JPH08111258A - Power plug - Google Patents

Abstract

PURPOSE: To provide a power plug which can not only prevent electric shocks but also eliminate fear of getting shock when connection is performed and in which metal piece will not contact with a terminal piece in the connected condition by furnishing a plug body at its front face with a cylindrical cover which is arranged as capable of emerging and retracting and covers the projecting part of the terminal piece in the liberated state. CONSTITUTION: In the liberated state, the projecting part 3a of a terminal piece 3 from a plug body 1 is energized by a spring 6 and arranged as capable of emerging and retracting and the foremost part farther than a projection part 3b is covered with a transparent cylindrical cover 4 which is protruding farther than the body 1. When the body 1 is inserted into a power outlet 7, the terminal piece 3 is held pinchedly by a terminal 71 on the outlet 7 side, and also the foremost part of the cover 4 is contacted with the front face of the outlet 7. This configuration eliminates not only risk of electric shocks but also fear of shock at the time of connection, and in the connected condition, metal piece will not contact with the terminal piece.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a power plug,
More specifically, the present invention relates to a power plug having an electric shock prevention mechanism when connecting (or disconnecting) to an outlet.

[0002]

2. Description of the Related Art FIG. 10 shows a conventional general power plug X (two-pole type). In this conventional power plug X, two terminals are provided on the front surface 1a of the plug body 1. The tip sides of the pieces 3 and 3 are projected (projections 3b and 3b).
Then, in order to connect the power plug X to the outlet 7, the portion of the plug body 1 is pinched with a finger and each terminal piece 3, 3 is connected.
The protruding portions 3b, 3b of the plug into the insertion holes 70, 7 of the outlet 7.
This is done by plugging in zeros. In addition, outlet 7
On the inner side of each of the insertion holes 70, 70, the connection terminals on the power supply side (two contact plates as one set) are arranged,
When the power plug is connected to the outlet, the terminal piece projecting portions 3b and 3b are held by the connection terminals on the power source side while being pinched.

[0003]

By the way, in the conventional power plug X, the respective terminal piece projecting portions 3b, 3b are exposed in front of the plug body 1, and when the power plug X is connected to the outlet 7. In particular, especially for infants, there is a risk that the terminal piece projecting portions 3b, 3b may be accidentally inserted into the insertion holes 70, 70 of the outlet 7 while keeping their fingers in contact. As described above, when the terminal piece projecting portions 3b, 3b are connected to the connection terminals on the outlet 7 side with the fingers kept in contact with the terminal piece projecting portions 3b, 3b, an electric shock accident occurs. there were. Also, an adult plugs the power plug X into an outlet 7
Even when the connection operation is performed on each terminal piece protruding portion 3b,
When 3b is exposed, the terminal piece protrusion 3b,
There is a sense of anxiety that a finger may touch 3b and receive an electric shock. Furthermore, in this conventional power plug X, some gap (gap of about 1 to 2 mm) may occur between the front surface 1a of the plug body 1 and the front surface 7a of the outlet 7 even when connected to the outlet 7. Yes, thin (or thin) from the gap
There is a possibility that the metal piece may come into contact with the terminal piece projecting portions 3b and 3b, and in that case, there is a risk of electric shock or electric leakage.

In view of the above-mentioned problems in the conventional power plug, the present invention makes it possible to prevent the electric shock and the anxiety of electric shock when the power plug is connected to the outlet, and to connect to the outlet. It is an object of the present invention to provide a power plug in which a metal piece does not come into contact with a protruding portion of a terminal piece of the existing power plug.

[0005]

The present invention has the following constitution as means for solving the above problems. The power plug of the present invention uses a case-shaped plug body, and may be an assembly type in which the case-shaped plug body and the terminal piece are assembled with screws or the like, or a terminal piece in the plug body. It may be an integral type in which the base end side of is embedded. Further, the terminal piece may have two poles or three or more poles.

First, according to the first aspect of the present invention, in a power plug in which the tip side of the terminal piece is projected from the front surface of the plug body, a cylindrical cover body is provided on the front part of the plug body, and a protruding portion of the terminal piece is provided. Is installed so as to be retractable between a projecting position capable of covering the outside of the plug and a retracted position exposing the projecting portion, and the cover body is biased in the projecting direction by the biasing member with respect to the plug body.

In the power plug according to the first aspect of the present invention, the cover body may be a rectangular tube made of a hard material such as plastic. Further, it is desirable that the cover body is a single one and is formed in a size capable of collectively covering the outer sides of the respective terminal piece projecting portions.

