US3064224A

US3064224A - Wiring device with grounding means

Info

Publication number: US3064224A
Application number: US826173A
Authority: US
Inventors: Roy O Wiley
Original assignee: Bryant Electric Co
Current assignee: Bryant Electric Co
Priority date: 1959-07-10
Filing date: 1959-07-10
Publication date: 1962-11-13
Anticipated expiration: 1979-11-13

Description

Nov. 13, 1962 R. o. WILEY WIRING DEVICE WITH GROUNDING MEANS Filed July 10, 1959 INVENTOR Roy 0. WIIey W ATT' NEY WITNESSES dfiiidizd Patented Nov. 13, 1962 WERZING DEVEQE WITH GRQUNDING MEANS Roy 0. Wiley, Bridgeport, Conn, assignor to The Bryant Electric Company, Bridgeport, Conn, a corporation of Connecticut Filed July It), 1959, Ser. No. 826,173 4 Claims. (ill. 339-14) 'Ihe present invention relates to electrical wiring devices, and more particularly to receptacles in which a grounding connection is provided.

In applications where electrical potentials of a value substantially above ground potential are found to exist, it is often desirable in the interest of safety to provide an electrical connection to ground from any normally neutral structures which are likely to be contacted by operating personnel. Such a connection, then, ensures that the mentioned structures will continuously exist at ground potential and therefore cannot exist at any higher electri- 1 cal potential as a result of any coupling with any other environmental structure having such a higher potential.

I If, for example, a metallic casing or housing or other structural member for an electrical device is to be grounded, it is desirable that such a grounding connection be made with the same motions that are made for establishing other electrical connections for the electrical device. In such a case, it is common to make use of a grounding prong which is projected, along with other or energizing prongs, from a terminal plug of the device and which is connected to the housing of the device. When the plug is inserted in a receptacle for connection to an electric energy source, the grounding prong is then engaged by a contact which is provided in the receptacle and which is permanently connected to ground.

'Ihus, each'time the electrical device is connected to the receptacle, a ground connection for the housing of the device is assured provided the grounding prong and the grounding contact of the receptacle make a reliable contact and provided the grounding contact of the receptacle is reliably and permanently connected to ground. The present invention is directed toward these last-mentioned provisions.

It is therefore, an object of the invention to provide a novel wiring device in which a reliable ground connection is provided.

It is another object of the invention to provide a novel wiring device for which a grounding connection is provided integrally on a conductive support member for the wiring device.

It is a further object of the invention to provide an electrical receptacle in which grounding means are reliably yet economically included with the further advantage of being readily accessible for establishing a permanent grounding connection thereto.

These and other objects of the invention will become more apparent upon consideration of the following detailed description of an illustrative embodiment of the invention in relation to the accompanying drawings, in which: 7

FIGURE 1 is a top plan view of an assembled electrical receptacle constructed in accordance with the principles of the invention;

FIG. 2 is a bottom plan view of the receptacle shown in FIG. 1 with only one terminal inserted therein;

FIG. 3 is an exploded isometric view of a mounting member for the receptacle in FIG. 1 and for which grounding means are shown in a preassembled position.

In accordance with the broad principles of the invention, a wiring device comprises an integral housing that receives and readily engages terminal members and a mounting means on which prong engaging contacts and a permanent ground connecting member are provided for reliable and durable operation. Although the illustrated electrical receptacle will be described to point out the invention, other wiring devices having modified structures will obviously appear to those who are skilled in the art to which the invention belongs without departing from the principles of the invention. Accordingly, in view of this consideration, the detailed description of the illustrative embodiment of the invention will now follow.

With reference to FIGS. 1, 2 and 3, an electrical receptacle 8 comprises an elongated housing member 1%, amounting member or yoke 12, and terminal members 14. The housing 10 is integrally molded from a material having insulative and mechanical properties suitable for the intended application of the receptacle 8. The structure of the housing It} is such that it can support and insulate the terminals 14 and, additionally, can support the mounting member 12 whereby the cooperative assemblage forms the receptacle 8 which then functions in a fashion to be explained more fully hereinafter.

