Patent Application
20160298945
This invention relates generally to projectiles. Specifically, it relates to an improved projectile for use in an air gun or bow.
To further clarify the above and other aspects of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The drawings are not drawn to scale. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
The following detailed description of exemplary embodiments of the invention makes reference to the accompanying drawings, which form a part hereof and in which are shown, by way of illustration, exemplary embodiments in which the technology may be practiced. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the technology may be made without departing from the spirit and scope of the present invention. Thus, the following more detailed description of the embodiments of the present technology is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the present technology, to set forth the best mode of operation of the technology, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the present invention is to be defined solely by the appended claims.
The following detailed description and exemplary embodiments of the invention will be best understood by reference to the accompanying drawings, wherein the elements and features of the invention are designated by numerals throughout.
The present technology in its various embodiments, some of which are depicted in the figures herein, can be broadly described as an improved projectile having a tip disposed about the end of a shaft and butt elements disposed about the rear end of the shaft. In one aspect, a stabilizer member is disposed apart from the butt element. However, in another aspect, the butt also comprises a stabilizer member. Broadly speaking, the technology resides in a shaft with a tip sized to be slightly larger than the diameter of a rifle bore so as to stop further downward movement of the elongate projectile shaft within the bore. A cylindrical butt is disposed about the rear end of the elongate projectile shaft having a front face that induces a predetermined amount of drag about the butt. A cylindrical stabilizer can be disposed forward of the butt and also has a front face that induces an amount of drag about the stabilizer. Advantageously, the enhanced drag about the front face of the butt/stabilizer functions to “center” the elongate projectile while in flight, increasing the ability of the elongate projectile to travel straight to its intended target. While an elongate air projectile for use in an air gun is specifically referenced herein, one of ordinary skill in the art will recognize that the technology can be used in connection with an arrow used in a traditional bow, compound bow, or other device that is capable of providing a force to the rear end of the projectile. The resulting projectile is more accurate over longer distances than traditional elongate projectiles (i.e., arrows and elongate projectiles) and is safer and quieter than conventional firearms. In addition, aspects of the projectile may be used as a stand-alone slug to be fired from an air-gun. For example, in one aspect of the technology, the butt may be used by itself as a bullet or slug in an air gun.
The projectile disclosed herein may be used in connection with an air gun. An air gun is any variety of projectile weapon that propels projectiles by means of compressed air or other gas, in contrast to firearms which use a propellant charge. Air guns are used for hunting, pest control, recreational shooting (commonly known as plinking), and competitive sports, such as the Olympic 10 m Air Rifle and 10 m Air Pistol events. In one aspect of the technology, the elongate projectile is used in connection with an air gun having a rifled bore. Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its longitudinal axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy. Rifling is often described by its twist rate, which indicates the distance the rifling takes to complete one full revolution, such as a one inch turn in ten inches (1:10 inches), or a 1 millimeter turn in 254 mm (1:254 mm). A shorter distance indicates a “faster” twist, meaning that for a given velocity the projectile will be rotating at a higher spin rate. The combination of length, weight and shape of a projectile determines the twist rate needed to stabilize it—barrels intended for short, large-diameter projectiles like spherical lead balls require a very low twist rate, such as 1 turn in 48 inches (122 cm). Barrels intended for long, small-diameter bullets, such as the ultra-low-drag, 80-grain 0.223 inch bullets (5.2 g, 5.56 mm), use twist rates of 1 turn in 8 inches (20 cm) or faster.
In some cases, rifling will have twist rates that increase down the length of the barrel, called a gain twist or progressive twist. Long projectiles, such as the elongate projectiles described herein, are thought to require high twist rates and are recommended to be fired from a smoothbore barrel. Aspects of the technology described herein cure that deficiency.
