Telecommunications closures

An optical fiber enclosure for a pedestal environment includes a pedestal which slideably supports a closure within the pedestal along a vertical direction so that during freeze-thaw envionrmental conditions when the pedestal is raised and lowered by expanding and contracting earth the closure does not impose undue stress on optical fiber cables connected thereto. Another enclosure suitable for buried applications also includes means for slideably extending an inner closure therefrom along a vertical direction to aid a craftsperson in accessing and working on the inner closure, the buried enclosure including means for allowing one or more loops of telecommunications cable to be stored therewithin for allowing the inner closure to be removed a substantial distance therefrom.

CROSS-REFERENCE TO RELATED APPLICATIONS 
The present application is related to copending application Ser. No. 
07/439,898 entitled "Card Cage" invented by Allen et al. now pending being 
filed concurrently herewith and assigned to the assignee of the present 
invention, the disclosure of which is incorporated herein by reference, 
that application disclosing and claiming various novel features of a card 
cage illustrated in FIGS. 7-10 hereof, that card cage being preferably 
useable in preferred closure embodiments illustrated in FIGS. 1-6 hereof, 
the particular closure embodiments being that which is claimed in the 
present application. 
BACKGROUND OF THE INVENTION 
The present invention relates to improved environmental closure 
constructions and accessories useable for environmentally protecting 
communication cables, preferably optical fiber cables. 
In recent years optical fiber communication networks have gained wide 
acceptance as opposed to the use of alternate electrical cable systems due 
to the significantly enhanced bandwidth capabilities available for optical 
fiber and its immunity to electromagnetic and radiomagnetic interference. 
Though very significant advantages are achievable by the use of optical 
fiber rather than electrical conduction media, a continuing problem with 
the deployment of optical fiber systems relates to how optical fiber 
cables can be terminated so as to make electrical or optical connections 
to fibers within the cables and yet adequately environmentally protect the 
cables and allow for craft friendly installation. 
The present invention is directed to various improved constructions for 
facilitating the termination of optical fiber cables, optically connecting 
fibers within the cables, protecting optical fibers not to be optically 
coupled at a subscriber drop point, and environmentally sealing the 
optical fiber cable after it has been entered for coupling or breakout 
purposes. 
SUMMARY OF THE INVENTION 
Accordingly it is an object of the present invention to provide novel and 
superior means for enclosing telecommunication cables in a easy and 
convenient manner. 
These and other objects of the invention are achieved by the provision of 
preferred embodiments of a pedestal enclosure and a buried enclosure. 
Novel and advantageous features of the invention include the provision of a 
pedestal which includes means for slideably supporting a closure 
therewithin along a vertical direction relative to the pedestal so that 
during freeze-thaw environmental conditions when the pedestal is 
physically moved in the vertical direction by an expanding and contracting 
ground surface no excess stress is applied to the telecommunication cable 
connected to the closure. 
A further advantageous feature of the invention is the provision of means 
for holding first and second segments of a telecommunications cable to be 
entered outside an entrance and exit location of the closure used for 
sealing an entered portion of the cable so that a craftsperson can easily 
work on the entered cable section. 
A further feature of the invention is the provision of a novel and 
advantageous terminal block layout which allows drop wires to be 
conveniently and easily connected to and disconnected from a terminal 
block. 
Yet a further feature of the invention is the provision of a closure, 
preferred for buried application, which has a space capsule type 
appearance comprising three adjacent sections the bottom of which is 
substantially cylindrical in shape, the middle section of which is 
substantially conical in shape, and the upper portion of which is 
substantially cylindrical in shape and has a cylindrical diameter about 
one-third that of the lowest section. The lowest or bottom section has 
entrance and exit channels along a wall thereof aligned such that a cable 
can enter and exit the enclosure along a direction substantially tangent 
to its cable entrance and exit points, the bottom section being sized so 
as to be able to accommodate one or more loops of optical fiber cable such 
that a minimum bend radius of the cable is not exceeded. A first closure 
housed within the space capsule shaped second closure includes means for 
being vertically extendable above the upper surface of the buried second 
closure so as to allow a craftsperson easy and convenient access to the 
inner first closure, the circumferential loops of the cable stored within 
the buried closure allowing the first enclosure to be so raised.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a first preferred embodiment of the invention. This 
figure illustrates a pedestal optical fiber closure 1 which includes a 
pedestal 2 which normally encases and encloses an optical fiber closure 4, 
a preferred construction of the closure 4 being further described in U.S. 
application Ser. No. 06/721,527, abandoned in favor of U.S. Ser. No. 
