Patent Grant
7883435
This invention is directed generally to broadheads, and more particularly to broadheads capable of being tuned.
Modern broadheads are tips attachable to a distal end of an arrow shaft and include one or more blades having cutting arrises. The blades extend outwardly from a generally cylindrical broadhead body. The blades typically extend from the broadhead such that the cutting arris of each blade are at an acute angle relative to a longitudinal axis of the broadhead body and extend from a distal point at an intersection at an outer surface of the broadhead body to near the tip at an outer surface of the broadhead body to a proximal point radially outward of the outer surface of the broadhead body. In this position, the blades are capable of cutting flesh as the broadhead passes through an animal.
Modern compound bows can propel arrows at speeds of greater than 300 feet per second. Accurate arrow flight at such speeds is typically only accomplished when all components of the bow and arrow system are tuned properly. For instance, cam timing, cam and wheel alignment, rest position, arrow nock position, fletching clearance, arrow weight consistency, arrow spline consistency, broadhead configuration, and broadhead alignment are all factors that can each greatly affect accuracy. Broadheads have always proved challenging to tune. A longitudinal axis of a broadhead must be aligned with a longitudinal axis of the arrowshaft. Otherwise, the blades can act as airfoils and cause the arrows to plane, which severely affects accuracy.
Broadheads often need to be aligned relative to the arrowshaft to insure adequate clearance of the broadhead past the arrow shelf of a bow. In addition, the blades of a broadhead often need to be aligned with the fletching of an arrow and relative to the bow riser. In particular, in connection with broadheads having two bladed designs, it is often desirable to align the blades of the broadhead such that the blades are generally aligned with the riser of the bow. Sometimes, the blades may need to be aligned differently to create the most consistent arrow flight, which is often determined through repeated use.
Broadheads are commonly attached to arrows through use of a threaded insert glued into the end of a hollow aluminum or carbon arrow. Broadheads typically include a threaded post sized to be inserted into the insert and tightened down with a broadhead wrench. Once the broadhead is tightened into position, the alignment of the blades of the broadhead is examined. The alignment of the blades may be changed in aluminum arrows by heating the insert to loosen or melt the glue so that the insert may be rotated within the aluminum shaft. Carbon arrows may not be heated because the heat can easily damage the carbon fibers. While heating the arrows enables the inserts to be rotatable within the arrow shaft, repeated heating typically reduces the strength of the glues and often creates poor connections between the inserts and the arrows.
This invention relates to a tunable broadhead attachable to an arrow shaft. The broadhead may be secured to an arrow shaft such that the broadhead may be adjustable about a longitudinal axis relative to the arrow shaft. The broadhead may be rotatable about the longitudinal axis such that blades extending outwardly may be moved into different positions relative to the arrow shaft to tune arrow flight. A releasable locking device may be affixed to prevent the broadhead from rotating relative to the arrow shaft to keep the blades in a desired orientation. Configuring the broadhead in this manner enables alignment of the blades to be adjustable relative to the arrow shaft. Thus, the alignment of the blades extending from the broadhead may be adjusted to increase consistency of arrow flight from a bow.
The tunable broadhead includes a generally elongated broadhead body having a proximal portion configured to be attached to a shaft and a tip at a distal portion that is configured to facilitate penetration of the tip into an object. A plurality of blades may be separated circumferentially from each other about a longitudinal axis of the generally elongated broadhead body and may extend outwardly from the generally elongated broadhead body. The generally elongated broadhead body may include a bore that extends from a proximal end of the generally elongated broadhead body into the generally elongated broadhead body and may be aligned with the longitudinal axis. An extension member may have a distal portion positioned within the bore and a proximal portion extending along the longitudinal axis away from the generally elongated broadhead body, wherein the extension member may be rotatable within the bore. The distal portion of the extension member may be threaded, and the bore may be threaded such that the extension member may be releasably attached to the generally elongated broadhead body. The proximal portion of the extension member may also be threaded for attachment to an arrow shaft. The threads on the distal portion may be sized with a different pitch than the threads on the proximal portion. Such a configuration enables the orientation of the blades to be changed.
A releasable locking device may be included and may be configured to releasably affix the extension member relative to the generally elongated broadhead body to prevent the generally elongated broadhead body from being rotated relative to the extension member. In one embodiment, the releasable locking device may include a threaded set screw threadably attached to a threaded orifice in the generally elongated broadhead body. The threaded orifice may extend radially inward through the generally elongated broadhead body. The threaded orifice may be positioned aft of the plurality of blades. In other embodiments, the releasable locking device may be a chemical applied to the distal portion of the extension member, a nylon threadlocker material, or other appropriate device.
An advantage of this invention is that the blades may be oriented in any position independent of the orientation of the insert within an end of the arrow shaft. Thus, the blades may be oriented in any positioned about a longitudinal axis of the arrow shaft to improve clearance and accuracy. For instance, the blades of three blade embodiments may be aligned with the fletching on the arrow. In other embodiments, such as two blade embodiments, the blades may be aligned to reduce planing upon the broadhead leaving the bow during the initial moments of the shot.
These and other embodiments are described in more detail below.
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.
