Patent Description:
The present invention relates to a cable attachment device for inserting a telecommunication cable containing optical fibers, copper wires or coax cable into a telecommunications enclosure, for example into a terminal closure, pre-stubbed terminal, optical network terminal or other junction box.

Telecommunication cables are ubiquitous and used for distributing all manner of data across vast networks. The majority of cables are electrically conductive cables (typically copper), although the use of optical fiber cables is growing rapidly in telecommunication systems as larger and larger amounts of data are transmitted. Additionally, as data transmissions increase, the fiber optic network is being extended closer to the end user which can be a premise, business, or a private residence.

As telecommunication cables are routed across data networks, it is necessary to periodically open the cable so that one or more telecommunication lines therein may be spliced, thereby allowing data to be distributed to other cables or "branches" of the telecommunication network. At each point where a telecommunication cable is opened, it is necessary to provide a telecommunication enclosure to protect the exposed interior of the cable. The cable branches may be further distributed until the network reaches individual homes, businesses, offices, and so on. These networks are often referred to as fiber to the X (FTTX) networks which can include fiber to the premise (FTTP), fiber to the home (FTTH) and fiber to the antenna (FTTA) networks.

In an FTTH network, optical fiber is brought to the end user and connected to the optical network terminal (ONT) unit mounted on a wall at the end user. The ONT converts this optical signal into conventional electrical signals to provide voice (telephone), Internet (data) and video signals to the end user.

Blown Fiber is a technology used to deploy FTTH in many countries. Protective tubes or ducts are lain in the ground and the fiber-optic cables are then installed by being blown through the protective tube by a medium such as air or water.

Fiber terminals are one type of telecommunication enclosure that is typically located near an end user in a FTTP network to distribute the final service to the end user. Typical fiber terminals are designed to drop services (to provide service connections) to a small number of premises having typically between four to twelve end users. The last service connection from the fiber terminal is made to the ONT, located at the end user using a drop cable. Typically, an optical connector attached to the terminal end of an optical fiber of the cable is preferred to allow quick, reliable field installation.

A first example method of introducing a fiber-optic cable into a telecommunication enclosure is to provide a gas block or water block type connector at or near a wall of the telecommunication closure which separates the cable from the tube through which it is blown, and forms an interface between the cable and the interior of the closure. A protective tube or duct surrounding the fiber-optic cable is fed into one end of the connector and the exposed cable is fed out of the other end of the device and into the closure. This method has a number of drawbacks such as leaving a portion of exposed cable between the connector and the closure which can easily become damaged during routine maintenance work. Connectors known in the art are also bulky and take up a significant amount of space where multiple connections are needed into a closure.

A second example method of introducing a fiber-optic cable into a telecommunication enclosure is to feed a protective tube or duct surrounding a fiber-optic cable directly into a closure. However, with this method, the cable is not fixed relative to the closure. This can lead to movement of the cable within the closure, which can lead to the fibers becoming damaged. Additionally, the sealing between the cable and the tube is not adequate, and moisture can penetrate into the tube.

Therefore, it would be desirable to provide an interface between the tubes, in which the fiber-optic cables are passed, and a terminal closure, pre-stubbed terminal, optical network terminal or other junction box, which is compact and adequately protects and retains the cables.

<CIT> discloses an apparatus for mounting blown fiber tubes, which includes a main housing mountable to an end of a flex tube, an outer ring positioned at an end of the main housing, and an inner ring positioned adjacent to and within the outer ring wherein the blown fiber tubes are positioned about an outer periphery of the inner ring. A trigger pushes the inner ring to compress the blown fiber tubes between the inner ring and the outer ring. The outer ring and the inner ring each include a plurality of spaced pockets each sized for receipt of a blown fiber tube. The trigger includes a threaded member which pushes the inner ring outwardly. In one embodiment, portions of the inner ring separate during activation and press against the blown fiber tubes to compress the blown fiber tubes against the outer ring. A spring may be added to push on the inner ring. Anti-rotation and lock features are provided for the compression, sealing and fixation mechanisms.

