Games using tangible projectile – Projectile – per se; part thereof or accessory therefor – Arrow – dart – or shuttlecock; part thereof
Reexamination Certificate
2001-04-16
2004-06-01
Ricci, John A. (Department: 3712)
Games using tangible projectile
Projectile, per se; part thereof or accessory therefor
Arrow, dart, or shuttlecock; part thereof
C030S357000
Reexamination Certificate
active
06743128
ABSTRACT:
BACKGROUND—FIELD OF THE INVENTION
This invention relates generally to cutting blades, sharper cutting blades and particularly to sharper arrowhead or broadhead cutting blades.
BACKGROUND—DESCRIPTION OF PRIOR ART
Arrows have long been used for war, hunting and competitive sports. A conventional arrow has a shaft, a nock at one end that receives the bow string, an arrowhead or point that attaches to the opposite end, and fletchings. The fletchings are glued to the shaft near the nock end, and help to stabilize the arrow in flight by causing it to rotate. Arrowheads generally have a pointed forward end, and an opposite threaded shaft end that attaches the arrowhead to the arrow shaft. Arrowheads are also attached to the forward end of arrow shafts by glueing and other methods.
Arrowheads come in a variety of different sizes and configurations depending on their intended use. For example, there are specifically designed arrowheads for competitive target shooting, shooting fish, hunting birds or small game animals, and for hunting big game animals.
Arrowheads used for hunting generally kill the game animal by cutting vital organs such as the lungs and vascular vessels such as arteries, which causes rapid hemorrhaging and/or suffocation. Quick and humane kills are dependent on accurate shot placement, and upon the amount or volume of the animal tissue that is cut. Hunting arrowheads that cut more tissue are more lethal, and therefore are better. The volume of tissue that is cut is determined by the cutting diameter of the arrowhead, the number of blades it contains, and by the distance the arrowhead penetrates into the animal. The sharper the cutting edge of the arrowhead blade(s) (all other factors being equal) the greater the depth of penetration will be.
A cutting edge of a cutting blade, such as those used with hunting arrowheads is formed on a section of blade-stock material by grinding or otherwise fabricating an acute angle along an edge of the blade stock material. This process usually forms a bevel or bevels on both opposing side faces of the blade-stock material. Generally, the sharpness of an arrowhead cutting blade (all other factors being equal) is determined by the angle between opposing bevels on either side of the cutting edge of the blade; the narrower the angle between the opposing bevels the sharper the cutting edge is. A common method for manufacturing arrowhead blades is the process of strip grinding, wherein generally a pair of primary grind bevels is first ground on opposing sides of the metal strip (blade stock material) so that an acute angle (the cutting edge) is created along an edge of strip, whereupon a pair of hone grind bevels is generally ground on the primary grind bevels so as to yet further define the cutting edge with another acute angle, and lastly the cutting edge is generally stropped—wherein microscopic burrs are removed from the cutting edge.
A common type of arrowhead used in hunting is the fixed-blade arrowhead, which has a pointed tip end used for penetrating, and generally triangular shaped fixed-blades or non-pivotal blades that each have a razor sharp edge for cutting. Conventional fixed-blade arrowheads blades are held in a fixed position on the arrowhead, and most such blades are replaceable. The replaceable blades attach to the arrowhead body in longitudinal grooves called blade slots. The tip of the arrowhead may be separably attachable to the arrowhead body or may be integral with it. Arrowheads for hunting are generally known as broadheads. Some types of fixed-blade arrowheads have a cutting blade extending to the forward terminus of the arrowhead, such as flathead arrowheads and traditional cut-on-contact arrowheads.
Another popular type of arrowhead for hunting is the blade-opening arrowhead. Blade-opening arrowheads are generally known as mechanical broadheads. Blade-opening arrowheads, like conventional fixed-blade arrowheads generally have an elongate arrowhead body, a tip end, and a threaded opposite end. The blades of blade-opening arrowheads have an attachment end which attaches the blades to the arrowhead body by a shaft or a pivot pin, so that the blades can pivot, rotate or expand between a closed position and an open position. Blade-opening arrowhead blades are generally an elongate substantially rectangular shape and also have a free non-attached end situated opposite the attachment end. The blades of blade-opening arrowheads are also received in blade slots, which are machined or formed into the arrowhead body. The expandable or pivotal blades of blade-opening arrowheads are held in the closed position while in-flight, until the arrowhead penetrates a game animal or target, by various different methods including: conventional rubber O-rings, rubber bands, tight fitting plastic sleeves, tape, heat-shrinkable sleeves, and other wrap materials as well as by magnetism, various spring systems, friction detents and other frictional mechanisms. When the expanding blades of blade-opening arrowheads are retracted or folded into the closed position, a substantial majority of each blade is generally housed within its corresponding blade slot. This feature gives blade-opening arrowheads the ability to attain significantly increased aerodynamic performance over fixed-blade arrowheads, due to the significantly decreased exposure the retracted blades have with the air when the arrow is rotating while in flight. Such increased aerodynamic performance results in the desirable features of: faster shooting arrows, flatter arrow trajectories, increased penetration energy and enhanced repeatability of accuracy, while also providing a wide diameter cut in the game animal when the razor sharp blades open at impact with the animal.
Blade-opening arrowheads come in a variety of different types and styles. The most common type of blade-opening arrowhead has blades that are pivotally connected to the arrowhead body at a location near the rear end of the arrowhead body. This makes it so that when the blades are folded into the retracted position a leading blade end of each blade positioned near the tip of the arrowhead protrudes outward from the arrowhead body. The leading blade ends of such blade-opening arrowheads rotate or expand away from the arrowhead body in a rearward direction when penetrating an animal. Particularly, the leading blade ends catch on the animal's surface and serve to lever or rotate the blades into the fully open position, thus exposing the sharp cutting edges of the blades to a fully open cutting diameter position and cutting the animal. Another type of blade-opening arrowhead has pivotal blades that rotate or expand in a forward direction to the fully open position when penetrating an animal. The blades of these forward blade rotating/expanding blade-opening arrowheads are rotated or expanded toward the open position by a variety of different mechanisms, but all also define a fully open cutting diameter when in the open position.
Yet another type of arrowhead used for hunting has pivotal blades that are exposed at a full cutting diameter position while the arrowhead is in-flight. Such arrowheads also generally achieve better aerodynamic performance than fixed-blade arrowheads because by design each pivotal blade only attaches to a corresponding arrowhead body at a single location so that with their substantially elongate shaped blades such arrowheads have significantly decreased blade surface area exposure with the air while in-flight.
Arrowheads having expanding blades, or cutting blades attached to an arrowhead body by a pin or a shaft, like most blade-opening arrowheads, generally need to have thicker blades for strength purposes than that of fixed-blade arrowhead blades. This is such because expanding or pivotal blades are generally attached to corresponding arrowhead bodies at only one location (the pin) and therefore can more readily be damaged by the high impact forces encountered at target penetration from impacting bone and/or other similar materials than can the blades of fixed-blades arrowheads which a
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