US3001168A - Wiring device - Google Patents

Description

Sept. 19, 1961 c.-M. SMITH 3,001,168

WIRING DEVICE Filed OGt. 2l. 195'? 2 Sheets-Sheet 1 27 Y @jr ll Sept. 19, 1961 c. M. SMITH 3,001,168

WIRING DEVICE Filed oct. 21. 195? 2 Sheets-Sheet 2 6l Fi g. 9.

WITNESSESt |NVENTOR @MMSI G- Clarence M. Smh

ATTORNEY atei 3,0@Ll63 Patented Sept. 19, 1961 Conn., assigner to The Bridgeport, Conn., a corpo- This invention relates generally to electric wiring de'- vices, and more particularly to wall outlets for use with plug connectors to connect various fixtures to a house circuit.

yln the past unitary contact and terminal members have been provided for electric wiring devices wherein the terminal portion thereof is of the screwless terminal type and the contact portion is adapted to receive the prongs of a male electrical plug. A problem has been encountered for unitary terminal and contact structures of this type particularly where the terminal portion is provided with a pair of spaced wire grips which are formed by slotting the terminal portion longitudinally and where female contacts are located to extend laterally from opposite ends of the wire grips. In these constructions the female contact comprises a pair of spaced portions ex* tending laterally from each end of the wire grips. T he aforementioned problem arises when a lead wire is inserted into the slot to enga-ge the wire grips or when a male prong engages the female contact. The insertion rof the lead wire causes the grips to move upwardly in the direction of insertion of the lead wire and outwardly toward its side edges. The stresses formed in the member by the aforementioned motion of the wire grip is transmitted to the female contact portions and causes them to spread further apart, whereby the contact pressure exerted on the male prongs is decreased, and an undesirable and ineflicient connection between the wiring device and the male plug is created. Similarly, the engagement of the female contact with a male prong causes the female contact portions to be spread apart, which motion is transmitted to the wire grips to weaken the connection between the wire grips and a lead wire. The prior art `structures have attempted -to reduce this adverse effect by making slight enlargements of the slot adjacent the ends of the wire grips, but the resulting structure has not been successful.

The present invention is specifically directed toward the elimination of the aforesaid problem by providing means on the unitary structure for localizing stresses built up in the wire gripping portions and the prong engaging portions thereof. A unitary female contact is substituted for the pair of spaced portions provided in the prior art. The unitary female contact is preferably U-shaped and has one of its side edges connected to the end of the unitary structure through a rigid transition member. Thus, a male prong is engaged by the spaced arms of the U-shaped female contact and any stresses built up in the arms are absorbed in movement of the arms relative to each other and in the rigid supporting structure of the female contact. Located between the wire grips and the rigid support structure are sections greatly reduced in area so that upon stressing of the wire grip by a lead wire, the stresses built up are absorbed by the reduced area sections and are not transmitted to the female contacts.

An object of the invention is to provide an improved electric outlet of simplified construction.

Another object of this invention is to provide an electrical device to which a wire may be easily and quickly attached.

Another object of this invention is to provide an improved unitary connector structure for a wire device having spaced wire gripping and contact engaging portions and formed so that stresses built up in one of these portions is not transmitted to the other.

Still another object of this invention is to provide an improved connector structure for a wire device having means for limiting the movement of wire gripping means formed thereon which move in response to the insertion of a lead wire.

Another object of this invention is to provide an irnproved connector structure for wiring devices in which the wires are connected to the wiring device and locked in place with good electrical connections by inserting the stripped end of the wire through an opening in the housing of the device.

The invention both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed de scription of several embodiments thereof, when read in conjunction with the accompanying drawings.

