Abstract:
A ganged electrical receptacle unit with locking feature includes a plurality of receptacles and a lock housing. The electrical receptacles are ganged together. The lock housing extends from a front of the receptacles and includes a pair of opposed side supports, a pair of torsion bars, each extending between the opposed side supports, a lock tab extending from each torsion bar toward the receptacle, and a release tab extending from each torsion bar away from the receptacle. A plug may be inserted into the lock housing causing temporary deflection of the lock tabs until the plug is seated in, and electrically connected with, the receptacle, at which point the lock tabs return to their undeflected positions and retain the plug in the receptacle. The release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the lock housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a U.S. non-provisional patent application of, and claims priority under 35 U.S.C. §119(e) to, U.S. provisional patent application Ser. No. 62/008,124, filed Jun. 5, 2014 and entitled, “ELECTRICAL RECEPTACLE WITH LOCKING FEATURE,” which &#39;124 application is incorporated by reference herein in its entirety. 
     
    
     COPYRIGHT STATEMENT 
       [0002]    All of the material in this patent document is subject to copyright protection under the copyright laws of the United States and other countries. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in official governmental records but, otherwise, all other copyright rights whatsoever are reserved. 
       BACKGROUND OF THE PRESENT INVENTION 
       [0003]    1. Field of the Present Invention 
         [0004]    The present invention relates generally to power cords and their connectors, and, in particular, to plug retention devices for electrical receptacles. 
         [0005]    2. Background 
         [0006]    Power cords are ubiquitous in the developed world, providing power from a conventional distribution system to electrically-powered devices of a very wide variety of types. Each power cord usually includes a cable with a plug or other electrical fitting at each end. For residential devices, most power cords utilize a plug having a standard size and arrangement of electrical connectors, with the particular standard being specific to a particular country or set of countries. Power cords for devices having electrical requirements that are different from that standard frequently utilize different sizes and/or arrangements to ensure that the wrong plug is not connected thereto. 
         [0007]    In the computer industry, specialized plug/receptacle pairs are likewise used for various electrical needs. The plug/receptacle pairs are typically selected from conventional receptacle designs such as those set forward by IEC 60320. According to the standard, the specifications of corresponding female and male pairs of electrical connectors (such as C13 and C14 types) are defined such that the physical attributes of those connectors are standardized. By way of example,  FIG. 1  is a front isometric view of a conventional female electrical receptacle. The illustrated receptacle is in the form of a panel-mount C13-type receptacle, but it will be appreciated that various other receptacle types with different electrical connection configurations also exist. The receptacle includes a female fitting surrounded by a socket. Female electrical contacts are contained within the female fitting. A plate may be provided on the front of, and typically integral with, the socket. The receptacle may be mounted in various fixtures using screws, solder joints, or in other known ways; the receptacle (and especially the socket) may include additional features to facilitate such mounting. The female electrical receptacle is adapted to receive a corresponding male electrical receptacle (not shown in  FIG. 1 ). Such a male receptacle would typically include a male fitting from which male electrical contacts extend as well as a socket surrounding the male electrical contacts. 
         [0008]    A common problem within the computer industry and without is the accidental dislocation of a particular plug (connector) from a receptacle. Because each plug commonly has a cord extending therefrom, it is easy to generate enough force, accidentally, to loosen the plug in the receptacle or even to pull it out entirely. Contributing to the problem is the fact that many connectors are designed to be removed easily by hand, which means that the force necessary to loosen or remove the plug is often not particularly great. The problem can be particularly vexing around power distribution units (PDUs). 
         [0009]    As a result, many devices and techniques have been used to hold plugs in place. These include plugs that include threaded fittings (e.g., screws) that may be coupled to corresponding fittings on the receptacle, a retention element installed on the cord that can be attached to a stud or other element of the receptacle or PDU, bars or brackets fastened to the receptacle or PDU once the plug or plugs are in place, and the like. All of these have problems, from the need for special connector designs to their difficulty of use, particularly with regard to their ease of installation and removal. Thus, a need exists for a solution that does not require changes to the plug but which allows for easy installation and removal of the plug in and from a receptacle, while reliably holding the plug in place while installed. 
       SUMMARY OF THE PRESENT INVENTION 
       [0010]    Broadly defined, the present invention according to one aspect is an electrical receptacle with locking feature as shown and described. 
