Field of the Invention
The present invention relates to a plug-pin receiving
member gripping a plug pin, and a receptacle having the same.
Background of the Invention
As for the above receptacle, for instance, there is
known a wall-embedded receptacle attached to a mounting
frame fixed in a switch box which is installed on a back
side of a wall, and connected to an electrical wire wired
from the back side of the wall (e.g., Japanese Unexamined
Patent Application Publication No, 2006-179308).
Such a conventional receptacle includes a terminal
plate 200 including: a wire connection part 210 connected to
an electrical wire; and a plug-pin receiver 220 constituted
by a pair of gripping pieces 221 as shown in Fig. 17A. The
gripping pieces 221 are disposed forwardly of the wire
connection part 210. The gripping pieces 221 are opposed to
each other in the left-right direction Y and extend along
the up-down direction Z. As shown in Fig. 17B, the plug-pin
receivers 220 grip the plug pin 230 to hold the plug pin 230
in the terminal plate 200, So that electrical power is
supplied to the plug through the electrical wire.
By the way, in such terminal plate 200, the plug-pin
receiver 220 should be formed to have a longitudinal length
(in the up-down direction Z) larger than an outer diameter
of the plug pin 230. This makes it difficult to miniaturize
the receptacle in the up-down direction Z. On the other
hand, in case that the longitudinal length of the plug-pin
receiver 220 is shortened for the purpose of miniaturizing
the receptacle in the up-down direction 2 as shown in Fig.
17C, an electrical resistance of the plug-pin receiver 220
is increased. Accordingly, this causes the terminal plate
200 to heat up, which increases the heat generation in the
receptacle disadvantageously.
Summary of the Invention
In view of the above, an object of the present
invention is to provide a plug-pin receiving member capable
of suppressing an increase in electrical resistance as well
as an enlargement in size, and a receptacle having the same.
According to one aspect of the present invention, a
plug-pin receiving member to which a plug pin of a plug is
to be connected includes a plug-pin receiver for gripping
the plug pin that has a cylindrical part extending along an
insertion direction of the plug pin. Further, the plug-pin
receiver is provided with: a plug-pin holding part formed to
have a minimum inner diameter of the cylindrical part; and a
tip end part extended from the plug-pin holding part along
the plug-pin insertion direction, the tip end part having a
gradually increased inner diameter. Furthermore, the plug-
pin holding part makes contact with the plug pin to hold the
plug pin in the state where the plug pin is inserted into
the plug-pin receiver.
In accordance with such configuration, since the plug-
pin receiver has the cylindrical part extending along the
plug-pin insertion direction, it is possible to make the
plug-pin receiver smaller in size than a conventional plug-
pin receiver which has a terminal plate constituted by a
pair of gripping pieces as shown in Figs. 17A and 17B.
Accordingly, this promotes the miniaturization of the
receptacle. Besides, since the plug-pin receiver is formed
into a cylindrical shape, there is no need to reduce a
surface area of the plug-pin receiver even if the plug-pin
receiver is miniaturized. Consequently, the terminal plate
is avoided from increasing its electrical resistance.
Further, the tip end part is provided in the plug-pin
receiver, so that other members except for the tip end part
in the receptacle are less affected by an arc generated
between the plug-pin receiver and the plug pin as compared
with a plug-pin receiver with no tip end part.
The tip end part of the plug-pin receiver may be
configured to have a higher melting point than that of
portions other than the tip end part.
When an arc occurs, the tip end part of the plug-pin
receiver receives the arc so that temperature of the tip end
part rises up higher than that of the other portions in the
plug-pin receiver. Therefore, the tip end part is likely to
be molten by the arc as compared with the other portions.
At this point, in the present invention, the tip end part of
the plug-pin receiver is formed to have a higher melting
point than that of the other portions in the plug-pin
receiver. Accordingly, the melting of the tip end part by
the arc can be suppressed.
The plug-pin receiver may be configured to have a
plurality of gripping pieces formed by slits extending along
the plug-pin insertion direction.
According to such configuration, the slits provided in
the plug-pin receiver form the plurality of gripping pieces.
Therefore, the plug-pin receiver is easier to deform
elastically than a plug-pin receiver with no slits.
Therefore, elasticity of the plug-pin receiver is ensured.
According to another aspect of the present invention,
there is provided a receptacle including: the plug-pin
receiving member described above, a terminal plate
electrically connected to the plug-pin receiving member; and
a lock spring for pressing an electrical wire against the
terminal plate.
According to such configuration, the terminal plate
and the lock spring can fasten the electrical wire by
utilizing elasticity of the lock spring, thereby enabling to
connect the electrical wire, through which electric power is
supplied, to the terminal plate with ease.
Further, since the receptacle is provided with the
plug-pin receiving member capable of being miniaturized as
compared with the conventional plug-pin receiving member as
shown in Figs. 17A and 17B, the receptacle can be
miniaturized.
The receptacle may include: a peripheral wall
insertion groove formed into a substantially quadrangular
shape when viewed from the plug-pin insertion direction, a
peripheral wall of the plug surrounding the plug pin being
adapted to be inserted into the peripheral wall insertion
groove; and a plug receiving part surrounded by the
peripheral wall insertion groove and formed into a
substantially quadrangular shape when viewed from the plug-
pin insertion direction. The plug receiving part is
provided with a plurality of plug-pin insertion holes
disposed along a reference side that is one side of an outer
periphery of the plug receiving part, each of the plug-pin
insertion holes having a circular shape. The plug-pin
insertion holes are disposed closer to the reference side
than to an opposite side of the outer periphery of the plug
receiving part in a direction perpendicular to the reference
side.
With such configuration, an orientation of the
peripheral wall of the plug to be inserted into the
peripheral wall insertion groove is restricted compared with
a case of a peripheral wall insertion groove having an
annular shape. Accordingly, a user is easily aware of the
insertion orientation of the plug, thereby improving its
operability.
