CA2484692A1

CA2484692A1 - Light shutter device

Info

Publication number: CA2484692A1
Application number: CA002484692A
Authority: CA
Inventors: Robert Paquet; Gaetan Robitaille; Gerald Canuel; Remi Paquet
Original assignee: Individual
Current assignee: LES ENTREPRISES ROPAQ Inc
Priority date: 2003-10-14
Filing date: 2004-10-14
Publication date: 2005-04-14

Abstract

The present invention is directed to a light shutter device for blocking fight of a light source which emits the light into a path of light. The shutter device is particularly adapted for use with high intensity discharge lamps such as metal halide lamps. The shutter device is provided with a support frame extending in front of the light source.
The shutter device also has a first and a second sliding plate slidably mounted in the support frame. The plates are slidably actuatable between an open position wherein the plates extend around the light source without interfering with the path of light and a closed position wherein the plates extend one against the other in the path of light for obstructing the path of light, thereby blocking the light of the light source. The shutter device also comprises actuating means for slidably actuating the sliding plates in each position.

Description

LIGHT SHUTTER DEVICE
FIELD OF THE INVENTION
The present invention generally relates to a light shutter device for use with lighting sources and, more particularly, it concerns a light shutter device specifically adapted for use with high intensity discharge (HID) lamps.
z o EACKGROUND OF THE INVENTION
High intensity discharge lamps such as metal halide light sources are widely used for many years for lighting indoor and outdoor environments such as arenas, stadiums or gymnasiums for example. Such light sources are also often used in TV
broadcast studios and in theatres.
It is well known in the art that most conventional high intensity discharge (HID) lamps cannot be instantly turned on to full brightness and intensity.
Likewise, such lamps cannot be turned off and then quickly turned on again to full intensity.
These lamps use ballasts which require to cool down before being turned on again.
When power is removed from an operating metal halide lamp, it requires approximately fifteen minutes to re-strike, using normal voltages, and an additional five minutes to reach a stable color temperature and light output.
Incandescent lamps do not have such a re-strike problem. Special types of arc lamps, called instant re-strike arc lamps, are available but they are very expensive.
Additionally, instant re-strike arc lamps do turn on quickly after they have been turned off, however, if shut off for more than a few minutes, they may re-light at a different temperature or color that what is preferred or needed.
HID lamps are desirable for many uses because the type (color, intensity) of output and the economy of such lamps. This is specially true for lighting of large areas where the light must be controlled and concentrated for projection over substantial distances.
The re-strike problem, as previously stated, is widely recognized in the art.
s Attempts have been made to deal with that situation and allow relatively quick onloff control. One such attempt utilizes a dimming circuitry to reduce the current to the arc tamp. This reduces the brightness or intensity but does not extinguish the light so complete darkness cannot be achieved.
1 o Therefore, shutter mechanisms have been devised for oflowing a fast turn offl turn on of this type of light sources without requiring a real shut down thereof.
Indeed, these types of mechanisms leave the light at full power but block the fight.
Primary problems with this approach include the heat buildup that occurs when blocking such high intensity lights, and difficulty in sealing off the light to achieve total 1 s blockage of light.
For example, already available on the market is a louver-based shutter that is mechanically operated for blocking off light. Such a louver-based shutter is mountable in front of a metal halide light source and louvers are operated for 2 o blocking off light emitted from the light source, thereby providing a black out environment. The time response of such device is about 2 seconds for a full range movement of the louvers. US patent No. 6,550,937 and US patent application No.
200310053314 describe such louver-based mechanisms. The major drawback of such mechanisms is that the louvers extend in the path of the light and cause 25 therefore depreciation in light levels.
Another mechanically operated shutter device presently used improves on the louver-like mechanisms with an array of fins that operates fateraily like a camera aperture. The major advantage of such kind of devices is that there is no loss of light 3 o when the shutter is fully opened. The time response of such device is about 0.8 second for a full aperture of the shutter. However, such devices become complex and expensive to manufacture, particularly for large lamps and when a heavy-duty mechanism is required.
Also known in the art, there is US patent No. 5,887,970 describing a shutter system for selectively blocking the path of light of a high intensity discharge lamp.
This shutter system comprises a high intensity discharge lamp, a high intensity discharge light housing into which the lamp is secured and a shutter and light absorption system secured to the light housing. The shutter and light absorption system has a light absorbing shutter screen, a screen moving system for moving the to screen in front of the lamp to block selectively the path of light and for withdrawing the screen from the path of light and a support system for the screen moving system.
The screen, when retracted, does not significantly interfere with the path of light of the system and, when fully extended, substantially blocks the path of light of the high intensity discharge lamp.
Also known in the art, there is US patent No. 6,168,291 disclosing a luminaire motorized shade or dourer mechanism including a lamp mounted within a reflector and a motorized shade unit that opens and closes in front of the lens of the reflector.
The shade unit includes a motor, two rollers, two guide cables, a sheet of opaque 2 o flexible material or fabric, and an aluminum frame. The motor drives the roller to run the shade in front of the lens to cover it and also to uncover. The motorized shade or douser mechanism is used to effectively block the light emitting from the lamp and create a condition whereas no light leaves the lens of the luminaire.
2 5 Even if the two above described systems correctly block the light, they do not provide heavy-duty and fast mechanisms supporting a high number of ONIOFF
operations.
Also known in the art, there is US patent No. 5,860,733 disclosing a lighting 3 o fixture with a controllable light block. The fixture includes a reflector and a high intensity discharge lamp. A cover member is mounted to the reflector and is moveable between an unblocked position and a blocked position. The apparatus is configured so that the cover member can be in the blocked position for indefinite periods of time even though the arc lamp continues to be operated at full power, without heat buildup which is detrimental to any part of the apparatus. fn this mechanism, the movement of the cover member is effectuated in at least 1.2 seconds. Such mechanism is however not well adapted for providing an easy installation on any existing metal halide light source.
Also available are metal halide fight sources provided with an integrated mechanical dual shutter system. The dual shutter system is provided with a lower to shutter rotatively closing over an upper shutter, thereby ensuring no forward light.
The two shutters work together through mechanical linkages to close at the same time. However, such dual shutter systems are integrated to the metal halide light sources and can not be easily installed on existing light sources. Moreover, since the two shutters are rotatively operated, dual shutters could not be conveniently used on large sources more particularly.
Also known in the art, there are the following IJ.S. patents which describe different lighting systems: IJ.S. patents Nos. 4,719,545; 5,034,866;
6,563,255;
6;575,577 and 6,588,912.
Therefore, it would be desirable to provide a more convenient light shutter device allowing to turn offl turn on a light source in a fast manner without requiring a real shut down of the light source. Moreover, it would also be desirable to provide such a light shutter device that would be easily installed on any existing metal halide 2s light source while providing an inexpensive and heavy-duty mechanism supporting more ONIOFF operations than existing devices.
StJIItIMARY OF THE 1NVENTiON
An object of the present invention is to provide a light shutter device that satisfies the above mentioned needs.

