SHAFT CENTER POSITION IDENTIFICATION JIG FOR PIPE, AND PIPE SHAFT CENTER POSITION IDENTIFICATION METHOD AND ATTACHMENT HOLE RULING METHOD USING THE SHAFT CENTER POSITION IDENTIFICATION JIG

摘要

PROBLEM TO BE SOLVED: To easily and surely identify the shaft center of a pipe such as an existing pipe. SOLUTION: The jig includes a center shaft 2 having a male thread 21a; a nut member 3 screwed to the male thread 21a of the center shaft 2; a bearing member 4 rotatably supported by the center shaft 2; four front arms 5 the base ends of which are rotatably connected to the nut member 3 at circumferential intervals; four rear arms 6 the base ends of which are rotatably connected to the bearing member 4 at circumferential intervals; and four receiving members 7 to each of which the top ends of each corresponding front arm 5 and each corresponding rear arm 6 are rotatably connected. Each front arm 5 and each rear arm 6 are formed in the same length. Each receiving member 7 has a receiving surface 71 parallel to the shaft center of the center shaft. The center shaft 2 is rotated to rotate each corresponding front arm 5 and each corresponding rear arm 6 respectively at the same angle relative to the center shaft 2, and each receiving member 7 is allowed to abut on the inner periphery of an existing pipe S to dispose the center shaft 2 on the shaft center of the pipe. COPYRIGHT: (C)2011,JPO&INPIT