Patent Description:
The present invention relates to telecommunications distribution systems, e.g., optical fiber distribution systems, which may include a rack and elements which populate the rack, wherein such fiber optic elements can include fiber terminations, patching, fiber splitters, and fiber splices.

Optical fiber distribution systems may include fiber terminations and other equipment which is typically rack mounted. Various concerns exist for the optical fiber distribution systems, including density, ease of use and mounting, and cable management. There is a continuing need for improvements in the telecommunications distribution area, especially optical fiber distribution. <CIT>, <CIT> and <CIT> disclose prior art optical distribution systems.

The invention is defined by appended claim <NUM>.

One implementation of a system in accordance with the examples of the disclosure includes a building block element mountable to a rack or other structure. The element includes a chassis and a movable tray. The tray is movably mounted to the chassis with a slide mechanism that allows the tray to slide relative to the chassis, wherein the tray may house equipment for fiber terminations, patching, splitting, and splicing.

The elements can be stacked in a column with each tray slideable in a horizontal direction. In the case of a column of elements, a selected tray is pulled outward to access the desired tray.

In an example embodiment of a fiber optic distribution element, one side of each element can be for patch cables, and the opposite side can be for cable termination of an incoming cable, such as a distribution cable or a feeder cable. The elements can be configured as desired and form building blocks for an optical fiber distribution system. When the elements are mounted in a column in a rack, the cables can be placed in vertical cable guides to enter and exit the selected element. An example rack may be front accessible. However, the elements shown and described can be used in other racks, frames, cabinets, or boxes including in arrangements where rear access is desirable or useful.

According to an aspect of the disclosure, the disclosure is directed to an optical fiber distribution element that includes a chassis defining an interior; a movable tray slidably movable from within the chassis to a position at least partially outside the chassis, the tray defining a front end and a rear end; a slide mechanism which connects the movable tray to the chassis; at least one hingedly mounted frame member within the tray which hinges about an axis perpendicular to the direction of movement of the movable tray; and a cover mounted adjacent the rear end of the tray and movable between an access position and an operational position when the tray is in the open position, only the operational position of the cover allowing the tray to move from the open position to the closed position, the access position allowing access to the at least one hingedly mounted frame member, and the cover in the access position preventing the tray from moving from the open to the closed position.

Referring now to <FIG>, various embodiments of an optical fiber distribution element <NUM> are shown. The element <NUM> can be individually mounted as desired to telecommunications equipment including racks, frames, or cabinets. The element <NUM> can be mounted in groups or blocks which can form a stacked arrangement. In one embodiment, a vertical stack of elements <NUM> can populate an optical fiber distribution rack.

Each element <NUM> can hold fiber terminations or other fiber components including fiber splitters and/or fiber splices.

The example depicted optical fiber distribution element <NUM> that is going to be referenced for describing the inventive features of the disclosure is a drawer-based dedicated splice element that includes, within its tray, cable management structures for guiding cabling to and from hinged splice frames (also referred to herein as splice trays).

As shown, the element <NUM> includes a chassis <NUM> and a movable tray <NUM>. Tray <NUM> is movable with a slide mechanism <NUM>. Slide mechanism <NUM> provides for synchronized movement for managing the cables extending to and from tray <NUM>. Entry points <NUM> on either side of chassis <NUM> allow for fixation of the input and output cables associated with each element <NUM>. U-shaped radius limiters <NUM> associated with each slide mechanism <NUM> move in synchronized movement relative to chassis <NUM> and tray <NUM> to maintain fiber slack, without causing fibers to be bent, pinched, or pulled.

Further details relating to such slide mechanisms that can be used in the distribution element <NUM> are described and illustrated in <CIT>.

Referring specifically to <FIG>, as noted above, the depicted optical fiber distribution element <NUM> that is going to be referenced for describing the inventive features of the disclosure is a dedicated splice element that includes, within its tray, cable management structures for guiding cabling to and from the hinged splice frames.

In the depicted element, incoming outside plant (OSP) cabling <NUM> (e.g., <NUM> micron/<NUM> micron optical fibers) may be directed to pivotally mounted splice frames <NUM> (may also be referred to as splice trays or pivot trays). Within the splice trays <NUM>, each fiber of the OSP cable <NUM> may be spliced to a pigtail <NUM> (i.e., outgoing cabling) that may lead to another element or other points in the network such as other equipment or customer dwellings.

