U.S. patent application number 10/155162 was filed with the patent office on 2002-10-10 for environmental shroud.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS, N.V.. Invention is credited to Jones, Theodore L., Ryan, Christopher J..
Application Number | 20020145677 10/155162 |
Document ID | / |
Family ID | 23379518 |
Filed Date | 2002-10-10 |
United States Patent
Application |
20020145677 |
Kind Code |
A1 |
Ryan, Christopher J. ; et
al. |
October 10, 2002 |
Environmental shroud
Abstract
The invention provides an environmental shroud (190, 290, 390)
and a camera assembly (10, 20, 30) including the shroud. The
environmental shroud (190, 290, 390) absorbs and dissipates heat
energy that is not reflected and heat energy that is generated by
the contents of the camera housing so that the camera housing
temperature does not exceed the maximum rated temperature. In one
embodiment, the camera assembly includes a camera housing (130)
having a mounting cap (140) attached to sidewalls (126) to which is
attached an optical surface (135), the camera housing enclosing a
camera system; and an environmental shroud (190) attached to the
camera housing . The shroud has a lower section (100) having
sidewalls (126A) that descend to a drip edge (108), and at least
one vent (105) in a top portion; and an upper section (120), at
least the lower section having means that reflects or deflects
radiant heat energy and means to remove unreflected or undeflected
heat from the camera housing (130) through said vent (105), the
upper section (120) covering the vent (105) and having a lower edge
(125) situated below the vent and over the sidewalls (126A) to
provide a tortuous path which prevents the penetration of water
into the camera housing (130).
Inventors: |
Ryan, Christopher J.;
(Lancaster, PA) ; Jones, Theodore L.; (Akron,
PA) |
Correspondence
Address: |
Corporate Patent Counsel
Philips Electronics North America Corporation
580 White Plains Road
Tarrytown
NY
10591
US
|
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS,
N.V.
|
Family ID: |
23379518 |
Appl. No.: |
10/155162 |
Filed: |
May 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10155162 |
May 24, 2002 |
|
|
|
09351088 |
Jul 9, 1999 |
|
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|
Current U.S.
Class: |
348/373 ;
348/151 |
Current CPC
Class: |
G08B 13/196
20130101 |
Class at
Publication: |
348/373 ;
348/151 |
International
Class: |
H04N 005/225 |
Claims
We claim:
1. A camera assembly (10) which comprises: a camera housing (130)
having a mounting cap (140) attached to sidewalls (126) to which is
attached an optical surface (135), the camera housing enclosing a
camera system; and an environmental shroud (190) attached to the
camera housing and effective to reflect and/or deflect heat energy,
dissipate heat energy not reflected or deflected, and protect the
camera housing from the ingress of moisture, wherein said shroud
comprises a lower section (100) having sidewalls (126A) that
descend to a drip edge (108), and at least one vent (105) in a top
portion thereof; and an upper section (120), at least the lower
section having means that reflects and/or deflects radiant heat
energy and means to remove unreflected and undeflected heat from
the camera housing (130) through said vent (105), the upper section
(120) covering said vent (105) and having a lower edge (125)
situated below the vent and over the sidewalls (126A) of the shroud
to provide a tortuous path which prevents the penetration of water
into the camera housing (130).
2. A camera assembly as claimed in claim 1, wherein the shroud is
formed of aluminum.
3. A camera assembly as claimed in claim 1, wherein the means for
reflecting or deflecting radiant energy is a coating on at least
one surface of said shroud having a specified emissivity.
4. A camera assembly as claimed in claim 1, wherein a ridge (103)
is formed in front of the vent 105 to further assist in the removal
of water from said vent.
