US 2762026 A
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Description (OCR text may contain errors)
Se t. 4, 1956 F. K. KNOHL ELECTRICAL CONNECTOR Filed March 5, 1953 an" 1L3 United States Patent ELECTRICAL CONNECTOR Friedrich Karl Knohl, Chicago, Ill., assignor to Illinois Tool Works, Chicago, 111., a corporation of Illinois Application March 5, 1953, Serial No. 340,513
3 Claims. (Cl. 339-192) This invention is concerned generally with an electric socket construction and more particularly with a clip forming a female electrical connector and its cooperating insulating housing.
In many applications of plug-and-socket electrical connectors such as for ranges, clothes dryers, water heaters, and many other uses, rather substantial currents must be handled. In many prior connectors, substantially only line contact has been made between the male and female connectors. This gives rise to heavy current densities causing overheating of the connectors, burning and pitting along the lines of contact, and generally short service life.
All electrical connectors must have some sort of insulated housings and must be mounted in such housing in some manner. The best insulations from the standpoint of electrical non-conductivity and heat resistance are ceramics. Unfortunately, ceramics are not very strong physically and are prone to cracking and chipping if they are mishandled. In spite of the physical weakness of ceramics, they often must be used due to their superior electrical and thermal characteristics. This poses a difficult problem of properly mounting the connectors in their insulated housings without damage to the housings or danger of displacing the connectors from the housings.
In the prior art female connectors with which I am familiar the contacting surfaces have been normally spring loaded into engagement with one another to secure positive gripping contact with male connectors. This often has made insertion of male connectors difiicult, has tended to dislodge their cooperating connectors from their respective housings, and has resulted in only line contact between the male and female connectors.
The general object of this invention is to provide a new or improved electrical socket construction.
A further object of this invention is to provide a socket construction wherein the female connector has a large contact area.
Another object of this invention is to provide a socket construction wherein the female connector has contacting surfaces which are parallel to one another when engaging a male connector.
A more specific object of this invention is to provide, in one form of my invention, an improved socket construction wherein the female connector has contacting surfaces which at all times are substantially parallel.
A further object of this invention is to provide a socket construction having a female connector into which a male connector may be inserted with utmost ease.
Yet another object of this invention is to provide a socket connection having improved and simplified means for mounting a female connector in an insulating hous- This invention contemplates achieving the foregoing objects and other objects and advantages by the provision of a socket construction wherein a female connector is mounted in an insulating, preferably ceramic, housing. The connector is provided with opposed contacting sur- 'the T-shaped cross section lying on the outside.
Patented Sept. 4, 1956 Ice faces of considerable extent which, in one embodiment of the invention, are substantially parallel throughout their extent at all times, either with a male connector inserted or not, and in another embodiment are spring biased toward one another and are urged into parallelism by a male connector for large surface area contact therewith. The large, parallel contacting areas insure adequate contact with a male connector, while the parallelism of the surfaces, coupled with their normal parallelism in operation, facilitates insertion of a male connector into the female connector. The female connector takes the form of a clip which snaps into place in a recess in an insulating housing without the necessity of any fasteners which would tend to chip or crack a ceramic housing. The female connector is provided with portions bearing against the insulating housing which positively maintain the contacting areas substantially in parallelism with a male connector inserted.
Other and further objects and advantages of the present invention will be apparent from the ensuing description when taken in connection with the accompanying drawings, wherein:
Fig. 1 is a plan view partially in section and with certain parts broken away illustrating my improved socket construction and a plug cooperable therewith;
Fig. 2 is an end view of the socket construction as taken along the line 2-2 of Fig. 1;
Fig. 3 is a cross-sectional view of the socket construction with a plug about to be inserted thereinto, and taken along the line 3-3 of Fig. 1;
Fig. 4 is a View similar to Fig. 3 showing the plug in fully inserted position with the male and female connectors in cooperative engagement;
Fig. 5 is a cross-sectional view through the socket taken along the line 55 of Fig. l; and
Fig. 6 is a perspective view of the female connector.
Referring now in greater particularity to the figures, and first to Fig. 1, there will be seen my improved socket construction 10 and a plug 12 cooperable therewith. The socket construction 10 includes an insulating base or housing 14 preferably formed of ceramic material such as porcelain. The ceramic base or housing 14 is substantially T-shaped in cross section as may be seen in Figs. 3 and 4. The major portion of the housing is adapted to be inserted into an aperture in a wall or the like 16 with the peripheral flange 18 forming the arms of The flange 18 is provided with a plurality of recesses 20 for accommodating the heads of screws 22 or the like which extend through the flange 18 and into the wall or the like 16 for mounting the socket.
The ceramic or insulating housing 14 is provided with a plurality of parallel, elongated openings 24 which extend through the housing from front to back and are generally rectangular in cross section as may be seen in Fig. 5. The openings 24 are provided at their front ends with projections or teeth 26 having beveled front edges 28 for facilitating insertion of a male connector, and having square shoulders 30 at the rear thereof for retaining the female connector in place as will be apparent later.
