Patent Publication Number: US-2009239400-A1

Title: Safety receptacle with tamper resistant shutter

Description:
BACKGROUND 
     1. Field 
     The aspects of the disclosed embodiments generally relate to electrical protection devices, and particularly to an electrical receptacle with a protective shutter mechanism. 
     2. Background 
     Electrical receptacles are widely used in daily life. Common electrical receptacles do not provide protective features to prevent foreign objects from being inserted into the openings of the receptacle. As such, it can be relatively easy to insert objects such as paper clips, screwdriver blades or iron wire into the receptacle contact openings. Unfortunately, this can often result in electric shock, burns, or electrocution. 
     In one approach, the electrical receptacles in the wiring devices are equipped with shuttered openings that prevent the insertion of foreign objects into the receptacle contact openings. The mechanism comprises a spring element that pushes the plastic chock block element, shuttering the openings. One drawback to this approach is the shutters will open at the forced insertion of foreign object into only one opening, exposing a person to a shock hazard. It would be advantageous to provide a shutter mechanism that will not open, and block exposure to the receptacle contacts, upon the insertion of an object into only one of the openings. 
     SUMMARY 
     In one aspect, the disclosed embodiments are directed to an apparatus. In one embodiment, the apparatus includes a frame and a shutter device located within the frame, the shutter device being configured to simultaneously block openings for at least a hot and neutral connectors of an electrical receptacle when forces are unequally applied to the shutter device through openings corresponding to the at least hot and neutral connectors. 
     In another aspect, the disclosed embodiments are directed to an apparatus. In one embodiment, the apparatus includes a frame configured to be inserted into an electrical receptacle, a first shutter member slidingly mounted in the frame, the first shutter member having a first ramp member and a first receptacle blocking member, a second shutter member slidingly mounted in the frame, the second shutter member having a second ramp member located in front of the first blocking member and a second receptacle blocking member located behind the first ramp member and a first resilient member disposed between the first shutter member and the frame and a second resilient member disposed between the second shutter member and the frame wherein the first and second shutter members are configured to simultaneously block a neutral and hot opening of the electrical receptacle when a force is exerted on either of the first or second ramp members. 
     In yet another aspect, the disclosed embodiments are directed to an electrical receptacle. The electrical receptacle includes a housing for providing at least a hot and neutral receptacle to a power source, a cover attached to the housing having at least a first and second openings for allowing connection to a corresponding one of the hot or neutral receptacle, and a shutter device located within the housing, the shutter device being configured to block both the first and second openings when forces are unequally applied to the shutter device through the first and second openings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is an exploded component view of one example of the protective shutter assembly of the disclosed embodiments; 
         FIG. 2  is an axonometric view of a protective shutter assembly of the disclosed embodiments; 
         FIG. 3  is a side elevation view of the protective shutter assembly shown in  FIG. 2 ; 
         FIG. 4  is an end elevation view of the protective shutter assembly shown in  FIG. 2 ; 
         FIG. 5  is a plan view of the protective shutter assembly shown in  FIG. 2 ; 
         FIG. 6  is a plan view of an internal portion of one embodiment of a cover assembly for the protective shutter assembly of the disclosed embodiments; 
         FIG. 7  is a plan view of an internal portion of the cover assembly shown in  FIG. 6  including the protective shutter assembly of  FIG. 2  embodied therein; 
         FIG. 8  is a plan view of the external portion of the cover assembly shown in  FIG. 6  with the protective shutter assembly of  FIG. 2  embodied therein; 
         FIG. 9  is a cross-sectional view of one example of an electrical receptacle device including a protective shutter assembly with plug blades inserted into each of the receptacle openings; 
         FIG. 10  is a axonometric view of the electrical receptacle device including the protective shutter assembly shown in  FIG. 9  with plug blades inserted into each of the receptacle openings; 
         FIG. 11  is a cross-sectional view of the device of  FIG. 8  with only one plug blade inserted into only one receptacle opening; 
         FIG. 12  is a axonometric view of the device shown in  FIG. 11 ; 
         FIG. 13  is a plan view of an internal portion of an embodiment of a cover assembly; 
         FIG. 14  is a plan view of an internal portion of the cover assembly illustrated in  FIG. 13  with a protective shutter assembly shown in  FIG. 2  embodied therein; 
         FIG. 15  is a plan view of the external portion of the cover assembly shown in  FIG. 13  with a protective shutter assembly as shown in  FIG. 2  embodied therein; 
         FIG. 16  is a cross-sectional view of the device illustrated in  FIG. 15 , with plug blades inserted into each of the receptacle openings; 
         FIG. 17  is an axonometric view of the device illustrated in  FIG. 16 ; 
         FIG. 18  is a cross-sectional view of the device of  FIG. 15  with only one plug blade inserted into only one receptacle opening; 
         FIG. 19  is an axonometric view of the device of  FIG. 18 ; 
         FIG. 20  illustrates one example of a shutter member of a protective shutter assembly of the disclosed embodiments; and 
         FIG. 21  illustrates a side view of the shutter member shown in  FIG. 20 . 
