Patent Publication Number: US-10312640-B2

Title: Magnetically activated power socket and plug combination

Description:
BACKGROUND 
     Field of the Technology 
     The invention relates to the field of electrical power connectors without axially extending prongs or probes and which connectors are activated by a magnetic force. CPC H01R13/7037 
     Description of the Prior Art 
     Conventional power connectors comprise of a male plug component having contact prongs extending axially or longitudinally outwards for insertion into a corresponding receiving member in a female plug component or a socket, where the receiving member mechanically holds the prongs in place and the male and female plug components are electrically connected using frictional force. The susceptibility of conventional designs to tampering by children or inadvertent contact with the conducting prongs is legend with an estimated number of instances of at least 2400 children each year being severely shocked or burned with a dozen fatalities by insertion of metallic objects into the sockets or inadvertent touching of the prongs. 
     Some prior art designs employ shutters in the socket which only allow two prongs to be simultaneously inserted. However, these designs are often difficult to manipulate and still do not render the socket tamperproof. 
     A number of designs have been proposed to lessen the chance of electrocution by tampering some of which employ a magnet to activate the electrical contacts and to couple the plug to the socket, such as shown in US Patent Application 2016/0336695. However, such designs incorporate magnetically actuated power switching circuits, which increase the cost of the design and its long-term reliability and robustness. 
     In addition to the problem of tamper proofing a power plug and socket, there are general disadvantages to conventional prong and socket systems. In most instances two-prong plugs are unidirectional with one prong being wider than the other. For such plugs it sometimes hard to tell which way the plug needs to be oriented to plug in. This invites inadvertent contact with the prongs. 
     A three-prong plugs is sometimes hard to plug in because all three prongs must simultaneously engage the corresponding sockets. It is common in a three-prong plug to break the grounding prong. Often users actually break the grounding prong off intentionally to accommodate a nonconforming outlet or extension cord. 
     Bent prongs need to be straightened out in order to be successfully used, again inviting unintended contact with a live prong. Pulling on a connected power cord, such as by a vacuum, can bend the prongs, and possibly break the outlet. 
     It is not uncommon for a socket to lose its resilient fit over time such that the plug is too loose, falls out or causes arcing. 
     New receptacles on the other hand can be hard to plug in or to unplug, if the clearances are small and the socket is tight. If a socket is not mounted correctly, it can be pushed into the wall or junction box resulting in possibility of malfunction. Pulling a plug by its wire can break the connection to the plug on the inside causing it to malfunction, or even rip out the cord from the plug. Pulling it sideways, bends the prongs or could break the outlet. 
     User often find it hard to plug in a cord into a socket located behind an object or piece of furniture, thus leading the user to try to feel the prongs and inviting inadvertent contact with a live prong. 
     What is needed is a design for an electrical socket and plug that avoids each of the disadvantages of the prior art. 
     BRIEF SUMMARY 
     The illustrated embodiments of the invention include a magnetically actuated electrical power socket and plug system. The plug includes a plurality of conductive ring contacts provided on the face of an insulating cylindrical plug body. In the center of the plug body is a permanent magnet around which the ring contacts are disposed. In the illustrated embodiment a three wire plug is described, but any number of wires could be accommodated within the design. 
     A socket module is provided which has an insulating fixed face in which there are a corresponding plurality of fixed conductive contacts in the face. The face contacts are normally inactive or without electrical power. Behind the fixed face and spaced therefrom is a movable ferromagnetic transfer bar carrying a corresponding plurality of insulatively isolated transfer contacts aligned with the face contacts. The transfer bar is carried or positioned within the socket module by a plurality of extension springs, which normally maintain the transfer bar spaced apart from the face. 
     The transfer contracts are wired or electrically coupled to a corresponding plurality of fixed conductive terminals extending from the rear of the socket module. The fixed terminals are conventionally coupled or can be wired to conventional three wire house wiring or conventional electrical power circuits. 
     When the magnetic plug is disposed into the a receiving socket well on the face, the magnet in the plug attracts the ferromagnetic bar forward against the force of the extension springs bringing the transfer contacts on the transfer bar into electrical continuity with the rear surface of the contacts mounted in the face. Electrical continuity is therefore established from the ring contacts in the plug to the face contacts, the transfer bar contacts, to the terminals and thence to the power circuit. The ring contacts are wired through the plug to a conventional three wire cord and thence made available for general electrical power utilization. When the magnetic plug is removed from the socket well, the springs retract the transfer bar from the face and electrical continuity with the face contacts is interrupted. The face contacts are then not electrified and can be safely be touched without the possibility of electrical shock hazard. 
