JP4805010B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to an optical fiber cable, and more particularly to an optical fiber cable having a structure in which an optical fiber core wire is accommodated in a groove of a slot and the outer periphery thereof is covered with a press-wound tape and a sheath.

  As shown in FIG. 10, for example, the slot type optical fiber cable includes a slot 103 having a plurality of grooves 102 extending in the longitudinal direction on the outer periphery, an optical fiber core wire 101 accommodated in the groove 102, an optical fiber, A presser winding tape 104 wound on the fiber core wire 101 and the slot 103 and a sheath 105 covering the slot 103 from above the presser winding tape 104 are provided. The optical fiber cable having such a structure is described in, for example, Patent Document 1 below.

  The presser winding tape 104 covers the entire surface of the slot 103 in order to prevent the optical fiber core wire 101 from jumping out of the groove 102 and not to transmit heat to the optical fiber core wire 103 when the sheath 105 is pushed out and covered. It has a configuration.

  Such a slot type optical fiber cable includes a structure in which the groove 102 is spiraled in the same direction along the length direction of the slot 103, an SZ twisted structure in which the groove 102 is alternately twisted, and the like, and is wound around the outer periphery of the slot. The presser winding tape 104 to be rotated may be wound not only in a single layer but also in a plurality of layers.

  For example, as shown in FIG. 11, in an optical fiber cable using an SZ twist slot 106, a lower presser made of a string or a narrow tape is used to prevent the optical fiber core wire 101 housed in the groove 102 from jumping out. The winding 107 is spirally wound around the outer periphery of the SZ twist slot 106, and the upper presser winding tape 104 made of a wide tape is spirally wound thereon so as to overlap little by little. The whole 104 is covered with a sheath 105.

  Further, as shown in FIG. 12, there is an optical fiber cable having a structure in which an upper presser winding tape 104 is wound vertically on the outer periphery of an SZ twist slot 106 and a lower presser roll 107. The vertical attachment is a structure in which both sides of the presser winding tape 104 are wound substantially in a straight line along the longitudinal direction of the slot 103 instead of being wound spirally.

Furthermore, as shown in FIG. 12, the vertically attached presser winding tape 104 described in Patent Document 2 has a structure that is covered with a sheath 105 in a state where a presser thread 108 is roughly wound around the outer periphery thereof. Further, the press-fitting tape 104 with vertical attachment described in Patent Document 3 has a structure in which the overlapped both side portions are bonded with a heat-fusible resin or the like without using the press-fitting yarn 108.
JP 2002-243999 A JP 2000-98200 A JP 2004-12914 A

  By the way, the above-described conventional optical fiber cable has the following problems from the viewpoint of disassembly.

  The status of dismantling the optical fiber cable includes removing the sheath and presser tape when removing the optical fiber cable and removing the optical fiber core wire during construction of the optical transmission line, or collecting the optical fiber from the optical transmission line. In some cases, components are separated to recycle cables.

  When the sheath is removed from the optical fiber cable at the time of construction of the optical transmission line branching work, a presser winding tape appears below the sheath. In order to remove the wide presser tape wound spirally, there is only a method of cutting a part of the tape and unwinding it in the direction opposite to that at the time of manufacture.

  In addition, when removing the presser winding thread wound on the vertical presser foot winding tape described in Patent Document 2, there is also a method of cutting and pulling the middle part of the thread and removing it from the slot. If there is a wrinkle in the vertical presser winding tape, the portion becomes a resistance, and when the presser thread is pulled, over tension is applied, which may damage the optical fiber core wire in the groove.

  In order to avoid this, after all, there is only a method of unwinding and removing the presser winding thread in the direction opposite to that at the time of manufacture, and these operations are very heavy and take time. In particular, in the post-intermediate branching work of taking out the optical fiber from the middle of the installed optical fiber cable, the work such as dismantling must be performed in a narrow space, and the load is further increased.

