Patent Publication Number: US-9887493-B2

Title: Electric plug

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/KR2016/008136, filed on Jul. 26, 2016, which claims priority to Korean Application No. 10-2015-0108439, filed Jul. 31, 2015. The entire disclosures of each of the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an electric plug and, more particularly, to an electric plug, which can be easily disconnected from an outlet. 
     BACKGROUND ART 
     Generally, an electric plug is provided to the end of a cord, which is connected to an electric appliance, as a kind of electric wiring mechanism and serves as a connection mechanism to be used to be plugged into an outlet. In general, electricity coming into a home or a factory is connected to an outlet, and the plug of an electric appliance is plugged into the outlet so as to supply electric power to the electric appliance. Herein, the plug has two pins (electrical connecting rods) fixed to a connection part for the outlet, for example, a plug body part and connected to a cord, such that the pins are inserted and fixed into the holes of the outlet to supply electric power to the electric appliance. Meanwhile, In the case of an electrical appliance, of which plug is repeatedly plugged in a home outlet, such as home appliances, the plug must be easily removable from the outlet. 
     However, it is considerably inconvenient to remove a plug that is strongly plugged into an outlet and, furthermore, the plug can be easily separated with strong force (generally 15 kgf for adults) to hold and pull the plug body part by hand. Herein, human plug-gripping force is less than plug-pulling force. When pulling a plug, it is necessary to use stronger pulling force than the plug-gripping force. Therefore, it is not easy to pull out a plug that is tightly plugged into an outlet for women, children and elderly people with weak hand force. 
     Therefore, in order to disconnect such a plug, which is strongly plugged into an outlet, people usually hold the outlet with one hand and hold the plug with the other hand and then pull out the plug, or people pull out a plug cord. Therefore, it is likely to break the outlet or the plug, or the electrical connection thereof. 
     Meanwhile, In order to solve these problems, there has been suggested a product designed to attach a ring-shaped handle to the plug such that the plug can be easily pulled out by pulling the ring-shaped handle.  FIG. 1  is a view for illustrating a prior art electric plug having such a ring part. However, the prior art electric plug still has inconvenience that, when pulling out the plug having a ring part, people have to pull the plug while holding the outlet with one hand. In addition, the ring part is likely to be broken in use. Therefore, fundamental problems still remains unsolved, and it is necessary to develop an electric plug which can easily be detached from an outlet with small force. 
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present invention has been made in an effort to solve the above-mentioned problems occurring in the prior arts, and it is an object of the present invention to provide an electric plug that is easy to be separated from an outlet with small force, thereby ensuring convenience in use. 
     The objects of the present invention are not limited to the above-mentioned object, and other objects not mentioned may be clearly understood by those skilled in the art from the following description. 
     Technical Solution 
     In order to solve the above-mentioned problems, the present invention provides an electric plug, including a body part having a reception part, pins inserted and fixed in one surface of the body part, and a detachment part provided to the reception part, wherein the detachment part includes a gear stick and a handle part rotating while being engaged with the gear stick. 
     In addition, the present invention provides the electric plug, in which the reception part includes a penetration part penetrating the body part, and the penetration part includes an upper opening part at one side of the body part and a lower opening part at the other side of the body part, such that a part of the handle part is exposed through the upper opening part and a part of the gear stick is exposed through the lower opening part. 
     Besides, the present invention provides the electric plug, in which the handle part includes: a serrated part engaged with the gear stick so as to rotate; a rotation shaft provided to the serrated part; and a press part extended from one side of the serrated part, wherein the handle part is individually provided at both sides of the gear stick with respect to the center of the gear stick. 
     Furthermore, the present invention provides the electric plug, in which the gear stick includes: a gear shaft; a gear part formed on a portion of the outer circumferential surface of the gear shaft and engaged with the serrated part; and a support part formed on the outer circumferential surface of the gear shaft, wherein the gear part has a plurality of gear protrusions formed to be perpendicular to the lengthwise direction of the gear shaft and provided at a uniform interval along the lengthwise direction of the gear shaft. 
     In addition, the present invention provides the electric plug, in which the gear shaft and the serrated part rotation shaft are provided to be orthogonal to each other, and support pins are inserted into the serrated part rotation shaft so as to be fixed in the body part. 
     Besides, the present invention provides the electric plug, in which the press part further includes a display part formed at one end part thereof so as to identify a coupling state with respect to an outlet. 
