To freely extend the illumination length by producing an optical transmission cable from a bendable outer coating skin and a core material, which is a soft and transparent resin core and with which the inside of the coating skin is filled, enabling the optical transmission cable to emit light rays from the side face, and installing a freely rotatable joint mechanism between a light source and the base end part of the optical transmission cable.
A rotation holder 31 is attached to the outside of the base end part 3A of an optical transmission cable 3 and the winding holder 31 is held in a freely rotatable manner through a bearing 42A on the rotation center axis of the winding drum 2. The winding holder 31 is set on the opposite to the tip end face of an optical guide part 15 fixed in a joint 16 at an extremely narrow distance to compose a joint mechanism. Moreover, an illumination part 32 is installed in the tip end part 3A of the optical transmission cable 3. Moreover, the optical transmission cable 3 is so composed as to emit light out of not only the tip end part but also the outer circumferential face of the side in the whole length.
TERAHAMA TATSUO
SUGIYAMA HIDEO
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