  On the other hand, in the case of disassembly separation work, there is no problem even if the optical fiber core wire is damaged, so when removing the sheath, a blade such as a cutter is inserted deeply into the slot and cut in the longitudinal direction to remove the sheath. A method of cutting both presser foot windings at the same time can be employed.

  However, when the presser thread wound on the presser tape is cut in the longitudinal direction, the presser thread is divided into a number of short threads, some of which are in the cylindrical sheath made of different materials and in the slot grooves. It becomes a situation that is difficult to separate.

  On the other hand, as described in Patent Document 3, if a structure in which both side portions of the press-fitting tape with vertical attachment are bonded to the entire length with a heat-fusible resin or the like is provided, a press-winding thread as in Patent Document 2 is provided. There is no need, and it is not necessary to remove the presser thread during recycling.

  When removing the vertical presser tape with both sides bonded by heat fusion, etc., it cannot be unwound in the opposite direction of winding as with a wound presser tape. However, in the dismantling work for recycling, it can be cut out with a cutter together with the sheath.

  However, when a part of the optical fiber core is taken out for branching the optical transmission line, there is a possibility that the teeth of the cutter are put too deep and the optical fiber core is damaged. Therefore, there is no other way to remove the optical fiber core than cutting the vertical presser tape with a cutter. In this case, insert the teeth of the cutter carefully with a cutter from the viewpoint of protecting the optical fiber core. It is necessary to work, and workability is reduced.

  An object of the present invention is to provide an optical fiber cable capable of easily disassembling a vertical presser tape wound around a slot.

In order to solve the above-described problems , the present invention provides a slot having a groove on the outer peripheral surface, an optical fiber housed in the groove, a vertical presser tape that covers the slot and the optical fiber, A sheath for covering the presser winding tape, wherein one side portion of the presser winding tape has an upper layer and a lower layer via an adhesive layer on the other side portion of the vertical seam of the presser winding tape. and with close contact with it by adhesion F _1, the adhesion layer is in close contact with the adhesion force F ₂ at the protruding from longitudinal accompanied combined in the upper layer in the region on the inner surface of the sheath, and the adhesion force F ₁ relationship adhesion F ₂ is a fiber cable, characterized in F ₁ <F ₂ der Rukoto.

In the above-described configuration, the adhesion layer protrudes from the upper layer to the lower layer in the longitudinal seam, and the protruded region has an adhesion force F on the inner surface of the sheath. ₂ It may be in close contact.

In the above-described configuration, the adhesion layer is in the form of a film, and a portion of the vertical joint that protrudes from the upper layer is folded back onto the upper layer, and the folded area is adhered to the inner surface of the sheath. it may be in close contact with a force F _2.

In the above configuration, the adhesion layer may be made of the same material system as the sheath .

Furthermore, in the above-described configuration, a mark may be attached to the outer peripheral surface of the sheath on the opposite side of the vertical seam of the presser tape .

According to the optical fiber cable according to the onset bright, comprising a presser winding tape wound in the longitudinal appended to the slot periphery with a groove for accommodating the optical fiber, and a sheath covering the slot from above the presser winding tape, further, One side portion of the presser winding tape is in close contact with the other side portion at a vertically attached seam and also in close contact with the sheath.

  By applying an adhesive force to the vertical seam portion of the presser winding tape, it is possible to prevent peeling of the vertical seam when the sheath is formed. Thereby, it is not necessary to wind a tape or a string around the outer periphery of the vertically attached presser winding tape as in Patent Document 2.

  In addition, if the adhesive force between the upper layer of the presser wound tape and the sheath at the vertical seam is greater than the adhesive force within the seam, the presser that appears by making a cut in a part of the sheath Of the wound tape, it is easy to open the bottom seam by opening the lower layer while keeping the upper layer in the seam of the vertical joint in close contact with the sheath, and it is easy to take out the optical fiber from there Become.

