JPH0438325Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a clamp for an optical fiber cord.

[Conventional technology and its problems]

Conventionally, clamps used to securely hold optical fiber cords to optical fiber cable termination junction boxes, etc. have shapes and structures as shown in FIGS. 10, 11, and 12, for example. Are known.

That is, a presser plate b having a plurality of V grooves a,
An angled or similar receiving member c is tightened with a bottle or the like (not shown), and the fiber cords e are arranged and fixed in the horizontal direction.

Such a conventional optical fiber cord clamp f has the following problems.

The shape and dimensions of the V-groove a must have high machining accuracy, making the structure complicated and expensive.

When used in a termination junction box g as shown in FIG. 10, the space indicated by diagonal lines in the figure could not be used. The reason for this is that there is a risk that the fiber core of the fiber cord may be bent and damaged if the optical fiber cord hits the hand during work.

Further, although it is not a clamp for optical fiber cords, a housing fixture for an optical fiber connection portion is known, as described in Japanese Utility Model Application Laid-open No. 175106/1983. This accommodation fixture is
A protective sleeve, which is an inelastic body that protects the optical fiber connection, is held by the elastic force of a groove formed in an elastic block such as rubber, and the protective sleeve is fixed by being slightly pressed by a fixed cover. .

However, in order to use such a conventional housing fixture as a clamp for an optical fiber cord, the optical fiber cord must be fixed in the groove,
The accommodation fixture is fixed near the opening at the end of the junction box to hold the optical fiber cord coming out from the junction box. If the optical fiber cord swings in the groove depth direction of the groove, there is no room for the optical fiber cord to move within the groove due to the swing. Local bending occurs at the open end in the longitudinal direction of the optical fiber cord, causing problems such as damage to the fiber core of the optical fiber cord and increased optical transmission loss. Another problem is that it is troublesome to fit a large number of optical fiber cords into the grooves of the housing fixture. Furthermore, since the shape of the elastic block is complex and requires precision, there is a problem in that manufacturing is time-consuming and expensive.

[Means for solving problems]

Therefore, in order to solve the above-mentioned problems, an optical fiber cord clamp according to the present invention has a plurality of comb-shaped clamping grooves each consisting of both parallel side surfaces and a bottom surface perpendicular to the both sides. The main body is made of an inelastic material, the both side surfaces and the bottom are smooth surfaces with no steps, and the groove width of the groove is set smaller than the outer diameter of the fiber cord in its free state. The groove depth of the groove is set larger than the outer diameter, the fiber cord is elastically deformed and clamped on both sides of the groove, and the clamp body is fixed to a holder, The opening facing the bottom surface of the groove is closed.

[Effect]

Since the comb-shaped clamping groove only needs to be machined with high accuracy in the gap between the two parallel opposing faces, and such two parallel faces can be easily machined with high precision, manufacturing is significantly facilitated. Furthermore, the fiber core wire of the optical fiber cord is weak against bending and the loss increases, but it is strong against compression in the radial direction and does not cause loss, so the pressing by the comb-shaped clamping grooves Clamping is advantageous in terms of fiber strength and loss reduction.

Since the optical fiber cord has a large degree of freedom in the groove depth direction within the clamping groove, even if the optical fiber cord swings in the groove depth direction of the groove, the opening in the longitudinal direction of the groove No local bending occurs at the ends. In addition, even if a large tensile force is applied to the optical fiber cord, it is possible to prevent the cord from being stuck due to the step part created when the optical fiber cord is elastically clamped in the clamping groove and the opening end in the longitudinal direction of the groove. The above-mentioned tensile force can be withstood by the stopping force and the frictional holding force due to elastic clamping. Moreover, in the work of sequentially inserting multiple optical fiber cords into the clamping groove,
Since it is held by the above-mentioned elastic clamping, it can be easily assembled into the holder without coming off once inserted.

〔Example〕

Hereinafter, the present invention will be explained in detail based on the illustrated embodiments.

In FIG. 3, an optical fiber cable termination junction box 1 is illustrated, and 2 and 3 are optical fiber cables 3 and 3.
Cable clamps 4, 4 for fixing the cables 3, 3 respectively are tension member clamps for fixing the tension members 5, 5 of the cables 3, 3, and 6... are fiber core wires extending bare from the ends of the cables 3. Then, it is stored in the central extra connection length storage section 7 in the form of a roll.

