None.
The present invention relates to a tamper-resistant shutter device incorporated into an outlet housing cover to prevent insertion of any object into an electrical outlet except a plug of matching configuration.
Electrical outlets including AFCI, GFCI, power strips, and extension cords are used to connect portable appliances and other electrical equipment. Most of the commonly available outlets are not protected from improper connections and entry of foreign metallic objects causing a major concern for the safety of users especially children or inexperienced individuals. To control said improper connections, a mechanism, device or assembly so configured to resist the entry of any object other than a plug that matches the configuration and geometry of the outlet could be incorporated into the outlet housing cover. In North America, outlets are configured according to their voltage and current ratings and referred to as the National Electrical Manufacturers Association configurations or commonly known as NEMA configurations. The most common household electrical outlet configurations are the NEMA 1-15R, 2-15R, 2-20R, 5-15R 50, 5-20R 51, 6-15R 52 and 6-20R 53, respectively for 125V/15A ungrounded, 250V/15A ungrounded, 250V/20A ungrounded, 125V/15A with ground, 125V/20A with ground, 250V/15A with ground and 250V/20A with ground. Electrical plugs NEMA 1-15P 43, 2-15P 44, 2-20P 45 may be used with outlets of the same configuration with or without ground. For purposes of this patent application, the term “ungrounded” refers to a plug or a receptacle outlet without ground connection, whereas the term “grounded” refers to a plug or receptacle outlet with ground connection.
There are electrical outlets provided with tamper-resistant shutters commercially available, however, most of them are limited to two configurations including the most common NEMA 1-15R and 5-15R 50. Most prior art designs do not provide total tampering protection for outlets with ground. The NEMA 1-15R is similar to the NEMA 5-15R 50 except that it has no ground connection.
With the limited protection and features offered by prior art designs, there is always a possibility to develop a better and more effective tamper-resistant shutter device for electrical outlets as with the present invention.
The present invention would apply to at least 7 different electrical outlet configurations including NEMA 1-15R, 2-15R, 2-20R, 5-15R 50, 5-20R 51, 6-15R 52 and 6-20R 53. For purposes of this patent application, specific NEMA outlet configurations are used, however, the same principles, methods and techniques may be used for other configurations including those used in other countries and standards.
The present invention affords protection for multiple outlet configurations and saves production costs and tooling. The present invention ensures an effective tamper-resistant protection by allowing only plugs of matching configuration to be used with the outlet, avoiding electrocution or other harmful incidents. For someone to use anything but the proper plug, it would require knowledge of the operating mechanisms of the present invention to articulate the geometry of a matching plug. The present invention employs multiple levels of protection through interlocked mechanisms so the device would only operate when both plug blades are inserted simultaneously. In case of a grounded plug, the present invention includes a ground pin lockout release mechanism 34 so the shutters to the electrical outlet only open when a matching plug configuration is used.
U.S. Pat. No. 7,452,221B1 (November/2008 Oddsen et al) disclosed a shutter device for a NEMA 5-15R electrical outlet different from the present invention which is designed to accommodate multiple configurations with and without ground. The Oddsen et al patent also refers to a shutter device relying on a sliding and pivotal movement of shutter members through a side frame to position the openings in the shutter plate with the outlet contacts. This is different from the present invention which uses wedge-driven positioning members to release locking mechanisms.
U.S. Pat. No. 7,312,394B1 (December/2007 Weeks et al) disclosed a shutter device for a limited configuration different from the present invention which accommodates multiple configurations, with and without ground. The Weeks et al patent also refers to a shutter device with a stationary positioning member and the other moving in the same plane but in opposite direction. This is different from the present invention which uses wedge-driven positioning members to release locking mechanisms for the plug to be used with the outlet. The ground pin release mechanism disclosed in the Weeks et al patent is offset from the center of the assembly due to space limitations, whereas the present invention employs a ground-pin lockout release mechanism directly at the centerline of the shutter frame. This is made possible by the space-saving configuration disclosed in the present invention.
U.S. Pat. No. 7,868,719B2 (January/2011 Bazayev et al) disclosed a shutter device for a limited outlet configuration different from the present invention which is designed to accommodate multiple configurations, with and without ground. The Bazayev et al patent also refers to a shutter device with two similar sliding plates moving in unison to align the plug blades with the receptacle outlet contact points which is different from the present invention which uses wedge-driven positioning members to release locking mechanisms to open access holes for the plug to be used with the outlet. The Bazayev et al patent also did not disclose any provision for ground-pin lockout release mechanism, which is provided with the present invention.
