US 3838381 A
This safety current outlet and plug device is preferably of the continuous type, i.e. constituting a kind of skirting-board along a wall or the like. The electric contact between the prongs of the cap, plug or connector and the electric conductors of the current outlet is obtained by causing the elastic deformation of the prongs consisting to this end of a very flexible conducting and elastic metal blade of very reduced thickness, for instance of the order of 0.1 to 0.3 millimeter, of which the front portion is adapted to engage a rigid surface of the female member which produces a substantial deformation of said blade which is sufficient for ensuring a satisfactory and reliable electric contact between said blade and an electric conductor inserted in said current outlet.
Claims available in
Description (OCR text may contain errors)
| o i u 41 United States Patent [1 1 De Villemeur SAFETY OUTLET AND PLUG DEVICE  Inventor: Philippe De Villemeur, Maisons Alfort, France  Assignee: Etablissements A. Gregoire et L.
Barilleau, Maisons Alfort, France  Filed: June 28, 1973 ] Appl. N0.: 374,357
Related U.S. Application Data  Continuation of Ser. No. 125,777, March 18, 1971,
Pat, No. 3,777,300.
 Foreign Application Priority Data Mar. 19, 1970 France 70.9881
 U.S. Cl. 339/21 R, 339/62  Int. Cl H0lr 9/00  Field of Search 339/20, 21 R, 21 S, 22 T, 339/23, 24, 59, 60, 61, 62, 63
Primary Examiner-Bobby R. Gay Assistant Examiner-Robert A. Hafer Attorney, Agent, or Firm-Amster & Rothstein  ABSTRACT This safety current outlet and plug device is preferably of the continuous type, i.e. constituting a kind of skirting-board along a wall or the like. The electric contact between the prongs of the cap, plug or connector and the electric conductors of the current outlet is obtained by causing the elastic deformation of the prongs consisting to this end of a very flexible conducting'and elastic metal blade of very reduced thickness, for instance of the order of 0.1 to 0.3 millimeter, of which the front portion is adapted to engage a rigid surface of the female member which produces a substantial deformation of said blade which is sufficient for ensuring a satisfactory and reliable electric contact between said blade and an electric conductor inserted in said current outlet.
Thus, a current outlet may be obtained wherein any direct access to anyone of its conductors is positively prevented when using a rigid member, so that a safety current outlet is obtained.
2 Claims, 10 Drawing Figures Pmmtbsmmm SHEET 3!)? 5 PAIENIEB SEP241974 SHEEI'QW 5 mmgusmmm 3..38.381 saw 5 w s SAFETY OUTLET AND PLUG DEVICE This application is a continuation of application Ser. No. 125,777 filed on Mar. 18, 1971, now US. Pat. No. 3,777,300.
BACKGROUND OF THE INVENTION The present invention relates in general to connectors and like wiring devices and has specific reference to an outlet and plug device of the type comprising in general a female member or outlet and a male member (cap or plug), wherein the quality of the electric contact obtained is due to the resilient pressure exerted by one of these members against the other; in these devices the resilient action is provided either by a resilient female member, so that when the male member is introduced into it it moves the lips of the female member slightly away from each other whereby the female member bears resiliently against the male member. or to the provision of a slightly resilient male member, so that, during its penetration into the female member, the latter exerts a lateral pressure causing a slight elastic deformation of the male member; alternatively, both members may have a certain resiliency in order to con- SUMMARY OF THE INVENTION It is the essential object of the present invention to provide an electric outlet and plug device of the type broadly set forth hereinabove wherein the electric contact between the plug cap blades and the electric conductors of the current outlet is obtained by elastic deformation of said blades each consisting to this end of a relatively thin strip of conducting and resilient metal, about 0.1 to 0.3-millimeter thick, for example, which is extremely flexible and adapted to engage with its front or free end a rigid surface of the female member so as to cause a substantial deformation of said blade which is sufficient to ensure a satisfactory and reliable electric contact between said blade and an electric conductor ofsaid current outlet; now, copper while having a sufficient conductivity has a poor elasticity, so that it is ill suited for making such plug blades; therefore, these blades may be made of beryllium bronze.