As shown, the incoming cabling <NUM> may follow a path from an exterior of the element <NUM>, through U-shaped movable radius limiters <NUM>, to the interior pivot trays <NUM>. After the splice operation, the outgoing cabling <NUM> may follow a similar path, where the cabling <NUM> is routed through U-shaped radius limiters <NUM> at the opposite side of the elements <NUM>. As shown, the incoming cabling <NUM> may be provided with strength members that are secured to the sides of the elements via cable fixation devices <NUM> such as those described in <CIT>.

Referring now to <FIG>, certain inventive interior features of the trays <NUM> of elements such as the element <NUM> shown in <FIG> will be described.

<FIG> illustrate the details of a cover portion <NUM> of the tray <NUM> that is configured to protect the pivotally mounted splice frames <NUM> provided along a center portion of the tray <NUM>. As shown, the cover <NUM> is hinged adjacent a back end <NUM> of the tray <NUM> and is openable in a front-to-back direction, where the cover <NUM> is pivotally liftable from a front end <NUM> of the cover <NUM>. A flexible latch <NUM> provided at the front <NUM> of the cover <NUM> is used to keep the cover <NUM> closed by being snap-fit into a latch opening <NUM> provided at a front end <NUM> of the tray <NUM>. A latch grip <NUM> can be elastically moved by a user in a front-to-back direction to free a latch lip <NUM> from the latch opening <NUM> before pivotally lifting the cover <NUM>.

The arrangement of the cover <NUM> where the hinge is positioned at the back end <NUM> of the tray <NUM> provides a safety feature for protecting the splice trays <NUM> and the fibers therein within the tray <NUM>. Each of the splice frames or trays <NUM> first must be pivoted down before the cover <NUM> itself can be brought down and snapped to a closed position. When the cover <NUM> is at an open position, slideable closure of the tray <NUM> is prevented by contact of the cover <NUM> with the chassis <NUM> of the distribution element <NUM>. And, since closure of the cover <NUM> requires closure of each of the splice trays <NUM>, accidental closure of the tray <NUM> and pinching or damaging any of the fibers within the splice trays <NUM> is prevented or at least limited.

Without the cover <NUM>, if the tray <NUM> was closed with any of the splice trays <NUM> in an open position, a front edge of the top of the chassis <NUM> of the element <NUM> might damage the trays <NUM> or the fibers therein. To prevent such a closure and the potential resulting damage, cover <NUM> is configured to prevent movement of tray <NUM> to the closed position when cover <NUM> is not in the closed position itself as noted above. The closed position of the cover <NUM> may also be referred to as the operational position, and the open position of the cover <NUM> may be referred to as the access position where the splice trays <NUM> may be accessed.

A hinge <NUM> of the cover <NUM> and a hinge receiver <NUM> of the tray <NUM> may be configured such that the cover <NUM> remains or is locked in an open position when pivoted open. According to one example configuration, the hinge <NUM> of the cover <NUM> may utilize a square or other polygonal shaped cross-section where sharp edges of the cross-section provide temporary stops within the hinge receiver <NUM> to enable the cover <NUM> to remain open when brought to an open position. In such an example, the hinge <NUM> of the cover <NUM> and the hinge receiver <NUM> of the tray <NUM> provide a self-supporting locking system to keep the cover <NUM> in an open position without the need for further structures or features.

As also shown in <FIG>, the cover <NUM> may be used to house a card <NUM> (i.e., identification card) that can be used to write or provide connectivity information thereon regarding the distribution element <NUM>. The card <NUM> is removably mounted to a card slot <NUM> provided on the cover <NUM> via tabs <NUM> provided around the perimeter of the card slot <NUM>. Even though the card <NUM> is removable from the cover <NUM>, the cover <NUM> provides access to the card <NUM> such that distribution information can be written on the card <NUM> without removal from the cover <NUM>.

<FIG> shows the tray <NUM> of <FIG> without the cover <NUM> or the hinged splice frames <NUM> to illustrate the details of inventive cable management structures <NUM> within the tray <NUM>.

As shown, a cable management structure <NUM> is provided at each of the right and left sides <NUM>, <NUM> of tray <NUM>. The cable management structures <NUM> are for guiding cabling to and from the hinged splice trays <NUM>.

According to one example embodiment as depicted, the cable management structure <NUM> may be provided as a removable insert. As such, if the cable management insert <NUM> is damaged in any way, the insert may be replaced with another. In other embodiments, the cable management structure may be integrally molded with the tray of the distribution element <NUM>.

In the depicted embodiment, each cable management insert <NUM> extends in a front-to-back direction, on opposing sides of the flip trays <NUM>. A series of curved radius limiters <NUM> are provided for guiding cabling to and from the splice trays <NUM>.

