Connection box and method for connecting optical cables

It is disclosed a connection box for housing a connection between a distribution cable and a drop cable of an optical access network. The connection box comprises an outer casing and a detachable connection plate, which may be completely housed therein. The outer casing comprises a fixing member for fixing the distribution cable. The connection plate comprises a first surface with a fixing member for fixing an end of the drop cable and a second, opposite surface with a connector holder for holding the optical connector between a distribution fiber extracted from the distribution cable and a drop fiber extracted from the drop cable. The perimeter edge of the connection plate exhibits an indentation forming a fiber passage allowing the drop fiber passing from the first surface to the second surface of the connection plate. It is also disclosed a method for connecting two optical cables using such connection box.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage of International Application No. PCT/IT2017/000262, filed on Nov. 23, 2017, which application is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to the field of optical access networks. In particular, the present invention relates to a connection box for connecting optical cables.

BACKGROUND

An FTTH (Fiber To The Home) network is an optical access network providing a number of end users with communication services, e.g. with services requiring data transmission at a rate of some hundreds of Mbit/s or more.

Typically, an FTTH network comprises a distribution cabinet cooperating with a transport network and a number of optical cables (namely, cables comprising optical fibers) which connect the distribution cabinet with termination boxes arranged at the various user's premises. In particular, an optical cable comprising multiple optical fibers typically exits the distribution cabinet and runs through an area (e.g. a residential area) where the houses of different end users are placed. Such optical cable will be termed herein after “distribution cable” and the optical fibers comprised therein will be termed “distribution fibers.”

The distribution cable may be either laid down in underground ducts running besides the houses or, alternatively, it may be horizontally fixed to the houses' façades. In the latter case, the deployment of the FTTH network requires using cables and other components which exhibit high resistance to stresses typical of outdoor environments and which are effectively sealed against seepage and dust infiltrations.

In order to connect the termination box of an end user to the distribution cable, an optical cable called “drop cable” is typically used. The drop cable may comprise one or more optical fibers (up to 4, typically), which are termed herein after “drop fibers”.

For connecting the drop cable of an end user to the distribution cable, a first window is typically cut in the external sheath of the distribution cable at a first mid-span position thereof and then one or more distribution fibers (depending on the number of drop fibers of the drop cable) are cut through this first window. Then, a second window (also termed “tapping window”) is cut in the external sheath of the distribution cable at a second mid-span position thereof, intermediate between the distribution cable end connected to the distribution cabinet and the first window, possibly on the façade of the house where the end user resides. The cut distribution fiber(s) is then drawn through the tapping window and connected (e.g. by means of mechanical splice(s) or fusion splice(s)) to the drop fiber(s).

Both the first window and the tapping window cut in the external sheath of the distribution cable are typically protected against seepage and dust infiltration by suitable boxes fixed to the distribution cable. The box protecting the tapping window also typically has the function of housing the optical connector(s) (mechanical splice(s) or fusion splice(s)) between distribution fiber(s) and drop fiber(s) and any extra-length of the fibers, and is therefore termed herein after also “connection box”.

EP 2 108 987 describes an optical box for housing the connection between one or more optical fibers extracted from a distribution cable and one or more optical fibers extracted from a subscriber cable. The box comprises a first part having a rectangular base, two opposite sidewalls and means for being fastened to the distribution cable (e.g. clamp collars or adhesive strips). A second part of the box comprises two rectangular cassettes reciprocally hinged, the first cassette having an opening for the passage of fibers and the second cassette having splices or connectors. In order to make the connection, a fiber is extracted from the distribution cable through a tapping window cut in the cable sheath, and then the distribution cable is fixed to the first part of the box. Also the subscriber cable may be fixed to the first part of the box. The fiber from the distribution cable and the fiber from the subscriber cable are passed through the opening in the first cassette of the second part of the box. Then, the fibers are connected (e.g. spliced) and then the operator fastens the second part of the box to the first part. The fibers are then coiled and arranged in the first cassette of the second part of the box. The second part of the box is finally closed.

SUMMARY

In one embodiment, a connection box comprises an outer casing comprising a first fixing member configured to fix a first optical cable to the outer casing at a mid-span position and a connection plate detachable from the outer casing and configured to be completely housed within the outer casing. The connection plate comprises a first surface comprising a second fixing member configured to fix an end of a second optical cable to the connection plate, and a second surface opposite to the first surface. The second surface comprises a connector holder configured to hold an optical connector between a first optical fiber extracted from the first optical cable at the mid-span position and a second optical fiber extracted from the end of the second optical cable. The connection plate further comprises a perimeter edge exhibiting an indentation which forms a fiber passage configured to allow passage of the second optical fiber from the first surface to the second surface of the connection plate. The connection box is configured to house a connection between the first optical cable and the second optical cable at the mid-span position of the first optical cable.

