Note: Descriptions are shown in the official language in which they were submitted.
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= TAMPER-RESISTANT ELECTRICAL WIRING DEVICE SYSTEM
=
=
=
FIF.LD OF THE INVENTION
1. Technical Field
= 100021 The present invention relates to electrical receptacles,
and, more particularly, to a
tamper-resistant electrical wiring device system.
2. Background of the Invention
= 00031 Electrical power transmitted from a source to a point of use
through an electrical,
distribution system within a home or a commercial building for equipment and
operations is a
beneficial service. Conventional electrical receptacles within such a
distribution system include -
a pair of slots or apertures aligned with co,ntacts, wherein prongs of an
electric plug may be
insetted in the pair of apertures to directly engage contacts within .the
receptacle in an effort to
facilitate a desired electrical. connection. Since a large percentage of these
receptacles are used
in residential buildings and are located near the floor, a young child or
infant, for example, may
CA 02624409 2014-09-03
insert a small object into either one of the apertures which potentially may
result in electrical
shock. More particularly, a burn or shock may result when a child's wet mouth
enables electrical
contact, wherein a path exists from the hot contact through the child to
ground, establishing a
ground fault.
[0004] Besides a child's fingers and mouth, children may insert into
receptacles a wide
variety of objects made of conductive material including but not limited to a
metal articles. Most
objects may be everyday household and easily accessible items such as, paper
clips, pens wire
tools, hairpins, safety pins, keys, forks, knives, screws, nails, tweezers and
coins. Since some of
these objects may be perceived by parents as safe, parents tend not to
restrict access to many of
these objects.
[0005] Both scenarios present circumstances to be avoided, where possible.
As such, the
issue of human safety and avoiding hazards has always been considered by the
owner of the
instant application in developing new products. Further, in an effort to
eliminate the foregoing,
the National Electrical Code (NEC) now requires tamper-proof electrical
receptacles in pediatric
environments since electrical shocks often occur in these types of
environments. Research
studies have shown that many of these incidents happen around meal time, when
parents are
occupied in the kitchen and children are not well supervised. A National
Electrical
Manufacturer's Association (NEMA) task force has concluded that every
residential building
should be required to have tamper-resistant electrical receptacles and ground
fault circuit
interrupters (GFCI) designed within the electrical distribution system
throughout the home.
[0006] Presently available circuit interrupter devices, such as the device
described in
commonly owned U.S. Pat. No. 4,595,894,
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use a trip mechanism to mechanically break an electrical connection between
one or
more input and output conductors. Such devices are resettable after they are
tripped after the
detection of a ground fault. The ground fault circuit interrupter, however,
only disconnects the
circuit after electrical contact is made with a conductor. Thus, without a
tamper resistant
electrical receptacle, a person may still experience an initial temporary
shock.
100071 Numerous child-proof devices have been proposed or are commercially
available
which are directed to preventing a child from touching the apertures in a
receptacle assembly or
preventing a child from inserting or removing an electrical plug in or from
the apertures. No
such device, however, has achieved wide acceptance; therefore, the
aforementioned condition
remains today. This is primarily due to ineffectiveness of each device,
expense, and the lack of
ease of use. Foremost among these drawbacks is one of expense. That is, there
are conventional
devices that may be applied to various receptacles with safety features.
However, the added
expense required to manufacture such receptacles outweighs the safety
advantage.
[00081 Prior patents featuring safety electric receptacles have generally
comprised
attachments for the face plate of an electric receptacle featuring rotstable
snap-on or sliding
covers for the electric socket opening, such as disclosed by U.S. Pat. Nos.
3,639,886 and
3,656,083 in which the face plate attachments are manually moved for insertion
and removal of
the plug. These attachments, such as plastic receptacle caps, are generally
designed to include
plastic plates having a pair of wall receptacle aperture engaging blades.
These plastic receptacle
caps, however, are unreliable and inefficient. Research in 1997 by the Temple
University
Biokinetics Laboratory in Philadelphia showed that 47% of the 4 year olds in a
test group were
able to remove one brand of receptacle caps. For another similar embodiment of
a receptacle
cap, 100% of the children within the age group of 2 to 4 years of age were
able to remove the
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receptacle cap in many cases in less than 10 seconds. Other disadvantages of
plastic receptacle
caps include but are not limited to the forgetfulness of adults to reinsert
the caps. In addition,
receptacles are susceptible to being exposed to a child who may pull a lamp
cord, leaving the
receptacle unprotected. Furthermore, constant pressure from the plastic blades
on the receptacle
contacts increase contact distortion, increasing the risk of loose contacts
and/or creating poor
contacts, resulting in plugs falling out of the receptacle. Moreover, many of
the plastic
receptacle caps may create choking hazards, since they may fail to pass a
choke hazard test
described in a UL standard.
[0009] Other patents, such as U.S. Pat. Nos. 2,552,061 and 2,610,999
feature overlying
slotted slidable plates which must be manually moved to mate the overlying
plate slots with the
electric receptacle slots or openings for insertion and removal of the plug.
Sliding shutter plates
offer a better level of protection than receptacle caps. However, none of the
sliding shutter plates
that are on the market are UL listed. This is primarily due to the fact that
they add extra layers of
material between the plug prongs and the receptacle contacts which reduces the
surface of
contact between plug prongs and contacts, causing potential heat rise or
arcing which may also
be hazardous. Another disadvantage of a manually movable face plate is that a
small child, by
observation, may learn to expose the electric receptacle.
[0010] Thus, a need exists for an simple, effective, efficient, low-cost
electrical
receptacle that is tamper-proof and does not need continuous manual
adjustment. This device
must prevent electric shock when one inserts a conductive instrumentality
other than the plug of
an appliance, while still permitting full surface contact between the plug
prongs and contacts and
frequent insertion and removal of prongs.
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[0011] The present invention is directed to overcoming, or at least
reducing the effects of
one or more of the problems set forth above.
SUMMARY OF THE INVENTION
[0012] To address the above-discussed deficiencies of child-proof devices
for electrical
receptacles, the present invention teaches a tamper resistant electrical
receptacle that has a
simple, effective, efficient, low-cost design that does not need continuous
manual adjustment.
This device prevents electric shock when one inserts an object into one
aperture in the cover,
while still permitting the frequent insertion and removal of plugs to an
electrical appliance.
[0013] Specifically, a tamper resistant electrical receptacle in accordance
with the present
invention includes a base assembly that connects to a cover assembly, wherein
the cover
assembly having at least one pair of cover apertures, includes a slider
positioned in a first
position to block entry into the cover assembly when an object is inserted
into only one cover
aperture (the typical scenario for children probing electrical receptacles).
When, however, a pair
of prongs are inserted into the electrical receptacle, the slider shifts out
of the way into a second
position that enables the pair of prongs to engage the receptacle terminals
located in the base
assembly. Access to the receptacle terminals is thus prevented significantly
reducing the
likelihood of electric shock due to contact with these terminals.