The current outlet may be so designed that no direct access can be had to anyone of its electric conductors, so that a safety current outlet is obtained, the considerable permissible deformation of said blades enabling them to reach these conductors otherwise inaccessible to conventional plug blades and also to any other object unless it is extremely flexible; besides, the moderate thickness of these blades permits of reducing to less than one millimeter the width of the access slots to the conductors incorporated in the outlet, so that the safety is increased correspondingly.
Each plug blade may be so designed that its deformation resulting from its introduction into the female member is also attended by the locking of the blade within the outlet; alternatively, this blade may be designed to constitute the female member of another current outlet adapted to cooperate with the blade of another cap or plug.
Of course, on the basis of the general arrangement set forth hereinabove, many other forms of embodiment may be contemplated.
Thus, notably, in case the elastic deformation of this thin blade, as a consequence of the specific shape of the female member intowhich it is engaged, were not sufficient for efficiently pressing this blade against the conductor disposed in the bottom of said female mem ber, a double blade may be used which consists of a loop having a relatively short radius of curvature and two arms of which the portions extending on this side of the loop engage with a sufficient pressure the walls of a constriction formed in said female member and adapted to produce a relatively pronounced deformation of said arm portions.
The current conductor may consist of a thin copper section, for example less than 1 millimeter thick, having a cross-sectional configuration matching that of the cavity provided beyond the access slot of the current outlet, so as to bear against, and closely accommodate the contour of, said bottom, after this conductor has been introduced through said access slot.
Thus, it is possible to manufacture underextremely economical conditions current outlets in the form of skirting-boards having a continuous access slot and consisting of an extruded plastic strip, associated with electric conductors of the type set forth hereinabove and inserted into the cavity of said plastic strip as described in the foregoing.
The amount of plastic material and metal necessary for manufacturing this skirting-board and the corresponding plugs or connectors is extremely reduced, and the assembling step can be performed instantaneously without using any tool.
BRIEF DESCRIPTION OF THE DRAWING The attached drawings illustrate diagrammatically by way ofexample two typical forms of embodiment of the present invention. In the drawings:
FIG. I is a cross-sectional view showing on a relatively large scale a first form of embodiment with the blades of the plug or cap about to be inserted into the current outlet;
FIG. 2 is a fragmentary perspective view showing a short section of the current supply conductor before the insertion thereof into the current outlet;
FIG. 3 is a view similar to FIG. 1 but showing the cap blades fully engaged into the current outlet;
FIGS. 4 and 5 illustrate a modified form of embodiment wherein the blades of the cap or connector are double or looped, before and after their engagement into the current outlet, respectively;
FIG. 6 is a sectional view showing a current outlet and cap assembly, the two component elements of the device being separated from each other;
FIG. 7 is a view similar to FIG. 6 but showing the two component elements in their assembled or contact position',
FIG. 8 is a perspective view showing a blade utilized in the male member;
FIGS. 9 and 10 are similar views of modified forms of embodiment of this blade.
DESCRIPTION OF THE PREFERRED EMBODIMENT.
The current outlet illustrated in FIG. 1 is of the skirting-board type providing a continuous inlet; it comprises a relatively thin strip 1 of plastic material, obtained by extrusion, in which a pair of channels 2,3 are formed; these channels 2,3 having a substantially curved configuration are inclined at a considerable angle in relation to the front face 4 of the strip or outlet, and the width of their access slots 5, 6 is less than one millimeter; just beyond these slots 5, 6 the concave wall 7 of channels 2, 3 comprises an inner shoulder 8; at a point intermediate this shoulder 8 and the bottom 9 the convex and concave walls 10, 7 of each channel comprise other shoulders 11 and 12, as shown; electric conductors 13 for example of the type illustrated in FIG. 2 are fitted in the bottom of these channels; these conductors comprise to this end thin conducting metal blades forming at one end a loop 14 of same radius as said channel bottom 9 and having two arms 15, 16 each formed with an outflaring concave portion 17, 18 corresponding in shape to the curved intermediate portion of said channels 2, 3; at their opposite ends these blades comprise longitudinal edges 19, 20. It is clear that this thin section can easily be introduced through the access slots 5, 6 of the current outlet illustrated in FIG. 1, and the elasticity of their arms 15, 16 is sufficient for causing them to resiliently engage the wall of the rear portions of said channels, so that the longitudinal edges 19, 20 fit closely against the shoulders 11, 12 acting as convenient means for safely locking the conductors in their operative position.
