Small Diameter High Straightness Arrow and Method of Manufacture for the Same

Abstract

The small diameter high straightness arrow made by the process of present invention is designed to improve the stiffness and straightness of the small diameter archery arrows. A chamber and a mandrel are made of dissimilar metals. The chamber includes walls creating an external housing and defining an internal airspace. Once the mandrel covered with carbon fiber is positioned through chamber, the mandrel ends are secured, forming an assembly, to straighten mandrel. When heated simultaneously, the different coefficients of thermal expansion of chamber and mandrel cause the chamber to expand more than the mandrel, creating a natural tension along mandrel resulting in a near perfectly straight shaft. As the assembly cools, the mandrel and chamber return to their original length, yet the shaft retains its straightened form. The manufacturing process yields an arrow shaft that is straighter than shafts made of the same materials but with a traditional manufacturing technique.

What is claimed is: 
     
         1 . A small diameter high straightness arrow shaft with a longitudinal axis comprising:
 a plurality of non-standard modulus carbon fiber filaments longitudinally oriented at zero degrees from said longitudinal axis, wherein said non-standard modulus carbon fiber filaments form a tubular shaft having a length;   a plurality of standard modulus carbon fiber filaments oriented at a hoop angle from said longitudinal axis, wherein said plurality of standard modulus carbon fiber filaments circumscribes said plurality of non-standard modulus carbon fiber filaments spanning said length; and   wherein small diameter high straightness arrow shaft has an exterior diameter of at most 0.250 inches, a straightness tolerance of plus or minus 0.001 inches, and a spine equal to an arrow shaft having an external diameter greater than 0.250 inches.   
     
     
         2 . The small diameter high straightness arrow of  claim 1 , wherein said hoop angle is ninety (90) degrees. 
     
     
         3 . The small diameter high straightness arrow of  claim 1 , wherein said non-standard modulus carbon fiber filaments has a modulus of between 50 msi and 60 msi. 
     
     
         4 . The small diameter high straightness arrow of  claim 1 , wherein said non-standard modulus carbon fiber filaments has a modulus of between 40 msi and 45 msi. 
     
     
         5 . The small diameter high straightness arrow of  claim 1 , wherein said standard modulus carbon fiber filaments has a modulus of between 30 msi and 39 msi. 
     
     
         6 . The small diameter high straightness arrow of  claim 1 , father comprising an interior diameter between 0.170 inches and 0.150 inches. 
     
     
         7 . The small diameter high straightness arrow of  claim 1 , further comprising a wall thickness of at least 0.05 inches. 
     
     
         8 . A small diameter high straightness arrow shaft comprising:
 a sheet wrapped carbon shaft having a longitudinal axis wherein said sheet wrapped carbon shaft comprises:   a non-standard modulus unidirectional carbon fiber material oriented substantially parallel in a lengthwise direction to said longitudinal axis;   a standard modulus unidirectional carbon fiber material oriented at a hoop angle to said longitudinal axis; and   wherein small diameter high straightness arrow shaft has an exterior diameter of at most 0.250 inches, a straightness tolerance of plus or minus 0.001 inches, and a spine equal to an arrow shaft having an external diameter greater than 0.250 inches.   
     
     
         9 . The small diameter high straightness arrow of  claim 8 , wherein said hoop angle is ninety (90) degrees. 
     
     
         10 . The small diameter high straightness arrow of  claim 8 , wherein said non-standard modulus carbon fiber filaments has a modulus of between 50 msi and 60 msi. 
     
     
         11 . The small diameter high straightness arrow of  claim 8 , wherein said non-standard modulus carbon fiber filaments has a modulus of between 40 msi and 45 msi. 
     
     
         12 . The small diameter high straightness arrow of  claim 8 , wherein said standard modulus carbon fiber filaments has a modulus of between 30 msi and 39 msi. 
     
     
         13 . The small diameter high straightness arrow of  claim 8 , further comprising an interior diameter between 0.170 inches and 0.150 inches. 
     
     
         14 . The small diameter high straightness arrow of  claim 1 , further comprising a wall thickness of at least 0.05 inches per wall. 
     
     
         15 . A small diameter high straightness arrow shaft having a longitudinal axis comprising:
 a non-standard modulus unidirectional carbon fiber material sheet having non-standard modulus carbon filaments oriented in a lengthwise direction at a axial angle to said longitudinal axis and formed as a tubular shaft;   a standard modulus unidirectional carbon fiber material sheet having standard modulus carbon filaments oriented in a lengthwise direction to at a hoop angle to said longitudinal axis, said standard modulus unidirectional carbon fiber material sheet circumscribing said tubular shaft; and   wherein small diameter high straightness arrow shaft has an exterior diameter of at most 0.250 inches, a straightness tolerance of plus or minus 0.001 inches, and a spine equal to an arrow shaft having an external diameter greater than 0.250 inches.   
     
     
         16 . The small diameter high straightness arrow of  claim 15 , wherein said axial angle is zero degrees and said hoop angle is ninety degrees. 
     
     
         17 . The small diameter high straightness arrow of  claim 15 , wherein said non-standard modulus carbon fiber filaments has a modulus of between 50 msi and 60 msi. 
     
     
         18 . The small diameter high straightness arrow of  claim 15 , wherein said non-standard modulus carbon fiber filaments has a modulus of between 40 msi and 45 msi. 
     
     
         19 . The small diameter high straightness arrow of  claim 15 , wherein said standard modulus carbon fiber filaments has a modulus of between 30 msi and 39 msi. 
     
     
         20 . The small diameter high straightness arrow of  claim 8 , further comprising an interior diameter between 0.170 inches and 0.150 inches and a wall thickness of at least 0.100 inches.