| 摘要 |
<p>PURPOSE:To prevent an increase in weight of the head of a golf club even if the head surface area is increased, and reduce the air resistance by providing a plurality of through holes from the surface making contact with a ball of the head to the rear side. CONSTITUTION:Circular holes are bored from the surface making contact with a ball of a head to the rear side. Holes of optional forms such as vertical elliptic holes, horizontal elliptic holes, and square holes are bored so that the air resistance is minimized and the head can be straightly swung. The through hole may be formed as gradually enlarged from the surface toward the rear side or conversely minimized, and has a size as never giving the ball spin. This through hole allows a reduction in weight of the head even if the surface area of the head is increased, and as the air is released through the through holes at the time of swing, the air resistance is reduced, and the head speed can be increased.</p> |
