TECHNICAL FIELD The present invention relates to a power plug adapter, and more particularly, to a power plug adapter capable of turning on/off power transferred to a load device and compatibly using power plugs having different connection terminals according to a supply voltage.

BACKGROUND ART Generally, a power plug is connected to a load device by a power supply line and fitted into a receptacle for connecting a power source. The power plug is composed of a terminal bar connected to a power supply line and fitted into a receptacle, and a case for supporting the terminal bar.

According to the conventional power plug, the terminal bar is fixed by the case and thereby a direction that the plug is fitted is fixed as one direction when the terminal bar is fitted into the receptacle. Therefore, when a plurality of plugs are to be coupled to one another, adjacent plugs and power supply lines cause interference thus to have a difficulty in coupling and separating the power plugs. Also, the power supply lines are arranged with a twisted state according to positions of the load device and the receptacle.

Also, in case of shielding a power source transferred to the load device, the terminal bar of the plug has to be plugged off the receptacle thereby to have a difficulty in using.

Especially, if only the power of the load device is turned off under a state that the power plug is fitted into the receptacle since the separation and connection of the power plug and the receptacle are difficult, a power consumption is increased, a life span of the load device is reduced, and fire due to an overload can be generated.

In order to solve said problem of the power plug, in a rotary power plug of Korean publication utility model 8705892, a middle rotary disc to which a power supply line is connected is rotatably connected to a plug body having a plug terminal, power sources of the middle rotary disc and the plug body are connected by a conducting plate, and a plate spring is disposed between the middle rotary disc and an upper rotary disc disposed at the upper side of the middle rotary disc so that the conducting plate can be connected to the plug body.

In the rotary power plug, the plug body having the plug terminal and the middle rotary disc to which the power supply line is connected are relatively rotated each other.

In the rotary power plug, the middle rotary disc is rotatably coupled to the plug body thereby to be able to change the position of the power supply line. However, the conducting plate is in a state of being always connected to the plug body thereby not to be able to turn on/off power transferred to the load device. Therefore, in case of turning off power, the power plug has to be plugged off the receptacle thus to have a difficulty in using.

Also, a plug according to Korean publication utility model 93-22426

comprises: a fixed member that upper and contact terminals are fixed; and a rotary member rotatably and elastically connected to one side surface of the fixed member and to which a power supply line is fixed downwardly, wherein a power source transferred to the upper and contact terminals continually flows through the power supply line even if the power supply line is moved with several angles at the time when the rotary member is rotated.

In said plug, the rotary member to which the power supply line is fixed is relatively rotated with the fixed member to which the upper and lower terminals are fixed thereby to be able to change the position of the power supply line. However, due to no function to shield power transferred to the load device, the plug has to be plugged off the receptacle at the time of shielding the power source thereby to have a difficulty in using.

In order to solve said problem of the plug, a power plug according to Korean publication utility model 99-34732 discloses a function to turn on/off power transferred to the load device in the plug itself.

That is, the power plug comprises: an external power input unit inserted into a receptacle for receiving an external power; a power control unit having a conductive power supply/shield unit for supplying and shielding an external power inputted into the external power input unit to an electronic product; and a power display unit for informing that an external power is being supplied to a load device or is being shielded.

In said plug, power supplied to the load device can be turned on/off by rotating the power control unit in a state that the plug has been inserted

into the receptacle. However, since the power control unit is easily rotated by an external force, a controlled position thereof by a rotation can not be stably maintained.

When the power control unit is rotated by the external force, power can not maintain an'on'state of an'off'state and thereby power transferred to the load. device is suddenly shielded or connected thus to cause a damage to the load device.

There are also provided a plug according to Japanese publication utility model 1994-58585 and a plug according to Korean publication utility model 99-17451, in which the plugs are rotatable thus to change the position of a power supply line. However, said plugs have the aforementioned problems, either.

Also, there is provided a power plug according to Korean publication utility model 2000-0031973 capable of connecting and separating a main terminal and a connection terminal by rotating an adjust unit, which comprises a connection portion having a main terminal fitted into a receptacle connection portion of interior wiring, and an adjust unit rotatably disposed at an upper portion of the connection portion and having a connection terminal.

