JP2010094011A - Diameter-enlarging member comprising core string, and cold shrinkable tube unit using diameter-enlarging member - Google Patents

Abstract

[PROBLEMS] To provide a core string that can maintain the expanded state of a cold-shrinkable tube when it is transported or constructed on-site without forming welding when forming an enlarged diameter holding member with a core string. An expanded diameter holding member and an expanded diameter holding method for a cold shrinkable tube using the expanded diameter holding member are provided.
A diameter-enlargement holding member 1 comprising a core cord 10 is fitted with a first convex portion 23 of a portion 12 of the core cord 10 and a second concave portion 26 of a portion 11 of the core cord 10 disposed adjacently. At the same time, the first concave portion 25 of the portion 12 of the core cord 10 and the second convex portion 24 of the portion 11 of the core cord 10 arranged adjacent to each other are fitted together.
[Selection] Figure 2

Description

  The present invention provides a diameter expansion holding member that holds a room temperature shrinkable tube in an expanded state, in particular, an expansion suitable for expanding the diameter of a thick room temperature shrinkable insulating cylinder used for insulation treatment of a high-voltage power cable. The present invention relates to a diameter holding member and a cold-shrinkable tube unit using the diameter-enlarged holding member.

  When connecting a power cable, the conductor of one power cable and the conductor of the other power cable are electrically connected by a connection sleeve, and an insulating rubber cold-shrinkable tube, so-called cold-shrinkable insulation, is provided on the outer periphery of the connecting portion. Insulating treatment is performed by mounting a cylinder.

  The cold-shrinkable tube before being attached to the power cable is held in an expanded state in which the diameter is expanded by a cylindrical expanded diameter holding member in which a core string is wound in a spiral shape. When the wound core string is released and the expanded diameter holding member is removed from the cold-shrinkable tube, the cold-shrinkable tube shrinks and adheres to the outer peripheral surface of the power cable.

  An example of this type of expanded diameter holding member is disclosed in Patent Document 1. The diameter-enlargement holding member described in Patent Document 1 is made of a resin core string having an uneven fitting portion.

JP 2006-187106 A

The core string is usually wound into a cylindrical shape by a winding molding device, and at the same time, the fitting portions are welded at a constant interval by an ultrasonic welding machine to form a diameter-enlarged holding member. This ensures the strength to withstand the shrinkage force (surface pressure) of the room temperature shrinkable tube. In particular, a thick room temperature shrinkable insulation cylinder for high-voltage cables has a large force (surface pressure) that tends to shrink in the radial direction. It has become.
However, when the fitting portion of the core string is ultrasonically welded, the welding strength varies depending on the quality of the molding material of the core string and variations in molding accuracy.

  If the welding strength of the core string is weak, the cylindrical shape of the expanded diameter holding member may collapse due to the surface pressure applied to the expanded diameter holding member by the cold-shrinkable tube. Moreover, the fitting state of the core string may be naturally released. In particular, when the cold-shrinkable tube is attached to the cable connection part, the core string is pulled out and unwound halfway, so that the cold-shrinkable tube is reduced in diameter and expanded from the middle. In addition, the shrinkage force of the cold shrinkable tube may act strongly on the core string at the end of the enlarged diameter holding member, and the cylindrical shape of the enlarged diameter holding member may collapse.

  On the other hand, if the strength by ultrasonic welding is excessive, the core string cannot be pulled out, the expanded diameter holding member cannot be removed, the normal temperature shrinkable tube cannot be reduced in diameter, and the construction becomes impossible. There is a risk.

  Therefore, in order to solve the above-mentioned problems, the present invention provides a diameter-enlarged holding member that can be endured by the uneven fitting of the core string even when the surface pressure of the cold-shrinkable tube is high, and An object is to provide a cold-shrinkable tube unit used.

  In order to solve the above problems, the diameter-enlargement holding member of the present invention expands the cold-shrinkable tube formed in a cylindrical shape by winding the core string in a spiral shape and fitting adjacent portions of the core string together. A diameter-enlargement holding member for holding in such a state that the core string includes a first flat surface, a second flat surface formed at a position opposite to the first flat surface, and the first flat surface. A first convex portion formed obliquely with respect to the first flat surface from the side and provided along the longitudinal direction of the core string, and the same as the first convex portion from the second flat surface side Formed obliquely projecting in the direction, the second convex portion provided along the longitudinal direction of the core string, and formed obliquely from the tip side of the first convex portion toward the first flat surface, A first recess provided along the longitudinal direction of the core string, and the second protrusion A second recess formed obliquely from the tip side toward the second flat surface and provided along the longitudinal direction of the core cord, and adjacent to the first convex portion of the core cord. And fitting the second concave portion of the portion of the core cord arranged in the same manner, and fitting the first concave portion of the core cord and the second convex portion of the core cord arranged adjacent to each other. It is characterized by comprising.

