JP2006202590A - Power plug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power plug eliminating extra man-hour at manufacture, capable of stably exerting a dustproof property for a long time. <P>SOLUTION: The power plug 11 is provided with a blade fixing part 14 made of thermosetting insulator on which a pair of blades 12 to be inserted into a receptacle is planted, and a covered part 16 made of plastic insulator, and an inside first face 22 and an outside second face 23 are formed by a plug side contact face 21. Dust proof parts 24, 25 having grooves 26, 27 and an eave part 28 integrally molded with the covered part 16 are arranged respectively on upper part and lower part of the blade of the second face 23. The eave part 28 has a height protruding from a plug side contact face 21, and blocks the gap between an insertion face of the receptacle (not illustrated) and itself to prevent the intrusion of dust into the gap. Further, the eave part 28 contacts the insertion face and deforms when making the plug side contact face 21 closely contact the insertion face of the receptacle, and the deformed part is housed in the groove 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power plug connected to an outlet for power supply of an electric device, and more particularly to a power plug employing a dustproof structure.

  The power plug is used for supplying power to an electric device such as a television by being attached to an outlet disposed on a wall of a building. The power plug is attached to the outlet by inserting and fixing a pair of plug blades provided on the power plug side into the outlet of the outlet. In some cases, a grounding terminal on the power plug side is further inserted into the grounding outlet of the outlet.

  In the state where the power plug is attached to the outlet, it is necessary that the insertion surface provided with the outlet on the outlet side and the surface of the power plug facing the plug are in close contact with each other. If there is a gap between these surfaces, dust and dust (hereinafter collectively referred to as dust) enter the gap over a long period of time. At this time, even if the dust itself contains a conductive material, or even if the dust itself is insulative, the accumulated dust is moisture like a power plug attached to an outlet placed near the washstand. Depending on the case, it may become conductive. In such a case, the pair of blades of the power plug are electrically connected, and a weak current flows between them to form a carbonized conductive path (track). When the current flowing through the carbonized conductive path increases and this part generates heat to a high temperature, a situation may occur in which the power plug suddenly ignites. This is called tracking. When tracking occurs, a fire occurs in the worst case due to the power plug.

  In order to prevent such a fire accident, the material of the power plug has been developed to be more flame retardant. However, appliances are being used in large quantities in many places with more varied usage patterns. Therefore, the number of fire accidents caused by dust between the outlet and the power plug has not been reduced as a whole.

  Under such circumstances, some ideas have been proposed for preventing dust from accumulating as much as possible in the gap between the outlet and the power plug. In the first proposal, a pressing member that can be moved back and forth with respect to the plug insertion surface is disposed in a predetermined region including a portion where the plug blade protrudes from the power plug (for example, Patent Documents). 1).

  In the first proposal, even if a slight gap occurs between the plug insertion surface and the power plug facing surface (hereinafter referred to as a plug-side contact surface), the plug is provided on the power plug side. The reciprocating pressing member always presses the plug insertion surface. Therefore, the pressing member is brought into close contact with the insertion surface around the pair of plug blades of the power plug, thereby preventing dust from being accumulated between the pair of plug blades of the power plug.

  However, in the first proposal, a special mechanism in which a pressing member that can be moved forward and backward is built around the pair of plug blades on the power plug side is necessary. For this reason, the structure on the power plug side becomes complicated, which not only increases the cost of the power plug, but also makes it difficult to reduce the size of the plug itself.

Therefore, a ring-shaped sponge member having a predetermined thickness is attached to the peripheral portion of the plug-side contact surface on the power plug side, or the pair of plug blades protrudes from the peripheral portion of the plug-side contact surface of the main body portion of the power plug. A second proposal has been made in which a bellows-like cylindrical member is attached so as to protrude in the direction of the movement (see, for example, Patent Document 2).
JP 2000-195613 (paragraph 0006, FIG. 3) JP-A-7-122326 (paragraphs 0010 to 0012, FIGS. 2 to 4)

  However, in the method of attaching the sponge member so that it protrudes to the peripheral part of the power plug side contact surface in the second proposal, the power plug is connected to the outlet surface of the outlet by a finite thickness when the sponge member is compressed. Will always float from. Therefore, there is a problem that the amount and force with which the pair of plug blades of the power plug are sandwiched by the blade receiving metal fittings of the outlet becomes insufficient, and the power plug is easily removed from the outlet.