Further, in the power plug according to claim 1 of the present application, the cover body may be made to project and retract in the plug body, or may be made to project and retract along the outer surface of the plug body. The cover body is installed in a state in which it is always biased in the protruding direction by a biasing member (for example, a spring), but a retaining mechanism for preventing the cover body from coming out of the plug body in the most protruding state. Should be provided. In the free state, the cover body is maintained at the projecting position where it can cover the outside of the terminal piece projecting portion by the biasing force of the biasing member, while pressing the front surface of the cover body biases the biasing member. It is possible to immerse the terminal piece to the immersive position where the protruding portion of the terminal piece is exposed against the force. The urging force of the urging member is set to be smaller than the holding force with which each terminal piece protrusion is pinched and held by the connection terminal on the outlet side when the power plug is connected to the outlet. , Even if the cover body is biased in the protruding direction, the power plug will not accidentally come out of the outlet.

According to the second aspect of the present invention, in the power plug in which the tip side of the terminal piece projects from the front surface of the plug body, the front surface of the plug body can cover the outside of the projecting portion of the terminal piece. The cover body is installed, and the cover body is configured to be expandable and contractible in a bellows shape and to be extended by self-elasticity in a free state. In the free state, the cover body is maintained in a position to cover the outside of the terminal piece projecting portion by the self-elasticity force, while pressing the front surface of the cover body resists the self-elasticity force and the terminals. It is designed so that it can be reduced to a position where the protruding portion is exposed. Also in the power plug according to claim 2 of the present application, when the power plug is connected to the outlet, the power plug does not accidentally come out of the outlet due to the self-elasticity of the cover body.

Further, in the invention of claim 3 of the present application, in the power plug of claim 1 or 2, the cover body is formed of a transparent material, and the position of the protruding portion of the terminal piece can be visually recognized through the transparent cover body. I am trying. Incidentally, claim 1 or 2
In the power plug of 1, the cover body can be formed of a non-transparent material. In that case, when the cover body is in a protruding state (or in an extended state), the terminal piece protruding portion on the outer surface of the cover body corresponds. It is advisable to add a point mark or a slit at the position so that the position of the terminal piece protrusion can be confirmed from the outside.

[0011]

In the power plug according to the first aspect of the present invention, when the cover body is in the free state, the cover body is biased by the biasing member to the projecting position, and the cover body covers the outside of the terminal piece projecting portion. ing. Also in the power plug according to the second aspect of the present invention, when the cover body is in the free state, the cover body extends by the self-elasticity, and the cover body covers the outside of the terminal piece protruding portion. As described above, in the power plugs according to claims 1 and 2, when the cover body is in the free state, the cover body covers the outside of the terminal piece projecting portion, so that the finger may come into contact with the terminal piece projecting portion. Absent. Also, when connecting the power plug to the outlet, the plug body may be pinched and supported by fingers, and the plug body may be pressed toward the outlet with the terminal piece protruding portion corresponding to the insertion hole of the outlet. Then, first, the front surface of the cover body comes into contact with the front surface of the outlet, and then the cover body is recessed (or reduced) in the plug body side, and at the same time, the terminal piece protruding portion enters the insertion hole of the outlet, and the terminal piece protruding portion is The connection terminal on the outlet side holds the pressure. In this state, the clamping force holding force by the connection terminal portion is larger than the urging force and self-elasticity force to the cover body, and the power plug is kept connected to the outlet even if the finger is removed from the plug body. It Further, in the state where the power plug is connected to the outlet as described above, the front surface of the cover body is pressed against the front surface of the outlet, and even if some gap is generated between the front surface of the plug body and the front surface of the outlet, the gap Is closed by the cover body, the terminal piece protruding portion is not exposed from the gap.

When the power plug connected to the outlet is pulled out by pinching the plug body with a finger,
The cover body automatically projects or extends, and the cover body covers the outside of the terminal piece projecting portion.

Further, according to the third aspect of the present invention, in the case where the cover body is made of the transparent material, even when the cover body covers the outside of the terminal piece projecting portion, the cover body is passed through from the outside. The terminal piece protrusion can be seen, and the work of aligning the terminal piece protrusion with the insertion hole on the outlet side becomes easy.

