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Title:
FITTING, IN PARTICULAR FOR A TUBE CARRYING AN OPTIC FIBRE CABLE
Document Type and Number:
WIPO Patent Application WO/2014/027259
Kind Code:
A1
Abstract:
The present invention relates to a fitting suitable for connecting to the end of at least one tube of the type carrying an optic fibre cable. The fitting comprises a fitting body defining an axial through hole through which an optic fibre cable is suitable to pass, at least one end of said body being suitable to receive inside it an end of a tube carrying said cable, the fitting body comprising a male portion and a female portion, the male portion being at least partially housed in the female portion. Said male and female portions are suitable to axially rotate in relation to one another, the male portion defining an annular seat in which an elastic sealing element is positioned suitable for surrounding a section of the optic fibre cable projecting at the tube end, The male and female portions are suitable to interact in such a way that, following the rotation of one portion in relation to another, the elastic sealing element is radially deformed inwards compressing itself around the optic fibre cable in such a way as to form a seal against the exit of fluids between the fitting body and said cable.

Inventors:
CAMOZZI GEROMINO (IT)
GNUTTI GIANLUCA (IT)
Application Number:
PCT/IB2013/055205
Publication Date:
February 20, 2014
Filing Date:
June 25, 2013
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CAMOZZI S P A SOCIETA UNIPERSONALE (IT)
International Classes:
G02B6/42; G02B6/44; H02G15/013
Foreign References:
US6069320A2000-05-30
US20120051710A12012-03-01
US6890006B22005-05-10
US5638477A1997-06-10
EP0786062A11997-07-30
Attorney, Agent or Firm:
CHIMINI, Francesco et al. (Piazza della Vittoria 11, Brescia, IT)
Download PDF:
Claims:
Claims

1. Fitting suitable for connecting to the end of at least one tube of the type carrying an optic fibre cable, the fitting comprising a fitting body defining an axial through hole through which an optic fibre cable is suitable to pass, at least one end of said body being suitable to receive within it an end of a tube carrying said cable, the fitting body comprising a male portion and a female portion, the male portion being at least partially housed in the female portion, said male and female portions being suitable to axially rotate in relation to one another, the male portion defining an annular seat in which an elastic sealing element is positioned suitable for surrounding a section of the optic fibre cable projecting from the tube end, the male and female portions being suitable to interact in such a way that, following the rotation of one portion in relation to another, the elastic sealing element is radially deformed inwards compressing itself around the optic fibre cable in such a way as to form a seal against the exit of fluids between the fitting body and sa d cable .

2. Fitting according to claim 1, wherein the male portion comprises a flexible annular tightening portion which surrounds the elastic sealing element, and wherein the female portion comprises an annular compression portion which surrounds said annular tightening portion and which, rotating in relation thereto, exerts a radial pressure on said annular tightening portion causing a radial flexion inwards.

3. Fitting according to claim 2, wherein said annular tightening portion and said annular compression portion are configured so as to jointly form a cam and counter- cam system.

4. Fitting according to the previous claim, wherein said annular tightening portion comprises a plurality of flexible teeth having an outer lateral surface with a cam profile, and wherein the annular compression portion has an inner lateral surface with a counter cam profile at each flexible tooth.

5. Fitting according to the previous claim, wherein each flexible tooth comprises a distal portion bearing the cam profile and a flexible connection portion to an intermediate portion of the male portion, the elastic sealing element being surrounded by said distal portion of the flexible teeth.

6. Fitting according to any of the previous claims, comprising anti-rotation means suitable for preventing an accidental rotation between the male portion and the female portion.

7. Fitting according to claim 4 or 5 or 6, wherein said anti-rotation means comprise a notching made on the outer lateral surface of the flexible teeth and on the inner lateral surface of the annular compression portion.

8. Fitting according to any of the previous claims, comprising fitting blocking means suitable for axially constraining the male portion to the female portion.

9. Fitting according to the previous claim, wherein said fitting blocking means comprise a radial rib made in one of the male and the female portions, and a radial groove made in the other of the male and female portions, said radial rib being suitable for snap-engaging said radial groove.

10. Fitting according to claim 8 or 9, wherein, said fitting blocking means comprise a blocking clip suitable for being inserted transversally in a respective radial seat made in the female portion so as to engage an undercut of the male portion.

