US3437976A - Swiveling connector for electric cord - Google Patents

Description

R. A. NELSON SWIVELING CONNECTOR FOR ELECTRIC CORD April 8, 1969 Sheet Filed May 11, 1967 Fig.3

INVENTOR.

Russell A. Nelson BY W WW Attorneys A ril 8, 1969 R. A. NELSON SWIVELING CONNECTOR FOR ELECTRIC CORD Sheet Filed May 11, 1967 INVENTCR. Russell A. Nelson. BY %wwz 6 g Attorneys United States Patent Int. Cl. H01! 35/00 US. Cl. 339-8 6 Claims ABSTRACT OF THE DISCLOSURE A female electrical connector having holes to receive stiff prongs of a plug is rotatable about a rigid supportmember having a plurality of axially spaced contacts (e.g., like a multi-conductor plug) and contains resilient leaves situated to be contacted directly by said prongs and to bear against said contacts; the rear end of the support member is connected to an electrical circuit, e.g., a flexible cord, stiff prongs forming a plug, or, when embodied in a convenience outlet fixture, wires fast to a base to which the connector is fixed. The connector is in the form of a housing which is rotatable relatively to the support member and its electrical circuit by antifriction means, such as a ball bearing ring.

The invention relates to a multi-circuit swiveling connector having a female housing for receiving the prongs of an electrical plug and a part therein which is rotatable relatively to the housing and adapted to be connected to an electrical circuit. The invention may be embodied variously as a connector interposed between two flexible electrical cables, plugged into a standard convenience outlet, as in a building wall, or may itself constitute such a convenience outlet.

It is a common problem that electric cords attached to appliances of various kinds become twisted during manipulation of the appliance. In an attempt to overcome the problem it has been proposed to provide a swivel in or at one end of the cord. Such swivel devices have, however, not been fully satisfactory for various reasons, such as cost of manufacture, unreliability in effecting electrical connections between several conductors, or, in some instances, a limitation on the number of conductors that can be accommodated. Thus, a third circuit is sometimes desirable to provide a ground, and even more than three circuits need to be so connected in specialized applications.

The instant invention provides a multi-circuit swiveling connector that can be interposed between sections of a cord or at one end thereof, e.g., be plugged into a convenience outlet or be constructed as a convenience outlet, which is economical and simple and can be constructed to make a dependable electrical connection between pairs of conductors or between triplets or between larger groups of conductors.

In summary, according to the invention the connector includes a housing having an end wall of insulating material that is rotatable relatively to a rigid support member which is situated at the axis of the housing, the support member having near the end wall a plurality of contact elements situated at axially spaced points and having external surfaces of revolution that individually make contact with resilient leaves that are carried by the housing and are positioned in relation to openings in, the said end wall so as to be slidably engaged by the prongs of a plug that are inserted through said openings.

In a preferred construction the leaves are carried by the end wall of the housing and normally do not make contact with (or make uncertain contact with) the contact elements, but are pressed against these elements when pressed inwardly by the prongs of the plug.

The rigid support member, which may be formed as a 3,437,976 Patented Apr. 8, 1969 Ice conventional telephone plug, provides a plurality of con ductors which are connected to an external circuit at the rear of the support member. When the swivel connector is to be interposed between sections of a flexible cable, one section is connected to the plug and the other to the condoctors of the support member, which may then be situated wholly within the housing. When the swivel connector is to be plugged directly into a convenience outlet, a pair of, or more than two stiff prongs are attached to the conductors at the rear of the support member. When the swivel connector is to constitute a convenience outlet, the support member extends rearwardly from the housing and is rigidly secured to a base which is mounted at the rear to a wall of a recess or box.

It all embodiments the rigid supporting member is preferably mounted for rotation within the housing by antifriction means, such as a ring of ball bearings.

The invention will be further described with reference to the accompanying drawings forming a part of this specification and showing three illustrative embodiments, wherein:

FIGURE 1 is an elevation view of the swivel connector as applied between sections of flexible electrical cord;

FIGURE 2 is a longitudinal sectional view of the connector of FIGURE 1, parts being shown in elevation;

FIGURE 3 is a sectional view of a second embodiment, adapted to be plugged into a female connector;

FIGURE 4 is an end view of a third embodiment, in the form of a recessed convenience outlet;

FIGURE 5 is a sectional view taken approximately on the line 55 of FIGURE 4, parts appearing in elevation, and

FIGURE 6 is a fragmentary sectional view taken on the line 6-6 of FIGURE 4 showing only parts of the connector.

