PURPOSE: To improve respective characteristics such as side-pressure-resistant characteristic, bending characteristic, or twisting characteristic by providing, on the side face of PE sheath, a spiral groove whose twisting direction is the same as that of an iron wire armor and in which the relationship between a pitch and a pitch diameter is specified.
CONSTITUTION: A spiral groove 23 is provided in the plastic sheath 22 of a power cable 12 in such a way that an optical fiber unit 24 is housed therein. The unit 24 is not fixed by a presser winding 25 so that it moves inside the groove so as to can cel a tensile and a compressive stresses arising in and outside of a neutral plane upon bending. The swirl direction of the groove 23 is designed to be the same as the twist direction of an iron wire armor 34, and the relational equation such as n/m=D/d is designed to be satisfied when the ratio between a twist pitch 'P' and the pitch diameter 'D' of the armor 34 is designated to be 'n' and the ratio between a spiral pitch 'p' and a pitch diameter 'd' of the groove 23 is designated to be 'm'. When a composite cable 10 is twisted, the length of the groove 23 is substantially kept constant, thus no stress is applied to the unit 24 so that a lowering of life and a degradation of transmission loss can be prevented.
| JP2003270502 | OPTICAL FIBER CABLE DRAW ANCHORING JIG |
| JP2003243845 | OPTICAL INFORMATION COMMUNICATING UNIT |
| JPH06297546 | MANUFACTURE OF OPTICAL FIBER COMPRESSION FEEDING PIPE |
SAWANO HIROYUKI
MOGI AKIO
MIYAMOTO SUEHIRO
SUZUKI HIDEO
| JPS6283451A | 1987-04-16 | |||
| JPS63274014A | 1988-11-11 |