Games using tangible projectile – Projectile – per se; part thereof or accessory therefor – Arrow – dart – or shuttlecock; part thereof
Reexamination Certificate
2001-01-06
2004-06-29
Ricci, John A. (Department: 3712)
Games using tangible projectile
Projectile, per se; part thereof or accessory therefor
Arrow, dart, or shuttlecock; part thereof
C473S583000
Reexamination Certificate
active
06755758
ABSTRACT:
BACKGROUND
1. Field of the Invention
This invention relates to arrowheads that have opening blades, and more particularly to non-consumable blade retention for retaining a pivotal blade of a blade-opening arrowhead in the retracted position by methods that are not dependent upon the use of an element or elements in addition to that individual cutting blade, its hinge pin and its blade slot, so that when the arrowhead penetrates an object the blade freely rotates to an open position.
2. 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, as it rotates. 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.
The most common type of arrowhead used in hunting is the fixed-blade arrowhead, which has a pointed tip end used for penetrating, and 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.
Arrowheads used for hunting, 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 cutting diameter of an arrowhead is determined by how far each cutting blade extends outward from the arrowhead body. The further the blades extend outward the larger the cutting diameter is, and therefore the more cutting potential the arrowhead has.
A problem with conventional fixed-blade arrowheads is that having the desirable, large cutting diameters generally cause unstable arrow flight or poor arrow aerodynamics, which affects accurate shot placement. This can lead to non-lethal wounding of the game animal or missing the animal altogether. Unstable arrow flight in hunting arrows is generally caused by arrowhead aligning and centering problems. Arrowhead aligning and centering problems are prevalent when the arrowhead is attached to the arrow shaft such that the longitudinal axis of the arrowhead is not in line with the longitudinal axis of the arrow shaft. Alignment and centering problems in arrowheads are generally created by low tolerances or sloppiness in the manufacturing of the arrowhead body. When a mis-aligned arrowhead is attached to an arrow and the arrow is shot, as the arrow spins or rotates in flight non-stabilizing forces are induced on the front end of the arrow and cause inconsistent or erratic flight, which steers the arrow from its intended path. Since the cutting blades of fixed-blade arrowheads extend out from the arrowhead body when the arrowhead is in flight, the blades greatly magnify any non-stabilizing forces induced on the arrow from mis-alignment, and therefore increase erratic arrow flight. This in the main reason why conventional fixed-blade arrowheads are limited in the maximum cutting diameter they can have, while retaining sufficiently stable aerodynamics.
To create a hunting arrowhead that has both a maximum cutting diameter and stable aerodynamics, despite moderate manufacturing tolerances, blade-opening arrowheads were designed. Blade-opening arrowheads differ from conventional fixed-blade arrowheads in that the cutting blades are folded up or held adjacent to the arrowhead body in a retracted position while the arrow is in flight, but at impact with the game animal rotate or pivot into an open position, therefore exposing the sharp blade edges and cutting the animal. Since the blades of blade-opening arrowheads are held adjacent to the arrowhead body and do not extend very far out from it, any aligning or centering problems of a blade-opening arrowhead attached to an arrow will not noticeably steer the arrow or undesirably affect its flight trajectory. In this manner blade-opening arrowheads can have both a desirable large cutting diameter, and the stable arrow flight characteristics necessary for accurate shot placement. Blade-opening arrowheads can therefore potentially be more lethal.
Blade-opening arrowheads, like conventional fixed blade arrowheads generally have an elongated 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 pivot pin, so that the blades can pivot or rotate in a plane between a first selectable position—the retracted position, and a second selectable position—the open position. Blade-opening arrowheads also come in a variety of different types and styles. The blades of the most common type of blade-opening arrowheads, when in the retracted position have a leading blade end positioned near the tip of the arrowhead that protrudes outward from the arrowhead body, and is sometimes shaped like a wing. The leading blade ends of the most common type of blade-opening arrowheads, rotate 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 open position, thus exposing the sharp cutting edges of the blades and cutting the animal. The blades of blade-opening arrowheads are also received in blade slots, which are machined or formed into the side of the arrowhead body.
Blade-opening arrowheads for hunting big game must be non-barbing, wherein the blades when in the open position must not inhibit or prevent arrow extraction from a game animal by barbing into the animal tissue. This makes it so non-fatally wounded animals can easily pull out an arrow still lodged in them. For a blade-opening arrowhead to be non-barbing, the pivotal blades must rotate forward from the open position to an angle greater than ninety degrees, as measured between the rear edge of each blade and a location on the arrow shaft rearward of the blades.
Blade-opening arrowheads generally do not penetrate as deep as conventional fixed-blade arrowheads. This has a variety of causes, one in particular occurs when the blades are non-radially aligned with respect to the longitudinal axis of the arrowhead body such that a net pulling force is exerted on each blade when penetrating an object which causes the arrowhead to spin or twist. Spinning reduces penetration by driving the flat blade sides into uncut tissue, which causes friction and therefore depletes kinetic energy that could otherwise further penetration. Non-radial blade alignment is created when the blades are not situated in line with a radius line extending from the longitudinal center of mass of the arrowhead body or the longitudinal axis, to the exterior surface of the arrowhead body. The rate of spin or the spin capacity of conventional blade-opening arrowheads is limited to the extent of the pulling force exerted upon on the arrowhead body by
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