Electricity: electrical systems and devices – Safety and protection of systems and devices – Ground fault protection
Reexamination Certificate
2002-06-26
2003-09-16
Jackson, Stephen W (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
Ground fault protection
Reexamination Certificate
active
06621671
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to electrical hazard prevention, and more specifically to a shock hazard prevention system for disconnecting an electrical load from an electrical source when a shock hazard condition exists within the load.
2. Description of the Related Art
Devices for protecting human life and property against electrical shock and damage resulting from a shock hazard condition within an electrical load are known. For example, the model No. 6199 ground fault circuit interrupter (GFCI) marketed by the assignee of the present invention is capable of sensing and responding to the inadvertent grounding of the neutral conductor of an A-C electrical distribution system. It is noted, however, that in certain applications the utilization of such a GFCI is not practical.
In particular, the GFCI is a relatively expensive and complex device which requires the utilization of several transformers. In addition, the GFCI is often hardwired in a wall outlet or receptacle and is neither portable nor readily disconnected. Thus, unless each outlet in which an electrical device such as, for example, an appliance is to be utilized is protected by a GFCI, the user of the appliance is subject to possible injury if a shock hazard condition should exist in conjunction with a non-protected outlet.
In addition, in certain environments the utilization of a conventional GFCI would not afford any shock hazard protection to the user of an appliance. More specifically, a conventional GFCI device of the type known to applicants will not be effective or work if the user of an electrical appliance drops the appliance in a plastic insulated bathtub.
Another potential drawback, exists regarding the use of a GFCI for certain types of portable electrical appliances such as, for example, a hair dryer. Although the owner of a hair dryer may have his or her residence outlets adequately protected by GFCI devices, it is possible that other places, such as hotels, the residence of relatives, friends, etc., where it is desired to use the hair dryer may not be protected by such devices.
Accordingly, it is clear that what is needed is a shock hazard protector which is associated with the appliance to be protected itself rather than with the electrical outlet in which the appliance is plugged and energized. It is believed that prior to the present invention, this need has gone unfulfilled.
A need exists for a shock hazard protector which possesses attributes including having a minimum number of components, reliability, cost and portability.
BRIEF SUMMARY OF THE INVENTION
It is accordingly a general object of this invention to overcome the aforementioned limitations and drawbacks associated with the known devices and to fulfill the needs mentioned by providing a hazard protection system having all of the desirable attributes noted above.
It is a particular object of the present invention to provide a shock hazard protector capable of disconnecting an electrical source from an electrical load in response to the detection of a shock hazard condition within the electrical load.
Another object of the present invention is to provide a shock hazard protector capable of detecting and responding to a water-related shock hazard condition within an electrical appliance.
A further object of the present invention is to provide a shock hazard protection system, as above, incorporating immersion detection circuitry.
A still further object of this invention is to provide a shock hazard protection system, as above, wherein a feature is provided for detecting a possible break or discontinuity in a sensing or guard wire.
Yet another object of this invention is to provide a system, as above, wherein a solenoid-type electromechanical mechanism acts as a circuit breaking or interrupting means.
A further object is to provide such a system wherein a relay and associated circuitry and mechanical means enable the desired result.
Yet a further object of this invention is to provide a detection system which detects or senses the presence of a conductive medium, and which causes an event in response thereto.
Another object of this invention is to provide a detection system which detects or senses the absence of the presence of a conductive medium, and which causes an event in response thereto.
Other objects will be apparent from the following detailed description and practice of the invention.
The foregoing and other objects and advantages which will be apparent in the following detailed description of the preferred embodiment, or in the practice of the invention, are achieved by the invention disclosed herein, which generally may be characterized as a hazard protector. The hazard protector includes detecting means associated with a load for detecting a hazard condition within the load, an interrupting means associated with a source to which the load is operatively connected, and conducting means connected between the detecting means and the interrupting means. In response to the detection of a hazard condition within the load by the detecting means, the interrupting means operatively disconnects the source from the load.
REFERENCES:
patent: 4270158 (1981-05-01), Gilardoni et al.
patent: 4464582 (1984-08-01), Aragaki et al.
patent: 4589047 (1986-05-01), Gaus et al.
Gershen Bernard
Pearse James N.
Rosenbaum Saul
Jackson Stephen W
Leviton Manufacturing Co. Inc.
Sutton Paul J.
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