Patent Publication Number: US-8109778-B2

Title: Electrical connector lock

Description:
BACKGROUND OF TILE INVENTION 
     This invention relates to electrical connectors and, more particularly, to an electrical cord plug assembly for use in preventing the separation of joined electrical plug and electrical socket. 
     Electrical cord connector assemblies consisting of a male connector, or plug, and a female connector, or socket, are conventionally used in a multitude of industrial and household applications. Both male connectors and female connectors are connected to a discrete length of cord of cable to provide an electrical connection between appliances, tools, sources of power, etc. 
     The male connector portion of such an assembly has a pair of electrically-conductive prongs and sometimes a ground prong. The socket part of the assembly includes a housing with corresponding openings to receive the prongs of the male connector portion. The housing is provided with electrical contacts for establishing electrical connection between the electrical devices, tools, and the like. 
     One of the major problems with conventional electrical connector assemblies is inability to secure the male connector portion in the housing and prevent the plug from being disconnected from the socket housing. Conventional assemblies establish only frictional engagement between the plug and the socket; a pulling force applied to the cable can and oftentimes does, disengage the plug from the socket. The pulling force may be applied inadvertently when moving an electrical device beyond the extent of the interconnected electrical conduit. Alternatively, children or pets may unintentionally disconnect these electrical connections. 
     One of the industry responses to the problem was provision of a box-like enclosure that is adapted for positioning about the plug and socket connectors and restricting lateral movement of the plug and the socket connector members. The box has a hinged lid that is locked by a flap engaging within a slot formed in the wall of the box. However, such solution is not without problems, such as difficulty in manipulation, especially for people with limited dexterity, extra bulk added to the connectors and the like. 
     The present invention contemplates elimination of drawbacks associated with conventional solutions and provision of an electrical connector lock for use with electrical assemblies having a pronged male connector portion. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the invention to provide an electrical connector lock configured for use with pronged male connectors. 
     It is another object of the invention to provide an electrical connector lock that is mounted substantially entirely within the housing of the female receptor. 
     It is a further object of the invention to provide an electrical connector lock that can be activated and deactivated by depressing actuator button(s) mounted on exterior of the housing of the female receptor. 
     These and other objects of the invention are achieved through a provision of a locking female electrical receptor assembly for use with an electrical male connector provided with electrically conductive prongs having punched or drilled apertures. The female receptor has a housing, an end face of which is provided with slots configured to receive the prongs of the male connector, or male plug. A pair of spaced-apart electrically conductive contact members are mounted in the housing in alignment with the slots, each of the contact members being provided with a channel sized and configured to receive a male prong therein. The contact members each have a transverse opening that is aligned with the aperture in the male plug prongs when the male connector is engaged with the female receptor. 
     A locking means is mounted in the housing for locking the male connector and the female receptor, the locking means being configured to move between a normally locked position extending through the openings of the contact members and an unlocked position away from the contact members. The locking means is configured to also extend through apertures of the prongs when the male connector is engaged with the female receptor. A depressible actuator means is operationally connected to the locking means for moving the locking means into an unlocked position. The actuator means can be one or more buttons accessible from exterior of the housing and spring-loaded for normally urging the locking means into a locked position. The actuator button can be activated by an actuator spring or by the tension of a leaf spring. 
     The locking means can be in the form of a pair of caps with conical projections that engage the openings in the contact members and the apertures in the prongs. The locking means can also be in the form of a U-shaped leaf spring with opposing spring leaf portions that carry projections. The projections engage the openings on the contact members and the apertures in the prongs to lock the male plug connector and the female receptor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the drawings, wherein like parts are designated by like numerals, and wherein 
         FIG. 1  is a perspective view of two electrical corded connectors, with the female connector carrying a locking member. 
         FIG. 2  is a perspective view illustrating engagement of the two connectors, while the locking member is depressed. 
         FIG. 3  is a perspective view illustrating engagement of the male and female connectors in an unlocked position. 
         FIG. 4  illustrates the two electrical connectors in a locked position. 