  Since the convex portion and the concave portion of the core string are obliquely fitted to the enlarged diameter holding portion, when the force is applied to the radially inner side of the enlarged diameter holding member, the inclined side surfaces of the convex portion and the concave portion come into contact with each other and resist. As a result, the expanded diameter holding member can withstand a larger surface pressure of the cold-shrinkable tube.

  In the present invention, the flat surface is used to mean a surface that is formed to be substantially flat as a whole when the core string is wound into a diameter expansion holding member. In the present invention, the first flat surface may have irregularities in a range that does not cause a problem on the inner surface of the cold-shrinkable tube. Further, the second flat surface may have irregularities within a range that does not cause a problem when the end portion of the core string is pulled, as will be described later, in order to remove the expanded diameter holding member.

  In the expanded diameter holding member of the present invention, it is desirable that the first concave portion and the second concave portion of the core string have a narrow width at the mouth compared to the width of the inner portion.

  As a result, a pulling resistance when the first convex portion is pulled out from the second concave portion and a pulling resistance when the second convex portion is pulled out from the first concave portion are generated. It can prevent more reliably that the fitting state naturally collapses. That is, it is possible to prevent a trouble that the core string is unfastened at a faster speed than the operator intends.

  The diameter-enlargement holding member of the present invention is formed so that tips of the first convex portion and the second convex portion of the core string swell smoothly, and the second concave portion and the first concave portion are fitted to each other. It is desirable that the inner part is formed so as to spread smoothly.

  As a result, the proof strength of the core string that can expand and hold the cold-shrinkable tube is increased, and the core string can be smoothly pulled out when the diameter-enlarged holding member is disassembled.

  The diameter-enlargement holding member of the present invention includes an angle at which the first convex portion is inclined with respect to the first flat surface, an angle at which the second convex portion is inclined with respect to the second flat surface, The angle at which the first recess is inclined with respect to the first flat surface and the angle at which the second recess is inclined with respect to the second flat surface are substantially equal to the angle θ, and the angle θ is 30 degrees or more and 70. It is desirable to be less than or equal to degrees.

By setting the angle θ to 30 degrees or more and 70 degrees or less, workability when removing the expanded core holding member by removing the wound core string and preventing natural collapse of the expanded diameter holding member It becomes easy to achieve both.

  In the expanded diameter holding member of the present invention, the angle θ is more preferably 40 degrees or more.

By setting the angle θ to 40 degrees or more, the pulling force required for unwinding the wound core string can be set to a more desirable magnitude.

  In the expanded diameter holding member of the present invention, it is more desirable that the angle θ is not less than 45 degrees and not more than 65 degrees.

By setting the angle θ to 45 degrees or more and 65 degrees or less, it is possible to reduce the variation in the drawing force even if the angle θ varies due to variations in the extrusion molding conditions.

  Further, the cold-shrinkable tube unit of the present invention is such that the cold-shrinkable tube unit is expanded in diameter by the above-mentioned diameter-enlarged holding member.

  According to this room temperature shrinkable tube unit, the state in which the room temperature shrinkable tube is expanded can be held more stably.

  ADVANTAGE OF THE INVENTION According to this invention, the diameter expansion holding member and room temperature shrinkable tube unit which can endure the surface pressure of a big cold shrinkable tube by fitting a core string can be provided.

