JP2001023720A - Power source cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cord with high performance and no dimensional error by insert-molding a part from a base of a plug blade to a tip of a cord in a specified separating position in a core of a thermoplastic elastomer and covering the core with suitable synthetic resin to form a shell and to form a plug part. SOLUTION: A plug blade 3 to which a cord 2 is connected is held between an upper mold 7 and a lower mold 8 in a specified separating arranging state, and in this state, synthetic resin is injected. As the synthetic resin, thermoplastic elastomer with high electric insulation and higher molding capability than thermosetting resin is used. A core 5 is set so as to cover from a base 3a of the plug blade 3 to an armor part 2b at the tip of the cord 2. Two covering parts 5b for covering the base 3a of the plug blade 3, a conductive wire 2a of the cord 2, and the armor part 2b at the tip of the cord 2 are projected to the back of an almost rectangular plate-shaped front part 5a. The rear end sides of two covering parts 5b are bent facing the focusing direction and a flange- shaped projection streak 5c is formed at the edge of the front part 5a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power cord having a plug at one end of the cord.

[0002]

2. Description of the Related Art To a power cord as described above, a plug blade is connected to a plurality of conductors protruding from the end of the cord, and the base side of the plug blade and the tip side of the cord are covered with vinyl chloride to form a plug. Some are forming parts.

When the plug portion is formed of one kind of vinyl chloride, it has advantages such as good moldability and low cost. However, if the plug blade generates heat due to overcurrent, the plug portion is overheated and tracking is likely to occur. In such a case, the vinyl chloride is carbonized and the insulation is impaired, which may cause a fire.

In addition, since the plug portion is formed at a time, sink is liable to occur in a thick portion, and there is a problem that the interval between the blades is disturbed.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a high performance, high dimensional performance by manufacturing using a thermoplastic elastomer which has good electrical insulation, high safety, and is easy to mold. The main task is to provide a power cord that does not have the above-mentioned irregularities.

A means for this purpose is a power cord in which plugs are formed by connecting plug blades to a plurality of conductors at the end of the cord, and covering the base side of these plug blades and the tip end of the cord with a synthetic resin to form a plug portion. Then, from the base of the blade to the tip of the cord in a predetermined spaced arrangement, insert molding is performed on a thermoplastic elastomer core, and an appropriate synthetic resin is coated from above the core to form an outer shell. And a power cord having a plug portion.

The core may be formed of an olefin or styrene thermoplastic elastomer.

The core may be formed at least on the front side of the plug portion so that the front surface of the core is exposed on the front surface of the plug portion.

Further, it is preferable to form a retaining structure between the core and the outer skin, which prevents the two from being separated by integrally forming the outer skin.

[0010]

According to the above structure, the plug portion made of synthetic resin is formed integrally with the core and the blade by insert molding using a thermoplastic elastomer, and from the base of the blade to the tip of the cord. And then forming the outer skin integrally. That is, since the conductive wire portion from the heating blade is held by the thermoplastic elastomer having high electrical insulation, it is possible to prevent occurrence of inconveniences such as tracking and the like, which can lead to danger, and to enhance safety. In addition, since the blade is held by the core, if the shape of the core is set appropriately so as not to cause sink marks, there is no inconvenience that the distance between the blades is unexpectedly changed, and a reliable power cord Can be obtained with certainty.

Further, since the core has a structure covered with the outer skin and is molded in at least two steps, the thickness of only a part of the core is increased, and the disadvantage that sink occurs after molding and the interval between the plug blades is deviated is prevented. it can. In addition, since the thickness is small, the cooling time in the mold for forming the core and the outer skin is short, so that the molding cycle time is short and economical.

Further, the thermoplastic elastomer has good moldability and good dimensional stability. Further, if the outer skin is formed of, for example, a thermoplastic elastomer, PVC can be removed. For this reason, even if the power cord which is difficult to recycle is incinerated, dioxin is not generated, and environmental problems can be solved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view of a power cord 1. The power cord 1 has a shape in which plug blades 3, 3 connected to the tip of a cord 2 are protruded from a plug part 4.
It is formed by two moldings. In this embodiment, a power cord 1 having two blades 3 and 3 will be described. However, the same applies to a power cord having a three-phase AC power supply.

