Electricity: conductors and insulators – Boxes and housings – With electrical device
Reexamination Certificate
1999-08-06
2001-11-06
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
With electrical device
C174S051000, C174S053000
Reexamination Certificate
active
06313403
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to electrical wiring devices and more particularly to a wiring device having a one piece mounting strap and ground plate for reducing the number of parts needed to make the wiring device, and tracing the reliability and convenience thereof.
Electrical wiring devices of the type with which this invention is concerned include a ground plate, usually including a screw or other fastener for attaching a ground wire to the wiring device. Two types of ground plate are commonly used in known wiring devices. A first type of ground plate is integrally formed with a mounting strap portion of the wiring device, that is the plate or strap that is used to mount the device in an electrical junction box.
The mounting plate or strap is typically a stamped metal part, carrying the body of the wiring device in a center portion thereof and having axially extending mounting ears or plates through which mounting screws pass to attach the wiring device to a junction box. In accordance with one known technique for forming a grounding plate, a lateral plate is formed in the mounting plate when it is stamped out, and the plate is bent in a direction transverse to the long (axial) dimension of the mounting plate, and a mounting screw is fitted to the bent plate for attaching a ground lead. This technique is simple, inexpensive, and produces a good electrical connection because the ground plate is integrally formed with the mounting strap. However, this arrangement produces a ground screw that is oriented transversely to the axis of the wiring device, which is undesirable because it makes installation of the wiring device more difficult.
Another known wiring device arranges the ground plate so that the ground screw is oriented along the axis of the wiring device. This is preferred by installers, because installation is simplified, but heretofore all such arrangements have used a ground plate that is a physically separate element from the mounting strap, and which therefore must be physically and electrically attached to the mounting strap to form a low resistance connection that is also mechanically strong.
Providing a separate ground plate and attaching the ground plate to the mounting strap increases the cost of the wiring device, and can decrease the reliability thereof because of the need for making a mechanical and electrical attachment between the ground plate and the strap.
It is an object of this invention to overcome the disadvantages of both known constructions by providing a wiring device having a grounding plate that is integrally formed with the mounting strap and which includes a screw that is oriented along the axis of the wiring device.
It is another object of this invention to reduce the number of parts needed to form a wiring device having a grounding plate and screw oriented as described.
SUMMARY OF THE INVENTION
According to one aspect of this invention, an electrical wiring device comprises a body; a mounting strap attached to the body and having a longitudinal axis, a grounding plate attached to the body and extending at right angles thereto, and an opening for receiving a grounding screw having an axis aligned with the longitudinal axis.
According to another aspect of this invention, a mounting strap for a wiring device having a longitudinal axis comprises a grounding plate at least a portion of which extends perpendicular to the longitudinal axis, and an opening in the grounding plate for receiving a fastener, the opening having an axis oriented parallel to the longitudinal axis, so that the fastener is oriented parallel to the longitudinal axis.
In accordance with a presently preferred aspect of the invention, a wiring device includes a one piece metal strap having end portions adapted to be attached to a junction box, a central opening, and a ground plate integral with the mounting strap having a first portion extending parallel to and adjacent the mounting strap, and a second portion substantially at right angles to the mounting strap.
REFERENCES:
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Livingston Thomas
Myers John F.
Estrada Angel R.
Pass & Seymour, Inc.
Reichard Dean A.
Wall Marjama & Bilinski
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