WO1992015911A1

WO1992015911A1 - Fibre separator

Info

Publication number: WO1992015911A1
Application number: PCT/AU1992/000084
Authority: WO
Inventors: Allen James Conduit; Brian Murrihy; Edward Wilson
Original assignee: Fibernet Research Pty. Ltd.
Priority date: 1991-03-01
Filing date: 1992-02-28
Publication date: 1992-09-17
Also published as: AU1325292A

Abstract

A fibre optic separator has a housing (10) with input and output ports (11, 12). The input port (11) has one or more channels (31, 32) through which a fibre optic cable may enter the housing. The output port (12) has one or more passages (66-91) through which one or more optical fibres may exit the housing. Each channel/passage has an associated formation (35-38, 94-97) for retaining the protective casing, sheath, tube or the like which surrounds the optic cable/fibre, relative to the housing. The associated formation (35-38, 94-97) acts to relieve strain in the cable/fibre and may partly penetrate and/or frictionally or otherwise engage the protective casing, sheath, tube or the like.

Description

FIBRE SEPARATOR

The present invention pertains to fibre separators particularly optical fibre separators. More particularly the present invention pertains to separators for enabling bundles of fibres which may be encased in single tubes

(eg. multi-loose tube cable structures, multi slot cables,

Air Blown Fibre (ABF) units etc.) to be separated and routed as individually encased fibres or lower fibre count bundles. The fibre separator of the present invention may have application in management of optical fibres in cable breakout and termination.

Use of optical fibres for signal transmission is well known in the communications industry. While optical fibres present numerous advantages to conventional signal transmission, unique problems are associated with management of optical fibre transmission systems. For example, optical fibres having extremely small diameters are relatively delicate and require careful handling. This is particularly the case where relatively robust cables comprising bundles of fibres encased in tubes are required to be broken out or separated into groups for routing individually or in lower fibre count bundles to distributed locations. US Patent 4884862 to 3M Company discloses a fan out module for a similar purpose. However, the strain relief mechanism disclosed in the latter reference is only suitable for use with optical fibres which contain protective filaments such as aramid. Moreover, assembly of fibers to the 3M module is labour intensive because it requires separation of protective filaments from cables, placement of filaments and fibres in separate grooves formed in the module and bonding of the filaments in the grooves by means of adhesive such as epoxy resin to provide strain relief. Assembly of the 3M module requires considerable skill because cables are not positively retained in the module until adhesive is applied and because it is difficult to correct wrongly placed cables/fibres after the adhesive sets. Because the protective filaments are bonded in place the 3M module is not easily disassembled after installation. This reduces its flexibility because an installation must be reassembled from scratch and a fresh module fitted if rerouting or reorganization of cables is required after installation.

An object of the present invention is to provide a fibre separator which at least alleviates the disadvantages of the prior art.

A further object of the present invention is to provide a fibre separator which is capable of being mass produced in a manner which will offer relatively low manufacturing costs yet permit high performance in a finished product.

An object of a preferred form of the present invention to provide a fibre separator which may be constructed in modular form. The separator may include a plurality of components which may be field assembled into a variety of formats according to intended application.

This approach may reduce manufacturing costs and at the same time may provide a versatile and flexible separator which may be applied to a variety of optical fibre separating applications.

The fibre separator of the present invention may incorporate interchangeable components suitable for accommodating fibre retaining tubes having a large range of diameters eg. from 0.9 - 8.0 mm, depending on intended application. The interchangeable components may be retained in a housing having an input port for an input cable/fibre or cables/fibres and an output port for an output cable/fibre or cables/fibres. The or each input cable typically may comprise a bundle of fibres. The or each output cable typically may comprise individually encased fibres or lower count bundles of fibres.

The input port may include an inpμt cable/fibre anchor means and the output port may include an output cable/fibre anchor means. The input port typically may have a smaller cross-sectional area than the output port although the reverse may be the case in some applications. The housing includes a main cavity intermediate the input and output ports. The main cavity may be arranged to merge smoothly with the input and output ports. The main cavity may be substantially rectangular in cross-section in one form. The main cavity at one end may have a cross-sectional area which substantially matches the cross-sectional area of the input port and at its other end may have a cross-sectional area which substantially matches the cross-sectional area of the output port. The cross-sectional area of the main cavity intermediate the ends thereof may be intermediate the cross-sectional areas at its ends. In one form the main cavity may resemble a substantially trapezoidal wedge.

