Warning light for emergency vehicles

A warning light for emergency vehicles for which light sources project parallel light beams along predetermined paths with a rotatable reflector having opposite reflective surfaces for directing the parallel light beams to the front and alternately to the rear of the vehicle, and a stationary reflector for periodically directing at least one of the light beams in a predetermined direction.

The present invention relates to a warning light for emergency vehicles and 
particularly relates to a warning light system providing flashing lights 
and points of illumination visible from the front, rear, and sides of the 
vehicle as well as high intensity narrow dispersion flashing points of 
illumination for long range visibility. 
Many and various types of warning lights for emergency vehicles have been 
proposed and constructed in the past. One of the most common lights of 
this type is comprised of a bulb having a parabolic reflector mounted for 
rotation about the bulb whereby a flashing or blinking effect is provided. 
An example of this type of warning light is disclosed in U.S. Pat. No. 
2,814,029. Another example of a warning light for emergency vehicles is 
disclosed in U.S. Pat. No. 3,404,371 in which a pair of oppositely 
directed light sources on each side of a light bar alternately project 
their beams against a parabolic reflector to provide flashing lights of 
increased intensity to one side of the light bar. Strobe lights have also 
been utilized as warning lights in emergency vehicles. Various 
disadvantages, however, are associated with these and other known warning 
lights for emergency vehicles. For example, when rotating light sources 
are utilized, electrical brushes and elaborate mountings are required. 
These installations are thus expensive to manufacture and subject to wear 
necessitating periodic maintenance and replacement. With respect to strobe 
lights, significant electronic circuitry is required thus increasing the 
cost and expense of utilizing strobe lights in emergency vehicles. 
Furthermore, the foregoing and other warning lights for emergency 
vehicles. known to applicant generally do not provide optimum visibility 
for example, both long and short range warning. That is, many such prior 
devices are arranged to provide flashing lights of only adequate intensity 
and/or high dispersion whereby only limited range warning is provided. 
Visible warning at extreme distances is a desirable feature of a safe 
adequate warning system but can be very often annoying at close distances 
when utilized in a warning light of the type herein considered. 
The present invention provides a warning light for emergency vehicles which 
minimizes and/or eliminates many of the foregoing and other problems 
associated with prior warning lights for emergency vehicles and provides a 
novel and improved warning light for emergency vehicles having various 
advantages in construction, operation and result in comparison with such 
prior warning lights. Particularly, the present invention provides a 
warning light for emergency vehicles characterized by the provision of 
both long and short range flashing points of illumination all emanating 
from like light sources. That is, in accordance with the present invention 
a plurality of blinking or flashing points of illumination are provided 
having the intensity and angular dispersion necessary to provide adequate 
warning and visibility at relatively short ranges. Conjunctively, the 
warning light hereof also provides long range, directionally controlled, 
flashing points of illumination to provide early visible warning at 
extreme distances. A feature of the present invention resides in the 
provision of three blinking points of illumination from each set of two 
light sources as amplified below. Particularly, the present invention 
provides a light bar for mounting on the roof of an emergency vehicle. The 
light bar includes a pair of sealed beam light sources on each side of the 
center line of the light bar and arranged to project a pair of parallel 
light beams laterally outwardly from the corresponding side of the 
vehicle. On each side of the light bar and in the path of the parallel 
directed light beams is provided a planar reflector having a pair of 
reflecting surfaces on each of its opposite sides. Each reflector is 
mounted on the light bar for rotation about a vertical axis. Upon rotation 
of the planar reflectors, a pair of flashing points of illumination are 
alternately visible from the front and rear sides of the vehicle and from 
each side of the light bar. 
Further, the axis of rotation of each reflector lies between the parallel 
light beams emanating from the side-by-side light sources. Consequently, 
during the rotary excursion of each reflector, it will obtain a position 
parallel to and between the parallel light beams emanating from the light 
sources whereby both light beams will pass the reflector. To provide a 
high intensity flashing point of illumination for long range visibility on 
each side of the light bar, a reflector is mounted on the outboard portion 
of the light bar at each of its opposite ends and in the path of one of 
the light beams emanating from the two light sources on the corresponding 
side of the vehicle. Each reflector is arranged to reflect the light beam 
in a direction parallel to the direction of movement of the vehicle. It 
will be appreciated that the rotating reflector interposed between the 
fixed reflector and the light source on each side of the light bar creates 
an on/off or shuttering effect with respect to the light beams reflected 
from the concave reflectors. This shuttering effect provides a blinking or 
flashing point of illumination on each side of the light bar visible from 
either the front or rear of the vehicle depending upon the selected 
orientation of the reflector. Also, the outer reflectors provide in 
conjunction with this shuttering action flashing points of illumination in 
the selected direction of particularly high intensity and narrow 
dispersion thus providing a visible warning at extreme distances. Each 
outer reflector may have a planar or concave reflecting surface. 
