Patent Publication Number: US-6217366-B1

Title: Releasable cord coupler

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. Provisional Patent Application No. 60/108,503 filed Nov. 16, 1998 titled Releasable Cord Coupler. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the field of devices for securing electrical connectors, such as the male and female ends associated with power conducting cords used for extension cords and power tool electrical cords and the like, in assembled, united or mated engagement so that the plugs are prevented from being accidentally separated. 
     BACKGROUND OF THE INVENTION 
     It is an identified problem in the prior art that male and female plugs on the ends of power conductors such as electrical extension cords and power tool electrical cords and the like may be accidentally separated if the junction between the cords is pulled under tension without some sort of restraining device coupling the male and female plugs together in mated engagement. 
     It is known that most power tools and heavy duty appliances include a relatively short power cord or rigid receptacle having a pronged male electrical connector at the end thereof. Typically the ends of the power cords are the only means provided by which extension cords may be connected to the power cords to provide power to the tools. Realistically, power tools are routinely used with extension cords and a user while moving about, for example at a work site, will quite often reach an outer limit of the range afforded by the extension cord and will inadvertently pull on the power tool thereby separating the junction between the power tool cord and the extension cord. More aggravatingly, a junction between connected extension cords removed from the location of the user requires the user to walk across the job site to locate separated connectors between extension cords. 
     Quite apart from the aggravation and inefficiency of such a situation, the partial separation of electrical connectors is also potentially hazardous. Consequently, the need identified in the prior art and attempted to be solved in the prior art exists to releasably secure by means of a releasably mountable device, male and female electrical plugs in mated engagement. 
     In the prior art devices, U.S. Pat. No. 5,167,524 which issued to Falcon on Dec. 1, 1992, identifies many prior art attempts to solve the above problem as such devices existed in the published prior art up to 1991. The Falcon device itself is a coupling restraint assembly which includes a pair of generally identically configured U-shaped flexible mounting straps which are secured relative to each of the male and female connectors in opposing relationship with respect to one another using integrally formed locking tabs which are extendible through openings provided in each strap. The mounting straps are constructed so as to be used interchangeably on different types and sizes of power cords and electrical connectors. In the embodiment taught to be preferred by Falcon, a pair of selfbinding restraint straps are secured to two legs of one of the generally U-shaped mounting straps and are selectively extendible through openings in opposing leg portions of the adjacent mounting strap. The restraint straps are secured upon themselves by use of hook and loop releasable fasteners. 
     What is neither taught nor suggested, and which is an object of the present invention to provide, is a coupling device superficially similar in plan view profile to the Falcon device when laid flat, but one which is of simplified construction when compared thereto for ease of manufacture and of increased tensile load bearing capacity. Load bearing capacity is increased due to the lack of apertures formed as tensile load transfer couplings between a base portion to which are mounted a pair of generally parallel straps. The present invention has no such limitation, being formed of a unitary piece which may be cut out of a sheet in a “cookie-cutter” fashion as better described below. 
     Applicant is also aware of U.S. Pat. No. 5,336,107 which issued to Sheryll on Aug. 9, 1994 for a plug retention device. Sheryll discloses a device for retaining an electrical plug and extension cord to another plug and extension cord by the use of fasteners strip elements secured to each cord adjacent to each plug by a circumferential clamp. With the electrical plug engaged with its corresponding socket, mechanical interacting fastener elements that engage each other when in the assembled state maintain the plug in the socket. It is taught that the fastening elements may be mushroom-shaped fasteners sold under the trademark Dual Lock or other forms of interacting article elements of the type the subject of the U.S. Pat. Nos. 3,192,589 and 3,266,113. What is neither taught nor suggested is a coupler adapted for use in storing a coiled extension cord, the Sheryll device also being of a molded plastic design not well adapted for being formed in a unitary piece cut out from a sheet in a “cookie-cutter” fashion. 
