Note: Descriptions are shown in the official language in which they were submitted.
CA 02721289 2010-11-10
DEVICE FOR MAINTAINING
A PLUG AND SOCKET CONNECTION
BETWEEN TWO ELECTRICAL CORDS
Field of the Invention
[00011 This invention relates to devices used to prevent accidental
disconnection of
electrical plug and socket connections attached to conductor cords. It also
relates to
preventing deflection of electrical plug and socket connections, as well
snagging and the
like, when cords are being pulled or dragged, such as when working with power
tools.
Description of the Related Art
[00021 Tradespeople working on home improvements and home maintenance
commonly use power tools plugged into electrical extension cords for many
purposes.
When being pulled or dragged, the electrical plug and socket connection
regularly comes
apart, snags or both. Electrical cords are sometimes tied into knots to
prevent such
disconnections, but this causes strain on the cords and increases snagging.
[00031 It is known to provide a device for maintaining a plug and socket
connection
having a pair of spaced-apart end portions connected together by elongate flat
elastic
bands, where each end portion has a slit for receiving a respective cord and
where the end
portions stretch over the plug and socket connection. For example, please see
the device
shown in United States Patent No. 5,713,753 to Bayer or United States Patent
No.
5,443,397 to Carl. However, such slits may be difficult to open and, as a
result, it may be
difficult to insert the cords. This problem is exacerbated when a user needs
to switch
between a variety of power tools during the course of the day, discouraging a
user from
using such devices. In order to facilitate the opening of the slits, a high
degree of
elasticity in the end portion material may be required; however, such a high
degree of
elasticity may reduce the ability of the device to hold the cords together.
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[00041 Also, protruding parts, such as flanges 72 and 74 in the device shown
in Carl,
may inhibit the device's deflective capability, rending the device more prone
to snagging
of the device on sharp corners, edges and the like. This not only may be
extremely
irritating but can be very dangerous. If for instance the user were operating
a large router
with a large digging bit and the device snagged, the resulting uneven
pressures can cause
the router to jump wildly. This in turn can cause damage to the material being
worked on
and possibly also cause serious injury to the operator of the router.
[00051 The elongate flat nature of the elastic bands of the known prior art
may also
cause the bands to prematurely tear due to the difficulty in molding uniform
bands in
such a shape. After molding the exterior of the bands will typically cool
faster than the
interior of the bands. As a result, the bands may exhibit non-uniform
elasticity, which in
turn may promote failure.
BRIEF SUMMARY OF INVENTION
[00061 The present invention as disclosed herein provides a device for
maintaining a
plug and socket connection between two electrical cords that overcomes the
above
disadvantages. It is an object of the present invention to provide an improved
device for
maintaining a plug and socket connection between two electrical cords.
[00071 There is accordingly provided a device used to maintain a plug and
socket
connection between two electrical cords. The device includes a pair of spaced-
apart
frustoconical members. Each frustoconical member is in the shape of a
truncated, partial
cone. Each frustoconical member has an inner end and an outer end spaced-apart
from
the inner end. Each outer end is smaller in cross-section relative to its
corresponding
inner end. Each frustoconical member has a tapered exterior surface that
extends between
its inner end and its outer end. Each frustoconical member has a central
passageway for
receiving a corresponding one of the cords. The passageways extend from their
corresponding inner ends to their corresponding outer ends, respectively. Each
frustoconical member has a pair of sides configured for guiding said one of
the cords to
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its central passageway. Each of the sides extends from the tapered exterior
surface to the
central passageway. The sides are angularly spaced-apart with respect to each
other by an
angle between 90 and 120 degrees, forming a channel therebetween. The device
includes
a pair of elastic connecting members extending from and being disposed between
the
inner ends of the frustoconical members. The connecting members are configured
to
stretch over the plug and socket and bias the inner ends of the frustoconical
members
against outer ends of the plug and socket. The device thereby maintains the
plug and
socket connection.
[00081 There is also provided a device used to maintain a plug and socket
connection
between two electrical cords. The device includes a pair of spaced-apart
frustoconical
members. Each frustoconical member has an inner end and an outer end spaced-
apart
from the inner end. The outer ends are smaller in cross-section relative to
the inner ends.
