JP5465613B2 - Optical fiber cable bend preventer - Google Patents

Description

  The present invention relates to an optical fiber cable bend preventer capable of preventing a fiber strand of an optical fiber cable exposed by peeling off an outer coating from being bent with a radius of curvature equal to or less than a minimum bend radius of the fiber strand. About.

  Conventionally, when optical fiber cables cannot be laid under the floor when connecting between communication devices, for example, a wiring rack is attached on the communication device, and the optical fiber cables are laid on the wiring rack. It is common to do. Then, an optical fiber cable is introduced into the communication device from the wiring rack, and the introduced optical fiber cable is connected to an optical terminal device provided in the communication device. At this time, the outer sheath of a predetermined dimension at the end of the optical fiber cable is peeled off to expose the fiber strand. If the fiber strand is not properly fixed, the fiber strand is not When the tension is applied to the fiber, the fiber strand is bent beyond the minimum bend radius, which causes a transmission loss failure.

  Therefore, an optical fiber cable bend preventer is provided for preventing the fiber strand from being bent beyond the minimum bend radius. As an optical fiber cable bending prevention tool, for example, an optical fiber cable provided with an elongated member bent at a curvature radius not smaller than the minimum bending radius of a fiber strand is known (see Patent Document 1).

JP 2002-357552 A

  However, since the conventional optical fiber cable bend prevention tool includes an elongated member bent with a curvature radius not smaller than the minimum bending radius of the fiber strand, the fiber element wired along the elongated member is provided. Although effective in preventing the bending of the wire, there is a problem that it cannot cope with a fiber strand wired in a straight line or a fiber strand wired in a straight line. The same problem as described above also occurs when the fiber strands wired along the elongated member are pulled from a direction different from the bending direction of the elongated member.

  Therefore, in view of the above problems, the present invention provides an optical fiber that can prevent a fiber strand of an optical fiber cable exposed by peeling off an outer coating from being bent with a radius of curvature equal to or less than the minimum bending radius of the fiber strand. It aims at providing the cable bending prevention tool.

In order to solve the above-described problems, the optical fiber cable bending preventer according to the present invention is such that the fiber strand 11 of the optical fiber cable 10 exposed by peeling off the outer coating is equal to or less than the minimum bending radius of the fiber strand 11. In an optical fiber cable bend prevention device that prevents bending at a radius of curvature of the optical fiber cable, one end side disposed to face the tip portion of the fiber strand 11 and the other end facing the outer sheath of the optical fiber cable 10 A straight member 1, 1A, 1B, the one end of which is fixed to the tip of the fiber strand 11, and the other end is fixed to the outer sheath of the optical fiber cable 10. , 1A, 1B, together are configured to deflect a minimum bending radius of curvature greater than the radius of the fiber 11, to bend Tsukishitaga' its deflection, fiber 11 Is along, Jikajo member 1, 1A, is 1B one end of, Jikajo member 1, 1A, and wherein the constructed to deflect than the other end of 1B.

In this case, the straight members 1, 1A, 1B configured to bend with a radius of curvature larger than the minimum bending radius of the fiber strand 11 are bent so as to bend according to the bending of the straight members 1, 1A, 1B. Since the strand 11 is laid, the fiber strand 11 can be wired in either a straight state or a curved state. In addition, the fiber strand 11 is bent according to the bending of the straight members 1, 1 </ b> A, 1 </ b> B regardless of the wiring state being pulled and bent in the other direction. It is not bent beyond the bending radius, and transmission loss failure due to bending of the fiber strand 11 can be prevented. Further, since the straight members 1, 1 </ b> A, 1 </ b> B are configured to bend with a radius of curvature larger than the minimum bending radius of the fiber strand 11, even if the fiber strand 11 is already wired, The straight members 1, 1 </ b> A, 1 </ b> B can be provided according to the state of the fiber strand 11 made. Therefore, excessive bending of the fiber strand 11 in the wired state can be prevented. Further, it is not necessary to perform a curing treatment for preventing the bending of the fiber strand 11 which has been conventionally performed, and wiring work is facilitated.
Further, since one end side of the straight members 1, 1A, 1B is configured to bend more than the other end side of the straight members 1, 1A, 1B, even if a large tensile load is applied to the fiber strand 11, It is possible to prevent the tensile action on the way.
In addition, the bending of the straight members 1, 1A, 1B referred to here includes both the case where the whole is bent in an arc shape and the case where only the tip portion is bent.

