MXPA97006686A - Wiring device with plate of fixing of set to tie - Google Patents

Abstract

The present invention relates to electrical wiring devices, such as female electrical plugs, switches and the like, and, more particularly, to wiring devices with a jaw for the ground connections of such devices. The present invention includes a pressure plate that engages the grounding plate of a female socket, the legs of a pressure plate being disposed within correspondingly shaped recesses next to the grounding plate of the socket, so that the pressure plate can not rotate substantially relative to the grounding plate so that a cable can be received between the ground plate and the pressure plate when the screw is removed a sufficient distance

Description

WIRING DEVICE WITH GROUNDING FIXING PLATE FIELD OF THE INVENTION This invention relates generally to electrical wiring devices, such as female electrical plugs, switches and the like, and, more particularly, to wiring devices with a jaw for the ground connections of such devices. BACKGROUND OF THE INVENTION Electrical wiring devices, such as sockets, switches, sockets and the like, are usually provided with screws with enlarged heads below which the bare end of an electric wire can be captured to form an electrical connection with the device. Wiring devices of this type to which this invention refers include at least three terminals: a charging terminal, a neutral terminal and a ground terminal. Connections must be made to all three terminals during normal use of the wiring device. Up to now, fixation plates for the load and neutral connections have sometimes been provided with the wiring device. However, special considerations associated with the connection made to the grounding terminal of the wiring device have excluded the use of jaws. When an electrical device is connected in series with other devices, it is desirable to maintain the continuity of grounding through the serial chain of devices, even if one of the devices is removed. If the wiring device's ground connections are made through two separate connections, continuity can not be maintained. It is desirable to remove the insulation from a contiguous length of grounding cable and make the connection to the wiring device without electrically separating the grounding wire in the device. To promote this type of connection, the electrical wiring devices are preferably provided with a single screw to make a ground connection to the device, and, in addition, they are not provided with a fixing plate, because the use of a metal plate Fixing on a grounding terminal will promote or at least facilitate the connection of two separate grounding wires to the grounding terminal, which could be separated when the wiring device is removed or replaced, thus producing a discontinuity in the ground connection in other wiring devices connected in series. When braided electrical cables are used to form connections with wiring devices, and in particular when a braided cable is used for the last electrical wiring devices of a chain of wiring devices in series, a screw, even a screw with a widened head , it is not entirely satisfactory to connect the braided cable to the wiring device. Although the strands of the cable are braided before the connection is made, the pressure between the screw head and the braided cable frequently causes the strands to dissociate from the remaining strand bundle, and thereby an unsatisfactory connection is made. An object of this invention is to provide a wiring device that overcomes the problems of prior art wiring devices, especially with respect to making ground connections with such devices. SUMMARY OF THE INVENTION Expressed succinctly, and according to a presently preferred embodiment of this invention, a wiring device includes a grounding plate with which a grounding connection is to be made; a threaded hole in the grounding plate; a screw engaged with the threaded hole and with a widened head; a pressure plate having a hole therethrough and engaging the screw between the screw head and the grounding plate of the wiring device; and cooperating means in the grounding plate and the pressure plate to substantially prevent rotation of the pressure plate with relation to the grounding plate when the screw is engaged with the pressure plate. According to another aspect of this invention, the pressure plate includes a rounded projection for guiding a cable attached to the wiring device to a fixed position with relation to the pressure plate. According to another aspect of this invention, the pressure plate includes a cutout region to substantially prevent two separate wires being simultaneously engaged by the pressure plate, one on each side of the screw.

The new aspects of the invention are set forth in detail in the appended claims. The invention itself, together with its other objects and advantages, can be more easily understood by reference to the following detailed description of one embodiment currently. preferred of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the electrical device according to the present invention. Figure 2 is a top view of the sheet metal pressure. Figure 3 is a side view of the pressure plate.

Figure 4 is a bottom view of the pressure plate. Figure 5 is a rear view of the electrical device. And Figure 6 is a perspective view of the earth plate with the pressure plate and a cable attached. DETAILED DESCRIPTION OF THE INVENTION A wiring device 10 of the type to which this invention relates is shown in Figure 1. The wiring device 10 has a device body 20 with a neutral terminal or terminals 13, a ground terminal 15 and a charging terminal or terminals 15 mounted to form electrical connections with the device. The grounding terminal includes an electrical conductive grounding plate 26, preferably a metal sheet which, more preferably still, forms the portion of the mechanical structure of the wiring device 10, and includes an internal portion, not shown, for make a connection with a female plug to receive a ground pin from an electric plug adapted to engage with the female plug. The electrically conductive metal sheet 26 is provided with a threaded through hole 38 extending through a generally rectangular folded tongue to receive a threaded screw 18 with a widened head 34 and preferably provided at its distal end with a interruption 30 in the thread to prevent the screw 18 from fully exiting the threaded through hole 38. The threaded through hole 38 of the tongue may be generally located in the center with respect to the tongue, or preferably biased toward an edge of the tongue. tongue, to reduce the possibility of connecting two separate wires to the tongue.

# A generally U-shaped pressure plate 12 has a generally flat base with a tapered concave rounded projection 22 formed on its edge to receive and guide an electrical connector under sheet 12, and legs first and second 14, 16 preferably arranged at an angle of approximately 90 ° with respect to the sheet 12 to engage cooperating holes or grooves 44 in the grounding plate 26 of the female electric plug next to the tab to prevent the sheet metal from Pressure 12 turn during use.