Each frustoconical member has a tapered exterior surface that extends between
its inner
end and its outer end. Each frustoconical member has a central passageway for
receiving
a corresponding one of the cords. The passageways extend from the inner ends
to the
outer ends, respectively. Each frustoconical member has a longitudinal channel
configured for guiding said one of the cords to its corresponding central
passageway. The
longitudinal channels extend from the tapered exterior surfaces to the central
passageways. Each frustoconical member includes a pair of spaced-apart,
opposed inner
walls defining a space therebetween to facilitate insertion of the cord into
its central
passageway. Each pair of inner walls extends between the corresponding inner
end and
the corresponding outer end, extending from a respective side of its central
passageway to
the channel and being spaced-apart from each other at a distance equal to or
greater than
the cross-sectional diameter of the passageway. The device includes a pair of
elastic
connecting members extending from and disposed between the inner ends of the
frustoconical members. The connecting members are configured to stretch over
the plug
and socket, thereby biasing the inner ends of the frustoconical members
against outer
ends of the plug and socket for maintaining the plug and socket connection.
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[00091 According to another aspect, there is provided a device used to
maintain a
plug and socket connection between two electrical cords. The device is made of
an elastic
material. The device includes a pair of spaced-apart frustoconical members.
Each
frustoconical member is in the shape of a truncated, partial cone. Each
frustoconical
member has an inner end. Each inner end includes a bevelled peripheral portion
disposed
to face at least partially outwards from the device. Each bevelled peripheral
portion is
configured to inhibit its inner end from getting caught on objects. Each
frustoconical
member has an outer end spaced-apart from its corresponding inner end. The
outer ends
are smaller in cross-section relative to the inner ends. The outer ends are
relatively
flexible compared to the inner ends to accommodate bending and deflection of
portions
of the cords adjacent thereto. Each frustoconical member has a tapered
exterior surface
that extends between its inner end and its outer end. Each frustoconical
member has a
central passageway for receiving a corresponding one of the cords. Each
passageway
extends from its corresponding inner end to its corresponding outer end. Each
frustoconical member has a longitudinal channel configured for guiding said
one of the
cords to the central passageway. The channels are quadrant-shaped in cross-
section. Each
frustoconical member has a pair of spaced-apart, opposed recesses and inner
walls
configured for facilitating disposal of an initial portion of the cord into
its central
passageway. Each pair of recesses is disposed between the inner end and the
outer end, is
in communication with opposite sides of the central passageway, and at least
partially
extends through portions of the frustoconical member surrounding the channel.
Each
recess is in the shape of a triangular prism. Each inner wall is adjacent to a
respective one
of the recesses and tangentially extends from the central passageway to the
channel. The
device includes a pair of elastic connecting members extending from and being
disposed
between the bevelled peripheral portions of the inner ends of the
frustoconical members.
The connecting members are round in cross-section and the bevelled peripheral
portions
are disposed to facilitate outward stretching of the connecting members. The
connecting
members are configured to stretch over the plug and socket, thereby biasing
the inner
ends of the frustoconical members against outer ends of the plug and socket
for
maintaining the plug and socket connection.
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[0010] The device as herein described may be referred to as a plug harness.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The invention will be more readily understood from the following
description
5 of preferred embodiments thereof given, by way of example only, with
reference to the
accompanying drawings, in which:
Figure 1 is a top view of a plug harness attached to two electrical cords and
a plug and
socket connection, the plug harness having two spaced-apart frustoconical
members,
according to one embodiment, connected together with a pair of elastic
connecting
members, the plug and socket connection being disposed therebetween;
Figure 2 is an end elevation view of the plug harness shown in Figures 1;
Figure 3 is a sectional view along lines 3 - 3 of Figure 1;
Figure 4 is a bottom plan view of a plug harness according to another
embodiment;
Figure 5 is a side elevation view of the plug harness shown in Figure 4, with
the bottom
of the plug harness facing up from the perspective of the figure;
Figure 6 is a top plan view of the plug harness shown in Figure 4;
Figure 7 is a side elevation view of the side opposite Figure 5, with the top
side of the
plug harness facing up from the perspective of the figure;
Figure 8 is an end view of the plug harness shown in Figure 5; and
Figure 9 is a sectional view along lines 9 - 9 of Figure 6.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] Referring to the drawings and first to Figure 1, the present
application is
directed to a plug harness 10. The plug harness is made of a flexible elastic
material, such
as plastic, and in this example is specifically made of polyurethane though it
could be
made of other elastic materials. The plug harness in this example is a one-
piece device
made via a multiple part injection type mold though it could be assembled from
multiple
parts.
