Mating electrical safety plug and receptacle

A mating electrical safety plug and receptacle. The plug includes a set of non-conductive tubular prongs, each of which shrouds a conductive element. The ends of each prong are open to receive a corresponding central post of the receptacle. The plug may include a ground prong. The receptacle is provided with a set of openings, each opening adapted to receive a corresponding prong. Each opening has a central post concentrically disposed, thus producing an annular cavity for the receipt of a tubular prong. Each central post includes a recess having a conductive element disposed therein. The receptacle may also be provided with a ground opening to accommodate a plug with a ground prong. The conductive element recessed within each central post engages with a respective conductive element shrouded by a corresponding prong. These mating conductive elements engage only when the plug is fully connected. The shrouding of the conductive element in each of the prongs essentially eliminates the risk of an individual encountering an electrical shock resulting from a partially disconnected plug. The indirect accessibility of the conductive element recessed within each central post further lessens the risk of electrical shock as a result of inserting a foreign object (other than the plug) into the receptacle.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a mating electrical safety plug and 
receptacle and more particularly, to an electrical plug and receptacle 
having a configuration which reduces the risk of accidental shock. 
2. Description of the Prior Art 
Contemporary conventional homes are supplied with numerous electrical 
receptacles. Electrical codes specify receptacle location requirements, 
that is to say how far a receptacle should be located from an opening in a 
wall as well as the spaced apart relationship between receptacles. Current 
standards typically require a receptacle be located within six feet of 
both sides of a doorway, a fireplace, or even a bay window. Standards also 
dictate a spaced apart relationship between receptacles. This spacing is 
generally less than or equal to twelve feet apart. Unlike earlier built 
homes, outlets are no longer sparsely distributed throughout a house but 
are distributed in such a manner so as to permit a homeowner to supply 
current to an appliance from virtually any point in the home without the 
aid of an extension cord. With this convenient distribution of 
receptacles, not only are receptacles becoming more accessible to children 
but appliances are being relocated more often, increasing the frequency 
with which a plug is connected and disconnected from a receptacle. As a 
result, adults and children alike are exposed to greater risk of hazardous 
electrical shock. A common occurrence of electrical shock results from 
contact with the partially exposed plug prongs of a partially disconnected 
plug. An insulated plug prong would reduce the risk of this dangerous 
exposure to electricity. 
U.S. Pat. No. 3,631,320 issued Dec. 28, 1971 to William F. Eckert discloses 
a conventional type two prong plug having accordion-like insulated prong 
sleeves which contract and expand when the plug is connected and 
disconnected, respectively. This shields the plug prongs and thus, reduces 
the risk of accidental shock when the plug is partially withdrawn from the 
receptacle. This sleeve, however, is fabricated of a pliable material 
which is expansible and collapsible and is, therefore, substantially 
susceptible to splitting or cracking over a prolonged period of use, thus 
may eventually allow current to leak through. 
U.S. Pat. No. 4,674,807 issued Jun. 23, 1987 to William C. Boteler et al. 
describes an electrical non-conductive outer housing and connector members 
recessed in one end of the housing. A male plug of this type would require 
a mating connector having a generally cylindrical non-conductive body. A 
mating connector of this type would protrude from a wall plate to a 
significant extent, unlike conventional receptacles which are 
substantially flush with a wall plate. The protrusion of a receptacle of 
this variety may be considered excessive and unsightly. Moreover, there 
exists no measure to prevent a foreign object (other than the mating plug) 
from being inserted into the receptacle and from engaging with the 
conductive elements within the receptacle, thus offering exposure to 
electrical shock. 
A plug having a set of prongs fabricated of an non-conductive material, 
each prong facilitating as a shroud to conceal a conductive element, and a 
mating receptacle being configured so as to reduce the accessibility of 
the conductive elements by foreign objects (other than the mating plug) 
would reduce the risk of electrical shock. 
None of the above inventions and patents, taken either singly or in 
combination, is seen to describe the instant invention as claimed. 
SUMMARY OF THE INVENTION 
The present invention relates to a mating electrical safety plug and 
receptacle. The plug includes a set of non-conductive tubular prongs, each 
of which shrouds a conductive element. The ends of the prongs are open to 
receive a central post of the receptacle. The plug may include a ground 
prong. The ground prong is comprised of an non-conductive tubular member 
having an end enclosed by an electrically conductive tip. The receptacle 
is provided with a set of openings, each opening adapted to receive a 
corresponding prong. Each opening is provided with an aforementioned 
central post which is concentrically disposed therein to produce an 
annular cavity to receive a tubular prong. Each central post includes a 
recess having a conductive element disposed therein. The receptacle may be 
provided with a ground opening which does not have a central post disposed 
therein. This ground opening is provided for the receipt of the ground 
prong. A conductive element is disposed within the ground opening which 
make contact with the conductive tip of the ground prong when the plug is 
connected to the receptacle. Moreover, when the plug is connected to the 
receptacle, the conductive element recessed within each central post 
engages with a respective conductive element shrouded by a corresponding 
prong. These mating conductive elements engage only when the plug is fully 
connected. The shrouding of the conductive element in each of the prongs 
essentially eliminates the risk of an individual encountering an 
electrical shock even when the plug is partially connected or disconnected 
from the receptacle. The unique configuration of the receptacle, that is, 
the indirect accessibility of the conductive element recessed within each 
central post reduces the risk of electrical shock as a result of inserting 
a foreign object (other than the plug) into the receptacle. 
