US20090247333A1

US20090247333A1 - Arrow having an insert head assembly and fletching design

Info

Publication number: US20090247333A1
Application number: US12/058,555
Authority: US
Inventors: Walter E. Bottelsen
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-28
Filing date: 2008-03-28
Publication date: 2009-10-01

Abstract

An arrow assembly having an elongated tubular arrow shaft, with a plurality of slits extending forwardly from the rearward end of the shaft, an expandable locking insert mounted at the forward end of the arrow shaft, a arrow head having a ball-shaped tip mounted on the locking insert, a fletching mechanism having a central spine mountable inside the shaft and a plurality of vanes extending radially outwardly from the spine and through the slits in the shaft, and a nock mountable at the rearward end of the shaft. The assembly can be assembled, disassembled and repaired in the field.

Description

FIELD OF THE INVENTION

This invention relates to archery equipment and, in particular, to an arrow assembly that is easily assembled and repaired in the field, minimizes target damage, and has enhanced flight accuracy.

BACKGROUND OF THE INVENTION

Arrows for archery come in many shapes, types and sizes. A typical arrow includes an arrow shaft with a pointed arrow head mounted at the forward end of the shaft, and a nock mounted at the rearward end. Particularly when the shaft is hollow, the arrow head may be mounted to the shaft by a shaft insert, which extends into and is glued into the interior of the shaft. Near the rearward end of the shaft, there is also a fletching, which typically consists of a plurality of feathers or plastic vanes, fixed to the exterior body of the shaft.
In traditional arrows, the insert for mounting an arrow head, the nock and the fletchings are permanently affixed with adhesives to the shaft and are typically assembled by the manufacturer or proshop. When one of these components, e.g., the fletching, needs to be replaced due to damage or to accommodate for changing environmental condition, the component must be removed and a new component glued in place before the arrow can be used. Because the repair process is time consuming and typically requires specialized tools, such replacements cannot be done easily in field.

SUMMARY OF THE INVENTION

In one aspect of the present invention, there is provided an arrow assembly including a hollow shaft, an arrow head mounted to the forward end of the shaft by means of a locking insert, a fletching assembly and a nock assembly.
In one exemplary embodiment, the arrow head has an exterior tip portion and a shank portion that extends rearwardly from the tip portion. The tip portion has a bulbous or ball-shaped tip at the forward end of a supporting neck. The neck is preferably tapered or conical in shape, extending rearwardly and radially outwardly preferably to a diameter generally the same as the diameter of the arrow shaft. The shank is generally cylindrical in shape and extends rearwardly from the rearward end of the neck into the interior of the locking insert. A rearward portion of the shank is threaded for engaging the threaded interior of the locking insert.
In another aspect of the invention, there is provided an expandable locking insert for mounting the arrow head to the shaft. The locking insert has an annular flange at its forward end preferably having an outer diameter about the same as the outer diameter of the arrow shaft. A generally cylindrical insert body extends rearwardly from the flange. A rearward portion of the insert body has an inner surface that is tapered slightly radially inwardly and is threaded. The rearward portion of the insert body includes at least one lengthwise slit for enabling radial expansion of the rearward portion of the insert body against the interior surface of the arrow shaft. In an exemplary embodiment of the invention, the locking insert includes a locking set screw that can be threaded into the rearward portion of the insert body by, for example an Allen wrench, to expand the rearward portion of the insert body against the interior wall of the arrow shaft.
In another aspect of the present invention, there is a fletching assembly that includes a plurality of lengthwise slits, preferably three or four, at the rearward end of the arrow shaft and a fletching mounted in association with the slits. The fletching has a center spine and a number of vanes equal in number to the number of slits in the arrow shaft. In one exemplary embodiment, the fletching has four vanes, each having a forward tapered end, and a rounded rearward end. The vanes are generally identical and integrally connected along this spine. Adjacent vanes are generally at right angles to each other
In one exemplary embodiment, the slits in the shaft body are parallel to each other and to the longitudinal axis of the shaft body. In another embodiment, the slits extend slightly to helically about the longitudinal axis of the shaft body.
In another aspect of the invention, there is provided a nock assembly particularly useful with the fletching assembly. The nock assembly comprises a nock having a generally cylindrical insert portion that extends into the rearward end of the arrow shaft and an exterior portion that comprises a slot for receiving a bow string. The insert portion of the nock preferably has slits at its forward end arranged to receive the rearward edges of the fletching and to be compressed radially inwardly to facilitate insertion into the shaft. The nock assembly also includes a retaining sleeve disposed about the outer circumference of the arrow shaft. The retaining sleeve is movable between a release position spaced apart from the rearward end of the shaft and a retaining position at the end of the shaft. When the insert portion of the nock is inserted into the rearward end of the shaft, the retaining sleeve is moved from its release position to its retaining position which compresses the shaft against the insert portion of the nock to secure the nock to the shaft.
In another aspect of the invention, the arrow shaft is tubular and has a stiffness along the shaft that is non-uniform, e.g., is greater along one side of the shaft than other portions of the shaft. The stiffer side is determined by measurement, and the nock is mounted so that the slot in the nock is at right angles to the side of the arrow shaft having the greater stiffness. A mark or other indicator is applied to the exterior of the shaft so that the arrow shaft can always be oriented on the arrow rest of a bow so that the side of greater stiffness faces the bow. Orientation of the side of the shaft having greater stiffness toward the bow results in greater accuracy of arrow flight.
Other aspects and features of the arrow systems provided herein may be better appreciated as the same become better understood with reference to the specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings include:

