US 2294608 A
Description (OCR text may contain errors)
Sept. l, 1942. w. A. RUDoLPHsEN ELECTRICAL CONNECTOR Filed sept.' 3. 1940 Patented Sept. l, 1942 ELECTRICAL CONNECTOR Walter A. Rudolphsen, Richmond, I nd., assignor to Belden Manufacturing Company, Chicago, lll., a corporation of Illinois Application September 3, 1940, Serial No. 355,168
My invention relates, generally, to electrical connector means for conductor cords, and it has particular relation to electrical attachment or connector plugs having spring type contact prongs.
It has been previously found that in many instances connector' plugs having the standard type plain at projecting contact prongs, failed to couple with or become attached to associated receptacles or sockets with sufficient retentive force to prevent their pulling or dropping out. This-fault or defect was usually due to the prongs becoming bent out of the alignment in which they are originally provided, or becoming otherwise worn. To overcome this difculty and objection, connector plugs have been provided, the contact prongs of which have different spring arrangements intended to give a tighter connection and greater coupling force. spring type connector or attachment plugs however, have not proved to be entirely satisfactory in certain respects. The object of the present invention is to provide connector plugs of the spring terminal type which are materially superior to the prior art connector plugs in certain important features as will appear hereinafter.
More specifically, an important object of my invention is to provide connector plugs of the spring contact prong or blade type having all free ends on the contact prongs or blades enclosed in the body part of the plugs. That is, there are no exposed or outside 'free ends on the contact prongs of my improved connector plugs. Another important feature combined with this free-end enclosing feature, isl that in my improved connector plugs the spring portions of the contact prongs receive partial support from the resilient body members as will appear hereinafter.
The above important objects, and certain further objects and advantages of the invention will be made more apparent on reference to the accompanying drawing and the following detailed description of one preferred embodiment thereof.
In the drawing:
'Fig 1 is a fragmentary, partially vertical sec-A tional view of a connector plug embodying the novel features of the present invention;
Fig. 2 is a fragmentary, partially vertical s'ectional view taken on one side of the connector or attachment plug shown in Fig. l;
Fig. 3 is a side elevational view of one of the contact prongs or blades of the plug shown in Fig. l;
Fig. 4 is an elevational view taken on one edge of the contact prong shown in Fig. 3;
Such prior plug I 0 comprises a resilient body member II- having a relatively large cavity in the front end thereof and a hole in the rear end through which a conductor cord I2 may be inserted. The particular body member II shown is somewhat at in shape and may be molded from a suitable rubber composition. It will be understood that the body member II may be made in certain other suitable shapes, and from certain other materials. The body member II serves. to support a pair of contact prongs I3 which project in parallel alignment from the front end thereof. The prongs I3 are formed from flat strips of conducting metal such as copper or certain copper alloys, and comprise a projecting portion I4 and an inner support portion I5. The prongs I3 are inserted in the body member Il and t against the sides of the front cavity or opening therein with 30 the innermost ends thereof fitting tightly in a .pair of recesses I 6 in the rear portion of the body member II. 'Ihe conductors I1 of the conductor cord I2 are connected to the contact blades I3 by buttons I8 of solder flowed into apertures pro- 35 vided in theenclosed ends I5, as shown at I9.
'I'hese solder connections serve to retain the contact prongs I3 in place when the' connect-o1; plug I0 is pulled from a receptacle with which it has been connected.
I3 in proper spaced apart relationship, and to also close the cavity in the front end of the body 20 andserves to separate the 'conductors II in L the cavity in the body member II, as shown in Fig. 1. The insert 20 may be formed of suitable material, s uch as molded rubber, and it may In order to help' maintain the'contact bladesI tween the tongues 25 and the main part of the projecting portions I4. These spring tongues 25 are bent out from the contact prongs I3 and are shaped into three different portions 26, 21 and 28, as indicated. The portion 28 is relatively long and slants out from its integral connection with the outer end of each contact prong I3 at a small angle with the main fiat part thereof. The spring tongues 25 then straighten out into relatively short at sections 21, andthe rear or free ends 28 of the tongues 25 are bent back towards the contact prongs I3, as shown. It will be understood that the spring tongues 25 do not have to conform closely to the particular shape described but may vary somewhat. However, the shape shown and described has been found to be particularly satisfactory.
When the contact prongs I3 are tted into place in the body member II with the bent out spring tongues 25 facing each other, and the insert Ais inserted therebetween, the inner free ends 28 are enclosed within the front end of the plug I0. The end walls 30 of the insert member 20 are slanted to conform to and it the inclined free portions 28. The projecting ends I4 of the contact prongs' I3 are normally parallel to each other andspaced apart a distance corresponding to the separation of the socket openings in a standard receptacle.
receptacle 3I is shown with spaced apart terminal or socket openings 32 therein. The receptacle This arrangement is shown in Fig. 1 of the drawing where the front end of a bear similarly against the outer sides of these 3I may be of any suitable standard type. The
front ends of the contact prongs I3 are projected in broken lines to show that the openings 32 in the receptacle 3l` are somewhat wider than the thickness of the tip portions of the contact prongs I3. In Figure 1 it will be noted that the distance T from outside the spring tongue portions 21 to the opposite side of the prongs I3 is substantially greater than the width of the openings 32. The edges of the openings 32 are beveled as shown to make foreasier insertion therein.
