JP2019058022A - Inner core and normal temperature shrinkable tube - Google Patents

Abstract

To provide an inner core with which it is possible to prevent the inner core from falling off when being removed from a cylindrical elastic member and a normal temperature shrinkable tube equipped with the inner core.SOLUTION: An inner core inserted into an inside of a diameter-expandable cylindrical flexible member of substantially a cylindrical shape from an open end of the cylindrical flexible member and used for holding the expanded diameter of the open end of the cylindrical flexible member, comprises a substantially cylindrical inner core body having an outside diameter larger than an inside diameter of the open end of the cylindrical flexible member, and a grip part attached to one end in a center axis direction of the inner core body. The grip part includes a first continuous part and a second continuous part that are continuous to the one end in the center axis direction of the inner core body, a first belt-like part continuous to the first continuous part, a second belt-like part continuous to the second continuous part, a third belt-like part continuous between the vicinity to the first continuous part in the first belt-like part and the vicinity to the second continuous part in the second belt-like part, and an arced belt-like part continuous between the first belt-like part and the second belt-like part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cold-shrinkable tube that can be reduced in diameter at room temperature, and an inner core used therefor.

  An electric wire provided with a conductor such as a copper wire is usually used as a covered electric wire whose entire surface is covered and protected by an insulator such as rubber. However, when connecting the covered electric wires to extend the use by adding several such covered electric wires, the connecting portion constituted by the conductor is exposed to the outside. It is necessary to protect the coating with such as

  Conventionally, in order to cover and protect the connecting portions of the covered electric wires, a technique in which an operator manually wraps a tape made of an insulator, a rubber plate member, or the like around the connecting portions. However, depending on the skill level of the operator, the coating protection with tape or rubber varies. Further, in general, the covering protection work with a tape or the like of the connection portion is a live wire work performed at a high place in a state where a voltage is applied to the covered electric wire, and the worker uses a tool called a hot stick. Since it is performed with respect to the connection part located above the head, there is also a problem that workability is extremely poor. Therefore, a cold shrinkable tube has been proposed that can easily cover and protect the connecting portion.

  As a normal temperature shrinkable tube, for example, a cylindrical member made of a substantially cylindrical elastic material, a diameter expanding member inserted at both ends of the cylindrical member, and a diameter expanding member so as to cover the outer peripheral surface of the diameter expanding member The thing which has the sliding member attached to is proposed (refer patent document 1).

JP 2009-165214 A

  The diameter-expanding member in the normal temperature shrinkable tube described in Patent Document 1 is a pair of main body portions having a shape obtained by dividing a cylinder into two by a plane to which the long axis belongs, and a plan view extending from each of the pair of main body portions. And a U-shaped handle portion. When attaching this cold-shrinkable tube to the connection part between the covered wires, the handle part is placed in the axial direction of the tubular member above the operator's head with the hook part of a tool called a hot stick hooked on the handle part. Pulled along. Thereby, the diameter-expanding member is pulled out from the cylindrical member, the cylindrical member contracts, and the connection portion between the covered electric wires is covered and protected.

  However, due to the inertial force when the diameter-expanding member is pulled out from the cylindrical member, there is a problem that the diameter-expanding member pulled out from the cylindrical member violently swings at the hook-like portion of the hot stick and falls. is there. Since the installation work of the cold shrink tube is performed at a high place, it is a problem that the diameter-expanded member should be prevented from dropping.

  In view of such a problem, an object of the present invention is to provide an inner core that can be prevented from falling when pulled out from a cylindrical elastic body, and a cold-shrinkable tube including the inner core.

  In order to solve the above problems, the present invention is inserted into the inside of the cylindrical elastic body from the opening end of a substantially cylindrical cylindrical elastic body capable of expanding the diameter, and the opening end of the cylindrical elastic body is An inner core used for expanding the diameter of the cylindrical core, and a substantially cylindrical inner core body having an outer diameter larger than the inner diameter of the opening end of the cylindrical elastic body, and one end in the central axis direction of the inner core body A gripping portion attached to the first core, the gripping portion includes a first continuous portion and a second continuous portion that are continuous with one end portion in the central axis direction of the inner core body, and a first continuous portion that is continuous with the first continuous portion. A first belt-like portion, a second belt-like portion continuous with the second belt-like portion, a portion in the vicinity of the first belt-like portion in the first belt-like portion, and a portion in the vicinity of the second belt-like portion in the vicinity of the second continuous portion. Continuous between three strips and the first strip and the second strip Providing an inner core which comprises an arc strip portion that.

