Three prong swivel plug

A swivel plug is provided which has male and female plug portions which pivot 180.degree. with respect to one another about a common pivot axis between first and second positions. A plurality of male and female electrical contact pairs slidably engage one another and pivot about the common pivot axis. Male and female bodies, which receive the electrical contact pairs, also pivot with respect to one another about the common pivot axis. The male and female bodies and the male and female electrical contact pairs are arranged in a novel relationship to mutually retain one other for the pivotal movement. The swivel plug eliminates the need for an electrical cord between an adapter of a laptop computer and a wall receptacle which has a downwardly located ground receptacle or a wall receptacle which has an upwardly located ground receptacle. The swivel plug also enables plugging a computer adapter or a typical extension cord into a receptacle where there is a rigid space constraint.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a swivel plug and more particularly to a 
male and female plug which are interconnected for pivotal movement 
180.degree. with respect to one another, each plug employing a ground 
contact. 
2. Description of the Related Art 
Laptop and notebook computers employ an adapter which is sometimes referred 
to as a "brick" because of its brick-like size and appearance. An 
electrical cord extends from one end of the adapter to a plug which can be 
inserted into a receptacle in a side of the computer. At an opposite end 
of the adapter there is a recessed male three prong connector. A second 
electrical cord is supplied which has a three prong female plug at one end 
and a three prong male plug at an opposite end. The female plug of the 
second electrical cord is plugged into the recessed male plug of the 
adapter and the three prong male plug of the second electrical cord is 
typically plugged in a wall receptacle or a power strip. Power can then be 
supplied to the computer via the adapter. 
Laptop and notebook computers should be kept as compact and light as 
possible because of their intended portability. Elimination of the second 
cord would improve portability. Substitution of a compact and lightweight 
connector for the second electrical cord would be desirable for increasing 
portability. There are several requirements for such a connector. The 
connector must be capable of plugging the adapter into a down ground prong 
wall receptacle, an up ground prong wall receptacle, or a power strip. In 
all instances the connector must properly position the adapter with 
respect to the wall receptacle or the power strip. Unfortunately, the 
prior art does not provide such a connector. When a user travels to 
foreign countries he may be required to carry as many as three different 
types of second electrical cords because of the different types of wall 
receptacles. Elimination of these cords would significantly increase 
portability. 
SUMMARY OF THE INVENTION 
The present invention provides a three prong swivel plug which eliminates 
the requirement of the second electrical cord presently supplied with a 
laptop or notebook computer. The swivel plug has a female plug which plugs 
into the adapter and a three prong male plug which plugs into a 
receptacle. The male and female plugs of the swivel plug can rotate 
180.degree. with respect to one another. When the three prong male plug of 
the swivel plug is plugged into a wall receptacle the adapter can be hung 
in a downward position regardless of the type of wall receptacle. For 
instance, if the wall receptacle has a downwardly located ground contact 
the male and female plugs of the swivel plug are rotated so that they are 
positioned 90.degree. with respect to one another with the ground prong of 
the male plug downwardly positioned. With this arrangement the adapter is 
positioned downwardly from the wall receptacle. If the wall receptacle has 
an upwardly located ground contact then the male and female plugs are 
rotated 180.degree. with respect to one another so that they are 
positioned 90.degree. with respect to one another with the ground prong of 
the male plug positioned upwardly. With this arrangement the adapter still 
hangs downwardly with respect to the wall receptacle. Further, the swivel 
plug enables the adapter to be plugged into a power strip even though 
there are other cords plugged in the power strip. The adapter can be 
plugged into the power strip with the adapter positioned in an upright 
position or with the adapter positioned horizontally with the plane of the 
power strip. 
The swivel plug is unique in that the male and female plugs pivot with 
respect to one another about a pivot axis which is generally perpendicular 
to the longitudinal axes of the male and female plugs. This requires that 
both the plug bodies and the electrical contacts retained by the bodies 
pivot about a common pivot axis. Stops are provided for limiting pivotal 
movement to 180.degree. and slidable electrical connection is maintained 
between the male and female contacts throughout the pivotal movement. The 
three prong swivel plug eliminates the need of the second electrical cord 
employed by the prior art thereby reducing bulk and weight. When a person 
travels to foreign countries he or she simply carries three of the three 
prong swivel plugs instead of carrying three second electrical cords. 
