Patent Publication Number: US-10784627-B1

Title: Metal self-locking extension cord

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to extension cords and, more particularly, to a self-locking extension cord having an adjustable, metal, and impermeable construction for extending electrical power to an associated electrical power cord or tool having an electrical cord. 
     Extension cords have been used almost since the beginning of delivering electrical current through wires. Such cords allow the delivery of electricity over long distances and are critical to industries such as construction jobs, connection of tools outside a business or residence, and oftentimes in very rugged environments. A major problem with connecting multiple extension cords together, of course, is that if any single connection of male-female receptacles are pulled apart, electrical power is interrupted until the location of separation is located and plugged back in. Another problem with traditional extension cords is that rugged environments may result in damage, holes, or rips in the cord that may expose the electrical wires inside and cause danger of electrocution, fire, or inconsistent operation. 
     Various devices have been proposed in the prior art for interlocking male-female receptacles together in an effort to make extension cords more reliable. Although presumably effective for their intended purposes, there is still a need for a more comprehensive self-locking extension cord implementing a metal, durable, and yet partially flexible electrical cable that also includes a male plug receiving housing for joining multiple extension cords or tool power cables together. 
     Therefore, it would be desirable to have a self-locking extension cord that satisfies the objectives of the present invention and improves the disadvantages of traditional extension cords. 
     SUMMARY OF THE INVENTION 
     A self-locking extension cord according to the present invention for use with an auxiliary male electrical plug associated with an auxiliary electrical cord includes a cord member having opposed first and second ends, the cord member having an elongate configuration and is constructed of an adjustable metal material that defines an interior channel containing a plurality of conductive wires. The extension cord includes a male electrical receptacle fixedly attached to the first end of the cord member and is electrically connected to the plurality of wires in the interior channel of the cord member. The extension cord also includes a male plug receiving member selectively and releasably coupled to the first end of the cord member, the male plug receiving member, including a first receiving portion and a second receiving portion pivotally coupled to the first receiving portion and movable between a closed configuration in which the first and second receiving portions, together, define an interior area and an open configuration operable to receive into the interior area one of the male electrical receptacle or the auxiliary male electrical receptacle associated with the auxiliary extension cord. 
     A female electrical receptacle is coupled to a second end of the cord member and electrically connected to the plurality of electrical wires of the cord member. Further, a female plug receiving member is fixedly coupled to and envelops the female electrical receptacle, the female plug receiving member including a flexible wall having a domed configuration and a female locking structure that defines a pair of receiver plug recesses, the flexible wall being constructed of a resilient material that is movable between a collapsed configuration allowing access to the pair of receiver plug recesses and a closed configuration not allowing access to the pair of receiver plug recesses. 
     Then, the first receiver portion and the second receiver portion of the male plug receiving member include a receiver portion locking structure having a pair of locking tabs extending away from front edges of the first receiver portion and the second receiver portion, respectively. The pair of receiver plug recesses is configured and operable to selectively receive the pair of locking tabs of the receiver portion locking structure, respectively. 
     Therefore, a general object of this invention is to provide a self-locking extension cord that extends electrical power to an associated power cord while securely holding electrical plugs from separating from one another. 
     Another object of this invention is to provide a self-locking extension cord, as aforesaid, that includes a male plug receiving member that opens to receive a male plug from an associated cord member and to hold the received plug in a locked engagement to the self-locking extension cord. 
     Still another object of this invention is to provide a self-locking extension cord, as aforesaid, that has an adjustable metal cord that is more durable and water resistant than a traditional extension cord. 
     Yet another object of this invention is to provide a self-locking extension cord, as aforesaid, that is cost effective to produce and to purchase. 
     Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a self-locking extension cord according to a preferred embodiment of the present invention; 
         FIG. 2  is another perspective view of the self-locking extension cord as in  FIG. 1  in use with an associated tool having an associated power cable; 
         FIG. 3  is an isolated view on an enlarged scale taken from  FIG. 1  illustrating the male and female receiving members coupled together; 
         FIG. 4  is a side view of the illustration as in  FIG. 3 ; 
         FIG. 5  is a fragmentary view of the illustration of  FIG. 3 , illustrated with female and male receptacles mated together; 
         FIG. 6  is a fragmentary view as illustrated in  FIG. 5  with the female and male receptacles removed for clarity; 
         FIG. 7  is another side view of male and female receiving members coupled together; 
         FIG. 8  is a fragmentary view of the illustration as in  FIG. 7 , illustrated with female and male receptacles mated together; 
         FIG. 9  is an end view of the self-locking extension cord as in  FIG. 1 , illustrated rotated in a first direction; 
         FIG. 10  is a fragmentary view of the self-locking extension cord as in  FIG. 10 ; 
         FIG. 11  is an end view of the self-locking extension cord as in  FIG. 1 , illustrated rotated in a second direction; 
         FIG. 12  is a fragmentary view of another end view of the self-locking extension cord as in  FIG. 1 ; 
         FIG. 13  is an isolated view on an enlarged scale taken from  FIG. 1 , illustrated with the male plug receiving member in an open configuration; 
         FIG. 14  is a plan view illustrating operation of the male plug receiving member according to the present invention; 
         FIG. 15  is an exploded view of the female receptacle side of the self-locking extension cord as in  FIG. 1 ; 
         FIG. 16  is an exploded view of the male receptacle side of the self-locking extension cord as in  FIG. 1 ; 
         FIG. 17  is a side view illustrating the female plug receiving member separated from the male plug receiving member as in  FIG. 1 ; 
         FIG. 18  is a side view illustrating the female plug receiving member partially coupled to the male plug receiving member; 
         FIG. 19  is a side view illustrating the female plug receiving member completely coupled to the male plug receiving member; 
         FIG. 20  is another end view of the present invention; 
         FIG. 21  is a sectional view taken along line  21 - 21  of  FIG. 20 ; 
         FIG. 22  is a sectional view taken along line  22 - 22  of  FIG. 20 ; 
         FIG. 23  is a perspective view of an electrical socket having locking structures for use with the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A self-locking extension cord according to a preferred embodiment of the present invention will be described in detail with reference to  FIGS. 1 to 23  of the accompanying drawings. The self-locking extension cord  10  includes a cord member  20 , a male electrical receptacle  26 , a female electrical receptacle  26 , and a male plug receiving member  30  removable from the extension cord member  20 . 
     The self-locking extension cord  10  has the general appearance of a traditional extension cord for extending the distance for delivery of electrical power to a remote electrical cord, appliance, tool, or the like. However, the self-locking extension cord  10  includes structures for preventing electrical plugs from becoming separated in use which, obviously, causes power delivery to be broken. The self-locking extension cord  10  also provides an adjustable metal cord construction that is durable and virtually impermeable to exposure of internal wires to water intrusion. 
     More particularly, the cord member  20  has an elongate construction having an outer layer that may be constructed of a partly flexible metal or metal-banded material. For instance, the cord member  20  is durable in harsh construction environments and still has flexibility to be shaped by a user as needed to move around corners or other objects. The extension cord member  20  may include a continuous side wall so as to define an interior channel for containing a plurality of conductive electrical wires. 
     The cord member  20  includes a first end  22  and a second end  24  opposite the first end  22 . Male and female electrical receptacles are coupled to the opposed ends, respectively. Specifically, a traditional male electrical receptacle  26  may be fixedly and electrically connected to the first end  22  of the cord member  20 . The male electrical receptacle  26  include 2 or 3 outwardly extending prongs intended for connection to an electrical wall socket or to a female electrical receptacle, such as for delivery electrical current to a remote extension cord, tool, or the like. Further, a generally traditional female electrical receptacle  28  is fixedly and electrically connected to the second end  24  of the cord member  20  with electrical current being carried via the plurality of electrical wires. 
