Nkk Corporation

Takashi Tsukui

Yasunori Yoshie

An apparatus for manufacturing a metal tube covered optical fiber cable, having an assembly (2) consisting of a plurality of roller pairs for forming a metal strip (1) subjected to traction and causing both side edges of the metal strip to abut against each other to form a metal tube, a laser welding device (7) for radiating a laser beam on abutment portions of the metal tube to bond the abutment portions, thereby obtaining a sealed metal tube (1c), and an optical fiber guide means (6) for guiding an optical fiber (5) into the formed metal tube (1a), wherein the laser welding device (7) determines a focal point shift amount so that a rear bead width determined by an outer diameter and a wall thickness of the metal tube falls within a predetermined range, and laser welding is performed at a welding rate corresponding to the determined focal point shift amount.

Apparatus for manufacturing metal tube covered optical fiber cable and

An apparatus for manufacturing a metal tube covered optical fiber cable, including an assembly (2) having a plurality of roller pairs, for causing both side edges of a metal strip (1) to abut against each other to form the metal strip into a metal tube, a laser welding device (7) for radiating a laser beam to abutment portions of the metal tube to bond the abutment portions to obtain a sealed metal tube (1c), and an optical fiber guiding element (6) for guiding an optical fiber (5) in a formed metal tube (1a) comprises an extra length control system comprising a tension adjusting element (15) for the metal strip (1) arranged in the upstream of the assembly (2) and a tension adjusting element (14) for the optical fiber (5) arranged in the upstream of the optical fiber guide element (6), and a traction element (11, 13) including tension variable element (11) for the metal tube covered optical fiber cable (1d).

An apparatus for manufacturing a metal tube covered optical fiber cable comprises an assembly of a plurality of roller pairs for forming a metal strip into a metal tube so that both side edge portions abut against each other, a laser (7) for welding the abutment portions with a laser beam to obtain a sealed metal tube (1c), an optical fiber guide for guiding an optical fiber (5) into the formed metal tube (1a), and a traction apparatus including a tension variable element for continuously drawing a sealed metal tube (id). The optical fiber guide is elastically urged against an inner wall opposite to an irradiated surface of the metal tube so that the optical fiber is protected even when the focal point of the laser beam is positioned below the abutment portions of the metal tube. In one embodiment a leaf spring mechanism is used to elastically urge the optical fiber guide.

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Tokyo, Japan

Takashi Tsukui