Referring to FIGURES 1 and 2, the swivel connector includes a housing including sections 10 and 11, each having integral therewith a half of a front end wall 12 situated at its front (right) end. These sections can be united in any desired manner, as by screws 13 or by bonding with an adhesive or polymerizing resin. The housing is formed of electrically non-conductive material, e.g., molded from a synthetic insulating resin. The rear end has a second or rear end wall 14 having a central opening in which is fitted a rotatable, flanged bushing 15, which may be made of metal and has a loose fit so as to rotate easily relatively to the housing. The front end wall is formed as a female connector, and to this end has two openings 16 extending therethrough, spaced and shaped to receive the stiff metallic prongs 17, 18, of a plug 19 which is connected to the end of a flexible twoconductor electric cord 20. The rear face of the wall 12 is recessed between the openings 16, as shown.

The front end wall 12 is formed with grooves opening into the openings 16 for retaining the in-turned front ends of resilient leaves 21, 22. These grooves, as well as the openings 16, are formed partly in each housing section 10, 11 so that the leaves can be slid into one section edgewise before attaching the other section. It will be noted that the leaf 21 is shorter than the leaf 22 and that both are bowed away from each other near their front ends so as to make sliding contact with the prongs 17 and 18, respectively. The rear ends of the leaves are bent inwardly and again outwardly, as shown at 23, to bear against contacts to be described.

The housing is fixed to an outer bearing race 24 by means of a pair of radial walls 25, and is freely rotatable relatively to an inner race 26 to which it is secured by a ring of ball bearings. The inner race or ring is fixed to a rigid support member which includes axially spaced, mutually insulated contact 27 and 28 having external 3 surfaces of revolution. The support member may be constructed like a conventional multi-conductor plug as shown, also known as a coaxial plug, and then the part 27 is a metallic tube forming one conductor and containing a concentric second conductor which is connected to the ball-like tip 28, the latter being separated from the tube by an insulating ring 29. The support member is fixed to the inner race 26 by any suitable means, as by bonding with an adhesive; it can also be fixed to the inner race through a bushing 30 formed of insulating material. Electrical contact to an external circuit is made through angled lugs 31 and 32 which are separated by an insulating washer and make electrical contact respectively with the tube 27 and the concentric conductor which is connected to the tip 28. These lugs are connected, as by soldering, to the circuits of a flexible electrical, multiconductor cord or cable 33, and the connection may be encased in insulating material 34, such as a potting resin. The cable 33 extends out of the rear end of the housing through the bushing 15 and is attached to a male plug 35 which can be inserted into a convenience outlet 36.

In operation, when the parts are connected as appears in FIGURE 1, the housing -11, plug 19 and parts secured nonrotatively thereto can rotate relatively to bushing 15, the rigid support member 27-2-8, cable 32, and parts secured non-rotatively thereto. Insertion of the prongs 17, 18 engages the leaves 21, 22 to deflect these leaves toward each other and presses their rear ends against the contact elements 28 and 27, respectively. Upon rotation of the housing relatively to the support member these leaves rotate about these contact elements, making a dependable electrical contact while offering only a negligible resistance to the rotation. The bushing assumes the angular position of the rigid connector and cord 33 and offers no significant opposition to rotation.

Referring to FIGURE 3, there is shown an embodiment in which all parts bearing reference numbers 1030 (except 15) of the first embodiment are used in similar form. The support member 27-28 is connected to stilf metallic prongs 37, 38, which have bent lips at their front ends, these lips being separated by an insulating washer 39 and making electrical contact with the tube 27 and the concentric conductor 40, respectively, the latter conductor being attached to the tip 28. When the housing sections are interconnected by screws a third screw 41 at the rear may be provided in this embodiment.

Operation of the second embodiment is as described for the first, with the difference that the prongs 37, 38 are inserted into a female connector, such as the outlet 36 described for the first embodiment. The housing is rotatable about its axis relatively to the prongs 37, 38 and the support member 27.

As was previously indicated, the invention is not limited to the interconnection of circuit pairs, but can be used to interconnect additional circuits, by employing additional leaves which make contacts with additional prongs of a plug and with additional contacts on a support member.

In the third embodiment, shown in FIGURES 4-6, the connector is in the form of a convenience outlet, which can be mounted in recessed relation in a wall. An optional feature shown is a third circuit which may, for example, establish a ground. The connector is mounted within a metallic box 50 providing at its rear a base plate 51 of insulating material, and having a central internally threaded projection which receives a long screw 52 for securing a cover plate. In the embodiment shown the outlet provides two swivelled female connectors, both of which are independently rotatable relatively to the base.

