Abstract

ISSUE: A chain tensioning device with a short center distance that can impart a tensioning force to a plurality of chain spans at the same time with a simple structure. MEANS OF RESOLUTION: A tensioning device (1) includes a first tensioner arm (2) having an arm part (20) disposed outside a chain span (C)1 and a flange part (21) integrated with the arm part (20) and projecting toward the internal space between chain spans (C1, C2), a second tensioner arm (3) having an arm part (30) disposed outside a chain span (C2) and a flange part (31) integrated with the arm part (30), projecting toward the internal space between chain spans (C1, C2), and overlapping the flange part (21), a linking part pivotably linking the flange parts 821, 31) at the overlapping portion of the flange parts (21, 31), and a tensioner (4) urging the first tensioner arm (2) toward the chain span (C1).