FIG. 1 a is a side view of an assembled arrow provided in accordance with aspects of the present invention;

FIG. 1 b is an exploded view of the arrow of FIG. 1 provided in accordance with aspects of the present invention

FIGS. 2 a-2 e are side cross-sectional views of a preferred locking insert assembly in accordance with aspects of the present invention;

FIGS. 3 a and 3 b are side cross-sectional views of a preferred arrow head in accordance with aspects of the present invention.

FIGS. 4 a and 4 b are end and side cross-sectional side views of a preferred nock in accordance with aspects of the present invention.

FIGS. 5 a and 5 b are end and side cross-sectional side views of a preferred retaining sleeve in accordance with aspects of the present invention.

FIGS. 6 a and 6 b are end and side cross-sectional side views of a preferred fletching mechanism in accordance with aspects of the present invention.

FIGS. 7 a and 7 b are end and side cross-sectional side views of a preferred rearward end of an arrow shaft in accordance with aspects of the present invention.

DETAILED DESCRIPTION

The present invention provides arrow assemblies for use in target shooting as well as hunting. With reference to FIG. 1, there is shown an exemplary arrow assembly 10 according to the invention. FIG. 2 shows an exploded view of various components of the arrow assembly of FIG. 1. The arrow assembly 10 includes a shaft 120, an arrow head 150, a locking insert 130 for receiving the arrow head, a fletching assembly 110, and a nock assembly 100.
In the exemplary embodiment of FIG. 1, the arrow assembly 10 includes an arrow shaft 120 having a longitudinal hollow shaft body 126 on which an arrow head 150, fletching 110 and nock are mounted. The shaft 120 may be made of any other suitable material including metal, e.g., aluminum, plastic, wood, graphite and/or a composite material. In one embodiment, the shaft 120 is made from a light weight material such as aluminum or fiber reinforced plastic. Some examples of fiber reinforced plastic materials include, but are not limited to, fiberglass composites and carbon fiber composites.
The arrow shaft 120 has an outer diameter defined by an external surface 125 and has an internal diameter defined by an internal surface 124. The diameter of the arrow shaft 120 may vary ad desired. The length of the arrow shaft will typically depend on the user's draw length and will normally be in the range of from about 24 inches to about 31 inches. Typically, the outer diameter of an arrow shaft will be from about 0.250 inch to about 0.406 inch and the wall thickness will be from about 0.0156 inch to solid depending on the material and the desired stiffness. In one exemplary embodiment, the arrow shaft 120 made of carbon fiber material has an outer diameter of 0.296 inches and a constant wall thickness of 0.020 inches.
The degree of stiffness, frequently called the “spine,” indicates the arrow shaft's resistance to bending. “Archer's paradox” occurs when an arrow is released from the bow and the forward thrust of the bow string causes the shaft to flex in one direction and then return back as it speeds down range. Too little stiffness causes an arrow's flight to veer in one direction and too much stiffness tends to cause the arrow's flight to veer the opposite direction.
The spine of an arrow is typically determined using a spine test. In the spine test, a standard length of the arrow shaft 120 is supported at its ends while a weight, e.g., two pounds (0.91 kg), placed on the middle of the arrow shaft 120. The deflection of the middle of the shaft is measured to determine the stiffness of the arrow system 10.
The stiffness of a tubular arrow shaft tends to be non-uniform. This is due, for example to the method of manufacturing arrow shafts which result in an arrow shaft 120 having a non-uniform stiffness. During the manufacturing process, one side of the arrow shaft may have a thicker wall as there is an overlap of material at the juncture where two edges of a sheet of material overlap to form a tubular shaft body 126. This area of overlap is generally parallel to the axis of the arrow shaft. The shafts are center ground to create a uniform wall thickness. Nevertheless, the “side” of the shaft on which the overlap occurred will have a greater stiffness than the rest of the shaft. A mark, e.g., one or more words or symbols (e.g., a colored dot) may be placed on the exterior of the arrow shaft 120 to indicate the “side” of the shaft, i.e., the area of overlap that has greater stiffness. A determination of the side of greater stiffness can be don with the same device used for measuring overall stiffness. This is done by hanging a weight from the middle of the arrow shaft and placing a measuring device on the topside of the arrow by rotating the shaft slowly you can determine the stiffest side with the measuring device or spine test. The results typically show that one side of the shaft has more stiffness than the remainder of the shaft.
It has been found that consistently orienting the side of the arrow shaft with the greatest stiffness toward the bow reduces the inaccuracy due to “archers paradox.”
Still referring to FIG. 2, in an exemplary embodiment, the arrow head 150 is threadably attached to the shaft 120 by a locking insert 130. The locking insert 130 includes an annular flange at its forward end and a generally cylindrical body extending rearwardly from the flange. The outer diameter of the flange is preferably the same as the outer diameter of the arrow shaft 120. The outer diameter of the insert body is slightly less than the inner diameter of the arrow shaft 120 so that it may be fit snugly into the forward end of the arrow shaft 120.
At least the rearward portion of the insert body is tapered slightly radially inwardly as it extends rearwardly. The inner surface of this portion is threaded. This rearward portion has at least one, and preferably two or more slits 138 that extend from the rearward end of the shank forwardly a distance sufficient to create at least one and preferably at least two segments that can be expanded radially outwardly against the interior surface of the shaft, e.g., with the use of an Allen wrench or the like. In one embodiment of the invention, the rearward portion of the shank comprises two diametrically opposed slits.
In accordance with one embodiment of the invention, a locking set screw 140 may be threaded into the interior threaded, rearward portion of the insert body to expand the segments radially outwardly against the shaft wall to anchor the insert in place. In this arrangement, the insert may be loosened and rotated to the extent desired by simply loosening the set screw. Rotation of the insert may be desired if a particular orientation of the arrow head (assuming a non-uniform arrow head, e.g., a broad head) to the stiff side of the arrow shaft is desired or alignment with the fletching
Use of an expandable locking insert eliminates the need of using glues or other adhesive materials to mount the insert 130 on the shaft 120 thus insuring the insert to be in perfect alignment with axis of shaft.
The arrow head 150 has a tip and a shank that extends rearwardly from the tip into the insert 130. The arrow head 150 can be made from metal, horn, or other hard materials and is preferably an integral, one-piece construction. Preferably, the arrow head 150 is made of steel.
In one embodiment of the invention, the tip 152 is bulbous at its forward end, preferably generally spherical or ball shaped. It has been found that such a design reduces damage to layered targets that are generally made from foam sheeting. Upon impact, the bulbous tip 152 does not cut into the layers of the target like a pointed tip does. Rather, the tip 152 moves or displaces the layers of the target as it enters. It has also been found that the bulbous tip makes the arrow easier to be removed from a target. The bulbous tip 152 is supported by a neck 154 which is preferably tapered or conical in shape. The base, i.e., rearward end, of the neck has a diameter about the same as the diameter of the arrow shaft.