         [0011]    Broadly defined, the present invention according to another aspect is an electrical receptacle with locking feature, including: a receptacle adapted to be electrically connected to a source of electricity and having a front face; and a lock housing extending from the front face of the receptacle. 
         [0012]    Broadly defined, the present invention according to another aspect is an electrical receptacle with locking feature, including: a receptacle adapted to be electrically connected to a source of electricity and having a front face; and a lock housing extending from the front face of the receptacle, wherein the lock housing includes a pair of opposed side supports, a pair of torsion bars, each extending between and supported by the opposed side supports, a respective lock tab extending from each torsion bar toward the receptacle, and a respective release tab extending from each torsion bar away from the receptacle; wherein a plug may be inserted into the lock housing such that the plug causes the temporary deflection of the lock tabs until the plug is seated in, and electrically connected with, the receptacle, at which point the lock tabs return to their undeflected positions and retain the plug in the receptacle in its electrically connected state; and wherein the release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the lock housing. 
         [0013]    Broadly defined, the present invention according to another aspect is a ganged electrical receptacle unit with locking feature as shown and described. 
         [0014]    Broadly defined, the present invention according to another aspect is a ganged electrical receptacle unit with locking feature, including: a plurality of receptacles ganged together and having a front face, the ganged receptacles being adapted to be electrically connected to a source of electricity; and a lock housing extending from the front face of at least one of the ganged receptacles. 
         [0015]    In a feature of this aspect, a respective lock housing extends from the front face of each of the ganged receptacles. In a further feature, each lock housing includes a pair of opposed side supports, a pair of torsion bars, each extending between and supported by the opposed side supports, a respective lock tab extending from each torsion bar toward the respective ganged receptacle, and a respective release tab extending from each torsion bar away from the respective ganged receptacle; a plug may be inserted into each respective lock housing such that the plug causes the temporary deflection of the lock tabs until the plug is seated in, and electrically connected with, the respective ganged receptacle, at which point the lock tabs return to their undeflected positions and retain the plug in the respective ganged receptacle in its electrically connected state; and the release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the respective lock housing. 
         [0016]    In a further feature, each pair of adjacent receptacles shares a side support. 
         [0017]    In another further feature, the lock housings are ganged together. In still further features, the lock housings are integral with one another, or the lock housings are produced separately but are attached to each other. 
         [0018]    In another further feature, the lock housings are integral with the ganged receptacles. 
         [0019]    In another further feature, the lock housings are produced separately from the ganged receptacles but are attached to the ganged receptacles. 
         [0020]    In another further feature, each lock housing includes a front plate from which the side supports extend. 
         [0021]    In another further feature, the plug and receptacle are of a C13/C14-type. 
         [0022]    Broadly defined, the present invention according to another aspect is a ganged electrical receptacle unit with locking feature, including: a plurality of receptacles ganged together and having a front face, the ganged receptacles being adapted to be electrically connected to a source of electricity; and a lock housing extending from the front face of at least one of the ganged receptacles, wherein the lock housing includes a pair of opposed side supports, a pair of torsion bars, each extending between and supported by the opposed side supports, a respective lock tab extending from each torsion bar toward the at least one ganged receptacle, and a respective release tab extending from each torsion bar away from the at least one ganged receptacle; a plug may be inserted into the lock housing such that the plug causes the temporary deflection of the lock tabs until the plug is seated in, and electrically connected with, the at least one ganged receptacle, at which point the lock tabs return to their undeflected positions and retain the plug in the at least one ganged receptacle in its electrically connected state; and the release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the lock housing. 
         [0023]    Broadly defined, the present invention according to another aspect is an electrical receptacle unit with locking feature, including: a receptacle adapted to be electrically connected to a source of electricity and having a front; and a lock housing extending from the front of the receptacle and adapted to surround a plug and temporarily lock the plug in place in coupling disposition with regard to the receptacle. 
