1. Technical Field
This invention relates to an optical fiber cable; and more particularly relates to an optical fiber cable having a buffer tube.
2. Description of Prior Art
Optical fiber cables having flexible strength members are known in the art. Siecor makes a cable having contra-helically wound flexible strength members arranged between, but not coupling, a buffer tube and an outer protective jacket. In order to meet cold temperature requirements, Siecor's cable requires a pressure extruded jacket and a contra-helically winding, which complicates and increases the cost of the cable manufacturing process, because (1) expensive spinners are needed (2) the line speed is limited due to the maximum spinner RPMs and (3) the process must be stopped for yarn changes.
Other cables are known in the prior art. U.S. Pat. No. 4,892,382 teaches a cable having inner fiber yarn material and polyurethane fiber glass arranged between an inner buffer tube and an outer protective tube. U.S. Pat. No. 5,561,729 shows and describes a cable having tensile strength aramid yarn, water absorbent material, tape and antibuckling members arranged between an inner buffer tube and an outer protective jacket. U.S. Pat. No. 4,892,382 shows and describes a cable having tensile strength members, water absorbent material, tape, and impregnated yarn antibuckling members arranged between an inner buffer tube and an outer protective jacket. These composite cables suffer from one or more problems such as not providing easy access to the optical fibers, or not meeting the cold temperature requirement.
However, a technical problem remains unsolved in the prior art, i.e. to couple an outer protective jacket and an inner tube to meet cold temperature requirements in the cable industry, i.e. to minimize cable shrinkage at -40 degrees Celsius that causes undesirable signal attenuation in the optical fiber, while enabling manual separation to gain service access to the optical fibers inside the inner buffer tube.
USPTO Backgrounds
USPTO Backgrounds