8 is a clamp for an optical fiber cord to which the present invention is applied, and the optical fiber cord 9...
In Fig. 3, it is arranged at the lower right corner of the junction box main body 10 which is rectangular in plan view, and forms a vertical correspondence position with the cable clamps 2, 2 arranged at the upper right corner. After coming in as 3,3,
As a whole, we made a U-turn and optical fiber code 9...
and leaves. A connector is attached to each end (not shown) of the fiber cords 9....

An enlarged cross-section of this optical fiber cord 9 is illustrated in FIG. That is, primary and secondary coating layers 12 and 13 are provided on the outside of the fiber wire 11 to constitute the fiber core wire 6, and the fiber core wire 6 is coated with a fiber reinforcing layer 14 such as a longitudinal layer of Kevlar. Furthermore, a jacket 15 is covered from above.

FIG. 9 is a view seen from the right side of FIG. 3, and it can be seen that the clamp 8 of the present invention is provided at the left end of FIG. 9, and the cable clamps 2, 2 are provided at the right end.

In the embodiment shown in FIGS. 1 and 2, numeral 16 is a clamp body made of an inelastic material made of metal or hard plastic, and numeral 17 is a channel-shaped holder. The clamp body 16 is
Parallel both side surfaces 27, 27 and both side surfaces 27, 27
The clamp body 16 has a plurality of comb-shaped clamping grooves 18 each having a bottom surface 30 orthogonal to the clamp body 16.
A plurality of comb-shaped grooves 18 are formed on both the left and right sides of the groove. Both sides of groove 18 27.27
The bottom surface 30 is a smooth surface with no steps, and as described later, both side surfaces 27 are two parallel opposing upper and lower surfaces.
27, the fiber cord 9 can be clamped by elastically deforming it in the inner diameter direction. The clamp body 16 also has one hole 19 at the top and bottom.
is provided through it, and the groove width dimension H of this groove 18 is
is set slightly smaller than the outer diameter dimension D of the fiber cord 9 in its free state, and the groove depth dimension P is set larger than the outer diameter dimension D mentioned above. In other words, H
Set so that <D<P.

Further, a screw hole 21 is provided in the bottom wall 20 of the holder 17.
be installed throughout. The fiber cord 9 has a clamping groove 1
8 from the lateral direction by utilizing their respective elastic deformations, it is held in a pressed state within the groove 18. That is, the fiber cord 9 is clamped on the two parallel opposing upper and lower surfaces of the groove 18.

Thereafter, as shown in FIGS. 1 and 2, the clamp body 16 is fitted into the recess 22 of the holder 17, the openings facing the bottom surfaces 30 of the clamping grooves 18 are closed, and the screw rods are tightened. 23 is inserted into the hole 19 and screwed into the screw hole 21 to be assembled integrally.
In FIGS. 1 and 2, some of the fiber cords 9 are omitted, and generally all the concave grooves 18 are shown.
One by one is kept inside. The depth of the recess 22 is set to be approximately the same as the height of the clamp body 16, and the width of the recess 22 is set to be approximately the same as the width of the clamp body 16. As shown in FIG. 2, the outer shape is a rectangular parallelepiped, and the fiber cords 9 are securely held in the respective grooves 18.

Next, FIG. 4 shows another embodiment. That is, the hole 19 (see FIG. 1) is omitted in the clamp body 16, and instead, screw holes 21a are provided in the upper surfaces of the left and right side walls 24, 24 of the holder 17, and the holes 25
Add a presser plate 26 with... Furthermore, the height dimension of the clamp body 16 is set slightly larger than the depth dimension of the recess 22 of the holder 17, and the screw rod 23
... is inserted into the hole 25 and screwed into the screw hole 21a, thereby closing each opening facing the bottom surface 30 of the clamping groove 18 and integrally assembled.

In addition, as shown in FIG. 5, the vertically long holder 17
It is also possible to adopt a structure in which two or more clamp bodies 16 are fitted into the recesses 22 of the clamp bodies 16. Although not shown, in Figures 1 to 5,
A comb-shaped groove 18 is formed on both the left and right sides, but in addition to this, a comb-shaped groove 1 is formed only on one side.
You are free to form 8... in parallel.