Accordingly, the present invention is directed to a light shutter device for blocking light of a light source which emits the light into a path of fight.
The light shutter device is provided with attaching means for attaching the light shutter device 5 in front of the light source. The light shutter device is also provided with a support frame attached to the attaching means and extending in front of the light source. The light shutter device also has a first and a second sliding plate slidably mounted in the support frame. The plates are slidably actuatable between an open position wherein the plates extend around the light source without interfering with the path of light and ~o a closed position wherein the plates extend one against the other in the path of light for obstructing the path of light, thereby blocking the light of the light source. The light shutter device is also provided with actuating means for slidably actuating the sliding plates in each of the open and closed positions.
In a preferred embodiment of the invention, each of the sliding plates has a lower and an upper crossing blade connected together. Each of the lower blades extends in a lower plane and is slid one against the other in the closed position. Each of the upper blades extends in an upper plane and is slid one against the other in the closed position, thereby providing an overlapping relationship between the first and 2 o second sliding plates in the closed position.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and advantages of the invention will become apparent upon reading the detailed description and upon referring to the drawings in which:
Figure 1 is a perspective view of a light shutter device in an open position mounted on a metal halide light source according to a preferred embodiment of the 3 o present invention.

Figure 2 is another perspective view of the light shutter of Figure 1 in an open position.
Figure 3 is an elevation perspective view of the light shutter of Figure 1 in an open position.
Figure 4 is an elevation perspective view of the light shutter of Figure 1 in a closed position.
Figure 5 is a perspective view of the light shutter of Figure 1 in a closed position.
Figure 6 is a top view of a light shutter device in an open position according to Zo a preferred embodiment of the present invention.
Figure 7 is a top view of the light shutter device of Figure 6 in a closed position.
Figure 8 is a top view of the sliding plates of the light shutter device of Figure 6.
15 Figure 9 is a top view of the sliding plates of Figure 8 in another position.
Figure 10A is a top view of a lower blade of a sliding plate of a light shutter device according to a preferred embodiment of the present invention.
Figure 10B is a side view of the lower blade of Figure 10A.
Figure 11A is a top view of an upper blade of a sliding plate of a light shutter 2 o device according to a preferred embodiment of the present invention.
Figure 11 B is a side view of the upper blade of Figure 11A.

