JP3412074B2 - Manufacturing method of metal wire coil / plastic tube composite sheath - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite sheath of a metal wire coil and a plastic tube for covering a suspended steel wire of a bridge or the like. 2. Description of the Related Art A steel cable for suspending a long bridge or the like bridged on the sea or the like is designed to withstand a large suspending load, has a large tensile strength, and is suspended between supporting columns at a predetermined sag. For this reason, a large number of steel wires are bundled together to form a large-diameter steel wire.However, this steel wire is constantly exposed to sea breeze, and if the outer surface of the steel wire remains bare, the wire will be corroded. It is necessary to prevent corrosion of the steel cable because there is a danger that the tensile strength will be reduced and the tensile strength will be reduced. If this anticorrosion layer is formed by applying an anticorrosion paint to the surface of the steel cable, the steel cable suspending the bridge etc. is always exposed to relatively strong winds, so that the anticorrosion coating film is stained and peeled off in a short period of time. Periodical repainting is required, which makes repainting operations difficult and costly due to work at heights. An anticorrosion method of covering the outer periphery of a steel cord with a plastic sheath so that the anticorrosion can withstand use for a long time has been performed. [0003] When a plastic sheath is put on the outer periphery of the above-mentioned large-diameter steel cord, a plastic tape is directly wound around the outer periphery of the steel cord, or a plastic sheath is extrusion-coated. In either method, since the diameter of the steel cord is large, the device becomes large and the cost increases. For this reason, if a method is adopted in which a plastic sheath molded in a hollow shape is drawn and covered so as to cover the outer periphery of a large-diameter steel cable, friction between the outer peripheral surface of the steel wire group and the inner peripheral surface of the plastic sheath is large. There is a problem that the drawing operation is difficult. The present invention solves the above problems and provides a method of manufacturing a metal wire coil / plastic tube composite sheath that can be easily covered on the outer periphery of a large-diameter steel cable or the like for suspending a bridge or the like. It is intended to do so. [0005] In order to achieve the above-mentioned object, a method of manufacturing a metal wire coil / plastic tube composite sheath according to the present invention comprises forming a metal wire spirally into a metal wire coil. The first step (A) of continuously feeding 1
And a plastic strip 2 on the outer periphery of the metal wire coil 1.
And the coil wire 1 is inserted into the coil fitting groove 25 on the inner periphery of the spiral plastic strip 2.
A second step (B) of exposing the inner peripheral side portion of the coil to the outside of the groove 25 and fitting the same, and an adjacent edge of the adjacent spiral plastic strip 2 attached to the outer periphery of the metal wire coil 1 Third step of forming a composite tube 3 of a metal filament coil 1 and a spiral plastic strip 2 by joining
(C) and a fourth step (D) of extruding and coating a plastic jacket 4 on the outer periphery of the above-mentioned metal wire coil / spiral-shaped plastic strip composite tube 3.
This is a method characterized in that a plastic tube composite sheath 5 is manufactured. The metal wire coil 1 with the plastic strip 2 reinforces a hollow tubular plastic sheath from the inside. By joining the adjacent edges of the spiral plastic strip 2 attached to the outer periphery of the metal filament coil 1, the adjacent plastic strip 2 wound in a spiral shape is joined.
No separation gap is generated between them, so that the shape of the hollow tube is maintained, and the outer periphery thereof can be extrusion-coated with a uniform plastic jacket 4. When the metal wire coil / plastic tube composite sheath 5 is pulled so as to cover the outer periphery of the steel cable, the frictional resistance is large if the inner peripheral surface of the plastic directly contacts the outer peripheral surface of the steel cable.