[0014]

In each of the power supply plugs according to claims 1 and 2, the cover body covers the outside of the protruding portion of the terminal piece in the free state. Therefore, when the power supply plug is connected to the outlet, the finger is used. Since it does not come into contact with the projecting portion, it is possible to reliably prevent the risk of electric shock due to contact with the projecting portion of the terminal piece, and it is possible to eliminate such anxiety of electric shock. Also, the cover body is
Since it can be retracted (or expanded and contracted) with respect to the plug body, even if the cover body is provided, there is no problem in connecting the power plug to the outlet. Further, in the state in which the power plug is connected to the outlet, even if there is a gap between the front face of the plug body and the front face of the outlet, the gap is closed by the cover body.
The metal piece does not come into contact with the projecting portion of the terminal piece inside the cover body, and there is an effect that the risk of electric shock or electric leakage due to the metal piece can be prevented.

Further, in the power plug of claim 3 of the present application,
Since the cover body is formed of a transparent material, the terminal piece protruding portion can be visually recognized from the outside of the cover body, and even if the outside of the terminal piece protruding portion is covered with the cover body, the power plug is The effect is that the work of connecting to an outlet can be performed without any problems.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 9, and FIGS.
7 is the same as the second embodiment, FIG. 8 is the same as the third embodiment, and FIG.
Shows the power plugs of the fourth embodiment. Further, in the present application, a power plug having a structure in which the tip sides of the terminal pieces 3, 3 are projected from the front surface 1a of the plug body 1 is targeted. In these embodiments, the terminal piece 3 used for the power plug may have two poles or an appropriate number of poles of three or more. In the following description, in the power plug of each embodiment, the side on which the protruding portion 3b of the terminal piece 3 projects is referred to as the front side, and the connecting side of the electric wire 8 is referred to as the rear side.

[0017] First, to describe the power plug Y ₁ of the first embodiment shown in FIGS. 1-5, the power supply plug Y ₁ of the first embodiment, the two terminal piece 3 from the front surface 1a of the plug main body 1 , 3 are projected, and a rectangular cylindrical cover body 4 for covering the outside of the projecting portions 3b, 3b of the terminal pieces 3, 3 is projected and retracted in the front and rear direction of the plug body 1 on the front surface 1a portion of the plug body 1. It is configured to include a biasing member 6 that is freely installed and that biases the cover body 4 in the protruding direction.

In the first embodiment, the plug body 1 is constructed by assembling a total of three case bodies (11, 12, 20). That is, the plug body 1 is composed of an upper case 11 and a lower case 12 which are vertically divided into two parts.
0 and an inner case 20 housed in the outer case 10. Outer case 10 (both upper and lower cases 11, 1
2) and the middle case 20 are molded of synthetic resin.

The outer case 10 includes upper and lower cases 11,
12 are combined by screws 9 to be integrated, but when the upper and lower cases 11 and 12 are combined, a space for accommodating the middle case 20 is formed inside the outer case 10, and A considerably large opening 15 is formed on the front side of the outer case 10. Further, notches are formed in the rear wall portions of the upper and lower cases 11 and 12, respectively, and the cord insertion hole 14 is configured by combining the notches.

In the central portion of the upper surface of the lower case 12 near the rear side,
The protrusion 17 for positioning the middle case 20 is integrally formed. The upper and lower cases 11 and 12 are attached to the protrusion 17.
The screw 9 is screwed into the front end side of the screw 9 in a state where they are combined.

The middle case 20 has a rectangular bottom wall 21 having a rear wall 22, a front wall 23, and left and right side walls 24, 24 integrally formed on an outer peripheral portion of the rectangular bottom wall 21. The inner case 20 is formed such that its size in front view is slightly smaller than the size of the front opening 15 of the outer case 10. A positioning hole 25 is formed in the bottom wall 21 at a central portion near the rear side thereof so as to be fitted into the protrusion 17 on the lower case 12 side.
Are formed. A notch 26 for inserting a cord is formed in the rear wall 22. On the front wall 23, each terminal piece 3, 3
Two insertion holes 27, 27 for inserting the tip portions (becoming protrusions) 3b, 3b, respectively, are formed.
The left and right side walls 24, 24 are recessed inward grooves 2 which are recessed inward for guiding an inward projection 43 of the cover body 4 which will be described later.
8 and 28 are formed respectively. Each groove 2
8 and 28 are continuously formed over a considerably long range from the rear end of the side wall 24 to a position near the front end. The front end of each groove 28 serves as a stopper 29 for preventing the cover body 4 from coming off, as will be described later. The voids in each groove 28 also serve as an installation space for installing a biasing member (coil spring) 6 described later.