Further, since the plug-pin insertion holes are
disposed closer to the reference side than to the opposite
side of the outer periphery of the plug receiving part in
the direction perpendicular to the reference side, the plug
is prevented from being reversely inserted into the
receptacle without providing a dedicated structure for
preventing the reverse insertion to the peripheral wall
insertion groove and the peripheral wall of the plug. As a
result, an enlargement of the receptacle can be avoided as
compared with the case where the dedicated structure for
preventing the reverse insertion is provided in the
receptacle.
In accordance with of the present invention, there are
provided a plug-pin receiving member capable of suppressing
an increase in electrical resistance as well as an
enlargement in size, and a receptacle having the same.
Brief Description of the Drawings
The other objects and features of the present
invention will become apparent from the following
description of embodiments, given in conjunction with the
accompanying drawings, in which:
Fig. 1A is an exploded perspective view of a
receptacle in accordance with an embodiment of the present
invention, Fig. 1B is a plane view of the receptacle viewed
from its front side, and Fig. 1C is a plane view of the
receptacle viewed from its rear side;
Fig. 2 is an exploded perspective view of the
receptacle in accordance with the above embodiment;
Fig. 3A is an exploded perspective view showing a
terminal in accordance with the above embodiment, Fig. 3B is
a plane view of a plug-pin receiving member viewed from its
front side, and Fig. 3C is a cross-sectional view of a plug-
pin receiver of the plug-pin receiving member;
Figs. 4A to 4D are schematic perspective views showing
processes of fabricating the plug-pin receiving member in
accordance with the above embodiment;
Fig. 5 is a cross-sectional view of the receptacle in
accordance with the above embodiment;
Fig. 6A is a perspective view of a plug to be. inserted
into the receptacle in accordance with the above embodiment,
and Fig. 6B is a plane view showing a front structure of the
plug;
Fig. 7A is a perspective view of the plug and the
receptacle showing a state where the plug is inserted into
the receptacle in accordance with the above embodiment, and
Fig. 7B is a plan view of the receptacle showing a
positional relationship between plug-pin insertion holes and
plug pins when the plug is reversely inserted into the
receptacle;
Fig. 8A is a cross-sectional view of the plug-pin
receiver and the plug pin showing the state where the plug
pin is being inserted into the plug-pin receiver, Fig. 8B is
a plane view of the plug-pin receiver and the plug pin
showing the state where the plug pin is inserted into the
plug-pin receiver, and Fig. 8C is a cross-sectional view of
the plug-pin receiver and the plug pin showing the state
where the plug pin is detached from the plug-pin receiver;
Figs. 9A and 9B are plan views of the receptacle 10 in
accordance with the above embodiment showing the state where
the receptacle 10 is attached to a wall surface;
Fig. 10A is a schematic view of a receptacle with two-
piece module dimensions in accordance with a modification of
the receptacle of the above embodiment, and Fig. 10B is a
schematic view of a receptacle with three-piece module
dimensions;
Fig. 11 is an exploded perspective view of a
receptacle with a pillar terminal in accordance with another
modification of the receptacle of the above embodiment;
Fig. 12 is an exploded perspective view of a
receptacle with a screw terminal in accordance with still
another modification of the receptacle of the above
embodiment;
Fig. 13 is an exploded perspective view of a
receptacle with a solder terminal in accordance with still
another modification of the receptacle of the above
embodiment;
Fig. 14 is a perspective view of a receptacle in
accordance with still another modification of the receptacle
of the above embodiment;
Fig. 15 is a perspective view of an extension socket
to which the receptacle 10 of the above embodiment is
applied;
Figs. 16A to 16D are plan views of conventional
receptacles as comparative examples; and
Fig. 17A is a perspective view of a terminal plate of
a conventional receptacle, Fig. 17B is a plane view of a
plug-pin receiver of the conventional receptacle showing a
state where a plug pin is inserted into the terminal plate,
and Fig. 17C is a plane view of the plug-pin receiver
showing a state where the plug pin is inserted into the
terminal when the terminal plate is shortened.
Detailed Description of the Embodiments
A receptacle in accordance with an embodiment of the
present invention will be described in detail with reference
to Figs. 1A to 9B, in which the receptacle is exemplified as
a wall-embedded DC receptacle.
A configuration of the receptacle 10 will be described
with reference to Figs. 1A to 5. Hereafter, a long side
direction of the receptacle 10 is defined as "a left-right
direction Y", and a short side direction thereof is defined
as "an up-down direction Z." A direction perpendicular to
both the left-right direction Y and the up-down direction Z
is defined as "a front-rear direction X." In this
embodiment, the front-rear direction X corresponds to the
plug-pin insertion direction in which plug pins 44 (see Fig.
6) are inserted into the receptacle 10.
As shown in Fig. 1A, a body 11 and a cover 12, which
are made of a synthetic resin by injection molding, are
fixed with each other by a pair of metal assembly frames 13
to thereby form a body of the receptacle 10 with a
substantially rectangular parallelepiped shape.
The receptacle 10 is designed to have a size
conforming to Japanese Industrial Standards (see JIS C 8303).
Namely, the receptacle 10 is formed to have a size of one
module dimensions (hereinafter, referred to as "a single
module dimensions"), in which three receptacles with the
s ingle module dimens ions can be accommodated in a mounting
frame of a large rectangular string wiring accessory (see
JIS C 8375). Further, a front surface 12a of the cover 12
is formed to have a width H1 in the left-right direction Y
approximately the same as a width of the mounting frame with
a rectangular shape in the left-right direction Y.
As shown in Fig. 1B, the front surface 12a of the
cover 12 includes: a peripheral wall insertion groove 14
recessed backwardly from the front surface 12a; and a plug
receiving part 15 surrounded by the peripheral wall
insertion groove 14. The peripheral wall insertion groove
14 is formed to have a substantially quadrangular shape
whose two lower corners are cut away viewed from its front
side. A front surface 15e of the plug receiving part is
formed flush with the front surface 12a of the cover 12.