The high intensity of the outboard flashing points of illumination is 
believed a result of the abrupt increase and decrease in light intensity 
and the square waveform (with consequent long peak dwell) of the energy 
pulse of the light beams effected by rotation of the reflectors disposed 
between the outboard reflectors and the light sources, the rotating 
deflectors interacting with the outboard reflectors to create the on/off 
shuttering effect. The outboard deflectors may also be rotated or indexed 
such that the high intensity narrow dispersion light beams reflected from 
the light sources may be directed in either a forward or rearward 
direction relative to the vehicle which makes this warning light 
particularly useful at accident sites on high speed highways. It will also 
be appreciated that a single flashing light is visible from each side of 
the vehicle by the interaction of the rotary reflector with the other of 
the light beams emanating from the pair of light sources and not directed 
to the outboard reflector. 
For each set of two light sources, the foregoing arrangement provides (a) 
two flashing points of intense illumination having angular dispersion 
comparable to that created by existing rotating beacons visible from the 
front and rear of the vehicle, (b) a flashing point of illumination 
providing a reflected light beam of high intensity and narrow dispersion 
visible selectively from the front or rear of the vehicle, and (c) a 
flashing light visible from the corresponding side of the vehicle. 
Consequently, when two sets of two light sources each are utilized, six 
flashing points of illumination are arrayed across the light bar and 
visible from either the front or rear of the vehicle depending upon the 
selected orientation of the outbard reflectors. Four flashing points of 
illumination are always visible from each of the front and rear sides of 
the light bar. Additionally, a flashing light is visible from both sides 
of the vehicle. Thus, a highly efficient warning light is provided visible 
from the front, rear and sides of the vehicle and which provides effective 
long as well as short range warning from a greater number of points of 
illumination than light sources. 
Accordingly, it is a primary object of the present invention to provide a 
novel and improved warning light for emergency vehicles. 
It is another object of the present invention to provide a novel and 
improved warning light for emergency vehicles characterized by discrete 
flashing points of illumination visible at both long and short ranges. 
It is still another object of the present invention to provide a novel and 
improved warning light for emergency vehicles wherein optimum use of a 
predetermined number of available light sources is afforded by providing 
flashing points of illumination in greater numbers than the number of 
light sources. 
It is a further object of the present invention to provide a warning light 
for emergency vehicles having increased efficiency at reduced cost. 
It is a still further object of the present invention to provide a warning 
light for emergency vehicles comprised of three flashing points of 
illumination for each set of two light sources, one of the flashing points 
of illumination providing a high intensity narrow dispersion light beam 
visible at long range whereby the warning light is particularly adapted 
for use at accident sites on high speed roads.

Referring to the drawings, there is illustrated a light bar generally 
designated 10 for mounting on the roof of an emergency vehicle generally 
indicated 12. Light bar 10 comprises a housing having an opaque base 14 
and a transparent cover 16. Light bar 10 is suitably secured to the roof 
of vehicle 12, for example by brackets designated 18 interconnecting base 
14 and the vehicle roof. It will be appreciated that light bar 10 extends 
transversely of the vehicle, i.e., normal to the direction of vehicle 
travel. Mounted medially of light bar 16 is a conventional siren 20. 
Grills 21 are provided along front and rear sides of the light bar cover 
16 directly in front of and behind the siren 20. 
Within the light bar 10 and on each side of the siren 20 there is mounted a 
pair of sealed beam light sources 22. The pairs or sets of light sources 
22 are positioned to project two parallel light beams 24 and 26 parallel 
to the long axis of the light bar and transversely to respective opposite 
sides of vehicle 12. Light bar 10 carries a planar reflector 28 on each 
side thereof and in the path of light beams 24 and 26. Each planar 
reflector 28 carries a pair of reflective surfaces 30 and 32 on one side 
and another pair of reflective surfaces 34 and 36 on its opposite side. 
Each reflector 28 is carried for rotation on a vertically disposed spindle 
38 mounted in suitable bearings 39 at opposite ends of the spindle. Each 
spindle 38 thus defines a vertical axis about which its reflector 28 is 
rotated, the axis or spindle 38 being located between the pair of parallel 
light beams 24 and 26. A suitable drive mechanism, for example an 
electrical motor 37 coupled through gearing to the spindle 38, is provided 
wach reflector 28 whereby reflectors 28 are driven continuously in 
rotation. 
