Arrow shaft with internal bracing
The present invention is a lightweight archery arrow having an arrow shaft with internal bracing, an arrow tip, and a nock. The arrow shaft with internal bracing is a cylindrical tube having a plurality of ribs formed along the length of the cylindrical tube. The ribs increase the bending stiffness of the cylindrical tube without adding additional thickness and weight. Due to the increased bending stiffness of the cylindrical tube provided by the ribs the wall thickness of the cylindrical tube may be reduced while still maintaining the bending stiffness comparable to that of an arrow shaft having a thicker wall. The decrease in wall thickness and the reduction of material reduces the weight of the arrow shaft providing an arrow shaft with an exterior diameter and bending stiffness comparable to that of a standard arrow shaft, but being lighter in weight.
1. An internally fluted arrow shaft for an archery arrow or a crossbow bolt, comprising:
a cylindrical tube having an outside diameter, an inside diameter, and a length, the cylindrical tube consisting essentially of a carbon fiber material impregnated with epoxy,
wherein the cylindrical tube has an exterior surface that is substantially smooth, and an interior surface having a plurality of ribs formed thereon, substantially parallel with the length of the cylindrical tube.
2. The arrow shaft of claim 1 , wherein the plurality of ribs span substantially the entire length of the cylindrical tube.
3. The arrow shaft of claim 2 , wherein the shaft includes an insert at at least one end of the cylindrical tube, each insert having an exterior surface with grooves corresponding to the ribs of the arrow shaft, and an interior surface with either a threaded bore or a smooth bore corresponding to the shaft of a standard internally fitted component.
4. The arrow shaft of claim 2 , wherein the shaft includes an arrow tip and a nock, each having a shaft formed with grooves corresponding to the ribs of the arrow shaft.
5. The arrow shaft of claim 1 , wherein the plurality of ribs have a length that is less than that of the cylindrical tube, and a smooth bore opening is provided at at least one end of the cylindrical tube to accommodate a standard internally fitted component.
6. The arrow shaft of claim 1 , wherein the plurality of ribs have at least one of a triangular, circular, quadrilateral, and crescent shape in cross-section.
7. The arrow shaft of claim 1 , wherein three ribs are formed on the interior surface of the cylindrical tube.
8. The arrow shaft of claim 7 , wherein the ribs have a circular shape in cross-section.