JP2006049223A - Attachment plug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an attachment plug equipped with a core made of thermosetting resin and a blade cap resistant to tracking, excellent in reliability and economy, and improved in productivity by improving assembling workability. <P>SOLUTION: A blade cap 8 is directly and integrally molded in a core 9. Sleeves 80 of the blade cap 8 are formed in a right and left pair, and protruded from the front face of the core 9 when the blade cap 8 is integrally molded in the core 9. Further, the blade cap 8 is structured of polyamide resin, and blade retaining parts 81 for retaining plug blades 3A, 3B are provided at the rear end of the blade cap 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a double-structured insertion plug incorporating a core made of a thermosetting resin, and more particularly to an insertion plug in which a blade cap corresponding to tracking resistance is integrally formed as a core component. is there.

  Generally, a power cord is installed in an electrical device such as an electric appliance or OA device, and an insertion plug that is plugged into an outlet is provided at an end of the power cord. The plug is a plug body made of an insulating material, and a pair of plug blades made of a metal plate are attached. The plug plug is configured to supply electric power to electrical equipment by inserting the plug blade into the blade receiving hole of the outlet. ing. Various types of such plugs are known, and for example, a double structure having a core made of a thermosetting resin has been proposed. In this type of plug, a core is incorporated into the plug body by insert molding or the like, and the plug blade is held by the core. Thereby, the holding strength and heat resistance of the plug blade can be increased, and excellent safety can be ensured. Therefore, it is suitable for use in electrical equipment with high power consumption.

  By the way, when inserting the plug into the outlet, it is important to be able to smoothly insert the plug blade into the blade receiving hole of the outlet. For this reason, the external dimensions (thickness / width) of the plug blade are set slightly smaller than the blade receiving hole of the outlet. However, such a setting causes a slight gap between the outer peripheral surface of the plug blade and the inner peripheral surface of the blade receiving hole when the plug blade is inserted into the blade receiving hole. The following two problems were caused by this gap.

  First, dust accumulates in the gap and a short circuit occurs, which may cause a so-called tracking fire. Second, the gap caused the plug to become loose, causing the plug blade to easily come out of the receptacle hole of the outlet. In particular, in the OA device, if the power supply is cut off without following a predetermined procedure, the internal data of the device may be damaged or disappeared, and the situation in which the plug blade easily falls out has been a serious problem.

  In order to avoid the above problems, an insertion plug provided with a blade cap has been proposed as a tracking-resistant member that closes the gap. The blade cap is a member that fits in and closes the gap between the outer peripheral surface of the plug blade and the inner peripheral surface of the blade receiving hole when the plug blade is inserted into the blade receiving hole of the outlet. By providing this blade cap, it is possible to prevent dust and the like from accumulating in the gap and to prevent the occurrence of a tracking fire. In addition, since the blade cap fits into the gap, the plug blade can be securely fixed to the blade receiving hole of the outlet, and there is no fear of the plug being loose.

  As a conventional example of the above-described plug, there is one disclosed in Patent Document 1. In this conventional example, a sleeve-like blade cap is fitted into the root portion of a plug blade in a double-structured plug having a core made of a thermosetting resin. That is, as shown in FIG. 9, the plug 1 is provided with a plug body 2 made of an insulating material, and plug blades 3 </ b> A and 3 </ b> B inserted into the blade receiving holes of the outlet, Is attached. These plug blades 3A, 3B and the power cord 4 are connected by a connecting portion J. The plug body 2 incorporates a core 6 made of a thermosetting resin that holds the plug blades 3A and 3B in a predetermined position. More specifically, the front surface 60 of the core 6 is embedded so as to form a part of the abutting surface 20 of the plug body 2.

Further, in a state where the plug blades 3A and 3B are inserted into the blade receiving holes of the outlet, the core 6 is closed so as to block a small gap between the outer peripheral surface of the plug blades 3A and 3B and the inner peripheral surface of the blade receiving hole. A sleeve-like blade cap 5 made of an insulating material separate from the core 6 is inserted into each of the base portions of the plug blades 3A and 3B protruding from the core blade 6A. At this time, the rear end portion of the blade cap 5 is disposed in the core 6. A flange 50 is integrally formed at the rear end of the blade cap 5 so as to prevent the blade cap 5 from coming off from the core 6.
JP-A-10-308251

  However, the prior art has the following problems. That is, since the sleeve portion of the blade cap 5 is intended to close the gap between the blade receiving hole of the outlet and the plug blades 3A, 3B, the wall thickness must be reduced. If the wall thickness exceeds the gap, the plug blades 3A and 3B do not enter the blade receiving holes of the outlet, which is dangerous. That is, high processing accuracy is required for the sleeve portion of the blade cap 5. Moreover, in the blade cap 5 of the conventional example, a flange 50 for preventing displacement and falling off is integrally formed in such a thin sleeve portion. Therefore, the required processing accuracy has become extremely high, and manufacturing has been difficult. Further, since the blade cap 5 and the core 6 are separate parts, it is necessary to separately manage storage and the like.