  In the inner core, orthogonal to the central axis direction between a first position near the first continuous portion on the first belt-like portion and a second position near the second continuous portion on the second belt-like portion. The distance in the direction in which the first belt is positioned is a third position on the first belt-shaped portion closer to the arc belt-shaped portion than the first position, and a distance on the second belt-shaped portion closer to the arc-shaped belt portion than the second position. It is preferable that the distance between the four positions is larger than the distance in the direction perpendicular to the central axis direction.

  In the inner core, a fifth position on the first belt-shaped portion closer to the arc belt-shaped portion than the third position, and a sixth position on the second belt-shaped portion closer to the arc belt-shaped portion than the fourth position. It is preferable that a distance in a direction perpendicular to the central axis direction between the positions is larger than the distance between the third position and the fourth position.

  In the inner core, it is preferable that each of the first continuous portion and the second continuous portion is substantially parallel to the central axis direction of the inner core body.

  In the inner core, the arc belt-shaped portion, a part of the first belt-shaped portion continuous with the arc belt-shaped portion, and a part of the second belt-shaped portion are located on an extension line of a central axis of the inner core main body. Preferably, each of the first continuous portion and the second continuous portion is continuous to a position on one end portion in the central axis direction of the inner core body facing each other in the radial direction of the inner core body. preferable.

In the inner core, an inner diameter of the inner core body is X, and a length in a direction parallel to the radial direction of the inner core body between the extension line of the central axis of the inner core body and the arc-shaped portion is S. , It is preferable that the inner diameter X and the length S have a relationship represented by the following formula.
0.2X ≦ S

  In the inner core, the inner core main body includes a first inner core portion and a second inner core portion whose cross-sectional shape in a direction orthogonal to the central axis direction is a substantially semicircular shape, and the first continuous portion. Is preferably continuous with one end portion of the first inner core portion, and the second continuous portion is continuous with one end portion of the second inner core portion.

  In addition, the present invention provides a substantially cylindrical tubular elastic body that can be expanded in diameter, and an open end portion of the tubular elastic body that is inserted into the tubular elastic body from an open end portion of the tubular elastic body. Characterized in that it comprises the inner core for expanding the diameter and a sliding member provided on the outer periphery of the inner core body for facilitating sliding when the inner core is pulled out from the cylindrical elastic body. Provide cold shrink tubing.

  The cold shrink tube is used for covering and protecting a connecting portion formed by connecting the ends of two coated wires, and the inner diameter of the inner core is the outer diameter of the covered wire. It is preferably 1.2 times or more.

  ADVANTAGE OF THE INVENTION According to this invention, a normal temperature shrinkable tube provided with the inner core which can prevent falling when pulled out from a cylindrical elastic body, and the said inner core can be provided.

FIG. 1 is a perspective view showing a schematic configuration of an inner core according to an embodiment of the present invention. FIG. 2 is a top view showing a schematic configuration of the inner core according to the embodiment of the present invention. FIG. 3 is a side view showing a schematic configuration of the inner core according to the embodiment of the present invention. FIG. 4 is a plan view showing a state in which the inner core according to the embodiment of the present invention is developed. FIG. 5 is a partially enlarged plan view showing a schematic configuration of one aspect of the grip portion in a state where the inner core according to the embodiment of the present invention is developed. FIG. 6 is a side view showing a schematic configuration of an inner core according to another embodiment of the present invention. FIG. 7 is a cross-sectional view illustrating a schematic configuration of a cold-shrinkable tube according to an embodiment of the present invention. FIG. 8 is a cross-sectional view schematically showing how to use the cold-shrinkable tube according to one embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing how to use the cold-shrinkable tube according to one embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing how to use the cold-shrinkable tube according to one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the inner core 10 according to the present embodiment includes a substantially cylindrical inner core body 11 and a grip portion 12 attached to one axial end of the inner core body 11. The inner core 10 is an open end portion of a substantially cylindrical cylindrical elastic body 2 that can be expanded in a normal temperature shrinkable tube 1 (see FIG. 7) used for covering and protecting the connecting portion 110 between the covered electric wires 100. It is inserted into the cylindrical elastic body 2 from 21 and 22 and used to expand and hold each of the open end portions 21 and 22 of the cylindrical elastic body 2.