While the plug was primarily envisioned for use with a laptop or notebook 
computer it has other uses such as increasing the versatility of a 
standard extension cord. As an example, when there is little space near a 
wall receptacle a standard extension cord can extend straight down when 
plugged into the wall receptacle via the swivel plug. Without the swivel 
plug the standard extension cord would make a large bend before extending 
downwardly. Another example is when it is desirable for a standard 
extension cord to extend horizontal from a power strip. The cord can 
extend in either direction from a power strip by orienting the swivel plug 
in a desired 90.degree. direction. In both of these examples there is less 
likelihood of an unwanted disconnection since pulling forces perpendicular 
to the wall receptacle or the power strip receptacle are minimized. 
An object of the present invention is to provide a swivel plug which 
eliminates the necessity of a second electrical cord for plugging an 
adapter of a laptop or notebook computer into a receptacle. 
Another object is to provide a swivel plug which enables an adapter of a 
laptop or notebook computer to be plugged into a wail receptacle and hang 
directly downwardly regardless of whether the ground prong of the swivel 
plug is up or down. 
A further object is to provide a swivel plug which enables an adapter of a 
laptop or notebook computer to extend vertical or horizontal after being 
plugged into a power strip via the swivel plug. 
Still another object is to provide a swivel plug which enables plugging a 
standard electrical cord into a wall receptacle where there is a small 
amount of space from the wall. 
Still a further object is to provide a swivel plug which orients a standard 
electrical cord straight up or straight out from a power strip. 
Other objects and many of the attendant advantages of the invention will 
become apparent upon reading the following description taken together with 
the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings wherein like reference numerals designate 
like or similar parts throughout the several views there is illustrated in 
FIG. 1 a prior art arrangement of a notebook computer 20 being supplied 
power by an adapter 22 which is connected to a wall receptacle 24. The 
adapter 22 is sometimes referred to as a "brick" because of its brick-like 
size and appearance. A typical power supply includes an electrical cord 26 
which is permanently connected to the adapter at one end 28 and which is 
plugged into the computer 20 at the other end by a plug 30. A second 
electrical cord 32 has a female plug 33 which is connected to a recessed 
male connector in the opposite end 34 of the adapter and a male plug 36 
which is plugged into a power supply, such as the wall receptacle 24. This 
prior art arrangement requires the user to carry the second electrical 
cord 32 which adds additional bulk and weight to his luggage. If the user 
is traveling in foreign countries he may be required to carry up to three 
additional electrical cords 32 which are fashioned at their ends for 
plugging into the foreign power supplies. It would be desirable to 
eliminate the second electrical cord so as to reduce bulk and weight. 
In FIG. 2 the present invention eliminates the prior art second electrical 
cord 32 by providing a swivel connector 40 which has a female plug 42 
which plugs into the end of the adapter 22 and a male plug 44 which plugs 
into the wall receptacle 24. When the swivel plug is plugged into a wall 
receptacle which has a downwardly located ground contact, as shown in FIG. 
2, the swivel connect 40 allows the adapter to hang downwardly. When the 
swivel plug is plugged into a wall receptacle which has an upwardly 
located ground contact, as shown in FIG. 3, the swivel plug is rotated 
180.degree. so that the adapter still hangs downwardly. When the swivel 
plug is used in the manner shown in FIGS. 2 and 3, the friction between 
the connecting components of the female plug 42 and the recessed male 
connection of the adapter is sufficient to support the weight of the 
adapter in the downward position as shown in the figures. 
In FIGS. 4 and 5 the invention is shown plugged into a power strip 46. The 
power strip has a plurality of receptacles where all of the receptacles 48 
may be in use for extension cords except one, as shown in FIG. 4. This 
leaves insufficient space to position the adapter between adjacent plugs. 