Preferably, the pressure plate 12 has a first relatively large uninterrupted portion 36 on one side of a central hole 24, which includes the rounded projection 22 for trapping the end of an electrical conductor between the pressure plate 12 and the plate of laying to ground 26 of the wiring device 10, thereby forming between them a connectable contact device. Preferably, the pressure plate 12 has a substantially reduced zone 32 between the opposite edge of the plate 12 and the central threaded hole 24 to reduce the The probability that a second separate electrical cable is connected to the earth plate 26 under the other side of the pressure plate 12. The electrical wiring device 10 with a pressure plate 12 according to this invention is easy to manufacture.

Preferably, as shown in FIG. 6, a grounding plate 26 is formed by appropriately stamping and bending a grounding strip in the configuration shown in FIG. 6 from a sheet of metallic material. A through hole 38 is formed in the tab of the portion of earth plate 26 of the strip, and is screwed to receive a screw 18 having a widened head 34.

• A pressure plate 12 having a generally U-shaped configuration with a generally flat base 40 and first and second legs 14, 16, is placed on the grounding plate 26 with the legs 14, 16 arranged 5 in recesses correspondingly 44, 46 in the grounding plate 26. Preferably, a screw 18 is screwed substantially completely into the central hole 24 of the pressure plate 12 and the hole 38 of the grounding plate 26, so that the threaded end of the screw 18 protrudes from the plate 26 on the side opposite the head. The threads on the end of the screw are then preferably interrupted and deformed to prevent the screw from completely coming out of the threaded hole. The pressure plate 12 engages the grounding plate 26 of the socket, with the legs 14, 16 of the pressure plate 12 arranged in recesses of corresponding shape next to the earth plate 26 of the socket, so that the pressure plate 12 can not rotates substantially relative to the grounding plate 26, when the screw 18 is sufficiently withdrawn so that a cable 42 can be received between the ground plate 26 and the pressure plate 12. (See Figure 6 ). Without the cooperating restricting action of legs 14, in the recesses 44, 46, the pressure plate 12 could easily rotate and misalign with the earth plate 26. The combination of the earth plate 26, the pressure plate 12 and the screw 18 can be then assemble in a complete female socket by adding their remaining elements, without danger that the pressure plate 12 is released from the grounding plate 26 or misplaced with respect to it.

Although the invention has been described in connection with its presently preferred embodiment, those skilled in the art will recognize that many modifications and changes can be made therein without departing from the true spirit and scope of the invention, which, therefore, is intended to be defined only by the appended claims.

Claims (14)

1. CLAIMS 1. A wiring device that includes: (a) a grounding plate with w a ground connection must be made; (b) a threaded hole in the grounding plate; (c) a screw engaged with the threaded hole and having a widened head; (d) a pressure plate having a hole therethrough and engaging the screw between the enlarged head and the grounding plate; and (e) a recess in one of the earth plate and the pressure plate and a corresponding leg in the other of the grounding plate and the pressure plate to substantially prevent rotation of the pressure plate with relation to the earth plate when the screw is engaged with the pressure plate. The wiring device defined in claim 1, wherein the pressure plate includes a rounded projection for guiding a cable attached to the wiring device to a fixed position relative to the pressure plate. The wiring device defined in claim 1, wherein the pressure plate includes a cutout region to substantially prevent two wires being simultaneously engaged by the pressure plate, one on each side of the screw. The wiring device defined in claim 1, wherein the screw includes a deformed end opposite the enlarged head to prevent the screw from coming out of the threaded hole, while allowing the screw to rotate. 5. The wiring device defined in claim 1, wherein the recess is in the grounding plate and the corresponding leg is in the pressure plate. 6. The wiring device defined in claim 1, wherein the grounding plate, the screw 5 and the pressure plate include a conductive material. The wiring device defined in claim 2, wherein the rounded projection is concave. 8. A wiring device that includes: (a) a grounding plate with w you can *;, 10 make ground connection; (b) a threaded hole in the grounding plate; (c) a screw engaged with the threaded hole and having a widened head; (d) a pressure plate having a hole therethrough and engaging the screw between the enlarged head and the grounding plate, and having a cutout region to substantially prevent two cables from being simultaneously engaged by the pressure plate , one on each side of the screw. 9. The wiring device defined in claim 8, wherein the pressure plate includes a rounded projection for guiding a cable attached to the wiring device to a fixed position relative to the pressure plate. 10. The wiring device defined in claim 8, wherein the screw includes a deformed end opposite the enlarged head to prevent the screw from exiting the threaded hole, while allowing the screw to rotate. 11. The wiring device defined in claim 8, wherein the grounding plate, the screw and the pressure plate include a conductive material. The wiring device defined in claim 9, wherein the rounded projection is concave. The wiring device of claim 8, including cooperating means in the grounding plate and the pressure plate to substantially prevent rotation of the pressure plate relative to the ground plate when the screw is engaged with the pressure plate. 14. The wiring device of claim 13, 10 wherein the cooperating means includes a recess in one of the grounding plate and the pressure plate, and a corresponding leg in the other of the grounding plate and the pressure plate to substantially prevent rotation of the plate. the pressure plate in relation to the sheet metal 15 earth, when the screw is engaged with the pressure plate.