Flex-segmented golf club shaft and method of manufacture

Abstract

A flex-segmented golf club shaft having tip and butt sections of preselected stiffness and flex characteristics, respectively, that are formed as separate pieces, with the larger butt section overlapping and fused to the smaller tip section and forming an external step in the shaft profile. An alternative embodiment has three such sections and two steps. The method of forming the shaft by wrapping a preselected tip section from a selection of available sections on a mandrel having a pronounced step, and then wrapping a preselected butt section from a selection of available sections on the mandrel in overlapping relation with the tip section, to provide optimized characteristics for a particular golf swing.

1 . The method of producing a golf club shaft made up of a butt section and a tip section having optimized performance characteristics for a particular golf swing, comprising the steps of: 
 providing a selection of at least two different tip sections for said shaft having different predetermined stiffness characteristics;    providing a selection of at least two different butt sections for said golf shaft having different predetermined flex characteristics;    producing a selected one of said tip sections as a separate segment having at one end portion for connection to a club head and a second end portion for connection to a butt section;    and producing a selected one of said butt sections as a separate part having one end portion disposed around and overlapping with the selected tip section and securely joined thereto, whereby the resulting shaft has performance characteristics determined by the combination of the selected tip section and the selected butt section.    
   
   
       2 . The method defined in  claim 1  wherein said steps of producing the selected butt section and the selected tip section are performed by wrapping composite material on a mandrel having tip and butt end portions of smaller and larger sizes, respectively, joined by a discrete step and designed to produce the selected tip and butt sections of the shaft, the selected tip section being wrapped on the smaller end portion of the mandrel with said one end portion against said discrete step and the selected butt section being wrapped on the larger end portion of the mandrel and extending a predetermined distance beyond said step to overlap said one end portion of the tip section.  
   
   
       3 . The method defined in  claim 1  wherein said selection of tip sections comprises tip sections having at least three different stiffness characteristics and said selection of butt sections comprises butt sections having at least three different flex characteristics.  
   
   
       4 . The method defined in  claim 3  wherein said different tip sections have stiffness characteristics for low launch, mid launch and high launch, and said different butt sections have flex characteristics that are low, medium and high flexes.  
   
   
       5 . The method defined in  claim 3  wherein each of said selections comprises different tip sections and different butt sections for at least two different weights of club for each selected combination.  
   
   
       6 . (canceled)  
   
   
       7 . (canceled)  
   
   
       8 . (canceled)  
   
   
       9 . (canceled)  
   
   
       10 . (canceled)  
   
   
       11 . (canceled)  
   
   
       12 . (canceled)  
   
   
       13 . A flex-segmented golf club shaft having tip and butt sections, comprising: 
 an elongated tip section of predetermined length and preselected stiffness characteristics composed of composite material and having one end portion for connection to a golf club head and a second end portion for connection to the butt section;    an elongated butt section composed of composite material and having one end portion disposed around and overlapping said second end portion of said tip section and securely joined thereto and having preselected flex characteristics;    and a step in the outside surface of said shaft at the end of said one end portion of said butt section;    said butt and tip sections being separate pieces joined together by the overlapping end portions whereby each section may be designed for optimized performance characteristics for a particular golf swing.    
   
   
       14 . A flex-segmented golf club shaft as defined in  claim 13  wherein said tip section and said butt section are tubular composite parts, the outside diameter of said second end portion of said tip section and the inside diameter of said one end portion of said butt section being the same and being fused together.  
   
   
       15 . A flex-segmented golf club shaft as defined in  claim 13  wherein said butt section overlaps said tip section by a preselected distance sufficient to join the sections securely together without interfering with the flexibility of the shaft.  
   
   
       16 . A flex-segmented golf club shaft as defined in  claim 15  wherein said preselected distance is in the range of approximately four inches to approximately six inches.  
   
   
       17 . A flex-segmented golf club shaft as defined in  claim 15  wherein said preselected distance is between a minimum of one inch and a maximum of eight inches.  
   
   
       18 . A flex-segmented golf club shaft as defined in  claim 13  wherein said butt section comprises an intermediate section joined to said tip section and an end section overlapping and joined to said intermediate section.  
   
   
       19 . A flex-segmented golf club shaft as defined in  claim 13  wherein said step in the outside surface has a preselected contour selected from the group comprising a shoulder normal to the shaft axis, a taper, concavely rounded, and convexly rounded.