110,051, abandoned in favor of U.S. Pat. No. 4,913,522, the disclosure of 
which is incorporated herein by reference. The pedestal includes a front 
upper cover, which exposes the closure 4 when removed. First and second 
optical fiber cable sections 6, 7 of fiber cable 5 are preferably held in 
place by optical fiber cable holder 8 which is preferably attached to a 
slideable bracket 10 which has an end face 11 which can slide in a 
vertical direction within channel 12 located on opposite sides of the end 
face 11. The holder 8 is preferably a hard rubber material member with 
first and second apertures 16, 17 which clamp onto and hold the cable 
sections 6, 7. In FIG. 1, a side portion of the pedestal is shown broken 
away and the top front cover therefor has been removed to show the 
contents within the pedestal. The cable sections 6, 7 and 5 are of the 
type that comprise a plurality of sheaths and preferably at least one 
shield, the cable having an internal longitudinal strength which is 
sufficient to normally support the vertical weight of the holder 8, the 
cable seal 9, the closure 4, the bracket 10, as well as the cable sections 
5, 6, 7 within the pedestal 2; the internal longitudinal strength of the 
cable being aided of course by frictional engagement between the end face 
11 and the channels 12. 
In use, the pedestal optical fiber closure 1 normally rests on the ground, 
and the optical fiber cable sections 6, 7 enter the closure 1 from beneath 
a closure bottom surface 14. Preferably, prior to entering and connecting 
couplers to optical fibers within the cable sections 6, 7 and securing the 
couplers within the closure 4, the first and second cable portions 6, 7 
are secured to the holder 8 and held by the bracket 10 to facilitate 
working with the cable by a craftsman. Thereafter, a portion of the cable 
is stripped of its sheath and shield layers and communication media 
therewithin, e.g. optical fibers or electrical wires, are separated and 
coupled to and the stripped cable portion is then entirely sealed within 
the closure 4. After appropriate coupling is accomplished with fibers or 
wires within the cable sections 6, 7 and the closure 4 is assembled and 
sealed, the slideable bracket 10 allows the pedestal optical fiber closure 
1 to reliably protect the cable 5 in freeze/thaw environmental conditions. 
More specifically, in colder months when a ground level beneath the 
pedestal bottom surface 14 freezes, the pedestal is normally urged upward 
very gradually over time in a vertical direction. Since the optical fiber 
closure 4 is totally supported by the slideable bracket 10 and holder 8, 
the pedestal 2 is allowed to move vertically relative to the closure 4 so 
as to prevent any undue stress or strain being induced to the fiber cable 
5 as the pedestal 2 rises during a freezing period and alternatively falls 
during a thawing period. 
FIG. 2 illustrates an alternate embodiment of the invention whereby 
reference numeral 21 illustrates a buried optical fiber closure. According 
to this embodiment, upper closure face 22 is intended to be substantially 
coplanar with a ground surface and preferably has holes 19 therein for 
aiding in removing the upper closure face. A remainder of the closure 21 
is hence intended to be beneath ground level. 
An optical fiber cable 5 enters the closure 21 through a tubular inlet 24 
which has an opening which is essentially tangential to a circumferential 
surface 26 of the closure 21. Similarly, tubular outlet 28 has an end 29 
which extends along a direction which is essentially tangential to the 
circumferential surface 26 which allows the cable 5 to exit the closure 
21. Between entering the closure 21 via the inlet 24 and exiting via the 
outlet 28, the cable 5 is allowed to freely loop around an interior 
section of the circumferential surface 26, with cable sections 6, 7 
extending upward within the closure so as to be enclosed by the closure 4. 