     While the apparatus and method has or will be described for the sake of grammatical fluidity with functional explanations, it is to be expressly understood that the claims, unless expressly formulated under 35 USC 112, are not to be construed as necessarily limited in any way by the construction of “means” or “steps” limitations, but are to be accorded the full scope of the meaning and equivalents of the definition provided by the claims under the judicial doctrine of equivalents, and in the case where the claims are expressly formulated under 35 USC 112 are to be accorded full statutory equivalents under 35 USC 112. The disclosure can be better visualized by turning now to the following drawings wherein like elements are referenced by like numerals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan diagrammatic view of a wall socket of a first embodiment of the invention. 
         FIG. 2  is a front plan diagrammatic view of a plug matching the socket of  FIG. 1 . 
         FIG. 3  is a side elevational diagrammatic view of the plug of  FIG. 2  and its connecting wire. 
         FIG. 4  is a top cut away diagrammatic view of the socket of  FIG. 1  as seen through the plane of line  4 - 4  of  FIG. 1  when the magnetic plug is removed from the socket or otherwise not present. 
         FIG. 5  is a side cut away diagrammatic view of the socket of  FIG. 1  as seen through line  5 - 5  of  FIG. 1 . 
         FIG. 6  is a side elevational diagrammatic view of the socket of  FIG. 1 . 
         FIG. 7  the a top cut away diagrammatic view of the socket of  FIG. 1  as seen through the plane of line  4 - 4  of  FIG. 1  when the magnetic plug is present and the contacts are activated. 
         FIG. 8  is a close-up top cross sectional diagrammatic view of the face contacts and the activated transfer contacts when engaged with the face contacts. 
         FIG. 9  is a perspective diagrammatic view of an adapter used with the embodiment of  FIGS. 1-8  when employed with a conventional plug. 
         FIG. 10 a    is a front plan view of movable slide carrying the transfer contacts. 
         FIG. 10 b    is a front plan view of a fixed bar carrying the electrical contacts of  FIG. 8  on the front face of the socket. 
     
    
    
     The disclosure and its various embodiments can now be better understood by turning to the following detailed description of the preferred embodiments which are presented as illustrated examples of the embodiments defined in the claims. It is expressly understood that the embodiments as defined by the claims may be broader than the illustrated embodiments described below. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a plan view of a wall socket module  10  of a first embodiment of the invention. In the illustrated embodiment wall socket module  10  includes a wall bar  12  with two sockets  14  which are shallow circular recesses defined into the thickness of wall bar  12 . Sockets  14  are preferentially circular in shape in order to allow for total azimuthal symmetry. In other words, as will be made clear below, it will make difference at what azimuthal angle or orientation that plug  26  is set or disposed into socket  14 . All and any azimuthal orientation will be equivalent and operable. However, if in any application it would to be to an advantage to require socket  14  to have a preferred azimuthal orientation for operation, it is within the scope of the invention that other shapes for socket  14  could be substituted. 
     Wall bar  12  is made of plastic or other nonconducting material and can be attached to the electrical junction box (not shown) by any means or method conventionally employed. Typically, wall bar  12  will be fixed to the junction box using two machine screws disposed through opposing top and bottom mounting holes  22 . Alternatively a center mounting hole may be provided (not shown). Defined into the bottom surface of each recess of socket  14  are a plurality of selectively activatable electrical contacts  16 ,  18  and  20 . As will be described in greater detail in  FIG. 8 , electrical contacts  16 ,  18  and  20  are flush or nearly flush with the bottom surface of the recessed socket  14 . In the illustrated embodiment, three electrical contacts  16 ,  18  and  20  are provided, but the spirit and scope of the invention contembars the use of any number of contacts as may be needed in any specific application. 
       FIG. 2  is an anterior plan view of the face  24  of a plug  26  matching the socket  14  of  FIG. 1 . In the illustrated embodiment, three electrical contacts  28 ,  30 , and  32  are provided on face  24  of plug  26 , but again the spirit and scope of the invention contemplates the use of any number of contacts as may be needed in any specific application. The body of plug  26  is made of plastic or other nonconducting material. Face  24  is circular in cross section and electrical contacts  28 ,  30 , and  32  are defined as ring contacts centered on the circular face  24  and are flush or nearly flush with face  24 . The innermost contact  32  is designated as the hot electrode, the middle contact  30  is the neutral electrode and the outermost contact  28  is the ground electrode in a three-wire electrical plug  26 . It is to be understand that all other orderings of the designation of the contacts  28 ,  30 , and  32  are also contemplated as within the scope of the invention. Therefore, in the illustrated embodiment contact  16  of socket  14  in  FIG. 1  is designated as the hot electrode, contact  18  as the neutral electrode and contact  20  as the ground electrode. A permanent magnet  34  is disposed and fixed in the body of plug  26  in the center of face  24  and is circumscribed by contact  28 . It is within the scope of the invention that the magnet would be differently positioned or configured. For example, an outer ring magnet could be employed or multiple magnets located at different positions of face  24  if desired. 
