Golf club shaft

Abstract

A golf club shaft having an exterior with a non-circular cross-section along at least a portion of its length is disclosed. In one embodiment, the cross-section of the exterior of the shaft along an intermediate portion of the shaft between the butt end and the tip end is non-circular. In this embodiment, the cross-section of the exterior of the shaft at the end regions containing the butt and tip ends of the shaft may be circular. The cross-section of the intermediate portion may be any suitable shape, such as a symmetrical shape. In one version of such an embodiment, the cross-section of the exterior of the shaft along an intermediate portion of the shaft is substantially triangular in configuration.

1 . A golf club shaft having a longitudinal axis, a cross-section, an exterior surface, a butt end, a tip end, a first end portion comprising said butt end, a second end portion comprising said tip end, and an intermediate portion between said first and second end portions, and a length extending from said butt end to said tip end, wherein at least part of said intermediate portion of said shaft has an exterior surface with a cross-section that is substantially triangular in configuration, wherein said substantially triangular cross-section has a periphery formed by three sides that meet at rounded corners, wherein each of said three sides has a substantially equal length, and the three sides are convex outwardly continuously around said periphery, and at least part of the length of said shaft in said first end portion has an exterior surface with a cross-section that is circular. 
   
   
       2 . The golf club shaft of  claim 1  wherein said three sides of said periphery of said substantially triangular cross-section have equal lengths. 
   
   
       3 . The golf club shaft of  claim 1  having an interior surface along at least a portion of its length, and being hollow inside at least a portion of said interior surface. 
   
   
       4 . The golf club shaft of  claim 3  wherein the cross-section of said portion of said interior surface is substantially circular. 
   
   
       5 . The golf club shaft of  claim 4  wherein said substantially circular cross-section of said portion of interior surface comprises at least part of the length of said intermediate portion. 
   
   
       6 . The golf club shaft of  claim 5  wherein the interior surface and exterior surface of the shaft, along said at least part of the length of said intermediate portion, define a wall therebetween, and the wall has portions with different thicknesses. 
   
   
       7 . The golf club shaft of  claim 6  wherein the wall is thicker in the regions of the corners than in the region adjacent the sides. 
   
   
       8 . The golf club shaft of  claim 3  comprising a macroscopically single layer structure. 
   
   
       9 . The golf club shaft of  claim 3  wherein said first end portion, said second end portion, and said intermediate portion of said shaft comprise the same structure and material. 
   
   
       10 . A golf club shaft according to  claim 1  further comprising a club head joined to the second end portion of said shaft and a grip joined to the first end portion of said shaft to form a golf club. 
   
   
       11 . A golf club shaft having a longitudinal axis, an exterior surface, a cross-section, a butt end, a tip end, and a length extending from said butt end to said tip end, said golf club shaft comprising:
 (a) a first end portion comprising the butt end of the shaft wherein the cross-section of the exterior of said shaft along a portion of the length of said shaft extending from said butt end part of the distance toward said tip end is circular;   (b) a second end portion comprising the tip end of the shaft, wherein the cross-section of the exterior of said shaft along a portion of the length of said shaft extending from said tip end part of the distance toward said butt end is circular; and   (c) an intermediate portion between said first and second end portions, wherein the cross-section of the exterior surface of said shaft along at least part of the length of said intermediate portion is substantially triangular in configuration, wherein the substantially triangular cross-section has a periphery formed by three sides that meet at rounded corners, wherein each of said three sides has a substantially equal length, and said three sides are convex outwardly continuously around said periphery.   
   
   
       12 . The golf club shaft of  claim 11  having an interior surface along at least a portion of its length, and being hollow inside at least a portion of said interior surface. 
   
   
       13 . The golf club shaft of  claim 12  wherein the cross-section of said portion of said interior surface is substantially circular. 
   
   
       14 . The golf club shaft of  claim 11  wherein at least one of said first end portion and said second end portion merges into said intermediate portion in a transition region, wherein in said transition region the configuration of the exterior surface of said shaft changes from one configuration to a different configuration over a portion of the length of said shaft. 
   
   
       15 . The golf club shaft of  claim 14  wherein the exterior cross-section of the first end, second end, and intermediate portions of said shaft each have at least one radius of curvature, and said transition region is located where said first end portion merges into said intermediate portion, wherein said transition region comprises:
 (i) a portion of the shaft in which the cross-section has a radius of curvature at three spaced apart locations disposed on the exterior surface of the shaft, wherein the radius of curvature at said three locations decreases from the first end portion toward the intermediate portion; and   (ii) three portions of the perimeter of the cross-section of exterior surface of the shaft that lie between the aforementioned three locations, wherein said three portions of the perimeter of the shaft have a radius of curvature that increases as the shaft transitions from the first end portion to the intermediate portion.   
   
   
       16 . The golf club shaft of  claim 14  wherein the exterior cross-section of the first end, second end, and intermediate portions of said shaft each have at least one radius of curvature, and said transition region is located where said intermediate portion merges into said second end portion, wherein said transition region comprises:
 (i) a portion of the shaft in which the cross-section has a radius of curvature at three spaced apart locations disposed on the exterior surface of the shaft, wherein the radius of curvature at said three locations increases as the shaft transitions from the intermediate portion to the second end portion; and   (ii) three portions of the perimeter of the cross-section of exterior surface of the shaft that lie between the aforementioned three locations, wherein said three portions of the perimeter of the shaft have a radius of curvature that decreases as the shaft transitions from the intermediate portion to the second end portion.   
   
   
       17 . The golf club shaft of  claim 11  wherein said shaft, at any point along its length:
 (i) bends in such a way that the deflection is the same regardless of how the shaft is rotated about its longitudinal axis; and   (ii) twists the same amount in both directions.   
   
   
       18 . A golf club shaft according to  claim 11  further comprising a club head joined to the second end portion of said shaft and a grip joined to the first end portion of said shaft to form a golf club. 
   
   
       19 . A golf club shaft having a longitudinal axis, a cross-section, an exterior surface, a butt end, a tip end, a first end portion comprising said butt end, a second end portion comprising said tip end, and an intermediate portion between said first and second end portions, and a length extending from said butt end to said tip end, wherein at least part of said intermediate portion of said shaft has an exterior surface with a cross-section that is substantially triangular in configuration and has three convex sides that meet at rounded corners, wherein each of said three sides has a substantially equal length, and each side has a radius of greater than the maximum dimension of the shaft at the cross-section, and at least part of the length of said shaft in said first end portion has an exterior surface with a cross-section that is circular.