JP4387322B2 - Conversion structure of metal tube optical fiber cable - Google Patents

Description

  The present invention relates to a conversion structure for a metal tube optical fiber cable.

  In a metal tube optical fiber cable in which the optical fiber core wire is inserted into the metal tube, the end portion side of the metal tube is removed by a predetermined length to expose the optical fiber core wire to the outside of the metal tube. It is widely practiced to insert an optical fiber core wire into a tube, convert it into an optical fiber cord, and connect it to a predetermined circuit via a connector.

  On the other hand, in a structure in which an optical fiber core wire exposed from a metal tube of a metal tube optical fiber cable is inserted into a tube and converted into an optical fiber cord, the conversion transition portion from the metal tube to the tube is protected. It is disclosed in Patent Document 2.

  In Patent Document 1, the end of a protective tube is put on the end of a metal tube into which a single-core or multi-core optical fiber is inserted to form a conversion transition portion, and a compression sleeve is formed on the protection tube at the transition portion. A structure is disclosed in which the compression sleeve is crimped and fixed to a metal tube, and a protective boot is placed on the compression sleeve.

Moreover, in patent document 2, both the outer peripheral surfaces of both are covered with a heat-shrinkable tube so that it may reach both a metal tube and a tube in a transition part, and this heat-shrinkable tube is heat-shrinked. To secure the protection.
JP 2004-133210 A JP 2000-75178 A

  However, Patent Document 1 and Patent Document 2 describe that the optical fiber core wire inserted into the metal tube can be applied to a single core or a multi-core, but the optical fiber core wire is a single tube. Therefore, even in the case of a multi-core optical fiber cable, the plurality of optical fiber cables are accommodated in this one tube as a bundle. That is, it is not a structure in which each optical fiber core wire is covered with a tube for branch conversion.

  In Patent Document 1, since the protective tube is fixed to the metal tube by caulking the sleeve, it is considered that the strength against tension and torsion is high. However, since the tube is fixed to the metal tube, a plurality of tubes cannot be fixed, that is, branched in this structure.

  Further, Patent Document 2 has a problem in strength, and some problems occur when applied to a branch conversion structure.

  First, in Patent Document 2, although it may be possible to branch into a plurality of tubes, no consideration is given to the improvement of strength, which is insufficient in terms of strength.

Next, when the number of optical fiber cores increases, the thickness of the side covering one metal tube and the side covering a plurality of optical fiber cords are greatly different when branching conversion is performed. The shrinkage of the heat-shrinkable tube cannot cope with this difference in thickness, and sufficient holding ability cannot be obtained. In order to cope with this, the heat shrinkable tube itself must be made to have a special size and shape, which is not realistic.

  Furthermore, the holding by the heat-shrinkable tube has a low strength against torsion around the axis of the metal tube optical fiber cable and cannot provide sufficient protection. Even if the holding with the adhesive is performed, the strength against torsion is not improved so much. This is because the adhesive cannot sufficiently resist the circumferential shearing force with the tube surface. In addition to this, it takes a long time to cure the adhesive, and if an external force is received before it has been cured, adhesion failure occurs.

  SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a metal tube optical fiber cable conversion structure that can sufficiently secure strength and that can be branched and converted into a plurality of optical fiber cords by covering a plurality of optical fiber cables. With the goal.

Converting structure of the metal tube optical fiber cable according to the present invention, the optical fiber core wire that is inserted into the metal tube, by removing the front end side of the metal tube by a predetermined length, is exposed to the metal tube outer The exposed optical fiber core wire is inserted into a tube and converted into an optical fiber cord, and the metal tube and the optical fiber cord are protected by a protective member in the conversion region.

