Title of Invention

AN OPTICAL FIBRE SPOOL AND A COVER THEREOF

Abstract

The invention relates to an optical fibre spool (10) comprising a barrel (11) around which the optical fibre is wound. The barrel (11) is covered with a pad (12) of a predetermined thickness (t) for protecting the optical fibre from impacts. A first annular flange (13) is positioned at a first end of the barrel (11) and a second annular flange (13) is positioned at an opposite end of the barrel (11) for supporting the barrel (11). An optical fibre drawing slot (13a) is provided on the first annular flange (13) through which an end portion of a wound optical fibre is drawn. The optical fibre drawing slot (13a) is positioned so in the upper surface (13b) of the slot (13a) is spaced from the inner circumference (11a) of the first annular flange (13) by a distance equal to at least twice the predetermined thickness of the pad (12). The invention also provides a cover (20) for the optical fibre spool (10) comprising inter—engaging cover portions (21).

Full Text

-lA- BACKGROUND TO THE INVENTION The present invention relates to an optical fibre spool and a spool cover for use in storing and transporting an optical fibre. Optical fibres are used in communications networks for the rapid transmission of information. In recent years, there has been a drastic increase in demand for optical fibres. Optical fibres generally come in two forms. They may form part of an optical fibre cable. In an optical fibre cable, the optical fibres are housed within a cylindrical tube. Multiple layers of protective material are also provided in the tube, which surround the optical fibres. The multiple protective layers prevent damage to the optical fibres and help ensure that the optical fibres retain their optical and mechanical characteristics. Alternatively, the optical fibres themselves may be supplied. In this case, the optical fibres are typically wrapped around a spool to help prevent damage to the optical fibres. FIG. 1 is a perspective view of a conventional optical fibre spool 100. The conventional optical fibre spool 100 is designed to hold a short optical fibre, i.e an optical fibre about 15-20 km long. As shown in FIG. 1, the spool 100 includes a cylindrical barrel 110 around which an optical fibre is wound. It also includes two flanges 130 positioned at the ends of the barrel 110. The spool 100 is relatively easy to handle because the diameter of the barrel 110 differs from that of the flanges 130 by only a small amount, e. g about 83-88 mm. Additionally, the optical fibre would around the spool 100 is usually lightweight. The conventional spool 100 also includes a pad 120, an optical fibre drawing slot 130a and an auxiliary winding 2 portion 150. The pad 120 covers the cylindrical barrel 110 and helps prevent damage to a wound optical fibre caused by impact. The auxiliary winding portion 150 is provided on a flange 130 for retaining the end portion of an optical fibre. Specifically, the end portion of a wound optical fibre is drawn through the slot 130a and is then wound around the auxiliary winding portion 150. Recently, however, there has been increasing demand for long optical fibres. Unfortunately, the conventional spool cannot adequately hold a long optical fibre. if a long optical fibre is wound around the spool, the end portions of the flanges become warped. This in turn causes the optical fibre to collapse. Additionally, serious deformation of the spool may result at certain temperatures because of the increased weight of the optical fibre. Moreover, the spool becomes difficult to handle. Additional problems are caused by the optical fibre drawing slot 130a and pad 120. As shown in FIG, 2, the difference in height between the optical fibre drawing slot 130a and pad 120 is very small. Specifically, the thickness of the pad 120 is almost the same as the height of the slot 130a, leaving very little space through which to draw an optical fibre. Thus, when the optical fibre is drawn through the slot 130a from the shock-absorbing sponge pad 120, the optical fibre may become caught between the pad 120 and an inner side surface of a flange 130. Additionally, the optical fibre may be forced around the auxiliary winding portion 150. Either situation causes bending of the optical fibre, which is a cause of optical fibre failures. The above-described problems can be summarised as follows: (1) it is difficult to wind a long optical fibre around a conventional spool because the spool is designed for an optical fibre 15-20 km in length; 3 (2) Winding of a long optical fibre around the conventional spool causes the flanges of the spool to become warped; the spool may also become seriously deformed at certain temperatures when a long optical fibre is wound around it; (3) the small difference in height