In <CIT>, optical fiber cables are installed at an enclosure defining at least one cable port by loading a seal block assembly onto each optical fiber cable; installing and/or connecting a fixation assembly onto each optical fiber cable; and latching the seal block assembly to the enclosure. The cable is secured by the fixation assembly. The fixation assembly retains one or more types of strength members of the optical fiber cable. The seal block assembly snaps and/or clips into a locked position relative to the enclosure. A filler rod can be used to fill an unused port in the seal block assembly. An attachment device can be used to connect to the filler rod for adding a new tube to the seal block assembly.

The invention is defined in the independent claim, to which the reader is now directed. Preferred or advantageous features are set out in the dependent claims.

According to a first aspect, a cable attachment device for sealing and retaining a communications cable entering a telecommunications closure through an opening defined in the closure is provided, the device comprising a housing, having a passage through which the communications cable extends, the housing having a first portion and a second portion; wherein the first portion of the housing is configured to receive a protective tube of the telecommunications cable; wherein the second portion of the housing is configured to engage with the closure; a first seal configured to form a seal between the device and the closure; a second seal configured to form a seal between the interior of the device and the protective tube; a third seal configured to seal between the communications cable and the interior of the device wherein the third seal circumscribes the communications cable; a first retaining arrangement configured to couple the device to the closure; a second retaining arrangement configured to hold the tube relative to the device; and a third retaining arrangement configured to fix the telecommunications cable relative to the device, wherein the first portion comprises an inlet portion for insertion in the telecommunications closure, and the second portion comprises a locknut portion and a gasblock portion; an end of the inlet portion comprises a compressible member, and wherein the third seal is configured to be received in a bore of the compressible member; and the inside of the locknut portion is shaped such that it exerts a force on the compressible member of the inlet portion to compress the third seal when the locknut portion is coupled to the inlet portion, forming the seal between the communications cable and the interior of the device.

This arrangement provides the advantages of a gas block or water block type connector with those of a direct connector into a closure. In particular, this device provides a watertight solution which seals between the closure and the device, between the device and the tube and between the tube and the cable housed within. The device also prevents unwanted movement of the tube and cable by fixing both the tube and the cable within the device which can lead to damage of the fibers or other components. The second retaining arrangement which retains the tube within the device provides the advantage of the tube being able to remain in place if the cable needs to be replaced. The second portion may be partially received in the closure. Alternatively, the second portion may be fully received in the closure. The second retaining arrangement may still permit some movement of the tube relative to the device, such as rotational movement.

Optionally, the first seal circumscribes an outer surface of the second portion of the device housing.

This arrangement can advantageously enable good sealing between the device and the closure as it is the second portion of the device which is received in the opening of the closure. Providing the seal on an outer surface of the device rather than in the opening of the closure can help to make routine maintenance operations easier for an operator. This is because the seal can be more easily replaced in case of failure. Additionally, the cable attachment devices are intended to be replaced more often than a closure, meaning that the seal is replaced more frequently. Providing the seal as an integral part of the attachment device also reduces the operations needed to be made by an operator assembling the device in the closure.

Optionally, the second seal circumscribes the protective tube.

Optionally, the passage of the first portion of the housing is configured to receive the second seal.

Optionally, the first retaining arrangement is arranged on the second portion of the device housing.

With this arrangement, when the device and the closure are connected, the retaining arrangement is received in the closure. This has the advantage of the retaining arrangement being more secure and less likely to be unintentionally disengaged when other attachment devices are being connected or disconnected.

Optionally, the first retaining arrangement comprises one or more resilient members that releasably engage with the closure.

This can allow the attachment device to be releasably connected to the closure. This can make assembly and disassembly easier, as well as providing an operator with more options for routine maintenance operations.

Optionally, the passage of the first portion of the housing is configured to receive the second retaining arrangement.

Optionally, the second retaining arrangement releasably engages with the tube.

This can allow the tube to be removed if replacement of the tube or attachment device is required.

Optionally, when the second retaining arrangement is engaged, removal of the tube is not possible.

Optionally, when the second retaining member is engaged, the tube is able to rotate relative to the device.

