US 2498643 A
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Feb. 28, 1950 Filed March 27. 1946 FQG. BELLEK ELECTRICAL RECEPTACLE 2 Sheets-Sheei'l l INVENTOR.
Feb. 28, 1950 F. G. BELLEK 2,498643 ELECTRICAL RECEPTACLE Filed Maron 27, 1945 2 sheets-sheet 2 62 '/0 67 l Z6 a 62 Ng-Ns INVENTOR.
Patented Feb. 28, 1950 ELECTRICAL RECEPTACLE Frank G. Bellek, Chicago, Ill., assignor, by direct and mesne assignments, to Bell Electric Company, Chicago, Ill., a corporation of Illinois Application March 27, 1946, serial No. 657,415
The present invention relates to electrical receptacles and to certain improvements in the construction and arrangement of parts of the invention disclosed in my application Serial No. 645,883, which application is incorporated herein by reference.
Observation has revealed the fact that the life of receptacles is very short when they are subjected to continual use as where household appliances are plugged in and detached repeatedly. It is seldom possible to determine what receptacles will be used the most in a house, or elsewhere, and for that reason it is seldom that heavyV duty receptacles or extra receptacles are provided at. any particular point. Consequently, the eiective life of receptacles in a house would appear to be the life of the most used ones, i. e. the time of use before repair or replacements started. Most of the failures incurred arise from broken contacts or spring contacts that are sprung beyond their elastic limit due to repeated use or twisting of the plug prongs in the receptacle sockets. This occurs primarily because, working in such close quarters, the spring contacts are formed of complicated stampings bent to complex forms without suiliclent body length for the springs for them to give when depressed by a prong without exceeding their modulus of resiliency. Double springs have also been used where the displacement caused by insertion of a plug prong is divided between two opposing springs. However, due to the looseness developing between the receptacle and plug in repeated use, the prongs can easily be wiggled enough in getting them started that one or both of the two springs can be distorted or displaced sufliciently that good electrical contact is not possible without repair or replacement of the receptacles.
Some manufacturers have sought to overcome this difliculty by providing spring action prongs,
*1-5"@ a receptacle which will accommodate such a spring within the conventional receptacle size.
A further object of the invention is to provide a spring element providing contacts for the two Y sockets of a duplex receptacle where the spring action incurred at one socket is carried throughout more than a half of the spring element.
A further objectof the invention is to steady rest one face of a prong insert against the receptacle body and have a full acting spring contact displaced under controlled conditions which prevent any distortion weakening the 'spring Another object of the invention is to support the spring against displacement longitudinally of the prong with a supporting action which permits lateral movement of the spring contact at the support point when flexed by insertion of a plug prong so that resiliency in the spring element beyond the support pointis eiective when electrical contact is established.
' The'invention is further characterized by an arrangement whereby the receptacle can be connected to the house wiring in either one or both of two ways with a single clamp screw for each side of the line.
but this only serves as a temporary correction the plug is pulled out with the appliance load` still on..
It is one of the objects of this invention to correct for these diiculties and to provide a spring contact which will retain its working position and tension under all prong conditions and provide It is also van object of the invention to provide a receptacle whose parts and construction are strong and rugged, inexpensive to construct and assemble, and more efficient and enduring in operation.
` These being among the objects of the invention, other and further objects will appear from the drawing, the description relating thereto and the appended claims.
In the drawing:
Fig. 1 is a plan view of a duplex receptacle embodying the invention as it appears when mounted in place ready for use, with one of the sockets in use. Y, Fig. 2 is a plan view of the duplex receptacle lfrom the rear thereof with its back cover removed and a house wire connected to the contacts.
Fig. 3 is a side elevation partly in section illustrating the manner in which the metal mounting strip and backy cover are assembled with the main body of the receptacle.
- Fig. 4 is a section taken upon line 4-4 of Fig. 3. Fig. 5 is a section taken upon line 5 5 of Fig. 2.
,.Fig.' 6 is a longitudinal sectional view similar to Fig. 3 illustrating another form of the invention. "l Figi 7 is a side'elevation .partly in section illustrating the Vpreferred formy of the linvention.
i If desired, a'nipple 51 can be provided at the time the incline 5l is made. lSuch a nipple would engage in the hole usually provided in the prongs of conventional plugs. However, this is not necessary for the purpose usually intended -for the p rong holes because the binding action provided between the guard I 2 and the base I0 as exterted by the guard spring 58 will tend to hold the prongs in place. The nipple would preferably serve as a locating means for the prong to position it properly in place at the effective center of the spring contact end 56.
With this construction of the spring contact, the contact cannot be strained beyond its resilient limit, yet is simple, easily and inexpensively formed, being an element that provides improved electrical contact with a plug prong.
The spring contact is supported loosely in place at the bends 52 and 53 by upright elements 60 and SI Aformed integrally in the base. The ilexure load on the spring ends 56 are carried by these elements, while the spring band as exteriorly exposed at its middle is supported by elements 46! on opposite sides of the screw 41 against pressure exerted by a screw driver engaging the screw. v
j In connecting the receptacle to the house wiring, the ends of the wires are skinned of insulation a short distance, the screw 41 loosened, the bare'ends of the wire inserted a short distance vthrough the holes 48 and the screw tightened down to bend the wire iiat and hold the end 'thereof in the hole 48. This manner of securement' is very simple, and as many wires can be connected to the spring contact as there are holes around the screw. Thus the receptacle can serve as a connector station if desired. In event, however, only one Wire is to be connected to each spring contact, the usual loop can be made around the screw if desired and the screw tightened in place to hold it.