In the depicted example, each cable management insert <NUM> defines a double layered cable routing channel defined by a lower channel <NUM> and an upper channel <NUM>, wherein cable management fingers <NUM> separate the lower channel <NUM> from the upper channel <NUM>. According to an example configuration as shown in <FIG>, the lower channel <NUM> may be used for <NUM> micron or <NUM> micron optical fibers <NUM> and the upper channel <NUM> may be used for the pigtails <NUM>. The dual layered construction provides a physical separation between two different types of cabling and may provide extra protection to the smaller <NUM> micron or <NUM> micron optical fibers <NUM> in the lower channel <NUM>. As shown, the upper channel <NUM> is also provided with cable retention fingers <NUM> extending into and partially covering the upper channel <NUM> for retaining the pigtails <NUM> within the upper channel <NUM>.

Now referring to <FIG>, details on the locking feature for pivotally mounting the splice frames <NUM> to the tray <NUM> are illustrated.

<FIG> illustrates a prior art version of a locking feature <NUM> provided between a tray such as the tray <NUM> shown in <FIG> and a hinged splice frame <NUM> therein for pivotally mounting the splice frame <NUM> within such a tray <NUM>.

As shown in the example of <FIG>, each frame mounting location <NUM> within the tray <NUM> defines hinge openings <NUM> and a flexible ramped tab <NUM> positioned between the hinge openings <NUM>. Hinge pins <NUM> defined on each splice tray <NUM> are configured to be horizontally slidably inserted into the hinge openings <NUM> while a retention tab <NUM> defined on the splice tray <NUM> slides over and pushes down on the flexible ramped tab <NUM>. Once the flexible ramped tab <NUM> is cleared, the retention tab <NUM> is locked in against a stop surface <NUM> defined by the ramped tab <NUM>. In this manner, the splice trays <NUM> are limited from removal unless the ramped tab <NUM> is flexed down and the hinge pins <NUM> are slid.

<FIG> illustrates an improved version of a locking feature <NUM> according to the claimed invention provided between the tray <NUM> of <FIG> and the hinged splice frames <NUM>. In the version of <FIG>, a flexible ramped tab <NUM> is provided with flexibility along a horizontal plane defined by a bottom surface/wall <NUM> of the tray <NUM>, which is in a perpendicular direction relative to the flex direction shown for the version of the tab <NUM> in <FIG>. As shown in <FIG>, in the improved locking feature <NUM>, the flexible ramped tab <NUM> is provided within an aperture <NUM> defined by the bottom wall <NUM> of the tray <NUM>. Edges <NUM> defining the aperture <NUM> provide positive stops for the flexible ramped tab <NUM> so as to limit over-flexing of the ramped tab <NUM>. In this manner, the flexible ramped tab <NUM> has a limit in its travel and is not as susceptible to breaking off.

In contrast, in the version of the locking feature <NUM> in <FIG>, the flexible ramped tab <NUM> is not limited in its travel since the ramped tab <NUM> is not provided with any positive stops. Thus, repetitive flexing of the ramped tab <NUM> in <FIG> might result in faster deformation or failure of the tab <NUM> versus the ramped tab <NUM> shown in <FIG> which is provided with a positive stop.

Referring now to <FIG>, details relating to example tube holders <NUM> that are configured to be mounted within the tray <NUM> of <FIG> that can frictionally support fiber carrying tubes <NUM> is discussed.

As shown, the tube holders <NUM> may be mounted so as to align with the channels of the movable U-shaped radius limiters <NUM> of the distribution elements <NUM>. The tube holders <NUM> may be configured for tubes holding <NUM> micron fibers or for tubes holding <NUM> micron fibers, depending on the application. The tube holders <NUM> include friction members <NUM> which limit the amount of sliding movement of cables <NUM> passing through the tube holders <NUM>, to assist with cable management. Friction members <NUM> grip lightly on the cables <NUM> in the tube holders <NUM> to reduce or eliminate sliding movement of the cables <NUM> therein.

Such tube holders <NUM> may also be positioned at various locations within the trays <NUM> for guiding of cabling in the preferred paths. As shown in an example layout in <FIG>, one of the tube holders 140a is positioned to lead fiber carrying tubes <NUM> toward the cable management insert <NUM>.

