| CPC A63B 53/0437 (2020.08) [A63B 53/0466 (2013.01)] | 20 Claims |
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1. A hollow golf club head comprising:
a face portion that forms a striking face;
a crown portion that forms a crown outer surface and a crown inner surface;
a sole portion that forms a sole outer surface and a sole inner surface; and
a hosel portion, wherein
the crown portion includes a crown atypically-shaped portion and a crown rib that is disposed on the crown inner surface,
the crown atypically-shaped portion is a hollow crown projection that forms a projection on the crown outer surface while forming a recess on the crown inner surface,
in a planar view of the golf club head, the crown rib is disposed on a crown center side relative to a center of the crown atypically-shaped portion,
the crown center side refers to a position closer to a crown center,
the center of the crown atypically-shaped portion refers to a geometric center of a closed figure indicated by a contour line of the crown atypically-shaped portion that defines an overall shape of the crown atypically-shaped portion in the planar view,
the crown center refers to a point obtained by moving a geometric center of a closed figure, indicated by an outer contour line of the golf club head that defines an overall shape of the golf club head toward a back side by half of a distance Da in the planar view,
when a frontmost point of the golf club head in a longitudinal cross section that passes through the geometric center of the golf club head is denoted by T1, and an uppermost point of the striking face in the longitudinal cross section is denoted by T2, then the distance Da is a distance between the frontmost point T1 and the uppermost point T2 in the planar view,
in the planar view, the crown rib is disposed between the closed figure indicated by the contour line of the crown atypically-shaped portion and the crown center,
on the crown outer surface, the hollow crown projection protrudes from a crown base surface that forms a convex curved surface, the contour line of the crown atypically-shaped portion is a boundary line between the crown base surface and the crown atypically-shaped portion, and
in a cross section of the crown outer surface, the contour line of the crown atypically-shaped portion is indicated by an inflection point or a vertex of an angular corner.
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