     Advantageous Effects 
     As described hereinabove, according to the present invention, the plug can be disconnected from an outlet using only one hand, and is thus convenient to use. 
     In addition, according to the present invention, the electric plug can be separated with small force and thus it is less likely to leave the plug in the outlet, thereby reducing power consumption. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view for illustrating a prior art electric plug. 
         FIG. 2  is a perspective view for showing an electric plug according to an embodiment of the present invention. 
         FIG. 3  is a front view for showing an electric plug according to an embodiment of the present invention. 
         FIG. 4  is an exploded view for showing an electric plug according to an embodiment of the present invention. 
         FIG. 5  is an exploded view for showing a detachment part of an electric plug according to an embodiment of the present invention. 
         FIG. 6  is a view for showing a detachment part of an electric plug according to an embodiment of the present invention. 
         FIG. 7  and  FIG. 8  are views for showing the use states of an electric plug according to an embodiment of the present invention, in which the process for separating the electric plug from an outlet is illustrated. 
         FIG. 9  and  FIG. 10  are views for showing the use states of an electric plug according to an embodiment of the present invention, in which the process for coupling the electric plug to an outlet is illustrated. 
         FIG. 11  is a view for illustrating an assembly type detachment part for an electric plug according to an embodiment of the present invention, and 
         FIG. 12  is a view for illustrating an electric plug, to which an assembly type detachment part is applied according to an embodiment of the present invention. 
     
    
    
     MODE FOR INVENTION 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     First,  FIG. 1  shows a prior art electric plug. In general, an electric device is connected to a cord with a plug for supplying electricity, wherein the plug is plugged into an outlet to supply electricity. It is not so difficult to put the plug into an outlet, but when the pins of the plug are firmly plugged into the outlet, it is difficult to pull out the plug. 
     Particularly, the plug, which is firmly plugged into an outlet, has to be separated only by the pulling force of a hand. Therefore, it is difficult to pull out the plug in case of women, children and elderly people with weak grip. In order to disconnect such a plug, which is firmly plugged into an outlet, people usually hold the outlet with one hand and hold the plug with the other hand, and then shake the plug up and down with the both hands. Also, people pull out the plug cord during the detachment process. Therefore, a failure such as the break of the electrical connection of the plug and the like may occur. 
     Therefore, in order to solve the inconvenience, there has been suggested an electric plug with a ring part  40 , as shown in  FIG. 1 . Such a plug includes a body part  10 , pins  20  provided for the electrical connection with respect to an outlet, a connection part  30  connected to a cord, and the like. However, if the plug is disconnected by pulling the ring part  40 , there is still the inconvenience of holding the outlet with one hand and pulling the plug body part with the other hand even though there is no failure in the code line itself. Furthermore, since a user has to put his finger in the ring part  40  and pull the ring part  40  with that finger, it can be hard on the user. Besides, due to the structural features of the ring part  40 , there is a concern that if the user plugs and unplugs the plug from time to time, the ring part might have been broken. 
     Therefore, according to preferred embodiments of the present invention, there is provided an electric plug, which can be detached even when only one hand is used and can be easily separated from the outlet even with small force. 
       FIG. 2  is a perspective view of an electric plug according to an embodiment of the present invention,  FIG. 3  is a front view of the electric plug and  FIG. 4  is an exploded view of  FIG. 3 . As shown in  FIG. 2  to  FIG. 4 , an electric plug  100 , according to an embodiment of the present invention, includes a body part  110 , pins  120  inserted into one surface of the body part so as to be fixed therein, and a detachment part  200  provided to the body part. Furthermore, the body part  110  includes a connection part  130  provided at one side thereof for the connection of a cord line, and the body part  110  includes a reception part  111  for receiving the detachment part  200 . 
     Besides, the reception part  111  is formed with a penetration part  112  formed penetrating the body part  110  so as to communicate with the reception part  111 . As shown in  FIG. 4 , the penetration part  112  includes an upper opening part  112   a  penetrating the upper portion of the body part  110  in the reception part  111  and a lower opening part  112   b  penetrating the lower portion of the body part in the reception part  111 , wherein the upper opening part  112   a  and the lower opening part  112   b  are connected to each other and the lower opening part  112   b  is formed in one surface of the body part  110 , into which the pins  120  is inserted and fixed, that is, the lower surface of the plug body part  110 . 