5. A camera assembly (30) which comprises: a camera housing (330)
having a mounting cap (340) attached to sidewalls (326) to which is
attached an optical surface (135), the camera housing enclosing a
camera system; and an environmental shroud (390) attached to the
camera housing and effective to reflect and/or deflect heat energy,
dissipate heat energy not reflected or deflected, and protect the
camera housing from the ingress of moisture, wherein said shroud
comprises a section (300) having sidewalls (326A) that descend to a
drip edge (308), and at least one louvre vent (305) in a top
portion thereof; at least a portion of the section (300) having
means that reflects and/or deflects radiant heat energy and means
to remove unreflected or undeflected heat from the camera housing
(330) through said louvre vent (305), the louvre vent having a
lower edge (325) situated over the sidewalls (326A) of the shroud
to provide a tortuous path which prevents the penetration of water
into the camera housing (330).
6. A camera assembly (20) which comprises: a camera housing (230)
having a mounting cap (240) attached to sidewalls (226) to which is
attached an optical surface (135), the camera housing enclosing a
camera system; and an environmental shroud (290) attached to the
camera housing and effective to reflect or deflect heat energy,
dissipate heat energy not reflected and/or deflected, and protect
the camera housing from the ingress of moisture, wherein said
shroud comprises an outer shroud section (200) having sidewalls
(226A) that descend to a drip edge (208), and at least one vent
(205) in a top portion thereof, and an inner shroud section (220)
having at least one vent (228) in a top portion thereof and at
least one water channel (225) located below the vent (228)and
leading to a portion of the sidewall (226A), the outer shroud vent
(205) and the inner shroud vent (228) being coincident and offset
relative to each other and communicating with said water channel
(225) to provide a tortuous path which prevents the penetration of
water into the camera housing (230), at least a portion of the
outer shroud section (200) having means that reflects and/or
deflects radiant heat energy and means to remove unreflected or
undeflected heat from the camera housing (230) through said vents
(205, 228).
7. A camera assembly as claimed in claim 6, wherein water entering
the outer shroud vent (205) is directed to the water channel(225)
onto the sidewall (226A) and onto the drip edge (208) away from the
camera housing (230).
8. A camera assembly as claimed in claim 6, wherein at least a pair
of bimetallic strips (241) are positioned over the outer shroud
vents (205).
9. A camera assembly as claimed in claim 8, wherein the bimetallic
strips (241) are actuatable to close the vents when the temperature
falls below a predetermined level.
10. An environmental shroud (190) attached to a housing (130)
having a top portion (140) attached to sidewalls (126) to which is
attached a bottom wall, said environmental shroud (190) being
effective to reflect and/or deflect heat energy, dissipate heat
energy not reflected or deflected, and protect the housing from the
ingress of moisture, wherein said shroud comprises a lower section
(100) having sidewalls (126A) that descend to a drip edge (108),
and at least one vent (105) in a top portion thereof; and an upper
section (120), at least the lower section having means that
reflects and/or deflects radiant heat energy and means to remove
unreflected and undeflected heat from the housing (130) through
said vent (105), the upper section (120) covering said vent (105)
and having a lower edge (125) situated below the vent and over the
sidewalls (126A) to provide a tortuous path which prevents the
penetration of water into the housing (130).
11. An environmental shroud as claimed in claim 10, wherein the
shroud is formed of aluminum.
12. An environmental shroud as claimed in claim 10, wherein the
means for reflecting or deflecting radiant energy is a coating on
at least one surface of said shroud having a specified
emissivity.
13. An environmental shroud as claimed in claim 10, wherein a ridge
(103) is formed in front of the vent 105 to further assist in the
removal of water from said vent.
14. An environmental shroud (390) attached to a housing (330)
having a top portion (340) attached to sidewalls (326) to which is
attached a bottom wall, said environmental shroud (390) being
effective to reflect and/or deflect heat energy, dissipate heat
energy not reflected or deflected, and protect the housing from the
ingress of moisture, wherein said shroud comprises a section (300)
having sidewalls (326A) that descend to a drip edge (308), and at
least one louvre vent (305) in a top portion thereof; at least a
portion of the section (300) having means that reflects and/or
deflects radiant heat energy and means to remove unreflected or
undeflected heat from the housing (330) through said louvre vent
(305), the louvre vent having a lower edge (325) situated over the
sidewalls (326A) to provide a tortuous path which prevents the
penetration of water into the housing (330).
