Apparatus and method for sending out linear material

Abstract: A arrangement is provided for paying-out a linear material. The method includes rotating a frame in a direction to pay-out the material; rotating a reel to unwind the material therefrom; utilizing a capstan assembly to restrict a pay-out speed of the material; applying a prescribed tensile force to the material by use of a dancer member disposed near the capstan assembly; detecting a position of the dancer member; and controlling the pay-out speed by the capstan assembly to keep the detected position unchanged.

Description: Field of the Invention The present invention relates to an apparatus and method for paying out a linear material such as a slot rod for manufacturing an optical fiber cable of the ribbon-slot type. Background of the Invention An ordinary grooved slot rod 11 is shown in FIG. 2. Slot rod 11 includes a body 13 having a single or plurality of spiral grooves 14 formed on the outer circumferential surface thereof and extending at a certain spiral pitch along the longitudinal direction of the body. A tension-withstanding wire 12 is provided in the central portion of the body. To assemble a ribbon-slot type optical fiber cable including rod 11 and optical fiber tapes, the rod is pay out from a reel, and the ribbons are inserted into the spiral grooves 14 of the body 13 of the rod by an insertion device. Since the spiral grooves 14 are formed spirally along the longitudinal direction of the body 13, the optical fiber ribbons need to be guided into the grooves. FIG. 3 shows a conventional apparatus for paying out a slot rod 11. The apparatus includes a reel 101 having a rod 11 wound thereon in advance, a frame 102, a rotary shaft 103 supporting the reel at one end of the frame so as to pay out the rod in a direction perpendicular to the axis of the shaft, a disk 104 fastened to the frame, a pair of rollers 105 supporting the disk, a support member 106 for supporting the frame, and guide rollers 107 and 108 attached to the frame to guide the rod. The frame 102 can be rotated about the paying-out direction of rod 11, synchronously with the turning of the spiral grooves 14 thereof, by a driver (not shown). A caterpillar-type braking device 109 is provided next to the apparatus in order to apply a desired tensile force to the rod 11. The braking device includes caterpillars 112 supported by pairs of rollers 110 and 111 extending over and under the rod 11 being pay out. The caterpillars 112 can be rotated about the paying-out direction of the rod 11, synchronously with the turning of the spiral grooves 14 thereof, as well as the frame 102 of the apparatus. In the conventional apparatus, the reel 101 is rotated about the rotary shaft 103 and the frame 102 is rotated about the paying-out direction of the rod 11, so that the rod is unwound from the reel and thus, pay out. In the braking device, the rod 11 is pushed between the upper and the lower caterpillars 112 so that the desired tensile force may be applied to the rod. The tensile force applied to rod 11 by the caterpillar-type braking device 109 while being pay out by the conventional apparatus, is unstable due to changes in the pushing forces of the caterpillars 112 on the rod, and to frictional forces on the rotary sliding portions of the apparatus. Thus, the conventional apparatus does not ensure a consistent tensile force in operation. In addition, since the braking device 109 is provided separately from the paying-out apparatus, the size of an entire machine is large. JP-A-5898489 discloses a twist machine for twisting together a pair of electric wires. For each electric wire an assembly is provided from which the electric wire is paid-out. The different assemblies rotate around a central axis which is in alignment with the direction in which the twisted wire is paid-out. Each assembly comprises a reel on which the electric wire is wound on, a capstan assembly for restricting pay-out speed of the electric wire, as well as a dancer member for applying a prescribed tensile force to the electric wire. US 3 680 753 discloses a filament feeding system for the protection of plastic products. US 3 680 753 suggests the employment of a pneumatic device in order to maintain a constant tension in the filament feeding system. The disclosed filament feeding system does not pay-out a tension sensitive material with spiral grooves and does not rotate synchronously with the turning of the spiral grooves. From EP-A-0 316 798 an apparatus for inserting optical fibres into spiral grooves provided in a spacer to produce a spacer type optical fibre cable is known. As may be seen from Figures 1 and 5 of this document, the spacer is drawn out from the supply bobbin by means of a drawing capstan. The apparatus suggested in EP-A-0 316 798 corresponds to the prior art already discussed in respect to Figure 3. In view of the prior art it is the object of the present invention to provide a method and an apparatus for accurately controlling the tension of paid-out linear material wherein the apparatus may be constructed with a shorter overall length. This object is solved by the subject matter of claims 1 and 4. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a linear material paying-out apparatus embodying the principles of the present invention; FIG. 2 (Prior Art) is a perspective view of a slot rod as a linear material; and FIG. 3 (Prior Art) is a schematic view of a conventional linear material paying-out apparatus. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a linear material paying-out apparatus 10 according to the invention. The apparatus 10 includes a reel 21 having a slot rod 11 wound thereabout. The rod 11 is the linear material to be pay out. The apparatus includes a frame 22, a rotary shaft 23 for supporting the reel at one end of the frame so as to pay out the rod in a direction perpendicular to the axis of the shaft, a disk 24 fastened to the frame, a pair of rollers 25 for supporting the disk, and a support member 26 for supporting the frame. The frame 22 can be rotated about the direction that the rod 11 is sent-out, synchronously with the turning of the spiral grooves 14 thereof, by a driver (not shown). The apparatus 10 includes a capstan assembly 34 on which rod 11, to be pay out, is wound and supported. The capstan assembly 34 keeps the paying-out speed of the rod constant. The capstan assembly 34 includes a pair of axially spaced capstan wheels 27 and 28 being rotatably supported by the frame 22. A drive motor 29 is connected to the capstan wheel 28. The apparatus 10 further includes a dancer member 35 for applying a prescribed tensile force to the rod 11. The dancer member 35 includes a dancer wheel 30 rotatably supported near the capstan wheel 27 and movable within a prescribed range toward and away from capstan wheel 27. An urging spring 31 is provided between the dancer wheel 30 and the frame 22 for urging the dancer wheel 30 within the prescribed range. A sensor (not shown) is attached to the frame 22 in order to detect the position of the dancer wheel 30 within the prescribed range. The sensor is connected to a controller (not shown) provided to control the motor 29 for driving the capstan wheel 28. The apparatus 10 further includes guide rollers 32 and 33 for guiding the rod 11 while it is being pay out. The slot rod 11 is pay out by the apparatus 10 while being unwound from the reel 21, guided by the guide rollers 32 and 33 and engaged on the capstan wheels 28 and 27 and the dancer wheel 30. At that time, the rod 11 is moved forth by the capstan wheel 28 being rotated by the motor 29. A prescribed tensile force is applied to the rod 11 through the action of the urging spring 31 as the rod passes on the dancer wheel 30. At that time, the dancer wheel 30 is held in a predetermined position within the prescribed range due to the balance between the urging force of the urging spring 31 and the tension of rod 11. The position of the dancer wheel 30 is detected by the sensor. The motor 29 is controlled by the controller depending on the result of the sensed detection, to regulate the rotational speed of the capstan wheel 28 in order to keep the tension of the rod 11 within a desired value. The tension of such a slot rod was actually measured while the rod was being pay out by the apparatus 10. The outside diameter of the rod 11, that of a tension-withstanding steel wire provided in the central portion of the body of the rod, and the send out speed of the rod were 10.5 mm, 1.6 mm, and 25 m/min, respectively. Portions of the rod were made of high-density polyethylene. TABLE 1 shows the measurement results of the invention compared with that of a conventional apparatus. Conventional Apparatus Apparatus 10 Tension (50 kg in target value) (50 ± 7) kg (50 ± 2) kg Entire machine length 15 m 11 m As evident from TABLE 1, the tension of the rod 11 is kept more stable with the apparatus 10 than with the conventional apparatus. In the linear material paying-out method and linear material paying-out apparatus which are provided in accordance with the present invention, the paying-out speed of a linear material unwound from a reel is restricted and controlled by the capstan assembly 34. A prescribed tensile force, which can be accurately controlled, is applied to the material by a dancer member 35 to stabilize the tension of the material. For that reason, a high quality optical fiber cable, for example, can be manufactured from such a linear material through the use of the method and the apparatus of the invention.

