US2451982A - Electrical plug and socket - Google Patents

Description

Oct. 19, 1948. E. l.. scoTT 2,451,982

ELECTRICAL PLUG AND SOCKET Filed Jan. s1, 1945 l N VEN TOR.

A TTU/WYE YS Patented Oct. 19, 1948 sfr-Ares PATENT .'o-F-Pic --ELECTRICAL"PLUG`AND' SOCKET .Eben L:.-Scott, Mission, Kans.

*Apl'ilicationJanuarySL 1945, 'Serial No."575,391

"Ihis invention relates.l -to electrical connectors, particularly-plug and-"socket membersfonuse in connecting various -`.appliances or 'the likefin anvelect'ric circuit andvhaslior itsprincipaloblject yto provide a' r structure-y Wherein the livefconf' tacts are asubstantially inaccessible'.l through the plugl inlet :ofl'the--socketr membenztherebyelimina-ting possibility Vof rshcrt `circuitsA .caused fby metal objects ibeing' thrustinto .thef socket.

Further objects of the inventioniareitocpro- -videea.connectorconstructed- :topreventl'accidenltal:ldisplacementioffthe plugw member by `pulling "or j erkingnon the:e1ectric cord connected'. thereto; .tolprovideia eplug and `socket :construction :which maintainspostive electrical :contactvvhen the lplugLLzisninsertedzin@,the ksocket for assuring 1 full :line zcurrentv tocan appliance.' served thereby.v and avoiding raros 'and rradio interferenceJ :ordinarily ,causedflby loose contacts; to provideva structure whereinxthwplug 'completely closes the socket opening :when:electrical contact :is :being-restab- .lishe`d; andf to: providefafconnec-torzfof relatively simple." and :inexpensive construction.

lIn .l accomplishing theseandzzother lobjects -of the invention las hereinafter; pointed out, `I have provided improvedstructure, the 4preferred.fo1m fof which isfillustratedfin. the'accompanying drawfing vwherein Fig- 1- is La? face View of :an electrical connector constructedi in accordance-with' the present .inven-tion.

.-rl'igiffZ isla -verticalusection throughthe con- Anector, part being shown in ,elevationA -toillustrate connection .of :anelectrcal service -wire thereto.

fFig... 3 is a fragmentary cross section on .the .line ',3--3 ,of Fig. r1 particularlyillustratingthe manner-of closing access to the livercontactswhen the ..plug member fis removedy .from the socket member.

. Eigeds. a perspective view..of,the .pa1ftsfof* the socket member shown in'disassembled spaced relation to 'better illustrate the "construction thereof.

Fig. 5 is a perspective viewof theplug member.

Figj 6-isa section througlroneof thel contacts ofV ltherplug Amember takenhon the linefiIf-f'b` f -of *Figi 5.

""Fig "7 `is a* horizontalsectionthroughf the connector onfthe line 'I-i'I v'of Fig.' 1'4 showing?. the'plug in position in the socket for establishing anz'electric'al fconnection.

' Re'ferring more rinV detail' to the :drawings:

l" Ivdesignatesan 'electrical' connectorv embodying the features of the presentixinvention-'zand l2 Claims. (CLN3-330) l2 which includes a sockety member 2 'and' a plug member'3. The socket memberZ"is/'preferably formed in two-sections fiend 5 `composed ofinsulatingmaterial such asa plasticthat is "read- :ily formable to -desired shape. The fmember 5` includes a body`6 havingy onelor Vmore preferably cylindrical recesses 'I openingl'fromaf'face side thereof but-l terminating short fof fthefopposite f ace9 to provide-'aninsulating lwall comjletelyfsurroun'ding :the lrecess.

`'Ihe connector 'illustrated vis ff'duplexf-type, fand, therefore, the member f 5 includes two'frecessesl located with their axes vin-parallel relation andfspacedapartby a constrictedfportion as best shown in Fig. 4. 'The outer contour-of they member 45 is preferably shaped `1.o..conforrn to the rec-essesand the-.sides .intermediatefthe recesses arecurVed inwardlylas rat` Illl to formt-the yportion@ `and-to a'ccommodate-terminalsv IIfzand :l2for` connectionfwith the leads 1.I3".of:an-e1ec tric circuitas later described.

Thezsection -I constitutes :a ycover?iorltheisectionzand isofia sizelto ,coverthefface side. 8 rof the'fsecticn and to .carry :theaterminals I I .zand I ZJSothatfthey. lieczad'ja'cent; the; curved 'faces I 0 and are contained within the .limits fofzthe" section 5.