[0013] The plug harness 10 includes a pair of frustoconical members 12 and 14.
Frustoconical members 12 and 14 have substantially identical configurations
and
function. The frustoconical members are configured to snap onto electrical
cords 11 and
13, which have a plug 15 and a socket 17 connected together via a plug and
socket
connection 19.
[0014] Each of the frustoconical members 12 and 14 is in the shape of a
truncated,
partial cone. Frustoconical members 12 and 14 have inner ends 16 and 18
configured to
face one another. Inner ends 16 and 18 are shaped to abut the exterior ends or
shoulders
and 22 of the plug 15 and socket 17, respectively. Inner ends 16 and 18 of the
frustoconical members include bevelled peripheral portions 24 and 26. The
bevelled
peripheral portions are partially annular in shape, as seen for portion 26 in
Figure 3, are
20 disposed to face each other and are also disposed to face at least
partially outwards with
respect to the plug harness 10. The bevelled peripheral portions 24 and 26 so
shaped,
advantageously, inhibit the inner ends 16 and 18 of the frustoconical members
from
getting caught on corners, sharp edges and the like.
[0015] The frustoconical members 12 and 14 have outer ends 28 and 30 spaced-
apart
from the inner ends 16 and 18. The outer ends 28 and 30 face away from each
other and
are smaller in cross-section relative to the inner ends 16 and 18 of the
frustoconical
members. The tapered and conical nature of the frustoconical members 12 and
14, with
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its relatively small outer ends, enables the plug harness to readily deflect
around and over
corners and snags when pulled or dragged.
[00161 Also, the outer ends so shaped are relatively flexible compared to the
inner
ends since they are thinner. Thus, the outer ends are configured to
accommodate bending
and deflections of portions of the cords 11 and 13 adjacent thereto while the
plug harness
10, with its inner ends 16 and 18, maintains the plug and socket connection
19.
[00171 The frustoconical members 12 and 14 have tapered exterior surfaces 32
and
34 as best shown by tapered exterior surface 34 in Figure 2. In this example
exterior
surfaces 32 and 34 may have a morse taper. Tapered exterior surface 32 extends
between
bevelled peripheral portion 24 of inner end 16 and outer end 28. Tapered
exterior surface
34 extends between bevelled peripheral portion 26 of inner end 18 and outer
end 30.
Surface 32 is straight in the direction extending from bevelled peripheral
portion 24 to
outer end 28, and surface 34 is straight in the direction extending from
bevelled
peripheral portion 26 to outer end 30. The surfaces 32 and 34 may thus be
described as
having a straight taper. The tapered exterior surfaces 32 and 34 have the
shape of a partial
cone.
[00181 The frustoconical members 12 and 14 include longitudinally extending
central
passageways 36 and 38 for receiving the cords 11 and 13. Passageways 36 and 38
are
generally circular in cross-section, or put another way, partially
cylindrical, and are
shaped to receive the cords 11 and 13, respectively, shown in Figure 1. They
have a
diameter equal to or slightly smaller than the cord in this example.
Passageways 36 and
38 extend along and align with central axis 40 of the frustoconical members,
as shown in
Figure 2. Passageway 36 extends from inner end 16 to outer end 28 and
passageway 38
extends from inner end 18 to outer end 30.
[00191 The fustoconical members 12 and 14 include longitudinal channels 42 and
44
configured for readily guiding the cords 11 and 13 to central passageways 36
and 38.