         FIG. 5  is an exploded view of the female connector. 
         FIG. 6  is a cross sectional view of a depressible locking member, with the cap in an unlocked position. 
         FIG. 7  is a cross sectional view of a depressible locking member, with the cap in a locked position. 
         FIG. 8  is a perspective view of the locking member, with the caps in an unlocked position. 
         FIG. 9  is a perspective view of the locking member, with the caps in a locked position. 
         FIG. 10  is a perspective view of the depressible locking member. 
         FIG. 11  is a schematic view illustrating movement of a prong of the male connector within the housing of the female connector, while the cap is in an unlocked position. 
         FIG. 12  is a schematic view illustrating movement of a prong of the male connector within the housing of the female connector, while the cap is in a locked position. 
         FIG. 13  is a perspective view of a portion of a female connector housing showing the depressible lock member and a main compression spring. 
         FIG. 14  is a plan view of the two connectors, with the locking device according to the second embodiment of the present invention in a locked position. 
         FIG. 15  is a plan view of the two connectors, with the locking device according to the second embodiment of the present invention in an unlocked position 
         FIG. 16  is a plan view of the female receptor according to the second embodiment of the present invention in an unlocked position. 
         FIG. 17  is a plan view of the female receptor according to the second embodiment of the present invention in a locked position. 
         FIG. 18  is a plan view of the locking device according to the third embodiment of the present invention in an unlocked position. 
         FIG. 19  is a plan view of the locking device according to the third embodiment of the present invention in a locked position 
         FIG. 20  is a plan view of the locking device according to the fourth embodiment of the present invention in an unlocked position. 
         FIG. 21  is a plan view of the locking device according to the fifth embodiment of the present invention in a locked position 
     
    
    
     DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings in more detail, and in particular to  FIGS. 1-13 , the first embodiment of the present invention can be seen in use with an electrical male connector plug  10  having conventional insulated electrical cord  11  and a plurality of outwardly conductive extended prongs  12  and  14 , and a ground prong  15 . The prongs  12  and  14  contain prong apertures  16  and  18 , respectively. The locking assembly of the present invention is configured to lockingly engage the prong apertures  16 ,  18  when the male electrical cord plug  10  is inserted a predetermined distance within the female receptor  20  and prevent disengagement of the male connector plug  10 . 
     Electrical female receptor  20  is connected to a typical electrical line or cord  21  having an exterior electrical insulation. The male plug  10  and female receptor  20  can be attached to any conductive electrical lines, such as in connection with extension cords to the insulated cords  11 ,  21 . 
     The female receptor  20  is formed as a molded receptor housing  30  from a suitable material, such as a molded plastic and the like, that is electrically non-conductive. An end face  32  of the receptor  20  is provided with a pair of plug holes or slots  33 ,  34  and an slot  35  for the ground prong  15 . An upper face  36  of the housing  30  is provided with an opening through which a locking assembly actuator button  37  extends. The operation of the locking assembly will be described in more detail hereinafter. 
     Turning now to  FIG. 5 , the female receptor  30  is shown in an exploded view. For ease of illustration, the housing  30  is shown comprising two halves,  41  and  42 . A central slot  45  is formed in the housing  30  to receive an electrical cable  46  with wires  47 ,  48 . The wires  47 ,  48  diverge and engage electrical contact members  49 ,  50 , respectively. Each of the contact members  49 ,  50  is formed as a U-shaped body with a channel, which is configured to receive the prongs  12  and  14 . The contact members  49 ,  50  are formed from an electrically-conductive material to allow electrical current to pass between the male connector  10  and the female receptor  20 . 
     Each of the contact members  49 ,  50  is provided with a transverse opening  51 ,  52 , respectively. A pair of cylindrical hollow caps  53 ,  54  is positioned between the contact members  49 ,  50 . Each cap  53  and  54  comprises a conical portion  55 , which extends outwardly from the cap body (see  FIGS. 11 and 12 ). The conical portion  55  is sized and configured to extend through the openings  51 ,  52  of the contact members  49 ,  50  when the locking assembly is in a locked position. A compression spring  56  is mounted between the caps  53 ,  54 , partially fitting inside the hollow bodies of the caps  53 ,  54 , as shown in  FIGS. 11 and 12 . 