Again, as in the embodiment of FIG. 1, a cable holder 8 is preferably used 
for holding the first and second cable sections 6, 7 to facilitate working 
on an intermediate cable section prior to enclosing same within the 
enclosure 4 during cable installation. In this embodiment, normal 
gravitational support for the closure 4 is provided by the interengagement 
of a lower substantially flat surface 25 of a handle 30 and an upper 
substantially flat surface of a back member 38 which interconnects rails 
32, the handle 30 being shown only in FIG. 2 and omitted in FIG. 3 for 
purposes of clarity. Accordingly, to vertically raise the closure 4 from 
the closure 21, a craftsman simply grabs the handle 30 with his fingers 
and lifts upward thus causing plate 31 to slide within rails 32. 
Preferably, the closure 21 has holes (not shown) for drop cables to enter 
and exit at any convenient location. 
To facilitate working on this intermediate cable section during a field 
installation procedure, according to the invention the closure 4 is 
slideable mounted to the closure 21 via the slideable plate 31 which is 
slideably within the closure rails 32, the plate 31 being secured to the 
closure 4, as illustrated in FIG. 3. Accordingly, to easily work on the 
closure 4 all a craftsman needs to do is raise the closure 4 vertically 
due to the sliding interengagement of the plate 31 and rails 32 so that 
the closure 4 resides an appropriate distance above ground level, and 
secure the closure 4 thereat with a suitable pin 35 disposable in pin slot 
36 or other support means, as illustrated in FIG. 4, a part of the pin the 
being wedges against the member 38. As illustrated in FIG. 2, preferably 
the buried optical fiber closure 21 includes a substantially cylindrical 
section 33 which rests above and is integrally connected with a 
substantially conical section 34 which is connected to a cylindrical base 
section 39. 
FIGS. 5 and 6 illustrate two perspective views of a preferred terminal 
block construction illustrated in FIGS. 1 and 2. According to these 
figures, a terminal block 41 includes first and second sets of terminals 
arranged in rows and located adjacent to opposite side ends of the 
pedestal or closure, e.g. either the pedestal closure 1 or the buried 
closure 21. Preferably, each terminal set 42, 43 includes first and second 
adjacent rows of terminals, as illustrated, with the rows being recessed 
relative to one another, as illustrated. Such a construction allows for, 
in the example illustrated, 16 terminal connections to be made with the 16 
individual terminals 44 for connecting to electrical dropwires which are 
connected within the closure 4. Stacking and offsetting the sets of 
terminals as illustrated allows the terminals to be most easily accessible 
to a craftsman while allowing minimum interference to occur between the 
closure 4 and the various terminals 41 so as to facilitate installation 
and connection of the closure 4. Alternate placement of the terminals is 
possible, one such location would be adjacent the base plate 48 and the 
terminals could be connected to the base plate as well. 
Referring back to FIG. 1, the closure 4 includes a dome 47 connectable to 
the closure base plate 48. Within the dome 47, as illustrated in FIG. 7, 
is contained card cage 51, preferably for housing optical and electrical 
components, the cage being releasably securable to the base plate 48 via 
engageable and disengageable spring clamp tines 52 which have a 
longitudinal slit 53 near an upper end thereof which is engageable with a 
protruding rail 55 which protrudes from opposite sides 56, 57 of the card 
cage 51. According to this construction, the card cage 51 and tines 52 are 
sized such that the tines 52 must be resiliently urged outward away from 
each other to allow the card cage rails 55 to ride over and down an inner 
side surface 57 of the spring clamps 52. The rails 55 mate within the 
longitudinal slits 53 near the top of the tines 52, the tines being guided 
by channels formed on exterior surfaces of the card cage housing. 
Accordingly, this construction allows for the card cage 51 to be easily 
attachable to the closure base plate 48 without requiring the use of 
bolts, screws, or other cumbersome items by a craftsman. 
