GB2056516A - Filament packaging - Google Patents

Abstract

A length of filamentary material, such as wire or optical fibre, is packaged in the form of a loose coil wound free from tension in an annular channel defined by the perimeter wall of a circular pan and an inner wall formed by a projection from the bottom of the pan, the pan having a tightly fitting lid. For forming the package, the pan is disposed horizontally and the filament is fed continuously downwardly into the annular channel, either the pan or the feed means being rotated, and the linear speed of travel of the filament into the pan being maintained equal to the mean peripheral speed of the filament coil formed. If the pan is rotated while the feed means is maintained stationary, the filament deposited in the pan is free from twist. Two forms of apparatus for forming the package are described. <IMAGE>

Description

SPECIFICATION Filament packaging This invention relates to the packaging of lengths of filamentary material, such as wire or optical fibre, the object of the invention being the pro vision of a form of package, for one or more filament lengths, which is less bulky than the conventional reel type of package, is compact and convenient for transportation and storage, and provides full protection for the filament or filaments against exposure and damage.

The invention also relates to a method of, and apparatus for, carrying out the packaging.

According to the invention, a filament package consists of a circular pan having a circular inner wall projecting from the bottom thereof and defining an annular channel between the said inner wall and the perimeter wall of the pan, and one or more lengths of filament lying loosely coiled within the annular channel, each turn of the coil being loosely wound around the inner wall, so that the filament is substantially free from tension, the pan being substantially oniy of sufficient depth to accommodate said length or lengths of filament and being provided with a tightly fitting lid.

The invention is particularly advantageous for the packaging of optical fibres, since the substantial absence of tension in the packaged fibres assists in minimising optical losses in the fibres when they are subsequently employed for the transmission of signals in a communication system. Before being packaged in accordance with the invention, optical fibres are covered with a protective coating and/or jacket, of a type usually provided during the manufacture of an optical fibre, immediately after drawing of the fibre from a vitreous preform. Such covering may consist of a coating of synthetic resin, such as polyurethane resin, and/or extruded tubular jacket of, for example, amorphous nylon or meltprocessable polyester, which jacket may fit loosely around the fibre or may be filled with liquid or extruded over a buffering layer of a soft resin such as silicone resin.

The pan and lid may be formed of metal or any other suitable material, such as rubber, synthetic plastic material, wood or cardboard. If desired, especially for packaging optical fibres, the channel in which the filament is accommodated may be provided with a soft protective surface lining, such as a layer of plastic foam or felt, and if necessary the filament coil may be covered with padding of similar material to minimise movement of the turns of the filament in the channel during transit. The lid of the pan may be sealed in position to prevent the penetration of dust into the package. Any desired identification marks can readily be applied to the exterior of the package. The pan can, of course, be of any desired depth, depending upon the total length of the filament or filaments which it is required to contain.

In the method of forming the package, in accordance with the invention, the pan for receiving the filament is disposed horizontally and a length of filament is fed continuously downwardly through a channelled feed member into the said annular channel in the pan, while either the pan or the channelled feed member is rotated about a vertical axis so that the filament is loosely wound in the channel, the filament being fed into the channel at a linear speed which is equal to the mean peripheral speed, as hereinafter defined, of the filament coil so formed in a rotating pan, ortho the speed of travel of the filament outlet end of a rotating feed member.

The filament is thus coiled in loose, randomly disposed flat turns, all lying within the said channel.

The "mean peripheral speed" of the coil, referred to above, is the peripheral speed of travel imparted by the rotation of the pan to a turn of the coil which lies wholly on a circle the diameter of which is equal to the mean diameter (dm) ofthe channel as defined by the formula

where d1 is the inner diameter of the peripheral wall ofthe pan and d2 is the outer diameter ofthe inner wall defining the channel. The maintenance of equality between the linear speed of travel of the filament and the mean peripheral speed of the coil, or the speed of travel of the outlet end of the feed member, as the case may be, ensures that the filament is loosely coiled and is therefore free from tension: when a filament is unwound from a reel to be fed into the pan, any winding tension in the filament on the reel will be relieved.

If the package includes a plurality of filament lengths, these are usually introduced into the channel consecutively.