In an embodiment, a method for connecting a first optical cable and a second optical cable at a mid-span position of the first optical cable includes extracting a first optical fiber from the first optical cable at the mid-span position and fixing the first optical cable to an outer casing of a connection box at the mid-span position. The method further includes fixing an end of the second optical cable to a first surface of a connection plate of the connection box, the connection plate being detached from the outer casing. The method further includes making a second optical fiber extracted from the end of the second optical cable pass from the first surface of the connection plate to a second, opposite surface of the connection plate through a fiber passage formed by an indentation of a perimeter edge of the connection plate and completely housing the connection plate in the outer casing of the connection box. The method further includes connecting the first optical fiber extracted from the first optical cable to the second optical fiber extracted from the end of the second optical cable with an optical connector and arranging the optical connector on the second surface of the connection plate.

In an embodiment, an assembly includes a first optical cable, a second optical cable, and a connection box housing a connection between the first optical cable and the second optical cable at a mid-span position of the first optical cable. The connection box comprises an outer casing comprising a first fixing member configured to fix the first optical cable to the outer casing at the mid-span position; and a connection plate detachable from the outer casing and configured to be completely housed within the outer casing. The connection plate comprises a first surface comprising a second fixing member configured to fix an end of the second optical cable to the connection plate, a second surface opposite to the first surface and comprising a connector holder configured to hold an optical connector between a first optical fiber extracted from the first optical cable at the mid-span position and a second optical fiber extracted from the end of the second optical cable, and a perimeter edge exhibiting an indentation which forms a fiber passage configured to allow passage of the second optical fiber from the first surface to the second surface of the connection plate.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The Applicant has noticed that the optical box of EP 2 108 987 exhibits some drawbacks.

In particular, the operation of connecting the distribution cable and the subscriber cable using this optical box is quite inconvenient for the operator.

The step of making the distribution fiber and subscriber fiber pass through the opening of the second cassette indeed requires a certain manual skill, which less experienced operators typically do not have. Also the step of arranging the extra-length of subscriber fiber and distribution fiber in the second cassette may be difficult and expose the fibers to the risk of being pierced or excessively bent or pressed.

The optical box of EP 2 108 987 is moreover not particularly suitable for being effectively sealed against seepage and dust infiltrations, as required e.g. for façade installation. Such an operation would indeed require providing the box with some additional sealing components, which would disadvantageously increase the complexity and cost of the box. This is particularly undesired if the box is intended for a single end user, who shall bear the entire cost of the box.

In view of the above, the Applicant has tackled the problem of providing a connection box for an optical access network and a method for connecting optical cables of an optical access network which overcome at least one of the aforesaid problems.

In particular, the Applicant has tackled the problem of providing a connection box for housing the connection between two optical cables—in particular, but not exclusively, a distribution cable and a drop cable of an optical access network—which is suitable for façade installation, has a reduced cost and makes the operation of connecting the two optical cables particularly operator-friendly.

The Applicant has also tackled the problem of providing a method for connecting two optical cables—in particular, but not exclusively, a distribution cable and a drop cable of an optical access network—which is particularly operator-friendly.

According to embodiments of the present invention, the above problems are solved by a connection box for housing a connection between a first optical cable (in particular, but not exclusively, the distribution cable of an optical access network) and a second optical cable (in particular, a drop cable of an optical access network) at a mid-span position of the distribution cable, comprising an outer casing and a connection plate detachable from the outer casing and configured to be completely housed therein. The outer casing comprises a first fixing member for fixing the distribution cable to the outer casing at its mid-span position. The connection plate comprises (i) a first surface comprising a second fixing member for fixing an end of the drop cable to the connection plate, (ii) a second surface opposite to the first surface and comprising a connector holder for holding an optical connector between a distribution fiber extracted from the distribution cable at the mid-span position and a drop fiber extracted from the drop cable end and (ii) a perimeter edge exhibiting an indentation which forms a fiber passage allowing passage of the drop fiber from the first surface to the second surface of the connection plate.