  Adhesion between the upper layer of the vertical seam and the sheath is performed through the adhesion layer.

    Only the presser tape with vertical attachment is exposed after opening the sheath using a cutter. Unlike Patent Document 3, the presser tape is peeled off by a human hand to damage the optical fiber. It can be taken out without. Therefore, it is possible to significantly reduce the work time for removing the presser foot during construction of the optical transmission line or when disassembling and separating the recycle, and the work efficiency can be improved.

  In this case, in the state where a cut is made in the sheath, a part of the presser tape is exposed, and the upper layer, which is the other side of the seam, and the sheath are substantially fixed via the adhesion layer, the presser tape When the slot and presser tape are slightly rotated in the opening direction, the lower layer, which is one side of the seam, is peeled off from the upper layer, and the longitudinal seam can be easily released.

In this case, the adhesion layer causes the upper layer and the lower layer to adhere to each other with the adhesion force F ₁ and protrudes from the upper layer to the lower layer of the vertical joint, and the protruding region is an inner surface of the sheath. close contact with the adhesion force F ₂ in the relationship of the adhesive force F ₂ and the adhesion F ₁ with F ₁ <F _2, easily vertically served alignment of the upper layer and the sheath substantially fixed state The upper and lower layers of the eye can be opened.

Further, the adhesive layer is formed into a film shape, and the portion of the vertical joint that protrudes from the upper layer is folded back onto the upper layer, and the folded region is adhered to the inner surface of the sheath. ₂ By adhering to the upper layer, the upper layer is sandwiched between the adhesion layers, and it is difficult to peel off the upper layer from the sheath, so that the seam can be easily opened as a fixed portion.

In the configuration described above, the adhesive layer can be strongly adhered to the sheath by being composed of the same material system as that of the sheath, and may be separated as it is.

In addition, by marking the outer peripheral surface of the sheath on the opposite side of the vertical seam of the press-wound tape, the position where the cut is made by the cutter becomes clear during disassembly separation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1A is a side view showing a state before the sheath is formed in the optical fiber cable according to the first embodiment of the present invention, and FIG. 1B is a side view showing the state after the sheath is formed. FIG. 2 is a cross-sectional view of the optical fiber cable according to the first embodiment of the present invention.

  In FIG. 1A, on the SZ twist slot 3 having an outer diameter of 9.0 mm formed by alternately twisting the grooves 2 for accommodating the optical fibers 1, the width is 40 mm and the thickness is made of a nonwoven fabric bonded with PET. A presser winding tape 4 having a thickness of 0.2 mm is wound vertically. In addition, although the optical fiber 1 in Fig.1 (a) is an optical fiber tape, it is not restricted to this.

  Both side portions of the vertically attached presser winding tape 4 are superposed on each other along the substantially straight line in the longitudinal direction on the slot 3, thereby forming a seam 5.

  A first adhesion region is provided between the lower layer 4a, which is one side portion of the presser winding tape 4, and the upper layer 4b, which is the other side portion, in the seam 5, where an adhesive film 6 is provided. The lower layer 4a and the upper layer 4b are in close contact with each other.

  The adhesive film 6 has a thickness of 0.05 mm and a width of 20 mm, and is also attached to a range of the lower layer 4a that reaches the second adhesion region that protrudes from the upper layer 4b. The upper surface of the adhesive film 6 sticking out and sticking out to the second adhesion region is stuck to the inner surface of the sheath 7 by covering the presser winding tape 4 attached vertically with the cylindrical sheath 7. The adhesive film 6 has, for example, a polyethylene film or a structure based on this.

  As shown in FIGS. 1B and 2, the adhesive force of the adhesive film 6 is lower than the seam 5 of the presser tape 4 until the presser tape 4 is covered with the sheath 7. The strength is such that the layer 4a and the upper layer 4b are not opened, and the strength is such that the upper layer 4b and the lower layer 4a can be easily opened by a human hand after close contact.