The housing it) includes two elongated terminal receiving piers 16 having a channel 13 (FIG. 2) therebetween. The piers 16 are spanned by facedportions 2i) that can support electrical plugs (not shown) having prongs for insertion into the receptacle it. The mentioned channel 18 serves to receive the mounting member 12 in a manner which will become more apparent later in the description.

Structural walls

22, 26, 28 and 3d are formed to present substantially a rectangular parallelepiped geometry for each of the piers 16. Within the

walls

22, 26, 2S and 3% is a chamber 24 for the reception of the terminal 14. A particular description of the principles which govern the engagement of the terminal 14 by the pier l6 and the functional cooperation between these members is fully set forth in a copending application of S. A. Mason, entitled Wiring Device, filed July 10, 1959, Serial No. 826,266, and assigned to the present assignee. It will sufiice to note here that, after engagement of the terminal 14 by the pier 16, an electrical contact or blade 32 on each end of the terminal 14 is positioned within the pier 16 in a manner permitting engagement with a prong of an inserted plug, reference to which has already been made.

The end wall 26 is provided with a projecting ridge 34ialong its inward lateral edge for engagement with the mounting member 12 during assembly of the receptacle 8. The other end wall 23 of each of the piers 16 is similarly provided with a projecting ridge 36 for engagement of the mounting member 12. Additionally, a transversely extending groove 38 is provided in each wall 23 for guidance and retainment of a portion of the mounting member 12. This latter relation will be more fully understood upon detailed consideration of the mounting member 12.

The Wall 30 on the inner side of each of the piers i6 is provided with transversely extending ridges 46 to serve as fulcrum points for grounding contacts, to be described hereinafter, on the mounting member 12. Additionally, a longitudinal midsection 42 of each side wall 30 is generally recessed from the plane of the side wall 3t} in order to provide for reception of a corresponding midsection 43 of the mounting member 12. Themidsection 42 also provides for stable engagement of the mounting member 12 by means of transversely extending ridges 44.

The mounting member 12 is most advantageously viewed in FIG. 3. It is an elongated member constructed from a conductive but resilient material, such as sheet steel, and adapted to be supported, as previously indicated, by the housing 10. An elongated strip 46, with the broadened midsection 48, to which reference has previously been made, constitutes a substantial part of the length of the mounting member 12. Adjacent each end of the mounting member 12, a riser 56 extends upwardly to a longitudinally projecting car 52. There is an'aperture 54 for passage of a mounting screw (not-shown) in eachof the projecting cars 52. What is generally denoted as an end section 56 or 53 extends from the strip 46 to a lower portion of the riser 59 adjacent each end of the mounting member 12. Apertures 69 for passage of a grounding prong, referred to hereinbefore, are provided in the end section 56 and, additionally, in the midsection 48 of the strip 46. The midsection 48 also includes an opening 62 through which a suitable fastener may be passed for securing a faceplate (not shown) over the receptacle 8 when it is mounted.

Each of the

end sections

56 or 58 additionally has inwardly projecting cantilever tabs 64 for engagement with the. housing 1%. The endsection 58 .has transversely extending arms66 of which the ends are interconnected by acrossplate 68.. The crossplate 68 can beattached to the ends of the arms 66 by any convenient means, as by welding portions 67 of the crossplate 68 to sides 69 of the arms 66 or, in certain instances, can even be integrally formed therewith. When the crossplate 68 is attached to the arms 66, an end portion or extension 70 of the crossplate 68 projects beyond the lateral limit of each arm 66. Each of the crossplate end extensions '70 then accede to the character ofv a railing which is to be guided into the previously-mentioned pier grooves 38' during assembly of the wire device.