  The inner core body 11 includes a first inner core portion 111 and a second inner core portion 112 that are combined so as to be split into two along the axial direction, and a first continuous portion 121 that is one end portion of the grip portion 12. Is attached to one axial end portion of the first inner core portion 111, and the second continuous portion 122, which is the other end portion of the grip portion 12, is attached to one axial end portion of the second inner core portion 112.

  The inner core 10 can be made of any material having a strength that can resist the elastic force (contraction force) of the cylindrical elastic body 2 (see FIG. 7), such as polyethylene, polypropylene, polyacetal resin, fluororesin, polystyrene, ABS. It is made of a resin material such as resin, polycarbonate, polyethylene terephthalate, nylon, acrylic, polyvinyl chloride, and the like, and can be produced, for example, by injection molding using the resin material.

The inner diameter R ₁₁ of the inner core body 11 is made larger than the outer diameter of the coated electric wire 100 (see FIG. 8-10), for example, more than 1.2 times the outer diameter of the coated electric wire 100 is preferably, 1.2 to It is particularly preferably 1.7 times. The inner diameter R ₁₁ is specifically about 7 to 48 mm, preferably about 10 to 18 mm. Since the inner diameter R ₁₁ of the inner core body 11 is larger than the outer diameter of the covered electric wire 100, the covered electric wire 100 can be easily passed through the cylindrical elastic body 2 through the inner core main body 11. The thickness of the inner core body 11 can be set to about 0.5 to 2.5 mm.

  The grip portion 12 includes a first continuous portion 121 and a second continuous portion 122 that are continuous with one axial end portion of the first inner core portion 111 and one axial end portion of the second inner core portion 112, and a first continuous portion. 121, a first belt-like portion 123 continuous to 121, a second belt-like portion 124 continuous to the second continuous portion 122, a vicinity of the first continuous portion 121 in the first belt-like portion 123, and a second continuous portion in the second belt-like portion 124. A third belt-like portion 125 that continues between the vicinity of the portion 122, and an arc-band-like portion 126 that continues between the first belt-like portion 123 and the second belt-like portion 124. With the gripping portion 12 having such a configuration, an annular portion 127 is formed by a part of the first belt-like portion 123 and the second belt-like portion 124, the third belt-like portion 125, and the arc belt-like portion 126. Therefore, even if the inner core 10 swings due to the inertial force when the hook-like portion or the like of the hot stick is hooked on the annular portion 127 (arc belt-like portion 126) and the inner core 10 is pulled out from the cylindrical elastic body 2, Can be suppressed.

  The third strip portion 125 is continuous between the first strip portion 123 and the second strip portion 124 in the vicinity of the first continuous portion 121 and the second continuous portion 122. If the hook-like portion of the hot stick is accidentally hooked on the third belt-like portion 125 and the inner core 10 is pulled out from the cylindrical elastic body 2, the third belt-like portion 125 may be damaged. If the 3rd strip | belt-shaped part 125 is damaged, the said annular part 127 will no longer be formed and it will become impossible to suppress the fall of the inner core 10. FIG. However, since the third strip 125 continues between the first strip 123 and the second strip 124 in the vicinity of the first continuous portion 121 and the second continuous portion 122, the third strip 125 and the inner Since the gap between the core body 11 and the core body 11 can be narrowed, it is possible to prevent the hook-like portion of the hot stick from being accidentally hooked on the third belt-like portion 125. In a top view of the inner core 10 (see FIG. 2), the length L between the one end portion of the inner core body 11 and the third belt-like portion 125 (the length along the axial direction of the inner core body 11) is 0. It can be set to about 10 mm. If the said length L is about 0-10 mm, it can suppress more effectively that the hook-shaped part of a hot stick is accidentally hooked on the 3rd strip | belt-shaped part 125. FIG.

