U.S. patent number 3,731,082 [Application Number 05/076,662] was granted by the patent office on 1973-05-01 for emergency warning light apparatus.
This patent grant is currently assigned to Lectric Lites Company. Invention is credited to Arnold O. Blaylock.
United States Patent |
3,731,082 |
Blaylock |
May 1, 1973 |
EMERGENCY WARNING LIGHT APPARATUS
Abstract
An emergency warning light apparatus having a high-intensity
bulb carried on a base and covered by a translucent, substantially
cylindrical dome, one portion of which has the form of a Fresnel,
ribbed pattern on a cylindrical wall surface and a conical
deflector in its upper portion, with its apex disposed from the
base of the cone toward the bulb. The base includes a lower plate
adapted for essentially universal mounting, including a central
aperture that is threaded to receive a support bar, a plurality of
smaller apertures clustered around the central aperture, and a
plurality of sockets on a lower surface to receive permanent
magnets. The high-intensity bulb carried by the base inside the
dome is intermitently actuated,being a strobe light connected with
a power transistor of a circuit means, the heat generated by the
transistor being conducted to the base by a heat conductive
fastener which with the base defines a heat sink to dissipate the
heat generated by the power transistor.
Inventors: |
Blaylock; Arnold O. (Fort
Worth, TX) |
Assignee: |
Lectric Lites Company (Fort
Worth, TX)
|
Family
ID: |
22133452 |
Appl.
No.: |
05/076,662 |
Filed: |
September 30, 1970 |
Current U.S.
Class: |
362/263; 340/981;
D26/123; 362/216 |
Current CPC
Class: |
B64D
47/06 (20130101); B64D 47/02 (20130101); B64F
1/20 (20130101); F21W 2111/06 (20130101) |
Current International
Class: |
B64F
1/20 (20060101); F21S 8/00 (20060101); B64D
47/00 (20060101); B64D 47/06 (20060101); B64F
1/00 (20060101); B64D 47/02 (20060101); B64f
001/20 (); F21v 021/00 () |
Field of
Search: |
;240/1.2,10.5,52.15,52B,3,10.66,6.4,52HT,41.3,41.36
;340/25,26,27,50 ;248/26A ;211/DIG.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Capozi; Louis J.
Claims
I claim:
1. An emergency or warning light apparatus comprising:
a base;
a high intensity bulb carried by and extending generally outward
from said base;
a translucent, substantially cylindrical dome secured to the base
to cover said bulb, said dome having a Fresnel, ribbed pattern on
its cylindrical wall surface to direct light rays from the bulb in
transverse planes to optimize eye level light intensity; and
a conical reflector carried in the upper portion of the dome,
having the apex disposed from the base of the cone toward the bulb,
said reflector limiting light energy dissipation through the top of
the done, but rather, deflecting upwardly traveling light rays in a
transverse direction.
2. The apparatus of claim 1 in which one half the included angle of
said conical deflector is within a range of 20.degree. to
30.degree. .
3. An emergency or warning light apparatus comprising:
a base;
a high intensity bulb carried by and extending generally outward
from said base;
a translucent, dome secured to the base to cover said bulb;
said base including a cylindrical bottom portion and a transverse
upper portion constructed of highly heat conductive metal;
a power transistor;
a fastener means constructed from a highly heat conductive metal
securing the power transistor to said base and defining therewith a
heat sink to transfer to the atmosphere the heat generated by the
power transistor.
4. The apparatus of claim 3 in which said power transistor has an
aperture and the fastener means extends through said aperture.
5. The apparatus of claim 3 in which said highly heat conductive
metal of the base is substantially aluminum.
6. The apparatus of claim 5 in which said fastener means is
constructed substantially of aluminum.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention:
This invention relates in general to emergency or warning lights,
particularly intermittently operated strobe lights that are
especially adapted for emergency vehicles.
2. Description of the Prior Art:
Previously, there have been commercially available in the United
States intermittently flashing warning lights that draw attention
to an emergency vehicle such as a fire truck, police car or
ambulance. Similar warning devices are used in other applications
such as in aircraft for night flying, for example, or on warning
barricades for highway or street construction or repair
projects.
There are a number of significant disadvantages associated with
previously known such lights, one being that the transfer
effectiveness of light from the bulb to persons to whom the warning
communication is intended is often low. Light rays defuse from the
bulb in directions from which a visible warning signal is not
needed. For example, essentially all the light transmitted
vertically upward from the bulb or those directed obliquely from
the bulb constitute a significant energy loss, since the persons to
be warned occupy a generally horizontal plane surrounding the
warning device. Thus, one purpose involved in this invention is the
provision of a warning light that limits light transmission to
effective directions.