Figure 12A is a front view of a slide of a light shutter device according to a preferred embodiment of the present invention.
Figure 12B is a top view of the slide of Figure 12A.
Figure 12C is a side view ~f the slide of Figure 12A.
s Figure 13A is a top view of an element of the support frame of a light shutter device according to a preferred embodiment of the present invention.
Figure 13B is a side view of the element of Figure 13A.
Figure 13C is a rear view of the element of Figure 13A.
Figure 13D is a front view of the element of Figure 13A.
~o While the invention will be described in conjunction with example embodiments, it wilt be understood that it is not intended to limit the scope of the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included as defined by the appended claims.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the following description, similar features in the drawings have been given similar reference numerals and in order to lighten the figures, some elements are not 2 o referred to in some figures if they were already identified in a preceding figure.
The present invention is directed to a light shutter device adapted to be easily mounted on any lighting sources, and more particularly on any existing high intensity discharge lamps such as metal halide light sources. As previously mentioned, metal halide light sources cannot be turned on again just after a turn off thereof.
Thus, the light shutter device of the present invention is devised for allowing an efficient blocking off of the light in a practical manner without requiring a real shut down of the light sources, In a preferred embodiment, the present light shutter device is able to open or close in 0.4 second, thereby providing an instantaneous ONIOFF, faster than any existing device.
The present shutter device is preferably pneumatically operated, as will be described hereinafter, for providing a heavy-duty mechanism supporting more ON/OFF operations than existing devices, thereby providing a longer lifetime of the 1 o shutter device.
Moreover, a great advantage of the present light shutter device is it can be easily mounted on existing light sources, merely in slightly modifying the hanging attaching means of the light sources.
Referring now to Figures 1 to 5, there is shown a light shutter device 1 for blocking light of a light source 3 which emits the light into a path of light.
As explained above, the present light shutter device 1 is particularly well adapted for use with high intensity discharge (HID) lamps. In the illustrated embodiments, the light shutter 2 o device 1 is mounted on such a high intensity discharge lamp, more specifically on a metal halide light source 3. However it should be understood that the present light shutter device 1 could also be conveniently used with other type of lamps.
Still with reference to Figures 1 to 5, the light shutter device 1 of the present invention is provided with attaching means 23 for attaching the light shutter device 1 in front of the light source 3. Preferably, as well known in the art, the light source 3 is provided with hanging attaching means for conveniently attaching the light source 3 to a support. In the illustrated embodiments, the light source 3 is attached to the ceiling but it should be understood that the lamp could also be attached to a vertical 3 o panel for example. Preferably, the attaching means 23 of the light shutter device is secured to the hanging attaching means of the light source 3. As illustrated, the attaching means 23 are preferably provided with a plurality of chains attached to the hanging attaching means of the light source 3 but obviously, any other convenient means for attaching the light shutter device 1 in front of the light source 3 could also be envisaged.
Referring now to Figures 6, 7 and again to Figure 1, the light shutter device of the present invention is also provided with a support frame 21 attached to the attaching means 23 and extending in front of the light source 3. As can be seen in Figure 1, the support frame 21 advantageously extends around the light source without interfering with the path of light. In other words, the support frame 21 extends to on both sides of the path of light in order not to generate any loss of light. Preferably, the support frame 21 is provided with a first and a second slide 5, 7, which are illustrated in Figures 12A to 12C. Also preferably, the support frame 21 also has two supporting elements 25, 27 attached to the slides 5, 7 for providing a practical assembly of the frame 21. Figures 13A to 13D illustrate such supporting elements 25, 27.
Referring again to Figures 1 to 5, the light shutter device 1 also has a first and a second sliding plate 9, 11 slidably mounted in the support frame 21.