In Fig. 5 of the drawing, the connector plugl I0 is shown with the contact prongs I3 part way inserted into the receptacle 3|. In the position shown, -the slanting portions 26 of the spring tongues 25 are bearing against the inner sides of the terminal or socket openings 32, and the front ends of the contact prongs I3 have engaged the Aspring terminals 33 of the receptacle 3l. As the connector plug II) ispushed further in towards the receptacle 3l, th spring tongues 25 continue to be wedged or forced against the inner sides of the openings 32, thereby spreading apart the contact prongs I3 from their parallel alignment.
In Fig. 6, the connector plug I0 is shown completely pushed in with its front end against the receptacle 3l. As will be noted, the receptacle terminals 33 have been considerably bent back with the outer ends I4 of the contact prongs I3 bearing fiatwise thereagainst. Thestraightened out portions 21 of the springtongues 25. bear iiat against .the inner sides of the socket openings 32, while the main flat part of the contact prongs I3 ,is inserted in the receptacle 3|.
openings 32. It will be noted that the inner free ends 28 of the tongueshave been forced into the openings formed in the outer ends I4 of the contact prongs I3 by cutting and bending out the spring tongues 25 and have distorted or laterally stretched the body member II as indicated at 34. The resistance of the body member I I against the distortion at points 34 serves to partially support the spring tongues 25 when the connector plug I0 The spreading of the contact prongs I3 and the wedging of the spring tongues 25 in the socket openings 32 serve to tightly couple and connect the connector plug I0 to the receptacle 3|. Repeated and extended use of the connector plug I0 does not substantially alter this strong coupling arrangement. Also, the flat parts of the outer ends I4 of the contact prongs I3 bear flatwise against the terminals 33 of the receptacle 3| with a greater than normal contact force, thereby providing improved vents the catching and the distortion of the tongues through accident and use. And, las noted, the distortion or lateral stretching of the rubber or resilient body member II by the inner free ends 28 serves to partially support the spring tongues 25.
Since lcertain changes may be made in the foregoing construction and different embodiments of my invention may be made without departing from the principle thereof, it is intended that all matter described hereinbefore or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense, and that the accompanying claims shall be accordedthe broadest construction permitted by the prior art.
I claim the following as my invention:
1. An electrical connector plug of the class described, comprising, in combination, a body member of resilient stretchable material, a pair of fiat contact prongs supported at their inner ends within said body member and projecting outwardly therefrom, each of said prongs having an integral free-ended cut-Out spring tongue extending rearwardly from the outer end thereof and bent out of the plane of the prong to lie at a small angle thereto; the rear free .end portions of said tongues lying within the front end of said body member and adapted to thrustingly engage opposite sides of said body member when pressed intowards their respective prongs, said pressing in of the spring tongues being effected by a sliding wedge engagement of said tongues with the socket openings and being opposed by the combined spring resistance of said tongues and the resistance to stretching of said body member acting on the free ends of said tongues.
2. An embodiment of claim l, wherein the free end portions of the tongues lying within the front end of the body member are oppositely inclined to project toward the opposite sides of the body member so as to have a biting engagement with the latter when the prongs are fully inserted in a socket member.
3. An electrical connector plug of the class described, comprising, in combination, a body member of resilient stretchable material formed .with a central cavity in its front end and a pair of recesses in its rear portion, a pair'of flat spring metal contact prongs having their rear ends tightly tted in said recesses and projecting beyond the face of said body member, each of said prongs having an integral free-ended cut-out tongue extending rearwardly from the outer end thereof and bent out of the plane of the prong to lie at a small angle thereto; the rear free end portions of said tongues lying within the front end of said body member and adapted to thrustingly engageopposite sides of said body member when said prongs are fully inserted in a socket member, and a removable one-piece plug inserted in and closing said central cavity of the body member and having opposed surfaces forming abutments for the inner sides of said free end portions of the tongues.
4. An embodiment of claim 3, wherein the freeend portions of the tongues lying within the front end of the body member are inclined to project toward the opposite sides of the body member, and the opposed abutment surfaces of the plug are correspondingly inclined.
5. An electrical connector plug of the class described, comprising a body of resilient material, and a pair of parallel at spring metal prongs embedded in and projecting forwardly of the face of said body, said prongs having cut-out longitudinal tongues integral at their outer ends with the outer ends of said prongs, and said tongues being shaped to provide inwardly inclined portions adapted to have sliding wedge engagement with the inner walls of socket openings, intermediate portions parallel with saidV prongsl adapted to lie flat against said inner walls when the plug is fully inserted in the socket member, and outwardly inclined free end portions disposed within the plug body and adapted to be forced into gripping engagement' with opposite sides of the plug body by the wedging action of said inwardly inclined portions and to be held in such engagement by the i'lat contact of said intermediate portions lwith the inner walls of the socket openings. Y
. WALTER A. RUDOLPHSEN.