Note: Descriptions are shown in the official language in which they were submitted.
1~146~6~
WARNING REFLECTOR
This invention pertains to a warning reflector.
Warning reflectors are optical means particularly intended
to avoid traffic accidents as between moving vehicles and
animals at night. Many serious accidents occur near foxested
areas when animals such as deer are struck by fast-moving
vehicles while crossing unlit roads during night time hours.
In the Austrian patent specification 317 729 a
warning reflector for deer is described consisting basically
i 10 of a prism plate which is sealed in a housing so that it is
watertight. The erection of these known warning reflectors
$or deer have led to a considerable reduction of the number
of accidents.
In known warning reflectors for warning animals
such as deer of oncoming vehicles the entering light rays
~.
are diverted by a planar prism surface to a back surface of
the prism surface and are totally reflected therefrom. The
light emerglng from a concave prism surface is more or less
dispersed in accordance with the curvature of the ~urface.
.. 1
. . . I
1'6 ~461E~
':
- 2 - t
Known warning reflectors possess the disadvantage
of consisting of several individual parts which give rise to
high production and assembly costs. Further, the necessity
of a watertight housing employed in known reflector con-
structions is a disadvantage. Finally, known warning
reflectors do not allow for variation in light ray reception
and reflection by simple adjustment of the optically effective
elements.
It is, therefore, the object of the invention to
provide a warning reflector which is of simple design,
resistant to weather, and which allows for variation of the
reflected light paths in a simple manner.
This invention is based on the knowledge that this
object can be achieved by means of a warning reflector, the
reflection surface of which comprises several torus surfaces
arranged side-by-side.A torus surface is a surface o.f re-
volutlon sha~éd like an anchor rlng. It is generated by
rotating a clrcle about a non-intersecting coplanar line
as axls.
Other objects of this invention will become
apparent from the following detailed description when read
in the light of the drawing and appended claims.
One embodiment of the invention comprises a warning
reflector composed of a transparent plate having a light-
~5 entrance surface and a reflective layer on a rear plate
surface from which the reflected light is dispersed by means
of several curved surface portions defining the rear surface
and arranged side-by-side. The reflector plate is characterized
by the fact that the curved surface portions of the rear
surface are arranged opposite the light-entrance surface and
comprlse torus surfaces which support the reflective layer. '~
The invention further comprises a method of manu-
facturing a warning reflector wherein a metal sheet coated
with transparent plastic is inserted into a forming tool and
... .. . - ~ , . - - ..... - ........ , ~ ,-. .
- i . . ......... . . . ... . . . . . . .
- - . , . - . . . . :
~: . : : . ,
_ 3 _
additional transparent plastic is applied to the sheet, and
the metal sheet coated with plastic is simultaneously formed
and fused to the applied plastic at an elevated temperature
thereby forming the reflector.
In accordance with an al~ernative embodiment for
the manufacture of a warning reflector, a plastic band
having an enclosed metal sheet is rendered pliable by the
addition of heat and formed out by stamping.
In accordance with a preferred embodiment the
optical axes of the torus surfaces form an angle with the
perpendicular to the light entrance surface both in the
horizontal and in the vertical direction.
The torus surfaces of the reflector may be either
convex or concave.
The warning reflectors made in accordance with the
invention are characterized by the fact that their construction
is very simple. In particular, the warning reflector can be
embodied in a one-piece construction and is resistant to
external i~fluences, particularly the influence of weather
and dirt. The entering light is reflected in a punctiform
manner from the individual toroidal surfaces. By virtue of
the arrangement of several side-by-side toroidal surfaces
the illumination of the total surface can be achieved and
thus a high optical efficiency can be guaranteed.