[0014] A first embodiment of the tamper-resistant electrical receptacle for
electrical
connection between an appliance having a pair of prongs and a power
distribution system
includes a base assembly attached to a cover assembly. The cover assembly
includes a cover
having at least one pair of apertures for at least one pair of prongs of an
external electrical plug
to be inserted therethrough. The apertures in the cover assembly align with
receptacle terminals
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in the base assembly. The cover assembly further includes at least one slider
that rests in the
cover behind one pair of the apertures. The slider is held in a first position
wherein the slider
covers both apertures of the cover such that an object is blocked from
entering into either of the
pair of apertures in the cover and, thereby, prevents access to the receptacle
terminals. The slider
is restricted to the first position when an object probes only one aperture in
the cover. This first
position is maintained until a pair of prongs are inserted into the pair of
apertures causing the
slider to slide into a second position allowing the pair of prongs to pass
through the pair of
apertures in the cover and enabling each prong to engage a respective one of
the receptacle
terminals. In this second position, the width of the slider is selected such
that when the slider
moves into this position the aperture covers are no longer covered and blocked
by the slider.
Thus, the receptacle terminals are fully accessible to the pair of prongs in
the second position.
After the pair of prongs are removed from the receptacle terminals, the slider
automatically
retracts to the first position where access to the receptacle terminals is
blocked.
100151
Another embodiment of the tamper-resistant electrical receptacle for
electrical
connection between an appliance and a power distribution system includes a
base assembly
attached to a cover assembly, wherein the apertures in the cover assembly
align with the
receptacle terminals in the base assembly. The cover assembly includes a cover
having at least
one pair of apertures for at least one pair of prongs of an external
electrical plug to be inserted
therethrough. The cover assembly further includes at least one platform sub-
assembly, wherein
each platform sub-assembly rests in the cover behind one pair of the
apertures. The platform
sub-assembly includes a slider, a platform, and a leaf spring. The slider
rests in the platform and
is held into position by a leaf spring that is in juxtaposition with the
slider.
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[0016] The leaf spring is used to load the slider in a first
position where the slider covers
both apertures in the cover such that an object is blocked from entrance into
either of the pair of
apertures in the cover. The leaf spring, the platform and the cover confine
the slider in the first
position when an object probes only one aperture in the cover. This first
position is maintained
until the pair of prongs are inserted into the pair of apertures causing the
slider to slide into a
second position allowing the pair of prongs to pass through the pair of
apertures in the cover so
that each prong engages a respective one of the receptacle terminals. In this
second position, the
slider is designed to be just wide enough to allow the receptacle prongs
access to the pair of
prongs. After the pair of prongs are removed from the receptacle terminals,
the leaf spring
automatically retracts the slider to the first position, in which access to
the receptacle terminals is
blocked.
[0017] Another embodiment of the tamper-resistant electrical
receptacle of the present
invention includes a base assembly attached to a cover assembly, wherein the
apertures in the
cover assembly align with the receptacle terminals in the base assembly. The
cover assembly
includes a cover having at least one pair of apertures for at least one pair
of prongs of an external
electrical plug to be inserted therethrough. The cover assembly further
includes at least one
platform sub-assembly, wherein each platform sub-assembly rests in the cover
behind one pair of
the apertures. The platform sub-assembly includes a slider, a platform, and a
leaf spring. The
slider having a slider aperture rests in the platform and is held in position
by the leaf spring that
is positioned juxtaposed to the slider for loading the slider into a
misaligned position where the
slider aperture is misaligned with respect to the aperture in the cover such
that an object is
blocked from entering into either of the apertures in the cover.
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100181 The leaf spring, the platform and the cover confine the slider in
the misaligned
position when an object probes only one aperture in the cover. This misaligned
position is
maintained until a pair of prongs are inserted into the pair of apertures,
causing the slider to slide
into an aligned position wherein the slider aperture aligns with one of the
pair of apertures of the
cover, thereby enabling a first prong to slip through both the cover aperture
and the slider
aperture, and a second prong to slip through the other cover aperture and
bypassing the slider. In
this alignment position, the slider is designed to be just wide enough so that
the when the slider
aperture aligns with one aperture in the cover, the slider does not cover the
other respective
aperture. Upon removal of the pair of prongs from the receptacle terminals,
the leaf spring urges
the slider back into the misaligned position.
100191 Another embodiment of the tamper-resistant electrical receptacle of
the present
invention includes a base assembly attached to a cover assembly, wherein the
apertures in the
cover assembly align with the receptacle terminals in the base assembly. The
cover assembly
includes a cover having at least one pair of apertures for at least one pair
of prongs of an external
electrical plug to be inserted therethrough. Moreover, the cover includes an
upper rib formed on
the interior surface of the cover. The cover assembly further includes at
least one platform sub-
assembly, wherein each platform sub-assembly rests in the cover behind one
pair of the
apertures. The platform sub-assembly includes a slider, a platform, and a leaf
spring. The slider
having a slider aperture rests in the platform and is held in position by a
leaf spring that is
positioned juxtaposed to the slider for loading the slider into a misaligned
position where the
slider aperture is misaligned with respect to the aperture in the cover such
that an object is
blocked from entrance into either of the pair of apertures in the cover.
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[0020] The platform includes a lower rib formed on its interior surface.
When an object
is inserted into only one first aperture of the cover, the upper rib formed on
the interior surface of
the cover blocks movement of the slider from transitioning from the misaligned
position into an
align position wherein the receptacle terminals are left open and accessible.
In the alternative
when an object is inserted into only one second aperture of the cover, the
lower rib formed on the
interior surface of the platform blocks movement of the slider from
transitioning from the
misaligned position into an align position wherein the receptacle terminals
are left open and
accessible. Thereby the upper rib of the cover and the lower rib of the
platform confine the
slider to the misaligned position when an object probes only one aperture in
the cover. This
misaligned position is maintained until the pair of prongs are inserted into
the pair of apertures
causing the slider to slide into an aligned position where the slider aperture
aligns with one of the
pair of apertures in the cover enabling a first prong to slip through both the
aperture and the
slider aperture, and a second prong to slip through a corresponding one of the
pair of apertures
bypassing the slider.
[0021] In the alignment position, the slider is designed to be just wide
enough so that
when the slider aperture aligns with one aperture in the cover, the slider
does not cover the other
aperture. After the pair of prongs are removed from the receptacle terminals,
the leaf spring
moves the slider back into the misaligned position.
[0022] Advantages of this design include but are not limited to, a tamper-
resistant
electrical receptacle that is permanent in that once the unit is installed it
offers protection for the
life of the building structure. The tamper-resistant electrical receptacle in
accordance with the
present invention is reliable since this receptacle is not manually removable.
In addition, a user
need not be concerned about losing the associated part that makes the
electrical receptacle
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tamper-resistant. Further, a user needs to be concerned with breaking the
tamper-resistant
electrical receptacle because the platform sub-assembly is secured behind the
cover of the
electrical receptacle. Moreover, the tamper-resistant electrical receptacle
provides automatic
protection even when a plug is removed because the spring loaded slider
retracts back to the
closed position for immediate protection.