The cord 2 is formed such that the outer periphery of the conducting wire 2a is formed of a rubber material such as chloroprene rubber, EP rubber, or chlorosulfonated polyethylene rubber, or an exterior material 2b such as an appropriate vinyl material.
It is a structure covered with.

The leading end of the cord 2 is divided into two parts by exposing the conducting wire 2a, and the conducting wire 2a is connected to the base 3a of the blade 3 by caulking or the like and integrated.

As shown in FIGS. 2 and 3, the blades 3 and 3 are insert-molded on the core 5 at a predetermined distance. Then, the outer shell 6 is formed using the integrated core 5 and the blade 3 as inserts to form the plug portion 4 so as to be in the state shown in FIG.

Specifically, in order to obtain the blade 3 and the core 5 in the state shown in FIG. 4, the cord 2 is placed between the upper die 7 and the lower die 8 as shown in FIG. Is held in a predetermined spaced state, and the synthetic resin is injected in this state.
As the synthetic resin, a thermoplastic elastomer which has good electric insulation properties and is much easier to mold than a thermosetting resin is used. Preferably, olefin-based or styrene-based thermoplastic elastomers are preferred due to their properties.

The shape of the core 5 is a shape located at least in the thick portion on the front side of the plug portion 4.
In this embodiment, the front surface of the core 5 is set to be exposed on the front surface of the plug portion 4. Although it is not necessary to expose the front surface of the core 5, it is better to expose the core 5, even if a synthetic resin that is not high in electrical insulation is used for the material of the outer cover 6, so that high security can be obtained. Good.

The core 5 is set so as to cover from the base 3a of the blade 3 to the tip of the cord 2.

That is, as shown in FIGS. 3 and 4, the base 3a of the blade 3 is provided on the back surface of the substantially rectangular plate-shaped front portion 5a.
And a wire 2a of the cord 2 connected to this portion, and two covering portions 5b projecting up to the exterior portion 2b at the end of the cord 2 are provided in a protruding manner. The two covering portions 5b are bent at their rear ends in the direction of convergence, and have a flange-shaped ridge 5c formed at the edge of the front surface portion 5a. The size of the front portion 5a is longer than the width of the blade 3 in the vertical direction, and longer than the interval between the blades 3 in the horizontal direction. In other words, the front surface portion 5a can surround and hold the blades 3 in the separated state. The size is set.

The thickness and width of the covering portion 5b are appropriately set so that the thickness of the outer cover 6 to be formed later can be made thin and substantially uniform.

Subsequently, in order to form the outer skin 6 as shown in FIG. 3, the plug blade 3 and the core 5 integrated by insert molding are separated into another predetermined shape as shown in FIG. The synthetic resin is injected between the upper mold 9 and the lower mold 10 having cavities. By this molding, the plug portion 4 is completed. As the synthetic resin, vinyl chloride or the like generally used for a plug is used. It is preferable to use the same thermoplastic elastomer as the core, and it is also possible to use a vinyl-based resin such as an olefin vinyl alcohol copolymer which does not generate dioxin even when incinerated as in the case of the thermoplastic elastomer.

By the second molding, the synthetic resin injected is formed into a ridge 5c on the front surface 5a of the core and the two covering portions 5c.
b and 5b to be integrated. For this reason, core 5
And the outer skin 6 can be reliably prevented from being separated. That is, the ridge 5c and the two covering portions 5b, 5b inclined in the convergence direction.
Has a retaining structure. In addition to the above shapes, for example, the outer peripheral portions of the coating portions 5b, 5b may be formed jagged. In short, it is sufficient that the synthetic resin forming the outer skin 6 has a shape that can bite the core.

As shown in FIG. 7, the core 5 may be provided with a root covering portion 5d for thinly covering the roots of the blades 3, 3 projecting from the plug portion 4 by a length of about several millimeters. . When formed in this manner, it is possible to prevent dust and the like from directly adhering to the root of the blade 3 while being inserted into the outlet. For this reason, the effect of preventing tracking is enhanced, and the safety and reliability can be further improved.

