U.S. patent application number 11/793932 was filed with the patent office on 2008-03-27 for wiper device for dome.
This patent application is currently assigned to TANAKA MACHINE CO., LTD.. Invention is credited to Kenichi Tanaka.
Application Number | 20080072393 11/793932 |
Document ID | / |
Family ID | 36601539 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080072393 |
Kind Code |
A1 |
Tanaka; Kenichi |
March 27, 2008 |
Wiper Device for Dome
Abstract
A wiper device for dome for cleaning a spherical clear dome
window (2) arranged at the front of a housing comprises: a
semi-circularly arced wiper arm (3) having rotatable structures on
its both ends fitted to near the central axis of the spherical
clear dome window (2) of the housing; a blow structure (17) for
blowing a pressurized fluid formed inside of the wiper arm (3)
which is arranged at a predetermined distance from a curved surface
of the spherical clear dome window (2) without contacting with
clear dome window; and a driving means for rotating the wiper arm
(3) reciprocatingly as the pressurized fluid being introduced into
the wiper arm from the one end of the wiper arm. As a result, the
wiper device for dome can clean the spherical clear dome window
arranged at the front of a housing for accommodating a TV camera, a
video camera or the like installed in a building without damaging
the spherical clear dome window.
Inventors: |
Tanaka; Kenichi; (Kanagawa,
JP) |
Correspondence
Address: |
JAMES C. WRAY
1493 CHAIN BRIDGE ROAD
SUITE 300
MCLEAN
VA
22101
US
|
Assignee: |
TANAKA MACHINE CO., LTD.
|
Family ID: |
36601539 |
Appl. No.: |
11/793932 |
Filed: |
November 28, 2005 |
PCT Filed: |
November 28, 2005 |
PCT NO: |
PCT/JP05/21789 |
371 Date: |
September 17, 2007 |
Current U.S.
Class: |
15/250.03 |
Current CPC
Class: |
A47L 1/02 20130101; B08B
5/02 20130101; B08B 3/024 20130101 |
Class at
Publication: |
015/250.03 |
International
Class: |
A47L 1/02 20060101
A47L001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 24, 2004 |
JP |
2004-373185 |
May 26, 2005 |
JP |
2005-153887 |
Claims
1. A wiper device for dome for cleaning a spherical clear dome
window arranged at the front of a housing, said housing
accommodating: a camera, an image amplifying circuit, control
circuits constituted mainly by processors, a mechanical unit for
operating the camera, a driving unit for driving a wiper arm, a
pressurized fluid generating unit and a heating unit for heating
the pressurized fluid, said wipe device for dome comprising: a
semi-circularly arced wiper arm having a pressurized fluid passage
for circulating the pressurized fluid and rotatable structures on
its both ends fitted to near the central axis of said spherical
clear dome window of said housing; a blow structure for blowing a
pressurized fluid formed inside of said wiper arm which is arranged
at a predetermined distance from a curved surface of said spherical
clear dome window without contacting with said clear dome window,
wherein: the pressurized fluid is introduced into said wiper arm
from the one end of said wiper arm; and the introduced pressurized
fluid is blown from said blow structure against the curved surface
of said clear dome window as said wiper arm being rotated
reciprocatingly.
2. The wiper device for dome according to claim 1, wherein: said
wiper arm is rotated along the curved surface of said clear dome
window reciprocatingly; the pressurized fluid is blown from the
inside of said wiper arm against said clear dome window from a time
when said rotating wiper arm is positioned at one end of said clear
dome window to a time when said rotating wiper arm reaches a center
of said clear dome window; the pressurized fluid is stopped blowing
from said wiper arm from the time when said rotating wiper arm is
positioned at the center of said clear dome window to a time when
said rotating wiper arm reaches the other end of said clear dome
window; and the pressurized fluid is blown again from said wiper
arm from the time when said rotating wiper arm is positioned at the
other end of said clear dome window to a time when said rotating
wiper arm reaches the center of said clear dome window.