Afirstform ofapparatusforforming a package in accordance with the invention, by the method described above, includes a horizontal support for a filament-receiving pan, rotatable about a central vertical axis, a filament driving wheel disposed vertically, rotatable about its horizontal axis, and positioned to receive the filament on the perimeter of the wheel and to propel the filament continuously towards the said channel in the rotating pan on said support, an inclined channelled filament feed member, located in a fixed position, for conveying the filament from the driving wheel into the said channel in the pan, driving means for causing rotation of the pan support and the filament driving wheel, each at a predetermined rate such that the peripheral speed of the wheel is equal to the mean peripheral speed of the filament coil formed in the pan channel, and means for controlling the linear speed of travel of the filament down the said channelled feed member, such that the said linear speed is equal to the peripheral speed of the wheel.

The channelled filament feed member employed in the above-described form of apparatus may be a tube, or a chute in the form of a trough of sufficient width to accommodate the filament loosely.

A second form of apparatus for forming a package in accordance with the invention by the aforesaid method includes a non-rotatable horizontal support for a filament-receiving pan, a filament driving wheel disposed vertically, rotatable about its horizontal axis, and positioned to receive the filament on the perimeter of the wheel and to propel the filament continuously towards the pan, a filament feed tube for conveying the filament from the driving wheel into the said channel, which tube is located above the pan, is rotatable about a vertical axis aligned with the vertical axis ofthe pan, and is so shaped that the filament outlet end of the tube lies above the said channel and is caused, by such rotation ofthe tube, to travel along a circular path above the channel, while the pan is held stationary, driving means for causing rotation of the filament driving wheel and the filament feed tube, each at a predetermined rate such that the peripheral speed of the wheel is equal to the speed oftravel of the outlet end of the feed tube along said circular path, and means for controlling the linear speed of travel of the filament through the said feed tube, such that said linear speed is equal to the peripheral speed ofthe wheel.

When the first form of apparatus is employed, since the filament is fed in a straight line from a stationary feed member, into the channel in the rotating pan, the coiled filament deposited in the pan is free from twist. On the other hand, when the second form of apparatus is employed, twist is introduced into the filament as it is spun into the stationary pan from the rotating feed tube outlet; however, this twist can readily be eliminated subsequently on withdrawal of the coiled filament from the pan by unwinding.

Preferably, in either of the above-described forms of apparatus, the diameter of the filament driving wheel is equal to the mean diameter, as defined above, of the filament-receiving channel in the pan, which corresponds to the mean diameter of the coil deposited in the pan, and the driving means is arranged to rotate the wheel and either the pan support, or the outlet end of the filament feed tube, in the first and second forms of apparatus respectively, at the same rate, this being the simplest arrange mentforensuringthatthe peripheral speed ofthe wheel is maintained equal to the mean peripheral speed of the coil, or the speed of travel of the feed tube outlet If desired, however, the wheel diameter may be smaller or largerthan the mean coil diameter, the relative rates of rotation of the wheel and the pan support orfilament feed tube being suitably adjusted: thus if the wheel diameter is less than the mean coil diameter, the rate of rotation ofthe wheel must be greater than that of the pan support or fila mentfeed tube outlet, and if the wheel diameter is greaterthanthe mean coil diameter the rate of rotation of the wheel must be less than that of the pan support or filament feed tube outlet, in order that the peripheral speed of the wheel shall be equal to the mean peripheral speed of the coil or the speed of the feed tube outlet, as the case may be.

The speed of travel of the filament along the feed member can be controlled, in either form of apparatus, by means of a device which presses the filament against the surface of a part of the driving wheel perimeter; a suitable device, for example, is a pulley formed of relatively soft resilient material, such as rubber, arranged to bear against the wheel perimeter under a small load, art a point adjacent to the feed member, or a drive belt arranged to contact a portion of the wheel perimeter and thus press the filament against the wheel.

Means may be provided for guiding the filament into a desired position on the perimeter ofthe driv ing wheel: such means may suitably consist of a pair of vertically disposed rollers, between which the filament is arranged to pass, or a small pulley with a central peripheral groove in which the filament is a sliding fit, the pulley being positioned in contact with the driving wheel, with the groove adjacent to the centre of the perimeter of the wheel.

When a filament is unwound from a reel to be passed to eitherofthe above forms of apparatus for coiling it in a pan, the rotatable parts ofthe apparatus will usually be rotated ata constant speed. However, the filament may be fedto the coiling apparatus directly from a manufacturing line, and in this case arrangements may be provided for varying the speeds of rotation of the rotatable components in synchronism with accelerations and decelerations in the manufacturing line.

