Patent Grant
9297620
The present invention relates generally to archery. The present invention is more particularly, though not exclusively, useful as an improved archery arrow having improved weight distribution and aerodynamics.
Archery arrows have been in use for centuries. Over this time period, significant improvements have been made in the design of the arrows. For instance, the materials used for arrows have evolved from ancient arrows made of wood to modern arrows fabricated using lightweight high strength carbon fiber composites. Also, the fletching, or finning, has evolved from a standard X-shape feather to an aerodynamic three-tab design which minimizes contact with the bow and improves accuracy. Improvements have also been made to the arrow head to improve the aerodynamics and to the nock to decrease weight.
With the advancements in technology, the performance of an arrow can be tuned to fit an archer's preferences. Altering the physical properties of an arrow alters the flight characteristics. Traditionally, archers chose an arrow shaft with a defined static spine, which is the stiffness of the arrow and its resistance to bending. Based on their chosen arrow shaft and corresponding static spine, they then add tips, fletching, and knocks to tune the dynamic spine, which is the deflection of the arrow when fired from a bow. Thus, the physical properties of the arrow shaft, including the overall weight and the center of gravity of the arrow, affects the arrow performance.
A recent trend in the arrow industry is to provide an arrow having a wider diameter shaft. Typical arrows have had a standard external shaft diameter of 0.295 inches which has provided for a reasonably rigid arrow made from today's materials. However, a thicker arrow having an external shaft diameter of 0.380 has been developed for certain archery applications.
However, with the wider diameter of these thicker arrows comes an increase in weight and aerodynamic drag caused by the larger cross-section. In order to minimize the effects of the larger diameter on the arrow performance, the industry has taken steps to minimize weight of the arrow. For instance, some manufacturers have provided adaptors which allow the archer to use standard diameter nocks. However, in order to use the smaller diameter nocks, a transitional sleeve, or taper, must be inserted between the shaft and the nock. Unfortunately, this added insert provides excess weight at the fletching end of the arrow. This is particularly so when using carbon-fiber arrows where the weight of the arrow is small compared to the weight of the tip and nock.
In light of the above, it would be advantageous to provide an arrow having increased strength and decreased drag which is also lightweight. It would also be advantageous to provide an arrow capable of using standard nocks without having to add weight-increasing adapters and inserts. It would further be advantageous to provide an arrow having multiple interior diameters, multiple exterior diameters, and multiple wall thicknesses to alter the weight distribution of an arrow shaft and control the center of gravity. It would further be advantageous to provide an arrow having multiple interior diameters, multiple exterior diameters, and multiple wall thicknesses to vary the static spine of the arrow shaft. It would further be advantageous to provide an arrow having a larger knock end to better absorb the forces of a bow string when fired. It would further be advantageous to provide an arrow having a smaller forward section for better aerodynamics and deeper penetration.
The present invention includes a cylindrical carbon fiber arrow shaft formed with an increased external diameter of 0.380 inches. This arrow shaft is formed with an axial bore which has a first internal diameter throughout a substantial portion of the shaft length, and a second, smaller, internal diameter throughout the fletching end of the arrow. The second internal diameter corresponds to the internal diameter of standard arrows having external diameters of 0.295 inches. Using this standard internal diameter at the fletching-end of the arrow, standard nocks may be used without the need for any spacer or insert, thereby decreasing fletching-end weight significantly and providing for the proper and more desired location of the center of gravity forward on the arrow.
The dual interior-diameter design of the arrow of the present invention is accomplished using a cylindrical mandrel having two external diameters. The first mandrel diameter corresponds to the portion of the arrow shaft having the external diameter of 0.380 inches, and the second mandrel diameter corresponds to the standard nock dimensions.
The carbon fiber shaft is formed on the mandrel. With the aid of releasing agents, the mandrel is removed leaving a tubular shaft having a decreased internal diameter at the fletching end of the arrow. A taper is formed at the end of the arrow to provide for a smooth transition between the arrow shaft and the smaller-diameter nock. A nock is then inserted, the fletching is applied, and a tip is installed to provide a high strength, low eight archery arrow having less mass than comparable arrows.
In an alternative embodiment, the present invention includes a cylindrical carbon fiber arrow shaft formed with a uniform exterior surface having a single exterior diameter and a non-uniform axial bore having multiple interior diameters. In a particular embodiment, the non-uniform axial bore has a first internal diameter throughout the forward section of the shaft and a second internal diameter throughout the remaining tail section of the shaft length. Alternatively, the non-uniform axial bore is formed with a combination of cylindrical and tapered sections, with each section having a different diameter.