It is a perspective view which shows preferable embodiment of the diameter expansion holding member which consists of a core string of this invention. It is sectional drawing which shows the fitting state of the part which the core string shown in FIG. 1 adjoins. It is a figure which shows the shape of the core string shown in FIG. 2, (A) is a right view, (B) is a front view, (C) is a rear view, (D) is a top view. It is a figure which shows the example of a dimension of the core string shown in FIG. It is sectional drawing which shows a mode that a core string is going to be pulled out. It is sectional drawing which shows the state from which the core string began to be pulled out from the state by which the diameter of the cold-shrinkable tube was held and the cold-shrinkable tube was in close contact with the outer peripheral surface of the power cable. It is a side view of the rotary roll used for formation of an enlarged diameter holding member. It is a top view of the rotary roll used for formation of a diameter expansion holding member. It is sectional drawing which shows the measurement position of the dimension and angle of the core string which was made as an experiment. It is a scatter diagram which shows the relationship between angle (theta) and drawing force. It is a figure which shows the shape of the core string used for the diameter expansion holding member which concerns on the 2nd Embodiment of this invention, (A) is a right view, (B) is a front view, (C) is a rear view, (D) Is a plan view.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view showing a preferred embodiment of an enlarged diameter holding member comprising a core string of the present invention.
A diameter-enlargement holding member 1 shown in FIG. 1 is a cylindrical member formed by winding a long core string 10 having a concavo-convex portion into a spiral shape by a core forming device (not shown). The expanded diameter holding member 1 is also called a spiral core, and the core string 10 has flexibility.

The core string 10 is required to be strong enough to withstand the force that the cold-shrinkable tube tends to shrink, and is formed of a material that is difficult to soften at the use environment temperature and can maintain the expanded state of the cold-shrinkable tube. The core string 10 is made, for example, by extrusion molding, and is made of an elastically deformable material, such as polypropylene resin or polyethylene terephthalate resin. The distal end portion 90 of the core string 10 passes through the enlarged diameter holding member 1 and is drawn out to the opposite side. This portion 90 is used as a drawn wire 101 that is pulled when the expanded diameter holding member 1 is removed from the cold-shrinkable tube.

In consideration of the following (1) and (2), the pulling force of the core string 10 is preferably 15 N or more. More preferably, it is good to set it as 30 N or more.
(1) Ensuring the strength that the expanded diameter holding member 1 is not crushed by the surface pressure of the room temperature shrinkable tube covered.
(2) Pulling out the core string 10 and preventing the core string 10 from being sandwiched between the tube and the cable connection part when the cold-shrinkable tube is attached to the cable connection part.
On the other hand, it is desirable that the drawing force is 110 N or less from the viewpoint of workability of the drawing work. More desirably, it is 70N or less.

  FIG. 2 shows a structural example of fitting of the core string 10 constituting the diameter expansion holding member 1 shown in FIG. 1, and is a perspective view having a cross section taken along the line BB of FIG. FIG. 3 shows the shape of the core string 10, (A) is a right side view, (B) is a front view, (C) is a rear view, and (D) is a plan view. In FIGS. 5B to 5D, no line is shown for the curved (curved surface) portion. The bottom view is the same as the plan view. The left side view is symmetric with the right side view. The shape of the core string is continuous from side to side in the front view. In FIG. 2, for simplification of the drawing, a part of the fitting structure of the core string 10 is shown as a representative. That is, in FIG. 2, the fitting state of the core string 10 of the part shown by the codes | symbols 11 and 12 in FIG. 1 is shown.

  As shown in FIGS. 2 and 3, the core string 10 has a relatively uniform wall pressure, and is formed in a 180-degree rotationally symmetric shape with the center point CL shown in FIG. 3 as the center.

  The parts 11 and 12 of the core string 10 shown in FIG. 2 have the same cross-sectional shape. The core string 10 includes a first flat surface 21 that is an outer peripheral surface of the diameter-enlargement holding member 1, a second flat surface 22 that is an inner peripheral surface, a first convex portion 23, a second convex portion 24, and a first concave portion 25. And a second recess 26. The first convex portion 23, the second convex portion 24, the first concave portion 25, and the second concave portion 26 are continuously formed in parallel along the longitudinal direction L of the core string 10.

  As shown in FIG. 3, the first flat surface 21 and the second flat surface 22 are formed parallel to the X direction with a distance S1 apart. The second flat surface 22 is a surface opposite to the first flat surface 21. The core string 10 has a width of a distance S2 in the X direction.

Here, the X direction coincides with the direction of the central axis of the enlarged diameter holding member 1 as shown in FIG. Further, the Y direction coincides with the radial direction of the enlarged diameter holding member 1.

A convex portion 31 is formed in a frame shape on the one end 21 </ b> B side of the first flat surface 21. The convex portion 31 has, for example, a ¼ circumferential curved surface portion. From the convex portion 31, the first convex portion 23 is formed so as to protrude obliquely downward as indicated by an arrow R1. The first protrusion 23 protrudes obliquely with respect to the first flat surface 21 from the first flat surface 21 side, and is provided continuously along the longitudinal direction L of the core string 10.