In said drawings:

FIGURE l is a front elevation of a receptacle embodying the principles of the invention;

FIG. 2 is a front elevational view of the receptacle shown in IFIG. l with cover removed;

FIG. 3 is a plan view of one of the connecting strips with the integral contacts;

FIG. 4 is a side elevational View of strip shown in FIG. 3;

FIG. 5 is a sectional view taken on line V-V of FIG. l and looking in the direction of the arrows;

FIG. 6 is a rear elevational view of the receptacle shown in FIG. l showing the wire receiving hol-es and release openings through which a tool is inserted to release the Wires;

FIG. 7 is a sectional view taken on line Vil-VII of FIG. 6 and looking in the direction of the arrows;

FIG. 8 is a perspective view showing a side wiring device for use with a modified conducting strip similar to that shown in FIGS. 3 and 4; and

FIG. 9 is a transverse sectional view of the device shown in FIG. 8 assembled in a receptacle.

Referring to the drawings, the receptacle comprises an upper housing 11 and a lower housing V13, both of molded insulating material, a pair of elongated electrical contact members or terminals 15 and a yoke 17 for mounting the receptacle in a suitable outlet box. Referring to FIGS. l, 5 and 7, the upper housing portion 11 is an irregularly formed member having irregularly formed, downwardly extending, laterally spaced side portions 19 and a pair of longitudinally spaced faces 21 substantially oval in shape and having spaced slots 23 therein for receiving the prongs of a male plug.

The lower housing 13 comprises a substantially rectangular base having upwardly extending side walls 25 and end walls 27. The lower edges of the side walls 19 of the upper housing 11 are adapted to engage the side walls 25 of the base when the receptacle is assembled. The two parts of the housing are secured together by means of screws 29 (-FIG. 6) which pass upwardly through the bottom portion or base 13, through openings (not shown) in the yoke 17 and are threaded into openings in the upper portion 11 of the housing. A centra-l opening 31 (FIG. l) in the upper portion 11 of the housing and a threaded opening in the yoke 17 `are provided for the purpose of attaching a ush cover plate to the receptacle.

The base 13 is longitudinally divided into two symmetrical spaces or compartments 33 by a pair of central longitudinally spaced ribs 35. Each of the compartments are provided with surfaces and projections for receiving and retaining a conductive connecting or contact member yas shown in FIGS. 3, 4 and 8. Each side wall 25 of the base 13 is provided with longitudinally spaced ribs or projections 37 for locating the contact members 15 the conducting lengthwise in the base. Extending transversely across the bottom portion of the base adjacent the ribs 37 are ribs 39 upon which the contact portions of the connecting member l5 rest when placed in position. The upper housing ll (FIGS. 5 and 7) is provided with downwardly extending projections 41 spaced on opposite sides of the transverse center base of the receptacle with a transverse space 43 therebetween. A spacer 45 disposed transversely of the base inthe space 43 has downwardly extending prongs 47 (FIGS. 7 and 9) for engaging the edges of the termina-ls or connecting members l5 to hold them in place. As seen in FIGS. 2 and 9, the ends of the spacer 45 engage in vertical slots 49 in the side walls 25 of the base. As seen in FIGS. 7 and 9, the spacer 45 is held in place by the upper housing member ll `and by the yoke I7 when the receptacle is assembled.

When the connecting or contact members l5 (FiG. 2) are assembled in the base 13, they `are accurately located and held in position by the ribs 37, 139 and 35, by the side walls 25 of the base i3, the spacer 45 and by the upper housing member 1l without being positively attached to the housing. FIGS. 3 and 4 illustrate a contact member 15a which is generally the same as the contact member 15 shown in FIGS. 2, 5 and 8 with the exception that the contact blades at the ends thereof extend transversely of themain body of the contact member whereas the contact blades of the members 15 (FIG. 8) extend longitudinally of the contact member. By assembling the contact members 15 (FIG. 2) in the base 13 male plugs havingtheir prongs spaced laterally may be inserted through the housing slots 23 (FIG. l). If the contact members 15a (FIGS. 3 and 4) are assembled in theV receptacle, male plugs having their prongs spaced edgewiise may be inserted in the slots 23.