The turns ofthe filament coil may have a tendency to fall partially outside the annular channel as they are fed into the pan: such a tendency may result from disturbances in the ambient atmosphere, or from electrostatic repulsion between the turns of the coil. In orderto prevent such misplacementofthe filament turns, it is desirable to provide an arrangement for retaining the turns in the channel, a suitable arrangement consisting of two concentric cylinders, preferably of metal, which are placed in the channel, at its outer and inner edges, and which effectively extend the channel walls vertically. The cylinders are removed after the whole length of filament has been deposited in the channel.

One advantage of the filament package of the invention is that it provides for easy withdrawal of the filament from the package by a simple unwinding procedure, which can be carried out by apparatus similar to that used for forming the package, as described above, with the directions of rotation of the rotatable components reversed. Thus the filament is pulled from the pan channel, up the chute or other suitable conveyor, and round the driving wheel, whence it can be wound on to a reel if required or, in the case of a length of optical fibre, can be fed directly to a cable-making machine for incorporation in the cable, the unwinding speed being adjusted as required to be compatible with other operations involved in the production of the cable; During the unwinding procedure, the inertia of the system will be low, enabling rapid acceleration and deceleration to be obtained. The tension introduced into the filament during unwinding will be low, being only that equivalent to the weight of the filament being withdrawn, together with a small acceleration tension.

An additional advantage of the package of the invention, when it is employed for one or more optical fibres, is that the fibre can be tested while in the pan, and hence while free from tension.

Some specific forms of apparatus forthe production of an optical fibre package in accordance with the invention, and the methods of operation of such apparatus, will now be described by way of example with reference to the accompanying schematic draw ings, in which: Figure 1 shows one form of apparatus in elevation, Figure 2 shows, in side elevation, a modification of part ofthe apparatus of Figure 1, Figure 3 shows a feature of Figure 2 in front elevation, and Figure 4 shows a second form of apparatus in elevation.

Like parts in the different figures of the drawings are indicated by the same reference numerals.

The apparatus shown in Figure 1 comprises a circular horizontal turntable 1 for supporting a fibrereceiving pan 2, and an arrangement for coiling an optical fibre 3 in the pan which consists of a vertical fibre driving wheel 4, a drive belt 5 passing round a pair of pulleys 6, 7, by which the belt is held in contact with the perimeter of the wheel 4, for controlling the linear speed of travel of the fibre as it leaves the wheel, and a feed tube 8 along which the fibre passes from the wheel into the pan 2. The interior of the pan 2 is formed with a circular upstanding projection 9, defining an annular channel 10 in which the fibre is deposited.Two concentric cylinders 11, 12 are inserted into the pan 2, within the channel 10, to provide increased height of the walls defining the channel and thus ensure that the fibre turns are wholly retained in the channel throughout the coiling process. The diameter of the driving wheel 4 is equal to the mean diameter of the coil of fibre deposited in the channel.

The pan turntable 1 is mounted on a vertical shaft 13 on which is also mounted a ridged wheel 14, for effecting rotation of the turntable and pan. The wheel 4 is mounted on a horizontal axle connected to a bevel gear 15 having a right angle drive with a 1:1 ratio, the gear being driven by rotation of the shaft 16 and ridged wheel 17, to cause the wheel 4 to rotate about its axle. The ridged wheels 14 and 17 are rotated by co-operation with a toothed belt 18 which is driven by an electric motor 19 through ridged wheel 20.The ridged wheels 14 and 17 are of the same diameter: this arrangement, in conjunction with the 1:1 gear ratio of the driving mechanism for the wheel 4, ensures that the rates of rotation of the wheel 4 and pan 2 are equal, irrespective ofthe diameter of the ridged wheel 20 driven by the motor, and hence that the peripheral speed of the wheel 4 is equal to the mean peripheral speed ofthe fibre coil deposited in the pan.

The fibre is fed to the wheel 4 over a guide wheel 21 and tension controlling wheel 22, and may be passed to the wheel 21 either from a reel on which it has previously been wound, or directly from the fibre drawing and coating and/orjacketing line.

The operation of the apparatus is controlled by conventional means housed in a control box 23, which includes appropriate switches. The whole apparatus is supported on a suitable framework 24.