     The depressible locking assembly button  37  is mounted in the housing  30  and extends through the opening formed in the upper face  36 . The button  37  comprises a generally cylindrical hollow body sized and configured to receive an actuating spring  66  therein. The actuating spring  66  urges, at one end against the housing  30 , and at another end—against an inner shoulder  58  ( FIGS. 5 and 7 ) formed in the interior of the button  37 . If desired, the actuating spring  56  may be sized to almost entirely fit in the body of the button  37 , as shown in  FIG. 9 . 
     The exterior of the button  37  is provided with an annular flange  60  that prevents the button  37  from disengaging from the housing  30 . A locking bar  62  is affixed to an exterior surface  61  of the button  37 , extending longitudinally along the length of the button  37 , from an inner end  64  of the button  37  to the annular flange  60 . The longitudinal axis of the locking bar  62  is perpendicular to the direction of movement of the caps  53 ,  54  when the caps move between locked and unlocked positions under the force of the compression spring  56 . 
     The locking bar  62  is provided with a first groove  68  configured to frictionally engage the caps  53 ,  54  when the locking assembly is an unlocked position. As shown in  FIGS. 6 and 8 , when the caps  53 ,  54  are positioned in the groove  68 , the button  37  can move axially in the direction of arrow  70  when depressed by a user. When the button  37  is depressed, the caps  53 ,  54  are close together and allow the prongs  12 ,  14  to move freely within the contact members  49 ,  50  ( FIG. 11 ). 
     When the button  37  is released the caps  53 ,  54  are forced to move from the groove  68  along the locking bar  62 . A second groove  72  is formed along the locking bar  62 . An outwardly extending ridge  74  is formed between the first groove  68  and the second groove  72 . 
     The ridge  74  forces the caps  53 ,  54  to separate, with the compression spring  56  keeping the caps  53 ,  54  apart (see,  FIG. 9 ). At the same time, the actuating spring  66 , being released from compression, forces the cap  37  outwardly from the housing  30 , and the caps  53 ,  54  move into the second groove  72 . 
     The conical portions  55  of the caps  53 ,  54  enter the openings  51 ,  52  formed in the contact members  49 ,  50  and are forced into the openings  16 ,  18  formed in the prongs  12  and  14 , as shown in  FIGS. 7 and 12 . In this position, the male connector  10  cannot be disengaged from the female receptor  20 , and the two corded connectors are lockingly engaged. When the user desires to disconnect the male connector from the female receptor the user presses on the button  37 , causing the caps  53 ,  54  to retreat from engagement with the prongs  12  and  14  and move back into the first groove  68 . In this position, the prongs  12  and  14  can move freely in the axial direction within the contact members  49 ,  50 . 
     This embodiment of the invention requires that the button  37  be depressed by the user when the user wishes to engage the male connector plug with the female receptor. Once the button  37  is released it springs outwardly from the housing  30  and locks the caps  55  with the prongs  12 ,  14 , thus preventing disengagement of the two corded electrical connectors. 
     Turning now to  FIGS. 14-17 , the second embodiment of the locking assembly of the present invention is shown in detail. In this embodiment, a generally U-shaped leaf spring  80  is positioned in the housing  30 . The leaf spring  80  comprises a pair of spaced-apart leaf spring portions  82 ,  84  connected by an arcuate bridge  86 . The bridge  86  can have a U-shaped or V-shaped cross-sections and other configurations, depending on the manufacturer&#39;s preference and the strength of the leaf spring portions  82 ,  84 . 