A grounding contact 72 is formed from resilient wire into a shape substantially as shown in FIG. 3 and is attached to the mounting member 12 adjacent each of the grounding prong apertures 69 so that the generally U-shaped configurations of the aperture 60 and of the grounding contact 72 are in alignment. This attachment can be accomplished in any of a number of ways, but, in the embodiment shown, it is preferably made by welding.

Prior to any assembly of the receptacle'8 the grounding contacts 72 and the'crossplate 68 can be united with the bodyof the mounting member 12 as indicated above. An assembly of the receptacle 8 can then be accomplished by first inserting a terminal 14 in each of the piers 16 of the housing in a manner fully described in the previously mentioned copending application. The mounting member 12 can then be assembled with the housing 10 in a manner such that the mounting member strip 46 passes into the channel 18 betwen the piers 16 of the housing 10. When the mounting member 12 is inserted to a position against under surfaces 74 of the faced portions 20, engagement of the mounting member 12 with the housing 1% can then be made, desirably by applying an impulsive force to the cantilever tabs 64 and thereby inbedding the tabs 64 in the projecting

ridges

34 and 36 of the

pier end walls

26 and 28. However, in certain cases such as those instances pointed out in the mentioned copending application, the mounting member 12 can be engaged with the housing 10 through frictionalcooperation without the application of an impulsive force. Additional stability, contributing to engagement between the mounting member 12 andthe housing 10; exists between the mounting member strip -46 and the

side wall ridges

40 and 44. Furthermore, the end extensions or railings 70 of the crossplate 68 will have been guided into a position within the grooves 38 of the end walls 28. This latter relationship provides, among other things, lateral stability for the crossplate 68 and the arms 66. It is to be noted, however, that the crossplate 68 can be attached to the mounting member 12'after' the mounting member 12 is assembled with the housing 10.

With the mounting member 12 fully inserted, the

' grounding prong apertures 60 of the mounting member 12 are in alignment with grounding prong openings 76 provided in the faced portions 20. A terminal screw 77 can be passed into an opening 78 of the crossplate 68 as means for engaging a wire or other conductor maintained at 2. ground potential. It will,...accordingly, be realized that when a grounding prong makes electrical contact with the mounting member grounding contact 72 an electrical connection will exist between the prong and ground.

When the receptacle 8 'is-placed in use, the aforementioned plug with a groundingprong can be inserted into the receptacle 8 so that" the grounding prong passes through the opening 76 of one of the faced portions 26.

There are ordinarily two-remaining plug prongs which then pass through faced portion slots 80 into engagement with the terminal blades 32'located within the housing '26. Upon passage of the grounding prong through the faced portion opening 76 and consequently through and beyond the mounting member aperture 69 in alignment therewith, a reliable electricalconnection is made between the prong and the mounting member grounding contact 72. This connection is occasioned by legs82 of the :contact 72 which are sufficiently resilient to exert a clamping force upon the grounding prong. ,A full description of the relationships which operate to provide this connection appears in a copending application of C. Smith,-en- Y titled Wiring Device, filed November 29, 1957, Serial No.

699,765, was assigned to the present assignee; It will be noticed, however, that the present construction-of the grounding contact 72 is such that a point of stress concentration exists at each portion 84 0f the-contact 72 which is adjacent the fulcrum ridges -46 of the housing 10.

With the concentration of any existing stress at these points of the grounding contact, little or no stress is transmitted to bight 86 where the grounding contact 72, in this example, is welded to the mounting member 12.

Although the receptacle, described herein is not shown to have an insulative cover for the underside of the piers 16, such a cover can be provided in accordance with the principles of an invention described in another copending application of S. A. Mason, entitled Wiring Device, filed July 10, 1959, Serial No. 826,218, and assigned to the present assignee. It remains to be noted that the construction of the receptacle is certainly economical for the component parts of the receptacle are minimized in number and are simplified in structure. This economy of con-- struction, however, does not impair the reliability of any operation of the receptacle. It is particularly noteworthy that a reliable grounding connection is" always available for the receptacle. V

In the fo'regoingdescription, an embodiment of the invention, as already indicated, has been described for illustrative purposes only. Accordingly, it is desired that the invention be not interpreted'as being limited to the described embodiment, rather it is desired that it be accorded an interpretation consistent with the scope and- V spirit of its broad principles.