         [0024]    In a feature of this aspect, the receptacle includes an electrical fitting, having electrical contacts contained therein and/or extending therefrom; the receptacle includes a socket surrounding the electrical fitting; and the lock housing extends from a plate disposed on the front of the socket. In a further feature, the electrical fitting is a first electrical fitting; the lock housing includes a pair of opposed side supports, a pair of torsion bars, each torsion bar extending between and supported by the opposed side supports, and a respective lock tab extending from each torsion bar toward the electrical fitting; and a plug, including a second electrical fitting that mates to the first electrical fitting, may be inserted into the lock housing such that the plug causes the temporary deflection of the lock tabs until the plug is coupled to, and electrically connected with, the receptacle, at which point the lock tabs return to their undeflected positions and retain the plug coupled to the receptacle in its electrically connected state. In still further features, the lock housing includes a respective release tab extending from each torsion bar away from the electrical fitting; and the release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the lock housing; the opposed side supports are upper and lower side supports; the opposed side supports are left and right side supports; the receptacle is a panel-mount receptacle; the socket of the receptacle includes walls, at least one of which walls includes a locking tab that retains the receptacle in a fixture; the electrical fitting is a female electrical fitting having female electrical contacts contained therein; and/or the plug and receptacle are of a C13/C14-type. 
         [0025]    In another feature of this aspect, the receptacle includes an electrical fitting, having electrical contacts contained therein and/or extending therefrom; and the lock housing extends from a plate disposed on the front of the electrical fitting. 
         [0026]    Broadly defined, the present invention according to another aspect is a ganged electrical receptacle unit with locking feature, including: a plurality of receptacles ganged together and each having a front, the ganged receptacles being adapted to be electrically connected to a source of electricity; and a lock housing extending from the front of at least one of the ganged receptacles and adapted to surround a plug and temporarily lock the plug in place in coupling disposition with regard to the at least one ganged receptacle. 
         [0027]    In a feature of this aspect, a respective lock housing extends from the front of each of the ganged receptacles. In a further feature, for each respective receptacle and lock housing, the receptacle includes an electrical fitting, having electrical contacts contained therein and/or extending therefrom, the receptacle includes a respective socket surrounding the electrical fitting, and the lock housing extends from a plate disposed on the front of the socket. In a still further feature, for each respective receptacle and lock housing the electrical fitting is a respective first electrical fitting; the lock housing includes a pair of opposed side supports, a pair of torsion bars, each torsion bar extending between and supported by the opposed side supports, a respective lock tab extending from each torsion bar toward the electrical fitting, and the lock housing includes a respective release tab extending from each torsion bar away from the electrical fitting; a plug, including a second electrical fitting that mates to the first electrical fitting, may be inserted into the lock housing such that the plug causes the temporary deflection of the lock tabs until the plug is coupled to, and electrically connected with, the receptacle, at which point the lock tabs return to their undeflected positions and retain the plug coupled to the receptacle in its electrically connected state; and the release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the lock housing. In still further features, each pair of adjacent receptacles shares a side support; the lock housings are ganged together; the lock housings are integral with one another; the lock housings are produced separately but are attached to each other; the lock housings are integral with the ganged receptacles; the lock housings are produced separately from the ganged receptacles but are attached to the ganged receptacles; and each lock housing includes a front plate from which the side supports extend. 
         [0028]    Broadly defined, the present invention according to another aspect is a ganged electrical receptacle unit with locking feature, including: a plurality of receptacles ganged together, the ganged receptacles being adapted to be electrically connected to a source of electricity, wherein each receptacle includes a first electrical fitting and a respective socket, having a front, that surrounds the first electrical fitting; and a lock housing extending from the front of the socket of at least one of the ganged receptacles, wherein the lock housing includes a pair of opposed side supports, a pair of torsion bars, each torsion bar extending between and supported by the opposed side supports, a respective lock tab extending from each torsion bar toward the at least one ganged receptacle, and a respective release tab extending from each torsion bar away from the at least one ganged receptacle; wherein a plug, including a second electrical fitting that mates to the first electrical fitting, may be inserted into the lock housing such that the plug causes the temporary deflection of the lock tabs until the plug is seated in, and electrically connected with, the at least one ganged receptacle, at which point the lock tabs return to their undeflected positions and retain the plug coupled to the at least one ganged receptacle in its electrically connected state; and wherein the release tabs may be depressed to release the lock tabs from the plug, thereby permitting the withdrawal of the plug from the lock housing 
