Electrical receptacle assembly

An electrical plug-receiving receptacle includes a housing enclosure with an opening and a cover for closing the opening. The housing enclosure has walls defining at least a portion of the periphery of the opening, including an outside wall and a generally flexible inside wall spaced from the outside wall. The inside wall has an aperture spaced from the opening. The cover includes a generally rigid inner arm for positioning inside the flexible inside wall of the housing enclosure and a generally rigid outer arm for positioning between the inside and the outside walls of the enclosure. The inner and outer arms define a tortuous passage therebetween for insertion thereinto of the inside wall of the housing enclosure. The inner arm has a latching nib for latching engagement in the aperture in the inside wall of the enclosure. The inside wall must bend when inserted into the tortuous passage. The cover may include a heat sink.

FIELD OF THE INVENTION 
This invention generally relates to the art of electrical connectors and, 
particularly, to an electrical plug-receiving receptacle assembly. 
BACKGROUND OF THE INVENTION 
Electrical receptacles for accepting the prongs of electrical plugs to 
connect an electrical line to a source of electrical power have been 
designed as self-contained units or for mounting in junction boxes. 
Electrical terminals or contacts to which incoming power, neutral and 
grounding wires are connected, as well as other receptacle components, 
normally are enclosed within a housing means, such as a two-part assembly 
to form a protective enclosure for the components. The two housing parts 
may be maintained in assembled relationship by means of screws or other 
such fasteners installed as part of the assembly operation. Such screws 
may be easily removed, of course, permitting disassembly of the receptacle 
by end users of the receptacles. 
In efforts to eliminate such extraneous items as screws or other fastening 
components, two-part receptacle assemblies have been designed with 
integral latch means to permit assembly in a more rapid and efficient 
manner. Such latching systems most often are used when the two-part 
housing assembly is fabricated of plastic material, i.e. each part is 
unitarily molded of plastic. 
One of the problems in providing latching systems in electrical receptacles 
with multi-part plastic housing enclosures is that the walls of the 
enclosures often are thin and rather flexible. If latching devices are 
provided on flexible walls, for instance, it may be difficult to provide a 
reliable latching system, particularly if it is desirous to make it 
difficult to disassemble the receptacle or to make disassembly 
substantially impossible without destroying the receptacle. Consequently, 
with thin-walled constructions, the walls must .be thickened in areas 
where the latching devices are provided, or extraneous latching 
protuberances have been provided, projecting outwardly of the housing 
enclosure, as was done in U.S. Pat. No. 4,872,087 to Brant, dated Oct. 3, 
1989. 
The present invention is directed to solving such problems as identified 
above with providing a latching system in flexible and/or thin walled 
receptacle housing enclosures, without providing outwardly protruding 
latch devices and without having to thicken the walls of the receptacle to 
provide an adequate latching system. 
SUMMARY OF THE INVENTION 
An object, therefore, of the invention is to provide a new and improved 
electrical receptacle of the character described. 
In the exemplary embodiment of the invention, an electrical receptacle is 
disclosed to include a housing enclosure with an opening and cover means 
for generally closing at least a portion of the opening. The housing 
enclosure has a generally thin flexible wall with an aperture spaced 
inwardly of the opening. The cover means includes a generally rigid inner 
arm for positioning inside the flexible wall of the housing enclosure and 
a generally rigid outer arm for positioning outside the flexible wall. The 
inner and outer arms define a tortuous passage therebetween for insertion 
thereinto of the flexible wall such that the flexible wall must bend when 
inserted into the tortuous passage. Complementary interengaging latch 
means are provided between the flexible wall and the inner arm for 
latching the cover means to the housing enclosure when the flexible wall 
is inserted into the tortuous passage. 
As disclosed herein, the aforementioned thin flexible wall is provided as 
an inside wall spaced inwardly from an outside flexible wall of the 
housing enclosure. The outside wall defines at least a portion of the 
periphery of the opening in the housing enclosure, and the outside wall is 
disposed outside the outer arm of the cover means, whereby the latch means 
is located entirely within the enclosure and does not protrude outwardly 
therefrom. 