The shank 156 extends rearwardly from the base of the neck 154. In one embodiment of the invention, the shank 156 has two sections, the first being an elongated, generally cylindrical body having a constant outer diameter about the same as the inner diameter of the forward portion of the locking insert 130. The difference in diameter between the shank and the base of the neck creates a circumferential shoulder 155 at the junction of the base of the neck 154 and the forward end of the shank 156. The shank further comprises a second section rearward of the first section at least of portion of which is threaded. The arrow head 150 is mounted to the arrow shaft 120 by insertion of the shank 156 into the locking insert 130 and rotating the arrow head enabling the threaded portion of the shank to seat into the threaded portion of the insert. The arrow head is rotated until the base of the neck tightly engages the annular flange of the locking insert.
In another exemplary embodiment of the invention, the length of the shank of the portion of the arrow head is increased so that it performs the function of the set screw, i.e., expanding the rearward segments of the insert against the arrow shaft wall. In this embodiment, there is no need for the locking insert to include a separate set screw.
In one exemplary embodiment, exterior surfaces of the shaft 126, the locking insert flange 132, and neck 155 of the arrow head 150 create a smooth and seamless surface. In this way, the arrow system 10 has both good dynamic flight characteristics and good aerodynamic characteristics.
FIGS. 3-6 shows a rearward end of the arrow assembly 10 that includes slits 122 within a shaft 126 to accommodate a fletching mechanism 110 to be inserted thereto, a retaining sleeve 108, and a nock 100. The slits 122 are symmetrically spaced-apart about the circumference of the shaft. The slits 122 are generally longer than a longest length of fletching mechanism 110 to accommodate both the fletching mechanism 110 and a retaining sleeve 108, and extend forwardly from the rearward end of the arrow shaft 120. An exemplary slit length is the length of the fletching plus from about ⅜ to ½ inch. The slits may be straight, i.e., parallel to the axis of the shaft and to each other or may have a slight vertical curve, e.g., pitch of from 0° to about 10°, preferably about 5°. The pitch may be right handed or left handed, but right handed is preferred so that the arrow tip does not unscrew upon impact with target.
The fletching mechanism 110 is designed to provide a small amount of drag used to stabilize the flight of the arrow. It is also designed to keep the arrow oriented in the direction of travel by damping down the tendency to pitch or yaw. The fletching mechanism 110 comprises a central spine and a plurality of fletchings or vanes extending radially outwardly from the spine. For example, FIG. 5 shows a fletching mechanism 110 having a four plastic vanes 112 connected together along a central spine. In this embodiment, each vane 112 has first tapered end and a second rounded end, where the first tapered end has a gentler slope than the second end. It is understood, however, that the size and shape of the spine and vanes may vary as desired. The vanes 112 may be made of hard or soft plastic or fabric materials, or even feathers. Suitable plastic materials include celluloid, polyethylene, vinyl chloride, vinyl acetate. In one exemplary embodiment, the vanes 112 are separately cut from such materials and connected to the central spine. In another embodiment, the vanes 112 and spine are made of plastic and are molded in one piece. FIG. 5A is a cross sectional view of the fletching mechanism 110 having four vanes 112. The vanes 112 are spaced at an equal distance apart and are identical in size and shape. The spine may be made of the same material as the vanes or any other any suitable material, e.g., plastic, metal, composites or the like. While the arrows utilizing fletching mechanisms of the present invention may be used with any style bow and any style arrow rest. Preferred arrow rests include a retractable arrow rest or a wisker biscuit type arrow rest.