15. An environmental shroud (290) attached to a housing (230)
having a top portion (240) attached to sidewalls (226) to which is
attached a bottom wall, said environmental shroud (290) being
effective to reflect or deflect heat energy, dissipate heat energy
not reflected and/or deflected, and protect the housing from the
ingress of moisture, wherein said shroud comprises an outer shroud
section (200) having sidewalls (226A) that descend to a drip edge
(208), and at least one vent (205) in a top portion thereof, and an
inner shroud section (220) having at least one vent (228) in a top
portion thereof and at least one water channel (225) located below
the vent (228)and leading to a portion of the sidewall (226A), the
outer shroud vent (205) and the inner shroud vent (228) being
coincident and offset relative to each other and communicating with
said water channel (225) to provide a tortuous path which prevents
the penetration of water into the housing (230), at least a portion
of the outer shroud section (200) having means that reflects and/or
deflects radiant heat energy and means to remove unreflected or
undeflected heat from the housing (230) through said vents (205,
228).
16. An environmental shroud as claimed in claim 15, wherein water
entering the outer shroud vent (205) is directed to the water
channel(225) onto the sidewall (226A) and onto the drip edge (208)
away from the housing (230).
17. An environmental shroud as claimed in claim 16, wherein at
least a pair of bimetallic strips (241) is positioned over the
outer shroud vents (205).
18. An environmental shroud as claimed in claim 17, wherein the
bimetallic strips (241) are actuatable to close the vents when the
temperature falls below a predetermined level.
Description
FIELD OF THE INVENTION
[0001] This invention relates to indoor/outdoor surveillance
equipment and systems, and more particularly, to an improved camera
assembly which has a housing that includes an environmental
shroud.
BACKGROUND OF THE INVENTION
[0002] Closed-circuit surveillance equipment is well established
and can include fixed-position cameras and zoom lenses mounted on
pan and tilt mechanisms which are typically controlled by security
personnel. In outdoor locations, an enclosure for the camera
housing is usually employed and domed housing for such cameras are
desirable due to their appearance as well as the fact that the
camera itself is not easily visible, though the camera can scan a
wide area.
[0003] In a typical outdoor camera enclosure, a single main housing
part is utilized, wherein a top thereof is connected to a pipe.
Electrical connections are generally routed from a main power
source through the pipe and into the housing. In addition, a
hemispheric dome and additional internal components, such as the
camera power supply, camera body, lens, pan & tilt mechanism,
and controller electronics, are removably attached to an inside of
the single housing part. Such camera assemblies are subject to
damage and require means to protect the camera from moisture and
precipitation, extremes in temperature, and unauthorized tampering.
For example, some conventional housings permit rain water or other
moisture to accumulate and run down the conical side of the housing
and onto the dome itself. Another concern is with the heat caused
by sunlight or generated in the housing during use of the camera
and the need to deflect such heat energy and /or to dissipate the
same from the camera housing to prevent damage thereto.
[0004] Prior attempts to address some of these problems include
U.S. Pat. No. 4,320,949 which, for example, in one embodiment
provides a housing with a cover with a skirt over which rainwater
may flow, form pendant drops, and fall, and a camera mount adapted
to carry a camera and a camera positioning motor. A dome
unidirectionally transparent to light is secured to the cover. The
cover and dome form an air space between them. A fan is disposed in
a side wall of the upper support housing to provide forced cool air
circulation in the housing to cool the housing when the temperature
reaches a certain predetermined level. The assembly also includes
heaters which are operated when the temperature in the housing
approaches freezing. In a second embodiment, air is brought into
the assembly by natural circulation, i.e. a space or inlet area is
provided at the interface of the support housing and cover member
so that air can naturally enter the support housing about the
circumference of the housing. This air is circulated downwardly
adjacent the inner a wall of the cover member and then up into the
support housing where it is exhausted through an air exhaust
port.