The main housing may be split longitudinally to assist assembly of a complete separator. In one form the housing may comprise a pair of identical half shells. The half shells may clip or snap fit together or they may be held together in any other suitable manner such as via screws or the like. The housing parts and input/output cable/fibre anchor means may be formed from any suitable material and by any suitable means. In one form the housing parts and input/output cable/fibre anchor means may comprise ABS plastics or similar material. The housing and anchor parts may be injection molded essentially by conventional means.

Each input/output anchor means may comprise an anchor block having a main body substantially in the form of a rectangular prism. The anchor means may be assembled with the housing such that it keys into the housing and is held against movement at least in the direction in which fibres/cables enter or exit the housing. Typically the anchor means may be held against movement in a longitudinal direction relative to the housing. The or each anchor means may include one or more projections suitable for keying into a corresponding recess or recesses in the housing. Each anchor means may include a pair of such keying projections. The or each keying projection preferably extends in a generally lateral direction relative to the longitudinal extent of the housing. The or each keying projection may be substantially semi-circular, rectangular, triangular or trapezoidal in cross-section. Alternatively the or each keying projection may comprise an entire lateral wall of the anchor means. The or each corresponding recess may be formed in the housing with or adjacent the input and/or output ports. The or each anchor means may- include one or more channels or passages. The or each channel/passage may be dimensioned to snugly receive a cable/fibre therein. The or each cable/fibre receiving channel or passage may be substantially semi-circular in cross-section but alternatively may be rectangular/square, V-section or triangular in cross-section. In some embodiments the or each channel or passage may be formed in a fitting extending from the main body of the anchor means. The fitting may be substantially annular in cross-section and may be formed coaxially with the or each channel or recess. The fitting may be adapted to fit into protective means such as a casing, sheath or tube associated with an optical cable.

The or each anchor means includes means for relieving strain in the or each cable/fibre. The strain relieving means may comprise one or more formations in walls of channels or passages formed in the main body of the anchor means. ' Alternatively the formations may be on walls of fittings extending from the main body of the anchor means. The strain relieving formations may comprise barb projections formed in opposed lateral walls of the or each cable/fibre receiving channel/passage or they may be formed on a wall or surface of a fitting extending from the main body. The or each strain relieving formation or projection may be adapted to at least partly penetrate and/or frictionally or otherwise engage the protective means such a casing, sheath, tube or the like which at least partly surrounds the or each cable/fibre. For example, the or each strain relieving formation may be adapted to at least partly deform the protective means in the region where the formation contacts the protective means and to key into the deformed region of the protective means. In some embodiments the or each strain relieving formation may at least partly penetrate the protective means. In one form the or each barb projection may penetrate substantially

40-50% but preferably not exceeding 90% of the depth of the casing, sheath or tube.

Each strain relieving formation may comprise a wedge shaped projection having a substantially triangular format in cross-section but may take other forms. The wedge shaped projection typically may extend substantially

0.1-0.15 mm from the wall of an associated cable/fibre receiving channel or passage and/or fitting extending from the main body. The projecting surfaces of the wedge may converge to a relatively sharp edge. The angle subtended by the converging surfaces may vary and in one form may be approximately 30°. The relatively sharp edge may be adapted to deform and/or cut into and penetrate the casing or sheath surrounding the or each cable/fibre. The relatively sharp edge preferably is oriented substantially normal to the longitudinal direction in which a cable/fibre is held in an associated cable/fibre receiving channel/passage and/or fitting which extends from the main body.

A plurality of strain relieving formations may be formed in walls of each cable/fibre receiving channel/passage or' a surface of a fitting extending from the main body. Opposing pairs of strain relieving formations may be formed in each cable/fibre receiving channel or passage or they may be staggered along the length of a channel/passage providing a labyrinth path. Strain relieving formations may be formed in an outer surface of each fitting extending from the main body. The formations may extend continuously or discontinuously around an outer perimeter of each fitting. Each cable/fibre anchor means may include a plurality of cable/fibre receiving channels/passages. The or each anchor means may be adapted to receive cables/fibres having the same or different diameters. Table 1 below shows examples of various numbers and sizes of cables which may be accommodated in an anchor means.

