GOLF CLUB HEAD AFT BODY CONSTRUCTION

1 . A golf club head comprising:

a face portion having a striking face; and

an aft body located rearward of said face portion;

said aft body comprising:

a crown portion;

a sole portion opposite said crown portion; and

a skirt portion formed between an outer perimeter portion of said crown portion and an outer perimeter portion of said sole portion,

wherein a face center of said striking face defines an origin of a coordinate system, said coordinate system having an x-axis extending in a heel-to-toe direction, a y-axis extending in a crown-to-sole direction and perpendicular to said x-axis, and a z-axis extending in a front-to-rear direction and perpendicular to said x-axis and said y-axis,

wherein a hoop-direction is defined as a 360 degree path around said aft body which extends in said heel-to-toe direction along said crown portion, in said crown-to-sole direction over a toe-side section of said skirt portion, in said heel-to-toe direction along said sole portion, and in said crown-to-sole direction over a heel-side section of said skirt portion,

wherein at least a portion of said aft body is made of a composite material having carbon fibers, and

wherein at least 50% of said carbon fibers are hoop-direction oriented fibers.

2 . The golf club head of claim 1 , wherein a forwardmost portion of said composite material is located within 1.5 inches from said striking face.

3 . The golf club head of claim 1 , wherein said at least a portion of said aft body includes at least part of said crown portion, at least part of said toe-side section of said skirt portion, at least part of said sole portion, and at least part of said heel-side section of said skirt portion.

4 . The golf club head of claim 1 , wherein said composite material comprises a stack of unidirectional fiber plies.

5 . The golf club head of claim 4 , wherein said hoop-direction oriented fibers are included in alternating layers of said stack of unidirectional fiber plies.

6 . The golf club head of claim 1 , wherein said hoop-direction oriented fibers are part of woven fiber plies.

7 . The golf club head of claim 1 , wherein at least 55% of said carbon fibers are hoop-direction oriented fibers.

8 . A golf club head comprising:

a face portion having a striking face; and

an aft body located rearward of said face portion;

said aft body comprising:

a crown portion;

a sole portion opposite said crown portion; and

a skirt portion formed between an outer perimeter portion of said crown portion and an outer perimeter portion of said sole portion,

wherein a face center of said striking face defines an origin of a coordinate system, said coordinate system having an x-axis extending in a heel-to-toe direction, a y-axis extending in a crown-to-sole direction and perpendicular to said x-axis, and a z-axis extending in a front-to-rear direction and perpendicular to said x-axis and said y-axis,

wherein at least a portion of said aft body comprises a composite material having fibers, and

wherein at least 50% of said fibers are oriented substantially perpendicular to said z-axis.

9 . The golf club head of claim 8 , wherein a forwardmost portion of said composite material is located within 1.5 inches from said striking face.

10 . The golf club head of claim 9 , wherein at least 55% of said fibers are oriented substantially perpendicular to said z-axis.

11 . The golf club head of claim 10 , wherein said at least a portion of said aft body includes at least part of said crown portion, at least part of said sole portion, and at least part of said skirt portion.

12 . The golf club head of claim 11 , wherein said composite material comprises a stack of unidirectional fiber plies.

13 . The golf club head of claim 12 , wherein alternating layers of said stack of unidirectional fiber plies consist of said fibers oriented substantially perpendicular to said z-axis.

14 . The golf club head of claim 11 , wherein said fibers oriented substantially perpendicular to said z-axis are part of woven fiber plies.