Communications: electrical – Systems – Periodic or flashing
Reexamination Certificate
2000-11-09
2002-10-22
Hofbass, Jeffery (Department: 2632)
Communications: electrical
Systems
Periodic or flashing
C340S321000, C340S953000, C340S691300, C340S870030, C340S870030, C340S573100
Reexamination Certificate
active
06469619
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to an intrinsically-safe warning device for providing warning to personnel of an unsafe condition. More specifically, the present invention relates to an intrinsically-safe roof hazard warning device designed to be attached to the roof of a mine to indicate unsupported roof conditions or other unsafe conditions. The device of this invention is especially useful in underground mining operations.
BACKGROUND OF THE INVENTION
Underground mines potentially present many hazards to miners and other workers. Such hazards include, for example, confined spaces, falling rock or substrate from side walls and roof structures, potentially explosive atmospheres (e.g., methane and/or coal dust), heavy equipment, and the like. For example, during mining operations, roof bolts are used to support and maintain the stability of the roof system. Nonetheless, during expansion of such mining areas and perhaps at other times, the area beyond the last installed roof bolts or support systems remains unsupported and, thus, potentially unstable and hazardous. Miners or other personnel venturing (unknowingly or otherwise) into such unsupported areas (i.e., beyond the last row of roof bolts) are exposed to hazardous conditions associated with the potentially unstable roof structure. Moreover, during cutting into mine areas the risk of potentially explosive or hazardous conditions may be particularly high since the newly-opened mine shaft may intersect gas pockets or other concentrated gaseous areas or create high dust levels or may intersect areas with particularly weak overburden.
It would be desirable, therefor, to provide intrinsically-safe warning devices that render the attendant hazard associated with unsupported roof conditions or other hazards more evident. It would also be desirable to provide intrinsically-safe warning devices which direct a person's attention to read the appropriate warning message on the device and, therefore, make the person more likely to comply with the warning and avoid the hazard. It would also be desirable to provide intrinsically-safe warning devices which are inexpensive, self-contained, reliable, portable, easily installed, easily relocated, and easily removed. Such devices would be ideally suited for warning temporary or short-term hazardous conditions. The present invention provide such intrinsically safe warning devices. These devices represent an engineering intervention strategy especially adapted toward improving miners' ability to recognize and avoid the hazardous zone of unsupported mine roofs.
SUMMARY OF THE INVENTION
The present invention relates generally to an intrinsically-safe warning device for providing warning to personnel of an unsafe condition. More specifically, the present invention relates to an intrinsically-safe roof hazard warning device designed to be attached to the roof of a mine to indicate unsupported roof conditions or other unsafe conditions. The device of this invention is especially useful in underground mining operations in order to discourage miners from going into unsupported mine roof areas by rendering the attendant hazard more evident, directing the miner's attention to an appropriate warning message on the module, and thus avoiding the hazard beyond the device.
The warning device of this invention is intrinsically-safe, self-contained, simple to use, inexpensive to build and operate, portable, light weight, compact, and low-profile. These features make it especially useful as a warning device in short-term or temporary hazardous situations where the installation of complex and/or bulky warning systems may not be warranted or justified. Since the present warning device is intrinsically-safe, it can be used in a variety of mining environments (including gassy mining environments). By providing an inexpensive, readily portable, and easily installed (as well as easily removed) system, compliance will likely be significantly improved.
One object of the present invention is to provide an intrinsically-safe hazard alert module for warning personnel of a potential hazard, said module comprising (a) a case having side walls, a first end wall, and second end wall wherein the case has an internal cavity formed by the side walls and first and second end walls; (b) a low-voltage power supply within the case comprising one or more direct current batteries; (c) a switch in electrical contact with the low-voltage power supply to activate the module; (d) a light-emitting diode in electrical contact with the switch and the low-voltage power supply; and (e) a means to attach the module in close proximity to or in a hazard area having a potential hazard such that the light is directed towards the area from which personnel are likely to enter the hazard area; wherein the module is lightweight, portable, and intrinsically-safe; whereby, when the module is activated, the light-emitting diode emits a light to warn personnel in the area of the potential hazard and direct their attention to the potential hazard. The intrinsically-safe hazard alert module of this invention is especially adapted for use in mining applications such as, for example, warning of unsupported roof structures past the last installed roof bolts. In such case, the modules can be directly attached or hung from one or more of the last installed roof bolts to warn against entry into the unsupported areas. Once additional roof bolts have been installed, the old modules (with new batteries if appropriate) or new fully charged modules can be moved to the new last installed roof bolts to provide warning against entry into the new unsupported areas.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described a preferred embodiment of the invention.
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Brautigam Albert L.
Mayercheck William D.
Hofbass Jeffery
Klarquist & Sparkman, LLP
Nguyen Tai T.
The United States of America as represented by the Department of
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