Note: Descriptions are shown in the official language in which they were submitted.
7~1L3~
This invention relates to a plastic plug support
bracket which supports an electrical plug which is detachably
mounted in a receptacle therefor on a panel of a vehicular
body, such as the forwardmost panel of a trailer of a
tractor-trailer type vehicle.
The electrical system of the trailer of a tractor-
trailer vehicle is detachably connected to that of the
tractor by means of one or more plug and electrical re-
ceptacle assemblies. The receptacle member of the assembly
is usually mounted on the front panel of the trailer and/or
the rear panel of the tractor and the plug member is fastened
to the ends of a cable which leads from the tractor to lights
and the like on the trailer. The receptacle member has a
cylindrical body enclosing a plurality of prongs which are
inserted in corresponding electrically conductive bores
in the plug each secured to a wire of the cable. A flange
is provided about the cylindrical body for fastening the
receptacle to the trailer. Since the plug is a relatively
large a~d heavy metallic or molded cylindrical member, it
must be supported externally of the receptacle to prevent it
from being shaken loose from the receptacle while the vehicle
is being operated.
Metal plug support brackets for supporting the electri-
cal plug detachably mounted in the receptacle are known in the
prior art. ~owever, these metal plug support brackets have
proven to be disadvantageous for several reasons. First, the
metal brackets are extremely brittle and are easily broken
when subjected to the vibration transmitted to them from the
operation of the vehicle on which they are mounted This
1~47~
breaking is even more pronounced when the bracket is used
in a low temperature environment of,for example, 32F or
lower. As the vehicles on which these brackets are mounted
sometimes travel in low temperature regions, they are often
subjected to these low temperatures and therefore frequently
break and cause down-time for the vehicle for repairs. Second-
ly, in the prior art metal plug support brackets, the plug
supporting portion is freely pivotally connected to the base
portion so that when the plug is disconnected from the re~
ceptacle, the plug supporting portion is continually, again
by reason of the vibration to which it is subjected by the
vehicle in operation, pivoting freely from the base portion
and slapping or knocking against the panel of the vehicle which,
of course, is a nuisance to the vehicle driver. Furthermore,
this continual slapping or knocking is a further cause of
the above-noted hreaking problem of the prior art metal
bracket. Thirdly, because the prior art plug support bracket
is made of metal, the interior of the semi-circular band of
the plug supporting portion must be machined afker it is made
so that its shape will conform to the axial extending portion
of the lower semi-circular half of the electrical plug which
it was made to support. This cumbersome machining increases
the cost of such brackets.
In accordance with this invention, a substantially rigid
plastic plug support bracket which is resistant to damage by
impact, impervious to gas, oil, grease, ultraviolet rays and
ozone, and will remain stable at temperatures of from -75F
to ~400F is provided. By providing a substantially plastic
plug support bracket as in the invention, the bracket is not
easily broken and is, in fact, substantially impact-proof
even at low temperatures down to -75F or lower.
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13~
Also, by providing a substantially rigid plastic plug
support bracket as in the invention, if the plug is made by
injection molding or other known processes, the interior of
the semi-circular band of the plug supporting portion is shaped
to conform to the axially extending portion of the semi-circular
lower half of an electrical plug which is circular in cross-
section and does not have to be subsequently machined to ob-
tain the desired shape. Therefore, with the invention this
otherwise cumbersome machining is not needed and should there-
fore reduce the unit production cost of the plug supportbracket.
Also, in the invention, the transverse dimension of
one end of the arm is substantially equal to the space be-
tween the pivot brackets so that the plug supportlng portion
of the bracket is frictionally held against free pivotal
movement relative to the base portion by the frictional in-
terface between the end of the arm and the pivot brackets.
In the advantageous embodiment to be described, the end of
the arm is substantially rectangular in cross-section to pro-
vide a face on each side of it which frictionally abuts a faceof a respective one of the pair of pivot brackets to frictional-
ly hold the plug supporting bracket against free pivotal move-
ment relative to the base portion. As a result of this aspect
of the invention, the plug supporting portion is not freely
pivotable relative to the base portion and therefore does not
slap or knock against the panel of the vehicular body to which
it is attached so that the nuisance caused to the operator of
the vehicle by such slapping or knocking as well as the breakage
of the bracket which may be caused by it is eliminated.
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It is an object of this invention to provide a
plastic plug support bracket which is substantially impact-
proof and cannot he broken or rendered in any way inoperative
when mounted on a vehicle when the vehicle is in normal
operation.
It is a further object of this invention to provide a
plastic plug support bracket which is impervious to gas, oil,
and grease.
It is a further object of this invention to provide a
plastic plug support bracket which is impervious to ultra-
violet rays and ozone.
It is a further object of this invention to provide a
plastic plug support bracket which will remain stable at
temperatures from -75F to +400F.
It is a further object of this invention to provide a
plastic plug support bracket which is not easily broken during
normal operation of the vehicle on which it is mounted.
It is a further object of this invention to provide a
plastic plug support bracket which is not easily borken during
normal operation of the vehicle on which it is mounted, par-
ticularly one which is not easily broken at temperatures down
to -75F.