         FIG. 22  is a cross-sectional view of the protective shutter assembly illustrated in  FIG. 2 . 
         FIG. 23  is a plan view of a shutter member assembly. 
         FIGS. 24 and 25  are illustrations of exemplary plug assemblies including the protective shutter assembly of the disclosed embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT(S) 
     Referring to  FIG. 1 , a protective shutter assembly  1  for an electric receptacle is shown. Although the embodiments disclosed will be described with reference to the embodiments shown in the drawings, it should be understood that the embodiments disclosed can be embodied in many alternate forms. In addition, any suitable size, shape or type of elements or materials could be used. 
     The aspects of the disclosed embodiments are directed to a protective shutter assembly for an electrical receptacle, which can be embodied in a cover assembly for the electrical receptacle. In one embodiment, a protective shutter mechanism in the protective shutter assembly shutters the corresponding receptacle opening, and will open only when plug blades are inserted into both receptacle openings at substantially the same time. It is a feature of the disclosed embodiments that the protective shutter assembly will only operate to allow the complete insertion of plug blades into the receptacle openings, when two plug blades are inserted into both openings in a balanced manner. This effectively prevents the insecurity that the shutters will open at the forced insertion of a foreign object into only one opening. 
     Referring to  FIG. 1 , in one embodiment, the protective shutter assembly  1  comprises a framed mechanism including two shutter members  29   a ,  29   b , a registration member  34 , and two resilient members  10   a ,  10   b . Each resilient member  10   a ,  10   b , which in one embodiment comprise springs, is disposed between a respective shutter member  29   a ,  29   b  and the registration member  34 . While the resilient members are shown as coil springs in the figures, in other embodiments the resilient members may be any suitable resilient members including, but not limited to, leaf springs and spring washers. Movement of each shutter member  29   a ,  29   b , with respect to the registration member  34 , will either compress or allow the extension of the corresponding resilient member  10   a ,  10   b.    
     Referring to  FIG. 20 , one example of a shutter member  29  is illustrated. As shown in  FIG. 20 , the shutter member  29  includes a spring registration protrusion  22 , a shutter ramp  24 , and spring registration blocks  21   a  and  21   b . In other embodiments, the spring may be registered against the shutter member  29  in any suitable manner such as through recesses. The shutter member  29  also includes a longitudinal retaining pocket  25  and longitudinal retaining orbit  26 , as shown in  FIG. 1 . The longitudinal retaining pocket  25  is configured to move in longitudinal retaining orbit  26  to prevent shutter members  29   a  and  29   b  from moving side to side. As also shown in  FIGS. 20 and 21 , the shutter member  29  also includes longitudinal retaining lip  23 , shutter blocking member  27  and registration pocket  28 . 