[0005] In U.S. Pat. No. 5,689,304, commonly assigned herewith,
there is disclosed a surveillance housing assembly which comprises
an outer shell having a top wall portion and side wall portion,
wherein the side wall portion extends in a downward direction from
the top wall portion to thereby define a first cavity. An inner
shell comprises a top wall portion for mounting engagement with an
underside of the top wall portion of the outer shell within the
first cavity. The inner shell further comprises a top wall portion
and a side wall portion, wherein the side wall portion extends in a
downward direction from the top wall portion to thereby define a
second cavity. The top wall portion 18 of the outer shell 12 has an
exhaust aperture 32 positioned off-center from a central axis 34 of
the outer shell; a generally circular aperture 36 is centered on
the central axis and is provided in the top wall portion 18 to
enable cable to pass through; and the top wall portion 22 of the
inner shell 14 has an air exhaust aperture designed to be
coincident with the air exhaust aperture 32 of the top wall portion
18 of the outer shell 12; and still further, the top wall portion
22 of the inner shell 14 has a generally circular aperture which is
coincident with the aperture 36. Air inlet apertures 44 define an
air flow to exhaust 32. The housing also has a decorative cap 70
which has a plurality of notches along its bottom edge which,
cooperate with other parts to provide a path for an exhaust air
flow and provides for protection against an ingress of unwanted
water. This assembly also comprises various combinations of heaters
and blowers. Further in this arrangement, a sequence of wall
surfaces and plateau surfaces are arranged for securing components
of the surveillance equipment thereto in a prescribed manner such
that first components of the surveillance equipment are disposed in
between the underside of the outer shell and an outerside of the
inner shell, and second components of the surveillance equipment
are disposed within the second cavity.
[0006] While air circulation via fans and exhaust ports and/or
air-intake valves and air-exhaust valves is satisfactory to
compensate for environmental temperature changes in some
surveillance systems, it has its limitations, most notably in terms
of added cost and complexity, size and power constraints occasioned
by the need to incorporate such components into the surveillance
assembly.
[0007] There remains a need in the art for a camera surveillance
system which does not suffer from the disadvantages set forth above
and which provides protection to the camera from moisture and heat
without imposing undesirable size and power constraints.
SUMMARY OF THE INVENTION
[0008] An object of the invention is to provide a camera housing
with an environmental shroud which is designed to deflect or
reflect the radiant heat energy generated by the sun or any other
heat source so that the heat does not penetrate the camera
housing.
[0009] Another object of the invention is to provide a camera
housing having an environmental shroud which absorbs and dissipates
heat energy that is not reflected from radiation and heat energy
that is generated by the contents of the camera housing so that the
camera housing temperature does not exceed the maximum rated
temperature.
[0010] Another object is to provide such an environmental shroud
which protects the camera housing from rain or any other type of
moisture by providing a tortuous path for which prevents water
penetration inside the environmental shroud.
[0011] Yet another object of the invention is to provide an
environmental shroud having a "drip edge" so that the water has a
means of falling off the environmental shroud to avoid obstructing
the optical surface of the camera housing.
[0012] These and other objects of the invention are accomplished by
a camera assembly having a housing which comprises an environmental
shroud having a configuration which reflects and/or deflects heat
energy, dissipates heat energy not reflected and/or deflected,
protects the camera from water or other moisture, and enables a
high level of heat dissipation even when the camera is operated in
sunlight at high ambient temperature.
[0013] Preferably, the environmental shroud includes a coating to
deflect the heat energy and a vent to dissipate the heat energy. In
the most preferred embodiments, the shroud also includes a drip
edge for water or moisture to run off of the camera housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A shows an external view of a first embodiment of a
camera assembly of this invention;
[0015] FIG. 1B is a vertical cross-section of the embodiment
illustrated in FIG. 1A taken along line A-A;
[0016] FIG. 2A shows an external view of a second embodiment of a
camera assembly of this invention;
[0017] FIG. 2B is a vertical cross-section of the embodiment
illustrated in FIG. 2A taken along line A-A;
[0018] FIG. 2C is a bottom view of the embodiment of the invention
illustrated in FIGS. 2A and 2B;
[0019] FIG. 2D is a top view of the embodiment illustrated in FIG.