It is a still further object of this invention to pro-
vide a plastic plug support bracket which does not require any
subsequent cumbersome machining of any portion thereof after
the bracket is completed.
It is still a further object of this invention to pro-
vide a plastic plug support bracket in which the plug support-
ing portion is not freely pivotable relative to the base
-- 4 --
~47138
portion thereof so that the plug supporting portion is there-
by prevented from slapping or knocking against the panel of
a vehicle on which the bracket is mounted.
Fig. 1 is a perspective view showing the forward panel
of the trailer of a tractor--trailer type vehicle.
Fig. 2 is a perspective view showing the panel of the
vehicle with the receptacle mounted thereon and the sub-
stantially rigid plastic plug support bracket connected to
the receptacle with the electrical plug mounted in the re-
ceptacle and the plug supporting portion of the bracket
supporting the plug.
Fig. 3 is a view similar to Fig. 2 but showing the
plug disconnected from the receptacle and the plug support-
ing portion of the substantially rigid plastic plug support
bracket out of its supporting position.
Fig. 4 is a side view, looking in the direction in
which the plug is inserted, of the substantially rigid plastic
plug support bracket mounted on a panel with the plug support-
- ing portion of the bracket in its supporting position.
Fig. 5 is a view taken along line 5-5 of Fig. 4.
In Fig. 1, is shown a tractor-trailer T. On the forward-
most panel P of the trailer of the vehicle are positioned a
plurality of electrical receptacles 10 which receive a re-
spective one of a corresponding number of electrical plugs 11.
The receptacles 10 and electrical plugs 11 received therein
are well-known in the prior art. The purpose of the connection
of the plug 11 into the receptacle 10 is to provlde power to
the trailer from the tractor for the lights or other power
equipment, such as a refrigeration unit, in the trailer.
~4713~
As shown in Fig. 3, each receptacle 10 includes a
plurality of male prongs 12. Each prong 12 is received
in a respective one of a plurality of openings 13 in the
plug 11 when the plug is connected into the receptacle.
To further lock the plug in the receptacle, the receptacle
has a longitudinal notch 14 cut into the upper portion of
the interior surface thereof. A key 15 is provided on the
exterior surface of the plug 11. The key 15 is shaped
complementary to the notch 14 so as to further assist in
locking and prevent rotation o the plug 11 in the receptacle
10. However, as is known in the prior art, by reason of the
vibration to which the plug 11 and receptacle 10 are sub-
jected by the operation of the vehicle on which they are
mounted, the plug 11 tends to move or walk out of the
receptacle 10 which, of course, results in a disconnection
of the power from the tractor to the trailer of the tractor-
trailer T. This cutoff of power to the trailer, of course,
results in unnecessary and sometimes expensive down-time
of any equipment, such as refrigeration units, in the
trailer.
To prevent this unnecessary disconnection of the plug
11 from the receptacle 10, the invention provides a sub-
stantially rigid plastic plug support bracket 20. The plug
support bracket 20 comprises a base portion 30 and a plug
supporting portion 40 which is pivotally connected to the
base portion 30.
The base portion 30 comprises a substantially V-shaped
base plate 31 with legs 34, 35 and a substantially semi-
circular upper edge 32 therebetween (Figure 4). The edge 32
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is shaped so that it may be positioned around the lower
half of the substantially circular plug receiving portion
of the receptacle 10. Each of the legs 34, 35 o the V-
shaped base plate 31 has an aperture 33 therein~ ~ bolt
or screw 50 is inserted through each aperture 33 to secure
it to the receptacle 10. As the receptacles of the prior
art are provided with holes to secure them to the panel of
the vehicle, it is desirable that the aperture 33 in each
leg 34, 35 be spaced identical to the holes in the prior
art receptacle so that the bolts or screws 50 can then be
used to mount both the receptacle 10 and plug support brac-
ket to the panel P of the vehicle as shown in Fig. 5.
The base portion 30 further includes, at the bottom
of the base plate 31, a pair of spaced parallel pivot brac-
kets 36. Each pivot bracket 36 extends from and is sub-
stantially perpendicular to the face 31a of base plate 31.
The plug supporting portion 40 of the substantially
rigid plastic plug support bracket 20 includes an elongated
arm 41 and a substantially semi-circular band 46. The band
46 is integrally connected, at the mid-point of its periphery,
to one end 42 of the arm 41. The interior sruface 46a of the
band 46 is shaped to conform to the lower semi-circular half
of the electrical plug 11. The length of arm 41 is such that
when member 40 is in its supporting position shown in Figures
4 and 5, the upper surface of plug 11 is pressed against the
inner surface of receptacle 10. In other words, the length
of arm 41 from the pivot point to the inner surface of member
46 along the longitudinal axis of arm 41 is slightly larger than
the distance between the pivot point and the botton of the plug
7~L31~3
in its normal inserted position where its axis coincides with
that of receptacle 10 so that the plug is pushed upwardly so
its axis is no longer parallel to the axis of the receptacle.