  Furthermore, when assembling the above conventional example, the blade cap 5 is inserted from the tip of the plug blades 3A and 3B toward the root portion, but since the thickness of the blade cap 5 is thin, it is inserted into the plug blades 3A and 3B. The work will use nerves. Moreover, since the blade caps 5 are inserted into the plug blades 3A and 3B, the assembly workability is low. In the conventional example, the plug blades 3 </ b> A and 3 </ b> B are inserted into the core 6 with the blade cap 5 attached. When this operation is performed, the blade cap 5 may move, which is also a factor that reduces the assembly workability.

  Although it has already been described that the blade cap 5 is difficult to manufacture because of its thin wall thickness, it is necessary to ensure a certain thickness in order to increase productivity. That is, in order to ensure the thickness of the blade cap 5, it is conceivable to reduce the thickness of the blades of the plug blades 3A and 3B into which the blade cap 5 is inserted. However, in order to manufacture such plug blades with special specifications, new equipment is indispensable, resulting in an increase in cost.

  As described above, in the prior art, high processing accuracy is indispensable for the blade cap, and the assembly work is troublesome. For this reason, productivity has been low and improvement in economy has been desired. The present invention has been proposed in order to solve such a problem, and the object thereof is an insertion plug including a core made of a thermosetting resin and a blade cap corresponding to tracking resistance. The aim is to improve the productivity by improving the assembly workability, and thereby to provide a plug having excellent reliability and economy.

  In order to achieve the above-mentioned object, the invention of claim 1 is made of a thermosetting resin which is attached to a plug body made of an insulating material and has a pair of plug blades to be inserted into the blade receiving holes of the outlet. A blade cap having a sleeve portion is provided at the base portion of the plug blade protruding from the plug body, and the outer periphery of the blade cap when the plug blade is inserted into the blade receiving hole of the outlet In the insertion plug configured such that the surface is in contact with the inner peripheral surface of the blade receiving hole and the gap between the plug blade and the blade receiving hole is closed, the blade cap is formed directly and integrally with the core. It is characterized by that.

  In such an invention, since the blade cap is formed directly and integrally with the core by insert molding or the like, the blade cap becomes a part embedded in the core. Therefore, since the plug blade is inserted into the integrally formed core and blade cap, there is no fear that the position of the blade cap shifts or falls off when the plug blade is inserted. Further, by integrally forming the blade cap on the core, the protruding amount (height) of the blade cap from the plug body can be made constant at all times. Moreover, instead of inserting a blade cap into each of the pair of plug blades, the pair of plug blades can be inserted almost simultaneously toward the blade cap embedded in the core. Thereby, assembly work can be carried out efficiently. Furthermore, it is not necessary to provide a flange that requires high processing accuracy at the sleeve portion where the thickness of the blade cap is required to be thin. According to the present invention as described above, the assembly workability is improved, and the productivity can be improved. In addition, since it is not necessary to insert a blade cap into each of the pair of plug blades and to provide the blade cap with positioning of the plug blade, it is possible to manufacture the plug blade production equipment as it is without using new production equipment. Can be realized at low cost.

According to a second aspect of the present invention, in the plug according to the first aspect, the blade cap is made of a polyamide resin.
In this invention, since the blade cap is made of polyamide resin, its durability can be greatly increased compared to the case where the blade cap is made of the same thermosetting resin as the core, and cracks, chips, etc. Occurrence can be prevented.

According to a third aspect of the present invention, in the plug according to the second aspect, the gate portion for filling the polyamide resin, which serves as the blade cap, is formed at a central portion of the blade cap projecting surface of the core. It is a feature.
According to such an invention, the flow of the molding resin at the time of injection molding can be improved by providing the gate portion for filling the polyamide resin at the central portion of the blade cap protruding surface in the core. Therefore, it is possible to fill the molding resin evenly on the left and right, and to increase the productivity of the blade cap.

According to a fourth aspect of the present invention, in the insertion plug according to any one of the first to third aspects, a blade holding portion for holding the plug blade is provided at a rear end portion of the blade cap. It is said.
In the above invention, since the plug blade is held by the blade holding portion at the rear end portion of the blade cap after the plug blade is inserted into the core and the blade cap, it is not necessary to regulate the position of the blade cap with respect to the plug blade. As a result, the protrusion amount (height) of the blade cap from the abutting surface of the plug body can be made constant, and the blade cap can stably close the gap between the plug blade and the blade receiving hole.