     The detachment part  200 , which is provided to the reception part  111 , is provided in a state, in which a part of the upper portion of the detachment part  200  is provided to be protruded upwards through the penetration part  112   a  and a part of the lower portion of the detachment part  200  is assembled to be protruded downwards through the lower opening part  112   b.    
       FIG. 5  is an exploded view for showing a detachment part for an electric plug according to an embodiment of the present invention, and  FIG. 6  is a perspective view for showing the detachment part, which is assembled. The detachment part  200  includes a gear stick  210  having a gear part  212  formed on the outer circumferential surface thereof, and one pair of handle parts  220  for rotating in engagement with the gear stick  210 . 
     The gear stick  210  includes a gear shaft  211  in a linear shape, a gear part  212  formed on a portion of the outer circumferential surface of the gear shaft  211 , and a support part  213  formed on the outer circumferential surface of the gear shaft  211  at the lower portion of the gear part  212 . 
     In addition, each of the handle parts  220  includes a serrated part  221  for rotating in engagement with the gear part  212 , and a press part  223  extended outwards in the upward direction from the serrated part  221 , wherein the handle part  220  is supported so as to rotate with respect to a support pin  230 , which is inserted into a support hole  222 . The support pin  230  is inserted into the support hole  222 , and the support pin  230  acts as a rotation shaft for the rotation of the serrated part  221 , thereby supporting the handle part  220  in the plug body part  110  so as not to escape therefrom. 
     In addition, the gear shaft  211  of the gear stick  210  is provided in a vertical state and the support pin  230  of the serrated part  221  is provided in a horizontal state. The gear part  212  is formed on a part of the outer circumferential surface of the gear shaft and engaged with the serrated part  221  of the handle part  220 . Therefore, in a state, in which the gear part  212  is engaged with the serrated part  221 , the gear part  212  is interlocked with the serrated part  221  and moves together with the serrated part  221  according to the movement of the serrated part  221 , wherein the rotational motion of the handle part  200  can be converted into the linear motion of the gear stick  210 . 
     That is, if the serrated part  221  carries out rotational motion with respect to the support pin  230 , power is transmitted through the gear part  212 , which is engaged with the serrated part  221  such that the gear shaft  211  carries out linear motion in the vertical direction. In addition, it is preferable that the handle part  220  includes one pair of handle parts symmetrically arranged in the right and left directions as shown in the drawings. 
     Meanwhile, as mentioned hereinabove, the upper portion of the detachment part  220  is provided in the upper opening part  112   a  in a state, in which the upper portion of the detachment part  220  is exposed upwards from the body part  110 , and the lower portion of the detachment part  220  is protruded to the outside of the body part  110  through the lower opening part  112   b  or re-inserted into the body part  110 . That is, the upper end portion of the press part  223  of the handle part  220 , which forms the upper portion of the detachment part  200 , is in the state of being protruded from the plug body part  110  and exposed upwards. Therefore, a user can easily pull out the plug, which is inserted into an outlet, by manipulating the exposed press part  223  by hand. 
     In addition, the lower end portion of the gear shaft  211 , which forms the lower portion of the detachment part  200 , is protruded downwards from the body part  110  through the lower opening part  112   b . When plugging the plug into an outlet, the lower end of the gear shaft  211  is inserted to the inside of the lower opening part  112   b . To the contrary, when unplugging the plug from an outlet, the one end of the gear shaft  211  is protruded to the outside of the lower opening part  112   b , wherein the operation principle will be described hereinafter with reference to  FIG. 7  and  FIG. 8 . 
     According to the embodiment of the present invention, the gear stick  210  carries out linear motion in the vertical direction in the lower opening part  112   b  in a state, in which the gear stick  210  is inserted in the reception part  111 . Therefore, it is preferable that the shape of the cross-section of the gear stick  210  is formed of a shape and a diameter, which are similar to those of the cross-section of the lower opening part  112   b.    
     Besides, according to the embodiment of the present invention as shown in  FIG. 5 , even though the gear stick  210  and the lower opening part  112   b  are shown having a rectangular sectional shape, in the present invention, the sectional shapes of the gear stick and the lower opening part are not limited to such a rectangular shape but the gear stick and the lower opening part may, of course, be provided in a circular or polygonal structure as shown in the embodiment of  FIG. 6 . 