The swivel plug may be employed to plug the adapter 22 into the power 
strip so that the adapter is positioned out of the way of adjacent plugs. 
In FIG. 4 the swivel plug plugs the adapter into the power strip at a 
90.degree. angle so that the adapter is positioned horizontally and in 
FIG. 5 the swivel connector connects the adapter 22 to the power strip in 
a straight-up vertical position. Accordingly, the present swivel plug 
emulates the prior art second power cord without the long cord. 
FIGS. 6, 7 and 8 are enlarged illustrations of the swivel connector in its 
three major positions. FIG. 6 shows the swivel connector with the male and 
female plugs in a first 90.degree. position, FIG. 7 shows the male and 
female plugs in an aligned vertical intermediate position and FIG. 8 shows 
the male and female plugs in a second 90.degree. position. The male and 
female plugs have been rotated a total of 180.degree. between the first 
and second positions shown in FIGS. 6 and 8. As will be explained 
hereinafter, the plugs are stopped at the first and second positions by 
surfaces of the plug bodies which engage one another as shown in FIGS. 6 
and 8. 
In FIG. 9 the swivel plug 40 is shown with the female plug 42 rotated 
90.degree. with respect to the male plug 44. The plugs 42 and 44 are 
rotatable 180.degree. with respect to one another about a pivot axis 50. 
The swivel plug 40 includes a first body 52 and a second body 54. The 
first body 52 has first and second body portions 56 and 58, the first body 
portion 56 being received within the second body portion 58. The second 
body 54 has first and second body portions 60 and 62, these two portions 
making engagement with one another along a plane 64. Screws 66 and 68 may 
be threaded into the components for retaining the first and second body 
portions of the first and second bodies 52 and 54. First, second and third 
electrical male contacts, which will be described in more detail 
hereinafter, are retained within the first body 52 between the first and 
second portions 56 and 58 and extend therefrom to provide first, second 
and third prongs 70, 72 and 74 with the third prong 74 being a ground 
prong. Female electrical contacts 76, 78 and 80, which will be described 
in more detail hereinafter, are retained within the second body 54 by the 
first and second body portions 60 and 62. The male electrical contacts, 
which provide the prongs 70, 72 and 74, define the extent of a volume 
which has a triangular cross-section within the second body portion 58. 
The first body portion 56 has a mating triangular body portion which is 
received within the second body portion 58 and which retain the male 
electrical connectors. This will become more clear hereinafter. 
FIG. 10 illustrates an exploded top isometric view of the swivel plug. The 
first and second portions 56 and 58 of the first body 52 have axial end 
portions 82 and 84 which are intersected by the pivotal axis 50 as seen in 
FIG. 9. The axial end portion 84 is divided into a pair of spaced apart 
first and second axial end portions 84a and 84b which snugly receive the 
axial end portion 82. The first and second body portions 60 and 62 of the 
second body 54 have axial end portions 86 and 88 which are intersected by 
the pivotal axis 50 as shown in FIG. 9. The axial end portion 86 includes 
a pair of spaced apart axial portions 86a and 86b and the axial end 
portion 88 includes a pair of axial end portions 88a and 88b, the axial 
end portions 86 and 88, when combined together, snugly receiving the axial 
end portions 82 and 84 of the first body 52. The axial end portions 86a, 
86b, 88a and 88b may be provided with outwardly facing rounded surfaces 
which are textured or roughened at 90 so that frictional engagement is 
increased between these surfaces and arcuate surfaces 92 and 93 on the 
second body portion 58 of the first body (see also FIG. 11). Male 
electrical contacts 92, 94 and mentioned hereinabove, provide the prongs 
70, 72 and 74 as shown in FIG. 10. The male electrical contacts 92, 94 and 
96 have axial end portions 98, 100 and 102 which are intersected by the 
pivotal axis 50, as seen in FIG. 9, the axial end portions 98 and 100 
angling downwardly from middle portions 104 and 106 and the axial end 
portion 102 angling upwardly from a middle portion 108. 