As also shown, a second tuber holder 140b may be positioned and may also cooperate with a channel <NUM> defined at the back <NUM> of the tray <NUM> to lead fiber carrying tubes to an opposite side of the tray <NUM> to provide for a side-switching concept. The second tube holder 140b that is shown to be provided at the rear <NUM> of the tray <NUM> can be mounted at either the right side <NUM> or the left side <NUM> of the tray <NUM> and may bypass the splice frames <NUM> on one side and lead fiber carrying tubes to the opposite side depending upon the connectivity need.

<FIG> illustrates another version of a tray 24b similar to the tray <NUM> of <FIG> that includes a further cable management wall <NUM> on both sides of the tray 24b for guiding cabling within the tray 24b. For example, the cable management walls <NUM> can cooperate with the cable channel <NUM> at the back <NUM> of the tray 24b and guide fiber holding tubes extending from an opposite side of the tray 24b toward the radius limiters <NUM> defined by the cable management insert <NUM> when a side-switching operation is performed. Each cable management wall <NUM> is provided with a cable retention finger <NUM> for retaining the cables.

<FIG> illustrate a retainer <NUM> configured to be mounted within a tray such as the tray <NUM> of <FIG>. The retainer <NUM> is configured to hold a plurality of cable termination units <NUM> in a stacked arrangement. The example retainer <NUM> has the same mounting interface as the above-discussed tube holders <NUM> and can be mounted at various locations within the tray <NUM>. In the depicted embodiment, each retainer <NUM> is shown to hold four cable termination units <NUM> in a stacked arrangement. Other numbers are certainly possible depending upon connectivity need. The cable termination units <NUM> allow termination of cables inside the trays <NUM>. A cable channel <NUM> is defined for receiving the cable. Strength members may be tied down or clamped within each cable termination unit <NUM> for securing the cables.

<FIG> illustrates an example of another cable retention feature <NUM>. The cable retention feature <NUM> is shown to be used at both sides of the tray <NUM> adjacent to the back end <NUM> for transitioning cabling <NUM> (<FIG>) from the U-shaped cable radius managers <NUM> to the main body of the tray <NUM>. In one example, the cable retention feature <NUM> is formed from two flexible fingers <NUM> that provide a push-through design. The flexible fingers <NUM> allow cabling <NUM> surrounded by corrugated tubes <NUM> (i.e., flex tubes) or pigtails to be pushed through and retained thereunder.

Claim 1:
An optical fiber distribution element (<NUM>) comprising:
a chassis (<NUM>) defining an interior;
a movable tray (<NUM>) slidably movable from within the chassis (<NUM>) to a position at least partially outside the chassis (<NUM>), the tray (<NUM>) defining a front end (<NUM>) and a rear end (<NUM>);
a slide mechanism (<NUM>) which connects the movable tray (<NUM>) to the chassis (<NUM>);
at least one hingedly mounted frame member (<NUM>) within the tray (<NUM>) which hinges about an axis perpendicular to the direction of movement of the movable tray (<NUM>); and
a cover (<NUM>) mounted adjacent the rear end (<NUM>) of the tray (<NUM>) and movable between an access position and an operational position when the tray (<NUM>) is in an open position, only the operational position of the cover (<NUM>) allowing the tray (<NUM>) to move from the open position to a closed position, the access position allowing access to the at least one hingedly mounted frame member (<NUM>), and the cover (<NUM>) in the access position preventing the tray (<NUM>) from moving from the open to the closed position;
characterised in that the at least one hingedly mounted frame member (<NUM>) is removably mounted to the tray (<NUM>) via a locking structure (<NUM>),
wherein the locking structure (<NUM>) is defined by a hinge pin (<NUM>) and a spaced apart retention tab (<NUM>) defined on the frame member (<NUM>) and a hinge opening (<NUM>) and a flexible tab (<NUM>) defined on the tray (<NUM>), the hinge opening (<NUM>) configured to receive the hinge pin (<NUM>) in an insertion direction and the flexible tab (<NUM>) configured to elastically flex along a horizontal plane defined by a bottom wall (<NUM>) of the tray (<NUM>) to receive the retention tab (<NUM>) and to provide a stop surface to prevent slidable movement of the retention tab (<NUM>) in a direction that is opposite of the insertion direction of the hinge pin (<NUM>) into the hinge opening (<NUM>), and
wherein the flexible tab (<NUM>) is provided within an aperture (<NUM>) defined by the tray (<NUM>), wherein at least one edge (<NUM>) of the tray (<NUM>) that defines the aperture (<NUM>) is configured to provide a positive stop to limit flexible movement of the flexible tab (<NUM>) along the horizontal plane defined by the bottom wall (<NUM>) of the tray (<NUM>).