The fletching mechanism 110 is mounted on the arrow shaft by sliding the fletching mechanism forwardly from the rearward end of the shaft 120 so that the spine of the fletching mechanism extends into the interior of the shaft and the vanes extend outwardly from the spine and through the slits.
The fletching mechanism is secured in place on the arrow shaft 120 by a nock assembly 100 which comprising a nock 102 and a retaining sleeve 108. With reference to FIG. 3, the nock 102 generally has an exterior portion 105 including a pair of spaced apart facing prongs 101 that form a slot 103 transverse to the axis of the shaft for receiving a bow string. The diameter of the exterior portion 105, at least at its forward end, is preferably about the same as the diameter of the shaft 120. The nock further includes an insert portion 106 having an annular hollow body for inserting into the arrow shaft 120. Accordingly, the outer diameter of the insert portion 106 is slightly less than the inner diameter of the shaft 120. A circumferential shoulder 104 at the junction of the exterior portion 105 and the insert portion 106. Preferably, the circumferential shoulder 104 has the same outer diameter as that of the arrow shaft.
The insert portion 106 has a plurality of slits 107 at its forward end. The number of slits 107 in the nock insert is the same as the number of the vanes 112 of the fletching mechanism 110. In one exemplary embodiment, there are four slits 107 in the insert portion 106 of the nock 102. FIG. 3A is a cross sectional view of the nock 102 having four nock slits 107 equally spaced apart. In this arrangement, upon inserting the nock 102 into the arrow shaft 120, the circumferential shoulder 104 of the nock 102 engages the rearward end of the shaft 120, four slits 107 of the nock 102 receive the rearward edges of the vanes 112 of the fletching mechanism 110.
In the exemplary embodiments, the four slits 122 of the shaft body 126, the four vanes 112 of the fletching mechanism 110, and retaining sleeve 205 and the four slits 107 of the insert portion 106 of the nock 102 all cooperate with each other to secure the fletching mechanism 110 in place and nock in place.
The fletching mechanism 110 and the nock 102 are further secured with the retaining sleeve 108. With reference to FIGS. 4 and 4A, a side view and a cross sectional view of the retaining sleeve 108 is shown. The retaining sleeve 108 has an annular body with a forward end and a rearward end. The inner diameter is about the same as the outer diameter of the shaft 120 The retaining sleeve 108 is placed around the shaft 120 rearward of and adjacent to the inserted fletching mechanism 110. The insert portion of the nock 102 is then inserted into the rearward end of the shaft 120, the slits 107 of the insert portion 106 engaging the vanes 112 of the fletching mechanism 110 within the arrow shaft 120. The retaining sleeve 108 is then slid rearwardly over the shaft 120 and nock insert portion 106 to prevent the shaft form expanding outwardly due to the slits in the shaft 120 thereby creating a tight engagement with the shaft and nock. In this arrangement, the retaining sleeve 108 secures and holds both the fletching mechanism 110 and the nock 102 in place at the rearward end of the arrow shaft. 10.
In one exemplary embodiment, at least a lengthwise portion of the retaining sleeve 108 has a conical shape such that the outer diameter of the retaining sleeve increases from the forward end to the rearward end of that portion. Such a shape creates a vortex as the arrow is n flight helping to reduce turbulence created by the vanes or fletchings and to further improve the accuracy of the flight.
Although limited embodiments of the arrow systems and their components have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. For example, the arrow systems may be made in different lengths, sizes, and style. The shape and size of the arrow head and the fletching mechanism may be different, and the materials used may be a composite. Accordingly, it is to be understood that the arrow assemblies and their components constructed according to principles of this invention may be embodied other than as specifically described herein. The invention is defined in the following claims.