The peripheral wall insertion groove 14 includes: a
pair of first insertion grooves 14a extending along the up-
down direction Z; a pair of second insertion grooves 14b
extending along the left-right direction Y; and a pair of
inclination grooves 14c connecting the respective first
insertion grooves 14a to the lower second insertion groove
14b located. The inclination grooves 14c are provided below
the center line LI of the plug receiving part 15 in the up-
down direction Z (at the middle of the plug receiving part
15 in the up-down direction 2) . Further, at a center
portion of the lower second insertion groove 14b in the
left-right direction Y, there is provided an extension
groove 14d extending upwardly from the lower second
insertion groove 14b.
The plug receiving part 15 has first sides 15a
corresponding to the first insertion grooves 14a; second
sides 15b corresponding to the second insertion grooves 14b;
inclination sides 15c corresponding to the inclination
grooves 14c; and a recessed side 15d corresponding to the
extension groove 14d. Each of the inclination side 15c is
formed to extend in parallel to an opposite side 14e facing
to the inclination side 15c, which constitute a part of the
inclination groove 14c.
Above the center position LI of the plug receiving
part 15, a pair of plug-pin insertion holes 16 with a
circular shape viewed from its front side is provided, which
are extended through the plug receiving part in the front-
rear direction X. Namely, supposed that the upper second
side 15b is defined as a reference side KL, the plug-pin
insertion holes 16 are disposed closer to the reference side
KL than the lower second side 15b.
By the way, the peripheral wall insertion groove 14 is
formed to have different shapes depending on a type of a
power supply circuit (not shown) serving as a power supply
source. The power supply circuit is interposed between a DC
power supplying section and the receptacle 10, and, for
example, installed in a power distribution panel.
The above power supply circuit has at least two kinds
of circuits such as an ELV circuit (Extra-Low Voltage
circuit) and a SELV circuit (Safety Extra-Low Voltage
circuit) . The ELV and the SELV circuit are specified as
IEC60950-1 and IEC60335-1 by IEC standards, respectively.
Electrical appliances, such as information equipment
and lighting apparatuses, have different internal insulation
structures depending on the ELV or the SELV circuit. Namely,
an electrical appliance based on the ELV circuit requires a
strict insulation structure, that is, adopts a double
insulation structure or a reinforced insulation structure.
On the other hand, an electrical appliance based on the SELV
circuit may not adopt the double insulation structure or the
reinforced insulation structure, thereby requiring more
simplified insulation structures as compared with the
electrical appliance according to the ELV circuit.
By the way, in the case where the electrical appliance
based on the ELV circuit is connected to the receptacle 10
for the SELV circuit, there is no problem because the
electrical appliance has the strict insulation structure.
On the other hand, in the case where the electrical
appliance based on the SELV circuit is connected to the
receptacle for the ELV circuit, there is a problem such that
the electrical appliance may be destroyed when a hazardous
voltage is applied thereto because the electrical appliance
has the simplified insulation structure. Accordingly, the
receptacles 10 and the plugs 40 (see Fig. 6) , for the ELV
circuit and for the SELV circuit, need to be distinguished
from each other. Particularly, it is required to prevent
the electrical appliance based on the SELV circuit from
being connected to the receptacle for the ELV circuit by
mistake.
Accordingly, in the present embodiment, as the cover
12 for the SELV circuit, the extension groove 14d is
provided in the peripheral wall insertion groove 14. On the
other hand, as a cover for the ELV circuit, the extension
groove 14d is not provided in a peripheral wall insertion
groove. Further, a plug 40 of the electrical appliance for
the SELV circuit has a rib 45a in its peripheral wall 45.
On the other hand, a plug of the electrical appliance for
the ELV circuit has no rib 45a described above. Accordingly,
the plug for the ELV circuit can be inserted into the
peripheral wall insertion groove 14 for the SELV circuit,
whereas the plug for the SELV circuit can not be inserted
into the peripheral wall insertion groove for the ELV
circuit. Accordingly, it can be prevented that the
electrical appliance based on the SELV circuit is connected
to the receptacle for the ELV circuit by mistake.
As shown in Fig. 1C, a bottom wall 11a of the body 11
is provided with: four electrical wire insertion holes lib
into which electrical wires are to be inserted; and two
operation holes lie. Each of the electrical wire insertion
holes lib and the operation holes lie are through holes
formed through the bottom wall 11a in the front-rear
direction X.
As shown in Fig. 2, two terminals 17, four lock
springs 18, and two release buttons 19 are accommodated in
an internal space defined by the body 11 and the cover 12,
In the respective terminals 17, two lock springs 18 are
accommodated, and between the lock springs 18 in the up-down
direction, one release button 19 is disposed.
Hereinafter, connection and disconnection of the
electrical wire to and from the receptacle 10 will be
described. When the electrical wire is connected to the
receptacle 10, the electrical wire is inserted into one of
the electric wire insertion hole lib (see Fig. 1C) of the
body 11, The electrical wire comes into contact with the
lock springs 18, and then the lock spring 18 presses the
electrical wire against a portion of the terminal, which is
opposed to the lock spring 18 in the left-right direction Y.
Thus, the connection of the electrical wire to the terminal
17 is completed.
When the electrical wire is disconnected from the
receptacle 10, a tool such as a flat-blade screwdriver is
inserted into the operation hole lie {see Fig. 1C) and
pushes the release button 19 forwardly. Accordingly, the
release button 19 presses the lock spring 18 to reduce a
force of the lock spring 18 pressing the electrical wire.
in this state, when being pulled backwardly, the electrical
wire is disconnected from the receptacle 10.
A structure of the terminal 17 and a manufacturing
process of a plug-pin receiving member 30 will be described
hereinafter with reference to Figs. 3A to 4D. As shown in
Fig. 3A, the terminal 17 is formed by coupling a terminal
plate 20 to which the electrical wire is to be connected and
the plug-pin receiving member 30 for gripping the plug pin
of the plug by using the caulking rivet 25. The terminal
plate 20 and the plug-pin receiving member 30 are fabricated
by pressing a copper plate.
The terminal plate 20 includes: a pair of electrical
wire contact parts 21; a pair of lock spring terminal parts
22 spaced from the electrical wire contact parts 21 in the
left-right direction Y; and a connecting part 23 connecting
the electrical wire contact parts 21 to the lock spring
terminal parts 22 in the left-right direction Y. Between
the lock spring terminal parts 22 in the up-down directions
Z, there is provided a plug-pin receiver connecting part 24
extending backwardly from one end of the connecting part 23
in the left-right direction Y. In the plug-pin receiver
connecting part 24, there is provided an insertion hole 24a
into which the caulking rivet 25 is to be inserted, the
insertion hole 24a being a through hole formed through in
the left-right direction Y.
The plug-pin receiving member 30 is provided with: a
fixing part 31 fixed to the plug-pin receiver connecting
part 24; and a plug-pin receiver 32 with a cylindrical shape
extending forwardly from a front end of the fixing part 31.
Between the fixing part 31 and the plug-pin receiver 32, a
connecting part 36 connecting the fixing part 31 to the
plug-pin receiver 32 is provided. At a portion of the
fixing part 31 corresponding to the plug-pin receiver
connecting part 24, an insertion hole 31a is provided
likewise. In the plug-pin receiver 32, there is provided a
cylindrical body 32a with a cylindrical shape extending from
a front end of the connecting part 36 in the front-rear
direction X. The cylindrical body 32a has three slits 33
extending in the front-rear direction X, so that the
cylindrical body 32a is configured to have four gripping
pieces 34. Namely, when viewed from the front side, the
cylindrical body 32a has a substantially circular shape
formed by combining the four arch-shaped gripping pieces 34
(see Fig. 3B) .
As shown in Fig. 3C, each front portion of the
gripping pieces 34 has: a plug-pin holding part 34a adapted
to make contact with and hold the plug pin 44 (see Fig. 6);
and an arc receiving part 34b extending forwardly from the
plug-pin holding part 34a. Namely, the arc receiving part
34b is disposed closer to a tip end of the plug-pin receiver
32 than the plug-pin holding part 34a in the front-rear
direction X. The plug-pin holding part 34a has a minimum
diameter Dmin of an inner diameter D of the plug-pin
receiver 32. The arc receiving part 34b has an inclined
surface 34c with a larger inner diameter as it goes forward.
The inclined surface 34c guides the plug pin 44 into a plug-
pin holding part 34a, when the plug pin 44 is inserted
thereinto. Therefore, the plug pin 44 can be inserted into
the plug-pin receiver 32 with ease. Further, since the
inclined surfaces 34c and the plug pin 44 are in contact
with each other, the gripping pieces 34 can be easily
elastically deformed away from each other.
Herein, the arc receiving part 34b is formed to have a
higher melting point than that of the other parts of the
plug-pin receiver 32. Specifically, the arc receiving part
34b is made by nickel tungsten metal plating.
Fig. 4A shows a sheet of metal plate M. The sheet is
punched to form the fixing part 31, the connecting part 36,
and a developed plug-pin receiver 32 (see Fig. 4B). Besides,
the insertion holes 31a are provided in the fixing part 31,
and the slits 33 and the gripping pieces 34 are formed in
the plug-pin receiver 32. Then, as shown in Fig. 4C, each
of the gripping pieces 34 is bent into an arch shape by
bending work, and opposite side ends 35 of the plug-pin
receiver 32 (the cylindrical body 32a} are bent into a
circle shape around the connecting part 36 as indicated by
arrows Rl. As a result, the plug-pin receiver 32 is made
into a substantially cylindrical shape as shown in Fig. 4D.
Herein, the opposite side ends 35 of the plug-pin receiver
32 are separated from each other by a gap. Further, an
outer surface of the plug-pin receiver 32 is pressed to form
the plug-pin holding part 34a and the arc receiving part 34b
(see Fig. 3C).
The position of the terminal 17 within the receptacle
10 will be described with reference to Fig. 5. The terminal
plate 20 is accommodated in the body 11 and disposed below
the cover 12. Namely, the terminal plate 20 is located
below the peripheral wall insertion groove 14. Further, the
terminal plate 20 is positioned so as to be overlapped with
the peripheral wall insertion groove 14 in the left-right
direction Y.
The plug-pin receiving member 30 is accommodated in
the body 11 such that the plug-pin receiver 32 has a portion
extending forwardly of the body 11 and accommodated in the
cover 12. The plug-pin receiver 32 is accommodated within
an area surrounded by the peripheral plug insertion groove
14 (namely, the area corresponding to the plug receiving
part 15 in the up-down direction Z and the left-right
direction Y) . In the front-rear direction X, additionally,
the plug-pin receiver 32 is partially overlapped with the
peripheral plug insertion groove 14. In this way, only the
plug-pin receiver 32 of the terminal 17 is accommodated
within the area surrounded by peripheral wall insertion
groove 14.
Hereinafter, with reference to Figs. 6A to 7B, a
configuration of the plug 40 will be described, and
connection and disconnection structures of the plug 40 to
and from the receptacle 10 will be described with reference
to Figs. 8A to 8C.
As shown in Fig. 6A, the plug 40 includes: a cable
part 42; and a plug main body 41 connected to the cable part
42. The plug main body 41 include a surface 43 adapted to
be opposite to the plug receiving part 15 (see Figs. 7A and
7B) in the front-rear direction X; two round plug pins 44
extending backwardly from the surface 43; and a peripheral
wall 45 surrounding the plug pins 44 from the outside. The
peripheral wall 45 has the same shape as the peripheral wall
insertion groove 14 (see Figs. 7A and 7B) . Further, rear
ends of the plug pins 44 are located slightly forward of a
rear end surface of the peripheral wall 45.
As shown in Fig. 6B, the plug pins 44 are disposed
above the center line L2 of the peripheral wall 45 in the
up-down direction Z. Further, the plug pins 44 are arranged
along the left-right direction Y. The plug pins 44 include
a positive plug pin (e.g., left-hand side in Fig. 6B) , and a
negative plug pin (e.g., right-hand side in Fig. 6B).
As shown in Fig. 7A, at the time when the plug 40 is
inserted into the receptacle 10, the peripheral wall 45 is
inserted into the peripheral wall insertion groove 14. Then,
the plug pins 44 are inserted into the plug-pin insertion
holes 16. Herein, the plug-pin insertion holes 16 include a
positive plug pin insertion hole for inserting the positive
plug pin and a negative plug pin insertion hole for
inserting the negative plug pin.
