BACKGROUND OF THE INVENTION
Field of the Invention:
[0001] The present invention relates to an AC power plug assembly adapted for various foreign
countries, particularly to an AC power plug assembly for electric devices such as
AC power adapter, AC/DC converter, battery charger, and so on which are integrally
combined with an AC plug.
Description of the Background Art:
[0002] AC plugs currently used over the world have not yet been standardized to a single
shape. Accordingly, it is required to use a specially made plug adapter or exchange
plug shape when electric devices commonly used in Japan are used or sold in various
foreign countries especially in Europe. On the other hand, AC plug integrally formed
electric devices such as battery chargers have been required to reconstruct their
plug element so as to fit the plug shape with that of plug socket used in their destination.
As shown in Fig. 4, in a typical conventional manner, a pair of pins or blades 2,
2 has been integrally disposed in a housing 1 of electric device by a molding process.
In detail, a pair of plug pins 2, 2 should be previously inserted in a metal mold
for molding the housing 1. The shape, dimension, and angle of the pair of plug pins
2, 2 may vary in accordance with the plug socket used in destination. This means the
manufacturing process of such insert-molded plug will complicate. That is, the cost
of the electric device having such insert-molded plug will rise.
SUMMARY OF THE INVENTION
[0003] Therefore, it is a primary object of the present invention to provide an improved
AC plug assembly which permits a pair of plug pins to be easily assembled within a
housing of electric device.
[0004] Another object of the present invention is to provide an improved AC plug assembly
which can be easily fit to any shapes of plug sockets used over the world.
[0005] Further object of the present invention is to provide an improved AC plug assembly
which has a sufficient mechanical strength after assembled.
[0006] To overcome the above discussed conventional problems and accomplish the above objects,
the present invention provides an improved AC plug assembly adapted for a housing
of electric device made of insulating plastic material which is provided with two
openings. This plug assembly comprises a pin block including (a) a connecting member
and (b) a pair of plug pins integrally formed in the connecting member to permit the
plug pins to be protruded out of the housing through the openings formed in the housing.
[0007] According to the present invention, the pin block of the plug assembly is preferably
fixed to the housing by engaging between a first engaging means formed in the connecting
member in the vicinity of the base portion of the plug pin and a second engaging means
formed in the opening of the housing. The first engaging means is preferably composed
of a flange and an annular groove. The second engaging means is preferably formed
in an annular internal edge. These annular groove and annular internal edge can be
fit with each other to prevent the plug pins from falling off. Further, the connecting
member is fixed securely to the housing through another fixing means such as a screw
bolt.
[0008] Since the plug assembly according to the present invention uses a previously assembled
single member, the pin block, composed of the plug pins and the connecting member,
this plug assembly can be used as a common part to the other type housings of different
electric devices through a simple fitting manner without complicated molding steps.
In the other case, various pin blocks having different pin configurations can be easily
fabricated in accordance with desired destinations and thus fabricated pin blocks
can be fit to the same housing of electric device.
[0009] The pin block of the plug assembly according to the present invention is fixed to
the housing by engaging between the annular groove in the connecting member in the
vicinity of the base portion of the plug pin and the annular internal edge formed
in the opening surface of the housing. Since this engagement is firmly performed,
the connecting member is prevented from subjecting to the bending force owing to the
impact along the axis of the plug pin. In order to achieve this engagement, the pin
block is forcibly inserted into the two openings from the inside of the housing. This
engagement is assisted by any irreversible mechanism such as tapered edge formed in
the flange of the first engaging means.
[0010] Further, the screw member also assists the connecting member of the plug assembly
in fixing with respect to the housing. As a result, the plug assembly can be firmly
fixed to the housing by the combination of these two fixing means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other features and advantages of the invention will be apparent from the following
description taken in connection with the accompanying drawings.
Fig. 1 is a cross sectional view showing one embodiment of the plug assembly according
to the present invention.
Fig. 2 is an elevational view showing an pin block composed of a pair of plug pins
and a connecting member according to the present invention.
Fig. 3 is a plan view of the pin block shown in Fig. 2.
Fig. 4 is a partially sectional view showing a conventional plug section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] Referring to Fig. 1, there is shown one embodiment of a plug assembly according to
the present invention which is adapted for a housing 10 of electric device such as
a battery charger. The housing 10 is made of any insulating plastics, synthetic resins
or the like by molding. The housing 10 is provided with two openings 11, 11 for plug
pins 21, 21.