In such an optical fiber cable conversion structure, in the present invention, the protective member has a protective member main body and a lid member, and the protective member main body is a cut groove portion extending in the axial direction over the entire length at one place in the circumferential direction. And the inner and outer spaces of the protective member body are communicated with the cut groove portion, and a recess for receiving the optical fiber cable is formed in the cut groove portion so as to communicate with the cut groove portion. the lid member is adapted to close the said cut groove portion is attached to the cut groove, the recess forward position than the first support portion and said first supporting portion for receiving and supporting the front end of the metal tube in and a second support portion for receiving and supporting an end portion after the optical fiber cord, a metal tube having a supported portion in cross-section is non-circular in front end side, the first support portion, Locking portion for storing the supported portion, and behind the supported portion And a guide portion to accommodate a portion of the metal pipe positioned, and the locking portion is name a matched shape so as flush contact with the outer surface of the supported portion without a stepped adjacent inside the guide It is characterized by being.

In the present invention having such a configuration, the supported portion formed in the metal pipe, so has a shape that is deformed so that the cross-section having a portion forming a non-circular, contact surface held to said support section It is fixedly supported by a locking portion formed on the first support portion of the protective member. In other words, a sufficient locking force is generated against the external force in the cable axis direction and the torque around the axis. Moreover, since the supported portion is made of metal, the locking force is extremely large.

  Therefore, since the metal tube is held firmly in this way, the external force and torque are not transmitted to the converted optical fiber cord, and the load is only a force acting from the optical fiber cord side, which is small, It can be received by the second support part sufficiently.

  In addition, there is a possibility that a bending force may also act on the metal tube or the optical fiber cord, but this is sufficient because the first first support portion and the second support portion respectively support the contact surface. It becomes.

  In the present invention, a plurality of optical fiber cores may be inserted into the metal tube, and the exposed plurality of optical fiber cores may be branched and inserted into individual tubes. For the branch conversion site, the second support portion of the protective member may be made in conformity with the shape and size of the site, so that sufficient support can be performed regardless of the number of branches. Such a 2nd support part can make a protection member by molding, for example.

  In the present invention, the supported portion can be made such that a part of the outer surface of the metal tube is subjected to plastic deformation.

  According to this method, since the above-mentioned part of the metal tube is only plastically deformed, the processing is simple and easy. An example of the plastic deformation is a process in which a metal tube is crushed in a specific radial direction and swelled in another radial direction in a cross section perpendicular to the axis.

  Alternatively, the supported portion may be formed by fixing another pipe member to a part of the outer surface of the metal pipe.

  According to this method, the shape and size of another pipe member can be arbitrarily selected, and further, plastic deformation processing can be performed in a desired shape in advance, so that a large load is not applied to the metal pipe. A shape change can be obtained, and a large locking force can be obtained.

  The another pipe member may be fixed to a metal pipe by caulking, or may be fixed by adhesion, or may be fixed by both.

The supported portion is preferably formed formed adjacent to Motogai径portion of definitive axial end edge of the metal tube. By doing so, against the external force in the axial direction, a locking force is generated in the external force in both directions in the axial direction, and the strength is also improved.

  The protective member is preferably fitted with a sleeve for holding the lid member. The sleeve enhances protection and reliably prevents the cover member from coming off.

  When a tensile strength fiber is provided inside the tube, it is preferable that the extra length portion of the tensile strength fiber extending from the end of the tube is fixed to the protective member. Holding strength is further increased by fixing the extra length of the tensile strength fiber. This fixing may be a mechanical method or a method using an adhesive.

  For example, the extra length portion of the tensile strength fiber is drawn out to the outer surface of the protective member through a window portion or a notch groove formed in the protective member so as to communicate with the outside from the second support portion, and is fixed to the outer surface. be able to. The holding strength is further enhanced by the extra length of the tensile strength fiber engaging with the window or the notch.

  As described above, the present invention supports the metal tube and the optical fiber cord by the protection member in the conversion region, and the supported portion of the high-strength metal tube has the locking portion of the protection member in the axial direction and the circumferential direction. Since it is locked, not only can a sufficient resistance to the tensile force be obtained, but also a high resistance can be obtained against torsion, resulting in a high degree of protection. Furthermore, since the shape and size of the first support portion and the second support portion of the protection member can be set as appropriate, even if the number of optical fiber cores branched from the metal tube is increased somewhat, this can be sufficiently accommodated.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an outline of a branch conversion structure of a metal tube optical fiber cable according to the present invention.