A further novel feature of the card cage 51 is the provision of integrally 
molded spring clamps 61, 62 preferably located on one of the sides 56, 57 
of the card cage at an upper end thereof, as illustrated in FIG. 7. The 
card cage 51 has a plurality of opposing vertically oriented longitudinal 
channels 64 which slideably guide and hold various boards or cards 65 
within the card cage 51. Each card or board 65 can preferably have mounted 
thereon electronic and/or optical circuitry and power modules as necessary 
for operation of various electro-optical components to be housed within 
the card cage 51. Specifically, according to a preferred embodiment, 
boards 65 could have mounted thereon circuitry for providing 
digital-to-analog and analog-to-digital operations, power and power 
conversion operations, packet assembly and disassembly functions, etc. 
Upper side ends 66 of the spring clamps 61, 62 are precisely positioned 
over an approximate top of longitudinal channels 64 so as to normally 
contain the cards 65 within the channels 64 and keep them from being 
inadvertently removed from the card cage 51. Upon sidewards deflection of 
the spring clamps 61, 62 along a direction of the arrows 67 an end 65 of 
the spring clamps 61, 62 is deflected off center from an upper edge of its 
respective longitudinal channel 64 so as to allow a board 65 to be 
inserted or removed from its respective longitudinal channel pair 64. 
Since the spring clamps 61, 62 are integrally formed by molding with a 
material which otherwise forms the housing of the card cage 51, the 
described construction provides for a cost efficient closure which is 
easily manufacturable and which is easily useable by a craftsman since use 
of external removeable clamps is not required, or any other separate 
securing or clamping means for that matter which can easily be dropped. 
FIG. 8 shows yet further features of the invention, this figure showing the 
card cage 51 in an attitude whereby an end face 70 has been deflected from 
a body of the card cage. As FIG. 9 shows, the end face 70 comprises a tray 
71 which contains an optical fiber or fiber tube storage surface 72 
thereon for accommodating and storing bare optical fibers or optical 
fibers housed loosely within tubes 73, the bare fibers or loose tube 
fibers not being optically or electrically connected to components within 
the card cage 51. Hence, these fibers and/or tubes are expressly routed. 
In the embodiment of FIG. 9, a loose tube fiber configuration is actually 
illustrated, these tubes being typically used in optical fiber cable 
constructions of the type wherein the fibers are loosely contained within 
tubes which are then environmentally sealed by various cable layers 
therearound. Other typical optical fiber cable constructions, such as a 
slotted core type, contain bare optical fibers typically helically wound 
within slots of a core of a cable, the slots and fiber then being 
environmentally sealed by various cable layers therearound. In either 
case, the card cage 51 is useable with such cables, and in the case of the 
loose tube cable type, it preferably would be the loose tubes which are 
expressly routed within the surface 72 of the tray 71; and in the case of 
the slotted core cable it would be bare buffered fibers which are routed 
within the surface 72 of the tray 71. Optionally, with bare fibers from a 
slotted core, the express fibers could be stored in coupler tray 86. A 
typical optical fiber cable may contain somewhere of the order of 10-200 
individual fibers therein, and it may only be desirable or necessary to 
optically couple to only a fraction of the fibers within the cable. 
Accordingly, fibers or fiber tubes not optically coupled to need to be 
routed within the closure 4 in a easily convenient manner, which is a 
function of the storage tray 71. In addition, the tray 71 could hold fiber 
splices, connectors, etc. 
Another particularly advantageous feature of the storage tray 71 is the 
provision of essentially a plurality of horizontally aligned ribs or 
corrugations 75 which are separated from one another in a vertical 
direction as illustrated in FIGS. 7-9. The corrugatins are sized and 
spaced such that upon deflecting an upper part 76 of the storage tray 71 
away from an upper part 77 of the card cage as illustrated in FIG. 9, a 
minimum bend radius of any fibers or fiber tubes being expressly routed 
within the storage tray 71 is not less than a minimum bend radius 
specified for the optical fibers. The parallel ribs thus form an elongated 
flexible and resilient hinge. Preferably, the storage tray 71 further 
includes an outer concave shaped cover 78 which further protects the 
fibers or tubes 73, the outer cover 78 preferably but not necessarily 
being transparent. 