Said power plug is constructed as follows. A supporting body having the main terminal and a guide block are fixed by a screw, thereby fitting one end of the main terminal into one side surface of a terminal hole of the guide block. Herein, a guide pin which receives an elasticity force by a spring is fitted into the terminal hole of the guide block so that the end of

the guide pin can be fixed to a coupling hole of an adjust block, and the connection terminal connected with a cable is arranged at an inner surface of the adjust block. Also, a part of the connection terminal is fitted into another side surface of the terminal hole of the guide block thus to come in contact with the main terminal. An inserting groove is formed in a right angle direction of the terminal hole so that the connection terminal of the adjust block can be fitted into the inserting groove when the adjust block is rotated in a right angle direction of the guide block.

However, said power plug has problems. That is, the terminal hole is formed at the guide block, the mounting groove is formed towards the right angle direction of the terminal hole, and the spring for pressurizing the adjust block downwardly is coupled to the lower side portion of the guide pin coupled to the guide block and the adjust block. According to this, at the time of adjusting the position of the adjust block, the adjust block is rotated by 90° for the guide block so that the connection terminal of the adjust block can be fitted into the terminal hole or the mounting groove.

Herein, the adjust block can be rotated only by 90°, and in order to adjust the position of the adjust block, the adjust block has to pulled towards outside of a central axis and then be rotated by 90°. Also, the connection terminal of the adjust block has to be fitted into the terminal hole or the mounting groove individually so that contact points therebetween can be in contact with or separated from each other, thereby having a problem that the handling is complicated and difficult.

Also, there is provided a one-touch power plug according to

Korean publication utility model 2000-007391, in which a coil spring is inserted into a terminal body, a middle plate, and a push plate.

In said one-touch power plug, a semi-circular shape terminal sheet is fixed to the center of the terminal body thus to be connected to the terminal bar, and saw teeth are formed at an outer surface of the terminal body and a side surface of the middle plate. Also, a cylinder where a rail groove is formed at both sides thereof is protruded from the middle plate. A spring is installed at one side of the middle plate, and a guide path where a protrusion sheet is protrudingly-formed and a rail protrusion are formed at the center of the push plate. When the protrusion sheet is inserted into the cylinder of the middle plate, the rail protrusion is inserted into the rail groove of the inner surface of the cylinder and the spring is inserted into the guide path.

However, in said one-touch power plug, saw teeth are formed at the main walls of the terminal body and the middle plate, the cylinder of the middle plate is rotatably inserted into the guide path of the terminal body, and the coil spring is inserted between the terminal body and the middle plate. Therefore, as the middle plate and the push plate are rotated, the rotation position can be controlled as various angles. However, by the rotation of the middle plate and the push plate, a function for naturally controlling the height between the terminal body and the middle plate can not be anticipated and a function for contacting or separating the contact points by the height control function can not be anticipated, either.

Moreover, even if the rotation positions of the push plate and the

middle plate can be controlled, the push plate and the middle plate can not be stably adhered to the terminal body at a rotated position. Also, it is impossible to control a rotation position of the upper body by a simple operation for rotating the upper body like the adapter according to the present invention, and contact points can not be naturally in contact with or separated from each other.

The present applicant disclosed a rotation switch plug by considering the above problems and registered as Korean utility model No.

263859. In the rotation switch plug, convex-concave portions of a triangle shape are formed at upper and lower bodies. The convex-concave portion of the upper body is composed of a plurality of convex portions and concave portions constantly. Also, the convex-concave portion of the lower body is composed of a first concave portion formed to correspond to the convex-concave portion of the upper body, and a second concave portion formed between each convex portion with a depth shallower than the first concave portion. A spring for downwardly pressing the upper body is coupled to an upper portion of an axial bar coupled to the upper and lower bodies. According to this, the rotation position can be variously controlled by a simple operation for rotating the upper body. Thus, as the convex portion of the convex-concave portion of the upper body comes in contact with the first concave portion or the second concave portion of the convex- concave portion of the lower body, a height of the upper body can be naturally controlled.

Accordingly as the height of the upper body is controlled, a pair of

input terminals fixed to a lower surface of the upper body naturally come in contact with or separate from a pair of connection terminals fixed to an upper surface of the lower body, thereby connecting or shielding a power.

In the rotation switch plug, the rotation position of the upper body is controlled by a simple operation for rotating the upper body, contact points naturally come in contact with or separate from each other, and a controlled position can be stable maintained.

However, said power plug and the plug adapter are constructed to use only one between a low voltage plug having a plate-type terminal and a high voltage plug having a bar-type terminal, so that a different power plug with respect to a usage area and a usage nation can not be used.