  As shown in FIG. 3, the tip portion 32 of the first convex portion 23 is formed in an arc shape so as to swell smoothly. An arc-shaped concave portion 33 is formed between the tip portion 32 and the convex portion 31.

  On the other end 21C side of the first flat surface 21, a convex portion 34 is formed in the shape of the back of the head. The convex portion 34 has, for example, a ¼ circumferential curved surface portion.

  On the other hand, as shown in FIG. 3, a convex portion 41 is formed in a hook shape on the one end portion 22 </ b> B side of the second flat surface 22. The convex portion 41 has a ¼ circumferential curved surface portion. As indicated by an arrow R2, the second convex portion 24 extends from the convex portion 41 obliquely with substantially the same inclination as the first convex portion 23, and protrudes upward. The second protrusion 24 protrudes obliquely with respect to the second flat surface 22 from the second flat surface 22 side, and is continuously provided along the longitudinal direction L of the core string 10.

  The tip portion 42 of the second convex portion 24 is formed in an arc shape so as to swell smoothly. An arc-shaped concave portion 43 is formed between the tip portion 42 and the convex portion 41.

  As shown in FIG. 3, a convex portion 44 is formed in a jaw shape on the other end 22 </ b> C side of the second flat surface 22. The convex portion 44 has a ¼ circumferential curved surface portion.

  The first concave portion 25 is formed obliquely from the distal end side of the first convex portion 23 toward the first flat surface 21, has a smooth back portion, and is continuous along the longitudinal direction L of the core cord 10. Is provided. The second concave portion 26 is formed obliquely from the distal end side of the second convex portion 24 toward the second flat surface 22, has a smooth back portion, and is continuous along the longitudinal direction L of the core cord 10. Is provided.

  As shown in FIG. 3, the first concave portion 25 is formed in the R3 direction between the tip portion 32 of the first convex portion 23 and the convex portion 44 of the second flat surface 22. Similarly, the second concave portion 26 is formed in the R4 direction between the tip portion 42 of the second convex portion 24 and the convex portion 34 of the first flat surface 21. As shown in FIG. 2, the arrows R1 and R4 and the arrows R2 and R3 are substantially parallel to each other.

In this example, R1 to R4 are inclined at substantially the same angle θ with respect to the X direction, that is, about 45 degrees to the left in FIG. That is, the first convex portion 23 and the first concave portion 25 are inclined from the first flat surface 21 toward the second flat surface 22 in a direction gradually away from an imaginary line in the Y direction passing through the center point CL. The 2nd convex part 24 and the 2nd recessed part 26 incline in the direction which leaves | separates gradually from the virtual line of the Y direction which passes through the center point CL toward the 1st flat surface 21 from the 2nd flat surface 22. As shown in FIG.

FIG. 4 shows an example of the dimensions of the cross-sectional shape of the core string 10 shown in FIG.
The distal end portion 32 of the first convex portion 23, the distal end portion 42 of the second convex portion 24, the inner portion of the first concave portion 25 and the inner portion of the second concave portion 26 in which they are fitted have a radius R of 1.25 mm. It is formed in an arc shape. Further, the center angle of these arcs is larger than 180 °, so that, as shown in FIG. 2, the width W1 of the narrowest portion in the mouth portion of the second recess 26 is fitted in the inner portion of the second recess 26. It is smaller than the width W2 of the widest portion of the first convex portion 23 to be performed. Similarly, the width W1 of the narrowest portion in the mouth portion of the first concave portion 25 is set to be smaller than the width W2 of the widest portion that fits in the back portion of the second convex portion 24.
As shown in FIG. 4, the convex portions 31 and 41, the convex portions 34 and 44, and the concave portions 33 and 43 have a ¼ arc shape with a radius R of 1.25 mm.

  2 and 3, the core string 10 has a relatively uniform wall pressure along the X direction, as shown by the distance S1 between the first flat surface 21 and the second flat surface 22. Since it is formed in a 180-degree rotationally symmetric shape with the center point CL shown as the center, it is easy to extrude, the smoothness of the first flat surface 21 and the second flat surface 22 is easily obtained, and the convex portion formed round And the shape of the recess can be stably formed.

As shown in FIG. 2, the adjacent portions 11 and 12 of the core string 10 are fitted together and are detachably connected to each other.
The first convex portion 23 of the portion 12 is fitted in the second concave portion 26 of the adjacent portion 11, and the second convex portion 24 of the portion 11 is fitted in the first concave portion 25 of the portion 12.