As shown in Fig. 7B, when the plug 40 ^ould be
reversely inserted into the receptacle 10, the plug pins 44
are positioned below the center line LI of the plug
receiving part 15. Consequently, since the plug pins 44
come into contact with the front surface 15e of the plug
receiving part 15, it becomes difficult to insert the plug
4 0 into the receptacle 10.
Note that *the reverse insertion" means that the positive plug pin of the plug is inserted in the negative
plug pin insertion hole and the negative plug pin of the
plug is inserted in the positive plug pin insertion hole.
If the reverse insertion is carried out, the electrical
appliance connected to the plug pins 44 may be damaged
because an inappropriate voltage is applied to the plug pins
44.
Even if the reverse insertion of the plug pins 44 into
the plug-pin insertion holes 16 is attempted, the reverse
insertion can be reliably prevented because the plug pins 44
and the plug-pin insertion holes 16 are separated from each
other in the up-down direction Z.
As shown in Fig. 8A, when the plug pin 44 is inserted
into the plug-pin receiver 32, the plug-pin receiver 32 is
elastically deformed away from each other as shown by arrows
Yl as a tip end part 44a of the plug pin 44 is moved from
the arc receiving part 34b to the plug-pin holding part 34a.
Specifically, the gripping pieces 34, which are opposed to
each other through the plug pin 44 in a diametric direction,
are elastically deformed away from each other as shown in
Fig. 8B. Then, the plug pins 44 are held by a . recovery
force of the plug-pin receiver 32 (the recovery force of
each gripping piece 34) . Further, the plug pins 44 are held
by being in line contact with the four gripping pieces along
the circumferential direction thereof.
On the other hand, when the plug pins 44 are
disconnected from the receptacle 10, the gripping pieces 34
of the plug-pin receiver 32 are deformed to come closer to
each other by their own recovery forces as shown by arrows
Y2 as the tip end part 44a of the plug pin 44 moves from the
plug-pin holding part 34a to the arc receiving part 34b.
Further, when the plug pin 44 is pulled out from the plug-
pin receiver 32, the plug-pin receiver 32 is returned to its
initial state before the insertion of the plug pin 44.
Further, when the plug pin 44 moves from the plug-pin
holding part 34a to the arc receiving part 34b, an arc may
occur between the plug pins 44 and the plug-pin receiver 32.
The arc, however, is received by the arc receiving part 34b.
Now, various arrangements of the receptacle 10 will be
described with reference to Figs. 9A and 9B. As shown in
Fig. 9A, in the state where one receptacle 10 is attached to
a mounting frame, a decorative plate 50 is attached to the
mounting frame from its front side. The decorative plate 50
has an opening hole 51 with the single module dimensions
formed to expose the front surface 12a of the cover 12.
As shown in Fig. 9B, since the receptacle 10 is
designed to have the single module dimensions, another
receptacle 10 or other wiring accessories, which have the
single module dimensions or double module dimensions
standardized by Japanese Industrial Standards (e.g., an
outlet 53 for coaxial cables and a modular jack 54 for
telephone lines), can be attached to the mounting frame.
Namely, the receptacle 10 and the above wiring accessories
can be attached to the common mounting frame. Note that the
decorative plate 50 is provided with the opening hole 52
having three-piece module dimensions. Besides, note that
the above wiring accessories are not limited to the outlet
53 and the modular jack 54, other wiring accessories such as
an AC receptacle and a modular jack for LAN cables may be
employed.
According to the plug-pin receiving member 30 of the
present embodiment and the receptacle 10 having the same,
the following effects will be expected.
(1) According to the present embodiment, the plug-pin
receiver 32 is configured to have the cylindrical body 32a
with a cylindrical shape. Therefore, the plug-pin receiver
32 can be miniaturized in the up-down direction Z as
compared with the conventional plug-pin receiver 220 shown
in Figs. 17A and 17B. As a result, the miniaturization of
the receptacle 10 in the up-down direction Z can be realized.
Further, it is possible to enlarge a surface area of the
plug-pin receiver 32 as compared with the conventional plug-
pin receiver 220 miniaturized in the up-down direction Z
shown in Fig. 17C. Consequently, this embodiment can
suppress an increase in the electric resistance of the plug-
pin receiver 32 as compared with the conventional plug-pin
receiver 220 shown in the above Fig. 17C.
Further, since such conventional plug-pin receiver 220
is configured to be in two-point contact with the plug pin
230, the plug pin 230 is held unstably. On the contrary,
the plug-pin receiving member 30 of the present embodiment
is formed to have the cylindrical plug-pin receiver 32.
Therefore, the plug pin 44 can be in contact with the plug-
pin receiver 3 2 over its circumference, thereby enabling the
plug-pin receiver 32 to hold the plug pin 44 stably.
(2) According to the present embodiment, the
receptacle 10 is configured to have the single module
dimensions and the peripheral wall insertion groove 14 is
formed in the cover 12. Therefore, a pair of plug-pin
receivers 32 needs to be accommodated within an area
surrounded by the peripheral wall insertion groove 14. In
such configuration, since the conventional plug-pin receiver
220 is formed to have a larger volume in the up-down
direction Z, it is difficult to accommodate the plug-pin
receiver 220 within the area surrounded by the peripheral
wall insertion groove 14. On the contrary, the receptacle
10 of the present embodiment is miniaturized in the up-down
direction Z because the plug-pin receiver 32 has a
cylindrical shape. Therefore, the plug-pin receiver 32 can
be accommodated within the area surrounded by the peripheral
wall insertion groove 14. Further, the terminal plate 20 is
disposed below the peripheral wall insertion groove 14.
Hence, even if the terminal plate 20 is disposed outside the
area surrounded by the peripheral wall insertion groove 14,
the enlargement of the receptacle 10 can be suppressed.