2A;
[0020] FIG. 2E is a vertical cross-section similar to FIG. 2B and
showing an alternative embodiment of the invention;
[0021] FIG. 3A shows an external view of a third embodiment of a
camera assembly of this invention;
[0022] FIG. 3B is a vertical cross-section of the embodiment
illustrated in FIG. 3A taken along line A-A;
[0023] FIG. 4A shows an external view of a fourth embodiment of a
camera assembly of this invention;
[0024] FIG. 4B is a bottom view of the embodiment of FIG. 4A;
[0025] FIG. 4C is vertical offset cross-section of the embodiment
of FIG. 4B taken along the line C-C;
[0026] FIG. 4D is a sectional view taken along line F-F of FIG.
4A;
[0027] FIG. 4E is a sectional view of an alternative embodiment of
the invention illustrated in FIG. 4A;
[0028] FIG. 5A is a vertical cross-section of a fifth embodiment of
the a camera assembly of this invention; and
[0029] FIG. 5B is a top cross-section of the embodiment illustrated
in Fig. SA.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] With reference to FIGS. 1A and 1B, there is illustrated a
camera assembly 10 which comprises a mounting cap 140 attached to
sidewalls 126 which are in turn attached to an optical surface 135
to form a camera housing 130 which surrounds a camera or lens
assembly, not shown, all as is well known in the art. Attached to
the camera housing 130 is an environmental shroud 190 which is
effective to deflect heat energy, dissipate heat energy not
reflected, protect the camera from water and/or other moisture, and
enables a high level of heat dissipation even when the camera is
operated in sunlight at high ambient temperature. According to a
first embodiment of the invention illustrated in FIG. 1A, a
two-piece environmental shroud 190 surrounds the camera housing 130
substantially completely and comprises a lower section 100 and an
upper section 120. The lower section 100 of the environmental
shroud provides the protection from radiant heat energy for the
camera housing 130 and may include a coating on a surface thereof
or the surface itself may be specified so that the emissivity is
such that it reflects or deflects most of the radiant heat energy
from the sun or any other hot body. Suitable coatings may include
______ polyester, polyurethane, epoxy, transparent metallized
polycarbonate coatings, aluminum foil inside various transparent
materials, galvanized steel, powder coatings, etc.
[0031] The shroud also includes means to remove heat either
absorbed from radiated heat energy or convected from the camera
housing 130 through a vent 105 included in the top of the lower
section 100. The upper section 120 of the environmental shield
covers the vent 105 in the lower section 100. The lower edge 125 of
the upper section is below the vent 105, thus providing a tortuous
path that prevents water from penetrating and adhering to the
camera housing 130. Instead the water is lead away from the housing
via the environmental shroud to a drip edge 108 from which water,
rain, melted snow, or other moisture will run off the environmental
shroud. This configuration prevents water from adhering to the
optical surface 135 and impairing optical performance. In a
preferred version of this embodiment, a ridge or a valley 103 is
formed in front of the vent 105 to further assist in preventing the
egress of water or other moisture into the vent. This is
particularly preferred when the difference in height between the
lower edge 125 of the top portion 120 and the vent 105 is not great
enough to establish a tortuous path which prevents water
penetration of the camera housing 130.
[0032] The embodiment of the invention illustrated in FIGS. 3A and
3B is substantially the same as the FIG. 1 embodiment described
above except that it of a one-piece construction. Thus the
environmental shroud embodiment of this figure achieves the same
function as that achieved by the FIG. 1A embodiment except that it
is a one piece design. The single piece of the environmental shroud
390 prevents water from entering the cavity between the shroud and
the camera housing, protects the camera housing from radiant heat
energy, and provides a drip edge 308 to prevent water from running
on to the optical surface 135. Louvres 305 are located on the sides
near the top let the hot air escape and also provide protection
from rain penetrating and adhering to the camera housing 330 and
impairing the optical surface 135.