This can advantageously allow the attachment device to be rotated in the closure without creating torsion in the tube. This is also advantageous for the assembly of the attachment device, where portions of the device have threaded connections and rotation of the portions is required.

Optionally, the device further comprises a second retaining member release mechanism which is configured to disengage the second retaining arrangement.

Optionally, when the second retaining arrangement is disengaged removal of the tube from the device is possible.

Optionally, the second retaining arrangement comprises a plurality of spaced apart resilient fingers.

Optionally, the protective tube is a duct for blown fiber and the communications cable is installed by being blown through the protective tube by a medium such as air or water.

Whenever possible, like reference numbers will be used to like components or parts.

<FIG> is an exploded view of an exemplary cable attachment device <NUM> according to an embodiment of the invention. The cable attachment device <NUM> housing has a first portion <NUM> and a second portion <NUM>. The first portion <NUM> of the housing is configured to receive a protective tube of a telecommunications cable and the second portion of the housing is configured to engage with a telecommunications closure (not shown). The cable attachment device can also be divided into an inlet portion <NUM>, a locknut portion <NUM> and a gasblock or waterblock portion <NUM>. The inlet portion <NUM>, locknut portion <NUM> and gasblock or waterblock portion <NUM> each have a respective central bore or passage. The device <NUM> has a first seal <NUM> on an outer surface of the inlet portion <NUM>, configured to form a seal between the device <NUM> and the telecommunications closure. The first seal <NUM> is in the form of a gasket. The device <NUM> has a second seal <NUM> received in the gasblock or waterbock portion <NUM>, configured to form a seal between the interior of the device <NUM> and the protective tube of the communications cable to be received in the device <NUM>. The second seal <NUM> is in the form of a gasket. The device has a third seal <NUM> received in an end of the inlet portion <NUM>, configured to seal between the communications cable and the interior of the device <NUM>. The end of the inlet portion <NUM> has a number of resilient arms <NUM> that circumscribe the third seal <NUM> when it is inserted in the end of the inlet portion <NUM>. The third seal <NUM> is in the form of a gasket. The device <NUM> further has a first retaining arrangement <NUM> configured to couple the device to the closure; a second retaining arrangement (not shown) configured to hold the tube relative to the device <NUM>; and a third retaining arrangement <NUM> configured to fix the telecommunications cable relative to the device <NUM>. The first retaining arrangement <NUM> is on the inlet portion <NUM> which is partially received in an opening of the closure, and is in the form of two resilient arms. The second retaining arrangement is received in the gasblock or waterblock portion <NUM> of the device <NUM>. The second retaining arrangement will be described in more detail in relation to <FIG>. The third retaining member <NUM> is on the inlet portion <NUM> of the device <NUM> and is a clamp in this example. The third retaining member <NUM> will be described in more detail in relation to <FIG>.

<FIG> respectively show cross-sectional views of an assembled and exploded view of the locknut portion <NUM> and gasblock or waterblock <NUM> portion of the device <NUM>. In these views, the second retaining arrangement <NUM> can be seen. In this example the second retaining arrangement <NUM> is in the form of a ring with a plurality of resilient fingers which are configured to engage with the protective tube of the cable. An intermediate piece <NUM> is shown which helps to keep the second seal <NUM> in place in the gasblock or waterblock portion <NUM>. A guide assembly <NUM> comprising a first guide piece 33a and a second guide piece 33b is shown which guide the tube into the gasblock or waterblock portion <NUM>. These also help to retain the second retaining arrangement <NUM> in place in the gasblock or waterblock portion <NUM> and form the second retaining arrangement <NUM> release mechanism. A user can push on the second guide piece 33b to deform the resilient fingers of the second retaining arrangement <NUM> and disengage them from the protective tube of the cable. The gasblock or waterblock portion <NUM> also has a mechanical stop <NUM> in the form of a narrowing of the central passage of the gasblock or waterblock portion <NUM>. This mechanical stop <NUM> serves to stop the tube and prevent the tube from passing completely through the gasblock or waterblock portion <NUM>.

<FIG> show a perspective view of an example intermediate piece <NUM>. <FIG> show another example of the intermediate piece <NUM> with an additional ring <NUM> which creates a uniform surface at the end of the intermediate piece <NUM> and helps to locate the second seal <NUM>.