between the optical fibre drawing slot and the pad causes bending of the optical fibre, which can cause failure; additionally, bending means that the optical fibre is non-linear, which in turn means it is difficult to calculate an accurate loss value; and (4) winding of a long optical fibre cround the spool increases the weight of the spool, thereby causing difficulty in transporting and storing the spool; this in turn means it becomes difficult to protect the optical and mechanical characteristics of the optical fibre from the external environment. The following patents each disclose features in common with the present invention but do not teach or suggest the specifically recited optical fiber spool and spool cover of the present invention U.S. Patent No,3,650,388 to Osojnak, entitled Tape Canister, U.S. Patent No,1,488,322 to Doty, entitled Film Reel Cover, U.S. Patent No, 1,702,242 to Bureau, entitled Reel, U.S. Patent No. 4,635, 789 to Webb, entitled Locking Mechanism For Magnetic Tape, U.S.Patent No, 4,974,789 to Milburn, entitled Dispensing Package For a Fiber-Optic Device, U.S. Patent No. 5,702,066 to Hurst et al., entitled Optical Fiber Spool and Method of Loading Spool, U.S. Patent No.1,981,139 to Bureau, entitled Reel, U. S. Patent No. 3,391,879 to Le Bus Sr., entitled Non-Crushing Multi-Layer Cable Spooling Method And Apparatus Therefor, and U S Patent No. 2,741,441 to Le Bus Sr., entitled Method And Apparatus Of Cross-Over Cable Spooling. 3A SUMMARY OF THE INVENTION Accordingly, an objective of the present invention is to overcome the problems outlined above. The present invention thus provides an optical fibre spool for storing and transporting an optical fibre comprising a barrel around which the optical fibre is wound, the barrel being covered with a pad of a predetermined thickness for protecting the optical fibre from impacts; a first annular flange positioned at a first end of the barrel and a second annular flange positioned at an opposite end of the barrel and a second annular flange positioned at an opposite end of the barrel for supporting the barrel; an optical fibre drawings slot provided on the first annular flange through which an end portion of a wound optical fibre may be drawn. The upper surface of the optical fibre drawing a slot being spaced from the inner circumference of the barrel by a distance which is substantially equal to, or greater than, twice the thickness of the pad. 4 Such an optical fibre spool prevents bending of an optical fibre and thus reduces the chance of optical fibre failure. Preferably, the said distance is substantially equal to twice the thickness of the pad. It is also preferred that the optical fibre spool further comprises auxiliary winding means provided on the first annular flange around which the portion of an optical fibre that is drawn through the optical fibre drawing slot may be wound. One or more blades may be positioned on the outer surfaces of the first and/or second annular flanges for supporting a wound optical fibre. Preferably, the thickness of the blade or blades is approximately 3 mm to prevent warping of the spool. It is preferred that the outer diameter of the first annular flange and that of the second annular flange are each greater than the diameter of the barrel by a distance approximately equal to 95-100 mm so that an optical fibre at least 30 km long can be wound around the spool. The present invention also provides an optical fibre spool cover for storing and protecting an optical fibre spool comprising first and second inter-engaging cover portions, each cover portion comprising: a semi-circular body for covering the spool; semi-circular guide means provided at opposite edges of the semi-circular body for retaining flanges of a spool; a handle provided at one end of the semi-circular body for facilitating transport of the spool cover and spool; and engaging means provided at the opposite end of the semi-circular body for engaging cooperating engaging means provided on the other cover portion. 5 For structural simplicity, the engaging means may comprise a hook and a cooperating recess. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The present invention will now be described by way of example with reference to the accompanying drawings in which: FIG. 1 is a perspective view of a conventional optical fibre spool; FIG. 2 is a frontal view of an optical fibre drawing slot in the conventional optical fibre spool; FIG. 3 is a perspective view of an optical fibre spool according to a preferred embodiment of the present invention; FIG. 4 is a frontal view of an optical fibre drawing slot in the optical fibre spool according to the preferred embodiment of the present invention; and FIG. 5 is a perspective view of an optical fibre spool cover according to the present invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 3 is a perspective view of an optical fibre spool 10 according to a preferred embodiment of the present invention. As illustrated in FIG. 3, the optical fibre spool 10 includes a barrel 11 around which an optical fibre is wound. A sponge pad 12, indicated by the dotted lines, covers the barrel 11. The sponge pad 12 is shock-absorbing and prevents damage to an optical fibre resulting from impact. Flanges 13 are provided at the ends of the barrel 11 for supporting the barrel 11. Blades 14, fixed to the flanges 13, are provided for supporting a wound optical fibre. An auxiliary winding portion 15 is positioned on the outer surface of a flange 13, around which the beginning portion of the optical fibre is wound. An optical fibre drawing slot 13a is positioned on the same flange 13 on which the auxiliary winding portion 15 is located. The optical fibre drawing slot 13 is spaced from 6 the inner circumference 11a of the flange 13 by a predetermined distance. Specifically, the upper surface of the slot 13a is preferably spaced from the inner circumference 11a of the flange 13 by a distance 2t, when the thickness of the pad 12 is t. In a preferred embodiment, the components of the optical fibre spool are formed integrally by injection moulding. Additionally, in a preferred embodiment, the diameter of the barrel 11 is smaller than that of the flanges 13 by approximately 95-100 mm so that the spool 10 can hold an optical fibre at least 30 km long. The thickness of the blades 14 is also preferably increased to 3 mm. Increased blade thickness prevents the edge of the flanges 13 from being warped. Warping is caused by an increase in stresses in the central direction of the wound optical fibre, which in turn is caused by the increased weight of a long optical fibre. According,a longer optical fibre can be wound around the spool by making the blades 14 thicker. As shown in FIG. 4, the optical fibre drawing slot 13a is provided for drawing the optical fibre around the auxiliary winding portion 15. In particular, the optical fibre is preferably drawn through the slot 13a and then wound around the auxiliary winding portion 15. As illustrated, the slot 13a is spaced apart from the inner circumference 11 of the flange 13 by a predetermined distance. The predetermined distance is such that the slot 13a is positioned closer to the outer circumference of the flange 13 than slots in conventional spools. Specifically, as described above, assuming that the thickness of the pad 12 is t, the distance between the inner circumference 11a of the flange 13 and the upper surface 13b of the slot 13a is preferably 2t. This spacing takes into account the diameter of the optical fibre, since the thickness t of the pad 12 is only half the distance 2t between the inner circumference 11a of the flange 13 and the upper surface 13b of the slot 13a. 7 FIG. 5 is a perspective view of an optical fibre spool cover according to the present invention. As illustrated in FIG. 5, an optical fibre spool cover 20 includes a semicircular cover portion 21 and spool guides 21a, at opposite edges of the cover portion 21. A handle 22 is provided at one side of the cover portion 21, for use in transporting the optical fibre spool. At least one hook 23 and at least one catching portion 24 are provided at the other side of the cover portion 21. If a plurality of hooks 23 are provided, as illustrated in FIG. 5, they are positioned so that one catching portion 24 is placed between each pair of hooks 23. In a preferred embodiment of the present invention, two such spool covers 20 are connected to each other, with the hooks 23 of one cover engaging the catching portions 24 of the other cover and vice-versa. With such an arrangement, the spool is retained between the two covers 20. The cover portions 21 cover the optical fibre and the spool guides 21a hold the flanges of the spool. Thus, the optical fibre is prevented from being bent by stress or tension. The optical fibre is also protected from external impacts while it is being stored. Moreover, the handle 22 facilitates storage and transportation of the spool which is heavier because of having a long optical fibre wound around it. The two spool covers 20 are formed by moulding. They are assembled so that the portion 21 of one cover faces the portion 21 of the other cover. The covers are fixed to each other when alternatively arranged hooks 23 and catching portions 24 of one spool cover catch the corresponding catching portions 24 and hooks 23 of the other spool cover. Thus, the optical fibre spool and spool cover of the present invention have several advantages over conventional ones. The spool of the present invention can store an optical fibre at least 30 km long while the conventional optical fibre spool can only store an optical fibre that is 8 15-20 km long. Additionally, the optical fibre spool of the present invention is heavier than conventional spools spool and uses blades of increased thickness, which suppresses deformation of the spool. The spool of the present invention also prevents bending of an optical fibre by positioning the optical fibre drawing slot at a higher position. Furthermore, the spool cover of the present invention provides protection for the optical fibre spool. The spool cover also facilitates transport of the optical fibre spool, since it has a handle. 