OSCILLATION COUPLER

A swingable connecting device is provided having a supporting body to be attached to a large-diameter threaded bore formed in a target object without changing the size of the shackle or the supporting body. The swingable connecting device includes an oscillation supporting mechanism for swingably supporting a shackle 5 to a supporting body 19. A mounting bolt 11 of the supporting body 19 is a double-ended bolt having a first male threaded portion 1 and a second male threaded portion 2 formed separately at opposite ends thereof and having different diameters from each other. A bolt shaft portion 3 whose diameter varies continuously from the first male threaded portion 1 to the second male threaded portion 2 is formed between the first male threaded portion 1 and the second male threaded portion 2. The supporting body 19 is provided with a bolt hole 10 for allowing the bolt shaft portion 3 to fit into and engage with the bolt bore, through which the small-diameter second male threaded portion 2 extends. The bolt bore 10 has an inner surface profile, in which an inner diameter thereof continuously varies with an outer circumferential surface of the bolt shaft portion 3. A nut 6 is screwed to the second male threaded portion 2 extending through the bolt bore 10, thereby to connect the mounting bolt 11 integrally with the supporting body 19 to retain the mounting bolt 11 in the supporting body 19.