In order to connect the distribution cable to the drop cable using such connection box, according to embodiments of the present invention a distribution fiber is firstly extracted from the distribution cable at a mid-span position thereof, and the distribution cable is fixed to the outer casing of the connection box with the connection plate detached therefrom; then, an end of the drop cable is fixed to the first surface of the connection plate. The operator then makes the drop fiber pass from the first surface to the second surface of the connection plate through the fiber passage formed by the indentation of the connection plate perimeter edge, and the connection plate is then housed within the outer casing of the connection box. The operator then connects the distribution fiber with the drop fiber by means of an optical connector. The optical connector is finally arranged in the connection holder provided on the second surface of the connection plate.

The connection box of the invention is suitable for façade installations and, at the same time, has a particularly reduced cost.

In the connection box of the invention, indeed, the components needed to hold the optical connector between drop and distribution fibers (as well as those to guide the drop fiber from the point where it exits the drop cable to the point where the optical connector is held and those for arranging the extra-length of distribution fiber and drop fiber) are provided on the connection plate. The outer casing does not comprise any retaining component, except the fixing member for fixing the distribution cable. Hence, the outer casing may have a particularly simple structure with smooth surfaces (no tabs, protrusions, etc.).

On one hand, this implies that the outer casing can be manufactured (e.g. by plastic molding) at a very reduced cost. Moreover, the connection box may be provided to the operator with the connection plate detached from the outer casing, hence substantially with no assembly cost. The overall cost of the connection box is therefore particularly reduced, which is particularly advantageous, since the connection box is intended for a single end user who entirely bears its cost.

On the other hand, the absence of tabs, protrusions etc. from the outer casing surfaces implies the absence of corresponding holes or apertures which would be inevitably formed during the manufacturing by molding. The absence of any hole or aperture on the surfaces of the outer casing, in combination with the fact that the connection plate in use is completely housed within it, advantageously provides a box which may be easily hermetically sealed against seepage and dust infiltration, and which is therefore suitable for façade installation. If the outer casing comprises a base and cover, a sealing degree equal to IP-44 (International Protection) may be reached by coupling the base to the cover in a hermetic way, with no need to provide any additional sealing component.

Besides, the operation of connecting the drop cable to the distribution cable using this connection box is particularly operator-friendly, so that it may be carried out even by less experienced operators with a minimum risk of damaging the fibers.

In order to bring the drop fiber from the point where it exits the drop cable to the point where the optical connector shall be held, indeed, the operator only has to make the drop fiber pass from the first surface to the second surface of the connection plate through the fiber passage formed by the indentation in the perimeter edge of the connection plate. This is much easier than making the drop fiber pass through perimetrically closed apertures or slits.

As to the distribution fiber, the fiber passage formed by the indentation in the perimeter edge of the connection plate allows to easily pass also this fiber from the distribution cable directly above the second surface of the connection plate, where the connection holder is provided. This operation may be easily done after the connection plate has been already fitted into the outer casing, with no need to make the distribution fiber pass through any perimetrically closed apertures or slits.

According to a first aspect, the present invention provides a connection box for housing a connection between a first optical cable and a second optical cable at a mid-span position of the first optical cable, the connection box comprising: an outer casing comprising a first fixing member configured to fix the first optical cable to the outer casing at the mid-span position; a connection plate detachable from the outer casing and configured to be completely housed within the outer casing, the connection plate comprising: a first surface comprising a second fixing member configured to fix an end of the second optical cable to the connection plate; a second surface opposite to the first surface and comprising a connector holder configured to hold an optical connector between a first optical fiber extracted from the first optical cable at the mid-span position and a second optical fiber extracted from the end of the second optical cable; and a perimeter edge exhibiting an indentation which forms a fiber passage configured to allow passage of the second optical fiber from the first surface to the second surface of the connection plate.

Preferably, the outer casing comprises a base and a cover.

Preferably, the connection plate is configured to be completely housed within the base of the outer casing with the first surface facing the base.

Optionally, the first surface of the connection plate comprises at least one first attaching member configured to attach the connection plate to the outer casing, and the base of the outer casing comprises at least one second attaching member configured to engage with the at least one first attaching member.

According to an advantageous variant, the at least one first attaching member comprises at least one pillar, while the at least one second attaching member comprises at least one hollow cylinder configured to receive the at least one pillar.

Alternatively, the cover is configured to block the connection plate in the base, when the cover is closed onto the base.

Preferably, the first surface of the connection plate comprises two second fixing members configured to fix the end of the second optical cable to the connection plate, the two second fixing members being arranged at two consecutive corners of the connection plate.