[0023] These and other features and advantages of the present invention
will be
understood upon consideration of the following detailed description of the
invention and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] For a more complete understanding of the present invention and the
advantages
thereof, reference is now made to the following description taken in
conjunction with the
accompanying drawings in which like reference numbers indicate like features
and wherein:
[0025] FIG. 1 shows an exploded view of a 15 ampere embodiment of the
tamper
resistant assembly in accordance with the present invention;
[0026] FIG. 2 illustrates an exploded view of a 15 ampere embodiment of
the platforrn
sub-assembly in accordance with the present invention;
[0027] FIGS. 3, 7a, and 7b display the platform sub-assembly completely
assembled in
accordance with the present invention;
[0028] FIG. 4 shows the cover assembly in accordance with the present
invention;
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[0029] FIGS. 5a and 5b display two views of the leaf spring placement by a
suitable tool
into the platform in accordance with the present invention;
100301 FIGS. 6a and 6b illustrate the placement of the slider into the
platform, next to the
leaf spring;
[0031] FIG. 8 illustrates an exploded view of the base and cover assembly
in accordance
with the present invention;
[0032] FIG. 9 displays the tamper resistant assembly in accordance with the
present
invention;
[0033] FIGS. 10a and 10b show the tamper resistant assembly when a pair of
prongs
from an electrical appliance are inserted into the pair of apertures in the
cover at two respective
depths;
[0034] FIG. lla and 1 lb displays the tamper resistant assembly when a
single object is
used to probe apertures, 39 and 41, in the cover, respectively;
[0035] FIG. 12 displays the platform in accordance with one embodiment of
the present
invention;
[0036] FIG. 13 shows the leaf spring in accordance with one embodiment of
the present
invention;
[0037] FIGS. 14a and 14b illustrate the front and back side of the slider
in accordance
with one embodiment of the present invention;
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[0038] FIG. 15 shows an exploded view of the 20 ampere embodiment of the
tamper
resistant assembly in accordance with the present invention;
[0039] FIG. 16a illustrates an exploded view of a 20 ampere embodiment of
the platform
sub-assembly in accordance with the present invention;
[0040] FIGS. 16b, 20a and 20b display the platform sub-assembly completely
assembled
in accordance with the present invention;
[0041] FIG. 17 shows the cover assembly in accordance with the present
invention;
[0042] FIGS. 18a and 18b display two views of the leaf spring placement by
a suitable
tool into the platform in accordance with the present invention;
[0043] FIGS. 19a and 19b illustrate the placement of the slider into the
platform, next to
the leaf spring;
100441 FIGS. 21a and 21b show the tamper resistant assembly prior to and
after the
insertion of a pair of prongs from an electrical appliance into the pair of
apertures in the cover;
[0045] FIGS. 22a and 22b display another view of the tamper resistant
assembly prior to
and after the insertion of a pair of prongs from an electrical appliance into
the pair of apertures in
the cover;
[0046] FIGS. 23a and 23b illustrate the front and back side of the leaf
spring in
accordance with one embodiment of the present invention;
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[0047] FIGS. 24a and 24b show the tamper resistant assembly when a pair of
prongs
from an electrical appliance are inserted into the pair of apertures in the
cover at two respective
depths;
[0048] FIGS. 25a and 25b display the tamper resistant assembly when a
single object is
used to probe the apertures; 112 and 114: in the cover, respectively;
[0049] FIG. 26 illustrates an exploded view of the base and cover assembly
in
accordance with the present invention;
[0050] FIG. 27 displays the tamper resistant assembly in accordance with
the present
invention;
[0051] FIGS. 28a and 28b depict a tamper resistant assembly in accordance
with the
present invention prior to and after insertion of a pair of prongs from an
electrical appliance;
[0052] FIGS. 29a and 29b depict a tamper resistant assembly in accordance
with the
present invention when a single object is used to probe apertures in the
assembly;
[0053] FIG. 30 is a perspective view of a platform subassembly according to
another
embodiment of the present disclosure, for use with a 15 Amp receptacle;
[0054] FIG. 31 is an exploded, perspective view of the platform subassembly
of FIG. 30;
[0055] FIG. 32 is a perspective view of a slider of the platform
subassembly of FIGS. 30
and 31;
[0056] FIG. 33 is a top, plan view of the slider of FIG. 32;
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[0057] FIG. 34 is a right, side elevational view of the slider of FIG. 32;
[0058] FIG. 35 is a left, side elevational view of the slider of FIG. 32;
[0059] FIG. 36 is a front, elevational view of the slider of FIG. 32;
[0060] FIG. 37 is a rear, elevational view of the slider of FIG. 32;
[0061] FIG. 38 is a bottom, plan view of the slider of FIG. 32;
[0062] FIG. 39 is a perspective view of a platform of the platform
subassembly of FIGS.
30 and 31;
[0063] FIG. 40 is atop, plan view of the platform of FIG. 39;
[0064] FIGS. 41A and 41B show the platform subassembly of FIGS. 30-40, when
a pair
of prongs from an electrical appliance are inserted into the pair of apertures
in the cover at a
common depth;
[0065] FIGS. 42A and 42B show the platform subassembly of FIGS. 30-40, when
a
single object is used to probe an aperture of the cover;
[0066] FIG. 42C shows the platform subassembly of FIGS. 30-40, when a
single object is
used to probe an aperture of the cover while being introduced at an angle;
[0067] FIG. 43 is a perspective view, with parts separated, of a 20 Amp
receptacle
including a platform subassembly according to another embodiment of the
present disclosure;
[0068] FIG. 44 is a perspective view, with parts separated, of the platform
subassembly
of FIG. 43;
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100691 FIG. 45 is a top perspective view of a slider of the platform
subassembly of FIGS.
43 and 44;
[0070] FIG. 46 is a bottom perspective view of the slider of FIG. 45;
[0071] FIG. 47 is a perspective view of a platform of the platform
subassembly of FIGS.
43 and 44;
[0072] FIG. 48 is a perspective view of a biasing member of the platform
subassembly of
FIGS. 43 and 44;
[0073] FIGS. 49A and 49B show the platform subassembly of FIGS. 43-48, when
a pair
of prongs from an electrical appliance are inserted into the pair of apertures
in the cover at a
common depth; and
[0074] FIGS. 50A and 50B show the platform subassembly of FIGS. 43-48, when
a
single object is used to probe an aperture of the cover.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0075] The present invention will now be described more fully hereinafter
with reference
to the accompanying drawings, in which embodiments of the invention are shown.
This
invention may, however, be embodied in many different forms and should not be
construed as
limited to the embodiments set forth herein. Rather, these embodiments are
provided so that this
disclosure will be thorough and complete, and will fully convey the scope of
the invention to
those skilled in the art.
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100761 Specifically, a tamper resistant electrical receptacle in
accordance with the present
invention includes a base assembly that connects to a cover assembly, wherein
the cover
assembly includes a platform sub-assembly having a platform, a slider, and a
leaf spring. The
slider positioned is placed in a first position to block entry into the cover
assembly when an
object is inserted into only one cover aperture which is the typical scenario
for children probing
electrical receptacles. When, however, a pair of prongs are inserted into the
electrical receptacle,
the slider shifts out of the way into a second position that enables the pair
of prongs to engage
receptacle terminals located in the base assembly. Thereby, this electrical
receptacle effectively
prevents electric shock
[0077] FIGS. 1-14b illustrate a first embodiment of the tamper resistant
receptacle 40 in
accordance with the present invention. Specifically, FIG. 1 shows an exploded
view of the
tamper resistant electrical receptacle 40 in accordance with the present
invention. The receptacle
40, as shown in FIG. 1, is a duplex three-prong electrical receptacle for
handling 15 amp current
applications. However, it should be understood that the receptacle can be a
two or three-prong
electrical receptacle or a receptacle other than that of a duplex receptacle.