If desired the elements B0 can be connected to the adjacent walls 21 by a reinforcing rib 1I. Greater strength would be provided and the screw 41 would be separated from the spring end portion of the recess 46. This would also prevent the remote possibility that enough wire would be pushed through the opening 48, or be broken off, to interfere with the operation of the spring contact ends.
The back cover 40, as shown in Fig. 3 preferably closes the recesses, and covers the strip 26. To do this. the edges of the cover follow the border of the base and are provided with locating bosses 62 which follow the curves 63 at the ends of the recesses 46. These bosses are flat on their exposed face to serve as pads supporting the spring contacts at the band 55 against displacement by prongs which have difficulty in riding the incline 5I. The pad, however, permits full flexure of the spring contact laterally.
Recesses 64 may also be provided to receive the upper ends of the elements 60 to support them if desired and when the cover is fastened in place by the screws 31 the receptacle is fully enclosed by insulating material and ruggedly rigid for handling and use.
In event, it is desired to locate the strip 26 outside of the cover, the cover can be held in place as shown in Fig. 6 by a tubular tie 6G which is upset as at 61 beyond the strip to rivet it in posi.- tion, and upset at the other end as at 6B for securement on the base l lia. The inside of the tube is threaded as at 10 to receive the face plate screw 32 (Fig. 1).
Consequently, having thus described several embodiments of the invention and the reasons for thepreferred formsshown, it will be readily apparent to those skilled in the art of manufacturing and using electrical outlet receptacles that the objects and purposes of the invention are attained, and that a duplex receptacle is thus provided which is simple and inexpensive to make that a minimum of parts are used, most of which are duplicating elements for manufacturing economy; and that the parts as formed can be formed by the simplest of production machinery. v'I'he spirit and substance of the invention are commensurate Iwith the scope of the appended claims. I
' What is claimed is: il'. In a receptacle, a base provided ywith integral wall structures joined, at their ends to denetwo recesses extending the length of the base, said base `havingprong ,receivingl openings opening into" the Vvtwo recesses adjacent the separating walls, spring contacts mounted in said recesses extending lfrom one end of a recess to the other end, each spring vcontact comprising a metal strip having a threadedopening near its middle exposed outside the recess between two wall ends, said strip being symmetrically formed on'opposite ends to have upset edges forming an incline and the ends of the ystrip being reversely bent to dispose thev inclines oversaid openings with the in'- lclines between the openings and the remainder` of the strip, said strip being lformed adjacent its middle to rest against saidwali' ends to flex at these points under displacement by plug prongs received throughsaid openings which displacement moves the overlapping portions of the reversely bent ends away from said separating walls, and means upon said body for holding said .spring contacts in position against said wall ends the spring contacts being unsupported and free to flex throughout the overlapping portions.
2. In a receptacle the combination including a body having a prong receiving opening therein and a wall adjacent one side of said opening, a
prong contacting member rigidly mounted withl respect to said wall at a point remote from said mening, said member extending from said point 'o a second point on the other side of said opening and the end portion thereof being bent backwardly so as to terminate over said prong receiving opening, and an inclined edge on said end portion, said edge being inclined toward the portion extending across said prong receiving opening forming a cam surface which cooperates with a prong to cause said member to be bent away from said Wall when said prong is inserted therebetween.
3. In a receptacle the combination including a body having pairs of prong receiving openings therethrough, a wall adjacent one side of each of said openings, ,aj pair of prong contacting members rigidly mounted on said body at points remote from said openings, said members extending from a prong receiving opening of one pair to a prong receiving opening of the other pair and the end portions thereof vbeing bent backwardly so as to terminate over said prong receiving openings, and an inclined edge on each end portion, said edges being inclined toward the portions extending across said prong receiving openings, forming cam surfaces which cooperate with prongs to cause said members to be bent away from said wall when said prongs are inserted therebetween. f
4. In a receptacle, -a base provided with integral wall structures joined at their ends and defining agee-,us
tworecesses extendingthe length of the base, said base having prong receiving vopenings opening into the -two recesses' bordering the separating walls-spring icontacts mounted in the two recesses and having :reverse `bends therein located 'at the ends of the recesses, and inclined cam faces on the reversely bent portions vcooperating with prongsy received through said openings to move the contacts away from the walls as the prongs are inserted, and means for mounting the springs in said recesses permitting flexure of bothsides of the Voverlapping portions of the contacts in one direction only under the displacement of said prongs.
5. In an electrical outlet receptacle, a body having prong receiving openings therethrough, and a spring contact comprising 'a metal strip having 'means near its middle for attaching a conductor thereto, said strip being symmetrically formed on opposite ends of its middle in that the end portions of the strip are reversely bent parallel to the strip and ythe reversely bent .portions having an edge upset to form an incline, the inclined edges sloping towards the intermediate portions, said strip being shaped between said bends to .be received in supported relationship in said receptacle body, the strip being free to `flex throughout its overlapped portions, and the inclined edges being disposed behind the prong vreceiving openings, and the prong contacting surfaces of said strip being located on the reversely bent portions thereof and on the side remote from the intermediate portions of the strip.
6. In a 4recptacle, the combination including a body having a prong receiving .opening therein, a prong contacting member rigidly mounted onsaid body `at a point remote from said opening, said member extending from said point to a second point on the other side of said opening and the end portion thereof being bent .backwardly so as to terminate over said prong receiving opening, and an inclinedy edge on said end portion,` said edge being inclined toward the portion extending acrosssaid prong receiving opening formingv a cam surface which cooperates with a. prong. to cause said member to be moved away froms'ad opening when said prong is inserted therein, the side of said end portion of the member making electrical contact With the side of said prong when the latter is fully inserted,
, FRANK G, BELLEK.
REFERENCES CITED The following references are of record inthe le 7of this patent:
UNITED STATES PATENTS Hutt Aug. l0, 1943