US2010/0041259 A1 (February/2010 Ni) disclosed a shutter device for NEMA 5-15R and 5-20R electrical outlets different from the present invention which is designed to accommodate multiple configurations, with and without ground. The Ni patent refers to a shutter device with independently movable spring-activated elements which differ from the present invention using wedge-driven positioning members to release locking mechanisms for the plug to be used with the outlet. The Ni patent did not disclose any provision for ground-pin lockout release mechanism, which is provided with the present invention.
US2009/0236115 A1 (September/2009 Li) disclosed a shutter device for a NEMA 5-15R electrical outlet different from the present invention which is designed to accommodate multiple configurations, with and without ground. The Li patent refers to a shutter device with two opposing spring-activated members overlaid against each other through their side openings to resist tampering. The present invention is framed and wedge-driven positioning members are used to release locking mechanisms to access the outlet. The Li patent did not disclose any provision for ground-pin lockout release mechanism which is provided with the present invention.
The present invention is focused on providing a safe, reliable and cost-effective means to avoid dangerous access to electrical outlets by children or inexperienced individuals. This is possible through the use of a tamper-resistant shutter device incorporated into an outlet housing cover. The mechanism may be used as accessory for outlet housing covers for AFCI, GFCI, power strips, extension cords and portable outlets. The present invention ensures that outlet contacts remain covered and only become accessible when a plug that matches the outlet configuration is used. To withstand reasonable usage and allow independent assembly, the shutter device is framed.
The present invention employs multiple interlocked wedge-driven positioning members to ensure a total tamper-resistant protection by allowing only plugs of matching configuration to be used with the electrical outlet. This poses a challenge for a child or any user to tamper with the device, avoiding electrocution or other harmful incidents. For someone to use anything but the proper plug, it would require knowledge of the operating mechanism of the present invention to articulate the geometry of the plug blades and ground pin. The wedge-driven positioning members ensure the shutters would only open when both blades of the plug are inserted simultaneously. The cover to the access holes on the frame only opens when the shutters are displaced a calculated distance to align with the outlet contact points. These wedge-driven positioning members are maintained in a default “closed position” by springs and stoppers when no plug is used with the outlet.
Certain standard NEMA outlet configurations are cited for reference in the present invention, however, adopting the same principles, methods or techniques for other configurations or styles used in other countries and standards will attain the same objective.
Not limiting the scope of the present invention, one skilled in the art may recognize the methods disclosed could apply to any other applications not mentioned herein with similar objectives.
References will now be made in detail to describe the exemplary embodiments of the present invention, which are illustrated in the accompanying drawings. Details disclosed herein are not to be interpreted as limiting, but rather as basis for the claims and teaching one skilled in the art how the present invention could be employed in any appropriately detailed system, structure or manner. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like components, or functions.
While the device is in a “shutter close”, or “default” position, or when no plug is inserted, the main shutter sub-assembly 100 and the ground pin lockout release mechanism 34 are in the following state:
When a plug such as NEMA 1-15P is used with the outlet with the ground pin lockout release mechanism 34 disabled, the following movements occur subsequently on the main shutter sub-assembly 100:
Pulling out a plug such as a NEMA 1-15P from the outlet with the ground pin lockout release mechanism 34 disabled, causes the main shutter sub-assembly 100 to return to its “default” or “shutter close” position by reversing the sequence outlined above.
While the tamper-resistant shutter device is in a “shutter close”, or “default” position, or when no plug is inserted, the main shutter sub-assembly 100, secondary shutter sub-assembly 200, and the ground pin lockout release mechanism 34 are in the following state:
When a plug is used on outlet configuration NEMA 2-15R, 2-20R, 5-15R 50, 5-20R 51, 6-15R 52, or 6-20R 53 with the ground pin lockout release mechanism 34 disabled, the following movements occur subsequently on the main shutter sub-assembly 100 and the secondary shutter sub-assembly 200:
Pulling out a plug such as NEMA 5-15P 46, 5-20P 47, 6-15R 48, or 6-20R 49 from the outlet in which the ground pin lockout release mechanism 34 is disabled, causes the main shutter sub-assembly 100 and the secondary shutter sub-assembly 200 to return to their default or “shutter close” positions by reversing the sequence outlined above.
When a plug is used on outlet configurations NEMA 5-15R 50, 5-20R 51, 6-15R 52 and 6-20R 53 with the ground pin lockout release mechanism 34 enabled, the following movements occur subsequently on the main shutter sub-assembly 100, secondary shutter sub-assembly 200, and the ground pin lockout release mechanism 34:
Pulling out a plug such as NEMA 5-15P 46, 5-20P 47, 6-15P 48, or 6-20R 49 from the outlet with the ground pin lockout release mechanism 34 enabled causes the main shutter sub-assembly 100, secondary shutter sub-assembly 200, and the ground pin lockout release mechanism 34 to return to their default or “shutter close” positions by reversing the sequence outlined above.
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Number | Date | Country | |
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20140065862 A1 | Mar 2014 | US |