[0078] As shown in FIG. 1, cover 20 sits on top of a pair of platform sub-
assemblies
including platform 16, leaf spring 14 and slider 12. Mounting screws 46 mount
strap 48 onto the
base 56 using retaining washers 50. Ground contacts 42 connect onto strap 48.
Finally, contacts
52 connect to the base 56 using terminal screws 54 to form the receptacle
terminals in base 56.
[0079] Specifically, referring to FIG. 2, an exploded view of the platform
sub-assembly
includes a slider 12, a leaf spring 14, and a platform 16. Slider 12 includes
at least one rib 13. It
is noted that rib 13 may be one or more projections as shown in FIGS. 2 and
14b. A slider
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aperture 15 is included in slider 12 to enable one prong to be inserted
through to make contact
with the receptacle terminals in the base of the tamper resistant receptacle
40. The cover 20 may
include at least one pair of apertures. As such, slider aperture 15 must align
with at least one of
the apertures from an aperture pair of cover 20 to enable a prong to pass
through the slider
aperture 15 to a receptacle terminal which shall be explained in further
detail.
[0080] Leaf spring 14 is mounted in pocket 17 of platform 16 as is shown
in the series of
FIGS. 5a, 5b, 6a, 6b, 7a, and 7b. Accordingly, pocket 17 is configured to
allow leaf spring 14 to
rest in platform 16 and to hold slider 12 in place in a first position wherein
the slider aperture 15
is misaligned with either aperture 11 of the platform 16. Specifically, leaf
spring 14 is driven
into pocket 17 using an appropriate tool 18 as shown in FIG. 5a. FIG. 5b
displays the top view of
the insertion of the leaf spring 14 into the platform using the tool 18. It
should be noted that leaf
spring 14 can be manually or mechanically placed into the platform sub-
assembly. Likewise
slider 12 is inserted either manually or mechanically as is shown in FIGS. 6a
and 6b. FIGS. 3,
7a, and 7b show the completed platform sub-assembly from differing views,
including isometric
and top views.
[0081] Referring to FIG. 4, the fully assembled cover assembly 30 includes
at least one
platform assembly 10 seated in the cover 20 behind the pair of apertures 29.
In one embodiment
the cover 20 and the platform sub-assembly 10 are held together by
interference fit.
[0082] FIG. 8 displays cover assembly 30 aligned with the base assembly 36
to be
combined to make tamper-resistant receptacle 40 shown in FIG. 9. Base assembly
36 includes
all elements associated with a known electrical receptacle (i.e. strap,
contacts, etc). The fully
assembled tamper resistant receptacle 40 in accordance with the present
invention is shown in
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FIG. 9. As shown, the outside of the 15 A, (125V) version of the tamper
resistant receptacle in
accordance with the present invention looks the same as an existing Leviton
receptacle with the
exception of the tamper-proof prong apertures. Accordingly, receptacle 40
offers the same
features relative to the mounting strap.
[0083] The receptacle 40, shown in FIG. 10, is shown as a duplex three-
prong electrical
receptacle for handling 15 amp current applications. However, it should be
understood that the
receptacle can be a single two or three-prong electrical receptacle or a
receptacle having
capabilities greater than that of a duplex receptacle. In addition, the
receptacle can have ground
fault circuit interrupter (GFCI) capabilities. Moreover, the receptacle can be
selected to handle
other current capacities such as 20 amp, 30 amp, and 50 amp and other
capacities.
[0084] For another perspective, FIG. 12 provides a top view of platform
16.
Furthermore, FIG. 13 provides a more detailed view of leaf spring 14.
Moreover, FIGS. 14a and
14b displays front and back views of slider 12 for a more direct view of the
ribs 13 formed on the
back side of slider 12.
[0085] FIGS. 10a and 10b, illustrate what happens when an electrical plug
having a pair
of prongs is inserted in the apertures of the cover 20. As shown in FIG. 10a,
just prior to having
a pair of prongs inserted through the apertures in cover 20, the slider 12
blocks direct entry into
the receptacle terminals formed by contacts 37. This first position for slider
12 is referred to as a
misaligned position. As prongs 19 are inserted further, projection 25 of
slider 12 slides into a
second position down the slope 27 such that slider aperture 15 comes into
alignment with one of
the prongs 19. FIG. 10b illustrates the slider in an intermediary position,
mid-way between the
first position and the second position. This second position is referred to as
an alignment
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position. As shown in FIG. 10b, projection 25 slides down slope 27 which
brings slider aperture
15 closer in alignment with one of prongs 19. Once the slider 12 transitions
completely to the
second position, slider 12 aligns with the cover apertures, 39 and 41, to
allow a first prong of
prongs 19 to bypass on side of slider 12 and a second prong of prongs 19 to
pass through slider
aperture 15. As such, the width of the slider 12 is designed such that the
other prong gains
clearance straight through to the receptacle terminal when slider aperture 15
aligns with the
aperture in cover 20. Thus, for this particular embodiment, the width between
the slider aperture
15 and far end of the slider 12 should substantially equal the width that
exists between the
apertures in the cover 20. The first and second prongs 19 engage with
receptacle terminals 37 to
complete electrical contact with 40 once slider 12 has transitioned completely
to the second
position.
[0086] As shown in FIG. 6a, leaf spring 14 rests in pocket 17 juxtaposed
to slider 12 in
the first position. When the slider 12 transitions to the second position, the
slider moves toward
the pocket 17 and the leaf spring 14. As a result, the leaf spring 14 is
compressed to the edge of
the platform 16. Leaf spring 14 is designed to retract to its original
position after being
compressed similar to a conventional spring. Thus, when the prongs 19 are
withdrawn, the leaf
spring 14 springs slider 12 back to the first position.
[0087] FIGS. ha and 11b, display what happens when a simple straight
insertion is
attempted only through either the cover aperture, 41 or 39, respectively. In
this case, when an
object is inserted into either aperture 39 or 41, slider 12 remains confined
in the misaligned
position or the first position. Specifically, FIG. lla illustrates an object
22 being inserted in the
aperture 41 of cover 20. As object 22 pushes slider 12 down towards the
platform 16, the lower
rib or projection 23 restricts the movement of the slider 12, such that slider
12 just tilts as oppose
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CA 02624409 2008-03-06
moving into the second position. Thereby, object 22 is prohibited from making
contact with
contacts 37 which form each receptacle terminal. In the alternative, FIG. 11b
displays an object
22 inserted in the aperture 39 of cover 20. As shown, slider 12 is pushed
downward towards
platform 16 and is restricted from further movement down the slope 27 due to
projection 21
formed in the cover 20. Similarly, as a result, slider 12 is disabled from
transitioning to the
second position. Thus, object 22 which probes the electrical receptacle 40
unsuccessfully makes
contact with the accessible power of contacts 37 which form the receptacle
terminal.
100881 It should be noted that while most tamper resistant receptacles
require a sloped
surface to be engaged by the plug prong in order to obtain a lateral move,
this mechanism
incorporates a flat surface (i.e. the top surface of slider 12) instead for
the prongs to push on in
combination with a sloped surface in the interior surface of the platform 16
that causes the slider
to move sideways as it is being pushed by prongs 19.