The plug cap or connector illustrated in FIGS. 1 and 2 comprises a small plate 21 of plastic material in which the rear portions 22, 23 of a pair of very thin blades 24, 25 of conducting and elastic metal are embedded; to this end, these rear ends are looped as shown at 26, 27 and engage a pair of bores 28, 29 provided to this end in said plate 21 and opening laterally; at a short distance from the front face of plate 21 these blades 24,25 are bent to constitute a pair of resilient locking projections 31,32.
In the case of a connector, the device is complete in the form described hereinabove, provided that the distance between the bores 28 and 29 corresponds to that prescribed for the blades or prongs of a conventional and standard cap, which can be introduced into these bores for engaging the loops 26, 27 of blades 24,25 and thus provide the desired electrical connections.
Whether in the case of a plug cap or a connector, the device operates as follows: When the cap or connector is approached to the front face 4 of the skirting-board, and the two blades 24,25 are firstly inserted into the access slots 5 and 6 of the pair of channels 2 and 3 of said striking-board, then pushed home until the front face 30 of the plug cap engages the registering front face 4 of said striking-board, the blades 24,25 are subjected to a strong elastic deformation as a consequence of their engagement with the concave face 7 of said channels, and the outer ends of these blades subsequently ensures an efficient elastic contact with the electric conductor 13, and notably by resiliently engaging its conducting arm 15; simultaneously, the projections or loops 31 and 32 have undergone a deformation as a consequence of their passage through the access slots 5 and 6, and immediately after this passage the blades 24,25 expand again and are thus locked behind the shoulders 8.
To remove the cap or connector and cut or switch out the current, it is only necessary to release the projections 31, 32 by slightly lifting the cap or connector,
so that the blades 24 and 25 can easily be extracted from the outlet.
The modified form of embodiment illustrated in FIGS. 4 and 5 differs from the preceding one in that there is a direct access to the electric conductors so that the elastic deformation to be exerted on the blades for reaching the conductors in the first form of embodiment is suppressed; thus, in order to exert a similar elastic pressure against these conductors. the blades consist of a loop 35 and two arms 36, 37, the blade thickness being thus reduced and being even inferior to 0.2 millimeter; the electric conductors may consist, as in the preceding case, of a conducting metal section 38 having a cross-sectional shape corresponding substantially to that of the section element of the preceding form of embodiment, except for the fact that section 38 is symmetrical. Furthermore, the access slot 39 is also symmetrical with two shoulders 40, 41 adapted to retain and lock the ends 42,43 of the two arms 44, 45 of metal section 38; the double blade may also comprise within the plastic base plate 46 a pair of half-loops 47 and 48 which are fitted in bores 49 and 50 and adapted to constitute, in the case of a connector, the female members engageable by the plugs or prongs of a conventional cap.
In the alternate form of embodiment illustrated in FIGS. 6 to 8 the skirting-board is very much similar to that shown in FIGS. 1 and 2, but in this case the caps or connectors and notably their metal blades are somewhat modified. In fact, the front portion of these blades 51 comprise three successive curved portions 52,53 and 54 having opposite directions as in a corrugation, the last curved portion 54 being however somewhat more pronounced than the other two. Moreover, on this side of the curved portions each blade comprises a pressed portion 55 which, as clearly shown in FIG. 7, constitutes a locking element adapted to retain the connector or cap 56in its electric contact position with respect to the conductor of cap 57; the rear portion of each blade 51 shown more particularly in FIG. 8 is adapted to constitute on one side a partly cylindrical half-shell 58 having an outflaring opening 59; on the other side, it comprises an extension 60 having substantially the same width, which is bent on itself transversely through 180 about a fold line 61, the edge of this extension being adapted to constitute another partly cylindrical half-shell 62 complementary to and registering with the first half-shell 58, and also formed with an outflared inlet opening 63.
In the alternate form of embodiment illustrated in FIG. 9, the lateral portion 76 of blade 51 comprises only one outflared rear edge 77 adapted to facilitate the contact with the prong when the latter is introduced into the connector; in addition, a lateral portion 78 of part-cylindrical configuration may be provided for constituting a complementary contact line with the prong.
