1. Field of the Invention
This invention relates to an element for an archery arrow or a bolt, having airfoils or other airflow resistors to generate rotation of an arrow shaft about its longitudinal axis, to increase rotation and stability of the arrow shaft, and to improve flight accuracy.
2. Discussion of Related Art
Conventional archery arrows for bows and bolts for crossbows may not provide a significant amount of rotational spin during arrow flight, resulting in poor arrow stability during flight and/or poor arrow flight accuracy.
In an effort to increase rotation of the arrow, some conventional vanes or fletching use helical vanes. However, a decreased clearance between vanes can cause interference with an arrow rest of a bow, particularly during launch. Any interference can cause the arrow to change direction when shot from the bow or to wobble during flight, resulting in decreased accuracy and/or flight distance. Because of a required offset position, arrows having helically oriented archery vanes, such as those positioned at an angle with respect to a longitudinal axis of an arrow shaft, are difficult to manufacture.
Some known vanes have a different surface texture or roughness on each side of the vane, which creates a lift force and imparts rotation along a longitudinal spin axis of the arrow. Vanes with different roughnesses on each side can be positioned generally parallel to the longitudinal axis of the arrow shaft and thus are simpler to manufacture, such as those taught by U.S. Pat. No. 6,142,896, the teachings of which are incorporated into this specification by reference.
A conventional arrowhead that rotates is taught by U.S. Pat. No. 7,037,222, the teachings of which are incorporated into the specification by reference. A rotating arrowhead can also be accomplished with a known winglet or spintab that acts like an airfoil to create lift and rotational forces. There can be additional costs associated with the manufacture of arrowheads with a winglet or a spintab.
There is an apparent need for an arrow element which generates rotation of the arrow shaft about a longitudinal axis to provide increased rotation and increased stability to the arrow shaft, and to improve flight accuracy of the arrow.
It is also apparent that there is a need for an arrow element that is cost effective, easy to produce, simple to install and that enhances aerodynamic flight.