The inner peripheral side portion of the metal wire coil is exposed and protrudes from the lower surface 23 of the 22, and the exposed protruding metal wire portion comes into contact with the outer peripheral surface of the steel cord, so that the frictional resistance at the time of retraction is reduced and slippage occurs. This makes it easy to pull in and cover the outer circumference of the large-diameter steel cable. An embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, in the method for producing a metal wire coil / plastic tube composite sheath of the present invention, the metal wire coil 1 is continuously fed in the metal wire coil continuous feeding step (A) of the first step. And send it out. In the plastic strip / metal wire coil coiling and fitting step (B) of the second step, a plastic strip 2 is spirally attached to the outer periphery of the metal wire coil 1 so as to form the spiral plastic strip. The coil wire 1 is fitted in the coil fitting groove 25 of the strip 2 by exposing the inner peripheral side of the coil to the outside of the groove 25. In the plastic strip adjacent edge joining step (C) of the third step, the adjacent edges of the plastic strip 2 are joined to the outer periphery of the metal wire coil 1 to join the metal wire coil 1 and the spiral shape. The composite tube 3 of the plastic strip 2 is formed. 4th step plastic extrusion extrusion coating step (D)
In the above, the outer circumference of the metal wire coil / plastic strip composite tube 3 is extrusion-coated with a plastic jacket 4 to form a metal wire coil / plastic tube composite sheath 5.
To manufacture. In the first step (A), the metal wire coil is continuously fed from the metal wire drum 12 to the spiral forming section 10 as shown in FIG. While continuously forming the metal filament 11 into a spiral in the spiral molding part 10, as shown in FIG. 2, the metal filament 11 is wound around the guide shaft 13 having a circular cross section at a pitch P to form a coil. The metal wire coil 1 is connected to the guide shaft 13
While being rotated around, a continuous feeding is performed in the direction of the arrow toward the second step (B) of the next step shown in FIG. In the plastic strip / metal wire coil joining step (B) shown in FIG. 1 of the second step, the plastic strip extruder 33 extrudes the low-density polyethylene or other plastic strip 2. It is molded and fed to a plastic strip attachment part 30 composed of a plastic strip attachment part 31 and a plastic strip fitting part 32. The plastic strip 2 is spirally attached to the outer periphery of the metal wire coil 1 to be fed, and the metal wire coil 1 is inserted into the coil fitting groove 23 of the plastic strip 2 at the plastic strip fitting portion 32. The inner circumferential side of the coil is exposed to the outside of the groove 25, and fitted and fitted. The cross-sectional shape of the plastic strip 2 is as follows:
As shown in FIG. 3 showing the end face of the plastic strip 2 of the first embodiment, a central trapezoidal ridge 22 is provided at the center of the lower surface of the central strip 21 and extends in the longitudinal direction.
In the center of the lower surface 23 of the coil 22, a coil fitting groove 25 of a circular groove having a diameter φ into which the wire of the metal wire coil 1 can be fitted is continuously provided in the longitudinal direction. Is the trapezoidal protrusion
23, a narrow opening 24 which is opened in the longitudinal direction is provided, the opening width S of the narrow opening 24 is smaller than the diameter φ of the circular groove of the coil fitting groove 25, and the metal of the metal wire coil 1 is formed. The opening width is formed so that the filament can be fitted. On both left and right edges of the central band portion 21, a lower joining edge piece 26 having a thickness d which is half the thickness of the band portion 21 is provided in the longitudinal direction, and the same height d is provided on the upper side. Is formed on the right side edge, and an upper joining edge piece portion 28 having a thickness d that is half the thickness of the band plate portion 21 is provided in the longitudinal direction, and a lower portion having the same height d is provided below the upper joining edge piece portion 28. The side step 29 is formed, and the width W1 of the lower joining edge piece 26 and the width W2 of the upper joining edge piece 28 are formed to be the same width. 27a is a corner edge of the upper step 27, and 28a is a corner edge of the upper joining edge piece 28. One example of this plastic strip 2 is the thickness of the joining edge pieces 26 and 28 on both sides, the height d of the steps 27 and 29 = 1 mm, the two joining edge pieces 2
6, 28 width W1, W2 = 5mm, plastic strip 2 width W =
25 mm, height H of trapezoidal ridge 22 = 3 mm, height from lower surface 23 of trapezoidal ridge 22 to center of circular groove of coil fitting groove 25
h0 = 1 mm, diameter φ of circular groove of coil fitting groove 25 = 2.9
mm, and the opening width S of the narrow opening 24 is about 2 mm. Also, the diameter r of the wire of the metal wire coil 1 is the above-mentioned coil fitting groove.