Claims

1. An arrow assembly comprising:

a generally tubular arrow shaft having forward and rearward ends and inner and outer surfaces;

a locking insert mountable in the forward end of the shaft and having at least one segment that is expandable radially outwardly to engage the inner surface of the shaft to anchor the locking insert in the forward end of the shaft;

an arrow head connectable to the locking insert;

a nock mountable to the rearward end of the shaft; and

a fletching mountable to the shaft at a location along the length of the shaft forward of the nock.

2. The arrow assembly of claim 1, wherein the arrow head comprises an forward portion and a rearward portion and wherein the forward portion comprises a bulbous tip.

3. The arrow assembly of claim 1, wherein the locking insert comprises an annular flange at its forward end and a body portion extending rearwardly from the annular flange, the annular flange having an outer diameter about the same diameter as the diameter of the arrow shaft and the body portion having an outer diameter slightly less than the inner diameter of the arrow shaft.

4. The arrow assembly of claim 3, wherein the body of the locking insert is tubular and comprises a rearward portion having interior threads and at least one slit extending forwardly from the rearward end of the rearward portion to thereby form at least one segment that can be expanded radially outwardly.

5. The arrow assembly of claim 4 wherein the interior surface of the threaded rearward portion of the insert body tapers rearwardly and radially inwardly.

6. The arrow assembly of claim 5 further comprises a locking set screw for threading into the threaded rearward portion of the insert body, said locking set screw having a diameter that, when threaded into the threaded rearward portion of the inside body, expands the at least one expandable segment radially outwardly.

7. The arrow assembly of claim 5, wherein the arrow head comprises a rearward portion threadable into the threaded rearward portion of the insert body, said rearward portion of the arrow head having a diameter that, when threaded into the threaded rearward portion of the inside body, expands the at least one expandable segment radially outwardly.

8. An arrow assembly comprising:

an arrow shaft having forward and rearward ends and a plurality of slits extending forwardly from its rearward end;

a fletching mechanism mounted on the shaft having a central spine and a number of symmetrically spaced apart equal to the number of slits in the shaft, each vane extending radially outwardly from the spine and extending through a slit in the arrow shaft; and

a nock mounted at the rearward end of the shaft.

9. The arrow assembly of claim 8, wherein the nock comprises a tubular forward portion and a rearward portion, the forward portion extends into the interior of rearward end of the shaft and comprises at least one slit at its forward end for receiving the rearward edge of a vane of the fletching mechanism, and wherein the rearward portion comprises a slot for receiving a bow string.

10. The arrow assembly of claim 8 further comprising an annular retaining sleeve outer circumference of the arrow shaft at the rearward end of the shaft to secure the nock to the arrow shaft.

11. The arrow assembly of claim 9, wherein the shaft has a side of greater stiffness and comprising a mark on the exterior of the shaft indicating the side of greater stiffness.

12. The arrow assembly of claim 9, wherein the slits in the arrow shaft are straight and parallel to the longitudinal axis of the shaft.

13. The arrow assembly of claim 9, wherein the slits extend helixially about the longitudinal axis of the shaft.

14. The arrow assembly of claim 9, wherein the slits extend helixially about the longitudinal axis of the shaft at an angle of from about 0° to about 10° to the longitudinal axis of the shaft.

15. An arrow assembly comprising:

a hollow arrow shaft having a forward end and a rearward end and a plurality of slits extending forwardly from the rearward end;

a tubular expandable locking insert mounted in the interior of the forward end of the arrow shaft, said locking insert having at least one expandable segment engaging the inner surface of the arrow shaft to releasably secure the insert to the shaft;

an arrow head having a bulbous tip portion mounted on the locking insert;

a fletching mechanism having a central spine and plurality of vanes extending radially outwardly from the spine, said fletching mechanism mounted in a rearward portion of the arrow shaft wherein the spine is within the interior of the shaft and the vanes extend through the slits in the shaft; and

a nock mountable to the rearward end of the arrow shaft.

16. The arrow assembly of claim 15, wherein the nock comprises a tubular forward portion and a rearward portion, the forward portion extends into the interior of rearward end of the shaft and comprises at least one slit at its forward end for receiving the rearward edge of a vane of the fletching mechanism, and wherein the rearward portion comprises a slot for receiving a bow string.

17. The arrow assembly of claim 15 further comprising an annular retaining sleeve outer circumference of the arrow shaft at the rearward end of the shaft to secure the nock to the arrow shaft.

18. The arrow assembly of claim 15, wherein the shaft has a side of greater stiffness and comprising a mark on the exterior of the shaft indicating the side of greater stiffness.

19. The arrow assembly of claim 15, wherein the slits in the arrow shaft are straight and parallel to the longitudinal axis of the shaft.

20. The arrow assembly of claim 15, wherein the slits in the arrow shaft are straight and parallel to the longitudinal axis of the shaft.

21. The arrow assembly of claim 15, wherein the slits extend helixially about the longitudinal axis of the shaft.