       FIG. 3  is a side elevational view of the plug  26  of  FIG. 2  and its connecting wire  38  with a stress relief ferrule  36 . Plug  26  is shown as a right prismatic cylinder, but it is within the scope of the invention that only the portion of plug  26  near face  24  need be a circular cylindrical section and the shape of the remainder of the body of plug  26  can be freely chosen. 
       FIG. 4  is a top cut away view of the socket  14  of  FIG. 1  as seen through the plane of line  4 - 4  of  FIG. 1  when the magnetic plug  26  is removed from the socket  14  or otherwise not present or inoperative. Contacts  16 ,  18 , and  20  are disposed in a fixed nonconducting bar  40  comprising the front surface of a socket module  10 . A circumferential circular lip  44  circumscribes bar  40  and provides a mechanical guide into which plug  26  is easily mated or disposed in order to center plug  26  with respect to socket  14 . 
     Spaced behind contact bar  40  is a movable ferromagnetic or magnetic transfer slide  46 . Slide  46  is shown in plan view in  FIG. 10 a    as carrying transfer contacts  16   a ,  18   a  and  20   a  and a magnet  35 . Contact bar  40  is shown in plan view in  FIG. 10 b    as including front contacts  16 ,  18  and  20  along with a hole  37  defined through bar  40  through which aligned magnet  35  fixed to slide  46  may be disposed. Transfer contacts  16   a ,  18   a  and  20   a  are disposed or fixed into transfer slide  46 , but electrically insulated therefrom so that they are not shorted out with each other. Transfer contacts  16   a ,  18   a  and  20   a  are aligned with fixed contacts  16 ,  18  and  20  respectively in fixed bar  40 , such that when transfer slide  46  is moved forward as described below, transfer contacts  16   a ,  18   a  and  20   a  achieve electrical continuity with contacts  16 ,  18  and  20  respectively. Transfer slide  46  is mounted on a plurality of extension springs  48  extending between contact bar  40  and transfer slide  46  in a plurality of end positions of bars  40  and  46 . Each of the transfer contacts  16   a ,  18   a  and  20   a  is electrically coupled by means of a flexible wire or resilient conducting lead  50  to corresponding fixed terminals  16   b ,  18   b  and  20   b  respectively. Terminals  16   b ,  18   b  and  20   b  are thus the ground, neutral and hot terminals respectively of socket module  10 , are fixed to mounting bar  47  and extend to the rear of socket module  10  to allow for conventional coupling to the house or power electrical wiring.  FIG. 6  is a side elevational view of the socket module  10  of  FIG. 1  showing two rows of terminals in module  10  with only terminal  20   b  seen. 
     The operation of socket module  10  may now be understood. Socket module  10  is normally in an inactivated configuration as shown in  FIG. 4 . However, when magnetic plug  26  is disposed into socket  14 , the magnet  34  in plug  26  will attract ferromagnetic or magnetic transfer slide  46  toward bar  40  against the tensile force of extension springs  48  by reason of either the ferromagnetic quality of slide  46  or the mutual attraction of magnets  34  and  35  or both. Contacts  16   a ,  18   a  and  20   a  will come into electrical contact with contacts  16 ,  18  and  20  respectively and electrical continuity will be established from contacts  16 ,  18  and  20  through contacts  16   a ,  18   a  and  20   a  through wires  50  to terminals  16   b ,  18   b  and  20   b  respectively. The spring constants of extension springs  48 , the degree of their extension, and the spacing of bars  40  and  46  are selected so that force of magnet  34  is always sufficient to securely move slide  46  toward bar  40  to establish electrical continuity between contacts  16 ,  18  and  20  and contacts  16   a ,  18   a  and  20   a  respectively. Socket module  10  is now in the activated configuration shown in to the top cut-away view of  FIG. 7  or in the cut away view of  FIG. 5  as seen through line  5 - 5  of  FIG. 1 .  FIG. 7  the a top cut away view of the socket module  10  of  FIG. 1  as seen through the plane of line  4 - 4  of  FIG. 1  when the magnetic plug  26  is present and the contacts  16 ,  18  and  20  are activated. In the activated configuration electrical power is or can be supplied to plug  26 . 
     In the illustrated embodiment, transfer slide  46  is spaced from the walls of socket module  10  and free floating on springs  48  so that there is no mechanical friction resisting the movement of slide  46  either toward or away from bar  40 . When magnetic plug  26  is removed from socket  14 , the magnetic force holding slide  46  forward against bar  40  is lessened or removed and springs  48  retract slide  46  to place socket module  10  into the inactivated configuration. However, if more mechanical stability is required, it is within the scope of the invention that keys and keyways can be defined (not shown) in the interior walls of socket module  10  and/or slide  46  to guide slide  46  in its forward and backward movements within socket module  10 . 
     It is also within the scope of the invention that if less magnetic force is able to satisfactorily operate socket module  10  that magnet  35  may be omitted. Although it is not the preferred embodiment, plug  26  may be ferromagnetic instead of carrying magnet  34  and attraction between plug  26  and slide  46  will be provided by the interaction of magnet  35  in slide  46  with the ferromagnetic quality of plug  26 . 
       FIG. 8  is a close-up top cross sectional fragmentary view of the face contacts  16 ,  18 , and  20  and the activated transfer contacts  16   a ,  18   a , and  20   a  when engaged with the face contacts  16 ,  18 , and  20  respectively. Contacts  16 ,  18 , and  20  are shown in exaggerated form as dumbbell shaped with enlarged heads or contact surfaces extending from the front and rear surface of bar  40 . In the illustrated embodiment contacts  16 ,  18  and  20  are loosely retained by their dumbbell shape in bar  40  to allow a limited degree of movement or angular orientability of contacts  16 ,  18  and  20  in bar  40 . This allows contacts  16 ,  18  and  20  to settle in an optimal or conforming position or orientation between the ring contacts  28 ,  30  and  32  of plug  26  and transfer contacts  16   a ,  18   a  and  20   a  of socket module  10  in any given connection or mating notwithstanding small misalignments in any of the components. 
       FIG. 9  is a perspective view of an adapter  26   a  used with the embodiment of  FIGS. 1-8  when employed with a three-prong conventional plug  54 . Magnetic plug  26  and socket module  10  comprises an integral or compatible electrical mating system. However, as with the introduction of any new technology means must be provided to allow for compatibility or use with pre-existing conventional systems. Adapter  26   a  has the identical material components of plug  26  of  FIGS. 2 and 3 , namely ring contacts  28 ,  30 , and  32  and magnet  34  insulatively separated from each other provided on one end of adapter  26   a , but these contacts  28 ,  30 , and  32  are internally coupled or wired (not shown) to a conventional three-pronged socket  52  provided on the opposing end of adapter  26   a . As shown in the lower portion of  FIG. 9 , adapter  26   a  is connectable to a conventional three-pronged plug  54  and cord  56 . Adapter  26   a  can then be disposed into socket module  10  to allow operation according to the illustrated embodiment of the invention. 
     In the foregoing a circular shape has been shown for contacts  16 ,  18 ,  20 ,  16   a ,  18   a , and  20   a , however it is within the scope of the invention that contacts  16 ,  18 ,  20 ,  16   a ,  18   a , and  20   a  may assume any cross sectional shape or size and need not be equal to each other. For example contacts  16 ,  18  and  20  may be circular in cross-sectional shape with a first diameter and transfer contacts  16   a ,  18   a  and  20   a  may have a circular cross-sectional shape with a second different or large diameter, or may assume a different cross-sectional shape if desired. 
     Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the embodiments. Therefore, it must be understood that the illustrated embodiment has been set forth only for the purposes of example and that it should not be taken as limiting the embodiments as defined by the following embodiments and its various embodiments. 
     Therefore, it must be understood that the illustrated embodiment has been set forth only for the purposes of example and that it should not be taken as limiting the embodiments as defined by the following claims. For example, notwithstanding the fact that the elements of a claim are set forth below in a certain combination, it must be expressly understood that the embodiments includes other combinations of fewer, more or different elements, which are disclosed in above even when not initially claimed in such combinations. A teaching that two elements are combined in a claimed combination is further to be understood as also allowing for a claimed combination in which the two elements are not combined with each other, but may be used alone or combined in other combinations. The excision of any disclosed element of the embodiments is explicitly contembard as within the scope of the embodiments. 
     The words used in this specification to describe the various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself. 
     The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contembard that an equivalent substitution of two or more elements may be made for any one of the elements in the claims below or that a single element may be substituted for two or more elements in a claim. Although elements may be described above as acting in certain combinations and even initially claimed as such, it is to be expressly understood that one or more elements from a claimed combination can in some cases be excised from the combination and that the claimed combination may be directed to a subcombination or variation of a subcombination. 
     Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contembard as being equivalently within the scope of the claims. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. 
     The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptionally equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the embodiments.