9 We Claim: 1. An optical fibre spool (10) for storing and transporting an optical fibre comprising: - a barrel (11) around which the optical fibre is wound, the barrel (11) being covered with a pad (12) of a predetermined thickness ( t) for protecting the optical fibre from impacts; - a first annular flange (13) positioned at a first end of the barrel (11) and a second annular flange (13) positioned at an opposite end of the barrel (11) and a second annular flange (13) positioned at an opposite end of the barrel (11) for supporting the barrel (11); - an optical fibre drawing slot ( 13a) provided on the first annular flange (13) through which an end portion of a wound optical fibre may be drawn, characterized in that the upper surface (13b) of the optical fibre drawing a slot (13a) being spaced from the inner circumference (11a) of the barrel (11) by a distance which is substantially equal to or greater than, twice the thickness (t) of the pad (12). 2. An optical fibre spool as claimed in claim 1, wherein said distance is substantially equal to twice the thickness (t) of the pad (12). 3. An optical fibre spool as claimed in claim l or claim 2, comprising auxiliary winding means (15) provided on the first annular flange (13) around which the portion of an optical fibre that is drawn through the optical fibre drawing slot (13a) may be wound. 4. An optical fibre spool as claimed in any one of claims 1-3, comprising at least one blade (14) positioned on the outer surfaces of one of the first and second annular flanges (13) for supporting a wound optical fibre. 5. An optical fibre spool as claimed in claim 4, wherein the thickness of said at least one blade (14) is substantially equal to 3mm. 10 6. An optical fibre spool as claimed in any one of claims 1-5, wherein the outer diameter of the first annular flange (13) and that of the second annular flange (13) are each greater than the diameter of the barrel (11) by a distance equal to 95-100mm. 7. A cover for optical fibre spool (10) for storing and protecting an optical fibre spool, comprising first and second inter-engaging cover portions (21), each cover portion (21) comprising: - a semicircular body (21) for covering the spool (10); - semi-circular guide means (21a) provided at opposite edges of the semi-circular body (21) for retaining flanges (13) of the spool (10); - a handle (22) provided at one end of the semi-circular body (21) for facilitating transport of the spool cover (20) and the spool (10); and - engaging means (23) provided at the opposite end of the semicircular body (21) for engaging a catching means (24) disposed on the other cover portion (20). 8. The cover (20) as claimed in claim 7, wherein the engaging means (23) comprise a hook and a cooperating recess. 9. An optical fibre spool for storing and transporting an optical fibre, the spool being substantially as described and illustrated herein with reference to Figs. 3 and 4 of the accompanying drawings. The invention relates to an optical fibre spool (10) comprising a barrel (11) around which the optical fibre is wound. The barrel (11) is covered with a pad (12) of a predetermined thickness (t) for protecting the optical fibre from impacts. A first annular flange (13) is positioned at a first end of the barrel (11) and a second annular flange (13) is positioned at an opposite end of the barrel (11) for supporting the barrel (11). An optical fibre drawing slot (13a) is provided on the first annular flange (13) through which an end portion of a wound optical fibre is drawn. The optical fibre drawing slot (13a) is positioned so in the upper surface (13b) of the slot (13a) is spaced from the inner circumference (11a) of the first annular flange (13) by a distance equal to at least twice the predetermined thickness of the pad (12). The invention also provides a cover (20) for the optical fibre spool (10) comprising inter—engaging cover portions (21).

Documents:

01039-cal-1998 abstract.pdf

01039-cal-1998 claims.pdf

01039-cal-1998 correspondence.pdf

01039-cal-1998 description(complete).pdf

01039-cal-1998 drawings.pdf

01039-cal-1998 form-1.pdf

01039-cal-1998 form-2.pdf

01039-cal-1998 form-3.pdf

01039-cal-1998 form-5.pdf

01039-cal-1998 pa.pdf

01039-cal-1998 priority document.pdf