In FIG. 1, an optical fiber cable formed by inserting a plurality of optical fiber core wires into a metal tube cable 14 is exposed from a metal tube (not shown) by removing a predetermined length of the end side of the metal tube (not shown). Each of the formed optical fiber core wires is covered with a tube 2 and branched and converted into each optical fiber cord. This branch conversion site is supported and protected by the protective member 3. Each optical fiber cord is connected with a connector 4 so that it can be connected to a predetermined circuit.

  In the case of this embodiment, the protection member 3 shown in FIG. 1 has a protection member main body 5, a lid member 6, and a sleeve 7 made by molding synthetic resin. In FIG. 1, the protection member main body 5 and the lid member 6 are shown as being cut in a single plane including the axis of the protection member 3, and are made symmetrical with respect to the plane.

As shown in FIG. 2, the protective member 3 has a substantially cylindrical outer peripheral surface, and opens upward at one place in the circumferential direction (a position facing upward in the figure) and penetrates in the longitudinal direction to be recessed. A place is formed. This recess forms a cut groove 8 that forms an opening on the outer peripheral surface side, and forms a first support 9 that supports the metal tube 1 and a second support 10 that supports the optical fiber cord at the axial position. To do. That is, the lid member 6 is positioned at the position of the cut groove portion 8 and the cut groove portion 8 is closed, and the first support portion 9 and the second support portion 10 are continuously connected to the axial position of the protection member 3. A hollow space that can penetrate through is formed.

  The inner wall surface 8 </ b> A of the cut groove 8 is parallel to the plane taken in the cross section in FIG. 2, and the width between the opposed inner wall surfaces 8 </ b> A is the same as the width of the lid member 6.

  The first support portion 9 is recessed from the surface of the seat 11 formed to receive a part of the lid member 6 and forms a space for accommodating the metal tube 1 of the optical fiber cable. The first support portion 9 is located on the left end side in FIG. 2 and has a side having a length equal to the base outer diameter of the metal tube 1 (referred to as the outer diameter when the metal tube is not subjected to any plastic deformation). A guide portion 9A having a square cross section (a cross section in a plane perpendicular to the axis), and a locking portion having a step shape adjacent to the guide portion 9A and having a square cross section whose sides are longer than the guide portion 9A. 9B. The engaging portion 9B has a shape and a size that fits a supported portion of the metal tube 1 described later and supports the contact surface.

A region on the right side from the first support portion 9 forms a second support portion 10. It said second support portion 10 is formed so as to extend the cut groove 8 in the depth direction, than the lower surface of the engaging portion 9B of the first support portion 9 extends to a lower, to the cut groove 8 The outline of the space of the second support portion 10 formed when the lid member 6 is disposed forms a square that is concentrically located outside as viewed from the axial direction with respect to the outline of the space of the locking portion 9B. The space of the second support portion 10 has a size suitable for accommodating a plurality of optical fiber cords that are exposed from a metal tube, covered with a tube, and branched and converted.

  The protective member main body 5 has an inner space communicating with the outside by a notch groove 12 formed laterally at an intermediate portion of the second support portion 10 in the axial direction. The cutout groove 12 extends upward to the wall portion of the cutout groove portion 8 and opens at the upper end. The notch groove 12 may be formed as a window portion even if it is not opened upward.

  The protective member main body 5 is a portion on the left side of the notch groove 12 and has an outer peripheral wall parallel to the cut groove portion 8 and the inner wall surface 8A and the inner wall surface 10A of the second support portion 10 located in the extension thereof. A flat surface 13 is formed so as to be cut.