Referring to FIGS. 2 and 8, the terminal members l5 are formed from a flat strip of resilient conductive material, such as brass or copper, by any suitable mechanical process, such as stamping. When so formed, each elongated contact member 15 hasan upwardly extending portion 5l at each end thereof from which spaced contact l lades 53 extend longitudinally outward and are disposed beneath the housing slots 23 to be engaged by the prongs of an inserted connector plug. Openings 57 are formed in `the main body of the contact member l5 adjacent to but spaced from the upaturned portions 51 and a slot 59 extends between the openings 57 along the longitudinal center line of the contact member 15 to form wire gripping or spring locking tongues 6l. The spring locking tongues 61 `are formed upwardly at opposing angles (FIG 7) and in their assembled positions rest on inclined surfaces 63 on the base 13; Recesses 65 are formed in the outer edges of the gripping or locking portions 6i to per- -rnit twisting at these points and thus prevent torsion stresses from being transferred to the base 51 of the female contact blades 53.v

In order to connect `a lead wire or a conductor to the Contact members l5, it is necessary merely to insert the stripped end of a wire into an opening 67 in the lower housing i3 (FIGS. 5, 6 land 7). When thus inserted, the end 69 of the wire engages between the gripping edges of the gripping or locking portions 6l and separates them to be held firmly in the slot 59 and to make a good electrical connectionV with the contact member l5. Obviously, any y'attempt to withdraw such an inserted wire results in the gripping edges of the locking portions 6l more firmly engaging the wire.

When -a plug is inserted into the contact blades 53 in a twisted or slanted manner, the blades 53 can respond to the twisting or distorting effect by deiecting about portions indicated by the reference character 71 (FGS. 2 and S) or by twisting about the narrowportions adjacent the openings 57 without disturbing the spring locking tongues 6l yand thus maintain good gripping tension Ilon the lockingV tongues-6l.y By the same token, the locking portions-61,1,when deflected `,by lan inserted wire by a twist- 4 ing action localized at recesses 65, do not alfect the blades 53.

As previously stated, the contact member `15a shown in FIGS. 3 and 4, except for the arrangement of the female contacts 53a at the ends thereof, is the same as the contact i5. The contact` blades 53a are supported on base portions 51a `and extend transversely of the longitudinal.

center line of the termina-l 15e instead of longitudinally thereof as in FIGS. 2 and 8.

FIGS. 8 and 9 illustrate an adapter as well as a modified base i3d whereby a receptacle provided with the contact mem-bers l5 is connected for side wiring. Terminal piates 73 provided with connecting screws 75 are disposed one against each of the opposite sides of the base 13a. Formed integral with the terminal plate 73 and at right angles thereto is a conductive strap '77 which extends through the base 13a and which has an upwardly turned portion at the inner end thereof which is inserted between the spring locking tongues 61 0f the terminal 15 as shown in FIGS. 8 and 9. The openings in the base 13a through which the straps 77 extend are slightly wider than the straps 77 and a piece of insulating material 81 is suitably provided on the base 13a to minimize exposure of the straps 77. n

As shown in FIGS. 5, 6 and 7, access openings 83 are provided in the bottom of the base 13 through which a tool, such as a screw device, can be inserted between the spring locking tongues 61 and, by a slight twist, force the tongues 6l apart to release the Wire 49.

The invention provides a pair of easily formed terminals which may be inserted into and properly located within the receptacle without the use of tools and which is held in position without being positively fastened to the receptacle housing. When assembled in the receptacle the terminal is readily connected to an electrical conductor by merely inserting the conductor through a suitable opening in the bottom of the receptacle and forcing the bared end thereof between the spring locking tongues so that it is gripped by the tongues. It will be further noted that the spring locking tongues are free of any distortion or twisting of the female contacts upon the improperinsertion of the prongs of a male plug, and the contacts are unaffected by deection of the wire locking tongues.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is-to be understood that various changes and modifications in the structural details thereof may be made without departing from the spirit of the invention.

l claim as my invention:

l. A wiring device comprising a hollow casing of insulating material7 an elongated terminal member disposed in fixed relationship within said casing, a pair of spring locking tongues formed longitudinally on said terminal member and spaced apart to engage iirmly a conductor inserted therebetween, a terminal plate having a wire engaging portion positioned outside said casing and having another portion extending Ythrough a passage in said casing, said other terminal portion having its inner end rmly engaged by said locking tongues on said terminal member, and means for precluding detlecting forces on said tongues from elfecting the remainder of said terminal.