11. Fitting according to any of the previous claims, wherein the male and/or female portion comprise tube blocking means suitable for hermetically retaining the end of a tube for an optic fibre cable.

12. Fitting according to the previous claim, wherein said tube blocking means are of the quick ,fit/detachment type.

13. Fitting according to the previous claim, wherein said tube blocking means comprise a nipper housed in an entrance portion of the male and/or female portion and axially translating between a rearward blocked position of the tube and a forward release position of the tube.

14. Fitting according to the previous claim, wherein said nipper comprises an annular support flange at the axial end of the male or female portion and a plurality of flexible fingers which extend axially inside said entrance portion, each finger comprising a gripping tooth suitable for clamping the outer surface of the tube and a retention tooth which engages a respective aperture made in the circumference of said entrance portion, said retention tooth having a front cam surface, suitable for interacting with the front rim of said aperture so as to cause a radial deformation of the finger outwards for the release of the tube, and a rear cam surface, suitable for interacting with the rear rim of said aperture so as to cause a radial deformation of the finger inwards for the blocking of the tube.

Description:
DESCRIPTION

"Fitting, in particular for a tube carrying an optic fibre cable"

[0001] The present invention relates to a fitting suitable for connecting to the end of at least one tube, in particular of the type carrying an optic fibre cable.

[0002] A typical optic fibre communication line comprises a bundle of optic fibres inserted in a protective sheath, in turn transported by a tube or duct, for example made of plastic. First the outer tube is installed and then the optic fibre cable is inserted in the tube. Sections of tube are connected to each other by means of fittings, for example of the type provided with a threaded collar compression mechanism.

[0003] One of the problems of installing optic fibre communication lines of this type is that of ensuring that, when the line enters a building, it does not create a channel through which gas or liquid substances may pass from the outside to the inside of the building. Such gases may be present for example in areas used for the disposal of waste ad may penetrate inside the tube carrying the optic fibre cable. For such reason, stop means of the gas or other liquid substances, in the entrance points of the line into the building must be provided for. Such stop means must form a hermetic seal between the outer tube and the fitting and between the optic fibre cable and the fitting or outer tube.

[0004] EP 0 786 062 describes a fitting for the aforementioned use, in which a sealing element, compressed following the axial drawing together of two portions of the fitting, exercises a sealing action between the optic fibre cable and the fitting.

[0005] The purpose of the present invention is to satisfy the aforementioned need to stop the gases present in the tube carrying the optic fibre cable, with a particularly reliable, safe fitting which is at the same time easy to construct and to use.

[0006] Said purpose is achieved by a fitting according to claim 1. Further characteristics and advantages of the fitting according to the invention will be made more evident from the description below of its preferred embodiments, with reference to the appended drawings, wherein :

[0007] - Figure 1 is an exploded view of the fitting according to the invention;

[0008] - figure 2 is an axial cross-section of the assembled fitting;

[0009] - figure 3 is a perspective view of the male portion of the fitting;

[0010] - figure 4 is a perspective view of the female portion of the fitting;

[0011] - figure 5 is an axial cross-section of the male portion;

[0012] - figure 6 is an axial cross-section of the fitting in use, before the tightening of the sealing element onto the optic fibre cable;

[0013] - figure 6a is a transversal axial cross-section of the fitting in the position in figure 6, in correspondence with the sealing element;

[0014] - figure 7 is a similar view to figure 6, with the sealing element compressed around the optic fibre cable;

[0015] - figure 7a is a transversal axial cross-section of the fitting in the position in figure 7, in correspondence with the sealing element;

[0016] - figure 8 is a perspective view of the fitting in an embodiment variation; and

[0017] - figure 8a is a transversal cross-section of the fitting in figure 8, in correspondence with the axial blocking means of the male and female portions.

[0018] In said drawings, reference numeral 1 globally denotes a fitting connecting to one end of at least one tube T carrying an optic fibre cable C. The fitting 1 shown in the drawings and described below is suitable for connecting two tubes T to each other, in particular the two adjacent ends are aligned. It is clear to a person skilled in the art that the teaching of the present invention may be applied to fittings suitable for connecting to the end of one tube only or to the ends of more than two tubes, for example in a Y-configuration .