  Further, the sponge member often breaks and falls off due to aging. In such a case, the dust that has entered from the damaged part of the sponge member is stably held by the pair of plug blades of the power plug because the sponge member covers the periphery. Similarly, moisture is stably maintained. As a result, there is a problem that fire due to tracking is likely to occur due to breakage of the sponge member.

  In the second proposed method of attaching the bellows-shaped cylindrical member, the power plug and the outlet are brought into close contact with each other so that the tip end portion of the bellows-shaped cylindrical member is pressed against the insertion surface of the outlet. Therefore, the power plug is always lifted from the plug insertion surface by this thickness. For this reason, as in the case of the sponge member, there is a problem that the amount and force with which the pair of plug blades are clamped by the blade receiving bracket of the outlet becomes insufficient, and the power plug can be easily removed from the outlet. In addition, since the bellows-like cylindrical member is attached to the main body of the power plug, it takes additional man-hours and not only increases costs, but also the risk that the cylindrical member may come off the main body of the power plug after many years of use. There were many problems.

  Accordingly, an object of the present invention is to provide a power plug that does not require extra man-hours for manufacturing and that can stably exhibit a dustproof action for a long period of time.

  In the invention according to claim 1, (b) a plurality of conductive members protruding in the same direction at a spatial distance from each other so as to make electrical contact with the conductive member receiving metal fitting on the outlet side; A first member made of a relatively hard first resin that fixes the positional relationship between the conductive members; and (c) a relatively soft and elastic second member that molds the periphery of the first member. A plurality of conductive members that are integrally formed from the resin and that are orthogonal to the protruding direction of the plurality of conductive members and that face the surface on which the outlets of the plurality of conductive members provided in the outlet are disposed are provided. It has an eaves part that protrudes by a predetermined amount from the position where it should catch dust entering the conductive members from the contact surface, and this eaves part comes into contact with the surface provided with the insertion port. This deformed part when elastically deforming A gap portion for storing to and a second member disposed in the vicinity of the overhanging portion to the power plug.

  That is, in the first aspect of the present invention, the power plug includes a first member made of a relatively hard first resin, and a second member made of a relatively soft and elastic second resin that molds the periphery of the first member. A member is provided. The first member is configured to fix the mutual positional relationship of a plurality of conductive members protruding in the same direction at a spatial distance so as to be in electrical contact with the conductive member receiving metal fitting on the outlet side. . The second member includes an eaves portion formed integrally with the second member and a gap portion disposed in the vicinity of the eaves portion. However, the eaves portion is orthogonal to the protruding direction of the plurality of conductive members and is directed to the plurality of conductive members from the contact surface facing the surface where the plurality of conductive member insertion ports provided in the outlet are disposed. A predetermined amount protrudes from the position to receive the invading dust. The gap portion accommodates the deformed portion when the eaves portion comes into contact with the surface provided with the insertion port and elastically deforms. Accordingly, it is possible to achieve both the close contact of the power plug with the outlet and the effective prevention of dust intrusion into the plurality of conductive members when a gap is generated. Furthermore, since the eaves portion is formed integrally with the surrounding portion of the first resin with the second resin, it does not require extra man-hours for manufacturing, but also has a dustproof effect compared to materials such as sponge materials. It can be demonstrated stably for a long time.

  As described above, according to the present invention, the power plug includes the eaves portion formed integrally with the second member made of the second resin, which is relatively soft and rich in elasticity, and the elastically deformed portion thereof. Therefore, it is possible to achieve both adhesion to the outlet and prevention of dust intrusion. Further, since the eaves portion is formed integrally with the second resin, not only an extra man-hour is required for manufacturing but also a dustproof action can be stably exhibited for a long period of time.

  Hereinafter, the present invention will be described in detail with reference to examples.