         [0029]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Further features, embodiments, and advantages of the present invention will become apparent from the following detailed description with reference to the drawings, wherein: 
           [0031]      FIG. 1  is a front isometric view of a conventional female electrical receptacle; 
           [0032]      FIG. 2  is a front isometric view of an electrical receptacle unit with locking feature in accordance with a preferred embodiment of the present invention; 
           [0033]      FIG. 3  is a front isometric view of the electrical receptacle unit of  FIG. 2  shown mounted in a fixture, wherein the fixture is illustrated schematically; 
           [0034]      FIG. 4  is a front isometric view of the electrical receptacle unit of  FIG. 2 , shown with a power cord connected thereto; 
           [0035]      FIG. 5  is a front isometric view of the electrical receptacle unit of  FIG. 4 , shown with the power cord removed therefrom; 
           [0036]      FIG. 6A  is a top cross-sectional view of the electrical receptacle unit and plug of  FIG. 5 , taken along line  6 A- 6 A; 
           [0037]      FIG. 6B  is a top cross-sectional view of the electrical receptacle unit and plug of  FIG. 6A , shown with the plug partially inserted into the receptacle; 
           [0038]      FIG. 6C  is a top cross-sectional view of the electrical receptacle unit and plug of  FIG. 6A , shown with the plug more fully inserted into the receptacle; 
           [0039]      FIG. 6D  is a top cross-sectional view of the electrical receptacle unit and plug of  FIG. 6A , taken along line  6 D- 6 D, showing the plug fully inserted into the receptacle; 
           [0040]      FIG. 6E  is a top cross-sectional view of the electrical receptacle unit and plug of  FIG. 6A , illustrating the forces applied on the lock tabs when the plug is pulled from the receptacle; 
           [0041]      FIG. 6F  is a top cross-sectional view of the electrical receptacle unit and plug of  FIG. 6A , shown with the plug being released from the receptacle; 
           [0042]      FIG. 7  is a front isometric view of a ganged electrical receptacle unit with locking feature in accordance with another preferred embodiment of the present invention; 
           [0043]      FIG. 8  is a rear view of the ganged electrical receptacle unit of  FIG. 7 ; and 
           [0044]      FIG. 9  is a front isometric view of the ganged electrical receptacle unit of  FIG. 7 , shown with a plug of a power cord connected thereto. 
       
    
    
     DETAILED DESCRIPTION 
       [0045]    As a preliminary matter, it will readily be understood by one having ordinary skill in the relevant art (“Ordinary Artisan”) that the present invention has broad utility and application. Furthermore, any embodiment discussed and identified as being “preferred” is considered to be part of a best mode contemplated for carrying out the present invention. Other embodiments also may be discussed for additional illustrative purposes in providing a full and enabling disclosure of the present invention. As should be understood, any embodiment may incorporate only one or a plurality of the above-disclosed aspects of the invention and may further incorporate only one or a plurality of the above-disclosed features. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present invention. 
         [0046]    Accordingly, while the present invention is described herein in detail in relation to one or more embodiments, it is to be understood that this disclosure is illustrative and exemplary of the present invention, and is made merely for the purposes of providing a full and enabling disclosure of the present invention. The detailed disclosure herein of one or more embodiments is not intended, nor is to be construed, to limit the scope of patent protection afforded the present invention, which scope is to be defined by the claims and the equivalents thereof. It is not intended that the scope of patent protection afforded the present invention be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself. 
         [0047]    Thus, for example, any sequence(s) and/or temporal order of steps of various processes or methods that are described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal order, the steps of any such processes or methods are not limited to being carried out in any particular sequence or order, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and orders while still falling within the scope of the present invention. Accordingly, it is intended that the scope of patent protection afforded the present invention is to be defined by the appended claims rather than the description set forth herein. 
         [0048]    Additionally, it is important to note that each term used herein refers to that which the Ordinary Artisan would understand such term to mean based on the contextual use of such term herein. To the extent that the meaning of a term used herein—as understood by the Ordinary Artisan based on the contextual use of such term—differs in any way from any particular dictionary definition of such term, it is intended that the meaning of the term as understood by the Ordinary Artisan should prevail. 
         [0049]    Regarding applicability of 35 U.S.C. §112, ¶6, no claim element is intended to be read in accordance with this statutory provision unless the explicit phrase “means for” or “step for” is actually used in such claim element, whereupon this statutory provision is intended to apply in the interpretation of such claim element. 
         [0050]    Furthermore, it is important to note that, as used herein, “a” and “an” each generally denotes “at least one,” but does not exclude a plurality unless the contextual use dictates otherwise. Thus, reference to “a picnic basket having an apple” describes “a picnic basket having at least one apple” as well as “a picnic basket having apples.” In contrast, reference to “a picnic basket having a single apple” describes “a picnic basket having only one apple.” 
