Arrow insert

An arrow insert dimensioned and configured for engagement in a hollow arrow shaft having a cylindrically shaped wall of a predetermined inner and outer diameter disposed about a longitudinal axis. The insert includes a cylindrical insert body of a first diameter adapted to be disposed within one end of the arrow shaft. An enlarged shoulder on one end of the insert body is provided for preventing the insert body from sliding too far into the arrow shaft. A pair of annular alignment rings having outer diameters slightly larger than the inside diameter of the arrow shaft are disposed in a spaced relationship with respect to each other on the exterior of the cylindrical insert body for the purpose of insuring that the insert body will be disposed within the arrow shaft so that the longitudinal axis thereof is in alignment with the longitudinal axis of the arrow shaft, whether or not the end of the arrow shaft is cut off straight, has metal burrs thereon or whether the shoulder or alignment flange is properly seated against the end of the arrow shaft. A glue trap is provided between the annular alignment rings, the insert body and an inner surface of the arrow shaft.

TECHNICAL FIELD 
The present invention relates to an insert for a hollow arrow shaft, and 
more particularly to such an insert which assures that a longitudinal axis 
of the insert will always be in alignment with the longitudinal axis of 
the hollow arrow shaft. 
BACKGROUND ART 
Commercially available aluminum, fiberglass and other non-wooden arrows are 
usually formed in a tubular shaft configuration. Plastic nocks, adapted to 
be received on a bow string are attached to the rear end of such shaft. 
Various types of points, such as target points, field point, blunts, 
broadheads for hunting, fishing points, etc., are attached to the other 
end of the shaft to complete the arrow. 
After an arrow shaft has been cut to a desired length, various structures 
have been utilized to attach a point to the front of the arrow shaft and a 
nock to the other end thereof. Typically, this attachment structure is a 
metal cylindrical structure adapted to be inserted into one open end of 
such tubular arrow and glued in place. The insert has something on it to 
permit attachment of the desired point or nock to it. This may be a 
surface to glue the point or nock thereto, but a common construction for 
points is a central threaded bore adapted to threadably receive a metal 
point body with threads formed on one end thereof. 
Because the metal insert is glued to the interior of the front end of the 
tubular arrow shaft, usually by heat meltable glue, the outer diameter of 
such metal insert is not formed with close tolerances with respect to the 
interior diameter of the arrow shaft so that there will be room for an 
adequate amount of glue between the insert and the interior of the shaft. 
Because of this loose fit between the insert and the shaft, an alignment 
flange is provided on the front end of the metal insert for abutment with 
the extreme front annular surface of the shaft for causing the 
longitudinal axis of the metal insert, and thereby the longitudinal axis 
of a threaded bore, if present, to be in alignment with the longitudinal 
axis of the arrow shaft. This structure for achieving alignment works fine 
if the end of the shaft is cut off absolutely straight and no burrs or 
other irregularities are present on the extreme front end of the arrow 
shaft, and if adequate pressure is exerted on the insert to make sure that 
the alignment shoulder or flange is in abutment with the extreme end of 
the shaft. But as it turns out, it is a common problem that the insert is 
not properly seated or that shafts are not cut off straight or have metal 
burrs thereon, especially when such arrows are custom cut to a specific 
length for individual archers. Consequently, it is a common problem that 
arrow points sometimes arenot in alignment with the longitudinal axis of 
the arrow shaft, and it is well known that arrows with such a problem do 
not fly straight and true. For example, if a five-sixteenth inch diameter 
shaft is cocked one thousandth of an inch, then a point, such as on 
broadhead, extending three inches out therefrom is approximately 
eight-thousandths of an inch off center. 
Accordingly, there is a need for an arrow shaft insert for attaching the 
front end of a tubular arrow shaft to an arrow point which will insure 
proper alignment irrespective of irregularities or straightness of cut on 
the extreme end of the arrow shaft, or whether the insert alignment flange 
or shoulder is properly seated against the extreme end of the arrow shaft. 
DISCLOSURE OF THE INVENTION 
The present invention relates generally to a hollow arrow shaft having a 
cylindrically shaped wall of a predetermined inner and outer diameter 
disposed about a longitudinal axis. The insert includes a cylindrical 
insert body of a first diameter adapted to be disposed within one end of 
the arrow shaft. An enlarged shoulder on one end of the insert body is 
provided for preventing the insert body from sliding too far into the 
arrow shaft. A pair of annular alignment rings having different outer 
diameters are disposed in a spaced relationship with respect to each other 
on the exterior of the cylindrical insert body for the purpose of insuring 
that the insert body will be disposed within the arrow shaft so that the 
longitudinal axis thereof is in alignment with the longitudinal axis of 
the arrow shaft, whether or not the end of the arrow shaft is cut off 
straight, has metal burrs thereon or whether the shoulder is properly 
seated against the end of the arrow shaft. A glue trap is provided between 
the annular alignment rings, the insert body and an inner surface of the 
arrow shaft. 
An object of the present invention is to provide an improved insert for the 
front or rear end of an arrow shaft so a nock or a point can be attached 
thereto. 
Another object of the present invention is to provide an alignment 
structure for arrow shaft inserts which will automatically align the 
longitudinal axis of the insert with the longitudinal axis of the shaft 
irrespective or irregularities or straightness of cut on the extreme front 
end on the arrow shaft. 
Another object of the present invention is to provide a structure for 
trapping glue between alignment rings on a structure of the aforementioned 
type so that adequate glue is present to prevent the insert from 
loosening. 
Other objects, advantages and novel features of the present invention will 
become apparent from the following description of the best mode for 
carrying out this invention.