Moreover, as shown in FIGS. 4 and 2, the first convex portion 23 and the second concave portion 26, and the second convex portion 24 and the first concave portion 25 are diagonally fitted. The side surfaces of the convex portions 23 and 24 of the core string 11 and the side surfaces of the concave portions 26 and 25 are brought into contact with each other by the surface pressure of the cold-shrinkable tube applied in the direction, and the press contact force of the side surfaces suppresses the disengagement of these fittings.
Further, when the first convex portion 23 is pulled out from the second concave portion 26 and when the second convex portion 24 is pulled out from the first concave portion 25, it is possible to generate an appropriate pulling resistance. It can prevent that the mutual fitting state of the core string of the diameter expansion holding member 1 naturally collapses. That is, the fitting of the first convex portion 23 and the second concave portion 26 and the fitting of the second convex portion 24 and the first concave portion 25 can be reliably performed, and the fitting state is not easily released. Yes.

  Next, using the above-described expanded diameter holding member 1 composed of the core string 10, the expanded diameter holding method for expanding and holding the cold-shrinkable tube, and the core string 10 of the expanded diameter holding member 1 are pulled out to be cooled at room temperature. An operation for reducing the diameter of the tube will be described.

  First, a method for forming the enlarged diameter holding member 1 using the core string 10 will be described with reference to FIGS. FIG. 7 is a side view of the rotating roll 51 used for forming the enlarged diameter holding member 1, and FIG. 8 is a top view of the rotating roll 51. As shown in FIGS. 7 and 8, the core string 10 is supplied to the proximal end of a short cylindrical rotating roll 51 and wound in a spiral shape by the rotation of the rotating roll 51. The wound core string 10 is sequentially pushed out to the front end side of the rotary roll 51. When this becomes a predetermined length, it is cut into a cylindrical expanded diameter holding member 1 (see Japanese Patent Application Laid-Open No. 2004-328910). When the core string 10 is supplied to the rotary roll 51, the core string 10 is partially overlapped with the side edge of the core string 10 that has been wound first. The supplied core string 10 is pressed by the pressing roll 52 as necessary. Thereby, as shown in FIG. 2, the first convex portion 23 of the portion 12 is fitted into the second concave portion 26 of the adjacent portion 11, and the second convex portion 24 of the portion 11 is the first convex portion of the portion 12. It fits in the recess 25. In this embodiment, ultrasonic welding is not performed.

  As shown in FIG. 6 (A), the expanded diameter holding member 1 is disposed inside a cylindrical room temperature shrinkable tube 100. The cold-shrinkable tube 100 and the expanded diameter holding member 1 constitute a cold-shrinkable tube unit. The diameter expansion holding member 1 withstands the force (surface pressure) to be contracted by the cold-shrinkable tube 100 and expands and holds the cold-shrinkable tube 100 in diameter. Thus, in a state where the diameter expansion holding member 1 expands and holds the inner diameter of the cold-shrinkable tube 100, the first flat surface 21 of the core string 10 is in close contact with the inner peripheral surface of the cold-shrinkable tube 100. The The room temperature shrinkable tube 100 is a cylindrical insulator made of an elastic material such as rubber such as silicone rubber or ethylene propylene rubber.

  As shown in FIG. 1 and FIG. 6A, the distal end portion 90 of the core string 10 is drawn out in the drawing direction T through the enlarged diameter holding member 1 as a drawn wire 101 from the tip end portion of the enlarged diameter holding member 1. ing.

Next, with reference to FIG. 6, a method of using the unit composed of the cold-shrinkable tube 100 and the expanded diameter holding member 1 will be described. As shown in FIG. 6A, the unit is disposed around the connection portion 120 of the power cable. The power cable connecting portion 120 is a portion connecting the first power cable 111 and the second power cable 112. The first power cable 111 has a cable insulator 121 and a cable conductor 123, and the second power cable 112 has a cable insulator 122 and a cable conductor 124.
The cable conductor 123 and the cable conductor 124 are electrically and mechanically connected using a connection sleeve 125. An insulating material 126 is disposed around the cable conductors 123 and 124 and the connection sleeve 125.

  As shown in FIG. 6 (A), the inner diameter M of the expanded diameter holding member 1 is set larger than the outer diameter N of the first power cable 111 and the second power cable 112. Thereby, the diameter expansion holding member 1 can be arrange | positioned around the connection part 120 of an electric power cable, holding the normal temperature shrinkable tube 100 in the diameter expansion state.