TECHNICAL GIST OF THE PRESENT INVENTION Therefore, an object of the present invention is to provide a power plug adapter capable of turning on/off a power transferred to a load device by being connected between a power plug connected to a load device and a power input side receptacle and capable of compatibly using two kinds of power plugs by a voltage difference.

DETAILED DESCRIPTION OF THE INVENTION In order to achieve the above objects, there is provided a power plug adapter including : an upper body; a connection terminal mounted at the upper body for selectively inserting either a bar-type terminal or a plate- type terminal of a power plug ; an input terminal attached to a lower surface

of the upper body and connected to the connection terminal ; a lower body rotatably supported at the lower surface of the upper body; a terminal bar mounted at the lower body and inserted into a receptacle ; a contact terminal connected to the terminal bar and attached to an upper surface of the lower body thus to be in contact with the input terminal ; and a power ON/OFF unit for contacting or separating the input terminal and the contact terminal by a relative rotation of the upper body and the lower body.

The connection terminal is integrally composed of a first connection portion for inserting the bar-type terminal of the power plug, and a second connection portion for inserting the plate-type terminal of the power plug The first connection portion is formed as a cylindrical shape of which one side is opened, and the second connection portion is integrally extended from the first connection portion and is formed as a rectangular plate shape of which one side is opened.

A hinge shaft is fixed to the lower body, and the hinge shaft is inserted into a hinge hole formed at the upper body thus to rotatably support the upper body. Also, a spring is coupled to the hinge shaft thus to provide a certain elastic force in a direction that the upper body comes in contact with the lower body.

The power ON/OFF unit includes: first grooves formed at an upper surface circumference of the lower body with certain interval and depth; second grooves respectively formed between the first grooves and protruding more upwardly than the first grooves with a certain height; and protrusions formed at a lower surface circumference of the upper body with

a certain interval thus to be selectively inserted either into the first grooves or into the second grooves.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view showing a power plug adapter according to the present invention; Figure 2 is a disassembled perspective view of the power plug adapter according to the present invention; Figure 3 is a disassembled perspective view of upper and lower adapters of the power plug adapter according to the present invention; Figure 4 is an engagement section view of the power plug adapter according to the present invention; Figure 5 is a bottom view of the upper adapter of the power plug adapter according to the present invention; and Figure 6 is an upper surface view of the lower adapter of the power plug adapter according to the present invention.

MODE FOR CARRYING OUT THE PREFERRED EMBODIMENTS The present invention will now be described with reference to accompanying drawings.

Even if a plurality of embodiments for a power plug adapter according to the present invention can exist, the most preferred embodiment will be explained hereinafter.

Figure 1 is a perspective view showing a power plug adapter

according to the present invention, Figure 2 is a disassembled perspective view of the power plug adapter according to the present invention, Figure 3 is a disassembled perspective view of upper and lower adapters of the power plug adapter according to the present invention, and Figure 4 is an engagement section view of the power plug adapter according to the present invention.

The power plug adapter according to the present invention comprises: an upper adapter 10 to which terminals 6 and 8 of power plugs 2 and 4 are inserted; and a lower adapter 12 rotatably connected with the upper adapter 10 and fitted into a receptacle (not shown).

The upper adapter 10 includes: an upper body 18 formed as a disc shape having a certain thickness and provided with a hinge hole 16 penetrating at the center of the upper body for inserting a hinge shaft 14; connection terminals 22 fitted-coupled to a terminal insertion groove 20 formed at the upper surface of the upper body and to which the terminals 6 and 8 of the power plugs 2 and 4 are connected; and input terminals 24 respectively connected to the connection terminals 22 and mounted at the lower surface of the upper body 18.

A cover 26 for preventing the connection terminals 22 from being deviated is coupled to the upper surface of the upper body 18. The cover 26 includes : an insertion hole 28 for inserting the terminals 6 and 8 of the power plugs 2 and 4; stopping protrusions 30 formed at both sides of the cover 26; a stopping groove 32 formed at the upper surface of the upper body 18. Herein, when the stepping protrusions 30 are fitted into the

stepping groove 32 thereby to couple the cover 26 to the upper body 18.

The connection terminals 22 are integrally composed of a first connection portion 34 for inserting the bar-type terminal 6 when the terminal 6 of the power plug 2 is a bar-type, and a second connection portion 36 for inserting the plate type terminal 8 when the terminal 8 of the power plug 4 is a plate-type.

The first connection portion 34 is formed as a cylindrical shape having one opened side, and the second connection portion 36 is extending from the first connection portion 36 integrally and is formed as a rectangular shape having a certain space and one opened side so that the plate-type terminal 8 can be inserted.