     In the embodiment shown in  FIGS. 1 and 22 , the base of the registration member  34  includes two polarity receptacle openings  32   a ,  32   b  and a shutter orbit or slot  30 . The slot  30  is configured to accept the longitudinal retaining lips  23  of the shutter members  29   a ,  29   b  for retaining the shutter members  29   a ,  29   b  within the registration member  34  while allowing sliding movement of the shutter members  29   a ,  29   b  within the registration member  34  as can be seen in  FIGS. 2 and 3 . The polarity receptacle openings  32   a  and  32   b  are generally configured to receive corresponding electrical blades or contacts. As illustrated in  FIG. 1 , the registration member  34  may also include recesses  26   b ,  26   c  for slidingly engaging the longitudinal retaining orbit  26  of a respective one of the shutter members  29   a ,  29   b . The size and configuration of the openings  32   a  and  32   b  can be configured to any suitable number or openings having any suitable size and shape. 
     In one embodiment, on each side or end of the registration member  34 , there is a side chamfer  35 , installation pocket  33  and spring registration hole  31  for easy installation and assembly of the shutter members  29   a  and  29   b , the resilient members  10   a ,  10   b  and the registration member  34  to form the protective shutter assembly  1  of the disclosed embodiments. 
       FIGS. 2 and 22  illustrates one example of a protective shutter assembly  1  with the shutter members  29   a ,  29   b  and resilient members  10   a ,  10   b  assembled within the registration member  34 .  FIG. 3  is a side view of the assembly  1  of  FIG. 2 , while  FIG. 4  is an end view of the assembly  1  shown in  FIG. 2 .  FIG. 5  is a top plan view of the assembly  1  shown in  FIG. 2 . 
       FIGS. 6 and 13  illustrate plan views of different examples of cover assemblies that can be used with the protective shutter assembly  1  shown in  FIG. 2 . It is noted that the cover assemblies may have any suitable configuration and should not be limited to those shown and described herein. As shown in  FIGS. 6 and 13 , embodied in the upper cover  46 ,  246  of the receptacle are a hot receptacle opening  44 ,  244 , a neutral receptacle opening  43 ,  243  and a grounding receptacle opening  45 ,  245 . The cover  46 ,  246  can also include an alignment key  42 ,  242  and two retaining walls  47 ,  247  to retain the protective shutter assembly  1  of  FIG. 2  in the cover assembly  46 ,  246 .  FIG. 7  illustrates one example of the protective shutter assembly  1  retained in the cover  46  of  FIG. 6 . 
     In one embodiment, the registration member  40 ,  240  fixes the protective shutter assembly  1  of  FIG. 2  in the cover  46 ,  246 . As shown in  FIGS. 24 and 25 , the installation latch  41 ,  241  is used to fix the cover  46 ,  246  to the base  50 ,  250  of the main body of the receptacle. In other embodiments the cover  46 ,  246  may be coupled, either removably or fixedly, to the main body  50 ,  250  in any suitable manner including, but not limited to, adhesives, ultrasonic welding or mechanical fasteners. 
       FIG. 8  is a plan view of the external portion of the cover assembly shown in  FIG. 6  with the protective shutter assembly of  FIG. 2  embodied therein. As shown in  FIGS. 8 and 9 , the receptacle assembly  800  includes complementary pairs of receptacle openings  43 ,  44  for exemplary purposes only. In alternate embodiments, a receptacle assembly  800  can include any suitable number of receptacle openings. 
       FIG. 9  is a cross-sectional view of one example of an electrical receptacle device, such as assembly  800  shown in  FIG. 8 , including a protective shutter assembly with plug blades  50   a ,  50   b  inserted into each of the receptacle openings  44 ,  43 , respectively. When a pair of plug blades  50   a ,  50   b  is inserted into each respective receptacle opening,  44 ,  43 , substantially simultaneously, the protective shutter assembly  1  is configured to allow the blades  50   a ,  50   b  to pass through the receptacle openings,  44 ,  43  as will be described in greater detail below. This allows the blades  50   a ,  50   b  to establish an electrical connection with a supply source or receptacles (not shown). 