Preferably, the first surface of the connection plate comprises at least one guiding wall configured to define two alternative fiber paths running over the first surface, from the second fixing member configure to fix the end of the second optical cable to the connection plate, to the fiber passage formed by the indentation in the perimeter edge of the connection plate.

Preferably, the two alternative paths are configured to guide the second optical fiber so that it reaches the fiber passage from anyone of two opposite directions.

Preferably, the second surface of the connection plate comprises a peripheral area for receiving an extra-length of the first optical fiber and the second optical fiber.

Preferably, the connector holder is arranged in an elevated position above a portion of the peripheral area for receiving the extra-length of the first optical fiber and the second optical fiber.

According to advantageous variants, the outer casing comprises at least one third fixing member configured to fix the second optical cable to the outer casing, when the connection plate with the second optical cable fixed thereto is completely housed within the outer casing.

Preferably, the outer casing is configured to be sealed against seepage and dust infiltration, when in use.

According to a second aspect, the present invention provides a second optical cable and a connection box housing a connection between the first optical cable and the second optical cable at a mid-span position of the first optical cable, wherein the connection box is as set forth above.

According to a third aspect, the present invention provides a method for connecting a first optical cable and a second optical cable at a mid-span position of the first optical cable, the method comprising: a) extracting a first optical fiber from the first optical cable at the mid-span position and fixing the first optical cable to an outer casing of a connection box at the mid-span position; b) fixing an end of the second optical cable to a first surface of a connection plate detached from the outer casing; c) making a second optical fiber extracted from the end of the second optical cable pass from the first surface of the connection plate to a second, opposite surface of the connection plate through a fiber passage formed by an indentation of a perimeter edge of the connection plate and completely housing the connection plate in the outer casing of the connection box; and d) connecting the first optical fiber extracted from the first optical cable to the second optical fiber extracted from the end of the second optical cable by means of an optical connector (8) and arranging the optical connector (8) on the second surface (5b) of the connection plate.

Preferably, step a) comprises fixing the first optical cable to a base of the outer casing.

Preferably, step c) comprises arranging the second optical fiber in anyone of two alternative fiber paths running over the first surface of the connection plate, from the point where the end of the second optical cable is fixed to the connection plate, to the fiber passage formed by the indentation in the perimeter edge of the connection plate.

Preferably, step c) comprises arranging the connection plate with the first surface facing a base of the outer casing.

Preferably, step c) comprises arranging the connection plate with the fiber passage formed by the indentation of the perimeter edge of the connection plate positioned above a tapping window of the first optical cable, though which the first optical fiber is extracted from the first optical cable.

Preferably, step c) comprises bringing the first optical fiber on the second surface of the connection plate housed within the outer casing directly from the tapping window of the first optical cable, through the fiber passage formed by the indentation of the perimeter edge of the connection plate.

Preferably, step d) also comprises arranging an extra-length of the first optical fiber and second optical fiber on the second surface of the connection plate.

Preferably, the method also comprises sealing the connection box against seepage and dust infiltration.

As mentioned above, the connection box according to embodiments of the present invention comprises an outer casing and a connection plate detachable from the outer casing.

The outer casing1according to an embodiment of the present invention is shown inFIGS. 1aand1b.

The outer casing1comprises a base2and a cover3. The base2preferably has a substantially rectangular flat bottom21and four sidewalls, including two short sidewalls22aand two long sidewalls22b.

Each short sidewall22aexhibits a U-shaped recess23configured to allow passage of an optical cable, in particular a distribution cable of an optical access network. At least one of the short sidewalls22a(preferably both the sidewalls22a, as shown in the drawings) also exhibits a further U-shaped recess24configured to allow passage of an optical cable, in particular a drop cable of an optical access network.

The base2is also provided with at least one fixing element23aconfigured to fix the optical cable entering and exiting the base2through the recesses23(namely, the distribution cable) to the outer casing1. In the embodiment shown in the drawings, such fixing element comprise—for each recess23—a respective tab protruding23atowards the exterior of the base2in proximity of the recess23.

The base2is also optionally provided with at least one fixing element24aconfigured to fix the optical cable entering the base2through one of the recesses24(namely, the drop cable) to the outer casing1. In the embodiment shown in the drawings, such means comprise—for each recess24—a tab24aprotruding towards the exterior of the base2in proximity of the recess24.