[0033] In the embodiment of the invention illustrated in FIGS. 2A,
2B, and 2C, the environmental shroud 290 achieves the same function
as shroud 190 illustrated in FIG. 1A but has a different mode of
operation. Shroud 290 is a two piece design having an inner shroud
220 and an outer shroud 200 where the outer shroud 200 performs
multiple functions. The outer shroud 200 provides protection for
the camera housing 230 by reflecting and removing radiant heat
energy. It prevents rain from penetrating the camera housing 230.
The outer shroud 200 also provides the means of preventing water
from adhering to the optical surface 135 by providing a drip edge
208. The outer shroud 200 has vents 205 in a top portion that not
only allow hot air to escape, but also allow the water to penetrate
inside the outer shroud 200. The inner shroud 220 then collects the
water that penetrates the vent 205 and redirects it along the
inside surface 202 of the outer shroud 200 through water channels
225 located on the inner shroud 220. The inner shroud also has
vents 228 in the top that let the hot air escape. These vents are
above and/or offset to the vents 205 in the outer shroud 200. Thus,
the water does not penetrate the inner shroud 220 and does not
adhere to the camera housing 230 and impair the optical surface
135.
[0034] In an alternative embodiment illustrated in FIG. 2E, at
least a pair of bimetallic strips 241 are positioned over or under
the vents 205. These strips are actuated to close the vents when
the temperature falls below a certain level such that warm air
cannot escape from the assembly during colder weather. These strips
also provide insulation to keep the contents of the camera housing
130 from dropping below a certain temperature level. It will be
understood that such bimetallic strips may be used in combination
with any embodiment of the invention that includes vents and
function as described above. It will also be understood that vents
may be included in any embodiment of the invention including the
embodiments described in FIGS. 4A-5B below.
[0035] With reference to FIGS. 4 and 5, the embodiments illustrated
therein are different from the embodiments discussed and
illustrated in the preceding figures in several aspects. First,
these environmental shrouds do not present a largely smooth surface
appearance. This is to promote enhanced convection heat transfer
from a larger portion of the surface of the housing than is
obtained by the natural convection to produce a lower internal
housing temperature at the maximum ambient temperature. These
embodiments also avoid a large cavity in which insects or other
pests might be likely to take up residence. Secondly, these
embodiments are of modular construction which allows for smaller
tooling and part shipping volume prior to assembly. As will be
seen, the overall outer profile need not be a "bell" or domed shape
and allows for a the multi-piece construction that "wraps" around
the housing to give design appearance alternatives. Thirdly, since
convection plays a larger heat transfer role than conduction, the
various parts of these embodiments may preferably be constructed of
weather-resistant non-metallic materials, resulting in considerable
cost savings.
[0036] With reference to FIG. 4, there is illustrated a modified
aero-foil environmental shroud 490, which, like the previous
embodiments, has no moving parts. As illustrated in FIGS. 4A and
4B, a camera assembly 40 has a camera housing 430 having a mounting
cap 440 attached to sidewalls 426 which are attached to an optical
surface 135. As best seen in FIGS. 4B and 4D, two rings of vertical
strips 441 and 445 are placed concentric with the housing 430. The
inner ring of strips 441 is placed at some distance from the
housing 430, and the outer ring of strips 445 at some distance from
the inner ring of strips 441, such that air can circulate between
all three, i.e. in the gaps between 430, 441 and 445. The inner
strips 441 are positioned at the gaps (x) between the outer strips
445 so an air stream 413 traveling to the housing surface 430 must
turn and flow tangentially for some distance after radially
entering the outer gap (x). Therefore precipitation moisture
entering radially through the outer gap (x) will strike the inner
strips 441 and drain downward without reaching the camera housing
430 or the optical dome surface 135.