TABLE

In one form the main body of an anchor means associated with an input port of the housing may comprise a substantially rectangular block or prism approximately

18 mm wide, 15 mm long and 10 mm high and may include a single channel extending in its longitudinal direction and adapted to receive one cable approximately 8 mm diameter and containing, say, 12 fibres, or it may include a pair of channels adapted to receive a respective pair of cables each approximately 8 mm in diameter and containing, say, 3 fibres each. Alternatively, the or each channel may be formed at least partly within a respective fitting extending from the main body. Strain relieving formations as described herein may be provided in each cable/fibre receiving channel and/or on a surface of each fitting extending from the main body.

In one form the main body of the anchor means associated with an output port of the housing may comprise a substantially rectangular block or prism approximately 39mm wide, 15mm long and 8mm high and may include a first plurality, say 12, of passages extending in its longitudinal direction and adapted to respectively receive up to 12 cables each approximately 3mm in diameter. The main body may inblude a further plurality, say 14, of passages adapted to receive up to 14 fibres housed in tubes approximately 0.9mm in diameter. Alternatively, the or each passage may be formed at least partly within a respective fitting extending from the main body. Strain relieving formations as described herein may be provided in each cable/fibre receiving passage and/or on a surface of each fitting extending from the main body.

The main body of input/output anchor means may comprise alternative shapes, eg. the main body may include a taper in say the longitudinal direction relative to the housing. Such an arrangement may hold the anchor means against movement relative to the housing and may obviate the need for keying projections/recesses in the anchor means/housing.

According to the present invention there is provided a fibre separator comprising a housing having input and output ports and at least one channel in said input port through which a cable may enter said housing, said cable including a plurality of optical fibres at least partly enclosed by a first protective means, said housing having at least one passage in said output port through which one or more of said plurality of optical fibres may exit said housing, at least one of the at least one channel and the at least one passage having an associated formation for retaining said first protective means and/or a second protective means, relative to said housing, said second protective means being adapted to at least partly enclose an exiting optical fibre.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings wherein:- Fig. 1A shows an output port view of a fibre separator housing made in accordance with the principles of the present invention;

Fig. IB shows a sectional view on I-I of Figure 1A; Fig. 1C shows an input port view of the housing; Fig. ID shows a perspective view of a half shell of the housing;

Fig. 2 shows a perspective view of one form of anchor block;

Fig. 3 shows a perspective view of an alternative form of anchor block;

Figs. 4A-4C show front, plan and side elevation views of another form of anchor block;

Figs. 5A-5C show front, side elevation and plan views of another form of anchor block; Figs. 6A, 6B and 6C show front, side elevation and perspective views of another form of anchor block;

Figs. 7A, 7B, 7C and 7D show alternative plan views of anchor blocks; and

Figs. 8A and 8B show cross-sectional views of anchor block exhibiting alternative forms of cable/fibre retaining channels/passages.

Referring to Figs. 1A to 1C of the drawings, the housing 10 of the fibre separator comprises a substantially rectangular input port 11 and output port 12. Input port 11 includes keying recesses 13 and 14 and is adapted to engage an input cable/fibre anchor block as shown in Figures 2, 3, 4A-C or 5A-5C. Output port 12 includes keying recesses 15, 16 and is adapted to receive an output cable/fibre anchor block as shown in Figures 6A-6C, for example. Input port 11.and output port 12 are joined via a main cavity 17. Main cavity 17 is substantially in the form of a trapezoidal wedge, ie. it tapers from output port 12 to input port 11 in the longitudinal direction of housing 10. Main cavity 17 also tapers marginally from input port 11 to output port 12 in the longitudinal direction perpendicular to plane P (refer Fig. ID).

Fig. ID shows a half shell 10A of housing 10 formed by splitting housing 10 along longitudinally bisecting plane P. The complete housing 10 is formed by attaching an identical half shell along plane P. The two half shells (10A and the identical halfshell) may include projecting elements 18 and corresponding recesses 19 adapted to clip or snap fit together to assemble the housing 10. In one form the complete housing may be approximately 45mm wide, 85mm long and 14mm high.