         [0051]    When used herein to join a list of items, “or” denotes “at least one of the items,” but does not exclude a plurality of items of the list. Thus, reference to “a picnic basket having cheese or crackers” describes “a picnic basket having cheese without crackers,” “a picnic basket having crackers without cheese,” and “a picnic basket having both cheese and crackers.” Finally, when used herein to join a list of items, “and” denotes “all of the items of the list.” Thus, reference to “a picnic basket having cheese and crackers” describes “a picnic basket having cheese, wherein the picnic basket further has crackers,” as well as describes “a picnic basket having crackers, wherein the picnic basket further has cheese.” 
         [0052]    Referring now to the drawings, in which like numerals represent like components throughout the several views, one or more preferred embodiments of the present invention are next described. The following description of one or more preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  FIG. 2  is a front isometric view of an electrical receptacle unit  10  with locking feature in accordance with a preferred embodiment of the present invention. As shown therein, the electrical receptacle unit  10  includes a female electrical fitting  12 , a surrounding socket  13 , and a lock housing  20  extending from the front of the surrounding socket  13 . The illustrated female fitting  12  is in the form of a panel-mount C13-type receptacle, but it will be appreciated that various other receptacle types with different electrical connection configurations also exist. Female electrical contacts similar to those of the fitting in  FIG. 1  are contained within the female fitting  12 . A plate  14  is provided on the front of the socket  13 . In at least some embodiments, the plate  14  is integral with the socket  13 , but in other embodiments the plate  14  may be attached during or after manufacturing. Further, in some alternative embodiments, the plate is omitted entirely. In other embodiments, the plate is integral with, or attached to, the electrical fitting. 
         [0053]      FIG. 3  is a front isometric view of the electrical receptacle unit  10  of  FIG. 2  shown mounted in a fixture  100 , wherein the fixture  100  is illustrated schematically. The receptacle unit  10  may be mounted in various fixtures using screws, solder joints, or in other known ways; the receptacle (and especially the socket) may include additional features to facilitate such mounting. In accordance with one or more preferred approaches to mounting the receptacle unit  10 , the walls of the socket  13  may include locking tabs  15  (as can be seen in FIG.  4 ) that are naturally depressed as the socket  13  is maneuvered into position in the fixture  100 , but are biased to spring outward when the socket  13  is fully inserted into such fixture  100 , thereby holding the receptacle unit  10  in place in the fixture  100 . 
         [0054]    In at least some embodiments, the lock housing  20  is integral with the socket  13  of the receptacle unit and is co-manufactured with the socket  13 , while in others the lock housing  20  is manufactured separately from the socket  13  and is fastened thereto. The lock housing  20  includes opposed side supports  22  connected by a pair of torsion bars  24 . In the illustrated embodiment, the side supports  22  extend forwardly from the plate  14 , but it will be appreciated that side supports or similar structures could alternatively or additionally extend from other portions of the socket  13  or other structure. It will also be appreciated that although the side supports  22  are located on the upper and lower sides of the lock housing  20 , side supports could alternatively be located on the left and right sides of a lock housing. Each torsion bar  24  supports a lock tab  26  and a release tab  28  extending in generally opposite directions therefrom. The side supports  22  and release tabs  28  collectively frame a lock housing opening  30 . 
         [0055]    The female electrical fitting  12  is adapted to receive a corresponding male electrical fitting. In this regard,  FIG. 4  is a front isometric view of the electrical receptacle unit  10  of  FIG. 2 , shown with a power cord connected thereto, and  FIG. 5  is a front isometric view of the electrical receptacle unit  10  of  FIG. 4 , shown with the power cord removed therefrom. As shown in cross-section in  FIGS. 6A-6F , the power cord includes a plug  40  attached to the end of an electrical cable  44 . The plug  40  includes a male fitting  42 , from which male electrical contacts  41 , extend as well as a socket  43  surrounding the male electrical contacts  41 . As shown in  FIGS. 4 and 5 , the plug  40  may be guided through the lock housing opening  30  and then inserted into the receptacle unit  10  such that a conventional electrical connection is established and maintained. In at least some embodiments, the plug  40  is of conventional construction, as is the electrical cable  44  to which it is attached. When fully seated in the lock housing opening  30  and socket  13 , as shown in  FIG. 4 , the plug  40  is retained by the lock housing  20  such that it will not become “unplugged” or otherwise disconnected accidentally. 
         [0056]      FIGS. 6A-6F  are a series of top cross-sectional views of the electrical receptacle unit  10  and plug  40  of  FIGS. 4 and 5 . In  FIGS. 6A-6F , a circular arrow is sometimes used to illustrated rotational movement of the lock tabs  26  around the axis defined by the torsion bars  24 , which are designed to be flexible and resilient enough to facilitate such temporary rotation. As shown in  FIG. 6A , which is a top cross-sectional view of the electrical receptacle unit  10  and plug  40  of  FIG. 5 , taken along line  6 A- 6 A, the plug  40  is aligned with the lock housing opening  30  and socket  13 . As the plug  40  is guided into the lock housing opening  30 , as shown in  FIG. 6B , leading edges  32  of the sides of the socket  43  make contact with the lock tabs  26  of the lock housing  20 . When sufficient force  52  is applied to the plug  40 , the leading edges  32  cause the lock tabs  26  to begin deflecting outward as represented by the arrows  54 . In particular, the lock tabs  26  begin rotating around the axis defined by the torsion bars  24 , which as described previously are designed to be flexible and resilient enough to facilitate such temporary rotation. Because the release tabs  28  are likewise supported by the torsion bars  24 , the release tabs  28  rotate slightly as well. As shown in  FIG. 6C , when the lock tabs  26  have rotated sufficiently to accommodate the width of the plug  40 , the plug  40  may be guided into mating relationship with the female electrical fitting  12  itself. 
         [0057]    Once the plug  40  is fully seated in the receptacle unit  10 , trailing edges  34  of the sides of the plug  40  have passed completely by the lock tabs  26 , at which point the lock tabs  26  spring back to their original positions. This arrangement is shown in  FIG. 6D , which is a top cross-sectional view of the electrical receptacle unit  10  and plug  40  of  FIG. 4 , taken along line  6 D- 6 D. In their normal, unbiased state, the ends of the locking tabs  26  are disposed against or adjacent the trailing edges  34  of the plug  40 , thereby blocking the plug  40  from being removed. Furthermore, because the force  56  applied on the locking tabs  26  when the plug  40  is pulled outward tends to cause the locking tabs  26  to rotate around the axis defined by the torsion bars  24 , such a force  56  will tend to cause the locking tabs  26  to be deflected inward, thereby providing even greater resistance to the pulling force  56  being applied. In other words, the locking feature actually increases its holding strength when the power cord is pulled because the locking tabs  26  are forced inward in that circumstance. This is illustrated in  FIG. 6E , which is a top cross-sectional view of the electrical receptacle unit  10  and plug  40  of  FIG. 6A , illustrating the forces  58  applied on the lock tabs  26  when a pulling force  56  is applied to the plug  40 . 
         [0058]    Although the lock tabs  26  prevent the plug  40  from being pulled from the receptacle unit  10  accidentally, the plug  40  nonetheless may be released easily from the lock housing  20  by manipulating the release tabs  28 . In particular, the release tabs  28  may be gripped by hand and squeezed toward the sides of the plug  40 , causing the lock tabs  26  to rotate around the torsion bar axis, away from the sides of the plug  12 . This may be accomplished, for example, via a user&#39;s thumb and index fingers applying a force as represented by the arrows  60 . In this regard,  FIG. 6F  is a top cross-sectional view of the electrical receptacle unit  10  and plug  40  of  FIG. 6A , shown with the plug  40  being released from the receptacle unit  10 . Once the lock tabs  26  have been rotated far enough that they no longer block the trailing edges  34  of the sides of the plug  40 , the plug  40  may be easily removed from the female electrical fitting  12  and from the lock housing  20 . 
         [0059]      FIGS. 7 and 8  are a front isometric view and a rear view, respectively, of a ganged electrical receptacle unit  110  with locking feature in accordance with another preferred embodiment of the present invention. As shown therein, the electrical receptacle unit  110  includes a ganged series of female electrical fittings  12 , surrounding sockets  113 , and lock housings  120  extending from the fronts of the sockets  113 . In the illustrated embodiment, the female fittings, which have female electrical contacts contained therein, are similar to those of  FIG. 2 , but it will be again be appreciated that various other receptacle types with different electrical connection configurations also exist. A single continuous plate  114  is provided on the front of the sockets  113 . In at least some embodiments, the plate  114  is integral with the socket  113 , but in other embodiments the plate  114  may be attached during or after manufacturing. Further, in some alternative embodiments, the plate is omitted entirely. In other embodiments, the plate is integral with, or attached to, one or more of the electrical fittings. 