The modification shown in Figure 2 is an alternative arrangement for guiding and controlling the speed of travel of the fibre on the driving wheel 4, which arrangement can be substituted for the belt 5 and pulleys 6,7 of Figure 1. The arrangement consists of a guide pulley 25 for guiding the fibre on to the centre of the perimeter of the wheel 4, and a rubber pulley 26 arranged to cooperate with the wheel 4 for controlling the linear speed ofthe fibre.

As shown in Figure 3, the pulley 25 has a V-shaped groove 27 in the centre of its periphery by means of which the fibre is guided on to the centre of the periphery ofthe wheel 4. The pulley 26 is arranged to bear upon the perimeter surface of the wheel 4 under a light load, applied by conventional spring or gravity means (not shown in the drawing), so that as the fibre passes beneath the pulley it is restrained sufficiently to attain a linear speed equal to the peripheral speed of the wheel 4, just before the fibre leaves the wheel to enter the tube 8.

If desired, a guide pulley similar to the pulley 25 of Figures 2 and 3 may be incorporated in the apparatus shown in Figure 1, in addition to the contact belt 5 and pulleys 6 and 7.

In a specific example of the production of an optical fibre package by the method and apparatus described above with reference to the drawings, either as shown in Figure 1 or with the modification of Figures 2 and 3, the inner diameter of the peripheral wall of the pan 2 is 38.5 cm, the channel 10 is 3.5 cm wide, and the depth of the pan is 2.0 cm: this pan will contain a 5 km length of resin-coated optical fibre 150 microns in diameter, coiled in the channel. The diameter of the wheel 4 is 35.2 cm, and both the wheel 4 and the pan 2 are rotated at a rate of 45 rpm, the linear speed of travel of the fibre into the pan, the peripheral speed of the wheel 4, and the mean peripheral speed of the fibre coil all being 49.5 metres per minute. The feed tube 8 suitably has a bore not greater than 10 mm diameter.

In the apparatus shown in Figure 4, the fibrereceiving pan 2 is non-rotatably mounted on a support 30. The apparatus includes a fibre driving wheel 4, a guide wheel 21 and a tension controlling wheel 22, respectively similar to those described with reference to Figure 1, the diameter ofthe wheel 4 being equal to the mean diameter ofthe channel 10 in the pan 2. The wheel 4 is driven by gear means similar to that described with reference to Figure 1, actuated by rotation of the vertical shaft 16 and ridged wheel 17, the latter being rotated byco- operation with the toothed belt 18, driven by the motor 19.The arrangement for guiding the optical fibre 3 on the driving wheel 4, and for controlling the speed of travel of the fibre, is similar to that described above with reference to Figures 2 and 3, consisting of a grooved pulley 25 for guiding the fibre on to the centre of the perimeter of the wheel 4, and a rubber pulley 26 bearing upon the perimeter surface of the wheel 4 under a slight load, so as to ensure that the linear speed of the fibre as it leaves the wheel 4 is equal to the peripheral speed of the wheel. The fibre passes from the wheel 4through a feed tube 31,32, and thence into the pan channel 10.

The fibre feed tube consists of an upper, straight portion 31, which is disposed vertically with its axis above and in alignment with the vertical axis of the pan 2, and a lower portion 32 which is bent to form a halfturn of a helix sloping outwards from the central position of the portion 31, so that the fibre outlet end 33 of the tube is located above the central region of the channel 10. The tube is supported in bearings 34, 35, and passes through and is secured to a ridged wheel 36, of the same diameter as the wheel 17, located between the bearings. The belt 18 lies in contact with the wheel 36, so that in operation of the apparatus the wheel 36 and the tube 31,32 are rotated by the action of the belt, in synchronism with the rotation of the driving wheel 4 about its horizontal axis. As the tube rotates, the lower end 33 thereof travels along a circular path above the channel 10, so that the fibre emerging from the lower end of the tube is laid in the channel in a succession of circular turns of diameter equal to that of the wheel 4.

The dimensions of the pan 2 and driving wheel 4, in the apparatus shown in Figure 4, are suitably the same as those described in the above specific example with reference to Figure 1, and the wheel 4 and feed tube 31, 32 may be rotated at a rate of 45 rpm, giving a linear speed of travel of the fibre into the pan of 49.5 metres per minute.

