A coupling method for coupling a coupling subject member using a coupling device comprising:
- a detachable member that can be attached to and detached from a first coupling subject member;
- a first coupling member provided on the detachable member;
- a second coupling member provided on the detachable member;
- a connecting member provided on the detachable member so as to connect the first coupling member to the second coupling member;
- and
- a third coupling member connected to the detachable member and coupled to a second coupling subject member,
- wherein the first coupling member and the second coupling member each include:
- an elongated hole;
- a contact portion provided on an outer peripheral lower portion of the first coupling member and the second coupling member such that one end portion is positioned on an upper side of another end portion;
- and
- a hook-shaped portion provided on the one end portion of the contact portion so as to be connectable to the first coupling subject member,
- the connecting member includes a fixing shaft that extends in a horizontal direction and is inserted into respective elongated holes in the first coupling member and the second coupling member, and
- the first coupling member and the second coupling member are supported so as to be capable of rotating about the fixing shaft and moving relative to the fixing shaft,
- the coupling method comprising:
- a step in which, when the detachable member moves toward the lower side while the first coupling member and the second coupling member are not coupled to the first coupling subject member, respective contact portions of the first coupling member and the second coupling member are pressed by the first coupling subject member, whereby the first coupling member and the second coupling member rotate about the fixing shaft such that the one end portion of each of the contact portions moves toward the upper side, and move relative to the fixing shaft in a direction for reducing a distance from the contact portion of the first coupling member to the contact portion of the second coupling member;
- a step in which, when the detachable member then moves further toward a lower side such that the first coupling subject member separates from the respective contact portions of the first coupling member and the second coupling member, the first coupling member and the second coupling member move relative to the fixing shaft in a direction for increasing the distance from the contact portion of the first coupling member to the contact portion of the second coupling member;
- and
- a step in which, when the detachable member then moves toward the upper side, respective hook-shaped portions of the first coupling member and the second coupling member are connected to the first coupling subject member such that the detachable member is coupled to the first coupling subject member.