Also, an inserting path for the axis protrusion continuing to the receiving portion is adapted to expand in {HEAD ~ the direction} perpendicular to {TAIL ~ the rotation axis} by an elastic deformation when the inserting path receives the axis protrusion 
perpendicular to
Also , an inserting path for the axis protrusion continuing to the receiving portion is adapted to expand in { HEAD ~ the direction } perpendicular to { TAIL ~ the rotation axis } by an elastic deformation when the inserting path receives the axis protrusion
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH