Optical waveguides – Optical transmission cable – With electrical conductor in the same cable
Reexamination Certificate
2000-01-28
2002-07-02
Ullah, Akm E. (Department: 2874)
Optical waveguides
Optical transmission cable
With electrical conductor in the same cable
C385S102000, C385S105000
Reexamination Certificate
active
06415084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a complex cable adapted for being wired under office floors, building floors or the like. The complex cable of the invention is an improved version of the data-transmission cables known in the prior art and used in under-floor wiring.
2. Description of Background Information
Recently, offices have become the main target for applying automation technologies, the so-called “office automation” technologies. In offices, the floors have to be designed so as to provide wiring spaces. The base floors of offices are often covered with panels of a given thickness and tile carpets. These panels and tile carpets are arranged side-by-side and head-to-tail, and form a “double-floor structure”. The system of this construction is often called a “free access floor system”.
The panel described above may be a floor panel
1
having a square shape (viewed from the top) with a given thickness, as shown in FIG.
1
. This floor panel
1
may be defined by crossing channel portions
4
so as to form, for example, four unitary panel portions
2
having a substantially square shape and integrally bonded to each other via link portions
3
. Each of the channel portions
4
has a substantially U-shaped cross-section and a given width, and runs between two unitary panel portions
2
. The channel portions
4
can thus serve as wiring paths.
Further, the upper longitudinal side of the channel portions
4
, corresponding to the upper side lines of unitary panel portions
2
, are provided with steps
5
. The channel portions
4
may then be covered with rectangular trench covers
6
or cross-like trench covers
7
by using the steps
5
as rests, so that the top openings of channel portions
4
can be closed.
A floor panel
1
thus formed defines a square (viewed from the top) and the flat floor surface comprises a plurality of unitary panel portions
2
and a plurality of trench covers
6
and
7
. A plurality of floor panels
1
are assembled in turn side-by-side and head-to-tail, so that the channel portions
4
extend continuously in crossed directions and form extended channel portions
8
. Various kinds of cables may be wired through the channel portions
8
. The cables include communications cable units
9
respectively incorporating a plurality of communications cables for data transmission, fiber-optic cables
10
(FIG.
3
), electric source cables or the like.
FIG. 2
shows a type of communications cable unit
9
containing a plurality of data transmission cables, e.g. twin-type data transmission cables
17
. Such twin-type data transmission cables
17
are manufactured as follows. There is first provided an electrical wire
13
consisting of a conductive element
11
such as copper, and secondly an insulating coating
12
made of polyethylene (PE) or the like surrounding the conductive element
11
. A pair of electrical wires
13
prepared in this way is twisted to form a twin-wire strand
14
. Four pairs of twin-wire strands
14
are then wrapped with a plastic tape
15
made of polyethylene terephthalate (PET) or PE. The wrapped twin-wire strands
14
are subsequently coated with a sheath
16
made of poly (vinylchloride), i.e., PVC, or the like.
The communications cable unit
9
also comprises an interposition member
18
extending along its axial center line. The interposition member
18
is then surrounded by six groups of such twin-type data transmission cables
17
in substantially parallel relation to one another over the length of the member. Subsequently, the-interposition member
18
and the twin-type data transmission cables
17
are packed with a plastic tape
19
to yield a communications cable unit
9
having an outer diameter of around 15 mm.
The communications cable units
9
described above are often used for short distance communications, e.g., on a one-conductor one-circuit basis. The system is particularly suited for the communications in a same office or building.
By comparison,
FIG. 3
shows a known fiber-optic cable
10
which contains inter alia a pair of fiber-optic cords
24
. To prepare a fiber-optic cord
24
, optical fibers are first covered with a nylon or UV-hardened resin layer, to form a fiber-optic wire
21
. The fiber-optic cord
24
comprises a fiber-optic wire
21
thus prepared, a buffer material layer
22
made of aramide fibers, surrounding the fiber-optic wire
21
, and a coating made of PVC, surrounding the buffer material layer
22
. In addition to the fiber-optic cords
24
, the fiber-optic cable
10
contains a tension member
26
extending along its axial center line, as well as a pair of interposition members
25
made of PP yarns or PVC threads. In this construction, the tension member
26
is surrounded by the pair of fiber-optic cords
24
and the pair of interposition members
25
in substantially parallel relation to one another over the length of the member, which are then wrapped with a taping cloth
27
. The outer circular surface of taping cloth
27
is further covered with a sheath
28
made of PVC or the like, to give an outer diameter of about 10 mm.
The fiber-optic cables
10
are commonly used for long distance communications, for example, on a one-fiber multiple-transmission basis. The system is particularly suitable for the communications between companies, or between head office and its branch offices. Thereafter, the communications cable units
9
and the fiber-optic cables
10
are wired independently through different process steps. This known wiring process therefore requires many process steps and increases installation costs.
Furthermore, to wire them as separate cables, a larger space is required. However, some office floors may not be able to ensure enough space for such a wiring process.
If such is the case, an optical cable
10
may be forcibly wired in a wire path having insufficient space, and the optical cable
10
thus receives a lateral stress. This lateral stress usually causes a transmission loss.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide a complex communications cable for under-floor wiring which incorporates data transmission cables and fiber-optic cables. By virtue of this construction, offices may be easily wired, even if the office floors provide little space. This advantage may reduce installation costs.
To this end, there is provided a complex cable for under-floor wiring incorporating at least one fiber-optic cable and a plurality of communications cables for data transmission. The fiber-optic cable includes at least one fiber-optic wire and a first tightening member assembling the at least one fiber-optic wire. The plurality of communications cables for data transmission respectively include at least one twin-wire strand and a second tightening member assembling the at least one twin-wire strand. The at least one fiber-optic cable is surrounded by the plurality of communications cables for data transmission in substantially parallel relation to one another over the length of the fiber-optic cable. The fiber-optic cable and the plurality of communications cables for data transmission are then assembled by a third tightening member.
Preferably, the at least one fiber-optic cable includes at least one interposition member provided in a substantially parallel relation over the length of the at least one fiber-optic wire, and the at least one fiber-optic wire and the at least one interposition member are assembled by the first tightening member.
The above-mentioned first, second and third tightening members may respectively include a plastic tape.
Typically, the at least one fiber-optic wire includes one optical fiber as a core optical element, but it may also include a plurality of optical fibers.
Additionally, the fiber-optic cable may be provided along a central axis of the complex cable, and the plurality of communication cables may be arranged therearound. The complex cable may also be configured such that each communication cable abuts an adjacent communication cable and the fib
Connelly-Cushwa Michelle R.
Sumitomo Wiring Systems Ltd.
Ullah Akm E.
LandOfFree
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