By variation of the optical axes of the individual
toroidal surfaces simple and extensive variation of the
course of the light rays is possible. On the other hand,
this can be exploited by arranging the warning reflector at
a smaller angle to the entering light ray. This leads to the
enlargement of the active light-entrance surface. Further,
it is possible to adapt the reflected light to the ground
conditions, i.e., to direct the reflected light more upwardly
or downwardly as the case requires. The course of the rays
: .. .. .. :: ,. :. . : .. .: . :
`: :
`` ~5,.~.~$~
- 4 -
may also be varied in relation to the road by changing the
optical axes of the torus surfaces. Finally, it is possible
to arrange the optical axes of individual torus surfaces or
individual groups of torus surfaces differently which means
that further variations of the course of the rays can be
achieved. This will be explained in more detail hereinafter.
Hereinafter, the invention will be explained in
greater detail with reference to the drawing which shows
examples of embodiments.
Figure l gives a plan view of a warning reflector
made in accordance with the invention;
Figure 2 is a cross-sectional vi0w along the line
A-A of Figure l;
Figure 3 shows a warning reflector mounted on a
guide post as well as the course of the light rays striking
the same;
Figure 4 is a top view of the warning reflector
of Figure 3;
Figure 5 show~ the image of the rays from the warning
reflector of Figures 3 and 4;
Figure 6 shows the illumination of the ground by
means of warning reflectors made pursuant to this invention; and
Figures 7 and 8 are cross-sectional views of a forming
tool for manufacturing a warning reflector of this invention.
A plan view of a warning reflector for deer is
shown in Figure l. It comprises a transparent plate 2. This
plate consists preferably of a transparent plastic. Acrylic
glasses, cellulose esters as well as cellulose acetates and
cellulose acetobutyrates and polystyrols comprise suitable
materials of composition for plate 2.
The thickness of the plate 2 depends basically on
the selected division and the desired dispersion of the
reflected light. In general, the thickness of the plate
amounts to between 2 and 5 mm; for reasons of cost the
plates are adapted to be as thin as possible.
The size of the plates can be selected as desired.
As they are usually affixed to road guide posts, they usually
assume the shape of a rectangle having a height ranging from
between S to 15 cm and width ranging from between 3 to 10 cm.
The division of the warning reflector into individual
torus surfaces 5 can be extensively varied. The division
depends on the desired dispersion and on the radii of the
torus surfaces. A narrow division is selected if at a short
distance from the reflector the latter is required to have a
fully illuminated surface. By way of example, 3 to 20
toroidal surfaces may be arranged side by side in the
horizontal direction and 5 to 30 in the vertical direction.
A suitable embodiment exhibits approximately 80 to 100
individual toroidal surfaces.
In Figure 2 the embodiment of the reflection
surface 4 in the form of individual surfaces 5 is clearly
visible. The plate 2 bears a reflective layer 6 on the side
opposite the light entrance surface 3. The reflective layer
i8 normally a metal layer, e.g., an aluminum or silver layer.
The application of these layers, for instance, by means of a
high vacuum coater, is known. Alternatively, the reflective
layer 6 may comprise an aluminum sheet coated with plastic
on one or both sides and connected in a suitable manner to
the plate 2. To protect the reflective layer, a suitable
protective layer 7, e.g., a lacquer layer, may be provided.
~he light-entrance surface 3 is preferably slightly
curved in order to avoid undesired surface reflection.
The plastic plate 2 may be colored, e.g., red or
green. According to the opinions of behavioural research
scientists, animals such as deer respond particularly well
to these colors in reflector devices of this type.
The selection of the radii for the individual
torus surfaces 5 depends on the desired light dispersion
and on the division. Suitable radii lie in the ran~e of
between 5 and 25 cm. A smaller radius, e.g., between
5 and 15 cm, is mostly selected for the curvature in the
horizontal direction because a wider angle of dispersion
of up to approximately + 28 is preferred. The radius
of the torus surfaces for the curvature in the vertical
direction is in general larger and should lie preferably
in the range of 15 to 25 cm. The provision of a very wide
dispersion angle, for instance large horizontal fanning
for a winding landscape, may also be employed when the
surrounding terrain ~o warrants. In such cases one radius
of the torus surface may also be infinite.