In addition, intermittently flashing warning lights of the type
generally identified as strobe lights are commonly actuated by a
circuit utilizing solid state components including a power
transistor that generates a significant quantity of heat, which if
not efficiently transferred from the apparatus is capable of
decreasing the life span of certain circuit components. What is
provided with this invention, therefore, is a rugged and fail-safe
manner of transferring heat from the power transistor of such a
circuit to the atmosphere surrounding the emergency or warning
light apparatus.
Another problem commonly encountered in previously known emergency
or warning lights is that associated with the attachment of the
apparatus to an emergency vehicle or other supporting structure.
Since there are a number of methods for attaching such a light to
the support base, it is frequently necessary to extensively alter
the base of the light apparatus for installation, or else provide a
number of models which vary from one another only in the base. This
adds significantly to the installation time, or to inventory costs,
and is another problem to which this invention is directed.
OBJECTS OF THE INVENTION
Accordingly, it is the general object of this invention to provide
improved emergency or warning light apparatus.
Another object of the invention is to provide an emergency or
warning light apparatus that includes means for directing light
from the bulb in horizontal planes surrounding the light such that
light energy is not needlessly dissipated in directions where
persons needing the warning are unlikely to be located.
Another object of the invention is to provide in an emergency or
warning light apparatus, especially one classified as a strobe
light operated by a circuit including solid state components, a
means for dissipating heat in effective, rugged and reliable
manner.
Another object of the invention is to provide in an emergency or
warning light apparatus a mounting means that approaches
universality, meaning that it is capable of attachment to a wide
variety of supporting structures without need for substantial
modification, or necessity for keeping an inventory of various
models that differ from one another only with respect to the
mounting base.
These and other objects, as well as advantages, of this invention
will become apparent in the following.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an exploded, perspective view of warning or emergency
light apparatus embodying the principles of the invention;
FIG. 2 is a view of the dome or lens of the apparatus as seen in
longitudinal section to better expose its construction;
FIG. 3 is a fragmentary sectional view as seen looking along the
lines III--III of FIG. 2; and
FIG. 4 is a fragmentary, exploded, perspective view of means for
securing a power transistor to the housing in a manner to
efficiently transfer heat generated by the transistor to the
atmosphere to prevent component damage.
FIG. 5 is a bottom view of a base plate of the apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The emergency or warning light apparatus shown in FIG. 1 includes a
base 11 having a cylindrical bottom portion 13 and a transverse,
generally horizontal upper portion 15, both such portions
preferably being constructed of a highly heat conductive metal such
as aluminum or aluminum alloy (both referred to hereinafter as
being substantially aluminum).
Supported upon the base is a translucent, substantially cylindrical
dome 17 having a lower cylindrical wall portion 19, an outwardly
extending flange 21 protruding thereform, and a transversely or
horizontally extending top enclosure 23. The flange 21 of the dome
or lens is secured to the base 11 by an annular fastener 25 which
is secured to the base by a plurality of suitable fastener devices
such as the screws 26 that are received in suitable mating
apertures in the annular fastener 25 and the cylindrical bottom
portion 13 of the base. The lens is constructed of a translucent,
sometimes transparent material, such as clear plastic or glass, to
which a suitable dye is added during construction to provide the
selected lens color. As perhaps best seen in FIG. 2, the exterior
wall of the upper cylindrical portion has a ribbed configuration,
with ribs 27 extending circumferentially around the lens, such ribs
forming discrete triangles as seen in the longitudinal section of
FIG. 2, such that the hypotenuse of the ribs increases in length
and decreases in angle relative to vertical progressively from the
upper and lower cylindrical portions of the lens, toward a groove
29 in the approximate mid-section of the lens, such groove having
essentially vertical bottom surfaces and horizontal side surfaces
as shown. This lens configuration is generally known as the
"Fresnel" lens, named in honor of Augustin Jean Fresnel
(1788-1827), the celebrated French physicist. Light rays radiating
from a bulb placed in a central location on the interior of the
lens are deflected horizontally by the surfaces seen as hypotenuses
in the cross-sectional view of FIG. 2, thus minimizing dissipation
of energy in upward or downward directions where light transmission
is not needed or required.
As shown in the fragmentary sectional view of FIG. 3, the
circumference 31 of each section of the Fresnel lens forms a
continuous, circular line, while the interior, circumferential
surface 33 of the lens comprises a series of abutting, segments of
circles to diffuse the light for the purpose of making it appear to
fill the dome rather than radiate from one point.
