JP4190860B2 - Cold shrink tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a normal temperature shrinkable tube used for protecting a connection part such as an electric cable.
[0002]
[Prior art]
Conventionally, a cold shrinkable tube with an inner core as shown in FIG. 3 has been known for the purpose of protecting connection portions such as power cables and communication cables.
This is one in which an inner core 2 is inserted into a cold shrink tube 1 made of natural rubber, ethylene propylene rubber (EP rubber) or the like for the purpose of expanding the cold shrink tube 1 in diameter. In FIG. 3 , the inner core 2 is spirally wound into a tubular shape, but there is also an integral tubular shape from the beginning.
In Coldshrink 1 of the inner core containing, for example, when protecting the connection portion of the power cable, allowed to pass through the cold shrink tube 1 of the inner core 2 containing illustrated previously in FIG. 3 on one of the power cable to be connected When the connection between the power cables is completed, the room temperature shrinkable tube 1 containing the inner core 2 is moved onto the connecting portion, and when the inner core 2 is pulled out on the spot, the room temperature shrinkable tube 1 is shrunk on the spot and connected. Cover the part.
[0003]
Coldshrink 1 made in this manner is produced by the method shown in normal 4. That is, the above-described material made of natural rubber, ethylene propylene rubber, or the like is injected into a gap in the main mold 3 made up of two semicircular molds 3A, 3B and a core mold 3C and molded.
[0004]
[Problems to be solved by the invention]
However, in the cold shrink tube 1 manufactured in this way, material leaks at the joints of the molds 3A and 3B in FIG. 4 , and the positions 1A and 1B of the cold shrink tube 1, that is, the joints of the molds 3A and 3B. There was a case where burr was formed at the position corresponding to. When burrs are generated in this way, the burrs are scraped off with a file, a knife, or the like. At this time, the burrs are excessively cut, and the minimum wall thickness originally required for the cold shrink tube 1 may be broken.
[0005]
Therefore, the present invention has been made in view of the above problems, and its purpose is to generate a burr at the time of molding, and even if it is removed, the normal temperature shrinkage that does not easily break the minimum wall thickness that is originally required for a cold shrink tube. To provide a tube.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the cold-shrinkable tube according to claim 1 of the present invention, when taken out from the molding die, has a circular inner periphery and a semicircular shape except for a portion corresponding to the vicinity of the die alignment position. the shape, alignment consist semicircular in a portion corresponding to the vicinity of the elliptical shape protruding to the outside, the thickness of the portion corresponding to the mold alignment during molding becomes thicker than other portions It is characterized by that.
In this way, if the thickness of the portion corresponding to the die joint position of the normal temperature shrinkable tube is previously increased from the time of injection molding, even if burrs occur in this portion, the thickness of this portion is originally Is thicker than other parts, so even if a burr is shaved with a file or a knife, it is unlikely that too much shaving will occur below the minimum thickness required for a cold shrink tube.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
1 to 2 show an embodiment of the cold shrinkable tube of the present invention.
As shown in FIG. 1, when the cold-shrinkable tube 1 of the present invention is taken out from the molding die, thick portions 10 and 11 are provided at portions corresponding to the joint positions of the die at the time of molding. Reference numeral 2 denotes an inner core inserted inside the cold shrink tube 1 to expand the diameter of the cold shrink tube 1 so that the cold shrink tube 1 can be put on the connecting portions of various cables. It is formed by spiral winding.
The inner core 2 of this type, not string-like as shown in FIG. 3, some are simply cylindrical. Some are inserted in the cold shrink tube 1 in advance, and others are inserted into the cold shrink tube 1 in order to expand the cold shrink tube 1 on the spot when it is put on a connecting portion or the like.
[0008]
By the way, when manufacturing the normal temperature shrinkable tube 1 shown in FIG. 1, as shown in FIG. 2, in the molds 3A and 3B obtained by dividing the main mold 3 of the molding machine in advance, the inner surfaces in the vicinity of the joints 1A and 1B are formed. From the semicircular shape to an ellipse protruding outward, the other portions are made semicircular. If it does in this way, the thickness of the part corresponding to the joint position of metal mold | die 3A, 3B of the shape | molded normal temperature shrinkable tube 1 can be made thicker than another part. In addition, the code | symbol 3C is a core metal mold | die, and this uses the same circular thing as the past.
In this way, if the thickness of the part corresponding to the mold alignment position during molding is thicker than other parts, even if burrs occur at the position corresponding to the mold joint part, When scraping off with a knife or the like, there is less risk of cutting too much and breaking the minimum thickness required for the cold-shrinkable tube 1.
[0009]
In addition, as a suitable material of the normal temperature shrinkable tube 1 described above, for example, a rubber material exhibiting a permanent elongation of 30% or less, specifically, natural rubber, EP rubber, chloroprene rubber, butyl rubber, silicone rubber, etc. There is.
[0010]
【The invention's effect】
As described above, according to the cold-shrinkable tube according to claim 1 of the present invention, the thickness of the portion corresponding to the mold alignment position where burrs are likely to occur during molding is thicker than other portions. Even if burrs are generated at a position corresponding to the joint portion of the mold, when the burrs are scraped off with a knife or the like, the risk of breaking the minimum thickness required for the cold shrink tube 1 is reduced. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a cold shrinkable tube of the present invention.
2A and 2B are a side view and a front view showing a method for manufacturing the cold-shrinkable tube of the present invention shown in FIG .
3 is a side view and a front view of the cold shrink tube of a conventional inner core containing.
4 is a side view and a front view illustrating a conventional method for manufacturing a cold shrink tube.
[Explanation of symbols]
1 Cold shrink tube 2 Inner core 3 Mold

Claims (1)

When removed from the molding die, the inner circumference is circular, and the outer circumference is semicircular except for the part corresponding to the vicinity of the alignment position of the mold, and the part corresponding to the vicinity of the alignment position protrudes from the semicircular shape to the outside. Coldshrink that they become elliptical shape, the thickness of the portion corresponding to the mold alignment during molding, characterized in that it is thicker than other parts.

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