The connection terminals 22 are fitted into the terminal insertion groove 20 formed at the upper body 18, and lower surfaces thereof are connected to the input terminals 24. The connection terminals 22 have a structure that either the bar-type terminal 6 or the plate-type terminal 8 can be selectively inserted.

The lower adapter 12 includes : a lower body 40 disposed at the lower portion of the upper adapter 10; a hinge bar 14 coupled to the center of the lower body 40 and inserted into the hinge hole 16 of the upper body 18, for supporting the upper body 18 to be relatively rotated with the lower body 40; two terminal bars 42 fitted-coupled to the lower body 40 and thus to be inserted into a receptacle (not shown); and contact terminals 44 respectively connected to said two terminal bars 42 and attached to the upper surface of the lower body 40, for connecting a power source by

being in contact with the input terminals 24.

The lower body 40 includes two penetration holes 52 through which the terminal bars 42 are penetrated; the hinge bar 14 inserted and fixed to the center thereof; and ground plates 54 mounted at an outer surface thereof.

A spring 46 is interposed at an outer circumferential surface of the hinge bar 14, one side of the spring 46 is supported at the hinge hole 16, and another side of the spring 46 is supported at a fixed ring 48 fixed at an upper surface. of the hinge bar 42, thereby providing an elastic force for pushing the upper adapter 10 downwardly. According to this, the upper adapter 10 and the lower adapter 12 come in contact with each other with a certain elastic force.

The contact terminal 44 is formed as a semi-circular arc shape thus to be attached to an upper surface of the lower adapter 12, and comes in contact with the input terminal 24 mounted at a lower surface of the upper adapter 10 thus to be electrically connected to each other.

A power ON/OFF unit for turning ON/OFF a power by connecting or separating the input terminal 24 and the contact terminal 44 when the upper body 18 is relatively rotated against the lower body 40 is formed between a lower surface of the upper body 18 and an upper surface of the lower body 40.

As shown in Figures 5 and 6, the power ON/OFF unit includes : first grooves 60 formed at an upper surface circumference of the lower body 40 with certain interval and depth; second grooves 62 respectively formed

between the first grooves 60 with a depth shallower than that of the first grooves 60; and protrusions 64 formed at a lower surface circumference of the upper body 18 with a certain interval thus to be selectively inserted either into the first grooves 60 or into the second grooves 62.

That is, the power ON/OFF unit performs a relative rotation of the upper body 18 and the lower body 40, and according to this, if the protrusions 64 formed at the upper body 18 are inserted into the first grooves 60, the input terminals 24 are in contact with the contact terminals 44 thereby to connect a power. Also, if the power ON/OFF unit rotates the upper body 18 again thus to insert the protrusions 64 into the second grooves 62, the input terminals 24 are separated from the contact terminals 44 thereby to shield a power.

Operation of the power plug adapter according to the present invention will be explained as follows.

First, in case of using the power plug 2 having the bar-type terminal 6, the bar-type terminal 6 is inserted into the first connection portion 34 of the connection terminal 22. Also, in case of using the power plug 4 having the plate-type terminal 8, the plate-type terminal 8 is inserted into the second connection portion 36 of the connection terminal 22. That is, since both the bar-type terminal 6 and the plate-type terminal 8 can be used, a usage extent can be expanded in the present invention.

Under a state that the terminals 6 and 8 of the power plugs 2 and 4 have been inserted into the first and second connection portions 34 and 36, if the terminal bars 42 of the power plug adapter are inserted into the

receptacle, a power connection of the power plugs 2 and 4 is completed.

At this time, the protrusions 64 of the upper body 18 are inserted into the first grooves 60 of the lower body 40 and thus the input terminals 24 come in contact with the contact terminals 44, thereby supplying a power to the power plugs 2 and 4.

On the contrary, in order to turn off a power, the upper body 18 and the lower body 40 are relatively rotated. According to this, the protrusions 64 of the upper body 18 are inserted into the second grooves 62 and thus the input terminals 24 are separated from the contact terminals 44, thereby shielding a power to the power plugs 2 and 4.

INDUSTRIAL APPLICABILITY As so far described, according to the present invention, The power plug adapter according to the present invention can be applied regardless of the kinds of a terminal of a power plug (a bar-type terminal, a plate-type terminal), thereby enabling to expand the usage extent. Also, a power is turned on/off by relatively rotating the upper body and the lower body of the power plug adapter thereby to have a convenience in using.