     SUMMARY OF THE INVENTION 
     In summary, the cord coupler of the present invention includes a flexible planar first sheet of hook and loop fastener material. A first side of the first sheet includes hook material of the hook and loop fastener material. An opposite second side of the first sheet includes loop material of the hook and loop fastener material. The first sheet is formed into at least three portions. A first portion is elongate in a first direction from a first end to an opposite second end. A second portion is elongate in a second direction from a first end to an opposite second end. A third portion is elongate in a third direction from a first end to an opposite second end. 
     The first direction is perpendicular to the second and third directions. The second and third directions are parallel. The second portion is adjacent the third portion. The first ends of the second and third portions are formed integrally with the first end of the first portion. 
     A first plug on one end of a first electrical cord may be laid between the second and third portions so as to dispose a coupling end of the first plug away from the first portion and so as to lay the first electrical cord perpendicularly across the first portion. The first portion may be wrapped around the first electrical cord so as to releasably fasten the first end of the first portion to the second end of the first portion thereby forming a collar secured on the first electrical cord behind the first plug. The wrapping of the first portion around the first electrical cord oppositely rotates the second and third portions relative to each other into generally opposed facing relation on opposite sides of the first plug. The second and third portions are thus positioned either for releasable fastening to corresponding releasable fasteners on a second plug when mated to the first plug, or for securing the first electrical cord, when coiled, to the first plug by wrapping and releasably securing the second and third portions around coils of the first electrical cord when coiled. 
     The corresponding releasable fasteners on the second plug may be second and third portions of a second sheet substantially identical to the first sheet. The second sheet is mounted to the end of the second electrical cord behind the second plug by wrapping a first portion of the second sheet around the second electrical cord behind the second plug. The second portions and the third portions of the first and second sheets may be overlapped into releasably fastened engagement so as to releasably secure the first plug coupled to the second plug. 
     Alternatively, the corresponding releasable fasteners on the second plug may be strips of releasable fastener material mounted directly onto opposite sides of the second plug. In this case, the second plug may be an electrical plug rigidly mounted to an appliance such as a hand tool. Advantageously, the first sheet is, or the first and second sheets are, double-sided hook and loop material or equivalent having solely hook pile or equivalent on the first side, and having solely loop pile or equivalent on the second side. The sheet or sheets may be cut to shape by a cookie-cutter method from a bulk supply of the double-sided hook and loop material. 
     In one aspect of the present invention, at least one stress reduction cut-out is formed in the first sheet between the first ends of the first, second and third portions. This may include a first stress reduction aperture between the first ends of the second and third portions so as to form one end of an elongate split running along the length of, and between, the second and third portions. The second and third portions may be, but are not necessarily immediately adjacent to each other. 
     The stress reduction cutouts may further include oppositely disposed, substantially semi-circular notches formed in opposite sides of the first ends of the second and third portions immediately adjacent the first end of the first portion. The first stress reduction aperture may be substantially circular. 
     In terms of dimensions, defining the first, second and third portions as having corresponding first, second and third lengths, the first length is generally equal to the second and third lengths. Defining the first, second and third portions as having corresponding first, second and third widths, measured lying in a plane of the sheet, the first width may be less than the second and third widths and the second and third widths may be substantially equal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is, in plan view, the coupler of the present invention. 
     FIG. 1 a  is a pair of the couplers of FIG. 1, in a slightly different embodiment, being formed from a single sheet of material. 
     FIG. 2 is, in exploded perspective view, a pair of couplers of the present invention being mounted onto the ends of electrical cords. 
     FIG. 3 is, in partially exploded perspective view, the opposed facing couplers of FIG. 2 being mated one onto the other. 
     FIG. 4 is, in perspective view, the coupler of the present invention being used in its alternative application to store a coiled electrical cord. 
     FIG. 5 is, in partially exploded perspective view, a coupler of the present invention being mounted to a rigid appliance. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As best seen in its open position in FIGS. 1 and 2, coupler  10  has a collar-forming first portion  12 . When coupler  10  is laid flat, first portion  12  extends generally along axis A. It is integrally formed at one end thereof with a pair of elongate generally parallel portions, namely, second portion  14  and third portion  16 . Second portion  14  and third portion  16  extend along their respective longitudinal axes B and C, where advantageously, axis A is generally perpendicular to axes B and C. 