The second body portion 58 of the second body 52 is provided with a pair of 
inwardly extending spaced apart elongated slots 109 and 110 and the axial 
end portion 84 of the second body portion is provided with angled slots 
111 and 112 for receiving the middle portions 104 and 106 of the male 
connectors 92 and 94. The second body portion 58 is further provided with 
elongated arcuate recesses 114 and 116 for receiving the middle portion 
108 of the male connector 96. When generally triangular shaped first body 
portion 56 is received within the second body portion 58 the male 
electrical contacts 92, 94 and 96 are held firmly in place with male prong 
portions 70, 72 and 74 extending therefrom, as illustrated in FIG. 9. The 
axial end portion 82 of the first body portion 56 is tapered so as to 
allow axial end portions 84a and 84b to provide the angled slots 111 and 
112. This arrangement also allows outside surfaces of the axial end 
portions 84a and 84b to slidably engage inside surfaces of the axial 
portions 88a and 88b and 86a and 86b of the first and second body portions 
60 and 62 of the second body 54. The axial end portions 82 and 84 of the 
first and second body portions 56 and 58 of the first body 52 are provided 
with vertically oriented slots 118 and 120 for receiving the axial end 
portion 102 of the ground male connector 96 so that it can transition to 
the pivotal axis 50. 
The female electrical contacts 76, 78 and 80, shown in FIGS. 10 and 11, 
have axial end portions 128, 130 and 132 which are intersected by the 
pivotal axis 50, shown in FIG. 9. The first and second body portions 60 
and 62 of the second body 54 are provided with elongated slots for 
receiving the first, second and third female contacts 76, 78 and 80. As 
seen in FIG. 10, the second body portion 62 is provided with elongated 
slots 134, 136 and 138 and, as seen in FIG. 11, the first body portion 60 
is provided with matching elongated slots 140, 142 and 144 so that when 
the body portions 60 and 62 are mated the female electrical contacts 76, 
78 and 80 are tightly retained by the bodies within the elongated slots. 
The axial end portions 128 and 130 of the first and second female 
electrical contacts 76 and 78 angle slightly upwardly while the axial end 
portion 132 of the female electrical contact 80 angles slightly downwardly 
toward the pivotal axis 50 (see FIG. 9). This is because the first and 
second female electrical contacts 76 and 78 are on the same plane while 
the third female electrical contact 80, which is ground contact, is above 
that plane as seen in FIG. 10. The second and first body portions 62 and 
60 are provided with central slots 146 and 148, as seen in FIGS. 10 and 
11, respectively, so that the axial end portion 132 of the female ground 
connector can transition to the pivotal axis 50, shown in FIG. 9. 
It is necessary for the axial end portions 98, 100 and 102 of the male 
electrical connectors to make electrical connection with the axial end 
portions 128, 130 and 132 of the female connectors in such a manner that 
they can slidably rotate about the pivotal axis 50 when the bodies 52 and 
54 are rotated about the pivotal axis 50. In the preferred embodiment, 
dimples are provided on the axial end portions of the male and female 
electrical connectors along the pivotal axis 50, the dimples protruding 
from a side of a respective axial end portion and providing a recess on an 
opposite side of the axial end portion. The axial end portions 98, 100 and 
102 of the male electrical connectors may be provided with similar dimples 
150, 152 and 154 which are received within recesses of dimples 156, 158 
and 160 on the axial end portions 128, 130 and 132 of the female 
connectors. This can be clearly seen from FIGS. 12 and 13. The pivotal 
axis 50 intersects substantially the center of each dimple. 
In order to receive and retain the male and female electrical contacts in 
slidable contact with one another along the pivotal axis 50, the 
protrusions of the dimples 156 and 158 are received within notches on the 
inside surfaces of the axial portions 86a, 86b, 88a and 88b of the first 
and second body portions 60 and 62 of the second body 54. The axial 
portions 86a and 86b, as seen in FIG. 11, have notches 164 and 166, and 
axial portions 88a and 88b, as shown in FIG. 10, have notches 168 and 170 
so that when the first and second body portions 60 and 62 of the second 
body 54 are mated together the notches are opposite one another so as to 
tightly retain the protrusions of the dimples 156 and 158. The axial end 
portions 84a and 84b are provided with angled slots one of which is shown 
at 172 in FIG. 10 for axial end portion 84a, for receiving the angled 
axial end portions 98 and 100 so that the dimples 150 and 152 are 
positioned for slidable movement about the pivotal axis 50 within the 
recesses of the dimples 156 and 158 in the axial end portions of the 
female connectors. In the same manner, the second portion 58 of the first 
body is provided with a notch 176, as seen in FIG. 10, for receiving the 
protrusion of the dimple 154 on the axial end portion 102 of the male 
connector 96. 
