Coupling/uncoupling device

A coupling/uncoupling device comprising:

• a columnar member configured by a divided pair of semicircular members;
• and
• a pair of coupling members comprised of first and second coupling members which form a circular holding section that is in contact with the columnar member along an outer circumferential surface of the columnar member and which hold the columnar member,
• wherein the circular holding section includes a circular inner surface section with which an outer circumferential surface of the columnar member is in slide contact, the circular inner surface section being formed from inner circumferential surfaces of a semicircular section in the first coupling member and a semicircular section in the second coupling member by disposing the semicircular section in the first coupling member and the semicircular section in the second coupling member to be opposed to each other so that the inner circumferential surfaces are continuous,
• the columnar member is configured to be rotatable along the circular inner surface section about a reference position where a contact surface of the pair of coupling members and a dividing surface of the columnar member are flush with each other,
• a first guide hole is provided with the first coupling member,
• a second guide hole is provided with the second coupling member,
• a first guide pin which is inserted into the second guide hole is provided with the first coupling member,
• a second guide pin which is inserted into the first guide hole is provided with the second coupling member,
• there is a first gap between the second guide hole and the first guide pin which is inserted into the second guide hole, the first gap permits the first guide pin to move, in the second guide hole, away from the contact surface in the radial direction of the first guide pin when the first guide pin moves with the first coupling member in an extending direction of the first guide pin, the first gap being formed between the first guide pin and the second guide hole with respect to the radial direction of the first guide pin,
• there is a second gap between the first guide hole and the second guide pin which is inserted into the first guide hole, the second gap permits the second guide pin to move, in the first guide hole, away from the contact surface in the radial direction of the second guide pin when the second guide pin moves with the second coupling member in an extending direction of the second guide pin, the second gap being formed between the second guide pin and the first guide hole with respect to the radial direction of the second guide pin,
• the coupling members are coupled when the columnar member rotates in a first rotating direction by a first predetermined angle from the reference position so that the contact surface and the dividing surface intersect with each other,
• a coupling state of the first and second coupling members is released when the columnar member rotates in a second rotating direction to the reference position, where the dividing surface is flush with the contact surface, the second rotating direction being opposite to the first rotating direction, and
• the second rotating direction is a direction in which the pair of semicircular members are permitted to radially and oppositely slide so that the first guide pin and the second guide pin are permitted to move away from the contact surface.