  Further, in a plan view (see FIG. 4) in a state where the inner core 10 according to the present embodiment is unfolded (see FIG. 4), the first position P1 in the vicinity of the first continuous portion 121 on the first strip portion 123 and the second strip portion 124. The first distance D1 (distance in the direction orthogonal to the central axis direction of the inner core body 11) between the second continuous portion 122 and the second position P2 near the second continuous portion 122 is closer to the arc-shaped portion 126 side than the first position P1. The second distance D2 between the third position P3 on the first belt-like portion 123 and the fourth position P4 on the second belt-like portion 124 closer to the arc belt-like portion 126 than the second position P2 (the inner core body 11). Greater than the distance in the direction perpendicular to the central axis direction). Furthermore, a fifth position P5 on the first strip 123 on the arc strip 126 side of the third position P3 and a sixth position P6 on the second strip 124 on the arc strip 126 side of the fourth position P4. The third distance D3 between the first core and the second core is greater than the second distance D2. Thereby, the space | interval of the 1st strip | belt-shaped part 123 and the 2nd strip | belt-shaped part 124 can be narrowed compared with the magnitude | size of the cyclic | annular part 127, and the 3rd continuous between the 1st strip | belt-shaped part 123 and the 2nd strip | belt-shaped part 124 is possible. It can be visually suppressed that the hook-like portion of the hot stick is accidentally hooked on the belt-like portion 125.

  It is preferable that the angle in the continuous part of the 3rd strip | belt-shaped part 125 and each of the 1st strip | belt-shaped part 123 and the 2nd strip | belt-shaped part 124 is 60-150 degrees. When the angle is 60 to 150 °, even if the hook-like portion of the hot stick is accidentally hooked on the third strip portion 125 and the inner core 10 is pulled out, the third strip portion 125 is hardly damaged. Is played. From such a viewpoint, it is preferable that the third belt-like portion 125 has a shape curved in a convex shape toward the inner core body 11 side.

  In the present embodiment, the widths of the first continuous part 121, the second continuous part 122, the first belt-like part 123, the second belt-like part 124, the third belt-like part 125, and the arc belt-like part 126 constituting the gripping part 12 are Although not limited, for example, it may be set to about 3 to 10 mm.

  The grip part 12 (the first continuous part 121, the second continuous part 122, the first belt-like part 123, the second belt-like part 124, the third belt-like part 125, and the arc belt-like part 126) has a width direction (short side) in a cross-sectional view. Direction) having a thick portion located at both ends and a thin portion sandwiched between the thick portions. Since the cross-sectional shape of the grip part 12 is such a shape, the strength of the grip part 12 can be increased.

  The first continuous portion 121 and the second continuous portion 122 are preferably provided substantially parallel to the central axis direction of the inner core body 11. When the first continuous portion 121 and the second continuous portion 122 are inclined with respect to the central axis direction of the inner core body 11, the first continuous portion 121 and the second continuous portion 121 are removed when the inner core 10 is pulled out from the cylindrical elastic body 2. There is a possibility that the stress applied to the two continuous portions 122 becomes large, and the grip portion 12 is torn off from the inner core body 11.

  In the side view of the inner core 10 according to the present embodiment, the first belt-like portion 123 and the second belt-like portion 124 are inclined with respect to the central axis direction of the inner core body 11, and the first belt-like portion 123 and the second belt-like portion. The arc-shaped portion 126 that continues between 124 may be substantially parallel to the direction of the central axis of the inner core body 11. As described above, in the grip portion 12 in the present embodiment, the annular portion 127 is formed by the first belt-like portion 123 and a part of the second belt-like portion 124, the third belt-like portion 125, and the arc belt-like portion 126. . When the cold-shrinkable tube 1 is installed on the covered electric wire 100, the annular portion 127 is positioned on the extension line of the central axis of the inner core body 11 in order to pass the covered electric wire 100 along the central axis direction of the inner core main body 11. The covered electric wire 100 may be passed through the annular portion 127 by mistake. If the inner core 10 is pulled out from the cylindrical elastic body 2 in this state, the pulled inner core 10 cannot be removed from the covered electric wire 100. However, the first belt portion 123 and the second belt portion 124 are inclined with respect to the central axis direction of the inner core body 11, and the arc belt portion 126 is substantially parallel to the central axis direction of the inner core body 11. The annular portion 127 is not positioned on the extension line of the central axis of the inner core body 11. Therefore, it is possible to prevent erroneous insertion of the covered electric wire 100 passing along the central axis direction of the inner core body 11 into the annular portion 127.

