat straight roads where persons have a tendency to speed and follow too closely. In addition, the stopping distance indication has great value on curved roads because trees near the road may be illuminated if the vehicle is moving at high speed. Such illumination of trees should serve as a warning to slow down on curves.

Preferably, the light source includes a strobe light source to provide a very narrow high intensity beam and thus improve beam visibility during daylight hours. Furthermore, it is preferable that the beam be colored, as for example, red. If a high intensity colored beam is provided, it can be distinguished from light emanating from vehicle headlights during evening hours.

Another embodiment disclosed includes a speed responsive device including a movable indicator portion for indicating the speed of the vehicle. Also included is a stopping footage indicator with a scale bearing indicia indicative of the number of feet required to stop. The footage scale is read in conjunction with a stopping footage indicator portion of the movable indicator. Finally, there is included a following distance indicator including a following distance scale calibrated in units of car lengths for indicating, in conjunction with a following distance portion of the movable indicator, safe following distances. This embodiment continually advises drivers of the speed of their vehicle, the number of feet required to stop the vehicle at a given speed and a safe following distance in terms of car lengths. Consequently, the driver is constantly aware of whether or not he is driving safely and within the posted speed limits.

DESCRIPTION OF THE DRAWINGS

These and other features and objects of the present invention will become more apparent upon a perusal of the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 shows a motor vehicle equipped with the subject apparatus;

FIG. 2 is a block diagram of one preferred embodiment of the subject indicator apparatus;

FIG. 3 is a sectional view of the variable light source utilized in a second preferred embodiment of the indicator apparatus;

FIG. 4 is a diagram of another embodiment of the subject invention; and

FIG. 5 is another diagram of the device depicted in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1 there is an elevation view of an automobile 21 including a motor vehicle stopping distance indicator 22 with a variable light source 23 that projects a beam of light 24 and is mounted near the vehicle front bumper 25.

Referring now to FIG. 2 there is a block diagram of one embodiment of a vehicle stopping distance indicator 22a. A speedometer cable 26 is coupled to the equipped vehicle's speedometer 27 in the conventional manner. The speedometer 27, in response to vehicle speed, sets a potentiometer 28 via a coupling 29. The output of the potentiometer is coupled by a line 31 to a variable intensity light source 23a that includes a variable intensity strobe that preferably produces a very narrow beam 24a of red, or other colored, light. It will be appreciated that as the speed sensed by the speedometer 27 increases the intensity of the beam 24a increases.

Referring now to FIG. 3 there is shown a portion of a second preferred embodiment 22b of a motor vehicle stopping distance indicator. A variable light source 23b is shown in section. A speedometer like the speedometer 27 is utilized and the speedometer output is coupled by a line 29b to a servo mechanism 32 that includes an output shaft 30. The angular position of the output shaft 30 is dependent on the signal on the line 29b and thus on the vehicle speed. A small strobe 33 that produces a red light is mounted in a reflector 34 that is secured to the light source housing at a pivot point 35. A stud 36 projects from the rear of the reflector 34 and interacts with a groove 37 in a cam drum 38 that is coupled to the shaft 30. Consequently, the angular position of the cam 38 and thus the position of the reflector 34 is dependent on the signal on the line 29b. A line 39 couples a strobe power source 41 to the strobe 33. The combined effects of the strobe 33 and the reflector 34 produce a narrow, well-focused beam of red light 24b that passes through an opening in the vehicle front bumper 25. The variable position light source 23b is mounted on a mounting plate 42 at a level of the vehicle front bumper 25. The various components of the light source 23b are selected so that the light beam 24b illuminates an area farther from the vehicle as the vehicle speed increases.

During operation of either the embodiment 22a or 22b, the vehicle can safely be driven as long as the preceding vehicle is not illuminated by the beams of red light 24a or 24b. If the separation between the equipped vehicle 21 and the preceding vehicle falls to less than the desired minimum vehicle separation, the preceding vehicle will be illuminated by the beam 24a or 24b. It will be appreciated, of course, that the permissable vehicle separation is dependent on the vehicle speed which controls the intensity of the beam 24a or the angular position of the beam 24b.

It is considered advantageous that the speedometer 27 be calibrated with dual scales. Thus, the speedometer 27 can indicate both vehicle speed in miles per hour in the conventional fashion, and can indicate minimum vehicle separation or vehicle stopping distance in units of car lengths or feet, or both.

It is felt that an option of a less expensive variable light source can be utilized if it is to be functional only at night. For a night driving light source the beam does not have to be so powerful or well defined. However, the beam should still be colored so as to be distinguishable from the light emanating from automobile headlights. While night use only of the device does not provide complete protection, it is felt that use of a speedometer indicative of safe stopping distances, coupled with the indication of stopping distance provided by the light, will develop good driving habits while driving at night. If these good habits are carried over to day time driving, a desirable improvement in automobile safety will result.

Referring now to FIGS. 4 and 5 there is shown another embodiment of a motor vehicle stopping distance indicator 51 including a speed responsive device 52 with a scale 53 bearing indicia 54 indicative of vehicle speeds similar to a conventional speedometer. A mask portion 50 (shown only in FIG. 5) defines an aperture window 55 and a pointer 56. The entire mask and pointer moves in response to conventional apparatus to indicate vehicle speed in the conventional manner. Visible behind a lower stopping footage indicator portion 57 of the window 55 is a block containing indicia 58, specifically the numeral 132. The significance of the indicia 58 is that it would require the vehicle 132 feet to stop the speed of 40 miles per hour. An upper car length indicator portion 59 of the window 55 reveals a block containing indicia 61 indicative of the outline of an automobile with the numeral 8 therein. The significance of the indicia 61 is that the vehicle should maintain a separation of 8 car lengths between it and the preceding vehicle at a speed of 40 miles per hour. It will be appreciated that the indicia 58 is only part of a footage indicator scale and the indicia 61 is part of a car length indicator scale. Normally, however, all but what is within the window 55 is obscured by the mask 50 as shown in FIG. 5. The moving mask itself has been eliminated in FIG. 4 to clearly show the scales utilized in the device 51.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, other methods of preventing variable illumination can be used. It is to be understood, therefore, that the invention can be practiced otherwise than as specifically described.

Claims

What is claimed is:

1. A motor vehicle stopping distance indicator for mounting on motor vehicles and comprising:

speed responsive means for determining the speed of the vehicles; and

a stopping indicator comprising a variable light source means for projecting ahead of the vehicle a visible light beam having a variable length responsive to said speed responsive means so as to indicate the total safe stopping distance of the vehicle by making the length of the projected beam equal to the distance normally required to stop the vehicle under predetermined conditions.

2. An indicator according to claim 1 wherein said variable light source means comprises variable orientation means for projecting the beam of light in different directions with respect to the motor vehicle.

3. An indicator according to claim 2 wherein said variable light source means comprises strobe light source means.

4. An indicator according to claim 3 wherein said strobe light source means comprises red strobe light source means.

5. An indicator according to claim 2 comprising bumper level mounting means for mounting said variable light source means at bumper level.

6. An indicator according to claim 1 wherein said variable light source means comprises variable intensity light source means for projecting a beam of light of a variable intensity.

7. An indicator according to claim 6 wherein said variable light source means comprises strobe light source means.

8. An indicator according to claim 7 wherein said strobe light source means comprises red strobe light source means.

9. An indicator according to claim 1 wherein said speed responsive means comprises speedometer means.

10. An indicator according to claim 9 wherein said speed responsive means comprises indicia indicative of required stopping distances.