Tubular-member lock mechanism

A tubular-member lock mechanism, comprising:

• a tubular member having an engagement portion formed on an outer periphery of the tubular member;
• a cylindrical housing of which the tubular member is engaged at at least one end;
• and
• a lock member through which the housing and the tubular member are locked to or released from each other,
• wherein the housing includes a lock-member guide wall turnably guiding the lock member, at least two sliding surfaces symmetrically arranged at two sides of the housing, each of the at least two sliding surfaces including a first surface and a second surface facing the first surface, the first surface and the second surface having different inclinations, and a slit through which one portion of the lock member passes to engage the engagement portion of the tubular member mounted to the housing;
• and
• when the one portion of the lock member engages the engagement portion of the tubular member, the tubular member is locked to the housing by an elastic force of the lock member, and
• when the lock member is rotated on the lock-member guide wall of the housing by a rotational load, one tip portion of the lock member slides on the first surface of one of the at least two sliding surfaces, and another tip portion of the lock member slides on the second surface of another of the at least two sliding surface to spread the lock member to be released from the engagement portion of the tubular member, and the tubular member is released from the housing.