In an alternative embodiment, the present invention includes a cylindrical carbon fiber arrow shaft formed with a non-uniform exterior surface having multiple diameters and a non-uniform axial bore having multiple diameters. In a particular embodiment, the cylindrical carbon fiber arrow shaft tapers from a tail section to a forward section, wherein the tail section has a larger diameter than the forward section. By having a larger exterior diameter at the tail end, the tail end of the arrow shaft is better able to absorb and dampen the impact from the bow string when the arrow is fired. The smaller diameter forward section provides less aerodynamic drag and better penetration as compared to an arrow shaft with a forward section having a larger diameter.
The arrow shaft is formed with a non-uniform axial bore having multiple diameters. The axial bore may have stepping internal diameters, such that a first diameter terminates into a smaller second diameter. Alternatively, the axial bore may have a tapering section between each major diameter such that a first diameter tapers into a second diameter.
The nonuniform axial bores of the alternative embodiments allow the precise control of the center of gravity of the arrow shaft. By modifying each section of the axial bore, particularly the diameters and the length of each portion, the location of the center of gravity may be shifted along the length of the arrow shaft. The use of multiple internal diameters also affects the stiffness of the arrow. By having an internal axial bore with different internal diameters, the stiffness of the arrow along the shaft length is non-uniform thereby affecting the static and dynamic spine of the arrow. The option to vary the interior and exterior diameters allows a user more options to properly tune the arrow to their specifications.
The carbon fiber arrow shafts are formed on a mandrel having multiple diameters. In certain embodiments, the mandrel may be made of multiple pieces mated together to form a single piece. By utilizing a two piece mandrel, an arrow shaft having an axial bore with a smaller internal diameter preceded by a larger diameter and followed by a larger diameter is possible. With the aid of releasing agents, the mandrel is removed leaving a tubular shaft having a non-uniform internal axial bore having multiple diameters. A nock is then inserted, the fletching is applied, and a tip is installed to provide a high strength, low weight archery arrow having less mass than comparable arrows.
The objects, features, and advantages of the method according to the invention will be more clearly perceived from the following detailed description, when read in conjunction with the accompanying drawing, in which:
Referring now to
The nock can also affect the position of the center of gravity. For instance, in arrows having very low weights, the addition of the nock at the end of the arrow can bring the center of gravity away from the tip, sometimes resulting in a less-than-optimum placement.
Referring now to
Arrow 100 includes a tip 106 which is typically a weighty metallic material, such as steel, and can be formed with different shapes for specific uses, such as target shooting, hunting, etc. Retching 108 is attached to the exterior of body 102 as is known in the art, and nock 20 is inserted into the fletching end of the shaft body 102.
Arrow shaft 102 is formed with an axial bore (shown in
Arrow 100 is shown having an exemplary center-of-gravity 114 which as is known in the art, may be adjusted along the length of the shaft 102 by adjusting the weights of the tip 106, fletching 108 and nock 20. Also, the position of the center of gravity may be affected by the shortening, or cutting, of the length of the arrow.
A tapered section 110 of body 102 transitions the arrow from the larger diameter of 0.380 inches, to a smaller diameter, such as 0.295 inches to correspond to the diameter of the nock 20. The length of the taper and the angle of the taper can vary depending on the manufacturing of the arrow 100 without departing from the spirit of the present invention.
An example of a typical manufacturing method is depicted in
Tapered section 110 is formed on the fletching end of body 102 by removing a portion 120 of the carbon fiber materials as shown by dashed lines. The removal of the material of body 102 may be accomplished using a variety of techniques, such as by grinding as is known in the art.
The arrow of the present invention exhibits improved aerodynamics, lower mass, and has a better weight distribution than other large diameter arrows which require the use of heavy transition pieces, or super-sized mocks. The use of the standard nock without any additional hardware provides the arrow of the present invention with a significant advantage over other arrows.
Referring now to
The tail bore 210 is sized to closely receive an insert 205 of nock 204 and the tip bore 220 is sized to closely receive an insert 207 of tip 206. The outside diameter of insert 205 of nock 204 creates an interference fit with the tail bore 210 to provide a secure fit for nock 204 and may be affixed with an adhesive or other attachment means known in the art such as a twist lock or threads. Tip 206 may be attached to the arrow shaft 202 in substantially similar manner as insert 205. The exterior diameter of the arrow shaft 202 does not require a tapered exterior section as the exterior diameter of the arrow shaft 202 matches the exterior diameter of tip 206 and nock 204.