Preferably, each of the sliding plates 9, 11 slides in the slides 5, 7 of the support frame 21. The 2 o sliding plates 9, 11 are slidabiy actuatable between an open position wherein the sliding plates 9, 11 extend around the light source 3 without interfering with the path of light, and a closed position wherein the sliding plates 9, 11 extend one against the other in the path of light for obstructing said path of light, thereby blocking the light of the light source 3. Figures 1 to 3 illustrate the light shutter device 1 in the open 2 s position while Figures 4 and 5 illustrate the light shutter device 1 in the closed position.
With reference to Figures 5 to 9 and still to Figure 1, each of the sliding plates 9, 11 advantageously has a lower 17, 19 and an upper crossing blade 13, 15.
The 3 o blades 13, 17 and respectively 15, 19 are connected together. Each of the lower blades 17, 19 extends in a lower plane while each of the upper blades 13, 15 extends in an upper plane. Figures 10A and 10B illustrate a lower blade 17 of a sliding plate 9 while Figures 11A and 11B illustrate an upper blade 13 of a sliding plate 9 of the shutter 1 of the present invention. As can be better appreciated in Figures 5 and 7, the blades 13, 15, 17, 19 are specially designed for allowing the sliding plates 9, 11 to be slid one against the other. Indeed, the upper blades 13, 15, s extending in the same upper plane, are slidable one against the other as the lower blades 17, 19, extending in the same lower plane, are slidable one against the other in an overlapping relationship, when the shutter 1 is in the closed position.
Figures 7 and 9 show the overlapping relationship of the sliding plates 9, 11 providing a very efficient light blocking off when the sliding plates 9, 11 are slid in the closed position.
Referring now to Figures 4 to 7, the light shutter device 1 is also provided with actuating means for slidably actuating the sliding plates 9, 11 in each of the open and closed positions. Preferably, the actuating means are pneumatic actuating means. Also preferably, the actuating means are provided with a first and a second pneumatic cylinder 29, 31, each of the cylinders 29, 31 respectively actuating one of the sliding plates 9 ,11. In the illustrated embodiments, the pneumatic cylinder 29 operates the sliding plate 9 while the pneumatic cylinder 31 operates the sliding plate 11. It is worth mentioning that each of the cylinders 29, 31 can be simultaneously or independently actuated, according to a particular application. In a preferred 2 o embodiment of the present invention, each of the pneumatic cylinders 29, 31 are advantageously provided with a pneumatic absorber (not shown) for reducing operating noise. The light shutter device 1 may also advantageously be provided with an automaton (not shown) operatively connected to the actuating means for controlling the actuating means. In this case, the pneumatic cylinders 29, 31 may 2 s advantageously be controlled with the automaton, thereby allowing blocking the light or not in a predetermined sequence. It is worth mentioning that the shutter device 1 may also be partially open if required by a particular application. In this case, the actuating means are particularly designed for providing a slidable actuation of the sliding plates 9, 11 in an intermediary position between the closed and open 3 o positions. Of course, a plurality of intermediary positions could also be envisaged. As can be seen in Figures 4 and 13A to 13D, each of the pneumatic cylinders 29, 31 are preferably supported in the support frame 21 with one of the supporting elements 25, 27 respectively. However, any other suitable means for supporting the cylinders 29, 31 in the frame 21 could also be envisaged.
Given the fact that light sources such as metal halide light sources radiate a great quantity of heat when operating, it is preferable the shutter device 1 be made of aluminum for avoiding torsion of the sliding plates 9, 11 or of the support frame 21.
Thus, the sliding plates 9, 11 are advantageously made of aluminum. The supporting frame 21 is also preferably made of aluminum, thereby providing a heavy-duty shutter device 1. Therefore, contrary to some of the prior art devices, the present to shutter device 1 do not require installation of fans to cool down the elements of the shutter device 1.
In another embodiment that is not illustrated, each of the sliding plates 9, may be provided with a heat resistant transparent colored plate which can be made is of glass or plastic. One can also envisaged to use a plurality of stacked colored guillotines which can be independently controlled for providing (fight effects.
Although preferred embodiments of the present invention have been described in detail herein and illustrated in the accompanying drawings, it is to be understood 2 o that the invention is not limited to these precise embodiments and that various changes and modifications may be effected therein without departing from the scope or spirit of the present invention.