In .the illustrated instance'the cover-'d isisubstantiallyV rectangular-,and has suicient thicknessxbetween the frontand rear faces'ILandl-IS .thereoilto thoroughlyainsulate'tcontact strips yI6 and I1 .andxprovide ample strength in resisting :pulling forces on an y'electric :cord connected therewith through'a plug Emeniber`3. The Aconl :tact strips IIE5-and IIarefdisposed' on opposite sides'ofxpluginletropenings I8 .vhiclizregster` with the recessesll. .The strips l i6 Aand'lly arewoffa -lengthLto intersectfrecesses I Sfand 2i] .formed `in- .Wardly :fromlthe 'rear faces VI5*,andvvhichfare spaced from'athefopenings` `I 8 toV provide sulcient insulating :material f 2 I f. therebetween for thoroughlyl insulating: the contact strips-rand prevent .anyxcontact therewith exceptfrom the direction ofthefrear; face I5-oi ,theicover member 4.' IIhe terminals IIzand` I2 are ipreferably integral 'with the xconta'ct 4strips and turned `laterally thererom''as: at'::22 to .project fromthe rearface I5 of; the lcoversection: a zsuiicient distance to accommodatefscrewsrfor connectionof the servicezawires :Hbf: anfelectric circuit ,asl yindicated in Fig.V 2. The openings` I8; have central cylindrical portions.' 2li.:locatedtcoaxiallywithy the; recesses.y 1 and J extending .therefrom sare ' notch portions 25 and 26. offless-fwidthttl-lan the .diameters-.0f `the cylindrical portions The notches have relatively parallel side faces 21 joined with arcuate faces 28 formed on a radius corresponding to the radius of the recesses 1. The recesses I9 and 2U, while being spaced from the inlet openings, are located within the limits of the recesses 1 as shown in Fig. 3.

It is thus obvious that the contact strips are exposed only through the recesses I9 and 20 and when the sections are connected together any access to the contacts must be attained from within the recesses 1 and from the rear face of the cover section 4. The cover section 4 carries ears 29 at the ends thereof for attachment of the' socket member within a conventional boxinot.

shown).

The ears 29 lare preferably formed of metal and have yanchoring portions 3U inset within recesses 3| provided 4on the rear face of the cover section 4 so that when the cover section is secured to the section y5 the anchoring portions are clamped therebetween -as shown in Fig. 2. 'I'he sections of the socket member are secured together by Ifastening devices such as screws 32 that extend through openings 33 in the cover section, registering openings 34 in the anchoring portions of the ears, land into threaded openings 35 formed in the section 5.

Contained within the recesses 1 are closures 36 for the plug 4inlet openings. The closures 36 are of disc-like form and of -a diameter to be freely movable axially of the recesses and to extend over the contact recesses I9 and 20 through which the contact strips I6 and I1 are exposed. The front Ifaces 31 of the closures conform to the rear face I5 of the front section 4' so that when engaged therewith there is no space occurring about the margin of the plug inlet openings. The closures are yieldingly retained in closing position by coil springs 38 also contained With-in the socket recesses 1 and having one end bearing against the bottoms thereof and their opposite ends against lthe rear faces of the closure discs, vas shown in Figs. 2 and 3, to urge the discs in A-closing position yand to establish positive pressure on the plug 3 for assuring positive contact with the contact strips.

The plug 3 includes a substantially cylindrical body 39 of substantially the diameter of the cylindrical portion of the inlet openings and having laterally extending lugs 49 and 4I diametrical'ly arranged with respect to each other yas Vshown in Fig. 5. The lugs 40 and 4I have fiat side faces 42 (Fig. 5) to ypass between the faces 31 of the notch portions 25-26 and arcuate end faces 43 to pass Ibetween the arcuate faces 28 of the notches so that Ithe plug is readily insertable through either one of the inlet openings of the cover section when the lugs on the plug are aligned with the notch portions of one of the openings. The cylindrical lbody portion of the plug has an axial bore 44 opening therethrough and which `intersects a transverse groove 45 provided in the rear face of the lugsas shown in Fig. 5. Formed in each lug and extending from the bottom of the recesses to the outer faces 46 of the lugs are openings 41 (Fig. 6) mounting meta'l bushings 48 having internally threaded openings 4'9 therein to mount contacts 50 having face portions 5I adapted to engage the exposed portions of the contact strips through the recesses I9 and 20. The faces 5I of the contacts are, therefore, spaced a slightly greater distance from' the front faces of the lugs than the depth of therecesses as'sh-own in Fig. '1 so as to assure contact. The

threaded openings also mount screws I52 that have the shank portion 53 inserted from lthe opposite ends of the bushings with the heads 54 positioned within the transverse groove. The electrical cord 55 yis passed through the boss of the plug land the conductors therein are extended laterally through the groove to be anchored by the screws 52` to the contacts.