When the inner core 10 having such a configuration is viewed from above, the inner diameter X of the inner core body 11 and the length S between the extension line of the central axis of the inner core body 11 and the arc-shaped portion 126 (the inner core body 11). (The length in the direction parallel to the radial direction) preferably has the relationship represented by the following formula (1), more preferably has the relationship represented by the following formula (2), and is represented by the following formula (3). It is particularly preferred to have a relationship.
0.2X ≦ S (1)
0.2X ≦ S ≦ 3X (2)
0.3X ≦ S ≦ 2X (3)

  When the length S is less than 0.2 times the inner diameter X (0.2X> S), it is difficult to insert the covered electric wire 100 into the inner core body 11, or the covered electric wire 100 is attached to the inner core body 11. There is a risk of accidental insertion into the closed space 127 during insertion. On the other hand, when the length S exceeds 3 times the inner diameter X (S> 3X), the size of the whole room temperature shrink tube 1 including the inner core 10 becomes large, and work when the room temperature shrink tube 1 is used. There is a problem that the sex gets worse.

  In the inner core 10 according to the present embodiment, the first continuous part 121, the second continuous part 122, the first belt-like part 123, the second belt-like part 124, the third belt-like part 125, and the arc belt-like that constitute the grip part 12. The portion 126 may be located on an extension line of the central axis of the inner core body 11 (see FIG. 6).

  Then, the normal temperature shrinkable tube using the inner core 10 which concerns on this embodiment is demonstrated. FIG. 7 is a cross-sectional view showing a schematic configuration of a cold shrink tube in the present embodiment.

  The room temperature shrinkable tube 1 in the present embodiment is inserted into the cylindrical elastic body 2 from the substantially cylindrical cylindrical elastic body 2 capable of expanding the diameter, and the opening end portions 21 and 22 of the cylindrical elastic body 2, and is cylindrical. Inner core 10 for maintaining the diameter of each of open end portions 21 and 22 of elastic body 2 and a sliding member for facilitating sliding when pulling out inner core 10 from cylindrical elastic body 2 (not shown) Are attached so as to cover the connecting portion 110 (see FIGS. 8 to 10) of the two covered electric wires 100.

The cylindrical elastic body 2 is made of an insulating material having elasticity (for example, a rubber material such as ethylene propylene rubber, silicone rubber, chloroprene rubber, butyl rubber, nitrile rubber, or fluorine rubber, or an elastomer). Cylindrical elastic body 2, to cover the connection portion 110 of the covered electric wire 100 has only to have a sufficient length L _2, for example, about 70～300Mm, preferably about 100 to 150 mm. Further, the inner diameter R ₂₃ of the axial central portion 23 of the cylindrical elastic body 2 is larger than the outer diameter of the covered electric wire 100, for example, about 7 to 44 mm, preferably about 9 to 16 mm. The inner diameter of 22 is equal to or smaller than the outer diameter of the covered electric wire 100, for example, about 4 to 34 mm, preferably 4 to 7 mm.

  An inner core 10 for forcibly expanding the diameter of the open ends 21 and 22 and maintaining the expanded state is inserted into the open ends 21 and 22 of the cylindrical elastic body 2. A sliding member for easily sliding the inner core 10 when the inner core 10 is pulled out from the cylindrical elastic body 2 is attached to the other axial end of the inner core body 11.

  The member for sliding should just have the structure which can slide the inner core 10 easily. The sliding member is continuous with a predetermined position on a long side of one of the substantially rectangular winding portions wound around the outer peripheral surface of the inner core main body 11 along the circumferential direction of the inner core main body 11, for example. In addition, the inner core body 11 may include a folded portion that is folded back so as to press the wound portion wound around the outer peripheral surface of the inner core body 11 from the outside. In the sliding member having such a configuration, the winding portion that is wound around the outer peripheral surface of the inner core body 11 and is pressed from the outside by the folded portion, together with the inner core body 11, the open end portion 21 of the cylindrical elastic body 2. , 22 are inserted. The sliding member only needs to have at least one folded portion, and preferably has 2 to 4 folded portions.

  As the sliding member, for example, a resin film made of a resin material such as polyethylene terephthalate (PET), polypropylene, polyethylene, or polystyrene is used. The thickness of the sliding member is not particularly limited, and is, for example, 10 to 100 μm, preferably 20 to 60 μm. A release layer composed of a silicone resin or the like may be provided on at least one surface of the resin film constituting the sliding member.

  The cold-shrinkable tube 1 having the above-described configuration can be used as a joint that covers and protects the connecting portion 110 between the covered electric wires 100. 8-10 is sectional drawing which shows roughly the usage method of the normal temperature shrinkable tube 1 in this embodiment.

