U.S. patent application number 11/167080 was filed with the patent office on 2007-04-19 for center-fire bow.
Invention is credited to Kent M. Perry.
Application Number | 20070084451 11/167080 |
Document ID | / |
Family ID | 37947012 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070084451 |
Kind Code |
A1 |
Perry; Kent M. |
April 19, 2007 |
Center-fire bow
Abstract
A bow includes a bow frame with a geometric center, and a frame
outlining the geometric center. The pivoting center thrust points
are disposed within the frame, and a bow handle is pivotally
attached to the vertical pivoting center thrust points at a
position offset from the geometric center. The bow is configured
such that a user can fire an arrow through the geometric center of
the bow, and with pivoting center thrust points it allows free
pivoting of the bow about two substantially orthogonal axes.
Inventors: |
Perry; Kent M.; (Koosharem,
UT) |
Correspondence
Address: |
Kent Perry
275 No 300 W
P.O. Box 440051
Koosharem
UT
84744
US
|
Family ID: |
37947012 |
Appl. No.: |
11/167080 |
Filed: |
October 13, 2005 |
Current U.S.
Class: |
124/23.1 ;
124/88 |
Current CPC
Class: |
F41B 5/14 20130101 |
Class at
Publication: |
124/023.1 ;
124/088 |
International
Class: |
F41B 5/00 20060101
F41B005/00 |
Claims
1. A bow, comprising: a bow frame having a geometric center; a
window frame partially surrounding the geometric center, such that
a user of the bow can fire an arrow through the geometric center of
the bow; a gimbal, pivotally attached to the bow frame; and a bow
handle, pivotally attached to the gimbal at a position offset from
the geometric center of the bow, the gimbal and bow handle being
configured to allow free pivoting of the bow about two
substantially orthogonal axes.
2. A bow in accordance with claim 1, wherein the gimbal is
pivotally attached to the window frame.
3. A bow in accordance with claim 1, wherein the bow handle is
disposed at a 45 degree angle.
4. A bow in accordance with claim 1, wherein the window frame
includes pivoting center thrust points to connect the window frame
to the bow handle.
5. A bow in accordance with claim 1, wherein the window is a
C-frame.
6. A bow in accordance with claim 1, further comprising a
stabilizer bar, rearwardly extending from the bow, configured to
contact an arm of a user of the bow, so as to compensate for moment
generated by the offset between the geometric center and the
position of the handle.
7. A bow in accordance with claim 6, wherein the stabilizer bar is
connected to the bow handle.
8. A bow in accordance with claim 1, further comprising: a bow
string, connected between opposing ends of the bow frame, having a
center and a nock point at the center, the bow being configured
such that a user can fire the arrow through the geometric center of
the bow with the arrow nocked at the nock point.
9. A bow in accordance with claim 1, wherein the bow frame further
comprises: an upper limb, a lower limb, and a riser interconnecting
the upper and lower limbs, the window frame comprising a portion of
the riser.
10. A bow in accordance with claim 9, wherein the limbs are
selectively removable from the riser.
11. A bow in accordance with claim 9, further comprising: a bow
string, connected between the upper limb and the lower limb, having
a center and a nock point substantially at the center, the bow
being configured such that a user can fire the arrow through the
geometric center of the bow with the arrow nocked at the nock
point.
12. A bow in accordance with claim 11, further comprising: an upper
cam mechanism, disposed at an extreme upper end of the upper limb,
and operatively connecting the bow string to the upper limb; a
lower cam mechanism, disposed at an extreme lower end of the lower
limb, and operatively connecting the bow string to the lower limb;
and a tension line, interconnected between the upper cam mechanism
and the lower cam mechanism, the cam mechanisms and tension line
being configured to reduce tension on the bow string and increase
tension on the tension line when the bow string is fully drawn.
13. A bow in accordance with claim 1, wherein the window is
configured to allow a concurrent full view of a center target
region aligned with an arrow trajectory at the same time as release
of the arrow through the geometric center.
14. A bow in accordance with claim 1, further comprising an arrow
rest, attached to the window frame and extending thereinto,
configured to support an arrow shaft so as to place a center axis
of the arrow shaft substantially at the geometric center.
15. A bow, comprising: a bow frame, having a geometric center; a
C-frame, integrally disposed in a center of the bow frame and
surrounding a portion of a geometric center; a gimbal, pivotally
attached to the window frame; a bow handle, pivotally attached to
the gimbal and offset below the geometric center, the bow handle
being configured to pivot about an axis that is substantially
perpendicular to a pivoting axis of the gimbal, so as to allow free
pivoting of the bow about two substantially orthogonal axes, the
bow being configured such that a user can fire an arrow through the
geometric center of the bow with the arrow nocked at the nock
point.
16. A bow in accordance with claim 15, wherein the gimbal is
pivotally attached to the C-frame.