It will be appreciated from a review particularly of FIG. 2 that reflectors 
28, upon rotation thereof, provide four flashing points of illumination 
visible from both the front and rear sides of light bar 10, and hence from 
the front and rear of the vehicle. Particularly, when the left-hand 
deflector 28 of FIG. 2 obtains the rotary position illustrated, light 
beams 24 and 26 are reflected from surfaces 36 and 34 respectively such 
that the respective light beams 24' and 26' are respectively directed 
along parallel paths to the rear of the vehicle. Since reflector 28 is 
continuously rotating, reflected light beams 24' and 26' provide an on/off 
or flashing effect visible from the rear of the light bar 10. When the 
reflector 28 rotates, i.e., in the direction of the arrows, a distance of 
approximately 90 degrees, the light beams 24 and 26 are reflected by 
reflective surfaces 30 and 32 to provide a pair of forwardly reflected 
light beams which, due to the continuous rotation of deflector 28, appear 
as flashing points of illumination visible from the front of light bar 10. 
Consequently, four flashing points of illumination are visible from each 
of the front and rear sides of the light bar 10 by reflecting light from 
each set of light sources by the rotary reflector associated therewith. 
To provide flashing points of illumination of high intensity and narrow 
dispersion, i.e., points of illumination visible at considerable distances 
from the vehicle, there is provided on each of the opposite sides of light 
bar 10 an outboard reflector 40 having a concave reflective surface 42. 
Each reflector 40 is disposed outboard of the reflector 28 on the 
corresponding side of the vehicle and in the path of the rearmost light 
beam 24. From a review of the right-hand side of FIG. 2, it will be 
appreciated that light beam 24 will impinge upon and be reflected from the 
reflective surface 42 of reflector 40 when the reflector 28 between 
reflector 40 and light source 22 obtains a position parallel to the light 
beams 24 and 26. It will also be appreciated that the continuous rotation 
of reflector 28 provides a shuttering or on/off effect on light beam 24 as 
it impinges on reflector 40 whereby the light beam 24" reflected from 
surface 42 will appear as a flashing point of illumination. The outboard 
reflectors 40 in conjunction with this shutter action provide a reflected 
flashing light beam 24" or point of illumination of very high intensity 
and narrow angular dispersion. It is believed that the high intensity of 
this flashing point of illumination, as produced by the shuttering effect, 
is a result of the abrupt change in contrast and the retinal saturation 
characteristics produced by the square waveform of the energey pulse 
effected by the rotating reflector 28 interacting with the curved 
reflective surface 42 of reflector 40. Instead of the sinusoidal waveform 
produced by beacons of known construction, it is believed that this 
shuttering action produces a square waveform with a consequent long peak 
dwell which appears as a high intensity flashing point of illumination 
visible from long range. 
The outboard reflectors 40 are mounted on spindles 44. Spindles 44 may be 
rotated or indexed to selected angular positions. For example, spring 
biased detents can be provided to lock the reflectors 40 in selected 
angular positions. Manually operated handles or electrical drive means may 
be provided to index the outboard reflectors 40 into the various angular 
positions. It will be appreciated froma review of FIG. 2, that rotation of 
each of the reflectors 40 90.degree. to the position shown in dash lines 
will provide for reflection of the light beams 24 in a forward direction 
rather than rearwardly as illustrated. It is to be understood further that 
the outboard reflectors may each have a planar reflecting surface or a 
concave reflecting surface as illustrated in the drawing. 
It will also be appreciated from a review of the right-hand side of FIG. 2 
that a flashing light is also visible from each side of the vehicle. This 
results from reflector 28 obtaining a rotary position parallel to light 
beams 24 and 26. As illustrated, the rear light source, when reflector 28 
is positioned parallel to light beams 24 and 26, is reflected by reflector 
40 either rearwardly or forwardly depending on the position of deflector 
40. The other light beam, however, is not intercepted by reflector 28 and 
thus continues outwardly to one side of the vehicle as illustrated at 46. 
Reflector 28 also acts as a shutter with respect to this latter light beam 
to provide an on/off or flashing effect. 
Consequently, it will be appreciated that each reflector 28 cooperates with 
the corresponding pair of light sources and reflector 40 to substantially 
concurrently provide two flashing points of illumination visible from both 
the rear and front of the vehicle, a high intensity point of illumination 
visible over extended distances from either the front, rear and/or side of 
the vehicle, and a single flashing light visible from the side of the 
vehicle. The foregoing multiplicity of points of illumination on the light 
bar emanating, of course, from only two light sources. When two sets of 
the foregoing described reflectors 28 and 40 and light sources 22 are 
provided on opposite sides of the light bar, a warning light highly 
visible from all sides of the emergency vehicle is obtained and 
particularly from the front or rear of the vehicle depending upon the 
angular position of outboard reflectors 40. 
The invention may be embodied in other specific forms without departing 
from the spirit or essential characteristics thereof. The present 
embodiment is therefore to be considered in all respects as illustrative 
and not restrictive, the scope of the invention being indicated by the 
appended claims rather than the foregoing discription, and all changes 
which come within the meaning and range of equivalency of the claims are 
therefore intended to be embraced therein.