[0013] Fig. 2 shows a pin block 20 composed of these two plug pins 21, 21 formed in a rod
shape made of conductive metal material, and a connecting member 22 made of insulating
plastic, or synthetic resin material. These two plug pins 21, 21 are previously set
in a metal mold for molding the connecting member 22 before injecting the melted synthetic
resin into the mold.
[0014] The connecting member 22 is formed in a bridge shape whose both ends respectively
contain the plug pins 21, 21 which are arranged at a predetermined angle. In the vicinity
of each base portion of the plug pins 21, 21, the connecting member 22 further includes
a first engaging means composed of a flange 23 and an annular groove 24. The flange
23 is further provided with a tapered front edge. In this shown embodiment, the connecting
member 22 is additionally formed with a center bore for receiving a fixing means 12
such as a screw bolt.
[0015] On the other hand, each of the openings 11, 11 formed in the housing 11 is also provided
with a second engaging means whose shape corresponds to that of the first engaging
means. As shown in Fig. 1, the second engaging means is formed in an annular internal
edge 13.
[0016] In order to assemble the pin block 20 in the predetermined position of the housing
10 as shown in Fig. 1, the plug pins 21, 21 are respectively inserted into the openings
11, 11 from the inside of the housing 10 and then the flanges 23, 23 of the connecting
member 22 are pressed into the annular internal edges 13, 13. The tapered front edge
facilitates the flange 23 to be passed through the annular internal edge 13 formed
in the opening 11 and allows the annular groove 24 of the connecting member 22 and
the annular internal edge 13 to be easily engaged. Once this engagement has been performed,
the pin block 20 is kept in its predetermined position as shown in Fig. 1. Further,
the screw bolt 12 is screwed in the housing 10 so that the connecting member 22 can
be firmly fixed to the housing 10.
[0017] Obviously many modifications and variations of the present invention are possible
in the light of the above descriptions. For example, while the above described embodiment
shows two fixing means of the engagement defined between the first engaging means
23, 24 formed in the base portion of the plug pin 21 and the second engaging means
13 formed in the opening surface of the housing 10, and the fixing means 12 such as
the screw bolt, one of these fixing means may be omitted or the fixing means 12 may
be selected from more simple fixing means such as snap ring,resilient locking mechanism,
chemical bonding, thermal bonding and so on.
[0018] As given explanation above, the plug assembly according to the present invention
uses a previously assembled single member, that is the pin block, composed of the
plug pins and the connecting member, and therefore this pin block can be used as a
common part to the other type housings of different electric devices through a simple
fitting manner without complicated molding steps. In the other case, various pin blocks
having different configurations can be easily fabricated in accordance with desired
destinations and thus fabricated plug assembly can be fit to the same housing of electric
device. This assembly can realize various types of electric device having fine modified
plug shapes depending on desired plug socket shape at a low cost.
[0019] The pin block of the plug assembly according to the present invention is fixed to
the housing by engaging between the annular groove in the external surface of the
base portion of the plug pin and the annular internal edge formed in the opening surface
of the housing. Since this engagement is firmly performed, the connecting member is
prevented from subjecting to bending force owing to the external impact along the
axis of the plug pin. The pin block of this plug assembly is forcibly inserted into
the two openings from the inside of the housing to perform this engagement. Further,
this engagement can be kept by the screw bolt which assists the connecting member
of the plug assembly in fixing with respect to the housing. As a result, the pin block
of the plug assembly can be firmly fixed to the housing by the combination of these
two fixing means.
1. An improved AC plug assembly in combination with a housing (10) made of insulating
plastic material having two openings (11), comprising a pin block (20) which includes
a connecting member (22) made of insulating plastic material and a pair of plug pins
(21) made of conductive metal material, integrally formed in the connecting member
(22); and means for fixing said pin block (20) to said housing (10) so that said plug
pins (21) can be protruded out of said housing (10) through said openings (11).
2. The plug assembly as set forth in Claim 1, wherein said fixing means comprises a first
engaging means (23, 24) formed in the connecting member (22) in the vicinity of the
base portion of the plug pin (21) and a second engaging means (13) formed in the opening
(11) of the housing (10).
3. The plug assembly as set forth in Claim 2, wherein said first engaging means comprises
a flange (23) and an annular groove (24).
4. The plug assembly as set forth in Claim 2, wherein said second engaging means comprises
an annular internal edge (13) so that said annular groove (24) and annular internal
edge (13) can be fit with each other to prevent the plug pins (21) from falling off.
5. The plug assembly as set forth in Claim 1, wherein said fixing means additionally
comprises a screw bolt (12) for fixing the pin block (20) to the inside of the housing
(10).