Patent attributes
An operation knob that includes fin insertion holes formed at both side surfaces of the operation knob, a jig insertion hole formed at a side of the operation knob, and a separation portion formed by separating a part of the jig insertion hole. In the separation portion, a connection portion partially connects an upper facing side and a lower facing side of the connection portion and retains a predetermined clearance therebetween. The first separation surface of the connection portion on the upper facing side and the second separation surface of the connection portion on the lower facing side are contacted with each other, thus even if the connection portion is deformed so that the clearance becomes narrower, a minimum clearance corresponding to a height of the connection portion is retained based on the first separation surface and the second separation surface contacting each other.