According to a fifth aspect of the present invention, in the insertion plug according to any one of the first to fourth aspects, a tapered portion that guides the insertion of the plug blade is formed on an inner peripheral surface of the blade cap. It is said.
According to the fifth aspect of the present invention, the plug blade can be smoothly inserted along the taper portion of the inner peripheral surface of the blade cap even if the plug blade is slightly inserted into the sleeve portion of the blade cap in dimension. be able to. Thereby, it is possible to carry out the assembly work easily and reliably.

According to a sixth aspect of the present invention, in the insertion plug according to any one of the first to fifth aspects, a chamfered portion is provided on an outer periphery of a sleeve base portion of the blade cap.
In such a sixth aspect of the invention, by providing a chamfered portion on the outer periphery of the root portion of the sleeve portion in the blade cap, it becomes easy to fill the molding resin up to the tip portion of the blade cap, and the injection pressure at the time of injection molding is kept low. be able to. For this reason, damage to the core due to the injection pressure can be prevented. The chamfered portion increases the strength of the sleeve base. Therefore, it is possible to prevent the blade cap sleeve portion from being bent, deformed, or damaged until the plug blade is inserted into the blade cap.

According to a seventh aspect of the present invention, in the insertion plug according to any one of the first to sixth aspects, the root portion of the sleeve portion of the blade cap is configured to be thicker than the sleeve portion.
In the invention of the above-mentioned claim 7, by forming the sleeve portion base portion thicker than the sleeve portion in the blade cap, the flowability of the molding resin from the root portion to the sleeve portion is improved, and the wall thickness dimension It is possible to reliably fill the molding resin even in a thin part. Therefore, it is not necessary to use a special specification plug blade in which the thickness of the blade for securing the thickness of the sleeve portion is reduced, and an existing general specification plug blade can be used. As a result, there is no need for new equipment for making a special specification plug blade, and a reduction in manufacturing cost can be realized.

The invention according to claim 8 is the insertion plug according to any one of claims 1 to 7, characterized in that a thick corner portion of the root portion of the sleeve portion of the blade cap is formed in an R shape. .
In the invention of claim 8 above, when the blade corner portion of the blade cap sleeve portion is formed in an R shape, the injection pressure applied to the wall thickness corner portion during the injection molding of the blade cap can be reduced, and the sleeve The crack of the core near the corner of the root portion can be prevented.

  As described above, according to the plug of the present invention, in the plug including the thermosetting resin core and the tracking-capable blade cap, the blade cap is directly integrated with the core. By molding into a good shape, good assembly workability and high productivity can be secured, and excellent reliability and economy can be obtained.

  Hereinafter, an example of the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be specifically described with reference to FIGS. 1 is a horizontal sectional view of the present embodiment, FIG. 2 is a front view of a blade cap and a core in the present embodiment, FIG. 3 is a sectional view taken along line AA ′ of FIG. 2, and FIG. B 'sectional view, FIG. 5 is a sectional view taken along the line CC ′ of FIG. 2, FIG. 6 is a rear view of the main part of the blade cap and the core in the present embodiment, and FIG. 7 is a sleeve portion of the blade cap in the present embodiment. FIG. 8 is a front view of an outlet into which the present embodiment is inserted. In the present embodiment, the same members as those in the conventional example shown in FIG.

[Constitution]
The present embodiment is a double structure type insertion plug in which a core 9 made of a thermosetting resin is incorporated in the plug body 2, and the blade cap 8 having the sleeve portion 80 is the plug blade 3A, 3B. It is embedded in the base. The structural features of such an insertion plug 7 are as follows. That is, the blade cap 8 is directly and integrally formed in the core 9 by insert molding or the like. The sleeve portion 80 is formed as a pair of left and right, and protrudes from the front surface of the core 9 when the blade cap 8 is integrally formed with the core 9.

  The blade cap 8 is made of polyamide resin, and a blade holding portion 81 (shown in FIG. 5) for holding the plug blades 3A and 3B is provided at the rear end portion of the blade cap 8. The sleeve portion 80 of the blade cap 8 is formed with an opening 82 into which the plug blades 3A and 3B can be inserted. The thickness of the sleeve 80 is such that the plug blades 3A and 3B are inserted into the blade receiving holes 11 and 11B of the outlet 11, and the outer peripheral surfaces of the plug blades 3A and 3B and the inner peripheral surfaces of the blade receiving holes 11A and 11B. Are processed to approximately the same dimensions as the gap C (see FIG. 8). That is, when the plug blades 3A and 3B are inserted into the blade receiving holes 11A and 11B of the outlet 11, the outer peripheral surface of the sleeve portion 80 is in contact with the inner peripheral surfaces of the blade receiving holes 11A and 11B and the plug blades 3A and 3B The gap C between the holes 11A and 11B is configured to be closed. Further, a chamfered portion 83 is provided at the distal end portion of the sleeve portion 80. This is to ensure that the sleeve portion 80 is smoothly inserted into the gap C.

  Further, as shown in FIGS. 1, 3, and 7, a chamfered portion 84 is also provided on the outer periphery of the root portion of the sleeve portion 80 of the blade cap 8. Further, a tapered portion 85 for guiding insertion of the plug blades 3A and 3B is formed on the inner peripheral surface of the blade cap 8 (shown in FIGS. 3 and 7). As shown in FIG. 2, the blade cap 8 has a thick portion 87 having a thicker thickness than the sleeve portion 80 at the base portion of the sleeve portion 80. Further, an R-shaped portion 86 that draws a gentle curve is formed at the corner portion of the thick portion 87 at the root portion of the sleeve portion 80 of the blade cap 8.

  The core 9 is made of a thermosetting resin, is embedded in the plug body 2 in a state of being integrally molded with the blade cap 8 embedded therein, and its front surface forms part of the abutting surface 20 of the plug body 2. It is supposed to be. Further, blade insertion holes 91A and 91B are provided on the front surface of the core 9 in a positional relationship corresponding to the blade receiving holes 11A and 11B of the outlet 11 shown in FIG. 8 (shown in FIGS. 3 and 6). The blade insertion holes 91A and 91B are configured such that the sleeve portion 80 of the blade cap 8 protrudes therefrom. Furthermore, the core 9 is provided with a core holding portion 92 that presses the rear surface portion of the blade cap 8 from the rear (see FIGS. 1, 3 and 4). Further, a polyamide resin filling gate portion 93 which becomes the blade cap 8 is provided at the center of the protruding surface of the blade cap 8 in the core 9 (see FIGS. 1 to 4). The step portion 94 formed near the gate portion 93 serves to fix the blade cap 8 in the same manner as the core holding portion 92.

[Effect]
The operational effects of the present embodiment having the above-described configuration are as follows. That is, the blade cap 8 is directly and integrally molded with the core 9 by filling the polyamide resin from the gate portion 93 of the core 9. At this time, since the gate portion 93 is located at the center portion of the protruding surface of the blade cap 8 in the core 9, the polyamide resin can flow evenly in the left-right direction. That is, the polyamide resin can be uniformly distributed, and the blade cap 8 with high reliability can be manufactured.

  Further, the blade cap 8 is provided with a thick portion 87 at the base portion of the sleeve portion 80 so that the base portion is thicker than the sleeve portion 80. For this reason, at the time of injection molding, the polyamide resin smoothly flows from the base portion side to the tip portion, and even a portion having a small thickness is reliably filled. In such an embodiment, it is not necessary to prepare a plug blade with a thin blade for the purpose of securing the thickness of the sleeve portion 80. This eliminates the need for new equipment for making special specification plug blades, and allows the use of conventional equipment for producing general specification plug blades as they are. It is.

  As described above, in the present embodiment in which the blade cap 8 is integrally formed with the core 9, the blade cap 8 is a single part embedded in the core 9. In this component, since the core holding portion 92 and the stepped portion 94 fix the blade cap 8, the blade cap 8 in the core 9 is not likely to be displaced or fall off. Therefore, when the plug blades 3A and 3B are inserted into the blade cap 8 and the core 9, the plug blades 3A and 3B can be inserted by holding only the core 9, and excellent assembly workability can be exhibited. . In addition, since the tapered portion 85 is formed on the inner peripheral surface of the blade cap 8, even if the plug blades 3A and 3B are slightly inserted into the sleeve portion 80 of the blade cap 8, the plug blades 3A and 3A are formed along the tapered portion 85. 3B can be smoothly inserted, and plug blades 3A and 3B can be inserted easily and reliably.

  Further, after the plug blades 3A and 3B are inserted into the core 9 and the blade cap 8, the blade holding portion 81 of the blade cap 8 holds the plug blades 3A and 3B, so the position of the blade cap 8 with respect to the plug blades 3A and 3B. There is no need to regulate. As a result, the protruding amount (height) of the blade cap 8 from the abutting surface 20 of the plug body 2 becomes constant, and the blade cap 8 reliably closes the gap C between the plug blades 3A and 3B and the blade receiving holes 11A and 11B. Can do.