[0089] FIGS. 15-27 depict the component assemblies for a second embodiment
of the
tamper-resistant receptacle 300 in accordance with the present invention. The
receptacle 300, as
shown in FIG. 15, is a duplex three-prong electrical receptacle for handling
20 amp current
applications. However, it should be understood that the receptacle can be a
single two or three-
prong electrical receptacle or a receptacle other than that of a duplex
receptacle. In addition, the
receptacle can have ground fault circuit interrupter (GFCI) capabilities. The
receptacle also can
be selected to handle other current capacities such as 30 amp, 50 amp, and
other capacities.
100901 FIG. 15 shows an exploded view of the 20 ampere embodiment of the
tamper
resistant electrical receptacle in accordance with the present invention. From
the top of FIG. 15,
cover 150 sits on top of platform sub-assembly 100 including platform 106,
leaf spring 104 and
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CA 02624409 2008-03-06
slider 102. Terminal screws 256 connect the contacts 254 and wire nut 252
together within base
258. Screws 260 mounts strap 262 onto the base 258 using washers 264. Ground
screw 268
secures ground clamp 266 and ground clip 270 to strap 262.
[0091] In particular, and focusing upon the platform sub-assembly 100,
FIG. 16a
illustrates an exploded view of the platform sub-assembly 100 which includes a
slider 102, a leaf
spring 104, and a platform 106. Slider 102 includes at least one rib 120
displayed in FIGS. 22a,
22b, 24a and 24b. Similar to the previously described embodiment 40, it is
noted that rib 120
may be one or more than one projections (not shown). Slider 102 includes a
slider aperture 110
for alignment with the aperture of cover 150 which is explained in detail
hereinafter. Leaf spring
104 is mounted in the pocket 107 of platform 106 as is shown in the series of
FIGS. 18a, 18b,
19a, 19b, 20a, and 20b. FIGS. 23a and 23b, front and back views of leaf spring
104.
[0092] Accordingly, leaf spring 104 rests in the pocket 107 of platform
106 to bias slider
102 in place in a first position where the slider aperture 110 is misaligned
with either aperture
111 of the platform 106. Specifically, leaf spring 104 is driven into pocket
107 using an
appropriate tool 108 as shown in FIG. 18a. FIG. 18b displays the top view of
the insertion of the
leaf spring 104 into the platform using the tool 108. Although FIG. 18a refers
to the platform
assembly being manually assembled, it should be recognized by those skilled in
the art that leaf
spring 104 may be manually or mechanically inserted. FIGS. 19a and 19b show
the platform
sub-assembly being assembled by hand, wherein the slider is pushed into the
slot within the
platform juxtaposed to the leaf spring which holds the slider in place. The
fully assembled sub-
assembly 100 is shown in FIGS. 16b, 20a, and 20b includes the platform 106,
leaf spring 104,
and slider 102. These are placed in the cover assembly 200 as shown in FIG.
17.
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CA 02624409 2008-03-06
[0093] Referring to FIG. 17, the fully assembled cover assembly 200
includes at least
one platform assembly 100 seated in the cover 150 behind the pair of apertures
152. In one
embodiment the cover 150 and the platform sub-assembly 100 are held together
by interference
fit. The resulting cover assembly 200 is attached to the base assembly 250 as
shown in FIGS. 26
and 27 to form the tamper resistant electrical receptacle 300. Specifically,
FIG. 26 displays
cover assembly 200 aligned with the base assembly 250 to be combined to make
tamper-resistant
receptacle 300. Base assembly 250 includes all elements associated with a
known electrical
receptacle (i.e. strap, contacts, etc). The fully assembled tamper resistant
receptacle 300 in
accordance with the present invention is shown in FIG. 27. The outside of the
20 A, (125V)
version of the tamper resistant receptacle in accordance with the present
invention looks the
same as an existing Leviton receptacle with the exception of the tapered blade
slots. The tamper-
resistant receptacle offers the same features of the known receptacle
including but not limited to
those associated with the wrap around mounting strap. The marking on the face
of the tamper-
resistant receptacle helps to identify and distinguish it from the known
electrical receptacle.
[0094] In operation, slider 102 is initially in a first position where the
slider blocks each
aperture, 112 and 114, in the cover 150 as shown in FIGS. 21a and 22a. As
shown, leaf spring
104 engages the slider 102 in the first position wherein the slider aperture
110 is misaligned with
the aperture, 112 or 114, in the cover 150. As shown in FIG. 24a, rib 120 of
slider 102 comes in
contact with the cavity 118 of platform 106 allowing the slider 102 to move
laterally. Leaf
spring 104 biases slider 102 and retains the slider 102 to one side in a
position where the slider
aperture 110 is misaligned with either aperture, 112 or 114, in the cover 150.
Similar to the
previous embodiment as shown in FIG. 14b, it is noted that rib 120 may be more
than one rib on
the bottom slider 102.
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CA 02624409 2008-03-06
[0095]
Further, as shown in FIG. 24a when a conventional electrical plug having a
pair of
prongs are inserted into the cover 150 of receptacle 300 through the apertures
in cover 150, the
slider blocks entry into the receptacle terminals formed by contacts 117. As
the prongs 116 are
inserted further, the projection 120 of slider 102 slides into a second
position down into cavity
118 such that slider aperture 110 comes into alignment with one of the prongs
116. FIG. 24b
illustrates the slider 102 in an intermediary position, mid-way between the
first position and the
second position. As shown in FIG. 24b, projection 120 slides down into chamber
118 which
brings slider aperture 110 closer in alignment with one prong 116. Once the
slider 102
transitions completely to the second position, slider 102 aligns with the
cover apertures, 112 and
114, to allow a first prong of prongs 116 to bypass on side of slider 102 and
a second prong of
prongs 116 to pass through slider aperture 110. As such, the width of the
slider 102 is designed
such that the other prong gains clearance straight through to the receptacle
terminal when slider
aperture 110 aligns with the aperture in cover 150. When the slider 102 is in
the alignment
position, the prongs are allowed to enter through cover assembly 200 so as to
engage the contacts
117 that form the receptacle terminals for the receptacle 300. FIGS. 2 lb and
22b, illustrate the
alignment position wherein the slider 102 has shifted into the second position
providing
clearance for both apertures, 112 and 114, in cover 150. In this position,
slider 102 presses
against the leaf spring 104 and is held in the alignment position by the
prongs 116 which are
inserted therein. When the prongs 116 are removed, the biasing force of the
leaf spring 104
urges slider 102 back into the misaligned position as shown in FIGS. 21a and
22a. FIGS. 22a and
22b, depict the slider 102 in the first and second positions similar to FIGS.
21a and 21b, but from
a different angle.
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CA 02624409 2008-03-06
[0096] Specifically, FIGS. 24a and 24b, differ from FIGS. 25a and 25b, in
that the
viewing prospective of the diagram for FIGS. 24a and 24b, shows a cross-
section view of FIG.
27 taken along Section line A-A where the cut extends through receptacle 300
at the point
through either rib 120. FIGS. 25a and 25b, show a cross-section view of FIG.
27 taken along
Section line B-B which represents a cut through the space that lies between
ribs 120. Thus, rib
120 is not shown in FIGS. 25a and 25b since the cut is in the section between
the two part rib
120 (reference FIG. 14b).