Each opening 24 is further enlarged by a pair of longitudinal grooves or recesses 32 extending throughout a substantial portion of the length of the openings 24. The grooves 32 along with the restrictions at the front ends of the openings formed by the teeth 26 impart a cross-shaped appearance to the openings when viewed from the front of the socket as in Fig. 2.
The female electrical connectors fit in the apertures 24 and are generally designated by the numeral 34. Each connector 34 is made of sheet metal, preferably stainless steel, and comprises a U-shaped portion having parallel side walls 36 interconnected by a bight portion 38. As
r 2,762,026 V Y may be seen in Figs.'3- and 4 and the walls 36 are adapted to abut. the, corresponding interior surfaces. of. the apen tures 24.
The walls 36 continue integrally as diagonally inward- 1y directed sections-"38, which in turn continue integrally as parallel, spaced apart arms 40 adapted'toembrace-the male connectors asv will be apparent hereinafter. The outer ends of the arms 40 are outwardly deflected as at 42 and are adapted to abut both the shoulders 30 to position the connector 34 in its corresponding opening 24 and the side wall of the. opening to prevent spreading apart of the arms 40. i
A pair of rearwardly extending spring legs 44 is struck out of the arms 40. The 'legs44 at'theforward ends thereof are integral with the deflected portions- 42 of the arms and diverge outwardly therefrom in a smooth curve asat 46. The legs 44- reach ar'naximum separation at 43- atwhichpoint they are spaced apartslightly greater than the width of an opening 24. The. legs then curve inward ly again as at 50, and finally outwardly to from free tips or end sections 52. V
The legs 44 project part way into the grooves 32. while the free tips or end portions 52v abut the shoulders formed between the grooves 32 and the sides of each opening to' prevent retraction of a connector after it has.
been inserted into its corresponding opening 24. The/ complex curved configuration of the legs 44 insures that the ends 52 thereof will stand outwardly of' the walls 36 for firm anchoring of the connector 34 in place without having the ends .52 urged 'apart with such great force as to make insertion of the connector'into its. correspondingopening-24 of the housing 14 difficnlt age the housing;
The bight portion 38 of the connector 34 is. formed with a central opening 54 having an extruded section or neck 56 surrounding it and provided .on its inner surface with screw threads for receipt of a screw 58. adapted I to clamp a connecting wire 60 against the bight portion 38 of the connector. The free edges: of each bight portion 38 preferably. are. formed with rearwardly directed flanges 62 (omitted from the front edge in Figs; 3 and 4 for clarity of illustration) to prevent the wire .60 from moving outwardly from beneath the head of the screw 58.
In Figs. 1, 3, and 4- there is shown a plug 12 cooperable with the socket 10. The plug 12 comprises a ceramic or other insulating base or housing 64 carrying a plurality of sheet metal prongs or electrical connectors 66 which likewise can be formed of stainless steel. The male conor likely to damnectors 66 are in the form of flat strips of material which may be straight throughout their extremities or which.
may be twisted 90 as illustrated at 68, It will be understood that the female connectors 34 are oriented similarly to the male connectors 66. Twisting'or rotating one or more pairs of cooperating connectors insures that the plug 12 can be plugged into .the socket 10 in only one possible position, thus insuring proper connections. I
The male connectors or prongs. ,66 are provided. with dimples or struck out portions 70 (Figs. 3 and 4) fitting in recesses 72 in the insulating housing 64 and which may serve to aid .in positioning the male connectors in the housing. The housing 64 is provided with suitable recesses 74exposing the rear ends of the male connectors or prongs 66. The rear ends are suitably apertured and threaded for receipt of screws 76 for anchoring .connecting' wires 78. 2
Ceramic products such as the housing herein disclosed cannot always be controlled economically to very close tolerances in production. Accordingly, I have found that it is sometimes necessary or desirable toform the clip or female. connector to compensate for individual variations in housings. A clip of this type is shown in Fig. 1 with apart of the housing broken away for clarity of illustration. This clip or female connector is generally identified by the numeral 34a and is similar to the con Hector previously disclosed except that the arms 40a are angled toward one another. When the connector 34:: is
inserted in housingme legs. 44a, which diverge from.
the arms 40a more than in the previously disclosed embodiment, bias the arms 40a toward one another to bring.
them into line contact at the bases of the outwardly deflected arm portions 42a. When a male connector is inserted the arms 40a are spread into parallelism against the spring force of the legs, 44:: so that a large surface area of contact is obtained substantially independently of the size of the opening 24 in the housing;
It will be seen particularly from an inspection of Figs.