BEST MODE FOR CARRYING OUT THE INVENTION 
Referring now to the drawings, wherein like reference numerals designate 
identical or corresponding parts throughout the several views, FIG. 1 
shows an arrow (10) constructed in accordance with the present invention. 
Referring to FIG. 2, it is noted that one end (11) of the arrow (10) has a 
front edge surface (12) thereon and a central opening (13) adapted to 
receive an insert (14) constructed in accordance with the present 
invention. A field point (15) is also shown in FIG. 2, and is adapted to 
be threadably engaged with threaded portion (16) inside of insert (14). It 
is to be understood that other types of points, such as target points, 
blunts, broadheads having blades thereon for hunting large game, fishing 
point, or many other types of arrow points (10) can be attached to the 
insert instead of a field point (15) as is shown in FIGS. 1 and 2. 
Referring now to FIGS. 3-5, it is noted that the insert (14) has a main 
body portion (18) having a central bore (19) disposed therethrough, with 
threads (16) being disposed on one end thereof. This bore (19) and threads 
(16) are formed about a longitudinal axis (20). An enlarged shoulder (21) 
is disposed on one end of the insert (14) and extends from the main body 
(18) of the insert (14) to an outer diameter thereof, such other diameter 
typically being matched to the outer diameter of the shaft (11) of the 
arrow (10). 
A pair of alignment rings (22 and 23) are disposed on the exterior of the 
insert body (18) of the insert (14), as can readily be seen in FIGS. 3, 5, 
and 6. The external diameter of alignment ring (22) is larger than the 
outer diameter of the alignment ring (23), and alignment ring (22) forms a 
press fit with the interior of the shaft (11). Since these annular 
alignment rings (22 and 23) are slightly larger than the inside diameter 
of the opening (13) in the end (12) of the shaft (11), proper alignment is 
achieved. 
These close tolerances between the diverse exterior diameters of the 
annular alignment rings (22 and 23) and the interior diameter of the arrow 
shaft (11), in combination with the fact that the annular alignment rings 
(22) are spaced apart by a substantial distance, will cause the 
longitudinal axis (20) of the insert (14) to always be in alignment with 
the longitudinal axis of the arrow shaft (11). 
The exterior of the insert body (18) also has a plurality of grooves (24, 
25 and 26) disposed therein for receiving and holding an adhesive, so that 
when such glue or adhesive (28) has cured by changing from a liquid to a 
solid condition, the insert (14) will remain in the position shown in FIG. 
6, with respect to the shaft (11), unless such adhesive (28) is melted or 
otherwise disturbed. 
To install the insert (14) to the arrow shaft (11), typically a field point 
(15) or the like, is threadably attached by threading the thread (17) of 
the field tip (15) into the thread (16) of the insert (14). Then an 
adhesive or glue (28) is melted and applied to the exterior of the insert 
(14). Such insert (14) is then pushed into the end of the arrow shaft (11) 
from the position shown in FIG. 2 to the position shown in FIG. 6. In the 
process of inserting the insert (14) into the shaft (11), a portion of the 
glue or adhesive (28) will be trapped between the insert body (18), the 
inside of the shaft (11) and the annular alignment rings (22 and 23). the 
rest of the glue or adhesive (28) will be located in whatever space is 
available to receive it; in particular, this glue or adhesive will extend 
into the grooves (24 and 25). 
Ideally, in the process of gluing the insert (14) into the end of the shaft 
(11), the annular shoulder (21) on the front end of the insert (14) will 
abut and extend directly along the front edge (12) of the shaft (11). But, 
if for any reason this relationship is not obtained, for example because 
enough pressure was not exerted on the insert to cause such seating, or 
because the edge (12) is not straight and flat because of a crooked cut, 
or because of having burrs or other irregularities thereon, the alignment 
rings (22) will nevertheless positively assure that the longitudinal axis 
of the insert (14) will be in alignment with and coincident with the 
longitudinal axis of the tubular arrow shaft (11). 
Accordingly, it will be appreciated that the preferred embodiment disclosed 
herein does indeed accomplish the aforementioned objects. Obviously, many 
modifications and variations of the present invention are possible in 
light of the above teachings. For example, the insert (14) shown could 
have a point attached thereto in ways other than as shown, such as having 
a fixture thereon to which such a point is glued. Also, alignment ring 
structures of other configuration and relative spacing between such 
structures can be utilized. It is therefore to be understood that, within 
the scope of the appended claims, the invention may be practised otherwise 
than as specifically described.