Optical waveguides – Optical transmission cable – Tightly confined
Reexamination Certificate
1999-02-19
2001-03-20
Bovernick, Rodney (Department: 2874)
Optical waveguides
Optical transmission cable
Tightly confined
C385S102000, C385S103000, C385S104000
Reexamination Certificate
active
06205277
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to optical fiber cables used for indoor and/or outdoor premises applications and, in particular, to optical fiber cables which do not incorporate greases and/or gels within the cables for water-blocking.
2. Description of the Related Art
In the wiring of premises, such as apartment and commercial buildings, with fiber optic cables, it is common to use a cabling system in which many cables enter the premises and individual cables are broken out for use in individual stations within the building. Heretofore, it has been known to use a high density breakout cable system for wiring such premises. Typically, the fiber optic cables of such a cable system (known as “breakout cables”) are available in spools which can be pulled through the building in a routine manner.
Typically, the prior art breakout cables are constructed with water-blocking properties such as by incorporating greases and/or gels between an outer jacket and internally carried fibers of the cables. The greases and/or gels are intended to prevent water from migrating through and about the fibers of the cable if the outer jacket of the cable becomes breached in some manner. Although meeting with a certain degree of success, cables incorporating the prior art greases and gels can be difficult to work with due to the messiness and handling difficulties thereof For example, the greases and/or gels can tend to leak from the cable, such as during a cable termination process. Additionally, the greases and/or gels are particularly undesirable when exposed to warm temperatures because the warmed greases and/or gels tend to flow more readily within the cable jacket and can tend to drip out of the cable, such as at a cable termination point, thereby potentially soiling or damaging components, i.e. electrical components, found within a cable termination cabinet as well as diminishing the water blocking properties of the cable.
Therefore, there is a need to provide improved fiber optic cables which address these and other shortcomings of the prior art.
BRIEF SUMMARY OF THE INVENTION
Certain objects, advantages and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The present invention generally is directed to dry core optical fiber cables which do not incorporate greases and/or gels for water-blocking. In a preferred embodiment, the cable incorporates a plurality of sub-units with each of said sub-units being arranged adjacent another of the sub-units so that the plurality of sub-units define an outer periphery. Preferably, each of the sub-units includes a plurality of optical fibers, a yarn layer and a sub-unit jacket, with each of the optical fibers being arranged adjacent another of the optical fibers. The sub-unit jacket surrounds the optical fibers, with the yarn layer being disposed between the optical fibers and the sub-unit jacket. An outer jacket surrounds the plurality of sub-units, with water-blocking tape being disposed between the outer jacket and the outer periphery of the sub-units.
In accordance with another aspect of the present invention, an alternative embodiment of the cable incorporates an elongated organizer which possesses a first breaking strength. At least one water-blocking yarn member is arranged about the organizer and a plurality of sub-units are arranged in reverse-oscillated lay about the organizer so that the water-blocking yarn member is disposed between the organizer and the plurality of sub-units. Preferably, each of said sub-units include a plurality of optical fibers, an aramid yarn layer and a sub-unit jacket. Each of the optical fibers possess a second breaking strength, with the first breaking strength being greater than the second breaking strength.
A method aspect of the present invention comprises the steps of: providing at least one water-blocking yarn; wrapping a plurality of sub-units about the water-blocking yarn in a reverse-oscillated lay; wrapping the plurality of sub-units with water-blocking tape; and, forming an outer jacket about the plurality of sub-units and the water-blocking tape so that the water-blocking tape is disposed between the plurality of sub-units and the outer jacket.
The numerous features and advantages of the present invention will be more readily apparent from the following detailed description read in conjunction with the accompanying drawings.
REFERENCES:
patent: 5249248 (1993-09-01), Arroyo et al.
patent: 5268983 (1993-12-01), Tatarka et al.
patent: 5389442 (1995-02-01), Arroyo et al.
patent: 5751879 (1998-05-01), Graham et al.
Mathis Terry D.
Newton Wayne M.
Sheu Jim J.
Shmukler Mark I.
Viriyayuthakorn Montri
Bovernick Rodney
Lucent Technologies - Inc.
Pak Sung
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