     However, the aspects of the disclosed embodiments will effectively prevent the insertion of only one plug blade, or foreign object, into only one of the openings. When such an attempt is made, the protective shutter assembly  1  of  FIG. 2  will block both receptacle openings  43 ,  44 . 
     Referring also to  FIG. 22 , before the plug element  50   a  is inserted into one of the receptacles the shutter members  29   a ,  29   b  are in an initial or neutral, such as that shown in  FIG. 22 . In this initial position, the blocking members  27   a ,  27   b  of each shutter member  29   a  and  29   b , block each of the respective openings  32   a  and  32   b . In one embodiment, in the initial position the shutter members  29   a ,  29   b  are substantially symmetrically located about centerline C of the registration member  34 . The resilient members  10   a ,  10   b  may be configured such that the forces exerted on their respective shutter members  29   a ,  29   b  are substantially equal so that the resultant force exerted by the resilient members  10   a ,  10   b  place the shutter members as shown in  FIG. 22  when the springs are at equilibrium. In another embodiment the recesses  26   b ,  26   c  along with the resilient members may serve to position the shutter members  29   a ,  29   b  in the initial position through interaction between the longitudinal orbits  26  and the recesses  26   b ,  26   c.    
     Referring to  FIGS. 11 and 12 , an example where an attempt is made to insert a single plug blade  50   a  into receptacle  43  of the protective shutter assembly  1  is shown. As the plug  50   a  is inserted into receptacle  43  through the upper cover  46 ,  246 , for example, the plug element  50   a  encounters ramp  24   a . The ramp member  24   a  is configured such that the force of the plug element  50   a  exerted on the surface of the ramp  24   a  in the direction of arrow F causes the shutter member  29   a  to move in the direction B shown in  FIG. 11 . The movement of shutter member  29   a  in the direction B causes shutter member  29   a  to compress resilient member  10   b . As shutter member  29   a  moves in the direction B, it comes into contact with, or is substantially urged against shutter member  29   b , which is, at this point, in a stationary position. In one embodiment width W (See  FIG. 20 ) of each ramp member  24   a ,  24   b  is suitably sized so that when shutter  29   a  is moved in the direction of B to is most extreme position the backs  24   e  (See  FIG. 20 ) of the ramp members substantially contact each other. As shutter  29   a  moves in the direction B, resilient member  10   a  extends and exerts a force on shutter member  29   b  in the direction of B. Referring to  FIG. 23 , an example of the interaction of members  29   a  and  29   b  is illustrated. As shown in the figure, members  29   a  and  29   b  contact each other at points  229   a  and  229   b.    
     In one embodiment, the movement of shutter member  29   b  in the direction B causes shutter blocking member  27   b  to block the polarity receptacle opening  32   a  while the substantial contact between the backs  24   e  of the ramp members  24   a ,  24   b  prevents movement of the blocking member  27   b  in a direction opposite that of direction B. 
     As shown in  FIG. 11 , blocking member  27   b  prevents plug element  50   a  from progressing any further into the receptacle  43  by blocking opening  32   a . Receptacle  44  also is blocked by the combination of ramp  24   b  and shutter blocking member  27   a , which cover or block opening  32   b . This effectively avoids or prevents the danger of foreign objects being inserted in a receptacle contact opening and making an electrical connection, which can cause electric shock hazard. Although this example has been described with the use of plug element  50   a , it will be understood that the blocking mechanism of the protective shutter assembly of the disclosed embodiments will react similarly to insertion of any suitable object into only one of the two openings  43 ,  44 . 