  When the drawing wire 101 shown in FIG. 6 (A) starts to be drawn along the drawing direction T of the enlarged diameter holding member 1 as shown in FIG. 6 (B), the adjacent portions 11 and 12 shown in FIG. The state changes as shown in FIG. That is, as shown in FIG. 5, when the portion 11 starts to be pulled out along the pulling direction T with respect to the portion 12, the first convex portion 23 of the portion 12 is the mouth portion of the second concave portion 26 of the portion 11. Since the convex portion 34 of the portion 11 is pushed open in the H direction, the second concave portion 26 of the portion 11 is expanded to the width W3.

  Similarly, as shown in FIG. 5, the second convex part 24 of the part 11 pushes and opens the convex part 44 of the part 12, which is the mouth part of the first concave part 25 of the part 12, in the J direction. The first recess 25 is expanded to a width W3.

  As shown in FIG. 5, the first convex portion 23, the second concave portion 26, the second convex portion 24, and the first concave portion 25 are continuously formed along the longitudinal direction L of the core string 10. As shown in FIG. 6A, the core string of the expanded diameter holding member 1 can be pulled out with a constant force along the pulling direction T, and the mutual fitting state of adjacent portions is along the T direction. Will be solved sequentially.

  When the core string is unwound, the portion 118 of the cold-shrinkable tube 100 contracts and contracts as shown in FIG. 6B, so that the inner surface of the portion 118 of the cold-shrinkable tube 100 becomes the cable insulator. It is closely attached to the outer peripheral surface of 121.

Further, when the core string of the expanded diameter holding member 1 is pulled out in the pulling direction T, all the core string 10 is finally unwound, and the expanded diameter holding member 1 contracts at room temperature as shown in FIG. It is removed from the inside of the sex tube 100. The room temperature shrinkable tube 100 contracts and adheres closely to the outer peripheral surface of the cable insulator 121, the outer peripheral surface of the insulator 126, and the outer peripheral surface of the cable insulator 122.
In this way, the diameter expansion holding member 1 fulfills the function of expanding the diameter of the cold-shrinkable tube 100. Cold shrinkage means that the tube 100 shrinks at room temperature as described above.

  As described above, the core string 10 of the expanded diameter holding member 1 has a cross-sectional shape as shown in FIGS. That is, the convex portions 23 and 24 and the concave portions 26 and 25 are fitted obliquely. That is, as shown in FIG. 2, the first convex portion 23 and the second concave portion 26 have a fitting angle θ of about 45 degrees obliquely. Similarly, the second convex portion 24 and the first concave portion 25 are The fitting angle θ is about 45 degrees.

For this reason, when a force is applied to the radially enlarged holding member 1 on the radially inner side, the inclined side surfaces of the convex portions 23 and 24 and the concave portions 26 and 25 are in contact with each other and resist. As a result, the expanded diameter holding member 1 can withstand even the surface pressure of the cold-shrinkable tube 100 is increased, so that it is possible to eliminate the welding of the adjacent portions 11 and 12 of the core string 10. .

  Further, in the expanded diameter holding member 1, the first concave portion 25 and the second concave portion 26 of the core string 10 have a width W1 at the mouth that is smaller than the width W2 of the inner portion, so that as shown in FIG. When the portion 11 starts to be pulled out along the pulling direction T with respect to the portion 12, the convex portion 34 in which the first convex portion 23 of the portion 12 is the mouth portion of the second concave portion 26 of the portion 11 is shown in FIG. Since it pushes open in the direction, the width | variety of the narrow part of the 2nd recessed part 26 spreads to W3. Similarly, since the 2nd convex part 24 pushes open the convex part 44 in the opening | mouth of the 1st recessed part 25 to a J direction, the width | variety of the narrow part of the 2nd recessed part 26 spreads to W3.

  As a result, a pulling resistance is generated when the first convex portion 23 is pulled out from the second concave portion 26, and a pulling resistance is generated when the second convex portion 24 is pulled out from the second concave portion 25. It is possible to prevent a trouble that the core string 10 is unfastened at a speed faster than intended.

Furthermore, the core string 10 of the diameter-enhancement holding member 1 has a circular shape such as a circular arc shape at the front ends of the first convex portion 23 and the second convex portion 24, and the first concave portion 25 and the second concave portion 26 Since the inner part has a round shape such as an arc shape, the core string 10 can be smoothly pulled out when the diameter-enlargement holding member 1 is disassembled.