In this embodiment, the cover body 4 is formed of a tubular body 41 made of a transparent material having a horizontally long rectangular shape and a predetermined length in a front view. Further, the cylindrical body 41 has an inside shape that is slightly larger than the outer shape of the middle case 20 in front view, and the outer shape of the cylindrical body is slightly smaller than the front opening 15 of the outer case 10.

Outward projections 42, 42 and inward projections 43, 43 projecting outward and inward are integrally formed at the rear end portions of the left and right side walls of the cover body 4, respectively. The inward projections 43, 43 correspond to the respective groove grooves 2 of the middle case 20.
It is inserted and slid in the inside of 8 and 28, respectively. The outward projections 42, 42 are for securing a space between the outer surface of the cover body 4 and the inner surface of the outer case 10 for installing the biasing member 6 as described later. .

As the biasing member 6, a coil-shaped spring is used in this first embodiment. A pair of left and right springs 6 are used.

Each of the terminal pieces 3 and 3 is formed in a thin plate shape, and the base end portion 3a side is fixed to the bottom wall 21 of the middle case 20 with a screw 30 and installed.

The power plug Y ₁ of the first embodiment shown in FIGS. 1 to 5 is assembled as follows. First, in the disassembled state of FIG. 4, the tip ends of the respective terminal pieces 3, 3 which become the protruding portions 3b, 3b are inserted from the inner side of the middle case 20 into the respective insertion holes 27, 27 of the front wall 23, and The base ends 3a, 3a of the terminal pieces 3, 3 are housed in the middle case 20. Next, the cover body 4 is fitted to the outside of the middle case 20 from the rear end side of the middle case 20 and slid forward. In this state, the base end portions 3a, 3 of the terminal pieces 3, 3 are
a is exposed upward from the upper open portion of the middle case 20. Next, the middle case 20 together with the cover body 4 and the springs 6 and 6 is fitted in the recessed grooves 28 and 28 of the middle case 20 on the rear end side of the cover body 4 with the respective springs 6 and 6. It is housed in the lower case 12. At this time, the positioning hole 25 on the side of the middle case 20 is externally fitted to the protrusion 17 on the side of the lower case 12 to position the middle case 20 in the lower case 12. At this time, the front surface of the lower case 12 and the front surface of the middle case 20 are flush with each other. Next, the base end portions 3a and 3a of the terminal pieces 3 and 3 and the bottom wall 21 of the middle case 20 are fastened to the lower case 12 with screws 30 and 30, respectively, and the lower case 12 and the middle case 20 are tightened.
And the terminal pieces 3 and 3 are integrated. At this time, the ends of the lead wires of the electric wire 8 are connected and fixed to the terminal piece base end portions 3a, 3a with the screws 30, 30. In this state, the cover body 4 is slidable in the front-rear direction with respect to the lower case 12 and the middle case 20.
Are the left and right rear end surfaces of the cover body 4 and the rear wall 13 of the lower case 12.
And the cover body 4 is urged forward by the elastic force of the springs 6 and 6. Next, after covering the upper case 11 with the upper part of the lower case 12, the upper case 11 and the lower case 12 are fastened and fixed with the screws 9, and the assembly of the power plug Y ₁ is completed.

The power plug Y assembled in this way
_{In 1} , the cover body 4 is biased forward by the springs 6 and 6, and when the cover body 4 is in the free state, the front end surface of the cover body 4 has the terminal pieces 3 as shown in FIGS. , 3 is projected from the tip of the tip a little (for example, about 1 to 3 mm). Therefore, the outer sides of the protruding portions 3b and 3b of the terminal pieces 3 and 3 are covered by the protruding portions of the cover body 4. The cover body 4 is urged forward by the spring 6, but when the cover body is in a free state, the inward projections 43, 43 on the cover body 4 side are provided with the concave groove 2.
The front end portions (stoppers 29, 29) of 8, 28 are abutted against each other, and the cover body 4 does not further project (pull out) forward.

