Improved shaft for golf club

Abstract

A golf club, includes a golf club head; a shaft including a tip end, an opposite butt end, and a reinforced section extending in a tip-to-butt direction from the tip end to 550 mm from the tip end, the golf club head being coupled to the shaft at the tip end, and including a pitch-based carbon fiber ply that is in only the reinforced section; and a grip being coupled to the shaft at the butt end.

What is claimed is: 
     
         1 . A golf club, comprising:
 a golf club head having a club head rearmost point and a club head frontmost point, the golf club head comprising:
 a striking face, 
 a sole extending rearwardly from a bottom side of the striking face to a rearmost point of the sole, the sole having a closing ascent angle that is less than about 35 degrees and is defined as an angle between (1) a line from the rearmost point of the sole to a sole point, of a projected silhouette of the golf club head from a toe-side viewpoint, that is located on the sole and at a set distance from the club head rearmost point, as measured along a ground plane, and (2) a plane that intersects the sole point and is parallel to the ground plane, and 
 a crown extending rearwardly from a topside of the striking face to a rearmost point of the crown; and 
   a shaft comprising:
 a tip end, the shaft being coupled to the golf club head at the tip end, 
 a butt end opposite to the tip end, and 
 a tip end portion extending in a tip-to-butt direction from the tip end to 300 mm from the tip end, a smallest diameter of the shaft in the tip end portion being less than 0.330 inches. 
   
     
     
         2 . The golf club head of  claim 1 , wherein the crown has a closing descent angle that is less than about 35 degrees and is defined as an angle between (1) a line from the rearmost point of the crown to a crown point, of the projected silhouette of the golf club head, that is located on the crown and at a set distance from the club head rearmost point, as measured along the ground plane, and (2) a plane that intersects the crown point and is parallel to the ground plane. 
     
     
         3 . The golf club of  claim 2 , wherein the closing descent angle is within 85% to 115% of the closing ascent angle. 
     
     
         4 . The golf club of  claim 1 , wherein the smallest diameter of the shaft in the tip end portion is less than 0.300 inches. 
     
     
         5 . The golf club of  claim 1 , wherein the shaft comprises:
 a reinforced section extending in a tip-to-butt direction from the tip end to 550 mm from the tip end; and   a pitch-based carbon fiber ply that is in only the reinforced section.   
     
     
         6 . The golf club of  claim 1 , wherein the set distance from the club head rearmost point is one-third of a front-to-back length between the club head rearmost point and the club head frontmost point. 
     
     
         7 . The golf club of  claim 1 , wherein the set distance from the club head rearmost point is one-half of a front-to-back length between the club head rearmost point and the club head frontmost point. 
     
     
         8 . The golf club of  claim 1 , wherein the golf club head further comprises a skirt connected between the crown and the sole,
 wherein the skirt includes an aft skirt portion at a rear of the golf club head, and the aft skirt portion has:
 a lower boundary that is connected to the sole and that has a skirt height above the ground plane that satisfies a ratio of a head length to the skirt height of 3:1 to 8:1, the head length being a length of the golf club head between the club head rearmost point and the club head frontmost point; and 
 a skirt thickness that satisfies a ratio of the head length to the skirt thickness of 6:1 to 11:1, the skirt thickness being a thickness of the aft skirt portion between the crown and the sole. 
   
     
     
         9 . A golf club, comprising:
 a golf club head, comprising:
 a striking face, 
 a sole extending rearwardly from a bottom side of the striking face, 
 a crown extending rearwardly from a topside of the striking face, and 
 a hosel at a heelward side of the golf club head, the hosel including a hosel opening, wherein the hosel comprises:
 a first toeward tripping structure including an elongated ridge or groove having a height or depth of between 0.005 inches and 0.03 inches and extending in a direction from the hosel opening towards the sole; and 
 a first heelward tripping structure including an elongated ridge or groove having a height or depth of between 0.005 inches and 0.03 inches and extending in the direction from the hosel opening towards the sole; and 
 
   a shaft coupled to the golf club head at the hosel opening, the shaft comprising:
 a tip end inserted into the hosel opening, and 
 an opposite butt end, 
   wherein an average bending stiffness of a butt end portion of the shaft is greater than 3.70 times an average bending stiffness of a tip end portion of the shaft.   
     