[0037] The strips 441 and 445 are secured at top and bottom by
structural cap 407, 408 and ring 409, 410 parts such that they
maintain their relative alignment. In addition, the mounting cap
piece 440 mates with the camera housing 430 to prevent water
ingress at the top of the environmental shield 490. In one
embodiment, the external vertical strips 445 are partial cylinder
shapes attached to the inside lip of a circular top cap 407 such
that the overall shape is cylindrical. The internal vertical strips
441 are also attached to the lip of another smaller circular cap
408 attached underneath the larger cap.
[0038] The internal strips 441 preferably have a central out-facing
vertical ridge profile 411 to direct the air stream behind the
external strips when wind impinges normal to the outer gap, and set
up a circulating venturi effect when the wind impinges normal to
the center of the external strip 445. In a variation thereof,
outwardly facing radial edges 412 on both sides of the inner strips
441 are turned to further prevent precipitation from blowing into
contact with the camera housing 430.
[0039] FIG. 5 illustrates an embodiment of the invention in which
the camera assembly 50 comprises an environmental shroud 590 which
is a modified turbine with moving parts. The shroud includes a
bearing 507 which is centrally positioned at the top of the camera
housing 530. This bearing is large enough to permit camera power
supply, video, and control wires (not shown) to pass through the
center bore. In the case of a ball bearing, the center race is
firmly attached to the camera housing 530. An example of a turbine
blade assembly 505 is illustrated in FIG. 5B.
[0040] The turbine blades 506 are attached firmly to the outer race
of the bearing 507 and is coupled to the camera housing 503 and the
mounting cap 540 via a coupling plate 504, thus forming a structure
that protects the bearing from the elements and prevents water
ingress at the top. The turbine blades 506 consist of strips of
metal that are formed into arcs and overlapped at an angle to the
radial direction such that they form vanes to catch the wind and
rotate the turbine regardless of the wind direction. Any wind
threatening to force precipitation into the gaps between blades
will also rotate the assembly, generating centrifugal force to push
the moisture away from the interior.
[0041] When no breeze is blowing, the gaps between the blades
provide significant area for natural convection. When a breeze is
blowing, the stirring action of the turbine blades will promote
forced convection at the camera housing surface, further increasing
heat transfer. In addition, as a result of this construction, heat
transfer conditions around the entire housing are very uniform. The
sun shining from one direction will not heat just one side, but the
heat will be distributed evenly.
[0042] In an alternative embodiment thereof, a continuous ridge or
depression running down the center of the blade is added to channel
moisture down to the bottom where a taper is provided for a drip
edge 508. A ring may be attached at the bottom circumference to
provide structural support and is also configured to facilitate the
movement of moisture away from the camera housing window 135.
[0043] The aesthetic appearance of the moving turbine blades can be
modified as desired. For example, strips similar to those
illustrated in the FIG. 4 embodiment may be attached over the
blades to minimize this effect. In this instance, with no wind, the
area available for natural convection is somewhat decreased and
when the breeze is blowing, less energy will reach the vanes to
turn the turbine assembly. However, the blades will be protected
from damage and will be effective to remove heat and protect the
camera housing as contemplated herein. It is also contemplated that
other combinations of the FIG. 4 and FIG. 5 embodiments may be
realized. For example, inner and outer vertical strips may be
employed to partially or completely cover the turbine blades.
[0044] While the invention has been described for convenience in
the context of an environmental shroud for a camera assembly, and
particularly when used to protect outdoor surveillance cameras, it
will be understood that the invention is not limited to these
embodiments. The environmental shrouds of the invention may be used
in any context where it is necessary to protect the contents of a
housing from moisture and heat, for example enclosed lighting,
electronic equipment, other surveillance equipment such as
switches, multiplexers, etc. Additionally, the invention may be
embodied in other specific forms without departing from the spirit
and scope or essential characteristics thereof, the present
disclosed examples being only preferred embodiments thereof.
* * * * *