Projectile shafts, including arrows, have various sizes and fletchings or vanes of different designs. These vanes are for the purpose of better stabilization to start the arrow or elongate projectile shaft spinning. Spinning the arrow shaft is important for shaft stabilization for a number of reasons. The present technology introduces additional elements for shaft stabilization. When a standard arrow shaft is released from a bow, the arrow shaft bends around the bow staff. This is due to the arrow being forced from a standstill to full speed very quickly. This bending back and forth creates drag and decreases arrow speed. The presence of vanes and fletchings, while intended to assist in shaft spinning, also creates drag and decreases arrow speed. While shooting an arrow or an elongate projectile with fletchings or vanes in an environment with cross-winds, accuracy of the projectile is severely hampered. This is not to say that fletchings may not be used in the current invention. Rather, in certain aspects, fletchings are not used.
With specific reference now to the figures,
In one aspect of the technology, the tip 20 is removably secured to the shaft 10 so that a variety of different tips may be used on the same shaft 10. For example, the tip 20 may be replaced with a broad-head tip for hunting purposes, flat faced tips for target practice, or other tips used for other purposes. The tip 20 may be threaded onto the shaft 10, press-fit, or permanently secured by glue or some other method known in the art. In one aspect of the technology, the tip 20 is made of a dense, heavy material such as brass. The tip 20 is designed to be heavier than the remainder of the shaft 10, the stabilizer 50, and the butt 30. In this manner, the center of gravity of the elongate projectile 5 is balanced forward of the center 11 of the elongate projectile 5 which results in increased stabilization of the projectile 5 during travel through the air. While reference is made to a machined tip, it is understood that the tip 20 may be cast, molded or manufactured in a number of methods known in the art.
In one aspect of the technology, the butt 30 comprises a rigid cylinder having an annular groove (or channel) 31 disposed near the front end of the cylinder and circumscribing the cylinder. The semi-rigid cylinder has an outer diameter that is sized slightly smaller than the inner diameter of the bore of a rifle. In one aspect, the rear end of the butt 30 is tapered to assist in the placement of the projectile 5 into the bore of the rifle. The annular groove 31 is sized to receive one or more resilient O-rings 60 therein with the O-rings 60 circumscribing the annular groove 31. When placed within the annular groove 31, the outer diameter of the O-ring 60 is sized slightly larger than the inner diameter of the rifle bore. In this manner, the O-ring 60 acts to seal the rifle bore to enable pressurized air from an air rifle to deliver a propulsive force to the elongate projectile 5. The O-ring 60 also engages the riflings within the bore. As the elongate projectile 5 is propelled down the bore of the rifle, the riflings cause the elongate projectile 5 to rotate within the shaft 10. The spinning or rotation of the elongate projectile 5 within the bore increases the stabilization of the elongate projectile 5 while in flight. The lack of fletchings or vanes that are traditionally used to achieve spinning, results in a more stable flight path in any type of cross-wind. In other words, the flight path of arrows or elongate projectiles that have traditionally relied on fletchings or vanes to spin while in flight are negatively affected by a cross wind catching on the fletchings or vanes. The present technology eliminates that concern allowing the projectile 5 to fly straighter and longer distances.
With reference to
In accordance with one aspect of the technology, the O-ring is made of a resilient material such as rubber, nitrile, or polymeric materials. The butt 30 is made from an acetal resin such as Delrin® though it may be made from any suitable material, including, but without limitation, polymers, plastics, alloys and the like. The butt 30 may be molded, extruded, machined, or formed by any suitable method known in the art. The annular groove 31 is placed in the forward half of the cylindrical butt 30. The side surfaces 37 of the butt 30 act as a bearing surface to facilitate travel down the bore of the rifle as the elongate projectile 5.
In accordance with one aspect of the technology, the front face 34 of the butt 30 is substantially perpendicular to a longitudinal axis of the elongate projectile shaft 10. Drag (sometimes called air resistance or air friction) refers to the force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or a fluid and a solid surface. In the instant application, the interaction between the air and the elongate projectile 5 as the elongate projectile 5 moves in its flight path and the front face 34 of the butt 30 creates drag or frictional forces that act about the outer edge 35 of the front face 34 of the butt 30. While the drag has the negative effect of reducing the speed of the elongate projectile 5, the frictional forces are distributed evenly about the outer edge 35 of the front face 34 and act to stabilize the flight path of the elongate projectile 5.