Channel 42 extends from inner end 16 to outer end 28 and channel 44 extends
from inner
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end 18 to outer end 30. In this preferred embodiment, the channels are
quadrant-shaped in
cross-section, as shown in Figures 2 and 3 for channel 44.
[00201 The channels 42 and 44 include outer regions or outer openings, as
shown by
outer opening 45 in Figures 2 and 3. The outer openings are much larger than
the cross-
sectional diameters of cords 13 and 15 and are larger than the cross-sectional
diameter of
the central passageways. Channels 42 and 44 include inner regions or inner
openings, as
shown by inner opening 47 in Figures 2 and 3, which are adjacent to the
central
passageways. The inner openings are smaller than the cross-sectional diameters
of the
cord 13 and 15 and smaller than the cross-sectional diameter of the central
passageways.
The channels render the passageways more exposed for receiving the cords.
100211 Frustoconical member 12 has a pair of spaced-apart sides 46 and 48,
each of
which extends from tapered exterior surface 32 to central passageway 36.
Likewise
fructoconical member 14 has a pair of spaced-apart sides 50 and 52 that extend
from
tapered exterior surface 34 to central passageway 38. Sides 46, 48, 50 and 52
are
generally triangular in shape in this example as seen in Figure 1. Sides 46,
48, 50 and 52
are adjacent to and face channels 42 and 44, respectively. Sides 46 and 50 are
angularly
spaced-apart from sides 48 and 52, respectively, by an angle 0 in the
preferred range of
90 to 120 degrees. In this example the angle 0 is 90 degrees, as shown in
Figures 2 and 3
for sides 50 and 52. Sides 46 and 48, and 50 and 52 are thus configured for
readily
guiding the cords into the central passageways 36 and 38 since they taper
towards the
passageways.
100221 The sides and central passageways of the frustoconical members are so
configured to form protruding portions 54 and 56 of the frustoconical members
adjacent
to both the sides and passageways, as shown in Figure 3.
100231 The plug harness 10 includes a pair of elastic connecting bands or
members
58 and 60. The connecting members 58 and 60 are preferably round in cross-
section, as
shown in Figure 3. The connecting members 58 and 60 extend from and are
disposed
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between the bevelled peripheral portions 24 and 26 of the frustoconical
members 12 and
14. Advantageously, the connection members 58 and 60 as a result are partially
disposed
outwards and away from the frustoconical members. Thus, the bevelled
peripheral
portions 24 and 26 facilitate outward stretching of the connecting members 58
and 60 that
may occur, for example, from a plug and socket which large than the plug 15
and socket
17 shown in Figure 1.
[0024] The manner in which the plug harness 10 is preferably attached to the
plug
and socket connection 15 will now be described. Inner end 18 of the
frustoconical
member 14 is positioned to abut shoulder 22 of the socket 17, in this example.
Next, sides
50 and 52 of frustoconical member 14 direct and guide cord 11 as it is pushed
by a user's
fingers towards passageway 38 which, advantageously, enables the user to
perform this
act without much attention or focus. As the cord 11 is pressed against the
sides 50 and 52
by the user, the sides 50 and 52 are in turn caused to resiliently move
outwards relative to
one another. This in turn causes inner opening 47 to enlarge as to allow the
cord 11 to
pass therethrough and snap in place within the central passageway 38. With the
cord 11
disposed within passageway 38, the force applied to the sides 50 and 52 that
otherwise
caused the sides to bias outwards is reduced or eliminated, enabling the sides
to return to
their normal, unbiased positions. This in turn causes inner opening 47 to
return to its
normal unbiased size shown in Figures 2 and 3 once more. Portions 54 and 56 of
the
frustoconical member 14 may abut against and frictionally engage the cord 11
so as to
retain the cord within the passageway and inhibit the cord 11 from being
removed
therefrom.