Each of the two connectors includes a housing including sections 53 and 54, of insulating material and formed with a front end wall 55, corresponding to the wall 12. In this embodiment the wall has two principal openings 56 and 57 for receiving the electrically conductive prongs 17a, 18a, of a plug 19a, and a third opening 58 for receiving a third prong 59 which orients the plug to the housing and may be used for a ground circuit, the cord 20a then having three wires. The positioning lug may be used with a two-wire cord, merely to adapt the connector to direct current. The connector includes resilient springs 21a, 21b, outer and inner ball bearing rings 24a and 26a, all constructed as previously described for the first embodiment. The construction differs in the following respects: The central support member provides three contacts, of which the tip contact 28a and a front ring contact 60 are in contact with the front portions of the leaves 21a and 22a, respectively when the plug 19a is inserted. These contacts are separated by insulating washers 61 and 62 from each other and from a metallic tube 63 which constitutes a third conductor and which is electrically connected to the inner ball bearing race 26a, which is fixed thereto by any suitable means, such as bonding with a resin, deforming metal or soldering. The outer bearing race 24a is inserted from the open lower end of the housing against a positioning wall 25a, being retained by bonding. This race makes electrical contact with a metallic conductor 64 which is recessed in a groove in the housing section 53 and is secured by bonding. The conductor has, at the front end, an in-turned radial section providing an axial part 65 which is resilient and is engaged slidingly by the prong 59. (When no ground circuit is to be provided, the parts 58, 64 and 65 are omitted, and the support member is constructed as was described for the preceding embodiments.)

The supporting element extends rearwardly beyond the open rear end of the housing and is fixed to the base plate 51. Electrical connections to the three conductors of the support member are made by metallic conductors 67, 68 and 69, which are connected respectively to the coaxial lead 70 to the tip contact 28a, to the intermediate tubular conductor 71 to the second contact and to the outer tube 63. These conductors are of stiff sheet material and carry connecting screws 72, 73 and 74, to which stationary wires are connected.

FIGURE 5 shows at the right a possible position of the leaves 21a, 22a, out of contact with the contacts of the central supporting member when no plug is inserted. At the left of this view a plug 19a is shown to be inserted into the housing, whereby its prongs 18a and 18b press these leaves inwardly toward each other and against the contacts 28a and 60, respectively. This action is the same in the previous embodiments. The ground circuit from the prong 59 is made via the conductor 64, the races 24a, 26a, tube 63, conductor 67 and screw 72.

Whether or not a plug 19a is attached, the housings are freely rotatable about the central, rigid support member, because the friction between the ends of the leaves against the contacts is slight.

I claim:

1. A multi-circuit swiveling connector comprising:

(a) a housing having at its front end a transverse wall of electrically insulating material and formed with a plurality of openings extending axially therethrough for receiving stifi metallic prongs of an electrical plug,

(b) a plurality of resilient metallic leaves extending axially within the housing and secured therein, said leaves being positioned for slidable engagement by individual prongs,

(c) a rigid support member having a plurality of conductors situated within said housing and mounted for rotation relatively thereto, said member having at its front end a plurality of contact elements which are situated at spaced axial positions and are electrically connected to said conductors, each of said contact elements having an external surface of revolution, said leaves being shaped to engage a different one of the contact elements, and

(d) means for attaching a multi-conductor electrical circuit to the respective conductors of the support member.

2. A connector according to claim 1 wherein at least some of said leaves are secured at their front ends to said end wall at positions relative to said openings to be engaged with resilient deflection by said prongs at their outer sides, the rear ends of said leaves being in external engagement With said contact elements, whereby the pressure of said prongs presses the leaves against the contact elements.

3. A connector according to claim 1 wherein said means for attaching a multi-conductor electrical circuit includes a flexible electrical cable containing a plurality of metallic conductors connected respectively to the conductors of the support member at the rear end thereof, said cable extending out of the rear end of the housing and being rotatable relatively to said housing.

4. A connector according to claim 1 wherein said means for attaching a multi-conductor electrical circuit includes a pair of stiff metallic prongs extending out of the rear end of the housing and being relatively rotatable to said housing, said last-mentioned prongs being secured at their front ends to the rear of the support member for rotation therewith and connected electrically to the conductors of 20 the support member.

'5. A connector according to claim 1 wherein said connector is constructed as a wall outlet and includes a base situated in rear of said housing, said support member projecting rearwardly from said housing and being fixed to said base, whereby said housing is rotatable relatively to the base.

6. A connector according to claim 1 wherein said rigid support member is mounted to said housing by anti-friction means including a race of balls.

References Cited UNITED STATES PATENTS 2,069,126 1/1937 Asklund 3398 2,248,759 7/1941 Hollander 3398 2,582,800 1/1952 Sorenson 3398 FQREIGN PATENTS 213,330 5/ 1941 Switzerland.

RICHARD E. MOORE, Primary Examiner.

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