Further, the adhesive film 6 is configured such that the adhesion force F ₂ with the sheath 7 is stronger than the adhesion force F ₁ with the lower layer 4 a of the presser winding tape 4.

  The sheath 7 shown in FIGS. 1B and 2 is made of polyethylene having a thickness of 2.0 mm formed on the outer periphery of the press-wound tape 4 covering the slot 3 by, for example, an extrusion coating method. The extrusion temperature of the sheath 7 is 190 ° C., for example.

  The optical fiber cable fabrication process is as follows. First, the optical fiber 1 is put in the groove 2, and the both sides of the presser tape 4 are vertically stacked on the slot 3, and are closely adhered between the joints 5. The adhesive film 6 is interposed as a layer, and the adhesive layer protrudes from the lower layer 4a.

  The adhesive film 6 is heated in a state of being inserted into the seam 5 with a heater, so that the adhesiveness of the lower layer 6 a and the upper layer 6 b is maintained at the seam 5. When the sheath 7 is formed, the sheath 7 and the presser winding tape 6 are brought into close contact with each other by heat forming the sheath 7. In this case, by forming the adhesive film 6 from the same polyethylene as the sheath 7, the sheath 7 and the adhesive film 6 are integrated or adhered with high adhesion.

  When performing an operation of taking out a part of the optical fiber from the optical fiber cable having the above-described configuration or separating and disassembling, first, a part of the sheath 7 is cut in the longitudinal direction by a cutter. The position where the cut is made is preferably at a position opposite to the seam 5 of the presser winding tape 4, and a mark may be attached to the outer peripheral surface of the sheath 7 corresponding to the position.

  When the sheath 7 is opened from the notch, the presser tape 4 appears. Therefore, as shown in FIG. 3, when the presser winding tape 4 is turned in a direction opposite to the winding direction of the presser winding tape 4 at the time of making the optical fiber cable, the adhesive film 6 is brought into close contact with the sheath 7. Since the adhesive force with the presser winding tape 4 is smaller than the force, the adhesive film 6 protruding from the seam 5 of the presser tape 4 is peeled off from the lower layer 4 a of the presser tape 4, and the peeling is within the seam 5. Finally, the joint 5 of the presser tape 4 is opened.

  In this case, since the upper layer 4b of the presser winding tape 4 is sandwiched between the adhesive film 6 and the sheath 7, the upper layer 4b is not easily peeled off from the adhesive film 6 due to friction.

  Since the slot 3 appears from the pressed presser tape 4, the optical fiber 1 exposed from the groove 2 of the slot 3 can be easily taken out. Thereby, the effect | action which takes out the optical fiber 1 from an optical fiber cable will be reduced rather than before.

  In the operation of separating and disassembling the optical fiber cable after removing the optical fiber cable from the optical transmission line, the adhesive film 6 has a higher adhesive force to the sheath 7 than the presser winding tape 4, so that the adhesive film 6 and the presser winding tape 4 are adhesive. If a force larger than the adhesion force of the film 6 is applied to the presser tape 4 and pulled out from the sheath 7, the presser tape 4 is separated from the optical fiber cable.

  The sheath 7 and the adhesive film 6 are made of the same material, for example, polyethylene, so that the sheath and the adhesive film 6 are integrated when the sheath is formed. Therefore, the adhesive film 6 from which the presser tape 4 is separated is the sheath film. There is no problem even if the separation work is performed while being adhered to 7, and the separation work becomes easy.

  In addition, you may use the adhesive film 6 comprised based on ethylene-vinyl acetate copolymer resin (EVA) as a contact | adherence layer, and it adheres to both the press-wound tape 4 and the sheath 6 by the heating at the time of sheath formation.

  In this case, since the adhesive force with the polyethylene sheath 6 is larger than the adhesive force with the presser wound tape 4 made of a nonwoven fabric bonded with PET, the presser wound tape is formed by making a cut in the longitudinal direction in the sheath 6. 4 is easy to dismantle and separate.