<FIG> show perspective views of the locknut <NUM> and gasblock or waterblock portion <NUM> at different stages of assembly. The tube <NUM> is inserted into an opening in the guide assembly <NUM>, passes through the intermediate piece <NUM>, the second retaining arrangement <NUM> and the second seal <NUM> and abuts the mechanical stop <NUM>.

<FIG> show perspective views of an example cable <NUM> being assembled in the locknut <NUM> and gasblock or waterblock portion <NUM>. <FIG> shows the cable <NUM> being blown through the tube <NUM> in a medium such as air or water. <FIG> shows the third seal <NUM> being placed over the cable <NUM> such that it circumscribes the cable. <FIG> shows the cable <NUM> with the third seal <NUM> in place. A portion of the cable outer sheath which has passed through the locknut <NUM> and gasblock or waterblock portion <NUM> is stripped back to expose the fibers <NUM> and a strength member <NUM> therein. The strength member <NUM> can be cut down such that only a short length protrudes from the outer sheath of the cable <NUM>.

<FIG> show perspective views of an example inlet portion <NUM> being assembled with the locknut portion <NUM> and gasblock or waterblock portion <NUM>. <FIG> shows the cable <NUM> and exposed fibers <NUM> and strength member <NUM> of <FIG> being passed through the inlet portion <NUM>, and the third seal <NUM> being inserted into the central bore of the inlet portion <NUM>. <FIG> shows the inlet portion <NUM> assembled to the locknut portion <NUM> and gasblock or waterblock portions <NUM> with an external thread of the inlet portion <NUM> engaged with an internal thread of the locknut portion <NUM>. <FIG> shows the third retaining arrangement <NUM> assembled to the inlet portion <NUM> and the strength member <NUM> of the cable retained by this third retaining arrangement <NUM>. In this example, the third retaining arrangement <NUM> is a clamp. In this Figure, the cable is fully assembled in the cable attachment device.

<FIG> is a sectional view of the fully assembled configuration of <FIG>. This view reveals how the third seal <NUM> engages with the cable <NUM> to seal between the tube <NUM> and inside the cable <NUM>. The inside of the locknut portion <NUM> is shaped such that it exerts a force on the resilient arms <NUM> of the inlet portion to compress the third seal <NUM>. This helps to retain the cable and create the seal between the tube <NUM> and the inside of the cable <NUM>.

<FIG> show a second embodiment of the locknut and gasblock or waterblock portions at different stages of assembly with a tube. <FIG> is an exploded view of the locknut and gasblock or waterblock portions in which the two portions are separate components. In this example, there is no intermediate piece to hold the second seal <NUM> in place. In this example, the second seal <NUM> is placed in between the separate locknut portion <NUM> and gasblock or waterblock portion <NUM> and held in place by the threaded engagement of the locknut portion <NUM> with the gasblock or waterblock portion <NUM>. In this example an additional seal <NUM> is provided to seal between the body of the locknut portion <NUM> and the tube <NUM>. The gasblock or waterblock portion <NUM> of this example also has a mechanical stop <NUM> to stop the tube <NUM> from being passed through. <FIG> is an assembled perspective view of the locknut portion and gasblock or waterblock portion of <FIG>. <FIG> shows the assembled locknut portion <NUM> and gasblock or waterblock portion <NUM> of <FIG> with a tube <NUM> installed. <FIG> shows the assembled locknut portion <NUM> and gasblock or waterblock portion <NUM> of <FIG> with a cable installed and stripped in the same way as is described in relation to the example of <FIG>.

<FIG> show perspective views of the second embodiment of the locknut portion <NUM> and gasblock or waterblock portions <NUM> at different stages of assembly with an inlet portion <NUM>. The steps of the installation of the inlet portion <NUM> described in relation to <FIG> correspond respectively to the steps of <FIG> and, for brevity will not be repeated. The strength member <NUM> of the cable is omitted from these Figures for simplicity but it will be appreciated that a strength member similar to that of <FIG> could also be present in this embodiment.