In accordance with one aspect of the technology, the front face 34 of the butt 30 may be tapered. For example, the front face 34 may be linearly tapered outward at a forty-five degree angle. The tapering of the front face 34 decreases the drag on the butt 30 thereby increasing the speed of the elongate projectile 5, but decreasing the stabilization of the elongate projectile 5 while in flight. While a forty-five degree angle is specifically referenced, the angle of the taper may vary as suits a particular application, particularly with respect to the balancing between increased stability versus increased drag. For example, the front face 34 may vary from ninety degrees (not tapered) to twenty-five degrees (significantly tapered) with a preferred tapering of forty-five degrees. In another aspect, the front face 34 may taper outwardly in a non-linear fashion forming a curved outer surface. The front face 34 may also be linearly tapered inward (or non-linearly, i.e., concave) to increase the amount of drag on the elongate projectile 5 while in flight. The increase in drag increases the stability of the flight path of the elongate projectile 5 at the expense of reduced speed of the projectile 5. The rear end of the butt 30 has a slight taper to facilitate placement of the butt 30 within the bore of a rifle. The inner diameter of the butt 30 is sized to receive an end of the shaft 10 therein. The butt 30 is secured to the shaft 10 permanently (e.g., glued, fused, etc.) or can be removably secured to replace the butt 30 if it becomes worn over time or if the user wishes to use the elongate projectile 5 in a different application (e.g., as a nocked arrow). In accordance with one aspect, the butt 30 is formed from the same material as the shaft 10 and is integrally formed with the shaft 10 rather than being separately manufactured and later coupled to the shaft 10.
A stabilizer 50 is disposed along the shaft 10 of the elongate projectile 5. In one aspect of the technology, the stabilizer 50 is cylindrically shaped with an annular groove 51 disposed therein. The annular groove 51 functions similar to the groove 31 located within the butt 30. That is, it houses an O-ring intended to engage with the riflings of the bore of a rifle. The engagement of the O-rings with the riflings causes the shaft 10 to rotate or spin within the bore. The resulting spinning action increases the elongate projectile 5 stability during flight. Side surfaces 52 of the stabilizer 50 act as bearing surfaces to facilitate travel of the shaft 10 down the bore of the rifle and create the ultimate flight path of the elongate projectile 5. In one aspect of the technology, the stabilizer 50 is spaced a distance of at least five times the diameter of the bore from the butt 30. In other words, if the bore of a rifle intended to propel the elongate projectile 5 has an inner diameter of 0.50 inches, the distance between the front face 34 of the butt 30 and the rear face 53 of the stabilizer 50 is 2.5 inches. The stabilizer 50 may be placed a distance beyond five times the diameter of the bore away from the butt 30 depending on the size of the bore and the relative weight of the elongate projectile 5. For elongate projectiles 5 that are relatively heavy, with a tip 20 that is light (based on a desired use of the tip 20) the stabilizer 50 may be placed nearer the center 11 of the shaft 10 in an effort to balance the elongate projectile 5 to maximize projectile stability. In one aspect of the technology, the annular groove 51 is disposed in the front half of the stabilizer 50. However, in other aspects, the annular groove 51 is disposed in the middle of the stabilizer 50 or towards the rear end of the stabilizer 50.
As with the butt 30, the front face 54 of the stabilizer 50 is substantially perpendicular to a longitudinal axis of the shaft 10 of elongate projectile 5. Similar to the drag created on the front face 34 of the butt 30, as the elongate projectile 5 travels through the air, frictional forces from the air act equally about the outer edge 55 of the front face 54 creating a stabilizing force on the elongate projectile 5 in flight. In one aspect of the technology, the front face 54 may be tapered outward to reduce the drag about the front face 54. In another aspect, the front face 54 may be tapered inward or concave to increase the drag on the front face 54.