The lid member 6 attached to the protective member main body 5 has the same length as the protective member main body 5 in the axial direction, has a width that can be accommodated in the cut groove portion 8, and a part of the lower surface thereof is the receiving portion. A square space formed when viewed in the axial direction when supported by the seat 11 is a locking portion 9B of the first support portion 9, a guide portion 9A of the first support portion 9, and a second support. Step portions 6A, 6B, 6C are formed so as to increase in the order of the portion 10. Further, the upper surface 6D of the lid member 6 forms a part of the cylindrical surface so as to form one cylindrical surface together with the outer peripheral surface of the protective member main body 5.

  Furthermore, the sleeve 7 is made as a hollow cylindrical body having a dimension that is fitted to the protective member main body 5 while sliding in the axial direction when the lid member 6 is attached, and the length in the axial direction is also the above-mentioned protective member. The main body 5 and the lid member 6 are the same.

  Next, as shown in FIG. 3A, which shows a plan view of the metal tube optical fiber cable housed in the protective member main body 5, the metal tube 1 is removed from the end portion by a predetermined length. A stepped supported portion 1 </ b> A is formed at a portion of the new end portion side of 1. The metal tube 1 is subjected to plastic deformation so that the supported portion 1A has a stepped diameter larger than the base outer diameter of the metal tube 1 so that the supported portion 1A can be accommodated in contact with the locking portion 9B of the protective member body 5. Received and formed. In the example shown in the figure, the supported portion 1A is processed so that the outer peripheral cross section becomes a square so as to contact the locking portion 9B, or another pipe member having a square outer peripheral cross section is a metal tube. It is attached by caulking, bonding, or both.

  The shape of the cross-section of the outer peripheral surface of the supported portion is not limited to a square, and may be a non-circular shape. For example, various shapes such as other polygons, shapes in which irregularities are alternately formed in the circumferential direction, and ellipses are possible. In this case, the locking portion 9B also has a shape that matches these shapes.

  Preferably, a portion of a base outer diameter circle is left at the end adjacent to the supported portion in the axial direction. Therefore, the locking portion also has a shape portion that contacts the portion of the base outer diameter circle.

  Such a metal tube optical fiber cable forms a branch conversion structure into an optical fiber cord in a state protected by the above-described protective member in the following manner.

  (1) First, the coating is removed by a predetermined length on the end portion side of the metal tube optical fiber cable to expose the metal tube.

  (2) Next, the metal tube is removed by a predetermined length on the end portion side of the metal tube to expose a plurality of optical fiber core wires.

  (3) Next, the supported portion 1A is formed or attached to the metal tube 1 on the new end side of the metal tube as described above.

  (4) After that, as shown in FIG. 3 (A), each of the optical fiber core wires to be exposed is covered with a tube 2 and branched. In the example shown in the drawing, the optical fiber cable F shows four cases forming two rows and two stages as seen in FIG. 3B described later. The case where the tensile strength fibers 2A for improving the strength are internally provided in the tube 2 is shown, and the extra length of the tensile strength fibers 2A is exposed by removing the end portion of the tube skin.

  (5) In such a state, as shown in FIG. 3A, the branch conversion portion of the optical fiber cable is inserted from the cut groove portion 8, the metal tube 1 is arranged on the first support portion 9, and the supported portion 1A is Store in the locking portion 9B.

(6) On the other hand, the optical fiber cord is arranged on the second support portion 10 in a state in which the extra length portion of the tensile strength fiber 2A is drawn out from the cutout groove 12 of the protective member body 5. Therefore, the tip of the tube 2 is located in the vicinity of the notch groove 12.

  (7) Thereafter, the extra length portion of the tensile strength fiber 2 </ b> A is fixed to the flat portion 13 formed on the side surface of the protection member body 5 by mechanical means or an adhesive.