3. The wiper device for dome according to claim 1, wherein: said
blow structure is formed as a plurality of blow holes for blowing
the pressurized fluid formed inside of said wiper arm and said blow
holes are arranged such that a diameter of said blow hole is
increased as said blow hole is formed farther apart from the one
end where the pressurized fluid is introduced so as to equalize
pressures of blown fluid from respective said blow holes against
said clear dome window.
4. The wiper device for dome according to claim 1: said blow
structure is formed as a continuous slit or discontinuous slits
inside of said wiper arm extending from the one end where the
pressurized fluid is introduced to the other end.
5. The wiper device for dome according to claim 1, wherein: said
driving means which rotates said wiper arm reciprocatingly is
automatically operated at predetermined times in 24 hours in order
to remove dirt stuck to said clear dome window.
6. The wiper device for dome according to claim 1, wherein: said
driving means which rotates said wiper arm reciprocatingly
comprises a luminosity sensor; and said driving means automatically
drives said wiper arm at a predetermined luminosity measured by
said luminosity sensor in 24 hours in order to remove dirt stuck to
said clear dome window.
7. The wiper device for dome according to claim 1, wherein: a
pressurized gas or a pressurized liquid is employed as the
pressurized fluid; and the pressurized gas and the pressurized
liquid can be blown alternatively such that the pressurized gas is
switched to the pressurized liquid or vice versa.
8. The wiper device for dome according to claim 1, wherein: a
pulverized mixture of gas and liquid is employed as the pressurized
fluid blown from said blow hole.
9. The wiper for dome device according to claim 1, wherein: the
pressurized fluid heated by a heater is blown from said blow hole
as the hot pressurized fluid.
Description
FIELD OF INVENTION
[0001] The present invention relates to a wiper device for cleaning
a clear dome window formed at the front of a housing which
accommodates TV cameras, video cameras or the like, particularly
relates to a wiper device for dome of a housing having spherical
clear dome window.
RELATED BACKGROUND ARTS
[0002] Wiper devices, which employ rubber wipers, for cleaning the
clear dome window of such housing have been known (for example, see
Japanese laid open patent Nos. 10-216049 and 10-216666).
[0003] A surveillance camera system, which accommodates a camera, a
camera controlling circuit, an image amplifying circuit, a power
supply circuit, mechanical units and other electronic circuits
necessary for surveillance in its housing having a spherical clear
dome window, is placed outdoors, particularly placed along the
road, so that dirt is sticking to a surface of the clear dome
window, through which image is acquired by the camera, with the
passage of time or drips of water stick to the surface when it
rains. In order to clean the clear dome window by rubbing the dirt
or the drips off the surface, a wiper device comprising a rubber
blade attached to a wiper arm is operated by the following
successive operational steps. A motor is rotated so that a motor
gear is rotated. The motor gear rotates the wiper arm together with
the rubber blade, which sweeps the surface of the clear dome
window. As a result, clear images can be acquired by the camera
through the cleared window.
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0004] However, in the above-mentioned conventional wiper device,
since a wiper element is directly attached to and cleans the clear
dome window by rubbing the window, scratches are formed on the
surface of the clear dome window. Once dirt gets in these
scratches, it is difficult to remove the dirt by the wiper element
completely. The clear dome window becomes clear temporally only
after the wiper device is operated. However, the dirt or worn
elements of the wiper device cause troubles, when the wiper device
is operated for a long time.
[0005] Some cleaning methods, in which a pressurized air is blown
from the periphery of a dome, are proposed. However, these methods
are not so effective to remove dirt and drips of rain.
[0006] In order to solve problems mentioned above, the present
invention proposes a wiper device for dome which can remove dirt or
drops of rain stuck to a clear dome window without contacting with
the window by blowing a compressed fluid such as air, water and the
like in a continuous or discontinuous slits or series of aligned
blow holes formed in a wiper arm, which is rotated around the clear
dome window without contacting the window.