[0097] In the case where an object is inserted into either aperture, the
slider 102 remains
confined in the misaligned position or the first position. FIGS. 25a and 25b,
display what
happens when an insertion is attempted in either aperture 112 and 114,
respectively. As depicted
in FIG. 25a when an object 126 is inserted in the aperture 114 of cover 150,
slider 102 is pushed
down towards the platform and is confined by a lower rib or projection 122.
Thus, even if a
determined attempt is made to force slider 102 in the aperture 114 of the
cover 150, projection
122 blocks the slider 102 from movement out of the first position where the
slider aperture 110 is
misaligned with the aperture in the cover 150. Object 126 is thereby
prohibited from making
contact with the contacts 117 that form the receptacle terminal.
[0098] FIG. 25b depicts an object 126 being inserted in aperture 112 of
cover 150. As
depicted therein, slider 102 pushes downward towards the platform 106 and only
limited
movement is permitted before the right edge (as shown) of slider 102 is
blocked from further
movement by projection or rib 124. Thus, projection 124 blocks slider 102 from
movement out
of the first position, wherein slider aperture 110 is misaligned with the
aperture in the cover 150.
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CA 02624409 2008-03-06
[0099] Note that while most tamper resistant concepts require a sloped
surface to be
engaged by the plug blade in order to obtain a lateral move, the tamper
resistant electrical
receptacle 100 in accordance with the present invention includes a flat
surfaced slider 102 for the
blades to push on. A sloped surface 120 in the interior surface of the slider
102 causes the slider
102 to move laterally into cavity 118 defined by platform 106.
[00100] FIGS. 28 and 29 discloses another embodiment of the present
invention
comprising a shutter having a different geometry than those of the embodiments
previously
described herein. As is depicted in FIG. 28a, a receptacle 300 in accordance
with this
embodiment comprises a shutter 301 shaped such that a locking end 304 is
adapted to nestle in
pocket 302, engage tab 308 or slide down ramp 309 depending on the type of
force applied to the
shutter. As shown in FIG. 28a, when prongs 305 and 306 are inserted into
apertures 310 and 311
respectively an evenly distributed force is placed on shutter 301 thereby
causing shutter 301
move from a first position as shown in FIG. 28A, to a second position as shown
in FIG. 28b.
[00101] With a balanced force applied to the shutter 301, the shutter 301
slides down ramp
309 thereby permitting prong 305 to slide past locking end 304 and allowing
prong 306 to
penetrate shutter aperture 312. This condition is depicted in FIG. 28b. In the
instance where a
projection is placed in only one of the apertures of the receptacle 300, the
shutter 301 is thereby
subjected to an unbalanced force and prevented from translating along ramp 309
by locking end
304. This condition is depicted in FIGS. 29a and 29b. FIG. 29a depicts the
resulting condition
when a projections placed in the left aperture of receptacle 300. When this
occurs, shutter 301 is
caused to pivot such that locking end 304 engages tab 308, thereby preventing
any translation of
shutter 301 from its initial position. FIG. 29b depicts the case where a
single projection is placed
in the right aperture of receptacle 300. When this occurs, shutter 301 is
again caused to pivot.
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CA 02624409 2008-03-06
However in this instance locking end 304 is made to fully nestle in pocket
302, thereby causing
locking end 304 to engage the body of the receptacle 300 and preventing
translation of shutter
301. This embodiment permits the shutter 301 to translate a distance greater
than that afforded
by the other embodiments of the invention. In this embodiment the preferred
distance is 0375"
whereas in the prior embodiments the preferred distance is 0.125".
1001021 Those of skill in the art will recognize that the physical
location of the elements
illustrated in FIGS. 1 and 15 can be moved or relocated while retaining the
function described
above. For example, the location and shape of the leaf spring may be adjusted
or reversed and
the function of the tamper resistant assembly in accordance with the present
invention will
remain.
[00103] Turning now to FIGS. 30-42C, a platform subassembly, for a
receptacle 40 (see
FIG. 1), according to another embodiment of the present disclosure, is
generally designated as
410. Platform subassembly 410 is substantially similar to platform subassembly
10 and thus will
only be discussed in detail herein to the extent necessary to identify
differences in construction
and operation thereof.
[001041 As seen in FIGS. 30 and 31, platform subassembly 410 includes a
platform 416
defining a pocket 417, a slider 412 at least partially slidably disposed
within pocket 417 of
platform 416, and a biasing member 414 interposed between platform 416 and
slider 412 in such
a manner so as to bias slider 412 to a home or blocking position within pocket
417 of platform
416.
[00105] As seen in FIGS. 34 and 35, slider 412 includes at least one rib
413 projecting
from a bottom surface thereof. Each rib 413 defines an angled, tapered or
sloped proximal
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CA 02624409 2008-03-06
surface 413a spaced a distance from the bottom surface of slider 412. Each
angled surface 413a
of ribs 413 terminates in a rounded distal end 413b. Distal end 413b of each
rib 413 has been
rounded in order to reduce any "picking" effects of slider 412 against
platform 416 and to
improve the performance thereof.
[00106] As seen in FIGS. 34 and 35, slider 412 further includes a
projection 413', axially
spaced from ribs 413, projecting from a bottom surface thereof. Projection
413' defines an
angled, tapered or sloped proximal surface 413a' that is oriented in a
direction substantially
parallel to angled surface 413a of ribs 413.
[00107] As seen in FIGS. 30-33 and 38, slider 412 further includes a slider
aperture 415
formed therein to enable one prong to be inserted therethrough to make contact
with the
receptacle terminals in the base of the tamper resistant receptacle 40. As
mentioned above, cover
20 of receptacle 40 may include at least one pair of apertures. As such,
slider aperture 415 must
align with at least one of the apertures from an aperture pair of cover 20 to
enable a prong to pass
through the slider aperture 415 to a receptacle terminal, as described above.
As seen in FIGS.
30-33, slider aperture 415 includes a ramped rear end portion 415a.
100108] As seen in FIGS. 30-33 and 38, platform 416 includes a pair of
apertures 411
formed in a bottom surface of pocket 417. Pocket 417 defines at least one
recess 417a therein, at
a location interposed between the pair of apertures 411. Recess 417a of
platform 416 is
configured and dimensioned to selectively receive and accommodate ribs 413 of
slider 412
therein. Each recess 417a defines an angled or sloped rear wall 417b, defining
a camming
surface for engagement and/or contact with angled surface 413a of ribs 413.
-27-
CA 02624409 2008-03-06
[00109] Pocket 417 may further define a second recess 418a at a location
adjacent one of
the pair of apertures 411, preferably on a side located furthest from sloped
rear wall 417b of first
recess 417a. Second recess 418a may also have an angled or sloped rear wall
418b, defining a
carmning surface for engagement and/or contact with angled surface 413a' of
projection 413'.
[001101 Biasing member 414, in the form of a leaf spring, is mounted in
cavity 417 of
platform 416 in a manner so as to bias or hold slider 412 in place in a first
position wherein
aperture 415 of slider 412 is misaligned with either aperture 411 of platform
416.
1001111 Assembly of platform subassembly 410 is accomplished in a manner
substantially
similar to platform subassembly 10 and thus will not be described in further
detail herein.
