Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Spiral-grooved arrow shaft

Spiral-grooved arrow shaft description/claims

1. Field of the Invention

The present invention relates to the field of archery. Specifically, the invention relates to the arrow shaft component of arrow devices.

2. Description of the Prior Art

The flight path of an arrow assembly must be predictable in order for an archer to strike an intended target. The arrow should not float or drift from the path along which it was aimed.

Prior art arrow assemblies have relied upon the aft or forward end to provide this guidance. The most ancient of these technologies is the uniformly spaced application of two, three, or even more feathers, also referred to as fletches or vanes, about the aft end of the arrow assembly. These fletches steer the arrow assembly from behind like the rudder of a ship. The arrow assembly is essentially pushed through the air. This pushing can cause the flight path of the arrow assembly to wander as the arrow assembly is affected by random influences such as crosswind, oscillating vibration of the arrow shaft, and asymmetries between the arrow vanes' mass or installation position. One recent improvement is the vane of Kuhn (U.S. Pat. No. 6,695,727) that employs vanes whose geometry imparts an axial rotational spin on the arrow assembly during flight

The use of aerodynamic influences at the forward end of an arrow assembly has been less deliberate in the prior art until recently. So-called field point arrowheads are very simple devices that are commonly used for target practice. Field point arrowheads taper from a maximum diameter, equal to approximately the diameter of the arrow shaft, down to a point at the forwardmost end. This prior art arrowhead has a negligible aerodynamic effect as the arrow assembly flies towards its intended target.

Broadhead arrowheads were invented to increase effective hunting penetration and success potential. Typically two to four flat, triangular blades are arranged around the forward pointed tip. These broad, flat blades have a pronounced aerodynamic effect that can radically affect the overall stability of the arrow in flight and significantly reduce the precision of flight. Typical incarnations of such broadheads are described in the patents of Newnam (U.S. Pat. No. 5,636,845) or Musacchia (U.S. Pat. No. 4,621,817). One recent improvement is the broadhead of Kuhn (U.S. Pat. No. 6,663,518) that employs blades whose deliberate, aerodynamically active geometry imparts an axial rotational spin on the arrow assembly during flight. Such inventions are improvements over the fletching technologies because they provide steering from the leading end of the arrow. Asymmetries encountered during flight tend to be damped out by the trailing rotational inertia of the shaft. One drawback of these technologies is that the arrowheads can be easily damaged and may be rendered useless after a single shot. Manufacturing tolerances must also be strict in order to produce a product that has consistent aerodynamic qualities.

Spin-stabilization is clearly a desirable feature for any successful arrow assembly. Unfortunately, the competing aerodynamic effects of the aft end and forward end enhancements described above can render each other unsuccessful. Furthermore, individual archers may prefer features found in certain vanes or arrowheads; such features may not be included in commercially available products. The prior art lacks teaching of a spin-stabilizing arrow shaft as a part of an arrow assembly. Such a shaft could be assembled with an archer's choice of vanes and arrowhead while still providing adequate spin stabilization to promote accurate flight.

The present invention is a spirally grooved arrow shaft that imparts axial rotation to an arrow assembly. The shaft has a plurality of substantially identical, helical, longitudinal channels along its outer surface extending down a substantial portion of the arrow shaft along its primary axis. The channels may consist of a plurality of grooves cut into the outer surface of the arrow shaft. Alternatively, the channels may be formed from a plurality of raised fins or raised members that extend radially outward from the surface of the shaft. The invention is compatible with all contemporary arrowheads and vanes provided that all aerodynamic surfaces present on these devices urge rotation of the arrow assembly in the same direction as the spiral channels.

FIG. 1 shows an oblique longitudinal view of the present invention.

FIG. 2 shows a cross-sectional view of a first embodiment of the present invention. The cross-section is perpendicular to the major axis of the arrow shaft.

FIG. 3 shows a cross-sectional view of a second embodiment of the present invention. The cross-section is perpendicular to the major axis of the arrow shaft.

With reference to FIGS. 1 through 3, arrow shaft 1 of the invention comprises a typically cylindrical body of substantially uniform diameter with a first end 2 and a second end 3. Shaft 1 is typically symmetrical about the longitudinal axis and may be manufactured from any suitable structural material known in the art such as steel, aluminum, carbon fibers, plastic or a composite of materials. Any arrowhead known in the art may be attached by typical attachment means (not depicted) to first end 2. Typically, such an attachment means comprises a female-threaded socket that is press-fitted or glued into first end 2 of arrow shaft 1. This socket mechanically engages the arrowhead to arrow shaft 1. Any fletches known in the art may be attached to second end 3 by typical attachment means known in the art such as gluing.

• Provisional Patent
• Utility Patent

• What Is a Patent?
• What Is a Trademark or Servicemark?
• What Is a Copyright?
• Patent Laws