[0019] In the continuation of the description, except where specified otherwise, the terms "inner" and "outer" are used in a radial sense, that is, with reference to the main axis of the fitting or to the axis of the optic fibre cable C. Furthermore, the terms "front" and "rear", "forward" and "rearward" are used in an axial or longitudinal sense , and in particular , with reference to the direction of insertion of the tubes T in the fitting.

[0020] In a general embodiment, the fitting 1 according to the invention comprises a fitting body 10 which extends mainly along a fitting axis X and which defines an axial through hole 12 through which an optic fibre cable C is suitable to pass. The fitting body 10 comprises a male portion 14 and a female portion 16, the male portion 14 being at least partially housed in the female portion 16. At least one of said male 14 or female 16 portions, for example both, as in the embodiment shown, comprise an entrance portion 18 open at the end and suitable to receive and block so as to seal tight against gases or liquids, a respective end of a tube T inside which the optic fibre cable C passes. [0021] In one embodiment, said entrance portion 18 forms, with the tube blocking means described below, an entrance hole 20 having a diameter substantially equal to the outer diameter of the tube T. Said entrance hole 20, is delimited at the front, that is on the side opposite the entrance aperture, by an annular abutment shoulder 22 for the end of the tube T.

[0022] According to one aspect of the invention, the male 14 and female 16 portions are suitable to axially rotate in relation to one another. The male portion 14 defines an annular seat 24 in which an elastic sealing element 26 is positioned suitable for surrounding a section of the optic fibre cable C projecting from the ends of the tubes T. Following the rotation of one portion of the fitting body in relation to the other, the elastic sealing element 26 is radially deformed inwards, compressing itself around the optic fibre cable C in such a way as to form a seal against the exit of gas or fluids, between the fitting body 10 and said cable C.

[0023] More specifically, the male portion 14 comprises a flexible annular tightening portion 28 which surrounds the elastic sealing element 26. The female portion 16 comprises an annular compression portion 30 which surrounds said annular tightening portion 28 and which, rotating in relation thereto, exerts a radial pressure on said annular tightening portion 28 causing a . radial flexion inwards.

[0024] In a preferred embodiment, said annular tightening portion 28 and said annular compression portion 30 are configured so as to jointly form a cam and counter-cam system.

[0025] In particular, according to one embodiment said annular tightening portion 28 comprises a plurality of flexible teeth 32, for example four teeth 32 circumferentially equidistant from each other, having a longitudinal extension, that is to say extending parallel to the axis of the fitting X. Each flexible tooth 32 has an outer lateral surface 34 with a cam profile. For example, said cam profile is realised with an outer lateral surface 34 arched but not parallel to the inner lateral surface, so that the radial thickness of each flexible tooth 32 increases progressively from one end of the tooth to the other. In addition, one end of the tooth 32, for example the thinner end, has a radial projection 36 which extends outwards.

[0026] The annular compression portion 30 has an inner lateral surface with a counter cam profile at each flexible tooth 32. For example, said lateral inner surface has, at each flexible tooth 32, an arched surface 40 complementary to the outer lateral surface 34 of the flexible teeth. Adjacent arched surfaces 40 of the annular compression portion 30 are separated from each other by a substantially radial annular abutment shoulder 42, against which the radial projection 36 is suitable to abut. This radial projection 36 delimits the reciprocal rotation of the two portions of the fitting body during the release step of the elastic sealing element 26. In addition, said radial projection 36 performs the further important function of helping to increase and better distribute the flattening force of the respective flexible tooth on the sealing element 26 during the radial deformation of the flexible teeth 32. In fact, when the male portion 14 rotates in relation to the female portion 16, such radial projection 36 remains in

r

contact with the arched surface 40, preventing the thinner end portion of the respective flexible tooth 32, not being engaged by said arched surface 40, from contributing to exercising pressure on the sealing element 26.

[0027] Consequently, starting from an initial inactive configuration, in which the limit stop radial projections 26 rest against the respective abutment shoulders 42, and the flexible teeth 32 are not radially deformed, an annular rotation of the male portion 14 in relation to the female portion 16 causes the sliding of the arched surfaces 40 of the annular compression portion 30 on the outer lateral surfaces 34 of the flexible teeth 3. During such rotation, the thicker zones of the compression portion 30 and of the flexible teeth 32 come to overlap causing the flexion of the teeth 32 inwards and the consequent radial compression of the elastic sealing element 26 on the outer surface of the optic fibre cable C

[0028]

[0029] In a preferred embodiment, each flexible tooth 32 comprises a distal portion 32' bearing the cam profile 34 and a flexible portion 32" connecting to an intermediate portion 44 of the male portion 14. In other words, the flexible teeth 32 are made at the front end of the male portion 14. The elastic sealing element 26 being surrounded by said distal portion 32' of the flexible teeth 32. The flexible portion 32", preferably of constant thickness and thinner than the distal portion 32 ' , is suitable for flexing radially inwards and is that which permits the radial deformation of the flexible teeth 32, as may be seen in particular in figure 7.