Inserted into the upper portion of the Fresnel lens shown in FIG. 2
is a conical reflector 35 carried in the upper portion of the dome
by attachment with a suitable epoxy resin 37 secured to the base of
the conical reflector and to the peripheral interior surface of the
top 23 of the dome. The apex 37 of the conical reflector is
disposed toward the bulb, said reflector thus limiting light energy
dissipation through the top of the dome, and rather, deflecting
upwardly traveling light in a transverse or horizontal direction,
generally complimentary with the ribs of the Fresnel lens. While
the conical reflector does not reflect light rays radiating from
the bulb in parallel, horizontal paths in the manner of the Fresnel
portion of the lens, it nonetheless deflects the light rays toward
the cylindrical Fresnel portion of the lens such that this latter
portion directs the light rays in the finally desired, generally
horizontal or transverse directions, where the rays are easily seen
by a viewer. A conical reflector 35 may be constructed of any
suitable light reflecting material, or alternatively may have a
light reflective coating 39 placed on the interior conical section.
Preferably, the angle of the cone with the base of the cone, as
seen in FIG. 2, lies within a range of 20.degree. to 30.degree.
.
As seen in FIG. 1 and extending upwardly from the transverse upper
portion 15 of the base is a pedestal 41 which receives and supports
a bulb 42 that preferably is a "Xenon" bulb of a type and
configuration commonly used as a strobe light. Such bulbs are
commercially available and when energized with a suitable quantity
of electrical energy create light through the process of ionizing
the xenon gas inside a transparent or translucent tube 43. While
xenon filled bulbs are presently preferred, the invention is not
limited to use with any particular light source.
When utilizing a strobe type light source, the electrical energy
transmitting circuit commonly utilizes solid state circuitry that
includes a power transistor 45 which generates significant
quantities of heat. Since the circuitry (not shown) is enclosed
within the base 11, which is preferably sealed to prevent the
ingress of moisture and other matter potentially harmful to the
circuitry the heat generated by the circuitry is capable of
increasing to such an extent that damage to circuit components is
possible. A significant portion of the heat build-up is caused by
the power transistor, and thus FIG. 4 discloses a means for
transferring the heat from the power transistor to the exterior of
the base, where it may be better dissipated into the
atmosphere.
If the base 11, shown partially in FIG. 4, is constructed of a
highly heat conductive metal such as aluminum or aluminum alloy,
the power transistor 45 may be secured directly thereto with a
fastener means 49, in this instance a bolt with threads 47,
extending through aperture 48, and nut 51, also constructed of a
highly heat conductive metal, preferably an aluminum alloy, though
possible of a less conductive material such as steel, such that the
heat in the transistor is transmitted through the heat sink which
consists of the fastener metal and the metal of the base. By this
means, heat is dissipated into the atmosphere and thus, does not
rise to levels capable of damaging the other, frequently heat
sensitive, components of the circuitry.
With reference to FIG. 1, the base includes a lower plate 53
secured to the remainder of the base with fasteners 55 that extend
into mating apertures respectively located in the plate 53 and the
cylindrical bottom portion 13 of the base. A central aperture 57 is
formed in the base and threaded as indicated to receive a threaded
support bar (not shown), which is common means of mounting
emergency or warning lights to vehicles or other supporting
structure. In addition, a plurality of smaller aperture 59,
threaded if desired, are clustered around the central aperture for
the purpose of receiving fasteners for securement to a mounting
plate or bracket in the support structure.
Finally, a plurality of sockets 61 that protrude inwardly from a
bottom surface 63 of the base plate each receive a magnet 65,
secured therein by suitable means such as epoxy resins for the
purpose of enabling magnetic attachment to a support structure.
Hence, the light apparatus may be secured to support structure in
any one of a number of convenient manners.
It should be apparent from the foregoing that an invention having
significant advantages has been provided. A combination of a
translucent or transparent dome having a Fresnel lens configuration
and a conical reflector increases the operating efficiency and
effectiveness of the light apparatus by minimizing the radiation of
light energy in directions where those persons needing warning are
uncommonly located. Moreover, the problem of heat increase and
component damage is minimized by the above-described method of
securing a power transistor to a heat conductive housing to
dissipate heat into the atmosphere. In addition, the base structure
described above enables connection of the light apparatus to a
supporting structure by a variety of methods, a time conserving and
inventory saving feature of the invention.
While the invention has been shown in only one of its forms, it
should be apparent to those skilled in the art that it is not so
limited but is susceptible to various changes and modifications
without departing from the spirit thereof.
* * * * *