Patent Abstract:
The invention relates to a composite twisted cable formed by impregnating carbon fibers with thermoplastic resin, and provides a fiber composite twisted cable which allows downsizing of a reel by being easy to be bent, can be transported to mountain areas which is normally hard to achieve a transport with a large vehicle, is hard to be curled, and is superior in workability. It is a cable having 1×n structure which is formed by impregnating bundles of carbon fibers with thermosetting resin, then twisting a plurality of strands each formed by covering an outer periphery of the bundle with a fiber, and then curing the thermosetting resin by applying the heat treatment, and a core strand and side strands which constitute the cable are separated and independent without being bonded so as to allow independent behavior of the respective strands when the cable is bent.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a fiber composite twisted cable and, more specifically, to a twisted cable in which carbon fibers and thermosetting resin as a matrix are combined. 
     2. Description of the Related Art 
     Among high-strength low ductility fibers, carbon fibers have characteristics such as light weight, high corrosion resistivity, non-magnetic property, high coefficient of thermal conductivity, ultralow coefficient of thermal expansion, high tensile strength, and high tension modulus. In order to make full use of such characteristics, a fiber composite twisted cable having carbon fibers and thermosetting resin as a matrix combined to each other is known. 
     The fiber composite twisted cable is manufactured generally by forming strands by twisting bundles of carbon fibers impregnated with thermosetting resin, twisting a plurality of such strands, and then curing the thermosetting resin by heat treatment. 
     However, there is a problem such that air or residual solvent contained in thermosetting resin remains in the interior of a cable as gaps between a process of impregnating with the thermosetting resin and a process of forming a cable by twisting the plurality of strands, whereby mechanical characteristics such as the tensile strength per cross-sectional area of the cable, which is important characteristics as the fiber composite twisted cable is lowered. 
     Accordingly, in JP-A-2-127583, a fiber composite twisted cable formed by winding a fiber yarn on an outer periphery of a strand impregnated with thermosetting resin at an angle close to a right angle with respect to the axial direction of the strand in high density, then twisting a plurality of the strands, and then curing the thermosetting resin by heat treatment is proposed. 
     According to the related art, the fiber bundles are prevented from being unlaid by winding the fiber yarn, and an effect of expelling the air or the residual solvent contained in the interior of the cable is expected by a winding pressure of the fiber yarn. However, when twisting the plurality of strands impregnated with the thermosetting resin, liquid-state thermosetting resin in an uncured state is squeezed out from between the wound fiber yarns, so that the resins from adjacent side strands moisten with respect to each other, and flows into a gap between a core strand and the side strands and stays therein. 
     Therefore, when the thermosetting resin is cured in a last process, the adjacent strands are adhered and integrated with each other (the core strand and the side strands, and the side strands and the side strands), so that the entire cable becomes cured like a hard rod. 
     Therefore, bending rigidity of the fiber composite twisted cables in the related art is very high and, consequently, flexibility that the cable should have under normal circumstances by having a twisted wire structure is impaired, and hence a large reel provided with a large-diameter winding barrel is required. 
     Consequently, when applying the fiber composite twisted cable to a reinforcing member for an overhead transmission line and performing a wiring work in a mountain range for example, problems in transport such that a large vehicle for loading the large reel is required and, road works for moving the large vehicle in turn are required are inevitable. 
     Furthermore, when winding the fiber composite twisted cable on the reel, partial separation of the thermosetting resin which bonds the strands with respect to each other occurs by bending, so that bonded portions and separated portions exist together between the adjacent strands in the longitudinal direction of the cable. Consequently, there arises a problem such that bending occurs when the cable is withdrawn from the reel when using the cable and hence linearity of the cable is impaired. 
     SUMMARY OF THE INVENTION 
     In order to solve the above-described problems as described above, the fiber composite twisted table in the related art is improved, and it is an object of the invention to provide a fiber composite twisted cable having preferable flexibility and being superior in transportability and workability suitable for being used as a reinforcing member for a high-voltage transmission line or a tensile strength reinforcing member for concrete structures such as a bridge girder. 
     In order to achieve the above described object, a fiber composite twisted cable according to an embodiment of the invention is a cable having 1×n structure which is formed by impregnating bundles of carbon fibers with thermosetting resin, then twisting a plurality of strands each formed by covering an outer periphery of the bundle with a fiber, and then curing the thermosetting resin by heat treatment, and is characterized in that a core strand and side strands surrounding the same, which constitute the 1×n structure, are in contact with each other separately and independently without being bonded to each other so as to allow the respective strands to perform independent behaviors when the cable is bent at a right angle with respect to the longitudinal direction. 
     With the fiber composite twisted cable according to the invention, the respective strands which constitute the cable are separately and independently in contact with each other without being bonded to each other, and minute gaps for allowing the independent behaviors when the cable is bent in the direction at a right angle with respect to the longitudinal direction thereof are formed between the core strand and the side strands surrounding the same. Therefore, a constraining force is suitably alleviated by a slipping effect between the adjacent strands, whereby the flexibility required for the cable is improved. 
     Since deformation of the strands due to a bending stress applied to the cable is facilitated by the gaps surrounded by the side strands and the core strand secured therein, the flexibility is further improved. 
     Therefore, according to the embodiment of the invention, since the flexibility of the cable is improved, winding of the cable around the reel, which is inevitable when manufacturing a long cable or transporting the cable as a product, can be performed without problem, and the barrel diameter of the reel can also be reduced. 
     Therefore, when it is used as the reinforcing member for the high-voltage transmission line or the tensile strength reinforcing member for the concrete structure such as a bridge girder, transport of the cable to the mountain range or the mountain area is facilitated, and a transport cost can be reduced. 
     Since the cable can be wound around the reel without problem, generation of abnormal residual stress on the cable is avoided, and formation of curl is avoided even when the cable is withdrawn from the reel when using the same. The cable withdrawn from the reel is easy to handle, allows measurement of the cable length with high degree of accuracy on site, and allows easy terminal process. Therefore, the workability is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view showing a first embodiment of a fiber composite twisted cable according to the invention; 
         FIG. 1B  is a vertical cross-sectional front view of the first embodiment; 
         FIG. 1C  is a partial enlarged view of  FIG. 1B ; 
         FIG. 2A  is a perspective view showing a state in which the fiber composite twisted cable according to the first embodiment is about to be put asunder; 
         FIG. 2B  is a perspective view of the fiber composite twisted cable shown in  FIG. 2A  after having put asunder; 
         FIG. 3  is an explanatory drawing showing a process of manufacturing a prepreg by impregnating a multifilament formed of carbon fibers with thermosetting resin; 
         FIG. 4  is an explanatory drawing showing a process of manufacturing a covered composite strand; 
         FIG. 5  is an explanatory drawing showing a process of manufacturing a composite twisted cable in a semi-cured or uncured state by twisting the covered composite strands; 
         FIG. 6  is an explanatory drawing showing a heat treatment process; 
         FIG. 7A  is a perspective view showing a fiber composite twisted cable after having finished the heat treatment; 
         FIG. 7B  is a cross-sectional view of the fiber composite twisted cable after having finished the heat treatment; 
         FIG. 7C  is a partial enlarged view of  FIG. 7B ; 
         FIG. 8A  is a side view showing an apparatus and a process of separating the strands of the fiber composite twisted cable; 
         FIG. 8B  is a cross-sectional view taken along the line X-X in  FIG. 8A ; 
         FIG. 9A  is a perspective view showing a second embodiment of a fiber composite twisted cable according to the invention; 
         FIG. 9B  is a cross-sectional view showing a state before strand separation according to the second embodiment; 
         FIG. 10A  is a perspective view showing a third embodiment of a fiber composite twisted cable according to the invention; 
         FIG. 10B  is a cross-sectional view showing a state before strand separation according to the third embodiment; 
         FIG. 11A  is a drawing of a state in which power cables are strung showing an example in which the fiber composite twisted cable according to the embodiment of the invention is applied to a reinforcing member of the a high-voltage transmission line; 
         FIG. 11B  is a partially cut-out side view of the power cable shown in  FIG. 11A ; 
         FIG. 11C  is a cross-sectional view of the power cable shown in  FIG. 11B ; 
         FIG. 12A  is a perspective view of a bottom of a bridge showing an example in which the fiber composite twisted cables according to the embodiment of the invention are applied to tensile strength reinforcing members of a concrete bridge girder; and 
         FIG. 12B  is a bottom view of the bridge girder in a tensed state. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the attached drawings, an embodiment of the present invention will be described. 
       FIG. 1A  to  FIG. 2B  show a fiber composite twisted cable having 1×7 structure according to an embodiment of the invention. Reference numeral  1  designates an entire fiber composite twisted cable (hereinafter, referred to simply as “cable”), having a diameter of 12 mm, for example. Reference numerals  21 ,  22  are strands which constitute the cable  1 . The cable  1  includes seven strands having the same thickness. Six side strands  22  are arranged around a single core strand  21 , and these strands are twisted together. 