Means to Solve the Problems
[0007] The above-mentioned problems are solved by devices specified
as follows. [0008] (1) A wiper device for dome for cleaning a
spherical clear dome window arranged at the front of a housing
comprising: a semi-circularly arced wiper arm having rotatable
structures on its both ends fitted to near the central axis of the
spherical clear dome window of the housing; a blow structure for
blowing a pressurized fluid formed inside of the wiper arm which is
arranged at a predetermined distance from a curved surface of the
spherical clear dome window without contacting with the clear dome
window; and a driving means for rotating the wiper arm
reciprocatingly as the pressurized fluid being introduced into the
wiper arm from the one end of said wiper arm. [0009] (2) The wiper
device for dome according to (1), wherein: the wiper arm is rotated
along the curved surface of the clear dome window reciprocatingly;
the pressurized fluid is blown from the inside of the wiper arm
against the clear dome window from a time when the rotating wiper
arm is positioned at one end of the clear dome window to a time
when the rotating wiper arm reaches a center of the clear dome
window; the pressurized fluid is stopped blowing from the wiper arm
from the time when the rotating wiper arm is positioned at the
center of the clear dome window to a time when the rotating wiper
arm reaches the other end of the clear dome window; the pressurized
fluid is blown again from the wiper arm from the time when the
rotating wiper arm is positioned at the other end of the clear dome
window to a time when the rotating wiper arm reaches the center of
said clear dome window. [0010] (3) The wiper device for dome
according to (1), wherein: the blow structure is formed as a
plurality of blow holes for blowing the pressurized fluid formed
inside of the wiper arm and the blow holes are arranged such that a
diameter of the blow hole is increased as the blow hole is formed
farther apart from the one end where the pressurized fluid is
introduced so as to equalize pressures of blown fluid from
respective the blow holes against the clear dome window. [0011] (4)
The wiper device for dome according to (1) or (2): the blow
structure is formed as a continuous slit or discontinuous slits
inside of the wiper arm extending from the one end where the
pressurized fluid is introduced to the other end. [0012] (5) The
wiper device for dome according to (1), wherein: the driving means
which rotates said wiper arm reciprocatingly is automatically
operated at predetermined times in 24 hours in order to remove dirt
stuck to the clear dome window. [0013] (6) The wiper device for
dome according to (1), wherein: the driving means which rotates the
wiper arm reciprocatingly comprises a luminosity sensor; and the
driving means automatically drives the wiper arm at a predetermined
luminosity measured by the luminosity sensor in 24 hours in order
to remove dirt stuck to the clear dome window. [0014] (7) The wiper
device for dome according to any one of (1) to (4), wherein: a
pressurized gas or a pressurized liquid is employed as the
pressurized fluid; and the pressurized gas and the pressurized
liquid can be blown alternatively such that the pressurized gas is
switched to the pressurized liquid or vice versa. [0015] (8) The
wiper device for dome according to any one of (1) to (4), wherein:
a pulverized mixture of gas and liquid is employed as the
pressurized fluid blown from the blow hole. [0016] (9) The wiper
for dome device according to any one of (1) to (4), wherein: the
pressurized fluid heated by a heater is blown from the blow hole as
the hot pressurized fluid.
EFFECTS ATTAINED BY THE INVENTION
[0017] The present invention can provide the wiper device for the
dome which can remove dirt or drops of rain stuck to the clear dome
window for the surveillance camera constituted by spherically
formed glass or resin without contacting the window by blowing the
compressed fluid such as air, water and the like from continuous or
discontinuous slits, or series of aligned blow holes formed in the
wiper arm, which is rotated around the clear dome window without
contacting the window. Even if a dome-shaped surveillance camera is
arranged at a high position, the clear dome window of the
surveillance camera can be kept in a clear state by operating the
wiper device of the present invention. Further, even if the
surveillance camera is employed in a season or a place where much
dirt or many drops of rain are generated, the clear dome windows
can be kept clean by periodically rotating the wiper arm according
to the conditions of the season or the place. Thus image acquiring
performance of the surveillance camera is kept at a minimum
deterioration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is an explanatory front view showing a wiper device
for dome as an embodiment by the present invention.