  Further, according to the present invention, the linear member 1 includes a flexible linear portion 2 and a guide portion that is disposed along the axial direction of the linear portion 2 and into which the fiber strand 11 is loosely inserted. 30 and 31 may be used.

  In this case, since the fiber strand 11 is loosely inserted into the guide portions 30 and 31 disposed along the axial direction of the linear portion 2, the linear portion is guided while being guided by the guide portions 30 and 31. It will be bent according to the deflection of 2. For this reason, the fiber strand 11 is not bent excessively.

  Further, according to the present invention, the straight member 1A may be configured by a cylindrical body into which the fiber strand 11 is inserted.

In this case, since the cylindrical body constituting the straight member 1A bends with a radius of curvature larger than the minimum bending radius of the fiber strand 11, the fiber strand 11 inserted therein is the inner wall of the deflected cylindrical body. It will bend along.
Note that the term “cylindrical body” as used herein includes both a linear shape and a cone shape.

  The straight members 1, 1 </ b> A, 1 </ b> B are preferably configured such that the elastic coefficient decreases toward the tip.

  In this case, the distal end portion of the fiber strand 11 is bent relatively well due to the bending of the straight members 1, 1 </ b> A, 1 </ b> B, and bending of the entire fiber strand 11 can be suppressed. That is, it is possible to prevent the entire fiber strand 11 from being pulled.

  As described above, according to the present invention, the straight member configured to bend with a radius of curvature larger than the minimum bending radius of the fiber strand of the optical fiber cable exposed by peeling off the outer coating is added to the straight member. Since the fiber strands are arranged so as to bend in accordance with the bending of the fiber, excessive bending of the fiber strands can be prevented even in the straight and curved fiber strands.

The perspective view which shows the bending prevention tool of the optical fiber cable which concerns on one Embodiment of this invention. The side view which shows the state by which the fiber strand was bent. The perspective view of the bend prevention tool which showed the modification of the bend prevention tool of an optical fiber cable, and made the fiber strand directly follow a linear part, and bound the linear part and the fiber strand. The perspective view of the bending prevention tool which showed the modification of the bending prevention tool of an optical fiber cable, and made the fiber strand penetrate the cone-shaped linear member. The perspective view of the bending prevention tool which showed the modification of the bending prevention tool of an optical fiber cable, and extrapolated to the fiber strand the linear member wound helically and in the shape of a cone.

  Hereinafter, an optical fiber cable bending preventer according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the optical fiber cable bend preventer is a straight cable configured to bend with a radius of curvature larger than the minimum bend radius of the fiber strand 11 of the optical fiber cable 10 exposed by peeling off the outer coating. A shaped member 1 is provided.

  The straight member 1 includes a flexible linear portion 2, guide portions 30 and 31 arranged in the linear portion 2 along the axial direction, and the linear portion 2 and the guide portions 30 and 31. And a bundling member 5 for bundling.

  The linear part 2 becomes smaller in diameter toward the tip part, and the elastic coefficient becomes smaller as the diameter becomes smaller. That is, when the transmission loss of the optical fiber cable 10 is taken into consideration, it is preferable that the linear portion 2 bend slightly at the distal end portion rather than bend in the arc shape as a whole. That is, it is preferable that the linear portion 2 bends so that even if a large tensile load is applied to the fiber strand 11, the tensile action can be prevented midway. By doing so, it is possible to notify the operator that the optical fiber cable 10 is being pulled. In addition, when the whole linear part 2 bends in circular arc shape, since the whole bends largely, there exists an advantage which can prevent the cutting | disconnection when a big tensile load is concerned with the fiber strand 11. FIG. Moreover, the front-end | tip part is processed into the hemispherical shape so that the linear part 2 may not damage another wiring cable and arrangement | positioning components (not shown). Examples of the material of the linear portion 2 include strong and flexible materials such as rubber materials, synthetic resin materials, and piano wires.

  The guide portions 30, 31 correspond to the shape of the linear portion 2, the large-diameter first guide portion 30 inserted into the end portion on the outer covering side of the fiber strand 11, and the end portion of the fiber strand 11. And a second guide portion 31 having a small diameter inserted through the second guide portion 31. And each guide part 30 and 31 is comprised by a pair of half crack cylindrical body 30a, 30a, 31a, 31a from which a diameter differs. Moreover, the inner diameter of each guide part 30 and 31 is larger than the outer diameter of the fiber strand 11, and the fiber strand 11 will be in the state inserted loosely. Moreover, when the linear part 2 bends, the outer wall of each guide part 30 and 31 will be located in a substantially tangential direction with respect to the curved surface of the linear member 2. The material of the guide portions 30 and 31 is synthetic resin, but even if the guide members 30 and 31 are bound by the binding member 5, the inner diameter where the fiber strand 11 can be loosely inserted can be maintained and insulation can be secured. Any material can be used.