The other end 43 of the arm 41 is substantially rectangular
in cross-section, as shown in Figs. 2 through 4, to provide
a pair of faces 43a, 43b which frictionally abut the faces
36', 36'' of the pair of pivot brackets 36 (Figure 4). The
end 43 has a transverse dimension which is substantially
equal to the space d between the pair of pivot brackets 36.
By reason of the structural conformation of the end 43 of
the arm 41 relative to that of the pair of pivot brackets
36, the plug supporting portion 40 of the plug support
bracket 20 is held against free pivotal movement relative
to the base portion 30 by the frictional interface formed
between the faces 43a, 43b of the end 43 of the arm 41 and
the faces 36', 36'' of the pivot brackets 36. As the plug
supporting portion 40 of the plug support bracket 20 is not
reely pivotable relative to the base portion 30, it will
not slap or knock against the panel P when the plug support-
ing portion is not in use in supporting the plug 11. A
strenghening rib 44 extends from the base member 43 along
each side of arm 41 and semi-circular member 42.
The base portion 30 of the plug support bracket 20
also includes a spacer member 37 which extends from the
other face 31b of the base plate 31. The spacer member 37
may be substantially circular in cross-section and is pro~
vided to take up the space between the lower portion of
the base plate 31 and the panel P in the region below the
1~)47~38
receptacle 10. As the spacer member 37 is in abutment
with the portion of the panel P, it provides additional
support for the plug support bracket 20.
To provide the pivotal connection between the base
portion 30 and the plug supporting portion 40, an aperture
36a is provided in each of the pivot brackets 36 and an
aperture 43' is formed in the end 43 of the arm 41. A
pin 38 extends through these apertures so that the arm 41
may pivot about the a~is of the pin relative to the base
portion 30.
The operation of the invention will now be described.
When the operator of a vehicle desires to provide an electri-
cal connection from the tractor portion of the tractor-
trailer T to the trailer, he merely lifts up the cap lOa
closing the opening of the receptacle, and, by reason of
the alignment made by the key 15 on the plug 11 with the
notch 14 in the receptacle 10, forceably inserts the plug
11 into the receptacle 10. To prevent the plug 10 from
slipping or walking out of the receptacle 10, the operator
then moves the plug supporting portion of the plug support
bracket 20 from a lower position as in Fig. 3, up into
its position beneath the plug 11 into the plug supporting
position shown in Figs. 2, ~ and 5. In this position the
plug support bracket, with the interior surface 46a of
the semi-circular band 46 supportingly abutting an axial
portion of the lower half of the semi-circular surface of
the plug 11, provides additional support for the plug 11
in the receptacle 10 and prevents the plug from moving or
walking out of the receptacle. Also as noted above,
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additional support is also provided by the abutment of the
spacer member 37 with the portion of the panel P below the
receptacle 10 as shown in Figure 5.
When the operator desires to disconnect the plug 11
from the receptacle 10, he merely pulls the plug supporting
portion 40 of the plug support bracket 20 outwardly and
downwardly to pivot it about the axis of the pin 38 back to
a lower position such as the one shown in Fig. 3. The
operator then merely withdraws the plug 11 from the re-
ceptacle 10 at which time the closure cap 10a of the re-
ceptacle 10, by reason of its being spring biased to a
closed position, covers the receptacle 10 to prevent dirt or
other foreign matter from entering therein.
The plug support bracket 20 of this invention, may be
made by any plastic or thermo-plastic which is substantially
impact-proof, impervious to gas, oil, grease, ultraviolet
rays and ozone and will remain stable at temperatures from
-75F to ~400F. One example of such a plastic is the one
sold by General Electric Company under the tradename
"Valox", a moldable (polyethylene terephthalate)polyester.
It will, of course, occur to persons skilled in the art that
many other plastics or thermo-plastics having the above
characteristics are suitable for this invention.
The plug support bracket 20 of this invention is there-
fore virtually unbreakable at all normal operating -temperatures
to which the vehicle on which it is mounted would normally
be subjected. Furthermore, by reason of the frictional inter-
face in the pivotal connection between the plug supporting
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7138
portion and the base portion of the plug support bracket 20,
the plug supporting portion does not slap or knock against
the panel and therefore is not a nuisance to the operator
of the vehicle and will not cause breakage of the bracket.
Furthermore, when this bracket is made, the interior face
46a of the band 46 requires no further machining in order
to have it conform as closely as possible to the lower
periphery of the plug 11.
While the plug support bracket of this invention has
been described above in connection with the tractor-trailer
type vehicle, it will occur to persons skilled in the art
that the plug support bracket is useable i.n any environment
where the prior art plugs and receptacles have been used
and is particularly useful in environments where the prior
art plugs and receptacles are subjected for any reason to
substantial vibration. For example, these receptacles have
been mounted on the rear panel of the tractor of the
tractor-trailer vehicle and on other types of vehicles
such as refrigeration trucks, milk trucks, to provide
an electrical connection to them from a main power source
apart from the vehicle when the vehicle is otherwise in-
operative.
It is evident from the above description that, by
means of this invention, the deficiencies of the prior
art metal plug support bracket are overcome.