     A projection  83  is secured adjacent a free end  85  of the leaf spring portion  82 . A similar projection  87  is secured adjacent a free end  88  of the second leaf spring portion  84 . The free ends of the leaf spring portions  82 ,  84  extend between the contact members  49 ,  50 . The projections  83  and  83  are sized and configured to extend through openings formed in the contact members  49 ,  50  and openings  16  and  18  formed in the prongs  12 ,  14 , respectively. 
     A pair of depressible actuator buttons  90 ,  92  is secured with the leaf spring  80 , one for each leaf spring portion. The buttons  90 ,  92  extend in aligned relationship from the housing  30  through corresponding openings. The buttons  90  and  92  are located a distance from the projections  83 ,  87 , approximately midway along the length of the leaf spring portions  82 ,  84 .  FIGS. 14 and 16  illustrate a normally locked position of the female receptor  20 , with the projections  83  and  87  blocking insertion of the prongs  12 ,  14  into the slots of the female receptor  20 . However, when the actuator buttons  90 ,  92  are depressed they push the leaf portions  82 ,  84  closer together, causing the free ends  85  and  88  of the leaf portions to move toward the axial center of the housing  30 . In this position, the projections  83  and  87  move away from the contact member  49 ,  50  and open the passageway for the prongs  12 ,  14 . The prongs  12 ,  14  can now be inserted into the female receptor, and the plug  10  connected to the female receptor  20 . 
     Releasing of the buttons  90 ,  92  will again move the leaf portions  82 ,  84  apart, cause the projections  83 ,  87  engage with the openings in the contact members and the prongs  12 ,  14 . 
     In this embodiment, similar to the second embodiment, the bridge  103  connecting the leaf spring portions  102  and  104  can be arcuate, U-shaped, V-shaped in cross section and can have other shapes. 
       FIGS. 18 and 19  illustrate a third embodiment of the invention, wherein free ends of the leaf spring portions  102 ,  104  are located outside of the contact members  49 ,  50  and engage the openings formed in the contact members and the prongs from the outside. Each of the leaf spring portions  102 ,  104  is provided with a corresponding projection  100 ,  101 . 
     Push buttons  106 ,  107  are secured to the spring leaf portions  102 ,  104  a distance from the projections  100 ,  101 . In this design, when the actuator buttons  106 ,  107  are depressed, the projections  100 ,  101  are forced out of the openings in the prongs  12 ,  14  and the contact members  49 ,  50 . Release of the push buttons  106 ,  107  causes the leaf spring portions  102 ,  104  to return to their normally tensed position on opposite sides of the contact members  49 ,  50 . In this position, the projections  100 ,  101  enter through the openings formed in the contact members  49 ,  50  and the prongs  12 ,  14 , locking the male plug with the female receptor. 
       FIGS. 20 ,  21  illustrate the fourth and fifth embodiment of the invention, which is substantially similar to the third embodiment shown in  FIGS. 18 and 19 . However, in the fourth embodiment shown in  FIG. 20 , the bridge connecting leaf spring portions  112 ,  114  has an inverted U-shaped cross-section. In the fifth embodiment of  FIG. 21 , the bridge  116  connecting the leaf spring portions  118 ,  120  has a generally inverted V-shaped cross-section. 
     The operation of the locking assemblies of  FIGS. 20 and 21  is substantially similar to the operation of the locking assembly illustrated in  FIGS. 18 and 19 . In both embodiments, pressing on the actuator buttons  122 ,  124  forces to leaf spring portions  112 ,  114  or  118 ,  120  to move apart, removing the projections  113 ,  115  (or  119 ,  121 ) from engagement with the contact members and the prongs. Releasing of the actuator buttons  122 ,  124  returns the leaf spring portions into their normally tensed position and allows the projections to engage with the contact members and the prongs  12 ,  14 . 
     Persons having skill in the art will readily appreciate that numerous other configurations of the locking spring can be provided. Also, the locking springs can be substituted by compression springs and bars to effect the pushing action on the depressible locking buttons. Many other changes and modifications can be made in the design of the present invention without departing from the spirit thereof. We, therefore, pray that our rights to the present invention be limited only by the scope of the appended claims.