<FIG> show a cable attachment device <NUM> according to the second embodiment, being installed in a closure <NUM>. <FIG> shows a cable attachment device <NUM> being installed in a closure <NUM>. A portion of a closure wall <NUM> is shown, with an opening <NUM> configured to receive the first portion of the cable attachment device. The first retaining arrangement <NUM> is configured to engage with an inner surface of the wall <NUM> of the closure to retain the cable attachment device <NUM>, to retain the device in the closure <NUM>. <FIG> shows the cable attachment device <NUM> coupled to the closure <NUM>. <FIG> is a cross sectional view of a cable attachment device <NUM> installed in a closure <NUM>. This view shows how the first seal <NUM> forms a seal between the device <NUM> and the closure <NUM>. <FIG> is a perspective view showing a portion of a closure with a number of cable attachment devices <NUM> installed in openings <NUM> in the closure <NUM>.

<FIG> show another example of the second embodiment of the invention in which the locknut portion <NUM> and the gasblock or waterblock portion <NUM> are separate but configured to be permanently joined together by ultrasound welding or another suitable joining method. In this example, the locknut portion has an energy director <NUM> to focus the ultrasonic energy during ultrasonic welding to facilitate joining of the locknut portion <NUM> and the gasblock or waterblock portion <NUM>.

<FIG> show a third embodiment of the locknut portion <NUM> and gasblock or waterblock portion <NUM> at different stages of assembly with a tube <NUM>. In this third embodiment, the second seal <NUM>, provided between the inside of the tube <NUM> and the cable <NUM> is in the form of a plug configured to be mounted to the end of the tube <NUM> and the second seal <NUM> has a channel through which the cable <NUM> can be passed. In this example, the locknut portion <NUM> and the gasblock or waterblock portion <NUM> form a single component. The second seal also has a flange <NUM> which engages with a mechanical stop <NUM> in the gasblock or waterblock portion <NUM> to stop the tube <NUM> from being passed through. This embodiment shares most of the features of the second embodiment and, for brevity, these will not be repeated.

<FIG> show various views of a third embodiment of the locknut portion and gasblock or waterblock portion being assembled with the inlet portion. These figures show that the locknut portion <NUM> and gasblock or waterblock portion <NUM> of the third embodiment is assembled with the inlet portion <NUM> in the same way as is described in respect of the first and second embodiments.

Claim 1:
A cable attachment device (<NUM>) for sealing and retaining a communications cable entering a telecommunications closure (<NUM>) through an opening defined in the closure, the device comprising:
a housing having a passage through which the communications cable (<NUM>) extends, the housing having a first portion (<NUM>) and a second portion (<NUM>);
wherein the first portion (<NUM>) of the housing is configured to receive a protective tube (<NUM>) of the telecommunications cable;
wherein the second portion (<NUM>) of the housing is configured to engage with the closure;
a first seal (<NUM>) configured to form a seal between the device and the closure;
a second seal (<NUM>) configured to form a seal between the interior of the device and the protective tube;
a third seal (<NUM>) configured to seal between the communications cable (<NUM>) and the interior of the device, wherein the third seal (<NUM>) circumscribes the communications cable (<NUM>);
a first retaining arrangement (<NUM>) configured to couple the device to the closure;
a second retaining arrangement (<NUM>) configured to hold the protective tube (<NUM>) relative to the device; and
a third retaining arrangement (<NUM>) configured to fix the communications cable (<NUM>) relative to the device;
wherein the second portion (<NUM>) comprises an inlet portion (<NUM>) for insertion in the telecommunications closure (<NUM>), and the first portion (<NUM>) comprises a locknut portion (<NUM>) and a gasblock portion (<NUM>);
an end of the inlet portion (<NUM>) comprises a compressible member (<NUM>), and wherein the third seal is configured to be received in a bore of the compressible member (<NUM>); and
the inside of the locknut portion (<NUM>) is shaped such that it exerts a force on the compressible member (<NUM>) of the inlet portion (<NUM>) to compress the third seal (<NUM>) when the locknut portion (<NUM>) is coupled to the inlet portion (<NUM>), forming the seal between the communications cable and the interior of the device.