Claims: An apparatus for paying out a linear material having spiral grooves, which are to receive a ribbon optical fibre cable, comprising: a reel (21) having the linear material (11) wound thereon, said reel being arranged to be rotatable so as to pay-out the linear material therefrom along an axis, a frame (22) supporting said reel, said apparatus being arranged so that said frame is only rotatable about a central axis thereof, said central axis being coaxial with the axis along which the material is paid out, a capstan assembly (34) supported on said frame, for restricting pay-out speed of said linear material, a dancer member (35) disposed downstream of said capstan assembly for applying a prescribed tensile force to said material, said dancer member being disposed between the reel and the capstan assembly, means for detecting the position of said dancer member, said capstan assembly controlling said pay-out speed so as to keep said detected position unchanged, means (24) arranged to rotate said frame about an axis of which the material is paid out, at a speed synchronous to the turning of said spiral grooves, and means for inserting said optical fibre ribbon into a groove of said linear material. An apparatus according to claim 1, wherein said capstan assembly (34) includes a pair of axially spaced, rotatably supported wheels (27, 28). An apparatus according to claim 1, wherein said dancer member (35) includes a rotatably supported wheel (30) and a spring (31) fixed between said frame and said wheel, said wheel being urged by said spring within a prescribed range toward and away from said capstan assembly. A method of paying out linear material having spiral grooves which are to receive a ribbon optical fibre cable and which is wound on a reel supported by a frame arranged to be only rotatable about a central axis thereof, the method comprising the steps of: rotating said reel (21) to unwind the material (11) therefrom along an axis; directing the material to a capstan assembly (34) supported on said frame; restricting the pay-out speed of the material with said capstan assembly; directing the material to a dancer member (35), said dancer member being disposed down stream of said capstan assembly, and being disposed between the reel and the capstan; applying a prescribed tensile force to the material by use of said dancer member; detecting a position of said dancer member; controlling said pay-out speed by said capstan assembly to keep said detected position unchanged; rotating said frame about the axis of which the material is paid out, synchronous to the turning of said spiral grooves; and inserting said optical fibre ribbon into a groove of the linear material. The method according to claim 4, wherein the step of applying a prescribed tensile force includes one of moving said dancer member toward and away from said capstan assembly in a direction parallel to the rotation axis of said frame.

Inventors: ITO YASUSHI, OGAWA SATOSHI, ITO,YASUSHI, OGAWA, SATOSHI, Ito,Yasushi, c/o Yokohama Works, OGAWA, SATOSHI,C/O YOKOHAMA WORKS
Applicants: SUMITOMO ELECTRIC INDUSTRIES, SUMITOMO ELECTRIC INDUSTRIES, LIMITED
Application year: 1992
Main classification: G02B6
IPC codes: D07B7, G02B6, B65H51, B65H59