While specific reference is made herein to a cylindrical front face 54, it is understood that the front face 54 of the stabilizer 50 (as well as the front face 34 of the butt 30) may have designs placed thereon to optimize the ratio between drag and projectile speed. For example, the front face 54, may not be perfectly planar. Rather, it may have protrusions, indentations, or other designs associated therewith. In addition, other modifications may be made to optimize projectile spin as suits a particular application. For example, one or both of the tip 20 and the stabilizer 50 may be equipped with grooves disposed at an angle to the longitudinal axis of the elongate projectile 5 to induce spinning when the elongate projectile 5 is launched from a smooth bore barrel, cross-bow, or other apparatus that lacks riflings. In certain aspects of the technology, the butt 30 is configured to act as the stabilizer 50. This may be in addition to a stabilizer 50 disposed elsewhere about the shaft 10, and may include fletchings that act as conventional stabilizers. It may also include aspects without any additional stabilization means.
With reference now generally to
In accordance with one aspect of the technology, the annular groove 110 comprises a tapered front section 111 and a tapered rear section 112. While a tapered front section 111 and rear section 112 are both shown, it is understood that the butt 110 could comprise a tapered front section 111 or a tapered rear section 112 or both as suits a particular purpose. In accordance with one aspect where an O-ring (or other resilient member) is disposed within the annular groove 110, when the projectile (either in connection with an arrow or as a stand-alone slug) is propagated from an air-rifle, the air pressure from the air-rifle used to propel the projectile out of the air gun drives the O-ring forward over the tapered front section 111. Because the tapered front section 111 has an increasing outer diameter, as the O-ring is driven forward over the tapered front section 111, the O-ring expands. As the O-ring expands its outer diameter is increased and it engages the side walls of the internal bore of the air rifle. As the O-ring engages the internal bore of the air rifle, frictional forces created by the engagement drive the O-ring towards a rear section of the annular groove 110. It is believed that the pressure gradient from the pressurized air acting on the O-ring decreases as the projectile travels down the bore of the air rifle. Accordingly, it is believed that during its initial movement down the bore of the air rifle, the O-ring is driven forward and, due to its expansion over the front tapered section 111, engages the internal bore of the air gun. However, as the pressure gradient decreases during the initial movement down the bore, the frictional forces acting on the O-ring, driving the O-ring backward will be greater than the air pressure driving O-ring forward. As that happens, the O-ring will be driven backward and return to its biased (or non-expanded) state within the non-tapered portion of the annular groove 110. In one aspect, a frictional force continues to act on the O-ring as the projectile travels down the bore of the air rifle causing the O-ring to continue to move backward and over the rear tapered section 112. While in its biased state, the O-ring engages the sidewall of the internal bore, however, in one aspect, the engagement is not enough to create satisfactory “spinning” of the projectile. As the O-ring is propelled or driven backward over the rear tapered section 112, it expands and engages the internal bore to a greater degree creating a greater seal or greater engagement resulting in increased “spinning” of the projectile. It is believed that the degree to which the O-ring is advanced over the front tapered section 111 and its movement rearward as the projectile travels down the bore of the air gun is a function primarily of the sizing of the O-ring with respect to the internal bore of the air gun and the diameter of the annular groove 110, and the amount of pressure acting on the projectile from pressurized air. The system seeks equilibrium between the air pressure driving the O-ring forward, the frictional forces resulting from engagement of the O-ring with the internal bore of the air gun, and the O-ring's tendency to return to its biased state in the non-tapered section of the annular groove 110. Advantageously, the present technology takes advantage of all three forces to optimize engagement of the O-ring with the riflings of the bore of the air gun.
While reference is made to a single O-ring on butt 100, it is understood that one or more O-rings (or other resilient members) may be disposed in a single annular groove 110. In one aspect, it is believed that as a first O-ring is driven backward over the rear tapered section 112, a second O-ring, abutted against the first O-ring, is also driven backward pushing the first O-ring further over the rear tapered section 112 resulting in an increased engagement against the internal bore of the air gun. The foregoing examples include use of the butt 100 on an arrow as shown in
While the foregoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.
This application claims priority to U.S. Provisional Patent Application No. 62/018,165 filed on Jun. 27, 2014 entitled “Improved Air Gun Dart” and is a continuation-in-part of U.S. patent application Ser. No. 14/751,895 filed on Jun. 26, 2015 both of which are incorporated herein by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 62018165 | Jun 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14751895 | Jun 2015 | US |
| Child | 15094629 | US |