     In addition, in order to enable a part of the lower end of the gear shaft  211  of the gear stick  210  to be inserted to the inside of the lower opening part  112   b  and carry out the linear motion in the axial (vertical) direction, the cross section of the gear shaft has to be smaller than the cross section of the lower opening part  112   b . Herein, since the gear part  212 , which is protruded outwards from the gear shaft  211 , is formed on the outer circumferential surface of the gear shaft  211  and the lower end portion of the gear part  212  is inserted to the inside of the lower opening part  112   b , for example, a width d 1  of the gear shaft  211  is formed to be smaller than a width D 1  of the lower opening part  112   b.    
     Since the gear shaft  211  may shake or be misaligned within the lower opening part  112   b , the support part  213  may be further provided on the outer circumferential surface of the gear shaft  211  in the present invention. 
     The support parts  213  are formed to be extended outwards at both sides of the gear shaft  211  so as to slide in contact with the inner circumferential surface of the lower opening part  112   b  at the side surfaces thereof when the vertical movement of the gear shaft  211 . Therefore, the support parts  213  serve to support the gear shaft  211  in the lower opening part  112   b  such that the gear shaft  211  can move accurately in the axial (vertical) direction without shaking in the lower opening part  112   b.    
     In addition, a holding protrusion  140  may be formed on the inside of the lower opening part  112   b , where the support part  213  slides. This holding protrusion  140  is to limit the lower end movement of the gear shaft  211 . That is, as described hereinabove, when the lower end portion of the gear shaft  211  moves in the vertical direction while sliding in the lower opening part  112   b , the end portion of the gear shaft  211  is protruded out of the end portion of the lower opening part  112   b  or inserted into the lower opening part  112   b . With respect to the movement of the gear shaft  211 , the holding protrusion  140  is held on the top surface of the support part  213 , which is formed on the gear shaft  211 , and thus serves to support the gear shaft  211  such that the gear shaft  211  does not move to the outside of the lower opening part  112   b  any more. 
     Meanwhile, even though the support part  213  may be provided in the shape of a holding protrusion as mentioned above in the case where the gear stick has a rectangular sectional shape as in the above-mentioned embodiment, it is also possible to provide a ring-shaped support part  213 ′ as shown in the embodiment of  FIG. 6 . 
     According to the embodiment of the present invention, as shown in  FIG. 6 , it can be noted that the sectional shape of a gear stick  210 ′ may be formed in a rectangular shape, and thus the shape of a gear part  212 ′ and a support part  213 ′ may also be formed in a ring shape along the periphery of the gear stick  210 ′. In this case, of course, even though not illustrated, the penetration part  112  of the plug body part may also have a circular sectional shape, corresponding to the shape of the gear stick  210 ′. 
     Next, the handling of the electric plug according to an embodiment of the present invention will be described hereinafter.  FIG. 7  and  FIG. 8  are views for showing the use states of an electric plug according to an embodiment of the present invention, in which  FIG. 7  shows a state, in which the electric plug is plugged in an outlet, and  FIG. 8  shows a state, in which the electric plug is separated from the outlet. 
     In order to separate the plug from an outlet  1 , the electric plug plugged into the outlet can be pulled out by manipulating the one pair of handle parts  220 , which are provided at both sides of the gear stick  210  and protruded upwards outside of the plug body part  110 . As shown in  FIG. 7 , in a state, in which the plug is plugged in the outlet  1 , the lower end portion of the gear shaft  211  of the gear stick  210  is in an inserted state in the lower opening part  112   b.    
     In order separate the plug from the outlet in the above state, the press parts  223  of the one pair of handle parts  220  are pressed from the outside to the inside by hands. For example, if the one pair of press parts  223  of the handle parts  220  are held and pressed by the thumb and the index finger, then the upper end portions of the one pair of press parts  223  come close to each other and thus the serrated parts  221 , which are formed at the lower portions of the press parts  223  rotate with respect to the support pins  230 . 
     In addition, considering the rotation directions of the one pair of serrated parts  221 , as shown in  FIG. 8 , 
     when viewed from the front surface of the plug, the left serrated part with respect to the gear shaft  211  rotates in the clockwise CW direction and the right serrated part rotates in the counterclockwise CCW direction. Therefore, as the one pair of serrated parts  221  rotate, the gear part  212 , which is engaged with the serrated parts  221 , carries out linear motion in the downward direction in association with the serrated parts  221 . 