In one embodiment of the invention, the cover means is a one-piece 
structure and includes a generally planar closing wall, with the inner and 
outer arms projecting therefrom into the opening in the housing enclosure. 
The latch means is provided by an aperture in the flexible inside wall of 
the housing enclosure and a latching nib on the rigid inner arm of the 
cover means. The outer arm of the cover means has a ramped inside surface 
which effectively narrows the tortuous passage on one side of the latching 
nib to a dimension narrower than that of the flexible inside wall of the 
housing enclosure to force the inside wall to bend around the latching nib 
when inserted into the passage. The latching nib has a chamfered surface 
engageable by the inside wall when inserted into the passage to facilitate 
bending of the inside wall around the latching nib. 
In an alternative embodiment of the invention, the cover means include a 
heat sink means. In particular, the cover means is a two-part structure 
including a frame part having the generally rigid inner arm thereon and a 
heat sink part having the generally rigid outer arm and the heat sink 
means thereon. 
Complementary interengaging abutment means also are provided between the 
inside wall of the housing enclosure and the inner arm of the cover means 
to prevent lateral movement between the enclosure and the cover means. The 
abutment means are provided by a flange on the inside wall extending 
generally parallel to the passage and engageable by the inner arm of the 
cover means. 
Other objects, features and advantages of the invention will be apparent 
from the following detailed description taken in connection with the 
accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in greater detail, FIGS. 1-7 show one embodiment 
of the invention, and FIGS. 8-10 show an alternate embodiment of the 
invention. Referring first to FIG. 1, an electrical plug-receiving 
receptacle, generally designated 10, includes a housing enclosure, 
generally designated 12, and a cover means in the form of a one-piece 
cover, generally designated 14. The housing enclosure defines an opening 
16, and the cover is adapted for closing this opening. It should be 
understood that receptacle 10 is intended to house or enclose terminals or 
contacts to which incoming power, neutral and grounding wires are 
connected, as well as other receptacle components. The terminals and the 
other components, etc. are not shown in the drawings, because they are 
well known in the art and their depiction would unduly clutter the 
figures. 
Housing enclosure 12 is unitarily molded of dielectric material such as 
plastic or the like and includes wall means defining a substantial portion 
of the periphery of opening 16. The wall means include outside side walls 
18 and an end wall 20 bounding three sides of opening 16, along with a 
bottom wall 22 which closes the bottom of the opening. A tab 24 projects 
upwardly from the upper edge of rear wall 20. It can be seen that side 
walls 18 are relatively thin and, being fabricated of plastic material, 
the side walls are considerably flexible and not amenable to providing 
reliable latching devices thereon. 
Housing enclosure 12 further includes a pair of generally flexible inside 
walls 26 which are spaced inwardly from outside side walls 18 near the 
front edges thereof. Front wall portions 28 join inside walls 26 with 
outside walls 18 in generally U-shaped configurations. Each flexible 
inside wall 26 includes a latching aperture 30 spaced from opening 16, and 
a vertical flange 32 which projects inwardly from the respective inside 
wall. 
Referring to FIG. 2 in conjunction with FIG. 1, cover 14 is a one-piece 
structure and includes a generally planar closing wall 34 having a slot 36 
through which tab 24 of housing enclosure 12 projects. A hole 38 is formed 
in the cover adjacent slot 36, and this hole is provided as a port through 
which a probe of a testing or recording unit can be inserted. The cover 
also has a front wall 40 which is inserted between flexible inside walls 
26 of housing enclosure 12. Cover 14, like housing enclosure 12, is 
unitarily molded of dielectric material such as plastic or the like. 