In assembling a socket member constructed as described, the springs 38 yare inserted in the recesses 1 of the section 5 followed :by the closure :plates 36. 'The ears 29 Iare then applied to the ends of the cover section 4 so that the anchor portions 30 thereof lie within the recesses 3|. The cover section 4 is then applied over the face side of the section 5 with the terminals I I and I2 passing over the sides of the section `5. The screws 32 are then inserted to complete the assembly of the socket element. The leads I3 form an electric circuitand are connected by the screws 23 with the terminals II and I2 and the socket element is pushed into the box for lattachment therein as in conventional manner. 'Ihe box is then preferably covered by an ornamental cover plate 56 of conventional design except that the plug openings 51 thereof conform in shape to the inlet openings of the cover section 4. The cover plate 56 is secured in position by a fastening device 58 extending through an opening thereof and engageable in a threaded -opening 59 in the cover section.

In using the connection, the plug 3 is inserted into one of the openings I8 by holding it in position so that the lugs 4I and 42 thereon register with the notch portions 25 and 26 of the opening. When in registering position, the plug is pushed through the opening so that it bears upon the closure disc 36 and additional pressure on the plug moves the disc 36 away from seating Contact with the rear face I5 of the cover section 4. When the contacts have cleared the cover section the plug is rotated to bring the lugs thereon in registry with the recesses I9 and 20. Then, upon releasing pressure, the stored up tension in thecoil spring 38 presses the disc 36 against the plug and effects suicient outward movement thereof for the contacts to enter the recesses I9 and 29 and engage the contact strips I6 and I1 thereby making a positive electrical connection with the electric circuit to which the connector is attached. When thus engaged, it is impossible to remove the plug without exerting sufficient pressure in opposition to the spring 38 for moving the contacts out of the recesses I9 and 20. Even then, it is necessary to rotate the plug to bring the lugs thereon into registry with the notch portions 25 and 26 of the inlet openings before the plug can be removed. As the plug is removed, the spring urges the closure disc in following contact with the end of the plug so that by the time the plug completely closes the inlet opening and is being withdrawn therethrough, the closure plate seats against thev inner face of the cover section and this is before the plug has been removed from closing relation with the opening. From the foregoing itis obvious that I have provided an electrical connector of simple and relatively inexpensive construction that is safe and dependable and which cannot be short circuited by objects accidentally inserted into the socket.

It is also obvious that when the connection is made the plug member cannot be accidentally removed by pulling or jerking upon the cord connected therewith.

What I claim and desire to secure by Letters Patent is:

1. In a device of the character described, a socket element having a recess therein, insulating means covering said recess and provided with a plug inlet opening including a circular portion substantially coaxial With the socket and substantially oppositely arranged radial notch-like portions, said insulating means having seating faces at the sides of the circular portion and facing said recess and having contact exposing recesses within and completely surrounded by said seating faces, contact elements within said insulating means and exposed through said recesses in the seating faces, a closure member in said socket-like recess and having marginal portions contacting the face portions completely around the contact exposing recesses to completely cover the exposed portions of the contacts, and a coil spring in the socket recess and bearing substantially circumferentially of said marginal portions for urging the closure member into contact with said seating faces.

2. In a device of the character described, a socket element having a recess therein, insulating means covering said recess and provided with a plug inlet opening including a circular portion substantially coaxial with the socket and radial notch-like portions, said insulating means having seating faces at the sides of the circular portion and facing said recess and having Contact eX- posing recesses within and surrounded by said seating faces, contact elements Within said insulating means and exposed through said recesses in the seating faces, a closure member in said socket-like recess and having marginal portions contacting the face portions completely around the contact exposing recesses to completely cover the exposed portions of the contacts, a coil spring in the socket recess and bearing substantially circumferentially of said marginal portions for urging the closure member into contact with said seating faces, and a plug member having a head conforming to said circular portion of the plug -inlet opening and having radially directed lug portions adapted to pass through the notch-like portions When the closure member is depressed against action of the spring and having contact elements for substantially lling said contact exposing recesses, said lugs having marginal portions surrounding the contact elements to close said contact exposing recesses when the plug member is in position in the socket element.

EBEN L, SCOTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,509,889 Kuhn Sept. 30, 1924 2,102,625 Hubbell Dec. 21, 1937 2,230,658 Stull Feb. 4, 1941 2,312,017 Ackerman Feb. 23, 1943 FOREIGN PATENTS Number Country Date 27,585 Great Britain (1903) Feb. 25, 1904

Images