     The core strand  21  and the side strands  22  are formed by binding or twisting a plurality of prepregs  2 ′, which are formed by impregnating respective bundles of PAN (polyacrylonitrile) carbon fibers  2  with thermosetting resin  3  as shown in  FIG. 1C . Also, the outer periphery of the each strand is covered with a fiber yarn  4  wound therearound at an angle close to a right angle with respect to the axial direction of the strand in the high density. The “yarn” here is a concept including a tape. 
     The core strand  21  and the six side strands  22  are covered with the fibers, and are twisted with the thermosetting resin contained therein uncured and hence are formed into the uncured fiber composite twisted cable. Then, the uncured fiber composite twisted cable is subjected to heat treatment so that the thermosetting resin is cured. 
     However, in the embodiment of the invention, the adjacent side strands  22  and  22  are not bonded to each other, and the side strands  22  and the core strand  21  are not bonded to each other, that is, the respective strands are separated and independent and are only in contact with each other in the longitudinal direction. 
     Therefore, five gaps  5  in substantially a triangle shape, where the thermosetting resin is not present, are formed in a portion surrounded by the core strand  21  and the two side strands  22  and  22  in the embodiment as shown in  FIG. 1B , and the gaps  5  function as spaces for allowing independent behaviors of the strands when the cable is bent in the direction at a right angle with respect to the longitudinal direction. 
       FIGS. 2A and 2B  show the fiber composite twisted cable being put asunder. The single core strand  21  at the center and the six side strands  22  positioned therearound exist separately and independently respectively at a regular helical pitch. The separate and independent relationship between the core strand  21  an the side strands  22  is realized by performing a separation process which forcedly releases a bonded state of the respective strands after the heat treatment, that is, after having cured the thermosetting resin. 
     More specifically, in a manufacturing process, the core strand  21  and the six side strands  22  are twisted in the state in which the thermosetting resin contained therein is uncured or semi-cured. The thermosetting resin is extruded out from between the fiber yarns  4  on the outer peripheries of the respective strands by a pressure applied by this twisting action, and wets the adjacent side strands  22  with respect to each other. It also wets the periphery of the core strand  21 , so that the gaps around the side strands  22  and the core strand  21  are filled with the thermosetting resin. In this state, heat is applied and the thermosetting resin is cured, so that the adjacent side strands  22  and  22  are integrally bonded to each other and the side strands  22  and  22  and the core strand  21  are also bonded to each other. 
     Normally, the fiber composite twisted cable is considered to be a finished product in the state described above. However, according to the embodiment of the invention, the integrally bonded side strands  22  and  22 , and the side strands  22  and  22  and the core strand  21  are separated after the heat treatment into independent individual strands and, in this state, these strands are twisted again into the original state. The separating process is performed after the thermosetting resin is cured and stabilized. Therefore, the adjacent side strands  22  and  22  and the core strand  21  are never bonded to each other again. 
     Since the core strand  21  and the side strands  22  are separated and independent, when a bending stress is applied to the cable  1 , the side strands  22  can be moved in their own about the core strand  21 . Therefore, bending rigidity is smaller than that of a bar (rod) having the same diameter, so that higher flexibility is resulted. 
     Since the substantially triangle gap  5  per unit, which is surrounded by the core strand  21  and the two side strands  22  and  22  allow the side strands  22  to run off on the tensed side and the compressed side when being bent. Therefore, the cable  1  can easily be bent and the residual stress is also alleviated. 
     Subsequently, the manufacturing process of the fiber composite twisted cable  1  according to an embodiment of the invention will be described in detail. 
       FIG. 3  shows a process for obtaining the strand. A multifilament  30  including 12000 carbon fibers having a diameter of 7 μm, for example, and being aligned in parallel are wound around a reel  31 . The multifilament  30  is withdrawn from the reel  31 , is guided to a resin bath  35  via a guide roll  32 , and is allowed to submerge through the thermosetting resin  3 , for example, modified epoxy resin, stored therein, and the multifilament  30  is impregnated with the modified epoxy resin. 
     The multifilament  30  impregnated with the modified epoxy resin is introduced into a dice  33 , and excessive modified epoxy resin is pressed and removed, and is formed into a circular shape in cross-section. Then, the multifilament  30  is passed through a drying furnace  36  to semi-cure the thermosetting resin to form a prepreg (element wire)  38 , which is wound around a reel  39 . The prepreg may be kept in uncured state by omitting or stopping operation of the drying furnace  36 . 
