Installation device and installation method for piston ring

An installation device for a piston ring, comprising:

• an extruding mechanism that horizontally extrudes a piston ring occupying a lowest position among piston rings held and stacked up and then positions the extruded piston ring at a predetermined position, the extruding mechanism being driven downwardly in a vertical direction by a predetermined amount after extruding the piston ring and then driven to return to a waiting position;
• a ring holding mechanism that has a guide passage used to guide the piston ring extruded by the extruding mechanism while holding the piston ring in such a way as to sandwich the piston ring from upward and downward directions, the ring holding mechanism being driven so as to move close to and apart from a piston in one direction intersecting with an extruding direction, and being capable of defining an insertion hole into which the piston is inserted in a center area thereof;
• a ring diameter extending mechanism that extends a diameter of the piston ring held by the ring holding mechanism while being in contact with an inner surface of the piston ring, the ring diameter extending mechanism being driven to freely enter and leave the guide passage defined by the ring holding mechanism, and being driven to recede toward a position defining a part of the guide passage when an extended state of the piston ring is released;
• and
• a piston holding member that holds the piston inserted into the insertion hole at a predetermined position.