[0019] FIG. 2 is a partially enlarged front view of the wiper
device shown in FIG. 1.
[0020] FIG. 3 is a right side view of the wiper device shown in
FIG. 1.
[0021] FIG. 4 is a left side view of the wiper device shown in FIG.
1.
[0022] FIG. 5 is a chart showing an operational sequence of the
wiper arm.
[0023] FIG. 6 illustrates straight developed views of the wiper arm
having a series of same sized blow holes: (a) is a front view; and
(b) is a side view.
[0024] FIG. 7 illustrates straight developed views of the wiper arm
having a series of different sized blow holes: (a) is a front view;
and (b) is a side view.
[0025] FIG. 8 is a diagram illustrating control circuits of the
wiper device by the present invention.
[0026] FIG. 9 is a chart showing a time-controlled operational
sequence of the wiper device.
[0027] FIG. 10 is a chart showing an operational sequence
controlled according to luminosity around the surveillance
camera.
[0028] FIG. 11 is a front view showing another embodiment of a
wiper device by the present invention.
[0029] FIG. 12 illustrates straight developed views of the wiper
arm having a slit-shaped blow hole: (a) is a front view; and (b) is
a side view.
[0030] FIG. 13 is a partial front view of a modified wiper arm from
the wiper arm shown in FIG. 12.
PREFERRED EMBODIMENT BY THE PRESENT INVENTION
[0031] Hereinafter the best modes of the present invention are
explained in detail based on the embodiments.
Embodiment
[0032] Hereinafter, the embodiment by the present invention is
explained as referring to FIGS. 1-4 and 8. In the present
embodiment, the wiper device is integrated into a housing of a
camera dome where a TV camera or a video camera is arranged.
[0033] FIG. 1 is the front view showing the wiper device for dome
integrated in a dome window. FIG. 2 is the partially enlarged front
view of the wiper device illustrating flows of compressed air blown
out of holes of the wiper arm in order to remove dirt stuck to the
clear dome window. FIG. 3 is the right side view of the wiper
device. FIG. 4 is the left side view of the wiper device. FIG. 8 is
the diagram illustrating the control circuits for controlling
driving means of the wiper device.
[0034] In the present embodiment, air is employed as a pressurized
fluid.
[0035] FIG. 8 illustrates an example of control circuits for
driving a wiper arm 3 and a compressor 6. When microswitch 12a or
12b is pushed by a pushing shaft 11 of the wiper arm 3, an
ON-signal is inputted into a digital signal conversion circuit 27
or 28. And an OFF-signal is generated, when the microswitch is not
pushed by the pushing shaft 11. The ON-signal and the OFF-signal
are inputted into a CPU 21 as converted digital signals. The CPU 21
outputs instructions to a motor driving circuit 20 for controlling
a motor 10 and to a compressor driving circuit 6b for controlling a
compressor 6.
[0036] A timer 22 and a memory 29 storing programs and operational
steps therein, are connected to the CPU 21.
[0037] As shown these drawings, a clear dome window 2 is arranged
at the front of a dome cover 1, so that the dome cover 1 and the
clear dome window 2 constitute a housing which protects camera, an
image amplifying circuit, control circuits constituted mainly by
processors, mechanical units for driving the camera and the
like.
[0038] At an inner side of a semi-circularly arced wiper arm 3, an
air passage 4 for guiding air having a circular arced surface
extending along a curved surface of the clear dome window 2 is
formed.
[0039] The wiper arm 3 is rotatably fitted to arm shafts 5a and 5b
arranged near a central axis of the clear dome window 2.
[0040] At one end of the wiper arm 3, an arm gear 7 is arranged and
engaged with a motor gear 9. The motor gear 9 is fixed to a motor
shaft 8 of a driving motor 10.