[001121 Turning now to FIGS. 41A and 41B, operation of platform subassembly
410 in a
receptacle, upon insertion of an electrical plug in the receptacle 40, is
shown and described. As
seen in FIGS. 41A and 41B, platform subassembly 410 is housed within
receptacle 40 at a
location between cover 20 and base 56 (including contacts 52).
[001131 As shown in FIG. 41A, just prior to having a pair of prongs
inserted through the
apertures in cover 20, slider 412 blocks direct entry into the receptacle
terminals 52. This first
position for slider 412 is referred to as a misaligned position. As prongs 19
are inserted further,
ribs 413 and projection 413' of slider 412 slide into a second position down
respective slopes or
camming surfaces 417b, 418b of platform 416 such that aperture 415 of slider
412 comes into
alignment with one of the prongs 19.
1001141 As shown in FIG. 41B, slider 412 is illustrated in an intermediary
position, mid-
way between the first position and the second position (i.e., an alignment
position). As shown in
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CA 02624409 2008-03-06
FIG. 41B, ribs 413 slide down slope 417b of recess 417a and projection 413'
slides down slope
418b of recess 418a thereby bringing aperture 415 of slider 412 closer in
alignment with one of
prongs 19. Once slider 412 transitions completely to the second position,
slider 412 aligns with
the cover apertures to allow a first prong of prongs 19 to bypass along a side
of slider 412 and a
second prong of prongs 19 to pass through aperture 415 of slider 412.
[00115] As such, the width of slider 412 is designed such that the other
prong gains
clearance straight through to the receptacle terminal when aperture 415 of
slider 412 aligns with
the aperture in cover 20. Thus, for this embodiment, the width between
aperture 415 of slider
412 and a far end of slider 412 should be substantially equal to the width
that exists between the
apertures in cover 20. The first and second prongs 19 engage with receptacle
terminals 52 to
complete electrical contact with 40 once slider 412 has transitioned
completely to the second
position.
[00116] As slider 412 is transitioning from the first position to the
second position, slider
412 acts on biasing member 414 to thereby bias biasing member 414. Biasing
member 414 is
designed to retract to its original position after being biased similar to a
conventional spring.
Thus, when the prongs 19 are withdrawn, biasing member 414 springs slider 412
back to the first
position.
[00117] As seen in FIGS. 41A and 41B, since each angled surface 413a of
ribs 413
terminates in a rounded distal end 413b, "picking" of slider 412 against
platform 416 has been
reduced and operability or slidability as been improved.
[00118] Turning now to FIGS. 42A-42B, there is illustrated what happens
when a simple
straight insertion is attempted only through one of the pair of cover
apertures 39 or 41. In this
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CA 02624409 2008-03-06
case, when an object is inserted into either aperture 39 or 41, slider 412
remains confined in the
misaligned position or the first position. Specifically, as seen in FIG. 42A,
when an object 22 is
inserted into aperture 39 of cover 20, object 22 pushes a proximal end of
slider 412 down in the
direction of platform 416 and restricts slider 412 from further movement down
surface 417b of
recess 417a of platform 416 due to the abutment of a front edge of slider 412
against a first
projection 21a formed in cover 20. First projection 21a of cover 20 restricts
the movement of
slider 412, such that slider 412 just tilts or cants as opposed to moving to
the second position. As
a result, slider 412 is disabled from transitioning to the second position.
Thus, object 22 which
probes the electrical receptacle 40 fails to make contact with the accessible
power of contacts 52
which form the receptacle terminal.
[00119] In the alternative, as seen in FIG. 42B, when an object 22a is
inserted into
aperture 41 of cover 20, object 22a pushes a distal end of slider 412 down in
the direction of
platform 416 and restricts slider 412 from further movement down surface 417b
of recess 417a
of platform 416 due to the abutment of an edge of projection 413' of slider
412 against a
projection or ledge 416' formed in platform 416. Ledge 416' of platform 416
restricts the
movement of slider 412, such that slider 412 just tilts or cants as opposed to
moving to the
second position. As a result, slider 412 is once again disabled from
transitioning to the second
position. Thereby, object 22a which probes the electrical receptacle 40 fails
to make contact
with the accessible power of contacts 52 which form the receptacle terminal.
[00120] Turning now to FIG. 42C, when an object 22b is inserted, at an
angle, into
aperture 41 of cover 20, object 22b will abut against and be blocked from
complete penetration
by a second wall or projection 21b extending from an inner surface thereof, at
a location between
apertures 39 and 41. Thereby, object 22b which probes the electrical
receptacle 40, at an angle,
-30-
CA 02624409 2008-03-06
fails to make contact with the accessible power of contacts 52 which form the
receptacle
terminal.
[00121] Turning now to FIGS. 43-50B, a platform subassembly for a 20 Amp
receptacle
540, according to another embodiment of the present disclosure, is generally
designated as 510.
Platform subassembly 510 is substantially similar to platform subassembly 10
and thus will only
be discussed in detail herein to the extent necessary to identify differences
in construction and
operation thereof.
[00122] As seen in FIGS. 43 and 44, platform subassembly 510 includes a
platform 516
defining a pocket 517, a slider 512 at least partially slidably disposed
within pocket 517 of
platform 516, and a biasing member 514 interposed between platform 516 and
slider 512 in such
a manner so as to bias slider 512 to a home or blocking position within pocket
517 of platform
516.
[00123] As seen in FIGS. 43-46, slider 512 includes a pair of slide ribs
513 projecting
from a bottom surface thereof. Each rib 513 defines an angled, tapered or
sloped proximal
surface 513a spaced a distance from the bottom surface of slider 512. Each
angled surface 513a
of ribs 513 terminates in a rounded distal end 513b, as seen in FIGS. 45 and
46, or a point as
shown in FIG. 44.
[00124] As seen in FIGS. 44 and 46, slider 512 further includes at least
one pocket 513',
axially spaced from ribs 513 in the direction of angled surface 513a, formed
in a bottom surface
thereof. Pocket 513' defines a first locking feature for slider 512.
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CA 02624409 2008-03-06
[00125] As seen in FIGS. 44 and 46, slider 512 further includes at least
one tab 512a
projecting from a bottom surface thereof and being located near a distal edge
thereof. Tab 512a
defines a surface against which biasing member 514 may act.
[00126] As seen in FIGS. 43-46, slider 512 further includes a slider
aperture 515 formed
therein to enable one prong to be inserted therethrough to make contact with
the receptacle
terminals in the base of the tamper resistant receptacle 540. As mentioned
above, cover 520 of
receptacle 540 may include at least one pair of apertures. As such, slider
aperture 515 must align
with at least one of the apertures from an aperture pair of cover 520 to
enable a prong to pass
through the slider aperture 515 to a receptacle terminal, as described above.
[00127] As seen in FIG. 45, a top surface of slider 512 defmes a pair of
angled surfaces
512b', 512b" extending into slider 512. Angled surfaces 512b', 512b" are
oriented in a pair of
parallel planes. As seen in FIG. 45, angled surface 512b' begins near or at a
proximal edge of
slider 512 and extends through to slider aperture 515, meanwhile, angled
surface 512b" begins
at a location spaced a distance distal of slider aperture 515 and extends
through a distal edge of
slider 512.