In an exemplary example, the external diameter 203 of arrow 200 is approximately between 0.210 and 0.245. Due to the small external diameter 203, the forward bore 218 diameter 216 may be too small to accommodate a tip or tip insert currently available in the marketplace. To use the tips or tip inserts currently available in the marketplace, the tip bore 220 may be sized larger than forward bore 218, allowing the use the appropriate tip 206. As a result of using a smaller external diameter as compared to arrows with standard external diameters of 0.295 inch, arrow 200 is lighter and the use of smaller available tips and nocks without the need for any spacer or insert further decreases overall weight significantly. This provides for the proper and more desired location of the center of gravity forward on the arrow 200. It is also contemplated that tips and tip inserts made specifically to fit the forward bore 218 diameter 216 may be used, thereby removing the need of the tip bore 220.
As depicted, the arrow 200 has tail bore 210, forward bore 218 and tip bore 220. The arrow shaft 202 has multiple wall thicknesses as a result of the tail bore 210, forward bore 218 and tip bore 220. Due to the varying thicknesses of the arrow shaft 202 walls, the weight distribution of the arrow shaft is unequal. The smaller forward bore 218 compared with the tail bore 210 places more material and thus weight towards the front of the arrow shaft 202. Typically, an arrow shaft having a uniform interior and exterior diameter constructed of a uniform material the center of gravity of the arrow shaft is located at the midpoint of the arrow shaft. However, with the multiple interior diameters of arrow shaft 202 the center of gravity 201 may be located off-center towards the tip 206. By modifying the length and diameter of the tail bore 210, forward bore 218 and tip bore 220 the center of gravity 201 may be shifted along the length of the arrow shaft 202. It is appreciated that the number of bores with different diameters could be varied as well without departing from the spirit and scope of the present invention. After taking into account the center of gravity of the arrow shaft 202, the tip 206, fletching 208, and knock 204 is applied to adjust the center of gravity 201 of the arrow 200. As a result, a greater degree of adjustability and tuning of the center of gravity 204 of the arrow 200 may be achieved.
The construction of the arrow 200 having multiple interior diameters and multiple exterior diameters also affect the stiffness of the arrow 200. The stiffness of an arrow is determined by the material of the arrow, the interior and exterior diameters of the shaft, the thickness of the shaft wall, the interior and exterior wall geometry, and the length of the arrow shaft. Although the arrow shaft 202 has an overall stiffness, the stiffness of the arrow shaft 202 varies along the length due to the multiple diameters and wall thicknesses.
An example of a typical manufacturing method for arrow 200 is depicted in
The primary mandrel 230 is threadably received by the secondary mandrel 240, forming the mandrel in which the carbon fiber is wrapped to from arrow shaft 202. The use of the threaded stud 235 and bore 242 is not meant to be limiting and alternative means of fastening the primary mandrel 230 to the secondary mandrel 240 are contemplated without departing from the scope and spirit of the invention. Further, it is contemplated that arrow 200 may be formed without tip bore 220, thereby removing the need for secondary mandrel 240 or may be formed with additional bores requiring addition mandrel pieces.
After the carbon fiber has hardened and cured into arrow shaft 202, with the aid of releasing agents the primary mandrel 230 and secondary mandrel 240 are removed from the arrow shaft 202. Before removing the primary mandrel 230 and secondary mandrel 240, the mandrels are decoupled from one another. This allows the primary mandrel 230 to be removed in direction 236 and secondary mandrel 240 removed from the arrow shaft 202 in direction 244, opposite of direction 236. The two piece mandrel enables the creation of an arrow shaft having multiple internal diameters in which a single mandrel would not be able to. By utilizing a two piece mandrel, an arrow shaft having an axial bore with a smaller internal diameter preceded by a larger diameter and followed by a larger diameter similar to arrow shaft 202 is possible.
As a single piece mandrel, the removal of a mandrel from an arrow shaft would not be possible as the larger diameter portion of the mandrel would not be able to pass through the smaller diameter portion of the arrow shaft. However, by creating the mandrel in multiple pieces, the mandrel can be decoupled and pulled in opposite directions 236 and 234 to remove the mandrel from the arrow shaft. It is contemplated that the mandrel may be sized differently and be composed of multiple pieces to create various axial bores for arrow shafts without departing from the spirit and scope of the invention.
Referring now to
Before applying the tip 206, fletching 208, and nock 204 to adjust the center of gravity 201 of the arrow 250 the center of gravity of the arrow shaft 202 needs to be accounted for. The length, diameter, and wall thickness of the arrow shaft 202 may be modified to adjust the center of gravity of the arrow shaft 202 along the length by adjusting the internal bores of the arrow shaft. As a result, a greater degree of adjustability and tuning of the center of gravity 201 of the arrow 200 may be achieved. Additionally, although there is an overall stiffness to the arrow shaft 202, the stiffness of varies along the length of the arrow shaft 202 due to the construction of the arrow shaft 202 having multiple diameters and wall thicknesses.