Accordingly, it is a principal object of the invention to provide a mating 
electrical safety plug and receptacle which reduces the risk of hazardous 
electrical shock. 
It is another object of the invention to provide a plug which has a set of 
prongs, each prong being fabricated of an nonconductive material which 
facilitates as an insulating shroud to conceal a conductive element. 
It is another object of the invention to provide a plug which is adaptable 
for use on virtually any appliance. 
It is another object of the invention to provide a plug which is may be 
employed in either single phase or multi-phase applications. 
It is another object of the invention to provide a receptacle having a 
configuration which does not permit foreign objects (other than the mating 
plug) to have immediate access to the conductive elements disposed 
therein. 
It is another object of the invention to provide a mating electrical plug 
and receptacle which employs a unique conductor coupling configuration 
which substantially eliminates the risk of electrical shock occurring f 
rom a partially connected or disconnected plug. 
It is an object of the invention to provide improved elements and 
arrangements thereof in an apparatus for the purposes described which is 
inexpensive, dependable and fully effective in accomplishing its intended 
purposes. 
These and other objects of the present invention will become readily 
apparent upon further review of the following specification and drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention, as shown in FIG. 1, is a mating electrical safety 
plug 10 and receptacle 30. The receptacle 30 is shown surface mounted 
within a wall 50 and partially covered with a conventional wall plate 70. 
Referring to FIGS. 2-5, the plug 10 it comprised of a main body portion 12 
having a set of non-conductive tubular prongs 14 projecting from a face 
thereof . Each prong facilitates as a shield to shroud a conductive 
element 16. The ends of the prongs 14 are each provided with an opening 18 
to provide access to the conductive element 16. A non-conductive tubular 
ground prong 20 may be provided for plugs 10 which mate with ground 
receptacles 30. The end of the ground prong 20 is enclosed by a conductive 
tip 22. The conductive elements 16 and the conductive tip 22 are each 
joined to a respective conductor 24. The conductors 24 each originate from 
a multi-conductor cable or cord 26 which enters the through the rear end 
of the plug 10. The plug 10 may be molded in a conventional manner of a 
hard rubber material. Though the plug 10 is shown with a ground prong 20, 
the invention is not limited to applications of this type. That is, the 
plug 10 is not limited to the configuration shown, but may be configured 
without a ground prong 20 as well. 
Now, referring to FIGS. 6-9, the receptacle 30 is shown in a duplex 
configuration. The receptacle 30 is not limited to this configuration but 
may be configured as a single receptacle, such as for use as a flush mount 
floor receptacle. The receptacle 30 is comprised of a main body portion 32 
having a set of non-conductive central posts 34, each post 34 being 
concentrically disposed within an opening 36, thus forming an annular 
cavity 38 between the central post 34 and the inner peripheral walls which 
define the opening 36. Each central post 34 includes a recess 40 having a 
conductive element 42 disposed therein. Similar to the foregoing prongs, 
each central post 34 also facilitates as a shield to shroud a conductive 
element 42. The conductive element 42 within each central post 34 is only 
accessible through the respective recess 40. A ground opening 44 may be 
provided to accommodate plugs 10 with ground prongs 20. To the rear of the 
ground opening 44 is disposed a conductive ground element 46. The 
conductive elements 42 and the conductive ground elements 46 are each 
connected to the conductive wiring 48 of the electrical system. The 
conductive wiring 48 originates from a service panel (not shown) and 
distributes power throughout the electrical system. The receptacle 30 may 
be molded in a conventional manner of a ceramic material. Though the 
receptacle 30 is shown with a ground opening 44 and though the receptacle 
30 is configured to be employed in single phase circuits, the invention is 
not limited to applications of this type. The receptacle 30 is not limited 
to the configuration shown, but may be configured to be employed in 
multi-phase circuits and may be configured without a ground opening 44 as 
well. 
FIG. 10 shows the plug 10 connected to the receptacle 30. The opening 18 
(see FIGS. 2-4) in the end of each prong 14 provides a passage for a 
mating central post 34. Likewise, each annular cavity 38 (see FIGS. 6-8) 
is provided to receive a mating prong 14. Note, due to the orientation of 
the conductive elements 16,42, polarization is maintained constant for 
every appliance (not shown) throughout a circuit. When the plug 10 is 
fully connected to the receptacle 30, each conductive element 16 of the 
plug 10 enters a respective recess 40 of the receptacle 30 to engage with 
a corresponding conductive element 42 of the receptacle 30. Because of the 
shielding effect of each prong 14, the conductive elements 16 of the plug 
10 are not exposed when the plug 10 is partially connected or disconnected 
from the receptacle 30. Moreover, by positioning the conductive elements 
42 of the receptacle 30 within a recess 40, the conductive elements 42 of 
the receptacle are indirectly accessible as well. Thus, the risk of 
hazardous electrical shock is virtually eliminated. 
It is to be understood that the present invention is not limited to the 
sole embodiment described above, but encompasses any and all embodiments 
within the scope of the following claims.