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In one embodiment, the blades 14 may be removably attached to the elongated broadhead body 20. The blades 14, tip 24 and elongated broadhead body 20 may be configured and attached to the elongated broadhead body 20 as set forth in U.S. Pat. No. 5,482,294, which is incorporated by reference herein in its entirety. In particular, the blades 14 may include a flange 32 that facilitate removable attachment of the blades 14 within a central chamber 34 of the elongated broadhead body 20. The blades 14 may extend outwardly through a plurality of slots 38 positioned in the elongated broadhead body 20. The tip 24 may include a distally extending shaft 36 configured to be releasably attached within the central chamber 34 to force the flange 32 of the blades 14 radially outward against the wall forming the central chamber 34. The tip 24 may be threadably attached within the central chamber 34. The tip 34 may also prevent the blades 14 from being removed through a distal opening 40 in the central chamber 34.
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The threads on the distal portion 52 may be sized with a different pitch than the threads on the proximal portion 22. Such a configuration enables the orientation of the blades to be changed. Otherwise, if the thread pitch of the distal portion 52 were equivalent to the thread pitch of the proximal portion 22, then orientation of the blades would not change even though the extension member 46 had been moved. In particular, the distal portion 52 may be rotated to move the distal portion 52. Because the threads of the distal portion 52 are pitched differently than the proximal portion 22, the broadhead body 20 may rotate a different amount before contacting the insert 48, thereby creating a different alignment for the blades 14 relative to the arrow 12. In one embodiment, the threads on the distal portion 52 may be about 48 threads per inch with a size 4 (4-48), and the threads on the proximal portion 22 may be about 32 threads per inch with a size 8 (8-32), which create approximately a 3 to 1 ratio. When the distal portion 52 is rotated about one full rotation, the orientation of the blades 14 may be changed about 120 degrees. The configuration of the extension member 46 is not limited to this particular configuration but may also have alternative configurations as well.
The releasable locking device 16 may be configured to releasably affix the extension member 46 relative to the generally elongated broadhead body 20 to prevent the generally elongated broadhead body 20 from being rotated relative to the extension member 46 once positioned as desired. When unlocked, the releasable locking device 16 permits the blades 14 of the broadhead 10 to be aligned as desired even after the broadhead 10 has been attached to the arrow shaft 12 by attaching the proximal portion 54 of the extension member 46 in the insert 48 of the arrow shaft 12. The releasable locking device 16 may be formed from any device capable of releasably securing the generally elongated broadhead body 20 to the extension member 46. In one embodiment, as shown in
In another embodiment, the releasably locking device 16 may be a chemical capable of increasing friction between the threads of the distal portion 52 and the bore 42. The chemical may be any appropriate chemical capable of increasing the resistance to the extension member 46 rotating relative to the bore 42. The releasably locking device 16 may also be a nylon threadlocker material or another appropriate material capable of increasing the resistance to the extension member 46 rotating relative to the bore 42.
During use, the broadhead 10 may be fully assembled with blades 14 intact. In embodiments in which the blades 14 are separate components, the blades 14 may be attached to the broadhead 10 and secured thereto. If the releasable locking device 16 is not already tightened, it should be tightened to securely engage the extension member 46. The broadhead 10 may then be attached to the arrow shaft 12. In one embodiment, the proximal portion 54 that extends uncovered from the generally elongated broadhead body 20 may be inserted into the insert 48 and rotated to mesh the threads of the proximal portion 54 to the threads of the insert 48. The generally elongated broadhead body 20 may be rotated until the generally elongated broadhead body 20 is securely attached to the arrow shaft 12.
The alignment of the blades 14 with the arrow 12 may be checked. If the alignment of the blades 14 is determined to be misaligned, the broadhead 10 may be removed from the insert 48. The releasable locking device 16 may then be released, thereby permitting the broadhead body 20 to rotate relative to the extension member 46. By rotating the generally elongated broadhead body 20, the orientation of the blades 12 collectively may be changed relative to the arrow shaft 12. Once the generally elongated broadhead body 20 has been properly aligned, the releasable locking device 16 may be moved to securely engage the extension member 46. In one embodiment, a wrench, such as an alien wrench or other appropriate wrench, may be used to rotate the releasable locking device 16, such as the set screw 60, to tighten the releasable locking device 16 against the extension member 46. The broadhead body 20 may then be reattached to the arrow 12. The broadhead body 20 may be tightened against the arrow 12 and when the broadhead body 20 is tightened against the arrow 12, the orientation of the blades 14 relative to the arrow 12 is different. Thus, the tunable broadhead 10 is configured such that the orientation of the blades 14 is adjustable. In particular, the blades 12 may be aligned with the fletching of the arrow shaft 12, aligned relative to the nock and thereby aligned relative to the bow from which the arrow shaft 12 will be shot, or aligned in another appropriate alignment.
The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4781386 | Armitage | Nov 1988 | A |
| 5482294 | Sullivan et al. | Jan 1996 | A |
| 5494298 | Maleski | Feb 1996 | A |
| 7232390 | Mizek et al. | Jun 2007 | B2 |
| 7338397 | Mizek et al. | Mar 2008 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20090124439 A1 | May 2009 | US |