The power plug Y _{1 is connected} to the outlet 7
When connecting to (FIG. 1 or FIG. 5), the plug body 1 is pinched with fingers, and each terminal piece protruding portion 3b, 3b is connected to the outlet 7
Corresponding to the insertion holes 70, 70 of. At this time, if the cover body 4 is made of a transparent material as in this embodiment, even if the cover body 4 covers the outside of the terminal piece projecting portions 3b, 3b, the cover body 4 is externally covered. The terminal piece protrusions 3b, 3b can be seen through the body 4, and the work of aligning the terminal piece protrusions 3b, 3b with the insertion holes 70, 70 on the outlet side becomes easy. Then, when the power plug Y ₁ is pushed into the outlet side, first, the front end surface of the cover body 4 comes into contact with the front surface of the outlet 7, and then the cover body 4 resists the resilience of the springs 6 and 6. The hollow portion 16 in the main body 1 is recessed inward (rearward), and at the same time, the terminal piece protrusions 3b, 3b are inserted into the insertion holes 70, 70 of the outlet 7.
The terminal piece protrusions 3b and 3b into the outlet 7.
The connection terminals 71, 71 on the side are held under pressure. In this state (state of FIG. 5), the connection terminals 71, 7
The holding force of the clamping force by one portion is larger than the spring biasing force to the cover body 4, and the power plug Y ₁ is kept connected to the outlet 1 even if the finger is removed from the plug body 1. Further, when the power plug Y ₁ connected to the outlet is pulled out by pinching the plug body 1 portion with fingers, the cover body 4 is automatically projected by the urging force of the springs 6 and 6, and the cover body 4 is removed. With terminal piece protrusion 3
It comes to cover the outside of b and 3b.

As described above, in the power plug Y ₁ , since the cover body 4 covers the outside of the terminal piece projecting portions 3b, 3b in the free state, when the power plug Y ₁ is connected to the outlet 7, the fingers are not touched. The terminal piece projecting portions 3b, 3b are not in contact with each other, so that the terminal piece projecting portions 3b, 3b are not contacted.
It is possible to surely prevent the risk of being touched with and being electrocuted, and also to eliminate such anxiety of being electrocuted. Further, since the cover body 4 is retractable (or expandable / contractible) with respect to the plug body 1, even if the cover body 4 is provided, there is no problem in connecting the power plug Y ₁ to the outlet 7. There is no. Furthermore, FIG.
As shown in FIG. 4, in the state where the power plug is connected to the outlet, even if there is a gap between the plug body front surface 3a and the outlet front surface 7a, the gap is closed by the cover body 4, Terminal piece projecting portions 3b, 3b
The metal piece does not come into contact with the metal piece, and the risk of electric shock, electric leakage, etc. due to the metal piece can be prevented.

In the power plug Y ₂ of the second embodiment shown in FIGS. 6 to 7, the plug body 1 has the base end portion 3 of each terminal piece 3, 3.
a and 3a are embedded, and a peripheral wall portion 19 is provided in a state in which voids 16 having predetermined intervals are provided on the upper, lower, left and right sides of the solid portion 18.
Is integrally molded. In addition, in the second embodiment, the cover body 4 that covers the outside of the terminal piece projecting portions 3b, 3b is installed so as to be able to appear and disappear in the annular space 16 of the plug body 1. Further, a retaining mechanism for the cover body 4 is provided between the cylindrical body 41 of the cover body 4 and the solid portion 18 of the plug body 1. That is, this removal mechanism forms the inward claws 44, 44 on the upper and lower walls of the rear end of the cover body 4 (cylindrical body 41), respectively, while the upper end of the solid portion 18 is
Outward claws 31 and 31 are formed on the lower surface, respectively, and when the cover body 4 is most protruded, the claws 44 and 31 on each side are engaged to prevent the cover body 4 from coming out. . In order to connect the plug body 1 and the cover body 4, if the rear end portion of the cover body (cylindrical body 41) is strongly pushed into the annular space 16 from the front side of the plug body 1, the cylinder body 41 is pressed.
Due to the elastic deformation, the claws 44, 44 on the cover body 4 side get over the claws 31, 31 on the plug body 1 side and enter the depth side. After that, the tubular body 41 elastically returns to engage the claws 44, 44 on the cover body 4 side with the claws 31, 31 on the plug body 1 side. In the power plug Y ₂ of the second embodiment, since the plug body 1 and the terminal pieces 3 and 3 are integrally formed, the work of assembling them is unnecessary.