A further advantageous feature of the storage tray is the provision of an 
integrally molded and formed attaching member 80 which has a hook end 81 
which can snap attach to a body of the card cage 51 and keep the storage 
tray secured thereto so as to form an environmental dust cover for an 
optical coupler tray 86. Another feature of the storage tray 71 is the 
provision of a second attaching member 82 which has a bottom end 83 (FIG. 
7) which has a T-construction which is engageable with a mating T-slot 84 
formed in a bottom surface of the card cage 51. Optionally, the slot 84 
could be an aperture in the wall of the card cage rather than in a side 
edge thereof. The provision of the second attaching member 82 allows the 
storage tray 71 to be positively and naturally secured in an open position 
so as to allow a craftsman easy and convenient access to the optical 
coupler tray 86 when installing optical fibers therein as to be further 
explained below. After the optical fibers to be coupled are appropriately 
mounted within the optical fiber coupler tray 86, the T-shaped bottom end 
83 is disengaged from its T-slot 84 and the hooked end 81 of the attaching 
member 80 is firmly secured to the card cage body so as to environmentally 
seal the optical coupler tray 86. A preferred construction of the member 
82 and mating slot 84 is to allow the storage tray to be passively rotated 
and held away from the card cage body by an angle in excess of 45.degree., 
50.degree., 60.degree., 75.degree.; at least in excess of 30.degree. or 
40.degree., relative to a vertical axis of the card cage, with the hinge 
resiliently urging the tray 71 toward the tray 86 and towards an express 
fiber storage attitude where the angle is thus 0.degree.. Optionally the 
angle is about 75.degree.. 
The optical coupler tray 86 includes a plurality of optical coupler modules 
87 on which are mounted one or more optical couplers 88. Preferably, the 
optical couplers have a construction as described in copending application 
Ser. No. 07/344,778 and assigned to the assignee of the invention, the 
disclosure of which is incorporated herein by reference. Specifically, 
preferably the couplers couple light between an electro-optic transducer, 
e.g. emitter or detector, and a core of a fiber by passing the light 
through a side of a fiber cladding and buffer. Optical fibers 90 which are 
to be optically coupled are inserted into an appropriate optical coupler 
88 so as to form a bend in the optical fibers 90 which allows light to 
either be coupled into or coupled out of a core of each coupled optical 
fiber, as more fully explained in U.S. application Ser. No. 344,778, a 
bend radius within the coupler being far less than a minimum bend radius 
of the fiber, e.g. typically in the range of 2 mm to 15 mm. Preferably, a 
plurality of attachment sections 91 are provided which can accommodate 
optical fiber connectors or optical fiber splices which may be formed in 
the optical fibers 90 as can be necessary if one or more optical fibers 90 
are inadvertently broken and thus required to be spliced or connected. 
FIG. 10 illustrates yet a further feature of the invention whereby a bottom 
surface 58 of the card cage 51 has a plurality of electrical test pins 93 
extending in three adjacent vertical rows and extending from the bottom 
surface 58. Additional electrically connecting pin sets 94 are provided, 
these being engageable with mating electrical pin connectors 95 disposed 
on an upper surface of the base plate 48. Accordingly, when the card cage 
51 is attached to the base plate 48, the electrical pin sets 94 mate with 
the electrical pin connectors 95 and provide electrical communication to a 
plurality of electrical dropwires 96 which then exit the closure 4 via 
conduit 97 and are terminated on various ones of the electrical terminals 
44 illustrated in FIGS. 5 and 6. The significance of the electrical pin 
sets 93 is that they provide an easy, reliable, and convenient means of 
testing an electrical integrity of the card cage, cards, optical couplers, 
optical fibers, and other electronic components being housed within the 
card cage 51 at the time of its manufacture and prior to shipping for 
installation. Finally, FIG. 7 shows a preferred optional feature whereby 
posts 101 are provided in the base plate 48 for guiding the card cage into 
alignment with the base plate, the card cage bottom surface having mating 
post holes therein. Optionally, such post holes, not shown, are 
electrically connected to the backplane, and the posts 101 are 
electrically conductive and act as a ground for the card cage. 
Though the invention has been described by reference to certain preferred 
embodiments thereof, the invention is not to be so limited and is to be 
limited only by the appended claims.