Furthermore, the plug-pin insertion holes 16 are
provided above the center line LI of the plug receiving part
15. Therefore, in the case where such configuration is
employed in the conventional plug-pin receiver 220 shown in
Fig. 17A, only an upper end portion of the plug-pin receiver
220 can be overlapped with the plug-pin insertion hole 16
because the plug-pin receiver 220 is needed to be
accommodated within the area surrounded by the peripheral
wall insertion groove 14. Accordingly, the plug pin 230
will be held by only the upper end portion of the plug-pin
receiver 220. Consequently, the conventional plug-pin
receiver 220 is unable to hold the plug pin 230 stably. On
the contrary, the receptacle 10 of the present embodiment is
formed to have the plug-pin receiver 32 with a cylindrical
shape extending in the front-rear direction X at the
corresponding position of the plug-pin insertion hole 16.
Accordingly, the plug-pin receiver 32 is able to hold the
plug pins 44 stably.
(3) According to the present embodiment, the plug-pin
receiver 32 is formed by bending. Accordingly, the
elasticity of the plug-pin receiver 32 is ensured as
compared with a plug-pin receiver fabricated by cutting.
Further, the plug-pin receiver 32 can be manufactured easily
as compared with a plug-pin receiver fabricated by drawing.
(4) According to the present embodiment, the plug-pin
receiver 32 is provided with the slits 33. This gives a
higher elasticity to the plug-pin receiver 32 as' compared
with a plug-pin receiver with no slits 33. As a result, the
plug-pin receiver 32 can hold the plug pin 44 stably.
Further, the plug-pin receiver 32 comes into contact with
the plug pin 44 at more points as compared with the
conventional plug-pin receiver 220 shown in Fig. 17B.
Accordingly, an electric contact between the plug-pin
receiver 32 and the plug pin 44 is secured.
(5} According to the present embodiment, the arc
receiving part 34b is provided in the plug-pin receiver 32.
Accordingly, other members of the receptacle 10, such as the
cover 12, are less affected by the arc as compared with a
plug-pin receiver with no arc receiving part 34b.
Consequently, the influence to the other members of the
receptacle 10, such as the cover 12, can be suppressed as
compared with the plug-pin receiver with no arc receiving
part 34b because the arc receiving part 34b receives the arc.
In this embodiment, especially, since a DC receptacle
is used as the receptacle 10, the arc is sustained for a
longer time compared with an AC receptacle. Therefore, the
members such as the plug-pin receiver 32 and the cover 12
are likely to be affected by the arc. Since the arc
receiving part 34b receives the arc, however, the influence
to the other members can be reduced. Consequently, the
present embodiment is suitable for a DC receptacle.
(6) According to the present embodiment, the arc
receiving part 34b is formed to have a higher melting point
than that of the other parts of the plug-pin receiver 32.
Accordingly, the arc receiving part 34b is prevented from
melting due to the arc.
(7) According to the present embodiment, the
peripheral wall insertion groove 14 is configured to have a
substantially quadrangular shape whose two lower corners are
cut away. Therefore, this restricts an orientation of
inserting the peripheral wall 45 of the plug 40 as compared
with the receptacle 100 whose peripheral wall insertion
groove ill is annular as shown in Figs. 16A and 16B, based
on IEC standards. Accordingly, since a user is easily aware
of the insertion orientation of the plug 40 into the
receptacle 10, its operability is improved. Consequently,
the user can eas ily insert the plug 4 0 into the receptacle
10 while suppressing the reverse insertion.
Further, the plug-pin insertion hole 16 is disposed
above the center line LI of an outer periphery of the plug
receiving part 15. Accordingly, the reverse insertion of
the plug 4 0 into the receptacle 10 can be suppressed without
providing a dedicated structure for preventing the reverse
insertion in the peripheral wall insertion groove 14 and the
peripheral wall 45. As a result, the enlargement of the
receptacle 10 can be suppressed as compared with a
receptacle having the dedicated structure for preventing the
reverse insertion.
By the way, if the peripheral wall insertion groove
111 has an annular shape as shown in Fig. 16B, the following
problem will be caused. That is, when the plug-pin
insertion holes 112 are disposed on the upper half side in
the circle, the distance between the plug-pin insertion
holes 112 is reduced to decrease their dielectric strength.
Further, it is supposed that the peripheral wall insertion
groove 111 has a quadrangular shape and the plug-pin
insertion hole has a rectangular shape whose longer side
extends in the up-down direction Z as shown in Fig. 16C.
When the plug-pin insertion holes 112 are disposed on the
upper half side in the quadrangle as shown in Fig. 16D, it
is required to enlarge an outer shape of the receptacle 100.
On the contrary, in the present embodiment, the plug-
pin insertion hole 16 is formed to have a circular shape
while the peripheral wall insertion groove 14 is formed to
have a quadrangular shape. Therefore, even if the plug-pin
insertion holes 16 are disposed above the center line LI, it
is prevented that the distance between the plug-pin
insertion holes 16 is reduced. Consequently, this improves
their dielectric strength as compared with the receptacle
100 shown in Fig. 16D. Further, unlike the receptacle 100
in Fig. 16D, there is no need to enlarge its outer shape,
and the receptacle 10 can have the single module dimensions.
(8) According to the present embodiment, the
receptacle 10 is formed to have a size of the single module
dimensions based on Japanese Industrial Standards, in which
three receptacles with the single module dimensions can be
accommodated in a mounting frame of a large rectangular
string wiring accessory. Therefore, the receptacle 10 can
be attached to a mounting frame of the other wiring
accessories standardized by the same standards. Accordingly,
there is no necessary to manufacture a dedicated mounting
frame for the receptacle 10 independently, and the mounting
frame can be used commonly. Consequently, the receptacle 10
can be attached to the mounting frame together with the
other wiring accessories having the single module dimensions
or the two-piece module dimensions, thereby improving its
operability.
(9) According to the present embodiment, the front
surface 15e of the plug receiving part 15 and the front
surface 12a of the cover 12 are formed flush with each other
in the front-rear direction X. Further, the plug pins 44
are configured to be located slightly forward of the rear
end portion of the peripheral wall 45. According to such
configurations, when the plug 40 is reversely inserted into
the receptacle 10, the plug pins 44 come into contact with
the plug receiving part 15 before the peripheral wall 45 is
excessively inserted into the peripheral wall insertion
groove 14, Accordingly, a user is aware of the reverse
insertion more clearly, and additionally, the plug 40 is
avoided from remaining in the receptacle 10 when being
inserted reversely. Accordingly, the state of the reverse
insertion is prevented from being maintained.