Front wall 40 is rigid and the sides thereof define inner arms 42 for 
positioning inside flexible inside walls 26 of the housing enclosure. A 
generally rigid outer arm, generally designated 44, depends from planar 
wall 34 of cover 14 for positioning between each inside flexible wall 26 
and the respective outside flexible wall 18 of the housing enclosure. As 
best seen in FIG. 2, a ramped surface 46 is formed on the inside of each 
outer arm 44. As best seen in FIG. 1, a stiffening or rigidifying rib 48 
is formed on the outside of each arm 44. A latching nib 50 projects 
outwardly from each inner arm 42, and each nib includes a chamfered bottom 
surface 52. As seen in FIG. 2, front wall 40 has a pair of holes 54 which 
are provided as screw holes for accepting a strain relief plate (not 
shown) of the receptacle assembly. Lastly, the top of the cover also has a 
pair of holes 56 (FIG. 1) for mounting the entire receptacle to an 
appropriate supporting surface means (not shown). 
It should be understood that inner "arms" 42 are provided by the sides of 
front wall 40 of cover 14, because the invention is illustrated in the 
particular embodiment of a receptacle assembly which includes the front 
wall. However, it should be understood that separate inner rigid arms 
could be provided spaced inwardly of outer rigid arms 44 to define 
passages therebetween into which flexible inner walls 26 of housing 
enclosure 12 can be inserted in the direction of arrows "A" (FIG. 2). 
More particularly, the invention contemplates that inner rigid arms 42 and 
outer rigid arms 44 of cover 14 define tortuous passages as indicated by 
arrows "B" (FIG. 2). The arrows are shown to curve around latching nibs 50 
and upwardly between the inner and outer arms along ramped inside surfaces 
46 of the outer arms. It also can be seen that the ramped surfaces 52 
effectively narrow the passages on the upper sides of latching nibs 50 if 
the passages were considered to be in straight lines. Therefore, reference 
is made to FIG. 4 which shows how inner flexible arms 26 must bend when 
inserted into the tortuous passages between the inner and outer arms 42 
and 44, respectively, as the passages are defined by latching nibs 50 and 
ramped inside surfaces 46. 
In comparing FIGS. 3 and 4, as flexible inside walls 26 move into the 
passages between the inner and outer arms of the cover in the direction of 
arrow "C" (FIG. 4), the flexible walls eventually reach positions as shown 
in FIG. 3 whereupon apertures 30 in the flexible inside walls 26 of the 
housing enclosure snap about latching nibs 50. It can be seen that the 
flexible inside walls 26, in their latching condition as shown in FIG. 3, 
are generally planar as in their original unstressed condition as shown in 
FIGS. 1 and 2. In the fully latched condition of receptacle 10, with cover 
14 latched onto the top of housing enclosure 12 as shown in FIG. 3, the 
receptacle cannot be disassembled or opened without substantially or 
completely destroying the structure. 
FIGS. 5 and 6 show another feature of the invention wherein the inwardly 
directed flange 32 of each inside flexible wall 26 of housing enclosure 12 
is located laterally of an inside edge 60 of the respective outer arm 44 
of the cover. Therefore, when the cover is assembled to the housing 
enclosure as shown in FIG. 6, the outer arms 44 abut against flanges 32 to 
prevent lateral movement between the cover and the housing enclosure. 
FIGS. 5 and 6 also show that flexible inside walls 26 of housing enclosure 
12, along with generally rigid outer arms 44 of cover 14 extend inwardly 
of latching nibs 50 in a lateral direction, i.e. to the right as viewed in 
FIGS. 5 and 6. Therefore, not only must the flexible inside walls 26 bend 
around latching nibs 50 as shown in FIG. 4, but the flexible walls also 
twist about the latching nibs (i.e. about vertical axes) at the inside 
edges of the nibs during assembly. 
FIG. 7 shows the full bottom wall 22 of housing enclosure 12 to better 
illustrate the location of inside flexible walls 26 in relation to outside 
flexible walls 18. In addition, a plurality of slots 62 and 64 are shown 
in the bottom walls. These slots are for insertion therethrough of the 
prongs of an appropriate electrical plug (not shown). 