2. A wiring device comprising a hollow casing of insulating material, an elongated terminal member disposed in fixed relationship within said casing, a pair of spring locking tongues formed longitudinally on said terminal member and spaced apart to engage firmly a conductor inserted therebetween, a pair of contact blades formed on each end of said terminal member, a terminal plate having one portion positioned outside said casing and having another portion extending into said casing, said other plate portion having its inner end rmly engaged by said locking tongmes on said terminal member.

3. A wiring device comprising a hollowV casing of insulating material, an elongated terminal member disposed in fixed relationship within said casing, a pair of spring locking tongues formed longitudinally on said terminal member and spaced apart to engage rmly conductor inserted therebetween, a pair of contact blades yformed on each end of said terminal member, portions on said terminal member located between said contact blades and said spring locking tongues being reduced in cross-sectional area to prevent stresses on said contact blades from being transmitted to said spring locking tongues by enabling said blades and said tongues to be deliected about said portions, respectively, a terminal plate having one portion positioned outside said casing and having another portion extending into said casing, said other plate portion having its inner end firmly engaged by said locking tongues on said terminal member.

4. A wiring device comprising a hollow casing of insulating material, an elongated terminal member disposed in iixed relationship within said casing, a pair of spring locking tongues formed longitudinally on said terminal member and spaced apart to engage firmly a conductor` inserted therebetween, a terminal plate having at least a portion thereof exposed to the exterior of said casing and having another portion firmly engaged by said locking tongues on said terminal member.

5. A wiring device comprising an elongated casing of insulating material, an elongated `generally rectangular and resilient terminal being supported within said casing, a face side of said terminal extending longitudinally adjacent a back side of said casing, said terminal including a pair of conductor engaging tongues extending in the longitudinal direction and having opposed clamping edges extending the length thereof and being faced to engage conductors inserted through said casing back side, said terminal also including a prong engaging contact projecting from each of opposite ends of said terminal into said casing, a portion of said terminal intermediate said tongues and each of said contacts having an opening so that said terminal portion is reduced in lateral cross-section, and each of said tongues having a notch spaced longitudinally inwardly of each of said openings and extending inwardly from respective outer edges laterally opposite said clamping edges, the inward extent of said notches being suilicient to enable each of said tongues to pivot about a substantially longitudinal reference line extending through its notches and said openings, whereby the etect of bending moments on said tongues is localized.

6. A wiring device comprising an elongated casing of insulating material, an elongated generally rectangular and resilient terminal being supported Within said casing, a face side of said terminal extending longitudinally adjacent a back side of said casing, said terminal including a pair of conductor engaging tongues extending in the longitudinal direction and having opposed clamping edges extending substantially the length thereof and being faced to engage conductors inserted through said casing back side, said terminal also including an integral U-shaped Contact projecting from each of opposite ends of said terminal into said casing, one of a bight portion and an arm of each of said contacts being deflectable about respective lateral reference lines through said terminal, a portion of said terminal intermediate said tongues and each of said contacts having an opening so that said terminal portion is reduced in lateral cross-section, and each of said tongues having a notch spaced longitudinally inwardly of each of said openings and extending inwardly from respective outer edges laterally opposite said clamping edges, the inward extent of said notches being suicient to enable each of said tongues to pivot about a substantially longitudinal reference line extending through its notches and said openings, whereby the eiect of bending moments on said tongues is localized.

References Cited in the tile of this patent UNITED STATES PATENTS 1,582,957 Avery May 4, 1926 1,719,363 Gaynor July 2, 1929 1,977,487 Nero Oct. 16, 1934 1,986,652 Wack Ian. l, 1935 `2,228,683 Barrelle Jan. 14, 1941 2,396,725 Thomas Mar. 19, 1946 2,649,558 Franz Aug. 18, 1953 2,698,423 Modrey Dec. 28, 1954 2,748,363 Despard May 29, 1956 `2,773,248 Smith Dec. 4, 1956 2,873,433 Despard Feb. 10, 1959 2,875,424 Hubbell Feb. 24, 1959 2,890,436 Bentley June 9, 1959

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