     Goosenecks  18  and  20  may, in one preferred embodiment, be formed at intersections between second portion  14  and third portion  16  respectively with first portion  12 . Goosenecks  18  and  20  may be formed by hemispherical cut-outs  22  and  24  on opposite sides of, respectively, second portion  14  and third portion  16  and by circular cut-out  26  formed between second portion  14  and third portion  16 . 
     Goosenecks  18  and  20  allow for rotation .of second portion  14  and third portion  16  about their respective longitudinal axes B and C so as to advantageously allow for alternative use of these portions as described below. 
     FIG. 1 illustrates the coupler of the present invention laid flat. As may be better appreciated by reviewing FIGS. 2 and 3 the coupler  10  when laid flat is a thin generally planar sheet which may be thought of as L-shaped. In the preferred embodiment, coupler  10  is cut for example by means of a cookie-cutter manufacturing process, from sheets of double sided hook and loop fastening material such as manufactured and sold under the trademark Velcro™ or from sheets of substrate material having Dual-Lock mushroom-type fasteners or other stud-shaped fasteners or the like. In the Velcro™ embodiment, the hook and loop double sided sheet material has the loop surface on one side of the sheet and the hook surface on the opposite side of the sheet. Hereinafter, references to hook and loop fasteners and double-sided hook and loop material is intended to include, without limiting, other similarly functioning releasable fastening material available in double-sided flexible sheet form. 
     As seen in FIG. 2, first portion  12  may be rotated in direction D so as to form the collar seen in FIG. 3 formed around electrical cord  28  by wrapping one end of first portion  12  over the opposite end. In the preferred embodiment, second and third portions  14  and  16  respectively, are formed side by side so that by wrapping the elongate free end  12   a  of first portion  12  over the end  12   b  adjacent goosenecks  18  and  20 , second portion  14  and third portion  16  are rotated about the longitudinal axis E at the ends of the electrical cord adjacent mate plug  30  and female plug  32 . The end result may be thought of as resembling “rabbit cars” in shape. 
     Axis E is the coupling axis parallel to which the prongs on male plug  30  are inserted into the corresponding female receptacles in female plug  32  as male plug  30  and female plug  32  are mated by translation in direction F to end up in a coupled position as seen in FIG.  3 . With the collar formed by wrapping first portion  12 , second portion  14  and third portion  16  are rotated about axis E so as to be radially spaced from each other about axis E, and, depending on the diameter of electrical cord  28 , advantageously end up in generally opposed relation splayed on either side of the corresponding plug, whether it be male plug  30  or female plug  32 . 
     With one coupler  10  so mounted to electrical cord  28  adjacent male plug  30 , and another coupler  10  mounted on electrical cord  28  adjacent female plug  32 , so that the pair of couplers  10  are in opposed facing relation, mating translation in direction F of male plug  30  relative to female plug  32  positions the second and third portions of both couplers so that they may be overlapped, a second portion on a first coupler overlapping a third portion on the second coupler and the third portion on the first coupler overlapping the second portion on the second coupler, or vice versa. In this way, the hooked surface on one of the couplers will overlap the looped surface on the other coupler. When pressed together, the respective second portion on the first coupler and the third portion on the second coupler, and third portion on the first coupler and second portion on the second coupler are releasably mated. This then utilizes the significant shear resisting strength of a hook and loop fastener along the length of the second and third portions to thereby resist tensile pulling apart of the male and female plugs in a direction opposite to direction F. 
     The overlapping is best understood by the illustration of FIG. 3 where second portion  14  is shown, by way of example, as having a looped surface  14 a and where third portion  16  is shown as having a looped surface  16   a . A first coupler  10  is ready for hook and loop releasable mating with a second coupler labelled  10 ′. Second coupler  10 ′ has then its third portion  16 ′ with its hooked surface, opposite to its looped surface  16   a ′, outwardly facing so as to releasably mate with looped surface  14   a  on second portion  14  by overlapping second portion  14  in direction  0  onto third portion  16 ′. Similarly, third portion  16  is overlapped onto second portion  14 ′ by overlapping in direction G so as to releasably mate looped surface  16   a  with the hooked surface of second portion  14 ′ opposite to looped surface  14   a.    
