Coupling member, fluid-device connecting jig, and fluid-device connecting structure

A coupling member to be used for a fluid-device connecting structure comprising:

• a first fluid device having a first connection part;
• a second fluid device having a second connection part;
• an annular seal member placed between the first connection part and the second connection part;
• and
• the coupling member for coupling the first connection part and the second connection part through the annular seal member, wherein:
• the coupling member includes a single-piece first coupling segment and a single-piece second coupling segment, each having a rotational joint part at a first end,
• the first connection part and the second connection part each have a cylindrical outer shape,
• the first coupling segment and the second coupling segment each having a protruding portion engageable with the first connection part and the second connection part respectively,
• the first coupling segment has a U-like shape having an opening and is engageable with the second coupling segment at points spaced more than 180 degrees of an entire circumference of each of the first connection part and the second connection part,
• the opening has a dimension smaller than a diameter of a tubular part of each of the first connection part and the second connection part, and
• the first coupling segment is provided with a thin wall portion that is opposite the opening and that is radially thinner than other adjacent portions of the first coupling segment so as to be configured to diametrically expand the first coupling segment outward by a distance corresponding to a difference between the dimension of the opening and the diameter of the tubular part of each of the first connection part and the second connection part.