  First, two covered electric wires 100 to be connected are prepared. The covered electric wire 100 has a configuration in which the entire surface of a conductor such as a copper wire is covered and protected with an insulator such as rubber. Then, the one covered electric wire 100 is completely passed through the one inner core 10 of the room temperature shrinkable tube 1 and is abutted with the other covered electric wire 100 to constitute the connecting portion 110 (see FIG. 8). The connection part 110 is not covered with an insulator and has a configuration in which a conductor is exposed. The annular portion 127 formed by the grip portion 12 of the inner core 10 according to the present embodiment is positioned so as to deviate from the extension line of the central axis of the inner core body 11, so When passing through, the covered electric wire 100 is not passed through the annular portion 127.

  Next, the cold-shrinkable tube 1 is slid to place the connecting portion 110 at the axially central portion 23 of the cylindrical elastic body 2, and the connecting portion 110 is completely covered with the cold-shrinkable tube 1 (see FIG. 9). . Thereafter, the hook-shaped portion of the hot stick is hooked on the annular portion 127 of the grip portion 12 of the inner core 10 to pull the inner core 10 toward the outside of the cylindrical elastic body 2, and the inner core 10 is cylindrical with the sliding member. Pull out from the elastic body 2 (see FIG. 10). The pulled inner core 10 vibrates violently due to the inertial force when the inner core 10 is pulled out, but the third band 125 continues between the first band 123 and the second band 124 to form an annular shape. Since the portion 127 is formed, the inner core 10 can be prevented from dropping from the hook-like portion of the hot stick.

  Further, when the inner core 10 is pulled, the sliding member (winding portion) wound around the outer peripheral surface of the inner core body 11 slides while being unscrewed, so that the inner core 10 is easily pulled out with a weak force. be able to. When the inner core 10 is pulled out, the open end portions 21 and 22 of the cylindrical elastic body 2 that has been forcibly expanded in diameter by the inner core 10 contract, and the covered electric wire 100 is fixed. At this time, the winding portion wound around the outer peripheral surface of the inner core body 11 slides so as to be unscrewed when the inner core 10 is pulled out. Therefore, when the inner core 10 is pulled out, the sliding member is hardly sandwiched between the cylindrical elastic body 2 and the covered electric wire 100, and even if it is sandwiched, the sandwiched sliding member is weak together with the inner core 10. It can be easily pulled out with force. Thus, the connection part 110 in the cylindrical elastic body 2 is shielded and protected from the outside world.

  As described above, in the cold-shrinkable tube 1 according to the present embodiment, the grip portion 12 of the inner core 10 includes the first belt-like portion 123 and a part of the second belt-like portion 124, the third belt-like portion 125, and the arc-band shape. By having the annular portion 127 formed by the portion 126, the inner core 10 is prevented from dropping after being pulled out. In addition, the annular portion 127 is positioned so as to be displaced from the extension line of the central axis of the inner core body 11, whereby erroneous insertion of the covered electric wire 100 into the annular portion 127 can be prevented. Further, since the sliding member (winding portion) attached to the outer peripheral surface of the inner core body 11 slides so as to be unwound when the inner core 10 is pulled out, the inner core 10 can be easily removed from the cylindrical elastic body 2. Can be pulled out. Further, the sliding member is sandwiched between the cylindrical elastic body 2 and the covered electric wire 100 by sliding so that the winding portion wound around the outer peripheral surface of the inner core body 11 can be spirally unwound. Can be suppressed.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  In the above embodiment, the substantially rectangular winding part wound around the outer peripheral surface of the inner core main body 11 along the circumferential direction of the inner core main body 11, and the winding part wound around the outer peripheral surface of the inner core main body 11 outside The sliding member having the folded portion that is folded so as to be pressed from the above has been described as an example, but is not limited to such a mode.

  For example, the sliding member may be constituted by a plurality of strip-like portions that are continuous with the other end portion of the inner core body 11 and are folded back so as to partially cover the outer periphery of the inner core body 11. Such a strip-shaped portion may be made of the same material as the inner core body 11 and may be formed integrally with the inner core body 11, or a separately prepared strip plate may be used as the other end of the inner core body 11. It may be fixed to the part. Moreover, the strip-shaped part may be comprised with the resin film which consists of resin materials, such as a polyethylene terephthalate (PET), a polypropylene, polyethylene, a polystyrene.