[0041] The pushing shaft 11 is fixed to the other end of the wiper
arm 3. The microswitches 12a and 12b are arranged at right and left
ends of a locus formed by the movement of the pushing shaft 11 when
the wiper arm 3 is rotated around the arm shafts 5a and 5b, so that
the microswitches are activated according to the movement of the
pushing shaft 11.
[0042] The compressor 6 is arranged in the dome cover 1 and
introduces compressed air to the air passage 4 via a pipe 6a. Then
the compressed air is blown from a plurality of blow holes 17
pierced through the air passage 14, so that pressurized air flows
15 are generated around the clear dome window 2 (see FIG. 2). As a
result, dirt 14 or drips 14a are removed by the pressurized air
flows 15.
[0043] Hereinafter, operational steps of the wiper device
constituted in the above-mentioned way are explained as referring
to FIGS. 1-5 and 8.
[0044] As shown in FIG. 3, when the driving motor 10 rotates
counterclockwise, the motor gear 9 is rotated in the same
direction. As the rotating movement of the driving motor 10, the
arm gear 7 as well as the wiper arm 3 are rotated clockwise (but
the arm gear 7 is rotated counterclockwise when observed in the
opposite side as shown in FIG. 4).
[0045] The compressed air is introduced from the compressor 6 via
the pipe 6a to the air passage 4 formed inside of the wiper arm 3,
so that the dirt 14 and the drips 14a from rain are removed from
the whole spherical surface of the clear dome window 2, when the
wiper arm 3 is rotated around the clear dome window 2.
[0046] When the wiper arm 3 is rotated around the clear dome window
2 about a half turn from position 3a via position 3b to position 3c
as shown in FIG. 4, the microswitch 12a at the left side in FIG. 4
is pushed by the pushing shaft 11, so that the ON-signal from the
microswitch 12a is converted to a 4 bit or 8 bit digital signal by
the digital signal converting circuit 27 as shown in FIG. 8. The
converted digital signal is inputted into the CPU 21. The CPU 21
transmits an instruction to the motor driving circuit 20 so as to
rotate the motor 10 in the reverse direction. Consequently, the
wiper arm 3 is rotated in the reverse direction around the clear
dome window 2 from position 3c via position 3b to position 3a, so
that the microswitch 12b at the right side is pushed by the pushing
shaft 11. The pushed microswitch 12b outputs ON-signal and
succeeding steps are carried out in the same way mentioned above,
so that finally the motor 10 is rotated in the reverse direction to
the present direction.
[0047] While the wiper arm 3 is rotated around the clear dome
window 2 in the above-mentioned way, the pressurized air flows 15
from the plurality of the blow holes 17 formed in the air passage 4
blow against the spherical surface of the clear dome window 2
without interruption, so that the clear dome window 2 is kept clean
without contacting the wiper arm 2.
[0048] Hereinafter methods for controlling the pressurized air
flows 15, which are blown from the blow holes 17 and blown against
the clear dome window 2, are explained as referring to FIGS. 2, 4,
5 and 8.
[0049] As shown in FIG. 4, while the wiper arm 3 is rotated from
position 3b to position 3c, since the air from the blow holes 17 of
the air passage 4 formed inside of the wiper arm 3 is blown upward,
sometimes the dirt 14 is removed not so effectively. In order to
solve this disadvantage, the following measure is taken. A time
interval between a time when the wiper arm 3 is at position 3a
(microswitch 12b is on) and a time when the wiper arm 3 is at
position 3c (microswitch 12a is on) is measured by the CPU 21 and
is set "h", while the wiper arm 3 is rotated from position 3a to
position 3c, or vice versa Since the motor 10 is rotated at a
constant angular velocity, a time interval between a time when the
wiper arm 3 is at position 3a (or 3c) and a time when the wiper arm
is at position 3b can be set 1/2 h and is stored in the memory
29.