     Next, the self-locking extension cord  10  includes a male plug receiving member  30  and a female plug receiving member  40 —the two structures having both similarities to one another as well as significant inventive differences as will be described later. The male plug receiving member  30  may be selectively and removably coupled to the first end  22  of the cord member  20  and includes a first receiving portion  31  pivotally and selectively coupled to a second receiving portion  32 . The male plug receiving member  30 , therefore, may be secured about the male electrical receptacle  26  of the self-locking extension cord  10  ( FIG. 1 ) or about an auxiliary male plug of an associated extension cord, tool  12 , or the like. More particularly, the first receiving portion  31  may have a generally hemispherical configuration and defines an interior area operable to receive a portion of a male electrical plug. The male plug receiving member  30  may also include a second receiving portion  32  having a generally hemispherical configuration and that defines an interior area operable to receive another portion of a male electrical plug. The male plug receiving member  30  is pivotally movable, such as via a hinge  33 , between an open configuration operable to receive the male electrical plug therein (or allow its removal) ( FIG. 12-14 ) and a closed configuration that captures the male electrical plug and does not allow its removal therefrom ( FIG. 15 ). The male plug receiving member  30  may also include O-rings  35  or other seals so as to make the housing water-tight and impermeable ( FIG. 12 ). The seal ring  36  of the male plug receiving member  30  is shown in  FIG. 15 . Further, the male plug receiving member  30  may include a fastener such as a clasp  34  for holding the receiving portions at the closed and temporarily locked and closed configuration ( FIGS. 1 and 13 ). 
     By contrast, the female plug receiving member  40  is fixedly coupled to the second end second end  24  of the extension cord member  20  and surrounds or envelopes the female electrical receptacle  26 . The female plug receiving member  40  may include an outer wall constructed of a flexible material having a generally dome shaped configuration. In other words, the outer wall may include a plurality of ribs  42  or ridges ( FIG. 4 ) that may be flexed and are resilient to return to their normal shape. The female plug receiving member  40  is most narrow at its attachment to the cord member  20  and has an open end ( FIG. 1 ) opposite the narrow end. The flexible construction enables the female plug receiving member  40  to move between a collapsed configuration (essentially “open”) giving access to receiver plug recesses  46  and a closed or resilient configuration not allowing access to the recesses  46  as will be described later. In other words, the female plug receiving member  40  can be “peeled back” to enhance usage for locking. The female plug receiving member  40  may also include O-rings or a rubber sealant  44  for sealing out water ( FIG. 6 ), including a female sealing ring  48 . 
     Now, both the male plug receiving member  30  and female plug receiving member  40  including locking structures so that the two may be locked together or separated. More particularly, the female plug receiving member  40  includes a front wall having a female locking structure defining at least a pair of receiver plug recesses  46  ( FIGS. 1 and 9 ). Similarly, the male plug receiving member  30  includes a front face having a male locking structure that includes at least a pair of locking tabs  37  or similar flanges that extend outwardly ( FIGS. 1 and 12 ). It is understood that the recesses  46  are dimensioned to selectively receive corresponding locking tabs  37  in a fastened or locking arrangement that is not easily separated in use ( FIG. 7 ), thus, keeping male and female plugs locked together ( FIG. 5 ). 
     Respective locking tabs  37  are included in respective recesses  46  in a friction fit engagement. Preferably, however, each recess  46  may have a bent configuration beneath its surface, such as an L-shaped interior space. Correspondingly, each locking tab  37  may also have a correspondingly bent or L-shaped configuration operably received by a corresponding slot and then rotated and turned between locked and unlocked configurations. 
     In use, the self-locking extension cord  10  has a single structure but is capable of multiple functionalities. First, the metal outer wall of the extension cord member  20  may have a metal construction, is still flexible, but is durable and water-resistant or even water proof. The self-locking extension cord  10  has a male electrical receptacle  26  and a female electrical receptacle  26  that may be plugged into a wall socket  14  for delivering electricity to an associated extension cord or associated tool  12  or the like ( FIG. 2 ). It will be understood that the wall socket may include locking structures substantially similar to those described above that are operable to prevent the self-locking extension cord  10  from becoming dislodged from the socket  14 . In addition, the male plug receiving member  30  may be removably coupled to surround either the male electrical receptacle  26  of the self-locking extension cord  10  ( FIG. 1 ) or the male plug of another extension cord, tool, or the like ( FIG. 2 )—either way, allowing a twist-locking secure hold of male and female plugs as described above. 
     It is understood that while certain forms of this invention have been illustrated and described, it is not limited thereto except insofar as such limitations are included in the following claims and allowable functional equivalents thereof.