. said prong is inserted therebetween, said mounting mem- V What is claimed is: 7 r 1. An electrical wiring device adapted for reception of a plug having a grounding prong, said device comprising 7 an elongated housing having spaced projecting portions extending transversely of said housing, a terminal mounted within each of said portions, a -conductive, elongated mounting member, and resilient, conductive arms being arms for concentrating at the intermediatearm portions.

forces originating in the spaced ends of said arms when her additionally having a substantially transverse portion engaging said housing portions, and said transverse por-' tion having means for engaging a grounding conductor,

whereby said prong can be connected to said mounting member arms for a grounding connection with'said conductor.

2. An electrical wiring device adapted for reception of a plug having a grounding prong, said device comprising an elongated housing having spaced projecting portions extending transversely of said housing, a terminal mounted within each of said portions, a conductive, elongated mounting member, and resilient arms being positioned longitudinally of said mounting member, said arms being spaced adjacent one end thereof and aligned with the insertional path of said prong and being in proximity to one another adjacent their opposite ends, means for joining said arms at their proximate portions to said mounting member, means on said housing portions positioned against an intermediate portion of each of said arms for concentrating at those portions forces originating in the spaced ends of said arms when said prong is inserted therebetween.

3. An electrical wiring device adapted for reception of a plug having a grounding prong, said device comprising an elongated unitary insulative housing having spaced elongated portions and having an elongated channel extending in length between said spaced housing portions from one end thereof to the other end thereof and extending in depth from a rear side thereof to an inner surface of a front housing Wall, an elongated grounding mounting member having an elongated portion located in said channel adjacent said inner wall surface and having respective mounting ears extending longitudinally outward of the ends of said housing, means for supporting said mounting member relative to said housing, a pair of arms spaced laterally of said mounting member and extending substantially perpendicularly rearwardly from said mounting member adjacent one end of said channel, an elongated crossplate bridging said arms laterally of said mounting member and being secured to said arms, the opposite end portions of said crossplate extending beyound the laterally outer arm sides, respectively, said crossplate end portions matingly supported in respective guide groves opposingly located in said spaced housing portions and extending from said rear housing side substantially perpendicularly toward said front housing wall, and means for engaging a wire with said crossplate.

4. An electrical wiring device adapted for reception of a plug having a grounding prong, said device comprising an elongated unitary insulative housing having spaced elongated portions and having an elongated channel extending in length between said spaced housing portions from one end thereof to the other end thereof and extending in depth from a rear side thereof to an inner surface of a front housing wall, an elongated grounding mounting member having an elongated portion located in said channel adjacent said inner wall surface and having respective mounting ears extending longitudinally outward of the ends of said housing, means for supporting said mounting member relative to said housing, at least one arm extending substantially perpendicularly rearwardly from said mounting member adjacent one end of said channel, an elongated crossplate extending across said arm laterally of said mounting member and being secured to said arm, the opposite end portions of said crossplate extending beyond the laterally outer sides of said arm, respectively, said crossplate end portions matingly supported in respective guide grooves opposingly located in said spaced housing portions and extending from said rear housing side substantially perpendicularly toward said front housing wall, and means for engaging a Wire with said crossplate.

References (Iited in the file of this patent UNITED STATES PATENTS 1,648,797 Cohen et al Nov. 8, 1927 1,915,070 Muldoon June 20, 1933 1,927,245 Russell Sept. 19, 1933 2,519,121 Del Camp Aug 15, 1950 2,686,297 Hutt Aug. 10, 1954 2,890,265 Smith June 9, 1959 2,974,301 Slater Mar. 7, 1961