In the power plug Y ₃ of the third embodiment shown in FIG. 8, the base end portion 3 of each of the terminal pieces 3, 3 is the same as in the second embodiment.
a and 3a are embedded in the plug body 1. Further, the cover body 4 is assembled so that it can slide back and forth outside the plug body 1. A front wall 45 is integrally formed with the cover body 4 (cylindrical body 41), and on the other hand, a front surface 1a of the plug body 1 is formed with a hole 32 having a considerably large depth toward the rear. The cover body 4 has a front wall 45 and a hole 32.
A spring 6 is provided between the cover body 4 and the bottom surface of the cover body 4.
Is urged in the protruding direction. Further, the cover body 4 is the cylindrical body 4
Inward claws 47, 47 provided at the rear end of the plug body 1
By engaging with outwardly facing claws 33, 33 provided at the tip of the plug, the plug body 1 is prevented from coming off. On the front wall 45 of the cover body 4, the terminal piece projecting portions 3b, 3b are provided.
There are formed openings 46, 46 for inserting the. In the power plug Y ₃ of the third embodiment, the cover body 4 is adapted to project and retract on the outside of the plug body 1 as indicated by reference numeral 4 ′, so that the configuration on the plug body 1 side is more than that of FIG. 6. It will be easy.

In the power source plug Y ₄ of the fourth embodiment shown in FIG. 9, the cover body 5 is replaced with a hard case and a bellows-shaped cylindrical body 51 made of a transparent material is adopted. This bellows-shaped cylinder 5
The plug 1 has a front surface 1a of the plug body 1 which can be expanded and contracted. Further, the bellows-shaped tubular body 51 is provided with a spring 52 for extension so that the cover body 5 has a self-elasticity. In the power plug Y ₄ of the fourth embodiment, when the cover body 5 is free,
As shown by the solid line in FIG. 9, the terminal piece protrusions 3b, 3
It extends to a position that covers the outside of b, and on the other hand, in the state of being connected to an outlet (terminal piece protrusions 3b, 3
b is clamped and held by the connection terminal on the outlet side)
The cover body 5 is adapted to be maintained in a contracted state as indicated by reference numeral 5 '. When the power plug Y ₄ is connected to an outlet and the power plug is removed, the cover body 5 is automatically returned to the extended state by its own elastic force.

In the respective power plugs of the second to fourth embodiments, those having the same reference numerals as those of the first embodiment have the same operation as the member, and the second to the second embodiments. The power plugs of the fourth embodiment also have the same effects as the power plug Y ₁ of the first embodiment.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view (sectional view taken along line I-I of FIG. 2) of a power plug according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is an exploded perspective view of the power plug of FIG.

5 is a state change diagram of FIG. 1. FIG.

FIG. 6 is a horizontal cross-sectional view of a power plug according to a second embodiment of the present invention.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a horizontal sectional view of a power plug according to a third embodiment of the present invention.

FIG. 9 is a horizontal sectional view of a power plug according to a fourth embodiment of the present invention.

FIG. 10 is a perspective view of a conventional power plug.

[Explanation of symbols]

Reference numeral 1 is a plug body, 1a is a front surface, 3 is a terminal piece, 3a is a base end portion, 3b is a protruding portion, 4 is a cover body, 5 is a cover body, 6 is a biasing member (spring), and 7 is an outlet.

Claims (3)

[Claims] 1. A power plug in which a tip side of a terminal piece (3, 3) is projected from a front surface (1a) of a plug body (1), the front surface (1a) portion of the plug body (1) being provided with: The cylindrical cover body (4) is provided with a projecting position capable of covering the outside of the projecting portions (3b, 3b) of the terminal pieces (3, 3) and a retracted position exposing the projecting portions (3b, 3b). The cover body (4) is urged by the urging member (6) toward the plug body (1) in a protruding direction, and the cover body (4) is in a free state. In the above, the power plug is characterized in that the cover body (4) is kept in the projecting position while being pushed into the plug body (1) to the retracted position by pressing the front surface of the cover body (4). 2. A power plug in which a tip side of a terminal piece (3, 3) is projected from a front surface (1a) of a plug body (1), the front surface (1a) portion of the plug body (1) being provided with: A cover body (5) capable of covering the outside of the protrusions (3b, 3b) of the terminal pieces (3, 3) is installed, and the cover body (5) is a bellows that is expandable and contractible in a free state. The cover body (5) is configured to extend by elastic force, and further, in a free state, the cover body (5) is maintained at a position to cover the outside of the terminal piece protrusions (3b, 3b), while the cover body (5) is maintained. 5) A power plug characterized in that the terminal piece projecting portions (3b, 3b) can be contracted to a position where they are exposed by pressing the front surface of 5). 3. The power plug according to claim 1, wherein the cover body (4, 5) is made of a transparent material.