Housing 10 is assembled with respective input and output anchor blocks. The anchor blocks are selected according to the required number/size(s) of each cable/fibre receiving channels/passages. The required components may be selected and assembled in the field.

Referring to Fig. 2 there is shown an input cable anchor block 20 having a single cable receiving channel 21. Channel 21 is adapted to receive a cable approximately 8mm in diameter. Anchor block 20 includes a pair of projections 22 and 23 adapted to key into recesses 13, 14 respectively in housing 10. Anchor block 20 includes barb projections 24, 25 formed in lateral side wall 26 of channel 21. Further barb projections 27, 28 are formed in opposite side wall 29 of channel 21. Barb projections 24, 25, 27 and 28 will be described in greater detail with reference to Figure 6C.

Fig. 3 shows an alternative form of input cable anchor block 30 having a pair of cable receiving channels 31 and 32. Anchor block 30 includes substantially semi-circular keying projections 33, 34 adapted to key into recesses 13, 14 respectively in housing 10. Cable receiving channels 31 and 32 each includes two pairs of barb projections of which projections 35-38 in channel 31 are representative.

Figs. 4A-4C show a still further form of input cable anchor block 40 having four cable receiving channels

41-44. Anchor block 40 includes a pair of keying projections 45, 46 adapted to key into recesses 13, 14 in housing 10. Each cable receiving channel 41 to 44 includes two pairs of barb projections (not shown) similar to those described with reference to Figs. 2 and 3.

Figs. 5A-5C shows a still further form of input cable anchor block 50 having four cable receiving channels 51-54. Anchor block 50 includes keying projections

55A/55B, 56A/56B adapted to key into recesses 13, 14 in housing 10. Channels 51-54 are partly formed in respective annular fittings 57-60 which project from the main body of anchor block 50. In the embodiment shown in Figs. 5A-5C channels 51-54 are also partly formed in the main body of anchor block 50. Alternatively the main body of anchor block 50 may be substantially hollow. Each annular fitting 57-60 includes respective barb projections

61-64 formed around its outer circumference. Each barb projection may be similar in cross section to those described with reference to Figs. 2 and 3 but is adapted to engage an internal rather than an external surface of a protective casing, sheath, tube or the like of a cable.

To ensure positive retention of the protective casing, sheath or tube the outside diameter of barb projections

61-64 should be greater than the internal diameter of the associated casing, sheath or tube.

With reference to Figs. 6A-6C there is shown an output cable/fibre anchor block 65 having a first plurality of cable receiving passages 66 to 77 and a second plurality of fibre receiving passages 78 to 91 inclusive. Passages 66 to 77 are adapted to receive respective cables each approximately 3mm in diameter and passages 63 to 76 are adapted to receive respective fibres each approximately 0.9mm in diameter. Anchor block 65 includes projections 92, 93 adapted to key into recesses

15, 16 in housing 10. Each cable receiving passage 66 to

77 includes one or two pairs of barb projections eg. 94,

95 and 96, 97. An enlarged view of barb projection 94 is shown in an inset. Projection 94 comprises a pair of projecting surfaces 94A, 94B which converge to a relatively sharp edge 94C. Surface 94A projects a distance Dl from a lateral side wall of passage 66. Dl is substantially 0.15mm in the embodiment described but may vary in other embodiments. Projecting surfaces 94A and 94B subtend an angle α. In the described embodiment α may be approximately 30° but may vary.

Each fibre receiving passage 78 to 91 includes one or two pairs of barb projections eg. 98, 99 and 100, 101. An enlarged view of barb projection 98 is shown in an inset. Projection 98 comprises a pair of projecting surfaces 98A, 98B which converge to a relatively sharp edge 98C. Surface 98A projects a distance D2 from a lateral side wall of passage 79. D2 is substantially 0.1mm in the embodiment described but may vary in other embodiments. Projecting surfaces 98A and 98B subtend an angle β. In the described embodiment β may be approximately 30^Q but may vary.