When using an adhesion layer made of EVA, the adhesion layer is finally peeled off from the sheath 7.
(Second Embodiment)
FIG. 4A is a side view showing a state before the sheath is formed in the optical fiber cable according to the second embodiment of the present invention, and FIG. 4B is a side view showing the state after the sheath is formed. FIG. 5 is a cross-sectional view of an optical fiber cable according to the second embodiment of the present invention. 4 and 5, the same reference numerals as those in FIGS. 1 and 2 denote the same elements.

  In FIG. 4 (a), a press-wound tape 4 made of a nonwoven fabric bonded with PET is wound on the SZ twist slot 3 formed by alternately twisting the grooves 2 for housing the optical fibers 1 in a vertical direction. ing.

  Both side portions of the vertically attached presser winding tape 4 are superposed on each other along the substantially straight line in the longitudinal direction on the slot 3, thereby forming a seam 5.

  A first adhesion region is provided between the lower layer 4a, which is one side portion of the presser winding tape 4, and the upper layer 4b, which is the other side portion, in the seam 5, where an adhesive film 6 is provided. The lower layer 4a and the upper layer 4b are in close contact with each other. Furthermore, a second adhesion region is provided on the upper layer 4 b in the joint 5.

  The adhesive film 6 has a thickness of 0.05 mm and a width of 20 mm. The adhesive film 6 is attached between the lower layer 4a and the upper layer 4b, and the portion protruding from the upper layer 4b is folded back on the upper layer 4b. Is attached to the second contact area.

  The adhesive film 6 sticking out and sticking out to the second adhesion region is attached to the sheath 7 by covering the presser winding tape 4 attached vertically with the sheath 7. The adhesive film 6 has, for example, a polyethylene film or a structure based on this.

  The adhesive force of the adhesive film 6 is such that the lower layer in the seam 5 of the presser tape 4 is processed until the presser tape 4 is covered with the sheath 7 as shown in FIGS. The strength is such that 4a and upper layer 4b do not open, and the upper layer 4a and lower layer 4b can be easily opened by human hands after close contact.

Further, the adhesive film 6 is configured such that the adhesion force F ₂ with the sheath 7 is stronger than the adhesion force F ₁ with the lower layer 4 a surface of the presser winding tape 4.

  The sheath 7 shown in FIGS. 4B and 5 is made of polyethylene having a thickness of 2.0 mm formed on the outer periphery of the presser winding tape 4 covering the slot 3.

  In the process of manufacturing the optical fiber cable, first, in a state where the optical fiber 1 is put in the groove 2, the presser winding tape 4 is wound vertically on the slot 3, and then the adhesive film 6 is formed as an adhesion layer. It is interposed between the seams 5 and folded over the upper layer 4b.

  When the adhesive film 6 is inserted into the seam 5, the adhesive film 6 is folded upward and further heated by a heater to adhere the lower layer 4 a and the upper layer 4 b of the presser tape 4 at the seam 5. Is kept in close contact with the upper surface of the seam 5 of the presser winding tape 4.

  After the slot 3 is covered with the vertical presser tape 4, the sheath 7 made of polyethylene is formed on the outer periphery of the presser tape 4 by, for example, extrusion coating. The extrusion temperature for sheath formation is 190 ° C., for example.

  At this time, the adhesive film 6 exposed on the presser winding tape 4 is in close contact with the sheath 7 by heat for forming the sheath 7. In this case, by forming the adhesive film 6 from the same polyethylene as the sheath 7, the sheath 7 and the adhesive film 6 are integrated or adhered with high adhesion.

  When removing the optical fiber 1 from the optical fiber cable having the above configuration or disassembling, first, a part of the sheath 7 is cut in the longitudinal direction by a cutter. The position where the cut is made is preferably at a position opposite to the seam 5 of the presser winding tape 4, and a mark may be attached to the outer peripheral surface of the sheath 7 corresponding to the position.