     Once first coupler  10  is releasably mated with second coupler  10 ′, pulling apart of male plug  30  from female plug  32  is resisted by the sheer strength of the hook and loop mating between second portion  14  and third portion  16 ′ and between third portion  16  and second portion  14 ′. The tensile loads during such pulling are taken up by first portions  12  and  12 ′ sliding along electrical cord  28  so as to snug against the base ends  30   a  and  32   a  respectively of male plug  30  and female plug  32 . The load is then transferred through goosenecks  18  and  20  so as to be born in the aforesaid mating between the first and second portions  14  and  16  on coupler  10  and the corresponding second portion  14 ′ and third portion l 6 ′ on second coupler  10 ′. 
     In the embodiment where goosenecks are formed by cut-outs  22 ,  24  and  26 , advantageously the cut-outs are smoothly contoured so as to avoid stress concentration points such as would be formed by slits or other crack-like apertures cut into the sides of the second and third portions. Thus during heavy industrial usage over extended periods of time, the hook and loop sheet fabric of which coupler  10  and coupler  10 ′ is formed is much less likely to tear. 
     For the coupling usage of coupler  10  seen in FIGS. 2 and 3, it being understood that coupler  10 ′ is identical to coupler  10 , it is not necessary that in fact the second and third portions be formed with goosenecks. However, goosenecks  18  and  20  are advantageous in the application illustrated in FIG.  4 . As seen in FIG. 4, coupler  10  may be used to assist in bundling of electrical cord  28  when electrical cord is coiled ready to be stored after usage. Goosenecks  18  and  20  allow the second portion  14  and the third portion  16  to be more easily rotated about their corresponding longitudinal axes B and C by 90 degrees so that they may be wrapped one over the other to encircle a coiled electrical cord  28 . Once so wrapped in releasable fastening thereover, when it is once again desired to use electrical cord  28 , second portion  14  is merely pealed back from its overlapped position mated onto third portion  16 . Coupler  10  is maintained in proximity to the plug, seen in FIG. 4 to be male plug  30  although not necessarily so, by leaving first portion  12  formed as a collar wrapped around the end of electrical cord  28  adjacent the plug. 
     As seen in FIG. 5, a single coupler  10  may be employed for releasable mating of female plug  32  on extension cord  28  with a rigid male electrical receptacle  34  such as are found rigidly mounted to appliances such as gardening tools including electric lawnmowers, hedge trimmers and the like, or other power tools. By way of example, in the embodiment of FIG. 5, male electrical receptacle  34  is formed in one end of the handle  36  of an electric hedge trimmer. Maintaining female plug  32  on the prongs of male receptacle  34  can be problematic. Thus, strips of Velcro™  38  are fastened by adhesive to the exterior side walls of male receptacle  34 , and the second and third portions  14  and  16  of coupler  10  then mounted to the Velcro™ strips to hold plug  34  in mated engagement with the prongs of male receptacle  34 . It is understood that coupling according to this embodiment applies to all rigid appliances having rigid male receptacles, and also to electrical outlet boxes where strips of Velcro™ may be adhered or otherwise fastened to the box. 
     In preferred embodiments not intended to be limiting, first portion  12  may be  4  inches long and ½ inch wide, second and third portions  14  and  16  may be either 4 inches or 4 ½ inches long and either ⅞ inches or 1 inch wide, gooseneck cut-outs  22  and  24  may have a radius of either {fraction (3/16)} of an inch or ¼ of an inch, and, correspondingly, cut-out  26  may have a diameter of either ⅜ of an inch or ½ of an inch. An extra tab end  12   c  may extend from the end of first portion  12  adjacent cut-out  22 . 
     As seen in FIG. 1 a , the shape of coupler  10  lends itself to efficient cutting of multiple couplings  10  from a single sheet  8  of double-sided hook and loop material by a “cookie-cutter” manufacturing process. 
     As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof Accordingly, the scope of the invention is to be construed in accordance with tie substance defined by the following claims.