Now referring to
After the carbon fiber has hardened and cured into arrow shaft 209, with the aid of releasing agents the tail end mandrel 260 and the forward end mandrel 264 is removed from the arrow shaft 202. Before removing the mandrels, the tail end mandrel 260 and the forward end mandrel 264 are decoupled from one another and pulled apart from the arrow shaft 202 in directions 263 and 267, respectively.
Referring now to
In an exemplary example, the exterior diameter 312 is approximately between 0.210 and 0.388 inches and the exterior diameter 332 is also approximately between 0.210 inches and 0.388, with the exterior diameter 332 of forward section 330 smaller than exterior diameter 312 of the tail section 310. As a result, the forward section 330 has less surface area and the taper section 320 provides a smooth transition from the smaller forward section 330 to the larger tail section 310, creating an aerodynamic arrow body with a small coefficient of drag resulting in less friction in the air and within a target when penetrating. The larger exterior diameter 312 of the tail section 310 of arrow shaft 302 is able to absorb and dampen the vibration caused by the impact from a bowstring when the arrow 300 is fired better than a smaller diameter arrow, resulting in a more controlled flight.
As depicted, the arrow 300 is formed with the arrow shaft 302 having the tail section 310 with taper section 320 tapering to the forward section 330, resulting in a varying external diameter or multiple specific exterior diameters. Further, the arrow shaft 302 is formed with the tail bore 314 and forward bore 334, resulting in arrow 300 with multiple interior diameter such as 316 and 336. It is appreciated that the number of bores and external sections with different diameters could be varied without departing from the spirit and scope of the present invention.
As a result of the tail section 310, taper section 320, forward section 330, tail bore 314, and forward bore 334, the arrow shaft 302 has multiple wall thicknesses. Due to the varying thicknesses of the arrow shaft 302 walls, the weight distribution of the arrow shaft is unequal. Due to the smaller forward bore 334 compared with the tail bore 314, more material and thus weight is located towards the front of the arrow shaft 302. By modifying the length of the tail section 310, taper section 320, and forward section 330 in conjunction with modifying the length and diameter of tail bore 314 and forward bore 334, the center of gravity 301 may be shifted along the length of the arrow shaft 302. After taking into account the center of gravity of the arrow shaft 302, the tip 306, fletching 308, and nock 304 is applied to adjust the center of gravity 301 of the arrow 300. As a result, a greater degree of adjustability and tuning of the center of gravity 301 of the arrow 300 may be achieved.
The construction of the arrow 300 having multiple interior diameters and multiple exterior diameters also affect the stiffness of the arrow 300. The stiffness of an arrow is determined by the material of the arrow, the interior and exterior diameters of the shaft, the thickness of the shaft wall, the interior and exterior wall geometry, and the length of the arrow shaft. Although the arrow shaft 302 has an overall stiffness, the stiffness of the arrow shaft 302 varies along the length due to the multiple diameters and wall thicknesses.
An example of a typical manufacturing method for arrow 300 is depicted in
After the carbon fiber has hardened and cured into arrow shaft 302, with the aid of releasing agents the mandrel 340 is removed from the arrow shaft 302 in direction 338. It is contemplated that the use of multiple cylindrical sections having different diameters forming mandrel 340 may be used to construct an alternative non-uniform axial bore within arrow shaft 302. It is further contemplated that the mandrel 340 may constructed of multiple pieces which may be combined to create axial bores having varying diameters, shapes, and sizes.
Referring now to
An example of a typical manufacturing method for arrow 350 is depicted in
Although the present invention has been described herein with respect to preferred and alternative embodiments thereof, the forgoing descriptions are intended to be illustrative, and not restrictive. Those skilled in the art will realize that many modifications of the preferred and alternative embodiments could be made which would be operable, such as combining the various aspects of each preferred and alternative embodiments. All such modifications which are within the scope of the claims are intended to be within the scope and spirit of the present invention.
The present application is a continuation-in-part of, and claims the benefit of priority to, Utility patent application Ser. No. 13/909,888 filed Jun. 4, 2013, which is now U.S. Pat. No. 8,834,658, which is a divisional of, and claims the benefit of priority to, U.S. patent application Ser. No. 12/943,870 filed Nov. 10, 2010, which is now U.S. Pat. No. 8,496,548 issued on Jul. 30, 2013.
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| Entry |
|---|
| Tim Dehn, “Gold Tip Arrow Production Bounces Back from Involuntary Plant Closure”, Arrow Trade Magazine, United States. |
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| Number | Date | Country | |
|---|---|---|---|
| 20150133245 A1 | May 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12943870 | Nov 2010 | US |
| Child | 13909888 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13909888 | Jun 2013 | US |
| Child | 14486587 | US |