3 and 4 that the parallel arms 49 provide a large area of contact with the male connector, thus positively avoiding burning, pitting, and general overheating. The initial configuration of the. female connector 34 is such that only the flexible legs 44 need be temporarily deformed in sliding each of the female connectors into its corresponding opening 24 in the base or housing 14, and these legs do not exert. a. suflicientoutward force to tend to damage. the
housing during the insertion. After insertion, the legs 44a. in one embodiment of the. invention bias the. arms; into line contact, while in the other embodiment the legs. 44 do not: exert a sutficicntoutward force to tend'to force the arms 40.v toward one. another out of parallelism. In
both forms of :the invention the dimensions. of the .con-
nectors are chosen so that. they and the abutment of the:
walls 36 and the outwardly deflected arm portions 42:v againsttheinterior walls of each opening 24 tend to main-.-
tain. thev arms 40. and 40a in parallelism with a male connector 66 inserted. between them and spreadinggthem apart very slightly.
' The beveled: front surfaces 28, of the. teeth26 serve to centralize each .male connector 66 to a considerable; extent, while. the outwardly deflected arm ends. or portions. 42 complete :the centralization. 1 Comparatively little effort; is needed in inserting av male connector. Thev out-- ward'ly deflected tips .52. of the legs 44 prevent. movement of a female connector fromits opening or recess; during insertion of a male connector while the outwardly deflected armsor tips 42 prevent movement. of
lating housing having an .elongated opening-therein, said housing, further havingv apairrof elongated recesses lying along oppositesidcs of saidopening and in open commun cation therewith, said.v recesses being shorter than said. opening and forminginterior shoulders therewith, a
pair of oppositely disposed projections on said. housingextendingriuto said opening at the front thereof and having outer beveled surfaces facilitatingv insertion of a male connector into said opening, said projectionsv having interior shoulders arranged oppositely of the recess. shoulders; and a femalezconnector' in said opening, said connector being in the form of a sheet metal clip having means providing opposed substantially fiat contact sur- 7 I faces, said contact surfaces normally being parallel to one another and adapted toengage a cooperating male connector over a substantial area, said contact surface defining means having outwardly diverging ends engaging behind said projection shoulders and engaging opposite walls of said opening, a pair of parallel side wall portions spaced .apart'farther than said contact surfaces and en gaging the opposite walls of said opening, and being connected to the means providing the contact surfaces by diagonal brace portions, the parallel walls and outwardly diverging ends engaging opposed walls of said opening I maintaining said contact surfaces at all times in parallel:
ism, and a pair of spring members struck from the means providing the contact surfaces and extending sinuously outwardly therefrom in said recesses and having outwardly extending free ends engaging said recess shoulders, the free ends engaging said recess shoulders and the outwardly diverging ends engaging said projection shoulders anchoring said female connector in said opening.
2. An electric socket construction comprising an insulating housing having an elongated opening therein, said housing further having an elongated recess lying along one side of the opening and in open communication therewith, said recess being shorter than said opening and forming an interior shoulder therewith, a pair of oppositely positioned projections on said housing ex tending into said opening at the front thereof and having outer beveled surfaces facilitating insertion of a male connector into said opening, said projections having interior shoulders arranged oppositely of and confronting the recess shoulders, and a female connector in said opening, said connector being in the form of a generally U-shaped sheet metal clip having substantially flat leg portions providing parallel, opposed, contact surfaces adapted to engage a cooperating male connector over a substantial area, said female connector having outwardly diverging ends on the fiat leg portions engaging behind the projection shoulders and engaging opposite walls of said opening, a pair of substantially flat leg portions between said contact surfaces and the bight of said female connector positioned farther apart than the contact surface providing flat leg portions and interconnected therewith by diagonal leg portions, the second mentioned pair of flat leg portions engaging opposite walls of said opening and coacting with said outwardly diverging ends to maintain said contact surfaces at all times in parallelism, and a spring member struck from one of the legs of the female connector, said spring member being attached to one of the outwardly diverging ends and extending outwardly therefrom and back along a contact providing leg portion into engagement with the recess shoulder, whereby, in cooperation with the outwardly diverging ends engaging the projection shoulders to anchor said female connector in said opening.
3. A female connector as set forth in claim 2, wherein the bight is provided with flanges on its margins projecting in a direction away from the flat leg portions behind the projection shoulders which serve to reinforce said bight portion, and with an aperture for receipt of a screw for clamping a connecting wire against said bight between said flanges.
References Cited in the file of this patent UNITED STATES PATENTS 1,700,831 Downing Feb. 5, 1929 1,841,736 Jones Jan. 19, 1932 2,034,966 Weich Mar. 24, 1936 2,223,231 Smith Nov. 26, 1940 2,259,207 Hunt Oct. 14, 1941 2,296,631 Doane Sept. 22, 1942 2,360,917 Wade Oct. 24, 1944 2,384,287 Drury Sept. 4, 1945 2,664,552 Ericsson et al. Dec. 29, 1953 2,691,147 Sutton et al Oct. 5, 1954