It is clear that when blades thus shaped are fitted in any connector such as the one illustrated at 56 they can constitute the female member of an outlet, adapted to receive the prongs 64 of a cap (not shown), even if these prongs differ considerably from one another.
The current outlets 57 may consist of skirting boards formed with longitudinal slots 65 of a width preferably inferior to l millimeter so as to allow just the corrugated portions 52,53, 54 of blades 51 thercthrough and permit their ingress into channels 66 having a considerable upward and inward inclination, and limited on one side by a surface 67 having its concavity directed outwards and on the other side by a surface 68 having its concavity directed inwards; these surfaces 67 and 68 are provided with shoulders 69 and 70 respectively permitting the locking of U-shaped electric conductors 71 of which the arm 72 having an outwardly directed concavity is considerably longer than the arm 73.
Thus, when it is desired to plug in this connector by inserting the blades 51 through the slots 65 of the current outlet, these blades 51 engage firstly the rigid surface 68, with an inner concavity, of channel 66, so that the blades are deflected towards the bottom of the channel until, having slipped on this surface, their curved portion 54 engage the arm 73 of the electric conductor and their curved portion 53 engage the other arm 72 of the same conductor; thus, a very efficient and reliable contact is established; in contrast thereto, if it is attempted to insert a rigid member through the thin slot 65 of the current outlet, this member is positively prevented from contacting the electric conductor.
As shown in FIG. 7, when the connector is fitted in position its pressed projections 55 resiliently engage the inner lower edge 74 of slot 65, thus locking the connector in position.
To facilitate the manufacture of these skirting-boards 57 each channel 66 thereof may comprise on the side opposite to its surface 67 a small chamber 75; if desired, the slots 65, instead of being formed by extrusion, may be obtained subsequently by a simple sawing operation.
Thus, these skirting-boards may conveniently be manufactured as a continuous strip, by extrusion, by utilizing a conventional extruder.
FIGS. 6 and 7 also show that for each electric conductor of the current outlet the connector comprises a single metal member acting jointly as a male member and as a female member; this single metal member is secured and retained within the connector without resorting to any metal fastening member, in contrast to the conventional design of hitherto known connectors; if the connector casing consists of a two-piece structure and if these pieces are assembled by mutual snap-fitting engagement, their arrangement is such that this snapfitting action ensures at the same time the locking in position of these single metal members corresponding each to one of the current outlet lines.
Of course, the forms of embodiment described hereinabove with reference to the accompanying drawings should not be construed as limiting the scope of the invention since many modifications and variations may be brought thereto without departing from the basic principles of the invention as set forth in the appended claims; thus, notably, locking means for retaining the blades of the cap or connector in the current outlet, similar to the means illustrated at 8, 31, 32 of the first form of embodiment could be provided as well in the second form of embodiment; likewise, although the above description refers mainly to current outlet conductors consisting of a thin copper section, it is clear that a thin, suitably treated aluminium section could be substituted therefor.
What is claimed is:
l. A safety outlet and plug device of the continuous access type comprising electrically coacting outlet means and plug means, said outlet means including at least two spaced and substantially parallel curved channels of generally arcuate configuration, said channels each being in different planes and curving in the same direction, each of said channels being formed with a closed bottom at one end and a thin slot at the other end, a conductor formed of a thin strip of resilient metal lining the closed bottom of each said channels, said conductor having a U-shaped configuration and the ends of said conductor being flared outwardly, each of said channels having shoulders formed therein and engaged by said flared conductor ends for retaining said conductors in said respective channels, said plug means including at least two spaced and substantially parallel curved strips of elastic metal having a generally arcuate configuration, said strips each being in different planes and curving in the same direction, said parallel curved strips having a greater radius of curvature than said parallel curved channels so that said parallel curved strips may be simultaneously inserted within said parallel curved channels.
2. A safety outlet and plug device in accordance with claim 1 wherein each of said channels and each of said conductors includes a concave face and a convex face, the difference in the radius of curvature between said strips and said channels being large enough to cause said strips, upon being inserted into said respective channels, to slide along the concave faces of said channels and, upon being fully inserted, said strips engage a substantial portion of the concave faces of said conductors with an elastic force which insures the desired electrical contact between said strips and said conduc-