Angles of dispersion amounting in the horizontal
direction to between + 10 and + 30, in particularly
amounting to approximately + 25, and amounting in the
vertical direction to between + 4 and ~ 10 for the normal
reflector as well as to between + 10 and + 30 for a
reflector disposed adjacent an embankment are normally
preferred.
Figure 3 illustrates in perspective a warning re-
flector 1 attached to a guide post 13. Also, the course of the
light from a motor vehicle approaching each of the two sides
is shown for the central beam Imain and emergent direction).
Figure 4 shows in top plan view the warning
reflector 1 mounted on a guide post 13, and the course of
the light rays striking the same. In the case of the
entering light being approximately parallel to the side of
the road, the inclination of the reflection plate 2 must
be at an angle of 45 to the entering light if the main
direction of reflection is intended to be perpendicular to
the entering ray of light or perpendicular to the road.
~ : . - . ."~ . ;
-
-- 7 --
In the latter case the angle enclosed by both plates must
amount to 90. By arranging the plates at an angle of 45
to the entering light the active light entrance surface
is reduced.
S In accordance with a preferred embodiment, the
warning reflector can be arranged in such a manner that the
angle between the two plates 2 is smaller than 90. In
so doing the active light-entrance surface and thus the
optical effect is increased. In accordance with a preferred
embodiment, the angle between the two plates 2 amounts to
approximately 60. In such disposition if it is desired
that the main direction of the reflection be perpendicular
to the entering light beam, this can be achieved by arranging
the optical axes of the torus surfaces at an angle to the
perpendicular to the light-entrance surface. In this case
the angle a (Figure 2) amounts to approximately 12.
By varying the angles between the optical axes
of the torus surfaces and the perpendicular to the light-
entrance surface it is possible to vary to any degree the
illumination of the ground, the dispersion remaining
constant. The illumination of the ground effected when the
main direction of reflection is perpendicular to the road
and horizontal is shown in Figure 6. By varying the angle of
the optical axis, the main direction of reflection and hence
the illumination of the ground can be varied as desired.
In order to achieve high light intensities it iB
preferable to maintain the dispersion of the reflected light
low in the vertical direction. In Figure 5 the fanning of the
light i8 shown schematically. The dispersion in the
horizontal direction is indicated by ~H and the dispersion in
the vertical direction by ~V. Since the ground bordering
the road often falls down from the road or forms an embank-
ment, the variation of the main direction of reflection
. , .,, , . : . . ... ;. -.. . : :. :.
,.. . ~ . - :.... . ....
may be downwardly or upwardly from the horizontal to
achieve optimum ground illumination at high light intensity,
depending on the ground condition. Desired angular re-
flection may be effected by corresponding inclination of the
reflective plates 2 or of the whole warning reflector 1.
Both measures, however, give rise to adjustment
problems which make the fixture of the warning reflector
to the guide post difficult. The use of positioning wedges
causes difficulties when automatic cleaning is carried out,
and also causes difficulties from the point of view of
transport technology because thus the aspect of signal of
the guide post is changed to a large extent. In warning
reflectors made in accordance with this invention, the
variation of the main direction of reflection in the vertical
direction can, however, be achieved by simply inclining the
optical axes of the torus surfaces towards the perpendicular
to the light entrance surface. Hence, the warning reflector
can be adapted to all forms of terrain in a simple manner.
In particular, "embankment warning reflectors
for animals" may be devised in which the main direction
of reflection deviates from the horizontal line, this
deviation amounting by way of example to an angle of lO,
20 and 30.
The provided reflector construction also enables
; 25 the optical axes of individual torus surfaces or individual
groups of torus surfaces, for instance of individual
perpendicular rows, to be arranged at various angles to the
perpendicular to the light-entrance surface. Thus, on the
approach of a motor vehicle a change in the direction of
reflection i9 effected which presents itself as a glittering
or glimmering when the despersion of the light is low.