     Subsequently, a number of, for example, fifteen prepregs  38  manufactured in the previous process, not shown, are bundled and twisted at a large pitch, for example, 90 mm, so that a composite element strand is obtained. In this process, for example, fifteen reels  39  having the prepreg  38  wound therearound are arranged on a stand, the fifteen prepregs are withdrawn and bundled into the composite element strand and are twisted by turning the reel in the direction at a right angle with respect to a movement path while winding the same together on a reel. 
     The modified epoxy resin is used when the heat resistance on the order of 130° is required. When the heat resistance as high as 240° is required, Bismaleimide resin is used. 
       FIG. 4  shows a formation of the strand and a covering process, in which reference sign b designates a covering device. A reel  40  having a composite element strand  381  manufactured in the previous process wound therearound is mounted on a supporting shaft  401  of the covering device b. 
     The covering device b is provided with a winding machine  45  around the movement path of the composite element strand, and the fiber yarn  4  is wound around the winding machine  45 . Multifilament yarn formed of multipurpose fiber such as polyester fiber is suitable as the fiber yarn and, for example, that having 8 yarns of 1000 denier is exemplified. 
     The composite element strand  381  is wound by a strand reel  49  via a guide roll  42 , and the winding machine  45  is turned around the composite element strand  381  in the course of movement to wind the fiber yarn  4  on an outer periphery of the composite element strand  381  to cover the outer periphery at an angle close to a right angle with respect to the axial direction, for example, at 60 to 85 degrees in the high density. Consequently, a covered composite strand  50  is manufactured. 
     The purpose for covering the periphery of the strand with the fiber is to bundle the composite element strand  381  and prevent the same from being deformed or unlaid at the time of twisting. Another purpose is to discharge and remove the excessive thermosetting resin or solvent which the strands are impregnated with, or air bubbles which may cause the strength of the cable to be lowered or the like by a winding pressure. 
     Subsequently, the seven strand reels on which the covered composite strands  50  are wound are mounted on a twisting device c shown in  FIG. 5 . 
     The twisting device c includes one strand reel  491  on which a strand which becomes the core strand is wound, and six strand reels  492  on which strands which become the side strands arranged therearound. The six strand reels  492  for the side strands are rotated around the single composite strand  50  which becomes the core strand, the six covered composite strands  50 ′ which become the side strands are twisted and are passed through a voice  51  while being pulled by a capstan  52 , so that the thermosetting resin is wound around a reel  59  as a composite twisted cable  60  in the state in which the thermosetting resin is semi-cured or uncured. 
     Subsequently, the reel  59  on which the uncured composite twisted cable  60  is wound is arranged in a heat treatment device d shown in  FIG. 6 , and the uncured composite twisted cable  60  is passed through a heater  65  under the conditions of, for example, 130° C. and 90 minutes, the semi-cured or uncured thermosetting resin is completely cured, and a cured composite twisted cable  90  is wound around a reel  69 . 
     A semi-cured or uncured thermosetting resin  300  contained in the composite strand of the cured composite twisted cable  90  is exuded from the gaps between the fiber yarns in the initial stage of heating. The respective gaps surrounded by a core strand  91  and side strands  92 ,  92  is filled with the exuded thermosetting resin  300  and the thermosetting resin  300  filled in the respective gaps is cured in the latter half of the heating period. Therefore, as shown in  FIG. 7A  to  FIG. 7C , the core strand  91  and the side strands  92  are integrally bonded. Since the troughs between the adjacent side strands  92 ,  92  are also filled with the thermosetting resin  300 , the side strands  92 ,  92  are also bonded to each other. 
     The form as described above is unavoidable in the fiber composite twisted cable in the related art. The inventors thought of applying the heat treatment on the composite strands  50 ,  50 ′ manufactured in the process shown in  FIG. 4 , forming the strands whose thermosetting resin contained therein is cured, and twisting these hard covered strands into a cable as a measure for improving the flexibility. However, since the hard covered strands are already in the state of hard rods, it is very difficult to bundle seven such hard strands and twist the same into the helical shape. In addition, since the thermosetting resin in the strands is separated during twisting and hence the function as the matrix is impaired, it is not suitable. 
     Accordingly, in the invention, the core strand  91  and the side strands  92 , which are bonded and cured with the thermosetting resin exuded into the gaps surrounded by the core strand  91  and the side strands  92 ,  92  are separated (unstuck) from each other using specific means and process. The bonding between the side strands  92  is also separated (unstuck) from each other. 
       FIG. 8A  and  FIG. 8B  show the process and the device therefor. A strand separating device e includes a rotatable separation plate  70 , and a separation voice  75  and the binding voice  76  are positioned on the downstream side and the upstream side of the separation plate  70 , respectively. The separation plate  70  is formed of a circular metallic plate and includes a core strand insertion hole  73  for insertion of the core strand  91  of the cured composite twisted cable  90  at the center thereof and a plurality of side strand insertion holes  74  arranged radially from the core strand insertion hole  73  apart from each other uniformly. In this example, there are provided the six side strand insertion holes  74 . 
     The separation of the core strand  91  and the side strands  92  are performed as follows. In other words, the cured composite twisted cable  90  wound around the reel  69  is inserted through the separation voice  75 , a terminal end of the inserted cured composite twisted cable  90  is unlaid into individual strands. The core strand  91  is inserted through the core strand insertion hole  73  of the separation plate  70 , and the six side strands  92  are inserted respectively through the side strand insertion holes  74 . 
     Then, the strands  91  and  92  passed through the separation plate  70  are introduced into the binding voice  76 , and are guided to a reel  80  via a capstan  79 . At this time, the separation plate  70  is rotated in the direction opposite from the direction of twisting of the cured composite twisted cable  90  in conjunction with a speed of pulling out the cured composite twisted cable  90 . 
     With this process, the core strand  91  and the side strands  92  of the cured composite twisted cable  90  are separated and the side strands are separated from each other, and hence the bonded state is released. Therefore, the unstuck independent strands are restored to “1×7” twisted relationship in the binding voice  76 , and hence is withdrawn as the fiber composite twisted cable  1  according to the embodiment of the invention in  FIG. 1  and is wound around the reel  80 . 
     The fiber composite twisted cable  1  is improved in flexibility because the gaps, which allow the independent behaviors of the respective strands  21 ,  22  when the cable is bent, are formed between the core strand  21  and the side strands  22  surrounding the same, which constitute the cable, as shown in  FIG. 1  and  FIG. 2 , so that the reel  80  may be downsized in diameter of the barrel and the flange in comparison with the reel for winding the cured fiber composite twisted cable  90  in the related art. Therefore, the style of packaging is downsized and the weight is reduced, so that easy transport is achieved. 
     Referring now to the attached drawings, a second embodiment of the invention will be described. 
       FIG. 9A  shows a fiber composite twisted cable  100  having a structure of 1×19 including nineteen strands, and having a diameter of 18 mm according to the second embodiment of the invention. The composite twisted cable  100  is configured as described in the first embodiment, and the strands are separated and independent without being bonded to each other so that gaps for allowing independent behaviors of the respective strands when the cable is bent are formed between a core strand and side strands surrounding the same. 
     The composite twisted cable  100  includes a single core strand  111  and six first layer strands  112  twisted so as to surround the core strand  111 , and also includes twelve second layer strands  113  twisted on an outer periphery thereof. 
     The respective strands  111 ,  112  and  113  have a configuration including a plurality of twisted prepregs, which are formed of bundles of PAN carbon fiber impregnated with thermosetting resin as in the first embodiment, and outer peripheries of the strands are covered with a fiber yarn  400  wound therearound at an angle close to a right angle with respect to the axial direction of the strand in the high density. 
     Reference numerals  500  designate five substantially triangle shaped gaps surrounded by the core strand  111  and the first layer strands  112  and  112 . By the existence of the gaps, the first layer strands  112  and  112 , and the core strand  111  are separated and independent and are only in contact with each other in the longitudinal direction without being bonded to each other. The adjacent first layer strands  112  and  112  are also separated and independent in the longitudinal direction without being bonded to each other. 
     Reference numerals  501  designate six substantially crescent-shaped gaps surrounded by the first layer strands  112  and the second layer strands  113 , and the first layer strands  112  and the second layer strands  113  are separated and independent and are only in contact with each other in the longitudinal direction without being bonded to each other. The adjacent second layer strands  113  and  113  are also separated and independent and are only in contact with each other in the longitudinal direction without being bonded to each other. 
     The gaps  500 ,  501  function as spaces which allow independent behaviors of the strands when the cable is bent in the direction at a right angle with respect to the longitudinal direction of the cable. 
     The manufacturing process will be described, the core strand  111 , the first layer strands  112 , and the second layer strands  113  after having covered with the fiber yarns are twisted into an uncured fiber composite twisted cable in a state in which the thermosetting resin contained therein is not cured, and the thermosetting resin is cured by applying the heat treatment on the uncured fiber composite twisted cable, whereby a semi-finished product as shown in  FIG. 9B  is obtained. At this time, as in the case of the first embodiment, the core strand  111  and the first layer strands  112  are integrally bonded with the exuded liquid-state thermosetting resin  300 , and the first layer strands  112  and the second layer strands  113  surrounding the same are integrally bonded with the exuded liquid-state thermosetting resin  300 . 
     In order to obtain the above-described composite twisted cable  100 , as in the case of the first embodiment, it is forcedly unstuck using a separating device to release the bonded state. Other points are the same as described in the first embodiment. 
     Referring now to the attached drawings, a third embodiment of the invention will be described. 
       FIG. 10A  shows a fiber composite twisted cable  200  having a structure of 1×37 including thirty seven strands, and having a diameter of 28 mm according to a third embodiment of the invention. 
     The cable  200  includes a single core strand  211  and six first layer strands  212  twisted so as to surround the core strand  211 , includes twelve second layer strands  213  twisted on an outer periphery thereof, and further includes eighteen third layer strands  214  twisted on the outer periphery thereof. 
     Reference numerals  500  designate five substantially triangle shaped gaps surrounded by the core strand  211  and the first layer strands  212  and  212 . By the existence of the gaps, the first layer strands  212  and  212 , and the core strand  211  are separated and independent and are only in contact with each other in the longitudinal direction without being bonded to each other. 
     Reference numerals  501  designate six substantially crescent-shaped gaps surrounded by the first layer strands  212  and the second layer strands  213 , and the first layer strands  212  and the second layer strands  213  are separated and independent and are only in contact with each other in the longitudinal direction without being bonded to each other. The adjacent second layer strands  213  and  213  are also separated and independent without being bonded to each other and are in contact with each other in the longitudinal direction. 
     Reference numerals  502  designate a number of diamond-shaped gaps surrounded by the second layer strands  213  and the third layer strands  214 . With these gaps, the second layer strands  213  and the third layer strands  214  are separated and independent and are in contact with each other in the longitudinal direction without being bonded to each other. The adjacent third layer strands  214  and  214  are also separated and independent without being bonded to each other and are in contact with each other in the longitudinal direction. The gaps  500 ,  501  and  502  function as spaces which allow independent behaviors of the strands when the cable is bent in the direction at a right angle with respect to the longitudinal direction of the cable. 
     The core strand  211 , the first layer strands  212 , the second layer strands  213  and the third strands  214  after having covered with the fiber yarns are twisted into an uncured fiber composite twisted cable in a state in which the thermosetting resin contained therein is not cured, and the thermosetting resin is cured by applying the heat treatment on the uncured fiber composite twisted cable, whereby a semi-finished product as shown in  FIG. 10B  is obtained. At this time, as in the case of the first embodiment, the core strand  211  and the first layer strands  212  are integrally bonded with the exuded liquid-state thermosetting resin  300 , and the first layer strands  212  and the second layer strands  213  surrounding the same, and the second layer strands  213  and the third layer strands  214  surrounding the same are integrally bonded with the exuded liquid-state thermosetting resin  300 . 
     In order to obtain the above-described composite twisted cable  200 , as in the first embodiment described above, it is forcedly unstuck using the separating device to release the bonded state of the strands with respect to each other. Other points are the same as described in first embodiment. 
       FIGS. 11A ,  11 B and  11 C show examples in which the fiber composite twisted cable according to the embodiment of the invention is used as a reinforcing member for an overhead transmission line. High-voltage transmission lines B extended between steel towers A in  FIG. 11A  have a structure as shown in  FIG. 11B  and  FIG. 11C . In other words, the fiber composite twisted cable  1  in the first embodiment is used as a core member, and aluminum lines or heat-proof aluminum alloy wires  900  are arranged in two layers and twisted on the periphery thereof. 
       FIGS. 12A and 12B  show examples in which the fiber composite twisted cable according to the embodiment of the invention is applied to a reinforcing member of a concrete structure. In order to reinforce a bridge girder C, the fiber composite twisted cables  1 ,  100 , or  200  according to any one of the first to the third embodiments are extended between the bridge girders C provided at both ends in the longitudinal direction, and a tonicity is applied thereto using a fixing member. 
     The fiber composite twisted cable according to the embodiments of the invention is applied also to cables for a suspension bridge or ground anchors.

Technology Classification (CPC): 3