It is a diameter that can fit within 25. The plastic strip attachment part 31 of the plastic strip attachment fitting part 30 to which the plastic strip 2 extruded by the extruder 33 in the above-described shape is fed is shown in FIG. As described above, the plastic strip 2 is spirally attached to the outer periphery of the metal wire coil 1. The metal filament coil 1 formed in the first step, wound around the guide shaft 13 and fed in the direction of the arrow while rotating is provided on the guide shaft 13.
Is fed at a predetermined pitch by a guide groove or other appropriate positioning means, and is fed along the outer periphery of the metal wire coil 1 so that the plastic strip 2 fits in the coil of the central trapezoidal ridge 22. It is fed with the joint groove 25 facing the metal wire coil 1. 31a is an example of a guide means for the plastic strip 2. The plastic strip 2 fed along the outer periphery of the metal wire coil 1 is used to guide the coil fitting groove 25 of the plastic strip 2 to the metal. It is positioned so as to face and contact the outer side surface of the filament coil 1 correctly. As described above, in the plastic strip attachment portion 31, the coil fitting groove 25 of the plastic strip 2 is opposed to the outer periphery of the metal wire coil 1 and spirally attached to the plastic strip 2 and the metal. In the wire coil 1, the coil fitting groove 25 is fitted into the metal wire coil 1 in the plastic strip fitting part 32 of the plastic strip abutting fitting part 30. As shown in FIG. 5, the plastic strip fitting portion 32 includes means for guiding the plastic strip 2, for example, a pressing guide plate 32a, etc., and is used for positioning means on the peripheral surface of the guide shaft 13, for example, for the positioning guide groove 13a. Metal wire coil 1
The plastic strip 2 having the central trapezoidal ridge 22 attached to the outer periphery of the metal filament coil 1 is guided by the pressing guide plate 32a, while the trapezoidal ridge 22 of the plastic strip 2 is When the narrow opening 24 of the coil fitting groove 25 that opens on the lower surface is pressed against the outer periphery of the metal wire coil 1, the inner peripheral portion of the coil is exposed outside the narrow opening 24, and the trapezoidal ridge 22 is formed. The metal wire coil 1 is fitted into the coil fitting groove 25 while projecting from the lower surface 23. As shown in FIG. 6, the wire of the metal wire coil 1 fitted in the coil fitting groove 25 has at least 2/3 or more of the thickness of the wire. Mating groove
25 and exposed through the narrow opening 24 to form the trapezoidal ridge 22
Slightly projecting downward from the lower surface 23 of the. Its narrow opening
An example of the exposed protrusion height h1 of the wire of the metal wire coil 1 at 24 is a height h0 = 1 mm from the lower surface 23 of the trapezoidal ridge 22 to the center of the circular groove of the coil fitting groove 25, and the coil fitting When the diameter φ of the circular groove of the joint groove 25 is 2.9 mm, h1 ≒ 1.4 to 1.5 mm. The composite spiral strip of the metal wire coil 1 and the spiral plastic strip 2 fitted and connected to the coil fitting groove 25 as described above rotates along the peripheral surface of the guide shaft 13. While being advanced in the direction of the arrow in FIG. 1, it is fed into the adjacent plastic strip edge joint 40 in the next plastic strip adjacent edge bonding step (C). At the adjacent plastic strip edge joint 40, as shown in FIG. 7, the adjacent plastic strip 2 of the composite spiral strip which is successively transferred and fed on the peripheral surface of the guide shaft 13 successively.
The joining edge pieces of the respective side edges are overlapped and joined. This joining is performed, for example, by rotating on the peripheral surface of the guide shaft 13 together with the metal filament coil 1 while lowering the right side edge 29 of the preceding spiral plastic strip 2A (29 is shown in FIG. 3).