(10) According to the present embodiment, the ends 3 5
of the cylindrical body 32a are configured to be separated
from each other. Therefore, the elasticity of the two
gripping pieces 34 which have the ends 35 can be increased
as compared with that of a cylindrical body of which the
ends 3 5 are connected to each other. As a result, the
elasticity of the plug-pin receiver 32 can be ensured.
(Other embodiments)
The receptacle 10 of the present invention may be, not
limited to the above embodiment, modified as follows.
Further, the following modifications may be each applied to
the above embodiment and the combination of the different
modifications may also be possible.
In the above embodiment, the receptacle 10 is applied
to a DC receptacle. The receptacle 10, however, may be
applied to an AC receptacle, which supplies AC power.
In the above embodiment, the plug-pin insertion holes
16 are disposed above the center line LI. The plug-pin
insertion holes 16, however, may be disposed at or below the
center line LI.
In the above embodiment, the receptacle 10 is formed
to have the single module dimensions. The receptacle 10,
however, may be formed to have the two-piece module
dimensions shown in Fig. 10A, or the three-piece module
dimensions shown in Fig. 10B.
In the above embodiment, the connection structure of
the terminal 17 and an electrical wire is a so called quick
connection terminal structure which uses the lock spring 18
and the release button 19. The connection structure of the
terminal 17 and the electrical wire, however, is not limited
to the quick connection terminal structure. For instance,
as shown in Fig. 11, a pillar terminal 60 may be used
instead of the terminal 17. The pillar terminal 60
includes: a wire holding part 61 with a frame shape whose
lower end is opened; a plug-pin receiver 62 extending
forwardly and connected to the wire holding part 61; and a
screw 63 to be screwed to the wire holding part 61. The
plug-pin receiver 62 is identical to the plug-pin receiver
32. Herein, the electric wire is inserted into the wire
holding part 61, and then is fastened between the end of the
shaft body of the screws 63 and the wire holding part 61.
In this way, the pillar terminal 60 holds the electric wire.
Further, as shown in Fig. 12, a screw terminal 70 may
be used instead of the terminal 17. The screw terminal 70
is configured such that a terminal plate 71 and a plug-pin
receiving member 72 are coupled together by a caulking rivet
73, and a screw 79 is screwed to the terminal plate 71. The
terminal plate 71 includes; a screw fixing part 74; a plug-
pin receiver fixing part 75 to which the plug-pin receiving
member 72 is fixed, the plug-pin receiver fixing part 75
being spaced from and opposed to the screw fixing part 74
through a gap in the left-right direction Y; and a
connecting part 76 connecting the screw fixing part 74 and
the plug-pin receiver fixing part 75. The plug-pin
receiving member 72 includes: a fixed part 77 fixed to the
plug-pin receiver fixing part 75; and a plug-pin receiver 78
extending forwardly from the fixed part 77. The plug-pin
receiver 78 is identical to the plug-pin receiver 32.
Further, the screw 79 is screwed in the screw fixing part 74.
Herein, the electric wire is inserted into between the screw
fixing part 74 and a screw head 79a of the screw 79 in the
left-right direction Y, and then is fastened between the
screw fixing part 74 and the screw head 79a by screwing the
screw 79. In this way, the screw terminal 70 holds the
electric wire.
Further, as shown in Fig, 13, a solder terminal 80 may
be used instead of the terminal 17. The solder terminal 80
includes: a wire connection part 81 to which an electrical
wire is to be connected; and a plug-pin receiver 82
extending forwardly from the wire connection part 81. The
plug-pin receiver 82 is identical to the plug-pin receiver
32. The wire connection part 81 is accommodated in a
terminal accommodation part lid formed in the body 11 so as
to protrude rearwardly of a bottom wall of the body 11.
Then, in this state, an electrical wire is soldered to the
wire connection part 81.
In the above embodiment, the peripheral wall insertion
groove 14 is provided with two inclination grooves 14c and
one extension groove 14d. The shape of the peripheral wall
insertion groove 14 is, however, not limited thereto. For
instance, in the peripheral wall insertion groove 14, the
inclined grooves 14c and extension groove 14d may be omitted
as shown in Fig. 14. In other words, the peripheral wall
insertion groove 14 may have a substantially quadrangular
shape viewed from its front side. In this case, the plug-
pin receiver 15 is also formed to have a substantially
quadrangular shape viewed from its front side. With such
configuration, an effect similar to the effect (7) of the
above embodiment can be expected.
Further, depending on the shape of the peripheral wall
insertion groove 14, a type of supply voltage suitable for
the receptacle 10 can be changed. Specifically, the shape
of the peripheral wall insertion groove 14 shown in Fig. 14
may be suitable for the receptacle 10 of a supply voltage
24V, whereas the shape of the peripheral wall insertion
groove 14 with a quadrangular shape whose both lower corners
are cut away to provide the inclined grooves 14c may be
suitable for the receptacle 10 of a supply voltage 48V.
Further, the peripheral wall insertion groove 14 may have a
quadrangular shape whose one lower corner is cut away to
provide the inclined grooves 14c. This may be suitable for
a receptacle of a supply voltage 12V or 6V, for example.
In the above embodiment, only the power pin insertion
holes 16 are provided in the plug receiving part 15.
However, as shown in Fig. 14, a ground pin insertion hole
16a may be provided in addition to the power pin insertion
holes 16. In this case, the ground pin insertion hole 16a
is disposed below the center line LI and at a center of the
plug receiving part 15 in the left-right direction Y. With
such configuration, the terminal 17 is constituted by two
terminals corresponding to the power pin insertion holes 16
and one terminal corresponding to the ground pin insertion
hole 16a.
In the above embodiment, the receptacle 10 is used for
a wall-embedded receptacle. The receptacle 10, however, is
not limited thereto. For instance, the receptacle 10 is
also applicable to an extension socket 90 as shown in Fig.
