Illumination – Light source and modifier – Condition responsive
Reexamination Certificate
1998-11-16
2001-03-06
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Condition responsive
C362S276000, C362S802000, C362S376000, C362S265000, C362S119000, C324S332000
Reexamination Certificate
active
06196703
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a safety device for use with lighting fixtures. More specifically, the present invention provides a safety shutoff system for use with lighting fixtures which avoids dangerous situations that could cause fires.
As is well known, lighting bulbs tend to become very hot during use. Consequently, care must be taken to provide appropriate shielding from the heat. This is particularly true in lighting fixtures which utilize halogen lighting elements. Should flammable materials come close to, or in contact with these bulbs, a real fire danger is created. The consequences of such a fire would be catastrophic resulting in harm to property and even the risk of death.
Typically, shielding or protection from the heat created by lighting bulbs has been accomplished by providing appropriate lamp shades or lamp coverings so as to avoid contact between the bulb and other elements. Alternatively, shielding has been accomplished by providing a bulb enclosure which completely surrounds the light bulb itself thus avoiding any contact. This shielding or protection is not always effective as the shield itself tends to absorb heat. Care must then be taken to protect objects from contacting either the shield or the bulb, so as to avoid risk of fire.
Previous methods of shielding from the heat of the bulb have been ineffective for a number of additional reasons. From a lighting perspective, it is undesirable to place elements in front of the light bulbs. Obviously, these elements, despite their physical makeup, will absorb some light and reduce the amount of light provided. Additionally, the need for shields or shades drastically limits the design flexibility in developing the lighting system. In order to create a shield which appropriately protects the bulb, but does not itself become dangerously hot, a relatively large structure is necessary. Consequently, alternative protection methods are necessary whenever a fairly sleek and compact lighting fixture is desired. Also, shielding itself does not necessarily prevent the risk of fire but rather simply delays it. More specifically, the shield may simply prevent a product from igniting for some period of time but does not eliminate the risk. Lastly, the shield will not likely protect from objects of all sizes. Small objects may pass through a mesh shield, for example.
In attempting to avoid the risk of fire danger, the reduction or elimination of heat in the bulb itself is not a viable option. As is well known, it is necessary for the bulb to be as efficient as possible at producing usable light. With today's lighting technology, this requires the use of higher power levels which necessarily generate both light and heat.
As can be expected, any contact with objects which are even remotely flammable can be very dangerous. For example, any contact between the light bulb and draperies or fabrics can potentially cause eruption into flames. Consequently, this entire situation must be avoided. Further, an active approach to avoiding the risk of fire is more desirable as these lighting fixtures are typically unattended. For example, lights are occasionally left on and windows are occasionally left open. It is not uncommon for draperies to be blown close to or in contact with the lighting fixture. If active protection from this threat of fire is included within the fixture, a much safer situation is created.
Another potentially dangerous problem can occur when these high intensity lamps are free standing. Particularly, when perched atop a tall, narrow support structure. Very little contact may be required to tip the lamp over. If this occurs, the heat source could be placed proximate various flammable materials. In the first situation, as described above, the lamp will usually be placed in a safe location and a problem will only occur if some type of material unexpectedly comes close to the bulb. With the tipping problem, however, this initial cautious placement is of no benefit. The lamp could tip and even subsequently slide or roll. Thus, bringing the heat source near a wide variety of hazardous materials, which may be ignited even if remaining some distance from the bulb.
SUMMARY OF THE INVENTION
The present invention provides for a safety system which will automatically shut off the lighting system when foreign objects come dangerously close to the light element. For example, should the wind blow draperies dangerously close to the light, the system of the present invention will cause power to be removed, thus avoiding any further danger of flames.
The automatic shutoff operation of the present invention is accomplished using a plurality of infrared emitter and detector pairs to create a “sensor shield” which completely surrounds the lighting element. More specifically, infrared light beams are directed between each emitter/receiver pair. Related circuitry can then be used to determine if the infrared beam is being disrupted. By positioning multiple emitter/receiver pairs in appropriate locations, the infrared beams will completely surround the lighting element. Consequently, these emitter/receiver pairs are capable of sensing the presence of an object in close proximity to the lighting element. Further, once these objects are removed the control system of the present invention allows power to be reapplied to the lighting element. This allows full operation of the light so long as no objects are present adjacent to the lighting element while also providing a safety shutoff.
Since the bulb will emit radiation which may coincide with that from the emitter, a mechanism is provided that will be able to discriminate between signals sent from the emitter and signals sent by the bulb. Additionally, the characteristics of the bulb may be somewhat inconsistent. The frequency of signals emitted by the bulb may change over time and may not be consistent from one bulb to another. To deal with these complications, the emitter is driven by a timer chip to emit the signal at a predetermined frequency. A differential amplifier is connected to the receiver which “tunes” the receiver to be responsive only to signals at the predetermined frequency and to reject other signals produced by the bulb.
Another aspect of the present invention is the inclusion of a tilt switch mechanism which will cut off power to the lamp, if the lamp is moved from its normal operating position. This creates a second safety system in addition to the above referenced emitter/receiver shield. For example, if a normally vertical lamp is accidentally knocked over, the lamp, and hence, the switch will be in a horizontal position. Elements within the switch are sensitive to this orientation and thereby open the circuit, preventing power from reaching the bulb or other portions of the control circuitry.
It is an object of the present invention to provide a lighting system which itself avoids the risk of fire danger when objects come in close proximity to the lighting element. This is accomplished by providing active sensors which detect the presence of objects in close proximity to the light and consequently shut the light off.
It is an object of the present invention to provide a safety system which will cause a light bulb to automatically shut off when objects are detected in close proximity to the light itself. The safety system will be fast acting and efficient by using infrared light.
It is another object of the present invention to provide a detection system utilizing infrared receiver and emitter pairs which will surround the lighting element of a light fixture. Consequently, when the infrared beams connecting this emitter/receiver pair are broken by objects, the light fixture will automatically shut off. Consequently, the lighting element will not generate undesirable heat, thus eliminating the risk of fire.
It is a further object of the present invention to provide a lighting controller which will avoid the risk of fire hazard by automatically shutting off when foreign objects are detected in close proximity to the lighting element.
Camps Francis W.
Eusterbrock Paul W.
Holtkotter International, Inc.
Lervick Craig J.
O'Shea Sandra
Oppenheimer Wolff & Donnelly LLP
Ton Anabel M
LandOfFree
Automatic shutoff system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatic shutoff system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic shutoff system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2500959