  The binding member 5 is configured by an insulation tie, and includes an outer covering of the optical fiber cable 10 and a large diameter portion of the linear portion 2, a first guide portion 30 and a midway portion of the linear portion 2, and a second guide portion. 31 and the tip of the linear portion 2 are bound together. In addition, the binding member may be a surface fastener having elasticity or a rubber band. In short, it is only necessary that the above-mentioned portions can be bundled to ensure insulation.

  And although each guide part 30 and 31 is fixed to the linear part 2 by the binding member 5, since the fiber strand 11 is in the loosely inserted state with respect to each guide part 30 and 31, When tension is applied to the fiber strand 11, the fiber strand 11 can freely move inside the guide portions 30 and 31. That is, the fiber strand 11 is bent so as to follow the bending of the linear portion 2. At this time, since the linear portion 2 is configured to bend with a radius of curvature larger than the minimum bending radius of the fiber strand 11, the fiber strand 11 is not excessively bent, and the fiber strand 11 caused by bending. Transmission loss can be prevented.

  Next, the usage mode will be described. An example will be described in which the fiber strand 11 of the optical fiber cable 10 is introduced into the communication device and connected to an optical terminal station disposed in the communication device (in a straight line). In the connected fiber strand 11, the large diameter portion of the linear portion 2 is applied to the end portion on the outer covering side of the optical fiber cable 10, and the large diameter portion of the linear portion 2 is bound by the binding member 5. And the optical fiber cable 10 are bundled. Next, while covering the end part of the outer side of the fiber strand 11 with the inner wall of the half cracked cylindrical bodies 30a, 30a of the first guide part 30, the binding member 5 and the middle part of the linear member 2, The end on the outer covering side of the fiber strand 11 and the first guide portion 30 are bound. And while covering the front-end | tip part of the fiber strand 11 with the inner wall of the half crack cylindrical bodies 31a and 31a of the 2nd guide part 31, the small diameter part of the linear part 2 and the fiber strand 11 of the fiber strand 11 are carried out by the binding member 5. The distal end portion and the second guide portion 31 are bound. By doing so, as shown in FIG. 1, the linear portion 2 is provided along the fiber strand 11. In FIG. 1, the fiber strand 11 in a straight line is illustrated, but even in a curved state, the fiber strand 11, the linear portion 2, each guide portion 30, 31 can be bound by the binding member 5.

  Then, as shown in FIG. 2A, when the fiber strand 11 is bent with tension from the tip end portion to the end portion on the outer covering side, it follows the bending of the linear portion 2 of the straight member 1. Thus, the whole fiber strand 11 comes to curve. At this time, since the linear portion 2 is configured to bend with a radius of curvature larger than the minimum bending radius of the fiber strand 11, even if the fiber strand 11 is pulled with a tension exceeding the minimum bending radius, Excessive bending can be prevented by the shaped part 2. That is, transmission loss of the fiber strand 11 due to bending can be eliminated.

  In addition, as shown in FIG. 2B, when the tension is applied only to the tip of the fiber strand 11, only the tip of the fiber strand 11 is bent. Similarly, since the radius of curvature of the entire linear portion 2 is regulated, the radius of curvature on the distal end side of the linear portion 2 is also regulated, and excessive bending at the distal end portion of the fiber strand 11 is prevented. can do.

  Thus, according to the optical fiber cable of the present embodiment, the fiber strand 11 can be handled regardless of whether it is wired in a straight state or a curved state. In addition, the fiber strand 11 itself can be protected from surrounding members by the straight member 1, that is, the linear portion 2 and the guide portions 30 and 31. Further, the straight member 1 only needs to loosely insert the fiber strand 11 into the guide portions 30 and 31, and does not perform a curing treatment for preventing the bending of the fiber strand 11, and the wiring work is easy.

  The present invention is not limited to the above-described embodiments, and it is free to make design changes, improvements, etc. as necessary and without departing from the spirit of the invention. The combination of is also free.

  For example, in the case of the above-described embodiment, the entire curvature radius of the linear portion 2 is set to be larger than the minimum bending radius of the fiber strand 11, but the linear portion 2 of the linear portion 2 is considered in consideration of this curvature radius. You may make it set so that an elastic coefficient may become small as it goes to a front-end | tip part. In this case, the fiber strand 11 is not pulled more than necessary, and it is preferable that the entire fiber strand 11 bends.