  Further, in the conventional example shown in FIG. 9, the blade cap 5 is inserted into each of the plug blades 3A, 3B, but in this embodiment, the blade cap 8 embedded in the core 9 and integrally molded is a pair of left and right. Since the sleeve portion 80 is provided, the plug blades 3A and 3B can be simultaneously inserted therein. Further, the blade cap 5 of the conventional example is provided with the flange 50 in order to prevent displacement and dropout. However, in this embodiment, the core 9 and the blade cap 8 are integrated, so that the flange is attached to the blade cap. There is no need to provide it. Therefore, manufacture of a member becomes easy and productivity can be improved. In the present embodiment, since the blade cap 8 is made of polyamide resin, the durability can be greatly improved as compared with the case where the blade cap 8 is made of the same thermosetting resin as the core 9.

  Further, since the chamfered portion 84 is provided on the outer periphery of the root portion of the sleeve portion 80 in the blade cap 8, the polyamide resin can be smoothly filled up to the tip portion of the blade cap 8, and the injection pressure at the time of injection molding can be reduced. it can. In addition, since the corner portion 86 of the thick portion 87 of the base portion of the sleeve portion 80 of the blade cap 8 is the R-shaped portion 86, the injection pressure to the corner portion that is weak in strength at the time of injection molding can be reduced. According to the present embodiment as described above, there is no fear that the core 9 is damaged by the pressure when the resin is injected, and it is safe. The chamfered portion 84 serves as a reinforcement for the root portion of the sleeve portion 80. Therefore, it is possible to prevent the sleeve portion 80 of the blade cap 8 from being bent, deformed, or damaged until the plug blades 3A and 3B are inserted into the blade cap 8.

  In addition, this invention is not limited to the said embodiment, The structure, material, etc. of each member can be changed suitably. For example, in the above embodiment, an example in which the present invention is applied to a two-pole plug having a pair of blades 3A and 3B has been shown, but the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to a connector having any number of poles. Moreover, the shape of each part can also be selected suitably, for example, as the R-shaped part of the corner | angular part in the sleeve part 80 base part of the blade cap 8, the whole root part is good also as an ellipse.

Horizontal sectional view of this embodiment Main part front view of the present embodiment A-A 'sectional view of FIG. B-B 'sectional view of FIG. C-C 'sectional view of FIG. Main part rear view of the present embodiment Enlarged horizontal sectional view of the sleeve portion of the blade cap in the present embodiment Front view of the outlet into which this embodiment is inserted Horizontal section of a conventional plug

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,7 ... Plug 2 ... Plug body 3A, 3B ... Plug blade 4 ... Power cord 5, 8 ... Blade cap 6, 9 ... Core 80 ... Sleeve part 81 ... Blade holding part 82 ... Opening part 83, 84 ... Chamfered portion 85 ... Tapered portion 86 ... R-shaped portion 87 ... Thickness portions 91A, 91B ... Blade insertion hole 92 ... Core holding portion 93 ... Filling gate portion 94 ... Step portion

Claims (8)

The plug body made of an insulating material is attached with a pair of plug blades to be inserted into the blade receiving holes of the outlet, and a core made of a thermosetting resin that holds these plug blades is incorporated, and the plug protrudes from the plug body A blade cap having a sleeve portion is provided at the base of the blade, and when the plug blade is inserted into the blade receiving hole of the outlet, the outer peripheral surface of the blade cap is in contact with the inner peripheral surface of the blade receiving hole. In an insertion plug configured to close a gap between a blade and a blade receiving hole,
The plug plug is characterized in that the blade cap is directly formed integrally with the core.   The plug according to claim 1, wherein the blade cap is made of a polyamide resin.   The insertion plug according to claim 2, wherein a gate portion for filling the polyamide resin serving as the blade cap is formed at a center portion of the blade cap projecting surface of the core.   The insertion plug according to any one of claims 1 to 3, wherein a blade holding portion that holds the plug blade is provided at a rear end portion of the blade cap.   The insertion plug according to any one of claims 1 to 4, wherein a tapered portion that guides insertion of the plug blade is formed on an inner peripheral surface of the blade cap.   The plug according to any one of claims 1 to 5, wherein a chamfered portion is provided on an outer periphery of a sleeve portion base portion of the blade cap.   The insertion plug according to any one of claims 1 to 6, wherein the sleeve base portion of the blade cap is configured to be thicker than the sleeve portion.   The insertion plug according to any one of claims 1 to 7, wherein a thick corner portion of the base portion of the sleeve portion of the blade cap is formed in an R shape.

Images