     
         10 . The golf club of  claim 9 , wherein the tip end portion extends in a tip-to-butt direction from 150 mm from the tip end to 300 mm from the tip end, and
 wherein the butt end portion extends in the tip-to-butt direction from 800 mm from the tip end to 950 mm from the tip end.   
     
     
         11 . The golf club of  claim 9 , wherein the shaft further comprises a pitch-based carbon fiber ply that is at least partially in the tip end portion. 
     
     
         12 . The golf club of  claim 11 , wherein the pitch-based carbon fiber ply is in only the tip end portion. 
     
     
         13 . The golf club of  claim 9 , wherein the first heelward tripping structure is spaced apart from the first toeward tripping structure by 70-170 degrees, as measured around a shaft axis of the shaft. 
     
     
         14 . The golf club of  claim 9 , wherein the first toeward tripping structure is positioned at a shaft-axis angular position of 0-80 degrees measured around a shaft axis of the shaft,
 wherein the first heelward tripping structure is positioned at a shaft-axis angular position of 260-340 degrees measured around the shaft axis, and   wherein a 0 degree shaft-axis angular position corresponds to a direction forward of the golf club head and perpendicular to a plane defined by the striking face.   
     
     
         15 . The golf club of  claim 9 , wherein the golf club head comprises:
 second and third toeward tripping structures, each located within 30 degrees of the first toeward tripping structure; and   second and third heelward tripping structures, each located within 30 degrees of the first heelward tripping structure.   
     
     
         16 . A golf club, comprising:
 a golf club head, comprising:
 a striking face, the striking face defining a frontmost point of the golf club head; 
 a sole extending rearwardly from a bottom side of the striking face; and 
 a crown extending rearwardly from a top side of the striking face, 
 wherein an aft slice of the golf club head is a portion of the golf club head rearward of a slice line and between an outer perimeter of the golf club head and an offset perimeter slice curve, 
 wherein the slice line extends in a heel-to-toe direction and is located at a slice depth rearward from the frontmost point, and the offset perimeter slice curve is offset from the outer perimeter of the golf club head by a perimeter offset distance, 
 wherein the aft slice has at least one of the following dimensions:
 a centroid height that is at least 50% of a height of the golf club head above a ground plane; or 
 a smallest height that is at least 40% of the height of a geometric center of the striking face above the ground plane; and 
 
   a shaft coupled to the golf club head, the shaft comprising:
 a tip end, 
 an opposite butt end, 
 a reinforced section extending in a tip-to-butt direction from the tip end to 550 mm from the tip end, and 
 a first pitch-based carbon fiber ply that is in only the reinforced section. 
   
     
     
         17 . The golf club of  claim 16 , wherein the shaft further comprises a second pitch-based carbon fiber ply that extends substantially along a full length of the shaft. 
     
     
         18 . The golf club of  claim 16 , wherein the shaft further comprises a second pitch-based carbon fiber ply,
 wherein the first pitch-based carbon fiber ply is a substantially 45 degree ply, and   wherein the second pitch-based carbon fiber ply is a substantially negative 45 degree ply.   
     
     
         19 . The golf club of  claim 16 , wherein the slice depth is equal to 70% of a front-to-back length of the golf club head and the offset perimeter slice curve is offset from the outer perimeter of the golf club head by 0.5 inches. 
     
     
         20 . The golf club of  claim 16 , wherein the slice depth is equal to 60% of a front-to-back length of the golf club head and the offset perimeter slice curve is offset from the outer perimeter of the golf club head by 1.0 inches.