The lower joining edge piece 26 of the left edge of the spiral-shaped plastic strip 2B is placed on the upper joining edge piece 28 of the right edge of the leading strip 2A and the lower side of the left edge of the trailing strip 2B. The joining edge pieces 26 are overlapped, and similarly, the upper joining edge piece 28 on the right edge of the spiral plastic strip 2B and the lower joining edge piece 26 on the left edge of the spiral plastic strip 2C that follow. The joining portions of the upper and lower joining edge pieces of the adjacent plastic strips sequentially joined in this way are joined by the joining device 41. The bonding device 41 uses a fusion device that heats and fuses the plastic plate pieces by, for example, heating with infrared light or appropriate electric heating or the like. The adjacent edge joints 268 are formed by heat fusion, and an adhesive may be applied between the upper and lower joining edge pieces 28 and 26 as necessary. In this way, the adjacent edges of the adjacent plastic strips 2 are joined to form a composite tube 3 of a metal wire coil and a spiral plastic strip. As described above, the metal wire coil / spiral-shaped plastic strip composite tube 3 in which the adjacent plastic strips 2 are joined at the adjacent edge joint portions 268 in the third step,
The outer peripheral surface of the guide shaft 13 is sent to the plastic jacket extrusion section 50 in the plastic jacket extrusion coating step (D) of the next step shown in FIG. The outer periphery of the plastic strip composite tube 3 is extruded and coated with an extrusion-coated plastic jacket 4 such as low-density polyethylene, for example, with a coating thickness of about 3 mm and an outer diameter of 76 mm to 115 mm. FIG. 8 is a cross-sectional view showing a composite metal wire coil / plastic tube sheath 5 for a bridge hanging steel cable of the present invention manufactured as described above. As described above, the metal wire coil / plastic tube composite sheath 5 in which the outermost layer is extruded and covered with the plastic jacket 4 is taken out by a suitable take-out means such as a caterpillar take-up device and cut into a fixed length. The metal wire coil / plastic tube composite sheath 5 manufactured as described above is drawn over the outer periphery of a steel cable in which a group of steel wires for hanging a bridge are bundled. When the inner surface of the plastic strip on the inner circumference of the hollow sheath is directly in contact with the outer circumference of the steel cord when the steel strip is drawn in so as to cover the outer circumference of the steel strip, the frictional resistance increases, but the lower surface 23 of the trapezoidal ridge 22 of the plastic strip 2 increases. Since the metal wire coil 1 is exposed and protrudes from the outer surface of the steel cable, the exposed metal wire portion comes into contact with the outer peripheral surface of the steel cable. It is possible to easily pull in and cover the outer periphery of the steel cable. FIG. 9 shows a second embodiment of the plastic strip 2, and the same reference numerals as those in FIG. 3 indicate the same parts. 22 is a central trapezoidal ridge, 23 is its lower surface, 25 is a coil fitting groove,
Numeral 24 denotes a narrow opening of the coil fitting groove 25, 26 and 28 denote joining edge pieces on both side edges, and 27 and 29 denote stepped portions. In the plastic strip 2 of the second embodiment, the left side joining edge 26 is provided on the upper side, the right side joining edge 28 is provided on the lower side, and the left side upper joining edge 26 is provided on the left side. Short axis 26b protruding downward on the lower surface
A hemispherical locking head 26a is provided at the lower end of the upper surface, and the upper surface of the lower joining edge piece 28 on the right side edge has an opening upward in diameter to which the locking head 26a is fitted and locked. Stop hole 28a and its small diameter opening
28b. As described above, the locking head 26a and the locking hole 28a are provided on the upper and lower joining edge pieces 26, 28 on both the left and right sides.