The arrangement of the torus surfaces of the
provided reflectors in a m~nner whereby the optical axes
thereof are at an angle tothe perpendicular of the light-
entrance ~urface can be carried out by suitably inclining
the torus surfaces.
:, . . , , . , -
~ . . . . ;
; , : - :-..... - ., . , . :,
, - . : . . ... , - ..... .-, - . . :
. .~. . .,.. : .. - . ..
.
It may also be advantageous to incline the optical
axes of the torus surfaces in various portions of the reflector ~-
plate at various angles in order to cover a lar~e range of
dispersion when the dispersion is relatively low and hence
the light intensity is high. Thus, one group of torus
surfaces may, for instance, cause a dispersion amounting to
between 20 and 40 and another group may cause a dispersion
amounting to between 40 and 60.
For the purpose of mounting, the plates 2 may be
enclosed in a housing, e.g., made of plastic, and this housing
may be attached to the guide post.
It is preferred to embody the warning reflectors in
`~ a single piece. It then consists of only two plates arranged
at an angle to each other and a suitable attaching means for
lS mounting on the guide post. The advantages of the one-piece
embodiment lie in the fact that its manufacture is simple,
the cost~ of production are low, and it can be simply cleaned.
A further suitable possibility of manufacture is
seen in the forming out of the plates 2 and framing the
same with plastic to form the finished warning reflector.
The manufacture of the plates 2 or the warning
reflector comprising two plates arranged at an angle and
embodied in one piece may be carried out by injection die-
casting. Alternatively, the plates may be manufactured in
a suitable forming tool in which they are shaped by molding.
A preferred method of manufacturing the plates is
illustrated in Figures 7 and 8. A metal sheet 11, e.g.,
an aluminum sheet, coated with transparent plastic is
introduced into an injection die-casting tool 10. This is
shown schematically in Figure 7. Then the plastic for forming
the plate is introduced into the injection die-casting tool.
The forming out of the plastic plate and the connection of
the introduced plastic 12 with the plastic coating provided
on the metal sheet 11 is then carried out simultaneously at
.-. . .,; .
.. : - ,. - . .... ;;. .: -,.
- 10 -
an elevated temperature. The formed article is shown in
Figure 8. Utilizing this method of manufacture, a reflector
plate is obtained in which the metal sheet is completely
surrounded by plastic and in which a secure engagement
between the metal sheet and the plastic is achieved in a
simple manner.
According to an alternative embodiment, the plates
of the warning reflector may be manufactured from a plastic
band with an enclosed metal sheet. The plastic coating on
both sides of the metal sheet may vary in thickness. Its
thickness depends on the desired thickness of the finished
plates. A plastic band of this kind is rendered pliable by
the addition of heat and is formed in a suitable forming
tool by stamping.
It is preferred to have the plastic coating on the
rear surface of lesser thickness. It is also possible to
provide a plastic coating on only one side of a metal sheet.
A further method of manufacturing the plates 2 of
the warning reflector comprises forming out the plates from
tran parent plastic by means of injection die-casting and
then providing such plates with a reflective layer, e.g., by
applying aluminum in a high vacuum coater.
The function of the warning reflectors for animals
such as deer can be seen from Figure 6. When a motor vehicle
approaches, the rays entering the reflectors are reflected
into the surrounding terrain and the animal is deterred from
crossing the road 14 because of the optical signals. It is
also possible to arrange the warning reflectors for deer on
the oppoYite side of the road and facing towards the road.
It is believed that the foregoing has made obvious
a number of modifications of the provided reflectors which
are within the ambit of the invention disclosed. This
i~vention, therefore, is to be limited only by the scopy of
the appended claims.
WHAT IS CLAIMED IS:
