US Patent 7318609 Chuck and tube joint

A chuck includes an annular ring portion, a first engaging portion which extends along a central axis of the annular ring portion and which engages with the first tube joint member, and a second engaging portion which extends from the annular ring portion along the central axis of the annular ring portion and which elastically engages with a second tube joint member. A-three-dimensionally shaped portion, which is an end of the second engaging portion, includes a pair of expanded portions on a metal plate. The annular ring portion is formed by rounding the metal plate with both ends, which are not fixed to one another so that both ends are displaceable circumferentially.