  As described above, the diameter-enlargement holding member of this embodiment can secure a proof stress capable of holding a larger room temperature shrinkable tube 100 in an expanded state without using ultrasonic welding, and can also maintain a core string. It is possible to appropriately design the pulling force when removing 10 by removing 10.

  In this embodiment, since it is not necessary to use ultrasonic welding when the core string 10 is wound in a spiral shape to form the expanded diameter holding member 1, the “core when excessive ultrasonic welding has occurred in the past has occurred. It is possible to avoid the problem that the cold shrinkable tube cannot be reduced in diameter without the string being pulled out, and the construction becomes impossible.

  Furthermore, since the expanded diameter holding member 1 does not need to be welded, even if there are variations in the characteristics of the raw material of the core string 10, the fitting strength of the core string 10 is stable, and the productivity of the expanded diameter holding member is increased. Will improve. That is, it is possible to avoid the inconvenience that the welding strength cannot be obtained due to variations in characteristics of raw materials such as polypropylene.

  Moreover, since it is not necessary to perform ultrasonic welding with respect to the fitting part of the core cords 10, the problem of variations in the pressure resistance of the expanded diameter holding member 1 due to variations in the molding accuracy of the core cords 10 can be avoided.

  As is clear from the cross-sectional shape of the core cord 10, the wall thickness is relatively uniform, and since it is 180-degree rotationally symmetric about the center point CL shown in FIG. 21 and the smoothness of the 2nd surface 22, the shape of the 1st convex part 23 and the 2nd convex part 24 which were formed round, and the 1st recessed part 25 and the 2nd recessed part 26 can be shape | molded stably. In the cross-sectional shape of the core string 10, since a sharp corner portion is not formed, adjustment at the time of extrusion molding is relatively easy.

(Experimental example)
Seven types of core strings 10 were manufactured by extrusion molding, in which the angle θ formed with the X axis of the first convex portion 23, the first concave portion 25, the second convex portion 24, and the second concave portion 26 was changed. The material of the core string 10 was polypropylene E-253GT manufactured by Prime Polymer Co., Ltd. These core strings 10 were spirally wound with the apparatus shown in FIGS. 7 and 8 to form the expanded diameter holding member 1 (inner diameter 170 mm), and the respective moldability was examined. Further, as shown in FIG. 1, the distal end portion 90 of the core string 10 is pulled out as a drawn wire rod 101 from the manufactured expanded diameter holding member 1 and is pulled to pull the drawn wire rod 101 to unwind the expanded diameter holding member 1. The force was measured.

◎ 引抜き力が特に望ましい範囲（３０−７０Ｎ）に入った。
○ 引抜き力が良好であった。
△ 引抜き力が望ましい範囲（１５−１１０Ｎ）に入った。
× 引抜き時の手応えが弱く、作業時に自然崩壊の発生が懸念される。 FIG. 9 shows the measurement positions of the dimensions and angles of the prototype core string 10, and Table 1 shows the respective measurement results. Here, the angle θ is an average value of the angles θ1 and θ2 shown in FIG. Moreover, the average value of the force required to unravel the expanded diameter holding member 1 is shown as the pulling force.

◎ The pulling force is in a particularly desirable range (30-70N).
○ The pulling force was good.
Δ: The pulling force was in the desired range (15-110N).
× The response at the time of drawing is weak, and there is a concern about the occurrence of natural collapse during work.

Based on the measurement results shown in Table 1, FIG. 10 shows a scatter diagram when the horizontal and axis are the angle θ and the vertical axis is the pulling force. FIG. 10 is a scatter diagram showing the relationship between the angle θ and the pulling force. From the figure, it is preferable to set the angle θ to 30 degrees to 70 degrees, and more preferable to set the angle θ to 40 degrees to 70 degrees so that the pulling force is desirably in the range of 15N to 110N. Furthermore, it is particularly preferable that the angle θ is 45 degrees to 65 degrees so that the pulling force is in the range of 30 N to 70 N. From FIG. 10, it can be seen that by setting the angle θ to 45 degrees to 65 degrees, the variation in the drawing force can be reduced even if the angle θ varies due to variations in the extrusion molding conditions.

(Embodiment 2)
A second embodiment according to the diameter expansion holding member of the present invention will be described below. The expanded diameter holding member of the present embodiment is formed using a core string 10A shown in FIG. 11A and 11B are views showing the shape of the core string 10A, where FIG. 11A is a right side view, FIG. 11B is a front view, FIG. 11C is a rear view, and FIG. In FIGS. 5B to 5D, no line is shown for the curved (curved surface) portion. The bottom view is the same as the plan view. The left side view is symmetric with the right side view. The shape of the core string is continuous from side to side in the front view. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The inclination angle θ of the first convex portion 23, the second convex portion 24, the first concave portion 25, and the second concave portion 26 of the core string 10A is 55 degrees with respect to the X direction.