[0030] Preferably, the elastic sealing element 26 is a cylindrical shape with a through hole 26'. Preferably, in addition, the height of said elastic sealing element 26 is substantially equal to the axial extension of the distal portion 32' of the flexible teeth 32. Preferably, in addition, in the inactive configuration, that is to say not compressed, the outer diameter of the elastic sealing element 26 is substantially equal to the diameter of the circumference defined by the inner surface of the flexible teeth 32.

[0031] In a preferred embodiment, the fitting 1 is provided with anti-rotation means suitable for preventing an accidental rotation between the male portion 14 and the female portion 16. For example, said anti-rotation means comprise a notching 34', 40' made respectively on the outer lateral surface 34 of the flexible teeth 32 and on the inner lateral surface 40 of the annular compression portion 30. Such notchings 34', 40', meshing with each other, permit an annular "stepped" rotation of the male portion 14 in relation to the female portion 16, both in the compression step of the elastic sealing element 26 and in the release step of said elastic element. Advantageously, the teeth of the notchings 34', 40' have an angulation such as to prevent, once the male portion has rotated in relation to the female portion with consequent flattening of the sealing element, its natural return to the initial position.

[0032] In an embodiment shown in figure 8, the fitting has, alternatively or in conjunction with said notchings 34', 40', further limit stop means which limit the rotation of the male portion in relation to the female portion, advantageously made integrally on the two portions. For example, the male portion bears a limit stop eyelet 70 in which a limit stop tooth 72 made on the female portion 16, engages.

[0033] In addition, in a preferred embodiment, the fitting 1 is provided with fitting blocking means suitable for axially constraining the male portion 14 to the female portion 16. In one embodiment, said fitting blocking means comprise a radial rib 50 made in one of the male or female portions, and a radial groove 52 made in the other of the male or female portions. Preferably, said radial rib 50 is suitable for snap-engaging said radial groove 52. For example, the radial rib 50 is made in the intermediate portion 44 of the male portion 14.

[0034] For the axial blocking of the two male and female portions, in an embodiment variant shown in figures 8, 8a, the fitting has further fitting blocking means alternatively or in combination with the radial rib 50 and the radial groove 52. For example, said fitting blocking means comprise a blocking clip 74 suitable for being inserted transversally in a respective radial seat 76 made in the female portion 16 so as to engage, as well as said seat 76, an undercut 78 of the male portion 14, for example made in the intermediate portion 44. The axial movement of the male portion 14 thus proves prevented by such blocking clip 74.

[0035] In a preferred embodiment, the male portion 14 is at least partially housed in a hollow cylindrical portion 54 of the female portion 16. Said hollow cylindrical portion 54 has an end wall 56 which, on the side facing towards the entrance portion 18 forms the radial abutment shoulder 22 for the support of the tube T and, on the side facing the male portion 14, forms a support plane for the distal portion 32' of the flexible teeth 32 and for the elastic sealing element 26. The side wall of said hollow cylindrical portion 54, and in particular a rear part thereof which extends from the end wall 56 and surrounds the distal portion 32' of the flexible teeth 32 forms the compression portion 30. The intermediate portion 44 of the male portion 14 comprises an axial projection 401 which forms the radial support shoulder 22 of the tube T and which is housed inside the hollow cylindrical portion 54, a front radial portion 402, also housed inside the hollow cylindrical portion 54 and bearing the radial rib 50, and a rear radial portion 403, which abuts with the front rim of the hollow cylindrical portion 54 and having for example an outer diameter substantially equal to that of said hollow portion 54. Advantageously, when the elastic sealing element 26 is inserted in the hollow cylindrical portion 54, resting against the end wall 56, the axial projection 401 of the intermediate portion 44 abuts with said elastic sealing element 26. The latter, therefore, constrained between the end wall 56 and the axial projection 401, is prevented from moving axially.

