To quickly bring a ring into a perimeter measurable condition.
In this perimeter measuring instrument 1, the metal ring W conveyed horizontal-directionally is laid on the first roller 2 and second roller 3, while kept under a horizontal direction, to measure a perimeter of the metal ring W. The metal ring W is pulled in into an inside of a ring holding means 4 having a space narrower than a diameter of the metal ring W and held horizontally to be deformed into a substantial elliptic shape. The ring holding means 4 is moved from the condition by a lifter 5 to be moved to a position where the metal ring W includes ring attaching faces 2a, 3a of the first and second rollers 2, 3. The second roller 3 is moved along a direction separated from the first roller 2 under the condition, and the metal ring W is attached thereby to the first roller 2 and second roller 3 to measure the perimeter of the metal ring W. After the measurement, the second roller 3 is approached to the first roller 2, and the metal ring W is held by the ring holding means 4 to be moved upwards by the lifter 5.
SUGISONO TETSUO
TAHIRA HIROKI
SAITO KOJI
INAGI KATSUSHI
Takehiro Chiba
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