Referring to Figs. 7A-7D, there are shown alternative forms of keying projections. Fig. 7A shows substantially rectangular keying projections 102, 103 adapted to engage corresponding recesses in housing 10. Similarly Fig. 7B and 7C show triangular and trapeziodal keying projections 104, 105 and 106, 107 respectively adapted to engage complementary recesses in housing 10. In Figure 7D the side walls 108, 109 of the input/output anchor block function as a keying projection and may be adapted to key into complementary recesses in housing 10. Alternatively or additionally, the top and bottom side walls may be adapted as the keying projections.

Figs. 8A and 8B show alternative forms of cable/fibre receiving channels/passages which may be formed in the or each input/output anchor block. Fig. 8A shows a V-shaped or triangular channel/passage 110 and Figure 8B shows a substantially square section channel/passage 111. The dimensions of the channels/passages are chosen to just accommodate a fibre or cable having a diameter D. For example in Figure 8B the square channel/passage has sides substantially equal to D, the diameter of the associated fibre or cable.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention. For example, the fibre separator may be used to join or rejoin separated fibres/cables and in that case the roles described above with respect to the input/output ports and input/output anchor means may be reversed.

Claims

1. A fibre separator comprising a housing having input and output ports and at least one channel in said input port through which a cable may enter said housing, said cable including a plurality of optical fibres at least partly enclosed by a first protective means, said housing having at least one passage in said output port through which one or more of said plurality of optical fibres may exit said housing, at least one of the at least one channel and the at least one passage having an associated formation for retaining said first protective means and/or a second protective means, relative to said housing, said second protective means being adapted to at least partly enclose an exiting optical fibre.

2. A fibre separator according to Claim 1 wherein said input port includes first anchor means removably held in said housing, said at least one channel being formed at least partly in said first anchor means.

3. A fibre separator according to Claim 2 wherein said first anchor means comprises a first anchor block and said at least one channel is formed in said first anchor block.

4. A fibre separator according to Claim 3 wherein said first anchor block comprises a substantially rectangular prism and said at least one channel is formed in said prism adjacent a major surface thereof.

5. A fibre separator according to any one of the preceding claims wherein at least one said associated formation is formed on a surface of one said channel and is adapted to engage an external surface of said first protective means,

6. A fibre separator according to claim 2 wherein said first anchor means comprises a first anchor block, said first anchor block including a main body and at least one fitting extending therefrom, said at least one fitting having an external surface and an internal surface defining said at least one channel.

7. A fibre separator according to claim 6 wherein said main body comprises an rectangular prism and said at least one fitting comprises an annular projection having an outer substantially cylindrical wall defining said external surface and an inner substantially cylindrical wall defining said internal surface.

8. A fibre separator according to claim 6 or 7 wherein said associated formation is formed on said external surface and is adapted to engage an internal surface of said first protective means.

9. A fibre separator according to any one of the preceding claims wherein said output port includes second anchor means removably held in said housing, said at least one passage being formed at least partly in said second anchor means.

10. A fibre separator according to claim 9 wherein said second anchor means comprises a second anchor block and said at least one passage is formed in said second anchor block.

11. A fibre separator according to claim 10 wherein said second anchor block comprises a substantially rectangular prism and said at least one passage is formed in said prism adjacent a major surface thereof.

12. A fibre separator according to any one of the preceding claims wherein at least one said associated formation is formed on a surface of one said passage and is adapted to engage an external surface of said second protective means.

13. A fibre separator according to claim 9 wherein said second anchor means comprises a second anchor block, said second anchorr block including a main body and at least one fitting extending therefrom, said at least one fitting having an external surface and an internal surface defining said at least one passage.

14. A fibre separator according to claim 13 wherein said main body comprises an rectangular prism and said at least one fitting comprises an annular projection having an outer substantially cylindrical wall defining said external surface and an inner substantially cylindrical wall defining said internal surface.

15. A fibre separator according to claim 13 or 14 wherein said associated formation is formed on said external surface and is adapted to engage an internal surface of said second protective means.

16. A fibre separator according to any one of the preceding claims wherein the or each said associated formation comprises a barb projection.

17. A fibre separator according to any one of the preceding claims wherein said housing comprises two identical half shells.