  Moreover, in the case of the said embodiment, although the linear part 2 and each guide part 30 and 31 were provided separately, you may integrate. In this case, each guide portion may hold the fiber strand 11 by elasticity.

  Further, in the case of the above embodiment, the fiber strand 11 is inserted through the guide portions 30 and 31, but the present invention is not limited to this, and the fiber strand 11 is linear as shown in FIG. The fiber strand 11 and the linear portion 2 may be bound by the binding member 5 directly along the portion 2. In this case, the linear portion 2 and the binding member 5 are fixed, and the bending of the fiber strand 11 accompanying the bending of the linear portion 2 is guided while the annular inner wall formed by the binding member 5 is held. There is a need.

  Further, as shown in FIG. 4, a straight member 1 </ b> A composed of a cone-shaped (conical) cylindrical body having a diameter that decreases toward the tip may be extrapolated to the fiber strand 11. . By doing so, the fiber strand 11 is inserted inside the straight member 1A. The straight member 1A is designed to bend with a radius of curvature larger than the minimum bending radius, and to have a smaller elastic coefficient toward the tip. In this case as well, when the fiber strand 11 is pulled, the fiber strand 11 bends along the inner wall of the straight member 1A as in the above embodiment. Further, the straight member 1A may be a linear cylinder. In either case, since the fiber strand 11 is inserted into the straight member 1A, the guide portions 30 and 31 and the bundling member 5 become unnecessary.

  Further, as shown in FIG. 5, a straight member 1 </ b> B made of a coil spring wound in a spiral shape so that its outer shape is a cone shape may be extrapolated to the fiber strand 11. Then, the support shaft 15 extended outward from the base end portion (large diameter portion) of the straight member 1B along the axial direction is applied to the end portion on the outer covering side of the optical fiber cable 10 and bound. The straight member 1 </ b> B and the optical fiber cable 10 are bound by the member 5. In this case, since the straight member 1B is a coil spring, the straight member 1B is configured to return to its original state with respect to bending, that is, to be linear, and is configured to bend with a curvature radius larger than the minimum bending radius. Yes. And when the fiber strand 11 is pulled, this fiber strand 11 comes to bend along the inside of the linear member 1B. As in the case of FIG. 4, the straight member 1 </ b> B may be a coil spring wound linearly. Also in this case, the guide portions 30 and 31 and the binding member 5 are not necessary.

  The reason why the straight members 1, 1A, 1B are formed so as to become smaller in diameter toward the tip is that the elastic modulus is reduced toward the tips of the straight members 1, 1A, 1B. This is because it is easy.

  The straight members 1, 1 </ b> A, 1 </ b> B are along the fiber strand 11 while being fixed to the end portion of the optical fiber cable 10, but may be directly fixed along the fiber strand 11. .

  DESCRIPTION OF SYMBOLS 1,1A, 1B ... Straight member, 2 ... Linear part, 5 ... Bundling member, 10 ... Optical fiber cable, 11 ... Fiber strand, 15 ... Support shaft, 30, 31 ... Guide part, 30a, 31a ... Tube Body

Claims (4)

Bending of the optical fiber cable that prevents the fiber strand (11) of the optical fiber cable (10) exposed by peeling off the outer coating from being bent with a radius of curvature equal to or less than the minimum bending radius of the fiber strand (11). In the prevention tool,
The tip of the fiber strand (11) has one end disposed to face the tip of the fiber strand (11) and the other end facing the outer sheath of the optical fiber cable (10). The one end side is fixed to the optical fiber cable (10), and the other end side is fixed to the outer sheath of the optical fiber cable (10).
The straight member (1, 1A, 1B) is configured to bend with a radius of curvature larger than the minimum bending radius of the fiber strand (11), and to bend according to the bending, the fiber strand (11). , And one end side of the straight member (1, 1A, 1B) is configured to bend more than the other end side of the straight member (1, 1A, 1B). Ingredients. The straight member (1) includes a flexible linear portion (2) and a guide portion that is disposed along the axial direction of the linear portion (2) and into which the fiber strand (11) is loosely inserted. The optical fiber cable bend preventer according to claim 1, wherein The said straight member (1A) is comprised with the cylindrical body by which a fiber strand (11) is penetrated inside, The bending prevention tool of the optical fiber cable of Claim 1 characterized by the above-mentioned. The optical fiber cable bend preventer according to any one of claims 1 to 3, wherein the straight member (1, 1A, 1B) has an elastic coefficient that decreases toward the tip.

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