  When the sheath 7 is opened from the cut of the sheath 7, the presser winding tape 4 appears there. Therefore, when the presser winding tape 4 is rotated in the direction of opening as shown in FIG. 6, the adhesive film 6 has less adhesive force with the presser winding tape 4 than the adhesive force with the sheath 7. The upper layer 6b and the lower layer 6a of the seam 5 of the winding tape 4 are peeled off.

  In this case, since the upper layer 4 b of the joint 5 is sandwiched between the folded portions of the adhesive film 6, it is difficult to peel off from the sheath 6. Thereby, the joint 5 of the presser winding tape 4 is unwound from the lower layer 4a.

  Since the slot 3 appears from the pressed presser tape 4, the optical fiber 1 exposed from the groove 2 of the slot 3 can be easily taken out. Thereby, the effect | action which takes out the optical fiber 1 from an optical fiber cable will be reduced rather than before.

  Further, in the operation of separating and disassembling the optical fiber cable after removing it from the optical transmission line, the adhesive film 6 has a higher adhesive force with the sheath than the presser wound tape 4, so that the presser wound tape 4 and the adhesive film When a force larger than the adhesion force 6 is applied to the presser tape 4 and pulled out from the sheath 7, the presser tape 4 is peeled off from the adhesive film 6 and separated from the optical fiber cable. In addition, when the sheath 5 and the adhesive film 6 are made of the same material, for example, polyethylene, the adhesive film can be separated while being adhered to the sheath. Absent.

In addition, you may use the adhesive film 6 comprised based on ethylene-vinyl acetate copolymer resin (EVA) as a contact | adherence layer, and the press-wound tape 4 and sheath by heat at the time of sheath formation like 1st Embodiment. 6 is in close contact with both.
(Third embodiment)
FIG. 7 is a side view showing a third embodiment of the present invention. The same reference numerals as those in FIGS. 1 and 2 denote the same elements.

  In the optical fiber cable shown in FIG. 7, the optical fiber 1 is housed in the groove 2 of the SZ twist slot 3 having an outer diameter of 9.0 mm, and the lower presser winding 9 made of a string or a narrow tape is spaced. Alternatively, a structure wound spirally may be employed. This prevents the optical fiber 1 from jumping out of the groove 2.

  The lower presser winding 9 is made of, for example, a nylon string having a breaking strength of 40 to 100 N or a tape made of PET, and the outer periphery of the slot 3 is wound spirally at three equal intervals. Is pushed to the slot 3 side.

  It should be noted that disassembling the lower presser winding 9 wound in a spiral manner is somewhat complicated, but the lower presser winding 9 is such that there is a gap between the lower presser winding 9 and the slot 3. If the contact area between the slot 3 and the slot 3 is reduced, the friction between the lower presser roll 9 and the slot 3 is reduced, and the lower presser roll 9 is moved along the longitudinal direction of the slot 3 and removed. Easy.

  When the lower presser winding 9 is cut and removed, the cutting tool can be used while observing the optical fiber 1 so that the optical fiber 1 is not damaged from the gap between the lower presser windings 9, so that the optical fiber 1 can be damaged. Sex is reduced. In order to effectively use the blade while visually observing, it is preferable that the interval between the lower presser rolls 9 on the slot 3 is 5 mm or more.

In the optical fiber cable shown in FIG. 7, the vertical seam 5 of the press-wound tape 4 and the adhesion layer in the protruding region are shown corresponding to the first embodiment, but as in the second embodiment. The adhesion layer 6 may also be provided in the joint 5 and on the upper layer 4a.
(Other embodiments)
The optical fiber 1 accommodated in the groove 2 provided in the slot 3 is not limited to the optical fiber tape as shown in FIG. 2, but the optical fiber single wire 1a can be accommodated as shown in FIG. Alternatively, as shown in FIG. 8B, a structure in which a plurality of bundled optical fiber single wires 1b are accommodated may be used. Further, as shown in FIG. 9, an S-twisted slot 3a in which a groove 2a for storing an optical fiber is twisted in one direction may be used as a slot for storing an optical fiber tape, an optical fiber single line, or the like.