In addition, the core string 10A is provided with hook-shaped return portions 23A and 24A on the inner sides of the first convex portion 23 and the second convex portion 24, respectively. The first recess 25 and the second recess 26 are provided with recesses 25A and 26A into which the return portions 24A and 23A are fitted, respectively. The expanded diameter holding member formed by the core cord 10A is used when the convex portions 23 and 24 are removed from the concave portions 26 and 25 by the catching of the return portion 23A and the recess portion 26A, and the return portion 24A and the recess portion 25A, respectively. Since the resistance is increased, the resistance when the core string 10 is pulled out can be increased and the response can be increased.

  In this embodiment, the curved surfaces of the first flat surface 21 and the second flat surface 22 at one end 21B, 22B and the other end 21C, 22C are made as small as possible without causing any trouble when the core string 10A is extruded. .

By the way, this invention is not limited to the said embodiment, A various modified example is employable.
For example, the shape of the 1st convex part and 2nd convex part of a core string is not specifically limited if the front-end | tip part is smoothly inflated and formed not only in circular arc shape. Moreover, the shape of a 1st recessed part and a 2nd recessed part is suitable for the shape of a 2nd convex part and a 1st convex part, and should just be able to fit together, and is not specifically limited.
The first convex part and the second convex part need only have the same inclination direction, and the inclination angle θ may be different.
Further, the diameter-enlarged holding member of the present invention includes an auxiliary welded core string, for example, an end of the diameter-enlarged holding member to prevent the core string from being unwound from the end of the diameter-enlarged holding member. Also included is a core string welded at the part.

DESCRIPTION OF SYMBOLS 1 Expanded diameter holding member 10, 10A Core string 11,12 part 21 1st flat surface 22 2nd flat surface 23 1st convex part 24 2nd convex part 25 1st recessed part 26 2nd recessed part 101 Drawing wire

Claims (7)

The core string is wound in a spiral shape, and formed into a cylindrical shape by fitting adjacent parts of the core string, an expanded diameter holding member for holding the cold-shrinkable tube in an expanded state,
The core string is
A first flat surface;
A second flat surface formed at a position opposite to the first flat surface;
A first protrusion formed obliquely with respect to the first flat surface from the first flat surface side and provided along the longitudinal direction of the core string;
A second convex portion that is formed to project obliquely in the same direction as the first convex portion from the second flat surface side, and is provided along the longitudinal direction of the core string,
A first recess formed obliquely from the distal end side of the first projection toward the first flat surface and provided along the longitudinal direction of the core string;
A second recess formed obliquely from the distal end side of the second convex portion toward the second flat surface and provided along the longitudinal direction of the core string;
With
The first convex portion of the core cord and the second concave portion of the core cord portion arranged adjacent to each other are fitted together, and the first concave portion of the core cord is arranged adjacent to the first concave portion. A diameter-enlargement holding member comprising a core string, wherein the diameter-enhancement holding member is configured by fitting the second convex part of the core string.   The diameter-enlarged holding member comprising a core string according to claim 1, wherein the first recess and the second recess have a width at the mouth that is smaller than a width of a back portion.   The ends of the first and second convex portions of the core string are formed so as to swell smoothly, and the second concave portion and the inner portion of the first concave portion in which these are fitted are smoothly spread. The diameter expansion holding member according to claim 2, wherein the diameter expansion holding member is formed.   An angle at which the first convex portion is inclined with respect to the first flat surface, an angle at which the second convex portion is inclined with respect to the second flat surface, and a first concave portion with respect to the first flat surface And the angle at which the second recess is inclined with respect to the second flat surface is substantially equal to the angle θ, and the angle θ is not less than 30 degrees and not more than 70 degrees. The diameter expansion holding member according to any one of claims 1 to 3.   The diameter expansion holding member according to claim 4, wherein the angle θ is 40 degrees or more.   The diameter expansion holding member according to claim 5, wherein the angle θ is not less than 45 degrees and not more than 65 degrees. A room-temperature-shrinkable tube unit in which the diameter-enlarged holding member according to any one of claims 1 to 3 is inserted into a hole of the room-temperature-shrinkable tube to expand the diameter.

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