[0050] Then as shown in FIG. 5, instructions to operate compressor
6 in the CPU 21 are set as follows. While the wiper arm 3 is
rotated downward (namely a time interval 3a-b from position 3a to
position 3b or a time interval 3c-b from position 3c to position
3b), instructions are set "ON", so that the air flows 15 are blown
against the clear dome window 2. On the other hand, while the wiper
arm 3 is rotated upward (namely a time interval 3b-c from position
3b to position 3c or a time interval 3b-a from position 3b to
position 3a), instructions are set "OFF", so that the compressor 6
is stopped.
[0051] Since usually the surveillance camera is arranged at the
ceiling such that the clear dome window 2 is facing the ground or
the floor, operations of the wiper arm are set in the
above-mentioned manners. Namely, while the wiper arm 3 is rotated
from position 3a to position 3b, the wiper device is activated to
remove the dirt 14 and the drips 14a downwardly. On the other hand
while the wiper arm 3 is rotated upwardly from position 3b to
position 3a, the pressurized air flows 15 are stopped from being
blown against the clear dome window 2, since efficiencies for
removing the dirt 14 and drips 14a are not so effective. Thus on
the whole, the clear dome window 2 can be cleaned effectively.
[0052] Hereinafter methods how to equalize blowing amounts of air
are explained as referring to FIGS. 6 and 7.
[0053] Actually the compressor 6 introduces compressed air to the
curved air passage 4 via the pipe 6a as shown in FIG. 1, here,
however, the air passage 4 is considered to be developed as a
straight passage for easier explanation.
[0054] If diameters of the blow holes 17 formed in the air passage
4 are the same, blowing amounts of air flows 15 from the respective
blow holes 17 are not equal due to internal frictions of the air in
the air passage 4. The blowing amounts from the respective blow
holes in order are as follows: 16a>16b>16c>16d>16n.
[0055] Since differences in blowing pressures of the respective
pressurized air flows 15 fluctuate cleaning effects on respective
positions blown by the air flows 15 in the clear dome window 2,
blowing amounts of the air flows are varied according to degrees of
the blowing pressure as shown FIG. 7. Namely, diameters of blow
holes 19a, 19b, 19c, 19d and 19n are formed such that a diameter of
blow hole at lower blowing pressure is set larger than that at a
higher blowing pressure, so that respective blowing amounts 18a,
18b, 18c, 18d and 18n are set almost equal.
[0056] As explained above, the pressurized air flows 15 from the
blow holes 17 arranged the air passage 4 of the wiper arm 3 are
blown against the spherical surface of the clear dome window 2, so
that the dirt 14 and drips 14a can be removed effectively, since
the blowing air flows 15 are equally controlled.
[0057] Hereinafter, periodical cleaning sequences are explained as
referring to FIGS. 8 and 9. According to the cleaning sequences,
the clear dome window 2 is cleaned periodically in order to prevent
image acquiring effects of the camera from deteriorating by
suppressing the dirt 14 and drips 14 from sticking to the clear
dome window permanently. According to signals from a timer 22, the
CPU 21 transmits instructions to the motor driving circuit 20 so as
to rotate the wiper arm 3 periodically.
[0058] For example, time 25a to start cleaning the clear window 2
is set such that the CPU 21 transmits signals to the motor driving
circuit 20 and compressor driving circuit 6b at time 25a so as to
rotate the wiper arm 3 and so as to operate the compressor 6.
[0059] If the surveillance camera is placed in an environment where
the dirt 14 and drips 14a are generated heavily, another time 25b
can be set, or a time interval to start cleaning the clear window
can be set shorter, for example twice or more in 24 hours.
[0060] Thus the clear dome window 2 can be kept always clean.
[0061] As shown in FIG. 8, a luminosity sensor 23 can be arranged
in the clear dome window 2 so as to detect luminosity therein. When
luminosity varies as a curve 26c depicted in FIG. 10, signals
measured by the luminosity sensor 23 are converted by a digital
signal converter 24 and inputted into the CPU 21. If a luminosity
level to operate the wiper device is set 25c in the CPU 21, the
wiper arm 3 can be rotated automatically at point 26a and point
26b.