Claims

1. ~A light shutter device for blocking light of a light source which emits said light into a path of light, said light shutter device comprising:
attaching means for attaching said light shutter device in front of said light source;
a support frame attached to said attaching means and extending in front of said light source;
a first and a second sliding plate slidably mounted in said support frame, said plates being slidably actuatable between an open position wherein said plates extend around said light source without interfering with the path of light and a closed position wherein said plates extend one against the other in said path of light for obstructing said path of fight, thereby blocking said light of said light source; and actuating means for slidably actuating said sliding plates in each of said open and closed positions.

2. ~The light shutter device according to claim 1, wherein each of said sliding plates comprises a lower and an upper crossing blade connected together, each of said lower blades extending in a lower plane and being slid one against the other in said closed position, each of said upper blades extending in an upper plane and being slid one against the other in said closed position, thereby providing an overlapping relationship between said first and second sliding plates in said closed position.

3. The light shutter device according to claim 1, wherein said support frame comprises a first and a second slide.

4. The light shutter device according to claim 1, wherein said support frame extend around said light source without interfering with the path of light.

5. The light shutter device according to claim 1, wherein said actuating means are pneumatic actuating means.

6. The light shutter device according to claim 1, wherein said actuating means comprise a first and a second pneumatic cylinder, each of said cylinders respectively actuating one of said sliding plates.

7. The light shutter device according to claim 6, wherein each of said pneumatic cylinders is provided with a pneumatic absorber for reducing operating noise.

8. The light shutter device according to claim 1, further comprising an automaton operatively connected to said actuating means for controlling said actuating means.

9. The light shutter device according to claim 1, wherein each of said sliding plates is made of aluminum.

10. The light shutter device according to claim 1, wherein each of said sliding plates comprises a heat resistant transparent colored plate.

11. The light shutter device according to claim 10, wherein said colored plate is made of glass.

12. The light shutter device according to claim 10, wherein said colored plate is made of plastic.

13. The light shutter device according to claim 1, wherein each of said sliding plates comprises a plurality of stacked heat resistant transparent colored plates, each of said colored plates being independently actuated for providing light effects.

14. The light shutter device according to claim 1, wherein said light source is a high intensity discharge lamp.

15. The light shutter device according to claim 1, wherein said light source is a metal halide light source.

16. The light shutter device according to claim 1, wherein said light source is provided with a hanging attaching means, the attaching means of said shutter device being secured to said hanging attaching means.

17. The fight shutter device according to claim 1, wherein said actuating means slidably actuate said plates in an intermediary position between said closed and open positions.

18. The fight shutter device according to claim 1, wherein said support frame extends around said light source without interfering with the path of light and comprises a first and a second slides, each of said sliding plates sliding in said slides and comprising a lower and an upper aluminum crossing blade connected together, each of said lower blades extending in a lower plane and being slid one against the other in said closed position, each of said upper blades extending in an upper plane and being slid one against the other in said closed position, thereby providing an overlapping relationship between said first and second sliding plates in said closed position, said actuating means comprising a first and a second pneumatic cylinders, each of said cylinders respectively actuating one of said sliding plates and being provided with a pneumatic absorber for reducing operating noise.