When the male and female electrical connectors are placed in the recesses 
in the body portions of the first and second body portions 52 and 54 and 
the first body 56 is retained within the second portion 58 by the bolts 68 
and the first and second body portions 60 and 62 of the second body 54 are 
mated together and secured by the screws 66, the first and second bodies 
52 and 54 and the male and female electrical connectors are rotatable 
about the pivotal axis 50. It is important to note that the axial end 
portions 84a and 84b of the second body portion 58, the axial end portion 
82 of the first body 56, the axial end portions 86a and 86b of the first 
body portion 60, the axial end portions 88a and 88b of the second body 
portion 62, the dimples 150, 152, 154 of the male connectors and the 
dimples 156, 158 and 160 of the female connectors all cooperate with one 
another when the components are put together to accomplish two functions: 
(1) retain the bodies 52 and 54 for rotation about the pivotal axis 50 and 
(2) maintain electrical contact of the axial end portions of the male 
electrical connectors and the axial end portions of the female electrical 
connectors as they rotate about the pivotal axis 50. It should be noted 
that when the dimples 150 and 152 of the male electrical connectors mate 
with the dimples 156 and 158 of the female electrical connectors within 
the notches 164, 166, 168 and 170 of the first and second body portions 60 
and 62 that the body portions 52 and 54 are locked together for the 
desired pivotal action and the aforementioned male and female electrical 
connectors are locked together for rotation about the pivotal axis 50. As 
stated hereinabove, the dimple 154 of the male electrical connector, which 
is ground, recesses within the recess of the dimple 160 of the ground 
female electrical connector 80 and is retained in slidable engagement with 
respect thereto within the notch 176. It should be understood that rivets 
could be employed instead of dimples to provide a protrusion within the 
aforementioned notches within the body portions 56, 58, 60 and 62 of the 
first and second bodies 52 and 54. If rivets are employed the heads of the 
rivets will protrude outwardly to recess within the aforementioned notches 
164, 166, 168 and 170. 
In FIG. 11 there are shown exterior slanted surfaces 184 and 186 on the 
body portions 58 and 62 which engage one another and stop pivotal action 
of the first and second bodies 52 and 54 in the first 90.degree. position 
shown in FIG. 6. In FIG. 10 there are shown exterior slanted surfaces 178 
and 180 on the portion 58 and exterior slanted surface 182 on the body 
portion 60 which engage one another and stop pivotal action of the bodies 
52 and 54 in the second 90.degree. position as shown in FIG. 8. Frictional 
engagement between the textured surfaces 90 of the portions 60 and 62 and 
the exterior portions 92 and 94 of the second body portion 58 retain any 
angular position of the bodies 52 and 54 between the extreme 90.degree. 
positions shown in FIGS. 6 and 8, such as the intermediate position shown 
in FIG. 7. 
The three prong swivel adapter has provided a unique combination for 
maintaining connection between the portions of the first and second bodies 
52 and 54 and the male and female electrical connectors by a novel 
combination and cooperation between these components. It is to be 
understood that the body portions 56, 58, 60 and 62 of the first and 
second bodies 52 and 54 are made of an insulation material such as 
plastic. The male and female electrical connectors may be made of a 
suitable conductive material such as brass or copper. 
Obviously, other embodiments and modifications of the invention will occur 
to those of ordinary skill in the art in view of these teachings. 
Therefore, the invention is to be limited only by the following claims 
which include all such embodiments and modifications when viewed in 
conjunction with the above specifications and accompanying drawings.