The plastic strip 2 of this embodiment is different from the plastic strip attachment part 31 of the plastic strip attachment fitting part 30 in the plastic strip / metal wire coil attachment fitting step (B) of the second step. The fitting of the metal wire coil 1 into the coil fitting groove 23 along the outer circumference of the metal wire coil 1 in the plastic strip fitting portion 32 is the same as that of the plastic strip 2 of the first embodiment. As in the above case, in the adjacent plastic strip edge joining portion 40 in the plastic strip adjacent edge joining step (C) of the third step, the lower joining edge piece portion 28 on the right edge of the preceding plastic strip. The upper joining edge piece 26 of the left edge of the succeeding plastic strip is superimposed on the plastic strip, and the locking head 26a protruding downward is fitted into the locking hole 28a opening upward, whereby the preceding plastic strip is inserted. Adjoining edge between strip and subsequent plastic strip Joining the parts. In the following fourth step (D), the plastic jacket 4 is extruded and coated on the outer periphery of the composite tube 3 of the metal wire coil / plastic strip to which the adjacent joining edge pieces are joined. The composite wire / plastic tube composite sheath 5 is formed and cut to a fixed length in the same manner as the plastic strip 2 of the first embodiment. In the embodiment of the method for producing a metal wire coil / plastic tube composite sheath of the present invention shown in FIG. 1 described above, the first step (A) of continuous feeding of the metal wire coil and the second step
Plastic strip and metal wire coil splicing and fitting process
(B), the third step of joining the plastic strip adjacent edge (C)
And the fourth step (D), which is a plastic jacket extrusion coating step,
Although the steps are continuous, an appropriate step may be discontinuous as necessary, for example, the first step and the second step or the third step and the fourth step may be discontinuous. As described above, according to the method of the present invention, the plastic strip is attached to the metal wire coil and the inner circumferential portion of the metal wire coil is inserted into the coil fitting groove on the inner circumference of the wire. Was exposed and fitted, and the outer periphery of the composite tube in which the adjacent edges of the plastic strip were joined was extrusion-coated with a plastic jacket to produce a metal wire coil / plastic tube composite sheath, so that a hollow tubular A uniform plastic jacket can be extrusion-coated on the outer periphery of the plastic sheath,
A composite sheath that can withstand long-term use can be obtained as a protective sheath for a steel cable or the like that suspends a bridge or the like. Further, when the metal wire coil / plastic tube composite sheath is pulled in so as to cover the outer periphery of the steel cable, the metal wire coil projecting and exposed on the inner periphery of the composite cable comes into contact with the outer peripheral surface of the steel cable. The frictional resistance at the time of pulling in becomes small, the slipping becomes easy, and it becomes possible to easily pull in and cover the outer circumference of the large diameter steel cable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing one embodiment of the method of the present invention. FIG. 2 is a view showing a continuous feeding step of a metal wire coil of a first step. FIG. 3 is a first view of a plastic strip. FIG. 4 is an explanatory view of a plastic strip attachment part in a second step. FIG. 5 is an explanatory view of a plastic strip fitting part in a second step. FIG. 6 is a metal wire of a plastic strip. FIG. 7 is a view showing a state in which a strip coil is fitted. FIG. 7 is an explanatory view of a plastic strip adjacent edge joining step in a third step. FIG. 8 is a partial cross-sectional view of a metal wire coil / plastic tube composite sheath of the present invention. Sectional view of a second embodiment of a plastic strip [Description of symbols] 1: Metal wire coil 2: Plastic strip 3: Metal wire coil spiral plastic strip composite tube 4: Plastic jacket 5: Metal Wire coil / plastic tube composite sheath 25: Coil fitting groove 268 of plastic strip: Strip edge joint of plastic strip A: First step B: Second step C: Third step D: Fourth step

Continuation of front page (56) References JP-A-57-57634 (JP, A) JP-A-52-36827 (JP, A) JP-A-59-144686 (JP, A) JP-A-61-231291 (JP) JP-A-61-250204 (JP, A) JP-A-1-190861 (JP, A) JP-A-1-190803 (JP, A) JP-B-51-17990 (JP, B1) JP-B-A1 43-21978 (JP, B1) Jikken 54-40471 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 69/00-69/02 B29C 47/00-47 / 96 B29D 31/00 E01D 11/00 F16L 11/00-11/18

Claims (1)

(57) [Claims 1] A first step of forming a metal wire spirally and continuously feeding a metal wire coil, and a plastic band around the outer periphery of the metal wire coil. A second step of fitting the strip in a spiral shape and fitting the coil wire into the coil fitting groove of the strip by exposing the inner peripheral portion of the coil outside the groove; A third step of joining adjacent edges of the plastic strip to form a metal wire coil / spiral-shaped plastic strip composite tube, and a plastic jacket on an outer periphery of the metal wire coil / spiral-shaped plastic strip composite tube. And a fourth step of extrusion-coating the composite wire.