FIGS. 8-10 show an alternative embodiment of the invention wherein the 
cover means is in the form of a two-part structure including a heat sink 
means. In other words, the electrical plug-receiving receptacle of the 
invention may be used in an application wherein a dimmer block may be 
employed in the circuitry within the housing enclosure. The dimmer block 
generates heat, and a heat sink means is employed to dissipate the heat. 
More particularly, in the embodiment of FIGS. 8-10, a cover means, 
generally designated 70, is employed in conjunction with a housing 
enclosure identical to housing enclosure 12 described above in relation to 
the embodiment of FIGS. 1-7. Therefore, like numerals have been applied to 
the components of housing enclosure 12 corresponding to like components 
described above, and the description of the housing enclosure will not be 
repeated. 
Referring to FIGS. 8-10 in particular, cover means 70 is a two-part 
structure including a frame part, generally designated 72, and a heat sink 
part, generally designated 74. In essence, frame part 72 includes a 
generally planar wall 76, similar to closing wall 34 of cover 14, but 
including a rather large opening 78. The planar wall includes a slot 80 
through which tab 24 of housing enclosure 12 projects, along with a hole 
82 provided as a port through which a probe of a testing or recording unit 
can be inserted. Frame part 72 includes a rigid front wall 40, with the 
sides thereof defining inner arms 42 having a latching nib 50 projecting 
outwardly from each inner arm, and each nib including a chamfered bottom 
surface 52. These reference numerals correspond to the above description 
of the front wall, inner arms and latching nibs of the embodiment in FIGS. 
1-7. In addition, front wall 40 again has a pair of holes 54 which are 
provided as screw holes for accepting a strain relief plate (not shown) of 
the receptacle assembly. 
Heat sink part 74 includes a generally rectangular peripheral wall 84 which 
underlies planar wall 76 of frame part 72 when in assembled condition as 
shown in FIG. 10. Peripheral wall 84 includes a pair of holes 85 (FIG. 8) 
for mounting the entire receptacle to an appropriate supporting surface 
means (not shown). Heat sink part 74 includes a plurality of 
heat-dissipating fins 88 which are secured to or integral with peripheral 
wall 40 in a generally parallel, spaced relationship with each other. The 
array of heat-dissipating fins project upwardly through opening 78 in 
frame part 72 when cover means 70 is in assembled condition as shown in 
FIG. 10. Front wall 40 of frame part 72 projects downwardly through an 
opening 86 in heat sink part 74. Lastly, the heat sink part has an opening 
89 aligned with hole 82 in the frame part and through which tab 24 of 
housing enclosure 12 projects. Either the entire heat sink part 74, or at 
least the heat-dissipating fins thereof, are fabricated of a heat 
conductive material to conduct and dissipate to atmosphere heat generated 
from electrical components within housing enclosure 12, such as a dimmer 
block, as described above. 
Whereas generally rigid outer arm 44 in the embodiment of FIGS. 1-7 is 
formed integrally with and depends from planar wall 34 of cover 14, in the 
alternative embodiment of FIGS. 8-10, a pair of generally rigid outer arms 
90 project downwardly from peripheral wall 84 for positioning between each 
inside flexible wall 26 and the respective outside flexible wall 18 of 
housing enclosure 12, as best seen in FIG. 10. Other than the fact that 
cover means 70 in the embodiment of FIGS. 8-10 is a two-part structure to 
include a heat sink means, the function and operation of assembling the 
plug-receiving receptacle, including inner arms 42 and latching nibs 52 on 
frame part 72, along with rigid outer arms 90 on heat sink part 74, in 
conjunction with outside and inside flexible walls 18 and 26, 
respectively, of the housing disclosure are substantially the same and 
will not be repeated herein. 
It will be understood that the invention may be embodied in other specific 
forms without departing from the spirit or central characteristics 
thereof. The present examples and embodiments, therefore, are to be 
considered in all respects as illustrative and not restrictive, and the 
invention is not to be limited to the details given herein.