[00251 With the inner end 18 of the frustoconical member 14 abutting shoulder
22 of
the socket 17, the user may now grab onto frustoconical member 12 and pull it
away
from frustroconical member 14. This in turn causes connecting members 58 and
60 to
stretch and expand in length. The user so stretches the plug harness as to
pull
frustoconical member 14 over the plug 15 such that inner end 16 of the
frustoconical
member 14 abuts and resiliently biases against shoulder 20 of plug 15. The
user may then
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snap frustoconical member 14 onto electrical cord 13 in a like manner as
described above
for frustoconical member 12 and cord 11.
[00261 With the cords 11 and 13 so held in place by the frustoconical members,
the
connecting members 58 and 60 continue to be in a stretched state. Inner ends
16 and 18
5 thus continue to abut with and resilient bias against, or squeeze together,
shoulders 20
and 22 of the plug and socket. This ensures that the plug and socket
connection 19 is
maintained. Put another way, this stretching of the frustoconical members 12
and 14
around connection 19 results in the device acting as a harness, retaining the
plug and
socket connection 19 together by applying pressure on the outside ends or
shoulders 27
10 and 29 of the plug 31 and socket 33, respectively. Advantageously this
harnessing is
achieved without pulling on the electrical cords 11 and 13 themselves.
[00271 The attachment of the plug harness 10 to cords 11 and 13 and around
connection 19 may be achieved in a matter of mere seconds. Attachment time is
even
further reduced when one is able to leave the plug harness 10 attached to one
of the cords,
usually the extension cord when the plug and socket are disconnected.
[00281 Many further advantages result from the structure of the plug harness
10 as
herein described. For example, the structure of the present invention, with
its quadrant-
shaped channel, allows electrical cords to more readily and easily be guided
to and
received in the frustoconical members of the plug harness. The channels 42 and
44 so
shaped conveniently allow the user to snap the device onto the electrical
cords. Because
outer openings 45 are larger than the cross-sectional diameters of the cords
and inner
openings 47 are smaller than the cross-sectional diameters of the cords, the
sides of
frustoconical members thus are shaped to both readily receive and direct the
cords
through the outer openings and selectively enable the cords to snap past the
inner
openings and into the passageways as desired, with the portions of the
frustoconical
members surrounding the inner openings further functioning to ensure that the
cords
remain in place. The channels 42 and 44 and surrounding portions of the
frustoconical
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members thus provide a synergy of enabling the plug harness to both readily
receive and
also readily attach to electrical cords.
[00291 The plug harness is a useful tool for people who use electrical
extension cords
regularly. Connection retaining pressure is applied to shoulders 20 and 22 of
plug 15 and
socket 17 so that there is no stress on the electrical cords 11 and 13. The
plug harness 10
does not require any tools to apply it and is quickly applied by hand to
harness, deflect
and maintain the electrical plug and socket connection 19 when the cords 11
and 13 are
pulled or dragged in either direction. It may easily be applied in seconds.
The plug
harness will harness an extra-large plug and socket connection like the
replacement
variety.
[00301 With its round, streamlined connecting members 58 and 60 and the
compact
nature and frustoconical members 12 and 14, the plug harness 10 provides the
advantage
of smoothly deflecting the plug and socket connection 19 around or over
corners and
snags when the cords 11 and 13 are dragged or pulled such as when operating
power
tools, while effectively retaining the electrical plug and socket connection
19. Plugs
getting caught or snagged can be extremely dangerous and damaging, for example
when
operating a skill saw, snagging can cause the blade to twist in the cut and
the saw to jump
and travel dangerously out of control. This can result in serious personal
injury and
expensive material damage. Because the connecting members 58 and 60 are round
in
cross-section, the cooling of the connecting members is more uniform, ensuring
that there
is better molecular bonding within the connecting members, ensuring that the
elastic
properties of the members are more uniform and thus stronger, more durable and
long-
lasting.
[00311 The device preferably has only two connecting members 58 and 60. This
provides the important advantage of allowing the device to be molded more
easily. It also
reduces parts.