  FIG. 1 shows a cross-sectional structure of a power plug in one embodiment of the present invention. The power plug 11 includes a metal plug blade 12 that is inserted into a blade holder of an outlet (not shown). The plug blades 12 are paired, but in this figure, the one arranged on the back side is not shown. The plug blade 12 is fixed in the vicinity of a cruciform base located inside the power plug main body 13 by a blade fixing portion 14 formed by molding a curable insulator. Further, the base exposed from the blade fixing portion 14 of the plug blade 12 is connected to an electric wire (not shown) of the power cord 15 by caulking. After the plug blade 12 and the power cord 15 are connected, the blade fixing portion 14 and the distal end portion of the power cord 15 connected thereto are molded with a plastic insulator to form the covering portion 16. The blade fixing portion 14, the covering portion 16, and the distal end portions of the power cord 15 constitute the power plug 11.

  FIG. 2 shows the power plug of this embodiment as viewed from the distal end side of the plug blade in the direction in which the power cord is drawn out. The plug-side contact surface 21 facing the plug insertion surface (not shown) includes a first surface 22 formed by the blade fixing portion 14 to which the pair of plug blades 12 and 12 are fixed, and a first surface formed by the covering portion 16. 2 planes 23. Among these, the 1st surface 22 comprises the complete plane which makes the direction orthogonal to the longitudinal direction of a pair of plug blades 12 and 12 a surface.

  On the other hand, the second surface 23 forms dust-proof portions 24 and 25 in the direction orthogonal to the width direction of each of the pair of plug blades 12 and 12 near the upper end and the lower end in FIG. 2, respectively. The area except for the first surface 22 forms a continuous plane. The dust-proof portions 24 and 25 have a structure in which a pair of grooves 26 and 27 are arranged in the longitudinal direction of each of the dust-proof portions 24 and 25 and an eaves portion 28 having a shape protruding from the extended surface of the first surface 22 is arranged therebetween. It has become. FIG. 1 shows a portion where the plug-side contact surface 21 and the respective dustproof portions 24 and 25 are arranged.

  FIG. 3 is an enlarged view of one of the dust-proof portions shown in FIG. 3 shows the dust-proof part 24 positioned on the upper side in FIG. 1, but the other dust-proof part 25 is symmetrical with respect to the dust-proof part 24 with the center point of the plug-side contact surface 21 shown in FIG. ing. Therefore, detailed illustration and description of the dustproof portion 25 are omitted. As shown in FIG. 2, the dust-proof portion 24 projects an eaves portion 28 between the pair of grooves 26 and 27. The blade fixing portion 14 has a staircase shape having a step 31.

  FIG. 4 shows a cross-sectional structure of the portion shown in FIG. 3 in a conventional power plug for reference. The plug-side contact surface 21 of the power plug 41 that faces the plug insertion surface (not shown) is completely flat, and the blade fixing portion 14 has a flat shape with no step as shown in FIG. ing.

  In the power plug 11 of the present embodiment shown in FIG. 3, the blade fixing portion 14 bites into the covering portion 16 by the level difference 31, and the upper left end 32 in the figure of this biting portion is at the base of the eaves portion 28. positioned. Specifically, the distance from the upper end of the plug blade 12 to the upper part of the stepped shape of the blade fixing portion 14 in the direction orthogonal to the length direction of the plug blade 12 is from the upper end of the plug blade 12 to the protruding end of the eaves portion 28. It is set to be slightly shorter than the interval. Further, in the eaves portion 28, the side surface where the groove 26 exists forms a surface substantially perpendicular to the plug-side contact surface 21, and stands out from the opposite side surface where the groove 27 exists.

  As a result, when the plug-side contact surface 21 of the power plug 11 is brought close to the insertion surface of the outlet (not shown) and the pair of plug blades 12 and 12 shown in FIG. 1 are inserted into the insertion port, at a certain point in time, The tip of the eaves portion 28 hits the insertion surface. The eaves part 28 is a part of the covering part 16, is formed of a plastic insulator, and is made of a flexible material. For this reason, the eaves portion 28 is bent toward the groove 26 as shown by an arrow 33. When the pair of plug blades 12, 12 are completely received in the insertion port, the eaves portion 28 is housed in the groove 26 in a state where the tip is slightly pressed against the entrance portion of the groove 26. Is done.

  In this embodiment, the upper left end 32 of the blade fixing portion 14 is located at the base of the eaves portion 28. For this reason, when the force in the insertion direction is applied to the eaves portion 28 from the outside, the repulsive force by the upper left end 32 is weaker on the side where the groove 26 is present than on the side where the groove 27 is present. . Thereby, the eaves part 28 is easily inclined from the base toward the side where the groove 26 exists, and the eaves part 28 is urged to deform in this direction.

  FIG. 5 shows a state in which the plug-side contact surface of the power plug is completely in contact with the plug-in surface of the outlet. The entire covering portion 16 is made of a plastic insulator. For this reason, even if the tip of the eaves portion 28 exists so as to partially overlap the plug-side contact surface 21, dust may accumulate between the plug-in surface 44 of the outlet 43 and the plug-side contact surface 21 of the power plug. No gaps occur. Further, since the eaves portion 28 is formed of a plastic insulator, the restoring force for returning to the original shape is relatively weak due to its flexibility. For this reason, after a pair of plug blades 12 and 12 shown in FIG. 1 are inserted into and fixed to a blade receiving bracket (not shown) of the outlet, the behavior of pulling out from the blade receiving bracket only by the restoring force of the eaves portion 28 is shown. There is no.

  FIG. 6 shows a state in which the power plug is slightly detached from the outlet due to some external force. In this state, the tip of the eaves portion 28 is in contact with the insertion surface 44 of the outlet 43. Moreover, the eaves portion 28 is warped by its elasticity. For this reason, not only is there no danger of dust falling to the pair of plug blades 12, 12, but even if water drops fall along the insertion surface 44 of the outlet 43, this is guided to the groove 26. This prevents the blades 12 and 12 from falling to the side.

  When the power plug 11 is further inclined from the state shown in this figure by a certain external force in the direction in which the plug-side contact surface 21 becomes horizontal, the pair of plug blades 12 and 12 are separated from a blade receiving bracket (not shown). break away. Therefore, power is not supplied to the power plug 11 at this time, and there is no risk of fire.

  By the way, in a state where the pair of plug blades 12 and 12 are slightly connected to the blade bracket, a relatively large gap is formed between the insertion surface 44 of the outlet 43 and the plug-side contact surface 21 of the power plug 11. May occur.

  FIG. 7 shows an example of such a situation. Even if a relatively large gap occurs between the insertion surface 44 of the outlet 43 and the plug-side contact surface 21 of the power plug 11, the eaves portion 28 protrudes in the direction of the outlet 43 and narrows the gap d. ing. In the power plug 11, the position of the blade receiving bracket with respect to the length of the plug blade 12 is regulated in advance so that there is no danger that a human finger contacts the plug blade 12 through this gap. In the power plug 11 of this embodiment, the eaves portion 28 blocks the finger even when trying to insert a finger into the gap d. Therefore, for example, even if an infant's finger tries to enter the gap, this can be prevented, and electric shock can be more reliably prevented.

  <First Modification of Invention>

  FIG. 8 shows the power plug according to the first modification of the present invention as viewed from the distal end side of the plug blade in the direction in which the power cord is drawn out. In FIG. 8, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. As is apparent from FIG. 8, in the first modification, a first covering portion 16A comprising a covering portion 16A disposed around a first surface 22 comprising a blade fixing portion 14 to which a pair of plug blades 12, 12 are fixed. A dustproof portion 24A is formed in a ring shape on the second surface 23A. The dustproof portion 24A is also composed of a pair of grooves 26A and 27A and an eaves portion 28A disposed therebetween.

  In the power plug 11A of the first modification as described above, the dust-proof portion 24A integrally formed as the covering portion 16A is made of a flexible plastic insulator. Therefore, when the power plug 11A is connected to an outlet (not shown), the eaves portion 28A is deformed by being pressed against the insertion surface of the outlet, and most of the protruding portion is accommodated in the groove 26A. The apex portion of the eaves portion 28A slightly overlaps the surface of the surrounding covering portion 16A, but since the covering portion 16A is made of a plastic insulator as in the previous embodiment, this prevents the close contact with the outlet. Never happen. In addition, since the tip portion of the eaves portion 28A is thin, it is easy to stretch when deformed so as to spread outward.

  Moreover, in the power plug 11A of the first modification, the dustproof portion 24A covers the periphery of the pair of plug blades 12 and 12 in a ring shape, so that dustproof and waterproofing measures from all directions are taken. Therefore, longer-term tracking measures can be taken.

  <Second Modification of Invention>

  FIG. 9 shows a cross-sectional structure of the power plug in the second modification of the present invention, and corresponds to FIG. 1 of the embodiment. Therefore, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the power plug 11B, unlike FIG. 1, a power cord 15 is extended in a direction orthogonal to the length direction of the plug blade 12 of the power plug body 13B, and the pair of plug blades 12 and the power cord 15 are orthogonal. Arranged in the direction. Further, the dust-proof portion 24 is disposed only in the vicinity of the end portion of the plug-side contact surface 21 opposite to the direction in which the power cord 15 is drawn out, and the position symmetrical to the plug blade 12 is a plane. Yes. That is, no dustproof part is provided at this location.

  The power plug 11B of the second modified example can suppress the height from the plug insertion surface than the power plug 11 in which the power cord extends on the opposite side of the plug-side contact surface shown in the embodiment, The power cord 15 can be kept along the wall or the like without being bent from the power plug main body 13B. In many cases, the power plug 11B is often connected to an outlet with the power cord 15 hung downward. Therefore, dust can be effectively prevented from entering only by providing the plug-side contact surface 21 with the dust-proof portion 24 disposed above the plug blade 12 in this state. Of course, a dustproof part can also be arranged near the end of the plug-side contact surface 21 on the side where the power cord 15 extends. Thereby, even if the power plug 11B is connected to the outlet upside down, tracking due to dust accumulation can be effectively prevented.

  In the embodiment and the first and second modified examples, the case where the eaves portion is not completely accommodated in the groove in a state where the power plug is brought into close contact with the insertion surface of the outlet is shown. As described above, it is possible to devise the size of the groove and to devise the length and shape of the eaves portion.

<Third Modification of the Present Invention>

  FIG. 10 shows a cross-sectional structure of the power plug according to the third modification of the present invention, and corresponds to FIG. 1 of the embodiment. Therefore, parts corresponding to those in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted as appropriate. The plug-side contact surface 21 of the power plug 11C forms a flat surface without any irregularities, and the dustproof portions 24 and 25 of the embodiment shown in FIG. 1 are not provided. On the other hand, in the vicinity of the tip of the covering portion 16C adjacent to the plug-side contact surface 21 of the covering portion 16C, a step 51 slightly protruding over the entire circumference is formed. A portion of the step 51 perpendicular to the width direction of the blade 12, that is, two step portions extending in a direction perpendicular to the figure, has a dustproof portion 24 </ b> C having a cross-sectional shape in which katakana “i” is reversed left and right, 25C is integrally formed with other portions of the covering portion 16.

  The dustproof parts 24C and 25C are placed on a step 51 extending in the width direction of the plug blade 12 and on the support 52 in a state inclined at a predetermined angle with respect to the longitudinal direction of the plug blade 12. It is comprised with the eaves part 28C of the shape. The eaves portion 28 </ b> C has a wedge shape whose thickness is reduced in a direction extending to the tip of the plug blade 12, and is inclined to the support column 52 so as to move away from the central axis of the plug blade 12 toward the wedge tip. It is shaped like that attached to. Further, a predetermined length portion including the wedge tip of the eaves portion 28 </ b> C protrudes from the virtual surface obtained by extending the plug-side contact surface 21 to the tip side of the plug blade 12.

  The power plug 11C of the third modification has the above configuration. Therefore, when the plug blade 12 is advanced in the direction in which the plug-side contact surface 21 is brought into contact with the insertion surface 44 in order to attach the power plug 11C to the outlet 43 shown in FIG. Like 28, it is deformed in a direction away from the plug blade 12. The column 52 also facilitates this deformation. As a result, the plug-side contact surface 21 can be brought into intimate contact with the insertion surface 44, and the state in which the tip of the eaves portion 28C is in intimate contact with the insertion surface 44 in this state can be used to prevent plug blades from dust and moisture. 12 can be protected.

  In the third modification, the two dustproof parts 24C and 25C are arranged on the covering part 16C. However, as in the first modification of the present invention, the outside of the plug-side contact surface 21 is surrounded. As a matter of course, it may be arranged over the entire circumference, or one of the two dustproof portions 24C and 25C may be omitted as in the second modification. Moreover, although the power plug provided with only a pair of plug blades as terminals has been described in the embodiment and the modification, the present invention can be similarly applied to a power plug provided with other terminals such as a ground terminal. it can.

It is sectional drawing showing the cross-section of the power plug in one Example of this invention. It is the top view which looked at the power plug of a present Example toward the direction where a power cord is drawn out from the front end side of a plug blade. It is principal part sectional drawing which expanded and showed one dustproof part shown in FIG. 1 of a present Example, and its cross-sectional structure of the periphery. It is principal part sectional drawing showing the cross-section of the location shown in FIG. 3 in the conventional power plug. It is principal part sectional drawing showing the state which the plug side contact surface of the power plug completely contacted the insertion surface of the outlet in the present embodiment. It is principal part sectional drawing showing the state which the power plug slightly pulled out from the outlet socket by some external force in a present Example. It is explanatory drawing showing a mode that the comparatively big clearance gap generate | occur | produced between the insertion surface of an electrical outlet, and the plug side contact surface of a power plug. It is the top view which looked at the power plug in the 1st modification of the present invention toward the direction where a power cord is drawn out from the tip side of a plug blade. It is sectional drawing of the power plug in the 2nd modification of this invention. It is sectional drawing of the power plug in the 3rd modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Power plug 12 Plug blade 13 Power plug main body 14 Blade fixing | fixed part 15 Power cord 16 Cover | cover part 21 Plug side contact surface 22 1st surface 23 2nd surface 24, 25 Dust-proof part 26, 27 Groove 28 Eave part 43 Outlet 44 Insertion surface 51 Step 52 Prop

Claims (5)

A plurality of conductive members projecting in the same direction at a spatial distance from each other so as to make electrical contact with the conductive member receptacle on the outlet side;
A first member made of a relatively hard first resin that fixes the positional relationship between the plurality of conductive members;
A plurality of the plurality of second resin formed integrally with a relatively soft and elastic second resin that molds the periphery of the first member, and perpendicular to the protruding direction of the plurality of conductive members. A predetermined amount protrudes from a contact surface provided with the plurality of conductive members facing the surface on which the insertion port of the conductive member is disposed to a position to receive dust entering the plurality of conductive members. And a gap portion that accommodates the deformed portion when the eave portion is elastically deformed in contact with the surface provided with the insertion port, in the vicinity of the eave portion. A power plug comprising: 2 members.   The plurality of conductive members are a pair of plug blades, and when the pair of plug blades are inserted into the insertion ports of the same height arranged on a vertical surface, the eaves portion is the contact surface. The power plug according to claim 1, wherein the power plug is disposed at least at a position higher than the insertion port, and the gap includes at least a groove provided immediately above the eaves of the contact surface.   The plurality of conductive members are a pair of plug blades, and the eaves portion is provided so as to surround the pair of plug blades on the contact surface, and the difference so as to surround the outside of the eaves portion. 2. The power plug according to claim 1, wherein a ring-shaped groove is formed on the insertion surface.   The plurality of conductive members are a pair of plug blades, and when the pair of plug blades are inserted into the insertion ports of the same height arranged on a vertical surface, the eaves portion is formed on the contact surface. The power plug according to claim 1, wherein the power plug is disposed so as to protrude upward from an upper end portion of the pair of plug blades, and the gap portion is a space above the upper portion.   The first member has a stepped shape having a step that is retracted by a predetermined length in a direction opposite to the protruding direction of the plug blade in a cross section cut parallel to the surface of the plug blade at an intermediate position between the pair of plug blades. The distance from the upper end of the plug blade to the upper portion of the step shape in the direction perpendicular to the length direction of the plug blade is slightly shorter than the distance from the upper end of the plug blade to the protruding end of the eaves portion. The power plug according to claim 2 or 3, wherein the power plug is positioned.

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