Optical waveguides – Optical transmission cable – Tightly confined
Reexamination Certificate
1999-03-25
2001-05-22
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
Optical transmission cable
Tightly confined
C385S103000, C385S106000, C385S100000
Reexamination Certificate
active
06236790
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical-fiber cable having a cylinder body disposed at the center, with optical-fibers being accommodated in the cylinder body, and relates, more particularly, to an optical-fiber cable which can be manufactured easily at low cost by forming a belt-shaped material into a cylinder shape to form a cylinder body.
2. Description of Related Art
There have been known 1) a slot type cable, 2) a loose tube type cable and 3) a center tube type cable, for example, as structures of an optical-fiber cable for assembling several tens to several hundreds of optical-fibers together.
According to the slot type cable, optical-fiber ribbons are accommodated within grooves that is formed on the outer peripheral surface of a rod, and a pressed-wound layer and a sheath are formed sequentially on the periphery of the slotted rod. A tension member is disposed at the center of the slotted rod, with a rip cord disposed between the pressed-wound layer and the sheath.
According to the loose tube type cable, loose tubes accommodating optical fibers are stranded around central tension members, and a pressed-wound layer and a sheath are formed sequentially on this assembly. Jelly is filled within the loose tubes, and rip cords are distributed between the pressed-wound layer and the sheath.
According to the center tube type cable, there is disposed, at the center, a center tube accommodating optical-fiber ribbons therein, and a sheath is formed on the periphery. Tension members are embedded within the sheath, and jelly is filled within the center tube. Further, rip cords are disposed between the center tube and the sheath.
These optical-fiber cables have had the following problems.
The slot type cable has a suitable structure for obtaining a multiple-core optical-fiber cable as the optical-fibers are accommodated in the spiral grooves formed on the outer periphery of the rod. However, the slot type cable has a problem that its structure becomes costly in the case of a small-core optical-fiber cable due to high cost of the slotted rod.
The loose tube type cable has a suitable structure for obtaining a small-core optical-fiber cable by using single-core optical-fibers. However, the loose type cable has a problem of having a larger number of manufacturing processes because this structure requires a process of forming loose tubes and a process of assembling a plurality of loose tubes around a central tension member. Further, in the case of structuring a multiple-core optical-fiber cable by using optical-fiber ribbons, this has a problem that an external diameter becomes larger. Furthermore, as the loose tubes are manufactured by a method of forming a tube by extruding a resin while inserting optical-fibers at the same time, it has been unavoidable to charge jelly into the whole inside of the loose tubes in order to prevent a molten resin from adhering to the optical-fibers at the time of forming by extrusion. Accordingly, this has an inconvenience of incurring the cost of charging the jelly.
The center tube type cable can be manufactured in a relatively small number of processes because of its simple structure. However, the center tube is formed by extrusion while inserting optical-fibers and optical-fiber ribbons at the same time, as in the case of the loose tube type cable. Therefore, it has been unavoidable to charge jelly into the tubes in order to prevent a move of the optical-fiber ribbons in a longitudinal direction within the center tube. This has a problem of high manufacturing cost.
Moreover, both the loose tube type cable and the center tube type cable have had a problem that the tube has to be disconnected at the time of carrying out a connection such as a branch connection or the like.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical-fiber cable capable of being manufactured at lower cost than by the conventional method, and to provide a method of manufacturing this optical-fiber.
It is another object of the present invention to provide an optical-fiber cable that facilitates a connection such as a branch connection, and to provide a method of manufacturing this optical-fiber cable.
According to a first aspect of the present invention, there is provided an optical-fiber cable which comprises an optical-fiber; and a cylinder body which is made from a cylindrically formed belt-shaped material and made of resin and which accommodates the optical-fiber therein.
The optical-fiber includes a fiber ribbon type which has plural fibers and a single-fiber type.
Preferably, the optical-fiber cable further comprises a first tension member which is disposed at an outside of the cylinder body; and a sheath which covers the outside of the cylinder body and the tension member.
Preferably, the optical-fiber cable further comprises: a filler which is disposed with a distance along the optical-fiber in a longitudinal direction thereof and which is provided between the optical-fiber and the cylinder body for preventing a move of the optical-fiber in a longitudinal direction.
Preferably, the belt-shaped material has a first end and a second end, and an adhesive member is adhered to the first end and the second of the cylindrically-formed belt-shaped material.
Preferably, the adhesive member has a tension member therein.
Preferably, the optical-fiber cable further comprises: a first rip cord which is disposed at the outside of the cylinder body within the sheath.
Preferably, the optical-fiber cable further comprises: a second rip cord; and a second tension member. The first rip cord and the second rip cord are symmetric with respect to the optical-fiber. The first tension member and the second tension member are symmetric with respect to the optical-fiber. A first plane which includes the first rip cord and the second rip cord and a second plane which includes the tension first member and the second tension member cross each other.
Preferably, the rip cord has one of a high-tensile high-polymer fiber, a glass fiber, a cotton yarn and a metal wire.
According to a second aspect of the present invention, there is provided a method of manufacturing an optical-fiber cable, comprising the steps of: accommodating a optical-fiber in a cylinder body while forming a belt-shaped material into the cylinder body; disposing a tension member at an outside of the cylinder body; and covering the outside of the cylinder body and the tension member with a sheath.
Preferably, before forming the belt-shaped material into the cylinder body, the belt-shaped material is disposed along the optical-fiber, and a filler is applied with a distance along to one of the belt-shaped material and the optical-fiber in a longitudinal direction.
Preferably, an adhesive member is adhered to a first end and a second end of the cylindrically formed belt-shaped material.
REFERENCES:
patent: 5131064 (1992-07-01), Arroyo et al.
patent: 5509097 (1996-04-01), Tondi-Resta et al.
Iwata Hideyuki
Miyamoto Matsuhiro
Okada Naoki
Sato Yoshiyasu
Watanabe Hirohito
Fujikura Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Palmer Phan T. H.
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