[0036] Returning now to the entrance portions 18, these are fitted with tube blocking means suitable for hermetically retaining the end of the tube T. In one advantageous embodiment, said tube blocking means are of the quick fit/detachment type. According to one embodiment, each entrance portion 18 : has a rear portion 181 having a greater diameter than that of the tube T, distanced in relation to the abutment shoulder 22 of said tube T. Said rear portion 181 has a plurality of apertures 182 circumferentially equidistant to each other. Inside said rear portion 181 a tube sealing gasket 183, such as an o- ring, and a washer 184 are placed. In addition, a nipper 185 is positioned in the open end portion of said rear portion 181. The nipper 185 has an annular flange 186 against which the axial end surface of the entrance portion 18 abuts. Said annular flange 186 has an axial aperture 187 having a diameter substantially equal to that of the tube T. Ά plurality of flexible fingers 188 extend axially from said annular flange 186 into the entrance portion 18. The nipper 185 is retained inside the entrance portion 18 by means of retention teeth 190, each one extending radially outwards and preferably made in one piece with, the flexible fingers 188. Each retention tooth 190 engages a respective aperture 182 of the rear portion 181. In particular, each retention tooth 190 has a front cam surface 191, suitable for interacting with the front rim 182' of said aperture 182 so as to cause a radial deformation of the flexible finger 188 outwards for the release of the tube, when the nipper 185 is pushed into the forward position in the entrance portion 18, and a rear cam surface 192, suitable for interacting with the rear rim 182" of said aperture 182 so as to cause a radial deformation of the flexible finger 188 inwards for the blocking of the tube T, when the nipper is made to reverse. From each flexible finger 188 a gripping tooth 194 extends radially suitable for clamping the outer surface of the tube T to keep it inside the entrance portion 18.

[0037] In use, the fitting 1 is assembled by inserting the elastic sealing element 26 between the flexible teeth 32 of the male portion 14. The male portion 14 is then axially inserted in the female portion 16. To connect a tube T to the entrance portion 18 of the fitting 1, the end of the tube T is pushed into the axial aperture 187 of the annular flange 186 and inside the entrance hole 20, until it abuts with the abutment shoulder 22. While it penetrates the entrance portion 18, the end of the tube T places the flexible fingers 188 in tension so that the respective gripping teeth 194 exercise a clamping action on the outer surface of the tube T. In addition, when the tube T has abutted with the abutment shoulder 22, its outer surface forms a sealed contact with the gasket 183.

[0038]

[0039] At this point it is possible to make the optic fibre cable C pass through the fitting 1. Lastly, the male element 14 is rotated in relation to the female element 16, so as to cause ' the radial deformation inwards of the flexible teeth 32 and thus the compression of the flexible sealing element- 26 around the optic fibre cable C.

[0040] Consequently, the flexible sealing element 26, when compressed around the optic fibre cable C, prevents any gases or liquids present inside the tube T from propagating inside another tube connected to the fitting or into an external environment downstream of the fitting. In addition, the sealing gasket 183 prevents the passage of gases or liquids from a tube T to outside the fitting .

[0041] It is to be noted that if an attempt is made to extract the tube T from the entrance portion 18 a rearward movement of the nipper 185 is caused and thus the interaction of the rear cam surface 192 with the rear rim 182" of the apertures 182. Such interaction causes a radial compression inwards of the flexible fingers 188 and thus an increase in the clamping force of the gripping teeth 194 on the outer surface of the tube T. The latter cannot therefore be extracted from the entrance portion 18. To be able to extract the tube T, it is instead necessary to push the clamp 185 into the forward position, with the annular flange 186 abutting with the open end of the entrance portion 18, causing the interaction between the front cam surface 191 of the retention teeth 190 and the front rim 182' of the apertures 182. Such interaction causes the radial widening of the flexible fingers 188 and thus the disengagement of the gripping teeth 194 from the outer surface of the tube T, which may thus be extracted. To remove the optic fibre cable C, it is sufficient to rotate the male portion 14 and female portion 16 in relation to one another in the direction opposite to that of the rotation performed during the blocking step. The flexible teeth 32 return elastically into an inactive position (Figure 7) permitting the return of the elastic sealing element 26 to its rest position, with its inner lateral surface distanced from the optic fibre cable C, or in any case, not in compression on the latter.