Claims (12)

1. A filament package consisting of a circular pan having a circular inner wall projecting from the bottom thereof and defining an annular channel between the said inner wall and the perimeter wall of the pan, and one or more lengths of filament lying loosely coiled within the annular channel, each turn of the coil being loosely wound around the inner wail, so that the filament is substantially free from tension, the pan being substantially only of sufficient depth to accommodate said length or lengths of filament and being provided with a tightly fitting lid.

2. A method of forming a filament package according to Claim 1, wherein a said pan is disposed horizontally and a length of filament is fed continu ously downwardlythrough a channelled feed member into the said annular channel in the pan, while eitherthe pan or the channelled feed member is rotated about a vertical axis so that the filament is loosely wound in the channel, the filament being fed into the channel at a linear speed which is equal to the mean peripheral speed, as herein before defined, ofthe filament coil so formed in a rotating pan, orto the speed of travel of the filament outlet end of a rotating feed member.

3. Apparatus for forming a filament package by a method according to Claim 2, which includes a horizontal support for a filament-receiving pan, rotatable about a central vertical axis, a filament driving wheel disposed vertically, rotatable about its horizontal axis, and positioned to receive the filament on the perimeter of the wheel and to propel the filament continuouslytowardsthe said channel in the rotat ing pan on said support, an inclined channelled fila ment feed member, located in a fixed position, for conveying the filament from the driving wheel into the said channel in the pan, driving means for caus ing rotation of the pan support and the filament driv ing wheel, each at a predetermined rate such that the peripheral speed of the wheel is equal to the mean peripheral speed of the filament coil formed in the pan channel, and means for controlling the linear speed of travel of the filament down said channelled feed member, such that said linear speed is equal to the peripheral speed of the wheel.

4. Apparatus according to Claim 3, wherein the diameter of the filament driving wheel is equal to the mean diameter, as hereinbefore defined, ofthe filament-receiving channel in the pan, and the driving means is arranged to rotate the wheel and the pan support at the same rate.

5. Apparatus for forming a filament package by a method according to Claim 2, which includes a nonrotatable horizontal support for a filament-receiving pan, a filament driving wheel disposed vertically, rotatable about its horizontal axis, and positioned to receive the filament on the perimeter of the wheel and to propel the filament continuously towards the pan, a filament feed tube for conveying the filament from the driving wheel into the channel in the pan, which tube is located above the pan, is rotatable about a vertical axis aligned with the vertical axis of the pan, and is so shaped that the filament outlet end of the tube lies above the said channeland is caused, by such rotation of the tube, to travel along a circular path above the channel, while the pan is held stationary, driving means for causing rotation of the filament driving wheel and the filament feed tube, each ata predetermined rate suchthatthe peripheral speed of the wheel is equal to the speed of travel of the outlet end of the feed tube along said circular path, and means for controlling the linear speed of travel of the filament through the said feed tube, such that said linear speed is equal to the peripheral speed of the wheel.

6. Apparatus according to Claim 5, wherein the diameter of the filament driving wheel is equal to the mean diameter, as hereinbefore defined, ofthe filament-receiving channel in the pan, and the driving means is arranged to rotate the wheel and the outlet end of the filament feed tube at the same rate.

7. Apparatus according to any of the preceding Claims 3, 4, 5 or 6, wherein the said means for controlling the linear speed oftravel of the filament through the said feed member consists of a device which presses the filament against the surface of a part of the driving wheel perimeter.

8. Apparatus according to any of the preceding Claims 3 to 7, which includes means for guiding the filament into a desired position on the perimeter of the driving wheel.

9. Apparatus according to any of the preceding Claims 3 to 8, which includes two concentric cylinders, placed in the said channel in the pan at the outer and inner edges thereof, for effectively extending the channel walls vertically during the deposition of the filament in the channel.

10. Apparatus for the production of an optical fibre package by a method according to Claim 2, substantially as shown in, and as hereinbefore described with reference to, Figure 1, or Figures 2 and 3, or Figure 4 of the accompanying drawings.

11. A method according to Claim 2, forthe production of an optical fibre package, substantially as hereinbefore described by way of example with reference to Figure 1, or Figures 2 and 3, or Figure 4 ofthe accompanying drawings.

12. An optical fibre package formed by the method according to Claim 11.