Further, as shown in FIG. 7, the rear ends of the two covering portions 5b, 5b of the core 5 may be connected to the left and right by the connecting portion 5e. A hole penetrating vertically is formed between the entire surface 5a and the connecting portion 5e, and becomes a part of a more complete retaining structure. The thickness of the outer skin 6 at a position corresponding to the connecting portion 5e is reduced, and Contribute to the prevention of outbreaks.

In the power cord 1 configured as described above,
The plug part 4 is formed by integrating the blade 3 with the thermoplastic elastomer core 5 by insert molding, and then integrally forming the outer skin 6 in the same manner. Moreover, the covering portions 5b, 5b of the core 5 are connected to the cord 2 from the base 3a of the blade 3 which generates heat.
Up to the tip.

That is, since the heat-generating portion is held by the thermoplastic elastomer having a high electrical insulation property, it is possible to prevent occurrence of inconveniences such as tracking, which may cause danger, and to enhance safety. In addition, since the blade 3 is held by the core 5, by appropriately setting the shape of the core 5 so as not to cause sink marks, there is no inconvenience that the interval between the blades 3 is unexpectedly changed, and the reliability is improved. Power cord 1 with high reliability can be obtained reliably.

The core 5 has a structure covered with the outer skin 6 and is formed in at least two steps.
Is formed with a covering portion 5e extending rearward, so that it is possible to prevent the disadvantage that the thickness of only a part is increased and sink occurs after molding and the interval between the blades 3 is deviated. Moreover, since the wall thickness is small, the dies 7, 8, 9, 10 in each molding process are required.
Since the cooling time is short, the molding cycle time is short and economical.

Further, the thermoplastic elastomer has good moldability and good dimensional stability. Further, the outer skin 6 is also formed of a thermoplastic elastomer, and the outer material 2b of the cord 2 is formed as described above.
Is made of a rubber material or a vinyl material, complete PVC removal can be achieved. For this reason, even if the power cord 1 that is difficult to recycle is incinerated, no dioxin is generated, and environmental problems can be solved.

The formation of the plug portion 4 may be performed three times instead of two times.

[Brief description of the drawings]

FIG. 1 is a perspective view of a power cord.

FIG. 2 is a perspective view showing a main part of a power cord.

FIG. 3 is a cross-sectional view of a power cord.

FIG. 4 is a side view of a blade, a core, and a cord.

FIG. 5 is an explanatory view of a core forming step.

FIG. 6 is an explanatory diagram of a skin forming step.

FIG. 7 is a perspective view of a main part of a power cord according to another example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Power cord 2 ... Cord 2a ... Conductor wire 3 ... Plug blade 3a ... Base part 4 ... Plug part 5 ... Core 5b ... Coating part 5c ... Projection 5e ... Connection part 6 ... Outer shell

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 5E063 JB01 JB05 JB06 JB08 XA02 XA04 XA20 5E087 EE10 FF02 FF13 GG02 GG34 JJ01 JJ04 JJ09 KK04 LL22 QQ03 RR01 RR06 RR18 RR25 RR47 RR49

Claims (4)

[Claims] 1. A power cord comprising a plug connected to a plurality of conductors at the end of a cord, and a plug formed by coating a base portion of the plug and a tip of the cord with a synthetic resin. At a predetermined distance from the base of the blade to the tip of the cord, insert molding is performed on a thermoplastic elastomer core, and a suitable synthetic resin is coated from above the core to form an outer cover, and a plug is formed. Power cord with formed part. 2. The power cord according to claim 1, wherein said core is formed of an olefin-based or styrene-based thermoplastic elastomer. 3. The power cord according to claim 1, wherein the core is located at least on the front side of the plug portion so that the front surface of the core is exposed on the front surface of the plug portion. 4. The retaining structure according to claim 1, wherein a stopper structure is formed between the core and the outer skin to prevent the two from being separated by integrally forming the outer skin. Power cord.