  In the optical fiber cable shown in FIGS. 8 and 9, the vertical seam 5 of the press-wound tape and the adhesion layer in the protruding area are shown corresponding to the first embodiment, but the second embodiment. As described above, the adhesion layer may be folded back and provided in the joint 5 and on the upper layer 4a.

  The material of the vertically attached presser winding tape 4 is not limited to the non-woven fabric bonded with PET, and may be a general plastic.

  In addition, the adhesion layer between the lower layer 4a and the upper layer 4b at the joint 5 of the presser winding tape 4 and the adhesion layer between the presser tape 4 and the sheath 5 are the same as those in the first and second embodiments. Thus, it may be adhered by one adhesive film, or may be adhered by two separated adhesive films. In this case, you may give different contact | adhesion power to two separated adhesive films.

  Moreover, you may use an adhesive, an adhesive agent, etc. instead of said adhesive film.

FIG. 1 is a side view showing an optical fiber cable according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the optical fiber cable according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a state where the sheath and the presser winding tape are opened when the optical fiber cable according to the first embodiment of the present invention is disassembled. FIG. 4 is a side view showing an optical fiber cable according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view of an optical fiber cable according to the second embodiment of the present invention. FIG. 6 is a cross-sectional view showing a state where the sheath and the presser winding tape are opened when the optical fiber cable according to the second embodiment of the present invention is disassembled. FIG. 7 is a side view showing an optical fiber cable according to the third embodiment of the present invention. FIG. 8 is a cross-sectional view showing another example of the optical fiber housed in the optical fiber cable according to the embodiment of the present invention. FIG. 9 is a side view showing another example of the slots constituting the optical fiber cable according to the embodiment of the present invention. FIG. 10 is a cross-sectional view showing a first example of a conventional optical fiber cable. FIG. 11 is a side view showing a second example of a conventional optical fiber cable. FIG. 12 is a side view showing a third example of a conventional optical fiber cable.

Explanation of symbols

1: optical fiber 2: groove 3: slot 4: presser winding tape 5: joint 6: adhesive film 6
7: Sheath 4a: Lower layer 4b: Upper layer

Claims (5)

A slot having a groove on the outer peripheral surface;
An optical fiber housed in the groove;
A vertical presser tape covering the slot and the optical fiber;
A sheath for covering the presser winding tape,
One side of the presser winding tape, the longitudinal served other side at the joint of the presser winding tape, as well as adhesion in adhesion force F ₁ becomes the upper layer and the lower layer through the adhesive layer The adhesion layer is in close contact with the inner surface of the sheath with an adhesion force F ₂ in a region protruding from the upper layer of the vertical seam, and the relationship between the adhesion force F ₁ and the adhesion force F ₂ is F ₁ <F. optical fiber cable, which is a _2. The adhesion layer protrudes from the upper layer to the lower layer in the vertical joint, and the protruding area is adhered to the inner surface of the sheath. ₂ The optical fiber cable according to claim 1, wherein the optical fiber cable is closely attached. The adhesion layer is in the form of a film, and a portion protruding from the upper layer in the vertical joint seam is folded back on the upper layer, and the folded area is adhered to the inner surface of the sheath. ₂ The optical fiber cable according to claim 1, wherein the optical fiber cable is closely attached. The optical fiber cable according to any one of claims 1 to 3, wherein the adhesion layer is made of the same material system as that of the sheath. The optical fiber cable according to any one of claims 1 to 4, wherein a mark is attached to an outer peripheral surface of the sheath on a side opposite to a vertical seam of the presser winding tape.

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