     Therefore, the gear stick  210  moves in the downward direction in the lower opening part  112   b  provided in the plug body part  110  and thus the lower end portion of the gear shaft  211  of the gear stick  210  is protruded to the outside of the lower opening part  112   b . Therefore, the lower end portion of the gear shaft  211 , which is protruded out of the bottom surface portion of the plug body part  110 , pushes the top surface of the outlet  1 , which is in contact with the plug, such that the plug pins  120  are released from the outlet. 
     When pulling out the plug as mentioned above, the support part  213  provided to the outside of the gear shaft  211  is held on the holding protrusion  140  provided to the inside of the lower end portion of the lower opening part  112   b , thereby stopping the downward movement of the gear shaft  211 . Furthermore, a display part  224  for the identification of a coupling state with respect to an outlet may be further provided at the upper end of the press part  223 , which is protruded upwards outside of the plug body part  110 . The display part  224  is to an element provided with appropriate characters or symbols such that a user can visually recognize the states of the handle parts  220 . 
     Next, a process of plugging the electric plug of the present invention into an outlet will be described. First, as shown in  FIG. 9 , in a state, in which the electric plug  100  has been disconnected from the outlet  1 , the one pair of press parts  223  at the upper ends of the handle parts  220  are in a closed state and the lower end portion of the gear shaft  211  of the gear stick  210  is in the state of being protruded downwards out of the lower opening part  112   b  and exposed below the plug body part  110 . 
     In addition, if a user connects the plug into the outlet  1  by holding the plug body part  110 , as shown in  FIG. 10 , then the top surface of the outlet  1 , which comes into contact with the plug, pushes the protruded lower end of the gear shaft  211  in the upward direction and the plug pins  120  are inserted into the outlet  1 , such that the plug is plugged into the outlet  1 . As described hereinabove, the plug is used in a state, in which the plug body part  110  is coupled in the outlet, and the operation of the detachment part  200  when the plug is separated from the outlet is the same as mentioned above. 
       FIG. 11  is a view for illustrating an assembly type detachment part  300  according to another embodiment of the present invention, and  FIG. 12  is a view for illustrating an electric plug, to which an assembly type detachment part of  FIG. 11 . An electric plug  100 ′ according to this embodiment of the present invention can be formed by carrying out injection molding such that a reception part  111 ′ for the insertion of the assembly type detachment part  300  is included in a plug body part  110 ′, and then inserting the assembly type detachment part  300  into the reception part  111 ′. 
     The assembly type detachment part  300  can be said to be substantially the same as the detachment parts in the above-mentioned embodiments of the present invention and may further include a housing  350 , which is inserted to the inside of the electric plug  100 ′, and a cover  360 . The gear stick  310  and the handle parts  320  are assembled into the housing  350 . Furthermore, the housing  350  may include a first opening part  351  provided at the upper portion thereof for the manipulation of the press parts  323  of the handle parts  320  and a second opening part  352  provided at the lower portion thereof for the protrusion of the lower end portion of the gear shaft  311  of the gear stick. The other constituent elements in this embodiment are the same as those of the detachment part  200  as mentioned above, and thus detailed description thereof will be omitted. 
     As shown in  FIG. 12 , the plug body part  110 ′ includes the reception part  111 ′ for receiving the assembly type detachment part  300  including the housing  350  and the cover  360  as mentioned above. Furthermore, for the operation of the detachment part  300  assembled in the reception part  111 ′, the plug body part  110 ′ has to include opening parts provided at the upper part portion and the lower portion thereof. The body part  110 ′ may further include a cap  150  provided at the upper portion thereof so as to protect the detachment part. For example, as shown in  FIG. 12 , the assembly type detachment part  300  can be inserted to the inside of the reception part  111 ′ by opening the cap  150 , which is hinge-coupled to the upper portion of the body part  110 ′. Herein, the lower end portion of the gear shaft  311  of the assembly type detachment part can be protruded through the opening part which is formed at the lower portion of the body part  110 ′. 
     As described above, while the present invention has been particularly shown and described with reference to the embodiments thereof, it will be understood by those of ordinary skill in the art that the above embodiments of the present invention are all exemplified and various modifications and improvements may be made therein without changing the essential characteristics and technical idea of the present invention. Therefore, it should be understood that the above described embodiments are illustrative in all aspects and not restrictive.