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[0032] Because the plug harness 10 is made of an elastic, flexible material,
with no
rigid parts to break or slide when impacted or stepped on, the plug harness
has the ability
to both stretch and absorb shock. Put another way, the plug harness is
configured to be
non-slip when stepped on and absorbs shock when kicked. Thus, the user is less
likely to
trip on the plug harness or trip on the attached cords. Also, the resilience
of the plug
harness means that the plug harness does not distort or misshape conductor
cords by
crimping, wedging, bending or pressure.
[0033] Figures 4 to 9 show a plug harness 10.1 according to a further
embodiment.
Like parts have like numbers and function as the first embodiment above with
the
addition of ".1". The plug harness 10.1 shown in Figures 4 to 9 is
substantially similar to
that shown in Figures 1 to 3. However harness 10.1 has exterior openings 62
and 63 and
ribs 64 and 65 best shown in Figure 4 and recesses 66 and 68 and 70 and 72
best shown
in Figures 6 and 9.
[0034] Referring first to Figure 4, plug harness 10.1 includes a plurality of
openings
62 and 63 disposed along tapered exterior surfaces 32.1 and 34.1 of the plug
harness.
Openings 62 and 63 extend inwards from the surfaces 32.1 and 34.1 and are
configured
to promote uniform cooling of the plug harness after it is molded and inhibits
deformity/bulging that may otherwise arise. Ribs 64 and 65 are interposed
between
openings 62 and 63 to increase and maintain the structural integrity of the
frustoconical
members having such openings.
[0035] Referring to Figures 6 and 9, frustoconical member 12.1 has a pair of
spaced-
apart opposed recesses 66 and 68 located between its inner end 16.1 and outer
end 28.1.
Recesses 66 and 68 are in communication with passageway 36.1 and at least
partially
extend through sides 46.1 and 48.1 of the member 12.1, as shown in Figure 6.
Each of the
recesses 66 and 68 is in the shape of a triangular prism in this example.
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[0036] Frustoconical member 12.1 includes a pair of spaced-apart inner walls
76 and
78 adjacent to respective ones of the recesses 66 and 68. As best shown in
Figure 9, the
walls 76 and 78 are in communication with and extend tangential to passageway
36.1.
[0037] Referring to Figure 6, recesses 70 and 72 and inner walls 80 and 82 of
frustoconical member 14.1 are substantially the same as those for
frustoconical member
12.1 and therefore will not be described further.
[0038] Recesses 66, 68, 70 and 72 are advantageously shaped and positioned to
facilitate insertion of an initial portion of a cord into passageways 36.1 and
38.1. The
initial portion of the cord may be pushed through the recesses and into the
passageways
via the application of a user's thumb applying force against the cord.
Subsequent portions
of the cord are caused to engage the passageways 36.1 and 38.1 at a non-
perpendicular
angle. This allows the cord to be incrementally inserted within the
passageways with a
fraction of the force otherwise required to insert the cord within the
passageway all at
once. Recesses 66, 68, 70 and 72 thus thereby act to further facilitate the
insertion of the
cords into the passageways 36.1 and 38.1. The recesses as herein described
thus further
enhance the usability of the device, acting to make it even easier to apply
the plug
harness to the cords.
[0039] According to one example of plug harness 10.1, connecting members 58.1
and
60.1 each have a diameter of 0.143 inches. The distance between inner ends
16.1 and
18.1 is 2.25 inches. Inner ends 16.1 and 18.1 each have a diameter of 1.313
inches. The
passageways 36.1 and 38.1 each have a diameter of 0.3125 inches. The distance
between
outer ends 28.1 and 30.1 is 5.5 inches.
[0040] Many further variations are possible within the scope of the invention.
For
example the configuration of the frustoconical members 12 and 14 can vary. For
example, the frustoconical members 12 and 14 may include further reliefs or a
skeletal
shape to save on elastic material or vary strength. Also it should be known
that either
frustoconical member 12 or frustoconical member 14 could be replaced by an
attached
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socket or vary as long as one frustoconical member is the same as
frustoconical member
12 or frustoconical member 14.
[0041] It will be understood by someone skilled in the art that many of the
details
provided above are by way of example only and are not intended to limit the
scope of the
invention which is to be determined with reference to the following claims.