     The configuration of the shutter members  29   a ,  29   b  to substantially contact each other in the manner described above prevents the sequential insertion of objects into the openings  43 ,  44 . It is only when two suitable elements, such as elements  50   a  and  50   b , are substantially simultaneously inserted into the openings  43 ,  44 , that the respective shutter members  29   a ,  29   b  will move sufficiently to allow the elements  50   a ,  50   b  to pass by blocking members  27   b ,  27   a  and into the corresponding polarity receptacle opening  32   a ,  32   b . It is noted that the width W of the ramp members  24   a ,  24   b  is configured to allow a predetermined amount of travel in opposite directions so that both ramp members  24   a ,  24   b  and both blocking members  27   a ,  27   b  are clear of the openings  32   a ,  32   b ,  43 ,  44  when objects are substantially simultaneously inserted into both opening  43 ,  44  as shown in, for example  FIG. 9 . 
     Referring to  FIGS. 9 and 10 , when the receptacle is in use, plug blades  50   a  and  50   b  are inserted into the neutral receptacle opening  43 ,  243  and the hot receptacle opening  44 ,  244  respectively through the cover  46 ,  246 . The neutral receptacle opening  43 ,  243  and hot receptacle opening  44 ,  244  of the cover  46 ,  246  substantially align to the respective polarity receptacle openings  32   a ,  32   b  of the registration assembly  34 .  FIGS. 9 and 10  illustrate an example where two plug elements  50   a ,  50   b  have been substantially simultaneously inserted into corresponding receptacle openings  44 ,  43 . As shown in  FIG. 9 , as plug blades  50   a ,  50   b  are being substantially simultaneously inserted into the respective receptacle openings  43  and  44 , each plug blade  50   a ,  50   b  first arrives at a respective shutter ramp  24   a ,  24   b . Continued insertion of the plug blades  50   a ,  50   b  will cause each shutter ramp member  24   a ,  24   b  to move or slide in respective opposing directions A 1 , A 2  within the registration member  34 . This moves the shutter members  29   a  and  29   b  in opposing directions far enough to allow plug blade  50   a ,  50   b  to extend through the polarity receptacle opening  32   a ,  32   b  on the registration assembly  34 . Movement of the shutter members  29   a ,  29   b  also causes the compression of resilient members  10   a  and  10   b . The shutter blocking members  27   a  and  27   b  also move in opposing respective directions A 1 , A 2 . This opens access to polarity receptacle openings  32   a  and  32   b  as can be seen in  FIG. 9 . Each plug element  50   a  and  50   b  can pass through the respective polarity opening  32   a ,  32   b  and enable an electrical connection with one of, for example, a hot or neutral power receptacle of connector. It is noted that when the plug blades  50   a ,  50   b  are pulled out, the shutters  29   a ,  29   b  return to the initial, closed position, from for example forces exerted on the respective shutter members  29   a ,  29   b  by the resilient members  10   a ,  10   b . By returning the shutter members  29   a ,  29   b  to the initial position, the neutral receptacle opening  43 ,  243  and the hot receptacle opening  44 ,  244  are blocked again. 
     In one embodiment, the receptacle can include two sets of six receptacle contact openings configured to accommodate two sets of six plug blades with a predetermined plug blade geometry. A plurality of receptacle contacts is disposed in the device, each of the plurality of receptacle contacts being in communication with a corresponding one of the two set of receptacle openings. The protective shutter assembly is disposed in the cover assembly, and the registration structure in the cover will position and align the protective shutter assembly within the cover assembly. Ultrasonic welding and four installation cover latches can be to used complete the device, to provide a firm product structure. 
     The aspects of the disclosed embodiments provide an electrical receptacle with a protective shutter where the shutter sub-assembly inside one receptacle opening will open only when the other receptacle opening is inserted, substantially simultaneously, with a plug blade having a predetermined plug blade geometry, and then with the push of the spring, the shutter sub-assembly will finally turn to open position. This approach effectively prevents the hidden danger of foreign objects insertion into one of the receptacle contact opening which will cause electric shock hazard. 
     It should be understood that the foregoing description is only illustrative of the embodiments. Various alternatives and modifications can be devised by those skilled in the art without departing from the embodiments. Accordingly, the present embodiments are intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.