  The sliding member has an annular shape in which the outer peripheral surface and the inner peripheral surface of a part of the inner core body 11 in the circumferential direction are enclosed in the axial direction of the inner core main body 11, and the outer peripheral surface and the inner peripheral surface are closed. May be constituted by a plurality of annular films capable of continuously circulating in the axial direction of the inner core body 11. According to such an aspect, when the inner core 10 is pulled, the sliding member (annular film) slides so as to circulate along the axial direction of the inner core body 11, so that the inner core 10 is weak. It can be easily pulled out with force.

  Furthermore, the sliding member is not provided, and a lubricant (such as grease) that improves slippage between the inner core body 11 and the cylindrical elastic body 2 may be applied. Thereby, the inner core 10 can be pulled out easily.

DESCRIPTION OF SYMBOLS 1 ... Normal temperature shrinkable tube 2 ... Cylindrical elastic body 21,22 ... Opening end part 10 ... Inner core 11 ... Inner core main body 111 ... 1st inner core part 112 ... 2nd inner core part 12 ... Grip part

Claims (10)

An inner core that is inserted into the inside of the cylindrical elastic body from the opening end of a substantially cylindrical cylindrical elastic body capable of expanding the diameter and is used for maintaining the diameter of the opening end of the cylindrical elastic body. And
A substantially cylindrical inner core body having an outer diameter larger than the inner diameter of the opening end of the cylindrical elastic body;
A grip portion attached to one end of the inner core body in the central axis direction,
The gripping portion is continuous with the first continuous portion and the second continuous portion that are continuous with one end portion in the central axis direction of the inner core body, the first strip-shaped portion that is continuous with the first continuous portion, and the second continuous portion. The second belt-like portion, the third belt-like portion that continues between the vicinity of the first continuous portion in the first belt-like portion and the vicinity of the second continuous portion in the second belt-like portion, the first belt-like portion, and the An inner core comprising an arc belt-like portion continuous between the second belt-like portions.   The distance in the direction perpendicular to the central axis direction between the first position in the vicinity of the first continuous portion on the first strip and the second position in the vicinity of the second continuous portion in the second strip is , Between the third position on the first belt-like portion on the arc belt-like portion side of the first position and the fourth position on the second belt-like portion on the arc belt-like portion side of the second position. The inner core according to claim 1, wherein the inner core is larger than a distance in a direction orthogonal to the central axis direction.   Between the 5th position on the 1st belt-like part on the arc belt-like part side from the 3rd position, and the 6th position on the 2nd belt-like part on the arc belt-like part side rather than the 4th position. The inner core according to claim 2, wherein a distance in a direction orthogonal to the central axis direction is larger than the distance between the third position and the fourth position.   4. The inner core according to claim 1, wherein each of the first continuous portion and the second continuous portion is substantially parallel to the central axis direction of the inner core body.   The arc belt-like portion, a part of the first belt-like portion continuous with the arc belt-like portion, and a part of the second belt-like portion are not located on an extension line of the central axis of the inner core body. The inner core according to any one of claims 1 to 4. When the inner diameter of the inner core main body is X, and the length in the direction parallel to the radial direction of the inner core main body between the extension line of the central axis of the inner core main body and the arc belt-shaped portion is S, The inner core according to claim 5, wherein the inner diameter X and the length S have a relationship represented by the following formula.
0.2X ≦ S   The said 1st continuous part and the said 2nd continuous part are respectively connected to the position on the central-axis direction one end part of the said inner core main body which mutually opposes in the radial direction of the said inner core main body. The inner core in any one of -5. The inner core body has a first inner core portion and a second inner core portion whose cross-sectional shape in a direction orthogonal to the central axis direction is a substantially semicircular shape,
The first continuous portion is continuous with one end portion of the first inner core portion, and the second continuous portion is continuous with one end portion of the second inner core portion. The inner core according to any one of the above. An approximately cylindrical cylindrical elastic body capable of expanding the diameter;
The inner core according to any one of claims 1 to 7, which is inserted into the inside of the cylindrical elastic body from the opening end portion of the cylindrical elastic body, and holds the diameter of the opening end portion of the cylindrical elastic body,
A room temperature shrinkable tube, comprising: a sliding member provided on an outer periphery of the inner core body for facilitating sliding when the inner core is pulled out from the cylindrical elastic body. The normal temperature shrinkable tube is used for covering and protecting a connecting portion formed by connecting respective end portions of two covered electric wires,
The normal temperature shrinkable tube according to claim 8, wherein an inner diameter of the inner core is 1.2 times or more an outer diameter of the covered electric wire.

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