Note: Descriptions are shown in the official language in which they were submitted.
This invention reldtes to a protec~ion case for opkical
fiber splices, the case accommodat;ng a plurality of spliced pairs of
optical fibers, for telecommunications.
The protection case provides an interface between
"intra-office" fiber cables and individually buffered "patch-cord" ~ibers
which route to circuit packs. The case prov;des mounting or support
posit;ons for splices, attenuators if desired, and spare Fiber lengths
also if desired.
Broadly a protection case has an elongake box, access at one
end for incoming fiber cable or cables, egress for fibers, and a plurality
of packet members or assemblies hingedly atkached to the base of the box,
the packet members extending laterally across the box and pivsting about
axes transverse to the length of the box.
The invention will be readily understood by the following
description of an embodiment, by way of example, in conjunction with khe
accompanying drawings, in which:-
Figure 1 is a perspective view of a protection case, wi~h
the lid removed, and packet members illustrated in each of the two
possible positions;
Figure 2 is a top plan view of the base member, with cover
; removed, and some packet members in positlon;
Figure 3 is a cross-section on the line 3-3 of Figure 2;
Figure 4 is a plan view of a packet member ko a larger
scale,
Figure 5 is a edge view of a packet member in the base
member, similar to Figure 2, to a larger scale, illustrating khe optical
splices3 and attenuator, in position.
Figures 6 and 7 illustrate, to a larger scale, a packet
member with, respectively, a splice in position and an attenuator and two
splices in position.
As illustrated in Figure 1, the protection case comprises an
elongate base member 10, a cover 11, a trough-shaped inserk 12 and a
plurality of packet members 13.
Describing each member in more detail, with respect to
Figures 1, 2 and 3, the base member 10 has upturned sides 15 and one end
16 joined to the sides 15. At the other end o~ the base member, the base
is extended at 17 beyond the sides 15 and a web 18 extends across the base
member joining the ends of the sides, and defining, with an upturned end
19, a trough 20. Apertures 21 and 22 are formed in the web 18. Slots 23
are formed in the extension 17, the slots extending up into the end 19.
Within the base member 10 is the trough-shaped insert 12.
The insert has a ~lat base attached, as by spot welding, to the base o~
the base member 10, and has upturned sides 25. The sides 25 are spaced
from and extend parallel to the sides 15 to form ducts 26. The sides 25
are slotted at 27 to form comb-like structures along each side. Instead
of a single trough shaped insert, two spaced apart inserts can be
provided, to form the ducts 26.
Within the insert 12 are mounted a plurality o~ the packet
members or assemblies 13. As illustrated in more detail in Figures 4 and
5, each packet member is somewhat rectangular in plan form, having a flat
main web portion 29, with a top 30, and t~o sides 31 extending normal
thereto. The bottom is not straight but has two inclined sections 32
Joined by a short base section 33. The top 30 and sides 31 are turned
up and over for at least part of their lengths, as illustrated at 34~ to
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form channels, and also the short base sect;on 33 is turned up and over,
at 35 to form a further channel. Thus each packet member forms what is
effectively a shallow box. At the short base section 33 a cloth hinge 36
is provided by which a packet member is attached or connected ko khe base
of the insert 120 While the hinges are indicated in Figure 3, a hinge is
seen more clearly in Figure 5.
Positioned in each packet member is a holdlng member 40
conveniently of molded or extruded resilient material such as foam rubber.
Each member 40 has a number of transverse grooves 41 at each end. Over
the holding member 40 is a flexible retaining member 42 which snaps under
the turned over portions 34 and 35 on the top 30 and short base section
23. Th;s is seen in Figure 5.
As seen in Figure 2, a fiber cable 45 enters via trough 20
and through aperture 21. Strain relief is provided by a strain relief
bracket 46. Instead of a single optical fiber cable, up to four cables
can be connected, entering and exiting via trough 20 and apertures 21 and
22, incoming cables being gripped at the strain relief bracket 46. In
addition each cable can be individually gripped by strain relief members
attached to a flange 47 extending For part of the one side 15. The strain
members, not shown, are attached to the flange 47 by screws 48. This is
the ingoing side, for the "intra-office" cables.
At ~he other side of ~he case, optical fibers would emerge
into the right hand duct of Figure 2~ and individual strain members can be
attached to a flange 49 on the other side 15 by screws 50. The fibers
pass along the duct 2Ç, exiting via aperture 22 (Figure 1) into the trough
20. A further strain relief bracket can be prov~ded at 51 for outgoing
cables.
The cover 11 as seen in Figure 1, has a ton~ue 52 formed at
an end 53 which fits into a slot, not shown, in end 16 of the base member.
At the other end 54, the cover overlaps the top of the web 1~, ~hich is
higher than the sides 15 of the base member, and also has short corner
pieces 55. The cover is thus located at both ends, ~he sides of the cover
butting on to the sides 15 of the base member~ The cover does not extend
over the trough 20 in the example illustratedO The cover is retained at
end 54 by screws passing through holes 56 into nuts or similar members
attached to the bottom of the base member.
Figures 6 and 7 illustrate the alternate arrangements of a
splice positioned in a packet mem~er and an attenuator with related
splices positioned in a packet member. Normally a packet member holds one
splice, such as when a pair of fibers, one from each cable, is spliced.
Such is seen in Figure 6, the splice indicated at 50, or an attenuator
which is connected to the pair oF fibers, one from each cable, by two
splices. In Figure 7, the attenuator is indicated at 51 and the two
splies at 52. The fibers are coiled round in the packet, as indicated at
53. The fibers enter from a duct 26 and pass under the turned over
portion 35. Similarly fibers exit from under the turned over portion 35
to a duct 26. In both instances the fibers also pass through one of the
slots 27. By so arranging for the fibers to pass under the turned over
portion, both on initial entry and prior to exit, the fibers rotate as a
packet member is pivotted up or down, rather than bend. This avoids
possible damage or breakage. There will be extra fiber before and after a
splice, as in Figure 6, and extra fiber before one splice, after the other
splice and between each splice and the attenuator, as in Figure 7. It may
be necessary to vary the diameter of the coil of fiber, and fiber can be
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positioned in any spare groove ~1 to make adjustment for the length of
fiber to be accommodated.
In the particular example, sixkeen packet members or
assemblies are provided and the protection case is dimensioned for
installation on standard equipment racks. The protection case has a low
profile and can be mounted on the back of equipment racks which have no
available rack space. Again, in the example, the packet members are
approximately three inches by 3 3/4 inches, but these dimensions can vary,
as can the number of splices and/or attenuators carried by each packet
member. Conveniently the splices and attenuators are a push fit into the
grooves 41j being retained by the resilience of the material of the member
40, and the strap ~2. However other ways of mounting the splices and
attenuators can be used.
The invention provides a compact assembly having a low
profile and yet which allows ready access to a particular splice and/or
attenuator by simply flipping up the packet members prior to that packet
member to which access is required. In the packaged or stored position
the packet members lie at an angle of about 30 to the horizontal, and
when flipped up move to approximately 15 beyond the vertical. This can
be achieved by a self-limiting effect o~ the hinges or by a suitable stop
at the end remote from the entry and exit trough 17. For initial location
of the packet members small holes or other locating marks 60 can be
provided in the brse of the insert 12.
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