15.
In the above embodiment, the arc receiving part 34b is
formed to have a higher melting point than that of the other
parts of the plug-pin receiver 32 by performing a nickel-
tungsten plating thereon. However, a method for providing
the arc receiving part 34b with a higher melting point is
not limited to the above. For instance, by using a clad
material which is a metal plate of composite material, the
arc receiving part 30 may be formed of a material having a
higher melting point (e.g., tungsten) than that of the other
parts.
In the above embodiment, the peripheral wall insertion
groove 14 is formed to have the substantially rectangular
shape of which the long s ide extends in the left- right
direction Y and the short side extends in the up-down
direction Z. The shape of the peripheral wall insertion
groove 14, however, is not limited to the above. The
peripheral wall insertion groove 14 may be formed to have a
square shape in which both lengths of the left-right
direction Y and the up-down direction Z are the same.
In the above embodiment, the peripheral wall insertion
groove 14 and the plug receiving part 15 are formed into
substantially quadrangular shapes of which two lower corners
are cut away respectively. However, the shapes of the
peripheral wall insertion groove 14 and the surface part 15
are not 1 imited to the above. For instance, the peripheral
wall insertion groove 14 and the plug receiving part 15 may
be formed to have a substantially quadrangular shape, in
which the inclined grooves 14c and the inclined sides 15c
are omitted as shown in Fig. 14. Further, the shapes of the
peripheral wall insertion groove 14 and the plug receiving
part 15 are not limited to the substantially quadrangular
shape. The peripheral wall insertion groove 14 may have an
annular shape, and the plug receiving part 15 may have a
circular shape. Even in such configuration, an effect
similar to the effect (1) of the above embodiment can be
expected.
In the above embodiment, although the plug-pin
insertion hole 16 is formed to have the round shape, the
shape of the plug-pin insertion hole 16 is not limited
thereto. For instance, the plug-pin insertion hole 16 may
be formed to have a rectangular shape of which a long side
extends in the up-down direction Z and a short side extends
in the left-right direction Y. Even in such configuration,
an effect similar to the effect (1) of the above embodiment
can be expected.
In the above embodiment, the peripheral wall insertion
groove 14 is formed in the cover 12. The peripheral wall
insertion groove 14, however, may be omitted, and the
peripheral wall 45 of the plug 40 may also be omitted
accordingly.
In the above embodiment, the terminal plate 20 and the
plug-pin receiving member 30 are coupled together with the
caulking rivet 25. However, a method for coupling the
terminal plate 20 and the plug-pin receiving member 30
together is not limited to the above. For instance, the
plug-pin receiving member 30 may be fixed to the terminal
plate 20 by welding.
Further, although the plug-pin receiving member 30 and
the terminal plate 20 are formed as separate members, the
plug-pin receiving member 30 and the terminal plate 20 may
also be formed as a single member. This can reduce the
number of components of the terminal 17.
In the above embodiment, the cylindrical body 32a is
formed as the cylindrical part of the plug-pin receiver 32.
However, the cylindrical body may have other shape than a
cylindrical shape as long as it has a tubular shape. For
instance, the body may be a tube with a substantially
quadrangular shape when viewed from the front.
While the invention has been shown and described with
respect to the embodiments, it will be understood by those
skilled in the art that various changes and modification may
be made without departing from the scope of the invention as
defined in the following claims.
We Claim:
1. A plug-pin receiving member to which a plug pin of a
plug is to be connected, comprising:
a plug-pin receiver for gripping the plug pin, the
plug-pin receiver having a cylindrical part extending along
an insertion direction of the plug pin,
wherein the plug-pin receiver comprises:
a plug-pin holding part that is formed to have a
minimum inner diameter of the cylindrical part; and
a tip end part extended from the plug-pin holding part
along the plug-pin insertion direction, the tip end part
having a gradually increased inner diameter; and
wherein the plug-pin holding part makes contact with
the plug pin to hold the plug pin in a state where the plug
pin is inserted into the plug-pin receiver.
2. The plug-pin receiving member as set forth in Claim 1,
wherein the tip end part of the plug-pin receiver has a
higher melting point than that of portions other than the
tip end part.
3. The plug-pin receiving member as set forth in Claim 1
or 2, wherein the plug-pin receiver is provided with a
plurality of gripping pieces formed by slits extending along
the plug-pin insertion direction.
4. A receptacle comprising:
the plug-pin receiving member described in any one of
Claims 1 to 3;
a terminal plate electrically connected to the plug-
pin receiving member; and
a lock spring for pressing an electric wire against
the terminal plate.
5. The receptacle as set forth in Claim 4, wherein the
receptacle comprises:
a peripheral wall insertion groove formed into a
substantially quadrangular shape when viewed from the plug-
pin insertion direction, a peripheral wall of the plug
surrounding the plug pin being adapted to be inserted into
the peripheral wall insertion groove; and
a plug receiving part surrounded by the peripheral
wall insertion groove and formed into a substantially
quadrangular shape when viewed from the plug-pin insertion
direction,
wherein the plug receiving part is provided with a
plurality of plug-pin insertion holes disposed along a
reference side that is one side of an outer periphery of the
plug receiving part, each of the plug-pin insertion holes
having a circular shape, and
wherein the plug-pin insertion holes are disposed
closer to the reference side than to an opposite side of the
outer periphery of the plug receiving part in a direction
perpendicular to the reference side.

ABSTRACT

A plug-pin receiving member,
to which a plug pin of a plug is to be connected, includes a plug-pin receiver for gripping
the plug pin. The plug-pin receiver has a cylindrical
part extending along an insertion direction
of the plug pin. The plug-pin receiver includes
a plug-pin holding part that is formed to
have a minimum inner diameter of the cylindrical
part, and a tip end part extended from the
plug-pin holding part along the plug-pin insertion direction, the tip end part having a gradually
increased inner diameter. The plug-pin
holding part makes contact with the plug pin to
hold the plug pin in a state where the plug pin
is inserted into the plug-pin receiver.