[00128] With continued reference to FIGS. 43-46, slider 512 includes a
proximal-most
wall 512c extending from an upper surface thereof at the proximal edge
thereof. Slider 512
further includes an intermediate wall 512d extending from the upper surface
thereof at a location
extending from a distal edge of slider aperture 515. Slider 512 further
includes a distal pin or
catch feature 512e extending from the upper surface thereof at the distal edge
thereof.
[00129] As seen in FIGS. 43, 44 and 47, platform 516 includes a pair of
apertures 511
formed in a bottom surface of pocket 517. Pocket 517 defines a pair of
recesses 517a therein, at
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CA 02624409 2008-03-06
a location flanking the pair of apertures 511. Recesses 517a of platform 516
are configured and
dimensioned to selectively receive and accommodate ribs 513 of slider 512
therein. Each recess
517a defines an angled or sloped rear wall 517b, defining a camming surface
for engagement
and/or contact with angled surface 513a of ribs 513.
[00130] Pocket 517 may further define a second recess 518a at a location
adjacent one of
the pair of apertures 511, preferably on a side located near or at a distal
end of platform 516.
Second recess 518a may also an angled or sloped rear wall 518b, defining a
camming surface for
engagement and/or contact with tab 512a projecting from slider 512, as
described above.
[00131] Platform 516 includes a ramp feature 516a projecting from and
bottom wall
thereof at a location near a proximal aperture of the pair of apertures 511.
Ramp feature 516a
may be located adjacent a first side edge of the proximal aperture of the pair
of apertures 511.
Platform 516 further includes a pin or capture feature 516b projecting from
and bottom wall
thereof at a location near the proximal aperture of the pair of apertures 511.
Capture feature
516b may be located adjacent a second side edge of the proximal aperture of
the pair of apertures
511.
[00132] Biasing member 514, in the form of a leaf spring, is mounted in
cavity 517 of
platform 516 in a manner so as to bias or hold slider 512 in place in a first
position wherein
aperture 515 of slider 512 is misaligned with either aperture 511 of platform
516.
[00133] Assembly of platform subassembly 510 is accomplished in a manner
substantially
similar to platform subassembly 10 and thus will not be described in further
detail herein.
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CA 02624409 2008-03-06
[00134] Turning now to FIGS. 49A and 49B, operation of platform subassembly
510 in a
receptacle, upon insertion of an electrical plug in the receptacle 540, is
shown and described. As
seen in FIGS. 49A and 49B, platform subassembly 510 is housed within
receptacle 540 (see FIG.
43) at a location between cover 520 and base 556 (including contacts 552).
[00135] As shown in FIG. 49A, just prior to having a pair of prongs
inserted through the
apertures in cover 520, slider 512 blocks direct entry into the receptacle
terminals 552. This first
position for slider 512 is referred to as a misaligned position. As prongs 19
are inserted further,
ribs 513 of slider 512 slide into a second position down respective slopes or
camming surfaces
517b of recesses 517a formed in platform 516 such that aperture 515 of slider
512 comes into
alignment with one of the prongs 19.
[00136] As shown in FIG. 49B, slider 512 is illustrated in the second
position (i.e., an
alignment position). As shown in FIG. 49B, ribs 513 slide down slope 517b of
recess 517a and
tab 512a slides down slope 518b of recess 518a thereby bringing aperture 515
of slider 512 in
alignment with one of prongs 19. With slider 512 transitioned completely to
the second position,
slider 512 aligns with the cover apertures to allow a first prong of prongs 19
to bypass along a
side of slider 512 and a second prong of prongs 19 to pass through aperture
515 of slider 512.
[00137] As such, the width of slider 512 is designed such that the other
prong gains
clearance straight through to the receptacle terminal when aperture 515 of
slider 512 aligns with
the aperture in cover 520. Thus, for this embodiment, the width between
aperture 515 of slider
512 and a far end of slider 512 should be substantially equal to the width
that exists between the
apertures in cover 520. The first and second prongs 19 engage with receptacle
terminals 552 to
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complete electrical contact with 540 once slider 512 has transitioned
completely to the second
position.
[00138] As slider 512 is transitioning from the first position to the
second position, slider
512 acts on biasing member 514 to thereby bias biasing member 514. Biasing
member 514 is
designed to retract to its original position after being biased similar to a
conventional spring.
Thus, when the prongs 19 are withdrawn, biasing member 514 springs slider 512
back to the first
position.
[00139] As seen in FIGS. 45 and 46, in an embodiment, if each angled
surface 513a of
ribs 513 terminates in a rounded distal end 513b, "picking" of slider 512
against platform 516
may be reduced and operability or slidability may be improved.
[00140] Turning now to FIGS. 50A-50B, there is illustrated what happens
when a simple
straight insertion is attempted only through one of the pair of cover
apertures 39 or 41. In this
case, when an object is inserted into either aperture 39 or 41, slider 512
remains confined in the
misaligned position or the first position. Specifically, as seen in FIG. 50A,
when an object 22 is
inserted into aperture 39 of cover 520, object 22 pushes a proximal end of
slider 512 down in the
direction of platform 516 and restricts slider 512 from further movement down
surface 517b of
recess 517a of platform 516 due to the insertion of capture feature 516b of
platform 516 in
pocket 513' of slider 512.
[00141] Capture feature 516b of platform 516 restricts the movement of
slider 512, such
that slider 512 just tilts or cants as opposed to moving to the second
position. As a result, slider
512 is disabled from transitioning to the second position. Thus, object 22
which probes the
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CA 02624409 2008-03-06
electrical receptacle 540 fails to make contact with the accessible power of
contacts 552 which
form the receptacle terminal.
1001421 In the alternative, as seen in FIG. 50B, when an object 22a is
inserted into
aperture 41 of cover 520, object 22a pushes a distal end of slider 512 down in
the direction of
platform 516 and restricts slider 512 from further movement down surface 517b
of recess 517a
of platform 516 due to the insertion of catch feature 512e of slider 512 in a
recess 520a formed in
an inner surfaced of cover 520. Ledge 416' of platform 416 restricts the
movement of slider 412,
such that slider 412 just tilts or cants as opposed to moving to the second
position. As a result,
slider 412 is once again disabled from transitioning to the second position.
Thereby, object 22a
which probes the electrical receptacle 40 fails to make contact with the
accessible power of
contacts 52 which form the receptacle terminal.
[00143] Advantages of this design include but are not limited to a tamper-
resistant
electrical wiring device system having a high performance, simple, and cost
effective design.
[00144] The reader's attention is directed to all papers and documents
which are filed
concurrently with this specification and which are open to public inspection
with this
specification, and the contents of all such papers and documents are
incorporated herein by
reference.
[00145] All the features disclosed in this specification (including any
accompanying
claims, abstract and drawings) may be replaced by alternative features serving
the same,
equivalent or similar purpose, unless expressly stated otherwise. Thus, unless
expressly stated
otherwise, each feature disclosed is one example only of a generic series of
equivalent or similar
features.
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CA 02624409 2008-03-06
[001461 The
terms and expressions which have been employed in the foregoing
specification are used therein as terms of description and not of limitation,
and there is no
intention in the use of such terms and expressions of excluding equivalents of
the features shown
and described or portions thereof, it being recognized that the scope of the
invention is defined
and limited only by the claims which follow.
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