Therefore, the structure and operation of the above-mentioned embodiment will be explained in the sixth embodiment.
The principle is shown in FIG. That is, the groove width H of the concave groove 18 is set smaller than the outer diameter D of the fiber cord 9, and in the fixed state, as shown in FIGS.
As shown in the figure, the fiber cord 9 is elastically deformed and held on both side surfaces 27, 27 of the concave groove 18 so as to be compressed in the inner diameter direction, so there is little light transmission loss and mechanical strength is improved. Not damaged. Then, stepped portions 31, 31 are generated in the fiber cord 9 due to elastic deformation during clamping, but even if a large tensile force is applied to the fiber cord 9 in this fixed state, the stepped portion 31 is , by engaging the longitudinal open end 32 of the groove 18, and by the frictional holding force of the elastic contact accompanying the elastic deformation,
It can withstand the above tensile force and the fiber cord 9 will not be pulled.

Further, since the groove depth dimension P of the groove 18 is set larger than the outer diameter dimension D, as shown in FIG. In the fixed state, the fiber cord 9 exiting from the junction box 1 to the outside and the fiber core wire 6 extending naked from the end of the fiber cord 9 are connected to the concave groove 1 shown in FIG.
Even if the fiber cord 9 swings in the groove depth direction of 8 (the plane direction of the connection box 1 shown in FIG. 3), the fiber cord 9 moves in the groove depth direction within the concave groove 18 with the swing. Therefore, local bending does not occur at the longitudinal open ends 32, 32 of the groove 18.

[Effect of idea]

The present invention has the following significant effects due to the above-described configuration.

Since the optical fiber cord 9 is elastically deformed and held on both side surfaces 27, 27 of the holding groove 18, the optical fiber cord 9 is compressed and held in place, so that light transmission loss is small and mechanical strength is not impaired.

In the fixed state of the fiber cord 9, even if a large tensile force is applied to the fiber cord 9, the elastic frictional holding force between the both sides 27, 27 of the clamping groove 18 is reduced due to the elastic deformation of the fiber cord 9 itself. It occurs largely, and the step part 31 and the open end part 3
2 is also added, and the fiber core wire 6
It can withstand the above tensile force without damaging it.

Since both side surfaces 27, 27 and bottom surface 30 of the groove 18 are smooth surfaces with no steps, the fiber cord 9 can be quickly and easily inserted into the groove 18 from any direction. It can be inserted at any position in the longitudinal direction, making it extremely easy to work.

The shapes and structures of the clamp body 16 and holder 17 are extremely simple, so they are easy to manufacture.
The groove width dimension H of 7 and 27 can also be manufactured at low cost because it is relatively easy to obtain high machining accuracy.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention;
Fig. 2 is a perspective view of the assembled state; Fig. 3 is a plan view showing an example of application to an optical fiber cable termination/junction box; Fig. 4 is a partially cutaway front view showing another embodiment;
5 is an exploded front view of another embodiment, FIG. 6 is a diagram for explaining the principle, FIG. 7 is a sectional side view for explaining the principle, and FIG. 8 is an enlarged cross-sectional view showing an example of an optical fiber cord.
FIG. 9 is a right side view of FIG. 3. FIG. 10 is an overall perspective view showing a conventional example, FIG. 11 is an enlarged exploded view of essential parts, and FIG. 12 is a diagram explaining the principle of a conventional clamp. 9... Optical fiber cord, 18... Clamping groove.

Claims (1)

[Scope of utility model registration request] A clamp body having a plurality of comb-shaped clamping grooves each having parallel side surfaces and a bottom surface orthogonal to the both sides is formed of an inelastic material, and the both side surfaces and the bottom surface are formed without any step. The groove width of the groove is set to be smaller than the outer diameter of the fiber cord in its free state, and the groove depth of the groove is set to be larger than the outer diameter of the fiber cord. The optical fiber cord is characterized in that the fiber cord is elastically deformed and clamped on both sides, and the clamp body is further fixed to a holder to close an opening facing the bottom surface of the groove. clamp.