         [0060]    The receptacle unit  110  may be mounted in various fixtures using screws, solder joints, or in other known ways; the receptacle (and especially the socket) may include additional features to facilitate such mounting. In accordance with one or more preferred approaches to mounting the receptacle unit  110 , the walls of one or more of the sockets  113  may include locking tabs  15  that are naturally depressed as the sockets  113  are maneuvered into position in a fixture (not shown), but are biased to spring outward when the sockets  113  are fully inserted into such fixture, thereby holding the receptacle unit  110  in place in the fixture. 
         [0061]    In at least some embodiments, the lock housings  120  are integral with the plate  114  and/or sockets  113  of the receptacle unit and is co-manufactured with the plate  114  and/or sockets  113 , while in others the lock housings  120  are manufactured separately from the plate  114  and/or sockets  113  and are fastened thereto. Furthermore, in at least some embodiments, the lock housings  120  are integral with one another and are co-manufactured with one another, while in others the lock housings  120  are manufactured separately from one another and are fastened together. Still further, in at least some embodiments, the sockets  113  are integral with one another and are co-manufactured with one another, while in others the sockets  113  are manufactured separately from one another and are fastened together. In the illustrated embodiment, the sockets  113  are ganged together via an integral backbone  116 . 
         [0062]    An upper or lower side support  22  is disposed at each end of the ganged series of lock housings  120 , and intermediate side supports  122  are interspersed between the sockets  113 . In the illustrated embodiment, the upper and lower end side supports  22  and the intermediate side supports  122  all extend forwardly from the plate  114 , but it will be appreciated that side supports or similar structures could alternatively or additionally extend from other portions of the socket  113  or other structure(s). Each pair of adjacent end (upper and lower) and intermediate side supports  22 , 122  are connected by a pair of torsion bars  24 . Each torsion bar  24  supports a lock tab  26  and a release tab  28  extending in generally opposite directions therefrom. The side supports  22 , 122  and release tabs  28  of each lock housing  120  collectively frame a lock housing opening  130 . 
         [0063]    Each female electrical fitting  12  is adapted to receive a corresponding male electrical fitting. In this regard,  FIG. 9  is a front isometric view of the ganged electrical receptacle unit of  FIG. 7 , shown with a plug  40  of a power cord connected thereto. As described previously, the power cord includes a plug  40  attached to the end of an electrical cable  44 . The plug  40  includes a male fitting  42 , from which male electrical contacts  41 , extend as well as a socket  43  surrounding the male electrical contacts  41 . As shown in  FIG. 9 , the plug  40  may be inserted through one of the lock housing openings  130  and into the receptacle unit  110  such that a conventional electrical connection is established and maintained. In at least some embodiments, the plug  40  is of conventional construction, as is the electrical cable  44  to which it is attached. When fully seated in the lock housing opening  130  and socket  113 , as shown in  FIG. 9 , the plug  40  is retained by the lock housing  120  such that it will not become “unplugged” or otherwise disconnected accidentally. The operation of the lock housing  120  is similar to that of the lock housing  20  of  FIGS. 6A-6F . 
         [0064]    It will be appreciated that although the receptacle units  10 , 110  described and illustrated herein utilize female electrical fittings  12  and female electrical contacts that are adapted to receive male electrical fittings  42  and male electrical contacts  41 , receptacle units (not shown) could additionally or alternatively be provided with male electrical fittings and/or male electrical contacts that are adapted to be received by power cords having plugs with female electrical fittings and/or female electrical contacts. 
         [0065]    Based on the foregoing information, it will be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those specifically described herein, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing descriptions thereof, without departing from the substance or scope of the present invention. 
         [0066]    Accordingly, while the present invention has been described herein in detail in relation to one or more preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purpose of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended to be construed to limit the present invention or otherwise exclude any such other embodiments, adaptations, variations, modifications or equivalent arrangements; the present invention being limited only by the claims appended hereto and the equivalents thereof.