[0062] The wiper arm 3 can be rotated at lowest luminosity level or
at highest luminosity level by programs installed in the CPU 21 or
by one of signals of the surveillance camera.
[0063] As explained above, operations to rotate the wiper arm 3
automatically can be set at a highest or a lowest luminosity level
according to luminosity changes in the clear dome window, so that
the clear dome window 2 is always kept clean, in other words an
image acquiring performance of the surveillance camera is not
deteriorated.
[0064] In the above-explained embodiment, it is anticipated that
dirt and drips at some portions of the clear dome window can not be
removed completely due to a pressure difference between two
neighboring blow holes, since the pressurized air is blown from a
series of individual blow holes of the wiper arm as the wiper arm
being rotated reciprocatingly, so that clear images can not be
acquired by the camera.
[0065] In order to eliminate such pressure difference, slits are
formed in the air passage of the wiper arm 3 instead of plurality
of blow holes. A continuous slit 17A is formed on an air passage 4c
as shown in FIG. 12. A slit 17B discontinued by a connecting point
x can be formed on an air passage 4d as shown FIG. 13. By employing
such slits formed on the wiper arm 3 from which pressurized fluid
such as air, water or the like is blown as the wiper arm 3 is
rotated reciprocatingly over the clear dome, a wiper device for
dome which is capable of removing dirt and drips completely can be
proposed, so that clear images are always provided. The connecting
point x of the slit 17B reinforces the semi-circularly arced wiper
arm 3.
[0066] In the above explained examples, the wiper arm is combined
integrally with the clear dome window as well as the dome cover. As
shown in FIG. 11, however, a wiper device can be attached to the
dome cover 1.
[0067] In this embodiment, attaching portions 30, 30 are formed on
both sides of the dome cover 1. Adapting elements 31, 31 rotatably
supporting the wiper arm 3 are fixed to the attaching portions 30,
30 by screws or the like. Electric/electronic unit P for driving
and controlling the wiper device is attached to one of the adapting
element 31, and a small tank Q for storing pressurized fluid is
attached to the other adapting element 31 from where a pipe is led
to a compressor arranged outside. Thus the wiper device for dome
can be easily assembled.
[0068] In the tank Q a heater H for heating the pressurized fluid
can be arranged in order to remove stuck ice or snow to the clear
dome window by blowing heated fluid from blow holes 17, slit 17A or
slit 17B, so that the clear dome window is kept clean without any
fogginess.
[0069] As explained above, even if the wiper devices by the present
invention are employed in surveillance cameras arranged outdoor or
indoors at such high positions where scaffolds are required for
maintaining the surveillance cameras, the clear dome windows can be
cleaned automatically and can be kept always clean by remote
controls or programs installed in the CPU 21.
[0070] Since pressurized fluid is supplied from the vicinity of the
clear dome windows, a high pressure is not required so that a small
sized compressor is enough for the wiper device by the present
invention. Further since the wiper arm by the present invention
does not contact with the clear dome window directly, the clear
dome window is cleaned without generating any scratches on its
surface, which is one of the important features of the present
invention. Further, blowing positions, blowing cycles, blowing
timings depending on luminosity and the like can be installed in
the CPU 21 in accordance with environmental conditions around the
wiper device.
[0071] The wiper device can be operated at any time whenever it
rains or much amount of dirt is formed, according to instructions
from the CPU 21 in a controlling system of the surveillance
camera.
[0072] In the embodiments explained above, pressurized air is
employed as pressurized fluid, but pressurized liquid such as
water, pulverized liquid or the like can be also employed. When the
clear dome window is heavily contaminated, pressurized liquid can
be used together with pressurized air. At first dirt stuck to the
surface is removed by pressurized liquid and the surface is cleaned
by pressurized air afterwards.
[0073] In this case, a unit to switch pressurized air to
pressurized liquid or vice versa is required or respective units to
supply pressurized air and pressurized liquid are required.
* * * * *