  (8) Then, as shown in FIG. 3B, the lid member 6 is attached to the protective member main body 5 so as to hold the metal tube and the optical fiber cord, and then the sleeve 7 is fitted to both. The lid member 6 and the sleeve 7 may be fixed using an adhesive as necessary. Thus, the work for branch conversion of the optical fiber cable is completed. In the metal tube, the supported portion 1A is locked at the step portion between the locking portion 9B and the guide portion 9A of the first support portion 9 and the end portion of the cable covering in the axial direction, and the supported portion in the circumferential direction. Since the non-circular shape of 1A engages with the engaging portion 9, the engaging force acts on the external force in the axial direction and the torque around the axial line. And since it is a metal, the intensity | strength at that time is large. The optical fiber cord is supported in contact with the second support portion 10.

  In the present invention, a plurality of optical fiber cables are each covered with a tube for branch conversion. However, the present invention is not limited to this, and a plurality of optical fiber cables may be covered with one tube at a time, or two or three. You can also put these on top of each other. Furthermore, the present invention can be applied to a conversion structure of a single optical fiber cable.

It is a schematic diagram which shows the conversion structure of the metal tube optical fiber cable of this invention. It is a perspective view in the state by which the protection member used in Drawing 1 was cut. It is a figure when an optical fiber cable is stored in a protection member, (A) is a top view before cover member attachment, (B) is a longitudinal cross-sectional view after cover member attachment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal tube 1A Supported part 2 Tube 2A Tensile fiber 3 Protection member 6 Lid member 7 Sleeve 8 Cut-out groove part 9 First support part 9A Locking part 10 Second support part 12 Notch groove 13 Flat surface 14 Cable

Claims (9)

An optical fiber that is inserted into the metal tube, by removing the front end side of the metal tube by a predetermined length, is exposed to the metal tube outer, the exposed optical fiber is inserted into the tube In the optical fiber cable conversion structure for converting into an optical fiber cord and protecting the metal tube and the optical fiber cord with a protective member in the conversion region, the protective member has a protective member body and a lid member, and the protective member The main body is formed with a cut groove portion extending in the axial direction at one place in the circumferential direction, and the inner and outer spaces of the protective member main body communicate with each other through the cut groove portion, and an optical fiber cable is formed inside the cut groove portion. the has recesses are formed in communication with the groove preparative該切fit, the lid member is attached to the cut groove being adapted to close the cut groove, the recesses front end of the metal tube Contain and support And a second support portion for receiving and supporting an end portion after the optical fiber cord in a forward position than the first support portion and said first support portion, the metal tube was cross-section a non-circular in front end side The first support portion includes a locking portion that houses the supported portion, and a guide portion that accommodates a portion of the metal tube positioned behind the supported portion. stop unit conversion structure of a metal tube optical fiber cable characterized in that it Na conformance shape to face contact with the outer surface of the supported portion without a stepped adjacent inside the guide.   The metal tube optical fiber according to claim 1, wherein a plurality of optical fiber core wires are inserted into the metal tube, and the exposed plurality of optical fiber core wires are branched and inserted into individual tubes. Cable conversion structure.   The metal tube optical fiber cable conversion structure according to claim 1, wherein the supported portion is made by subjecting a part of the outer surface of the metal tube to plastic deformation.   2. The metal tube optical fiber cable conversion structure according to claim 1, wherein the supported portion is formed by fixing another tube member to a part of the outer surface of the metal tube.   5. The conversion structure for a metal tube optical fiber cable according to claim 4, wherein another tube member constituting the supported portion is caulked and fixed to the metal tube. The supported portion is, claim 3 or metal tube optical fiber cable according to one of claims 5 and that is formed adjacent to the Motogai径portion of definitive axial end edge of the metal tube Conversion structure. The metal tube optical fiber cable conversion structure according to claim 1 , wherein a sleeve for holding the lid member is fitted on the protective member.   2. The metal tube optical fiber according to claim 1, wherein a tensile strength fiber is provided inside the tube, and an extra length portion of the tensile strength fiber extending from an end of the tube is fixed to a protective member. Cable conversion structure. The excess length portion of the tensile strength fiber is pulled out to the outer surface of the protective member through a window portion or a notch groove formed in the protective member so as to communicate with the outside from the second support portion, and is fixed to the outer surface. metal tube optical fiber converts the cable construction described in 8.

Images