The base2of the outer casing1preferably comprises inner walls25a,25bdefining—together with the sidewalls22a,22b—a perimeter trench26suitable for being filled with a sealing material (not shown in the drawings), for the purpose of efficiently sealing the outer casing1against seepage and dust infiltration. The sealing material may be e.g. a gel by which the trench26is filled upon manufacturing of the outer casing1, or a preformed sealing member (e.g. a preformed rubber member) conformed to fit in the trench26. Alternatively, gaskets and/or grommets may be provided for appropriate sealing. The short inner sidewalls25apreferably comprise U-shaped recesses aligned with the recesses23and24, to allow passage of the distribution cable and drop cable.

The base2of the outer casing1optionally comprises at least one attaching member27configured to attach the connection plate to the base2. Such at least one attaching member27preferably comprise at least one hollow cylinder27configured to receive at least one corresponding pillar provided on the connection plate, as it will be described in detail herein after. In the embodiment shown in the drawings, the base2comprises two hollow cylinders27protruding from the bottom21of the base2. The hollow cylinders27are arranged parallel to the long sidewalls22bof the base2, preferably substantially aligned with the recesses24allowing the passage of the drop cable.

The cover3preferably has a ceiling31and four sidewalls, including two short sidewalls32aand two long sidewalls32b.

Each short sidewall32aexhibits a U-shaped recess33configured to match with the recess23in the corresponding sidewall22aof the base2, so as to allow passage of the distribution cable. At least one of the short sidewalls32a(preferably both the sidewalls32a, as shown in the drawings) also exhibits a further U-shaped recess34configured to match with the recess24in the corresponding sidewall22aof the base2, so as to allow passage of the drop cable.

The U-shaped recesses33and34on each short sidewall32aof the cover3are preferably protected by a protection winglet35protruding from the sidewall32atoward the exterior of the cover3.

The cover3of the outer casing1preferably comprises inner walls35a,35bdefining—together with the sidewalls32a,32b—a perimeter trench36filled with a sealing material (e.g. a gel or a rubber, not shown in the drawing) and suitable for matching with the trench26in the base2, so as to form a sealing chamber efficiently sealing the outer casing1against seepage and dust infiltration. The short inner sidewalls35apreferably comprise U-shaped recesses aligned with the recesses33and34, to allow passage of the distribution cable and drop cable.

A central portion31′ of the bottom31of the cover3, which is enclosed by the inner walls35a,35b, is preferably lifted relative to the outer portion of the bottom31, so that the central chamber of the outer casing1—which is defined by the inner walls25a,25bof the base2and the inner walls35a,35bof the cover3—has a thickness higher than the surrounding sealing chamber.

The cover3is optionally hinged to the base2, e.g. by means of a life hinge4. Alternatively, the cover3may be detachable from the base2.

The base2preferably comprise first securing members28and the cover3preferably comprises corresponding second securing members38configured to cooperate with the first securing members to secure the cover3on the base2, so as to close the outer casing1.

The outer casing1has a width (namely, a size along the short sidewalls22a) preferably comprised between 50 mm and 60 mm, more preferably between 55 mm and 58 mm. Further, the outer casing1has a length (namely, a size along the long sidewalls22b) preferably comprised between 140 mm and 160 mm, more preferably between 150 mm and 155 mm. Further, the outer casing1has a thickness comprised between 20 mm and 25 mm, more preferably between 22 mm and 25 mm.

As shown inFIGS. 2a, 2bthe connection plate5of the connection box is a flat plate having a substantially rectangular shape with rounded corners, and having two opposite surfaces5a(also termed herein after “first surface” and shown inFIG. 2a) and5b(also termed herein after “second surface” and shown inFIG. 2b).

The connection plate5is configured so that it may be completely housed within the outer casing1—in particular, within the central chamber defined by the inner walls25a,25bof the base2and the inner walls35a,35bof the cover3—when the outer casing1is closed, namely when the cover3is secured to the base2. The connection plate5accordingly has width and length lower than the width and length of the base2. In particular, the connection plate5preferably has width and length lower than the lengths of the inner walls25a,25bof the base2.

The first surface5aof the connection plate5preferably comprises at least one fixing member51configured to fix an end of an optical cable, in particular a drop cable of an optical access network, to the connection plate5. According to the embodiment shown inFIGS. 2aand 2b, such fixing member51comprises a pair of protrusions51configured to receive optical cables (in particular, drop cables) of different diameters. The protrusions51are preferably arranged at a rounded corner of the connection plate5. More preferably, as shown inFIG. 2a, the first surface5aof the connection plate5comprises two couples of protrusions51, which are preferably arranged at the two rounded corners adjacent to a same long side of the connection plate5.

On the first surface5aof the connection plate5, preferably, two curved guiding walls52are provided. The curved guiding walls52are preferably arranged so as to define two curved fiber paths on the first surface5aof the connection plate5. Preferably, a number of retaining tabs53radially protrude from the upper edge of the curved guiding walls52towards the perimeter of the connection plate5.

Preferably, on the first surface5a, a couple of directing walls54arranged in the shape of “V” is interposed between each couple of protrusions51and each curved guiding wall52.

Preferably, the connection plate5comprises on the first surface5aat least one attaching member55configured to cooperate with the at least one attaching member27provided on the base2of the outer casing1, to attach the connection plate5to the outer casing1.

Such at least one attaching member55preferably comprises at least one pillar configured to be fitted in the at least one hollow cylinder27of the base2. In the embodiment shown in the drawings, two pillars55are provided on the first surface5aof the connection plate5. The pillars55have a hexagonal cross section configured so that the vertexes of the hexagon interfere with the central holes of the hollow cylinders27, when the pillars55are fitted therein. The pillars55are preferably arranged along the long side of the connection plate5which is adjacent to the rounded corners where the couples of protrusions51are arranged.

The attaching members27and55are optional. According to embodiments not shown in the drawings, the cover3may be configured to block the connection plate5in the base2when it is closed onto the base2.

The connection plate5preferably comprises a perimeter wall56projecting from the perimeter edge of the connection plate5and surrounding the second surface5bof the connection plate5.

The perimeter edge of the connection plate5preferably exhibits an indentation5cthat, as it will be described in detail herein after, forms a fiber passage allowing the drop fiber to pass from the first surface5ato the second surface5bof the connection plate5. The indentation5cis preferably provided at a median position along a long side of the connection plate5, preferably the long side opposite to that adjacent to the rounded corners where the couples of protrusions51are arranged on the first surface5a.

On the second surface5bof the connection plate5, preferably, two curved inner walls57are preferably provided which, together with the perimeter wall56, define on the second surface5bof the connection plate5aperipheral area suitable for arranging an extra-length of the distribution fiber and drop fiber, as it will be described in detail herein after. Fiber retaining tabs57apreferably radially protrude from the upper edge of the outer wall56and extend towards the curved inner walls57.

The second surface5bof the connection plate5also comprises a connector holder58configured to hold an optical connector between distribution fiber and drop fiber, such as a mechanical splice or a fusion splice. The connector holder58is configured to keep the optical connector in an elevated position above the second surface5b, so that the extra-length of the distribution fiber and drop fiber may be arranged also underneath the optical connector, which accordingly acts as a fiber retaining element. This arrangement of the connector holder58advantageously allows saving space on the second surface5bof the connection plate5. The connector holder58is preferably arranged at a median position along a long side of the connection plate5, preferably along the same long side of the connection plate5which is adjacent to the rounded corners where the couples of protrusions51are arranged on the first surface5a.

The method for connecting two optical cables (in particular, a distribution cable and a drop cable of an optical access network) using a connection box100comprising the outer casing1and the connection plate5will be now described in detail herein after with reference also to the flow chart ofFIG. 4.

First of all, the operator extracts a distribution fiber60from a distribution cable6(step401).

For this purpose, a first window is cut in the external sheath of the distribution cable6at a first mid-span position thereof and then the distribution fiber60is cut through this first window. Then, a tapping window61is cut in the external sheath of the distribution cable6at a second mid-span position thereof, intermediate between the distribution cable end connected to the distribution cabinet and the first window, possibly in proximity location where end user resides (e.g. on the façade of the user's house). The distribution fiber60is then drawn through the tapping window61.

Then, the operator preferably fixes the distribution cable6to the outer casing1of the connection box100, while the connection plate5is detached therefrom (step402).

For this purpose, the operator preferably arranges the distribution cable6in the base2parallel with the long sides22bof the base2, with the tapping window61completely contained within the inner walls25a,25bof the base2and facing upwardly, as schematically depicted inFIG. 3a. In order to enter and exit the base2of the outer casing1, the distribution cable6engages the recesses23of the short sidewalls22aof the base2. In order to fix the distribution cable6to the base2, the operator may use two collars, each one being wound about the distribution cable6and the tab23aprovided close to each recess23.

The operator then preferably fixes an end of a drop cable7to the connection plate5(step403), while the connection plate5is still detached from the outer casing1.

In particular, the operator preferably removes a length of the sheath of the drop cable7so as to free a corresponding length of a drop fiber70. Then, the operator preferably fixes the end of the sheath of the drop cable7to the first surface5aof the connection plate5by using anyone of the two pairs of protrusions51provided on the connection plate5. Even more particularly, the operator chooses a pair of protrusions51and fits the end of the sheath of the drop cable7between them (as schematically depicted inFIG. 3b), while keeping the drop fiber70exiting from the end of the drop cable sheath on the first surface5aof the connection plate5. Then, the operator winds e.g. a collar about the protrusions51and the sheath of the drop cable7to secure the drop cable7to the connection plate5.

It has to be noted that, at this stage, the operator may fix the drop cable7to anyone of the pairs of protrusions51, without the need to take into account the direction from which the distribution fiber60exits the distribution cable6.

Then, the operator preferably makes the drop fiber70pass from the first surface5ato the second surface5bof the connection plate5(step404).

For this purpose, the operator preferably arranges the drop fiber70on the first surface5aof the connection plate5according to anyone of the two alternative, curved paths defined by the curved guiding walls52and directing walls54and leading from the end of the sheath of the drop cable7to the fiber passage formed by the indentation5cin the perimeter edge of the connection plate5.

For instance, in the configuration shown inFIG. 3c, the operator makes the drop fiber70pass straight along the long side adjacent to the rounded corner where the end of the sheath of the drop cable7is fixed and then turn around the upper curved guiding wall52along a clockwise direction, so as to arrive to the indentation5cfrom a first direction D1. Otherwise, as schematically depicted inFIG. 3d, the operator may make the drop fiber70turn towards the opposite long side of the connection plate5and then follow the lower curved guiding wall52along a counterclockwise direction, so as to arrive to the indentation5cfrom a second direction D2opposite to the direction D1.

If the end of the sheath of the drop cable7were fixed at the other round corner of the connection plate5, it may be appreciated that the operator would have in any case the possibility to arrange the drop fiber70so as to reach the indentation5cfrom anyone of the directions D1and D2. In any case, the operator may advantageously choose the direction D1or D2from which the drop fiber70shall reach the fiber passage formed by the indentation5c(and then the second surface5bof the connection plate5), depending on the direction from which the distribution fiber60exits the distribution cable6.

Then, the operator preferably houses the connection plate5—with the drop cable7fixed thereto as described above—in the outer casing1of the connection box (step405).

For this purpose, the operator preferably turns over the connection plate5so that its first surface5afaces the bottom21of the base2and its second surface5bfaces upwardly. The operator then preferably pushes the connection plate5in the base2—in particular, in the central chamber defined by the inner walls25a,25b—until the pillars55on the first surface5aof the connection plate5fit into the hollow cylinders27of the base2. This way, the connection plate5is completely contained within the central chamber of the base2and is fixed thereto, as shown inFIG. 3e. The operator may then temporarily lean the drop fiber70on the second surface5bof the connection plate5.

If the hollow cylinders27and pillars55are absent (as described above, such attaching members are optional), at step405the operator only arranges the connection plate5in the base2. The connection plate5will be then blocked in the base2at the end of the installation procedure, when the cover3will be closed on the base2.

While the operator inserts the connection plate5in the base2of the outer casing1, she/he preferably keeps the distribution fiber60apart, e.g. she/he may temporarily lean it on the bottom31of the cover3, as schematically depicted inFIG. 3e. When the connection plate5is housed within the base2, the fiber passage formed by the indentation5cin the perimeter edge of the connection plate5is located above the tapping window61of the distribution cable6, from which the distribution fiber60exits the distribution cable6. This allows the operator to bring also the distribution fiber60directly from the distribution cable6to the second surface5bof the connection plate5through the fiber passage formed by the indentation5c(step not shown inFIG. 4), as depicted inFIG. 3e.

As shown inFIG. 3e, the distribution fiber60and drop fiber70exit the fiber passage formed by the indentation5calong opposite directions. This is achieved by choosing the proper arrangement of the drop fiber70between those shown inFIGS. 3c,3d.

It may also be noticed that, in the configuration ofFIG. 3e, the drop cable7enters the base2through one of the recesses24in the short sidewalls22aof the base2. Optionally, the operator may fix the drop cable7to the base2, e.g. by winding a collar about the drop cable7and the tab24aprovided close to the recess24.

Then, the operator preferably connects the distribution fiber60extracted from the distribution cable6to the drop fiber70extracted from the end of the sheath of the drop cable7(step406). For this purpose, the operator preferably uses an optical connector8, such as a mechanical splice or a fusion splice.

The operator then preferably arranges the optical connector8in the connector holder58provided on the second surface5bof the connector plate5(step407). As mentioned above, since the connector holder58keeps the optical connector8in an elevated position above the extra-length of the distribution fiber60and drop fiber70, the optical connector8advantageously acts as a fiber retaining element.

Then, the extra-length of the fibers is arranged on the second surface5bof the connection plate5(step408). In particular, the operator preferably coils such fiber-extra length and arranges it in the peripheral area defined by the perimeter wall56and curved inner walls57provided on the second surface5bof the connection plate5.

The operator finally closes the outer casing1(step409) of the connection box100, as schematically depicted inFIG. 3f. For this purpose, the operator preferably secures the cover3to the base2, by means of the first securing members28and second securing members38provided on the base2and cover3, respectively.

In case the sealing material is in the form of a preformed sealing member (e.g. a rubber preformed sealing member) conformed to fit in the trench26, before securing the cover3to the base2, the operator preferably fits the preformed sealing member in the trench26, thereby providing a hermetically sealing against seepage and dust infiltration.

Accordingly, as illustrated inFIGS. 1a-3f, and5, a connection box (100) for housing a connection between a first optical cable (6) and a second optical cable (7) at a mid-span position of the first optical cable (6) includes an outer casing (1) comprising a first fixing member (23a) configured to fix the first optical cable (6) to the outer casing (1) at the mid-span position; and a connection plate (5) detachable from the outer casing (1) and configured to be completely housed within the outer casing (1).

The connection plate (5) comprises a first surface (5a) comprising a second fixing member (51) configured to fix an end of the second optical cable (7) to the connection plate (5), a second surface (5b) opposite to the first surface (5a) and comprising a connector holder (58) configured to hold an optical connector (8) between a first optical fiber (60) extracted from the first optical cable (6) at the mid-span position and a second optical fiber (70) extracted from the end of said second optical cable (7), and a perimeter edge exhibiting an indentation (5c) which forms a fiber passage configured to allow passage of the second optical fiber (70) from the first surface (5a) to the second surface (5b) of the connection plate (5).

The connection box100is advantageously suitable for façade installations and, at the same time, has a particularly reduced cost.

In the connection box100, indeed, the components needed to hold the optical connector8(as well as those which guide the drop fiber70from the point where it exits the drop cable7to the point where the optical connector8is held and those for arranging the extra-length of distribution fiber60and drop fiber70) are provided on the connection plate5. The outer casing1does not comprise any tab or protrusion, except the fixing member(s)23afor fixing the distribution cable6and the attaching members27. Hence, the outer casing1may have a particularly simple structure with smooth surfaces (no tabs, protrusions, etc.).

On one hand, this implies that the outer casing1can be manufactured (e.g. by plastic molding) at a very reduced cost. Moreover, the connection box100may be provided to the operator with the connection plate5detached from the outer casing1, hence substantially with no assembly cost. The overall cost of the connection box100is therefore reduced, which is particularly advantageous, since the connection box100is intended for a single end user who entirely bears its cost.

On the other hand, the absence of tabs, protrusions etc. from the surfaces of the outer casing1implies the absence of corresponding holes or apertures which would be inevitably formed during the manufacturing by molding. The absence of any hole or aperture on the surfaces of the outer casing1, in combination with the fact that the connection plate5in use is completely housed within it, advantageously provides a box100which may be easily hermetically sealed against seepage and dust infiltration, and which is therefore particularly suitable for façade installation. Protection degrees from water and dust equal to IP-44 (International Protection) may be achieved by coupling the base2to the cover3in a hermetic way, with no need to provide any additional sealing component.

Besides, the operation of connecting the drop cable7to the distribution cable6using the connection box100is particularly operator-friendly, so that it may be carried out even by less experienced operators with a minimum risk of damaging the fibers.

In order to bring the drop fiber70from the point where it exits the drop cable7to the point where the optical connector8shall be held, indeed, the operator only has to make the drop fiber70pass from the first surface5ato the second surface5bof the connection plate5through the fiber passage formed by the indentation5cin the perimeter edge of the connection plate5. This is much easier than making the drop fiber70pass through perimetrically closed apertures or slits.

As to the distribution fiber60, the fiber passage formed by the indentation5cin the perimeter edge of the connection plate5advantageously allows to easily pass also this fiber directly above the second surface5bof the connection plate5, where the connection holder58is provided. This operation may be easily done after the connection plate5has been already fitted into the outer casing1, with no need to make the distribution fiber70pass through any perimetrically closed apertures or slits.