17. A bow in accordance with claim 15, further comprising a
stabilizer bar, rearwardly extending from the bow handle,
configured to contact an arm of a user of the bow, so as to
compensate for moment generated by the offset between the geometric
center and the position of the handle.
18. A bow in accordance with claim 15, further comprising an arrow
rest, attached to the window frame and extending thereinto,
configured to support an arrow shaft so as to place a center axis
of the arrow shaft substantially at the geometric center.
19. A bow in accordance with claim 14, wherein the bow frame
further comprises: an upper limb; a lower limb; and a riser,
interconnecting the upper and lower limbs, the window frame
comprising a central portion of the riser.
20. A bow, comprising: a bow frame, having a longitudinal axis and
a geometric center; a bow string, connected between opposing ends
of the bow frame, having a center and a nock point at the center,
and being oriented substantially parallel to the longitudinal axis;
a window frame located around a portion of the geometric center of
the bow, the window being integrally disposed in a center of the
bow frame; a gimbal, disposed within the window and configured to
pivot about an axis that is substantially perpendicular to the
longitudinal axis of the bow frame; a bow handle, attached to the
gimbal and offset from the geometric center, the handle being
configured to pivot about an axis that is substantially parallel to
the longitudinal axis of the bow, the gimbal and bow handle being
configured to allow free pivoting of the bow about two axes
relative to the handle, the pivotal axis of the gimbal and the
pivotal axis of the bow handle intersecting substantially at the
geometric center of the bow; and a stabilizer bar, extending from
the bow, configured to contact an arm of a user of the bow, such
that a user can fire an arrow through the geometric center of the
bow with the arrow nocked at the nock point, the stabilizer bar
compensating for moment generated by the offset between the
geometric center and the position of the handle.
Description
PRIORITY CLAIM
[0001] The present application claims priority from U.S.
provisional patent application Ser. No. 60/496,836, filed Aug. 21,
2003 and is a CIP of U.S. regular patent application Ser. No.
10/922,213, filed Aug. 18, 2004 entitled "Center-Fire Bow".
FIELD OF THE INVENTION
[0002] The present invention relates to archery equipment.
BACKGROUND
[0003] The bow is one of the most ancient weapons, and there have
been innumerable designs for bows over the centuries. While the
development of firearms long ago displaced bows as among the most
powerful and accurate weapons, there is still widespread use of
bows in sport hunting and target shooting. Because of this
continued enthusiasm, there have been a number of significant
improvements and changes in bows in relatively recent times. For
example, the development of the compound bow and the introduction
of lightweight resilient carbon fiber composite materials have
greatly improved the ease of use and performance of modem bows.
[0004] Despite modem improvements, however, some traditional
problems still remain. For example, the traditional straight bow
fires the arrow to the side of the bow, causing a slight waver or
curve in the trajectory of the arrow. To eliminate this problem,
many modem bows include a lateral offset in the bow just above the
handle, allowing the arrow to be fired in line with the vertical
axis of the bow.
[0005] However, this solution to one problem actually introduces
another problem. In order to allow the archer to steady the bow,
the handle must be located at the geometric center of the bow.
Because the handle occupies the center of the bow, the arrow is
therefore necessarily fired slightly above center, and the arrow
nock must therefore contact the bowstring slightly above the
center. This offset causes the bowstring to apply differential
forces to the arrow, causing a vertical waver in the trajectory of
the arrow.
SUMMARY OF THE INVENTION
[0006] It has been recognized that it would be advantageous to
develop a bow that avoids the vertical and horizontal offsets that
affect the trajectory of an arrow.
[0007] The invention provides a bow, including a bow frame with
geometric center, and a frame supporting the geometric center. A
bow handle set on an angled bracket that is attached to the bow
frame at a position offset from the geometric center such that a
user can fire an arrow through the geometric center of the bow.
[0008] In accordance with a more detailed aspect of the present
invention, a pivoting center thrust points is disposed within the
frame, and the bow handle is pivotally attached to the pivoting
center thrust points, allowing free pivoting of the bow about two
substantially orthogonal axes.
[0009] In accordance with another more detailed aspect of the
present invention, the bow further includes a stabilizer bar,
rearwardly extending from the bow handle, configured to contact
with an arm of the user of the bow, to compensate for moment
generated by the offset between the geometric center and the
position of the handle.
[0010] Additional features and advantages of the invention will be
apparent from the detailed description which follows, taken in
conjunction with the accompanying drawings, which together
illustrate, by way of example, features of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of one embodiment of a bow in
accordance with the present invention
[0012] FIG. 2 is a close-up perspective view of the riser of the
bow of FIG. 1.
[0013] FIG. 3 is a partial front view of an alternative embodiment
of a half center-fire bow in accordance with the present
invention.
[0014] FIG. 4 is a side view of the bow of FIG. 3.
[0015] FIG. 5 is a top, partially cross-sectional view of the bow
of FIG. 3.
DETAILED DESCRIPTION
[0016] Reference will now be made to the exemplary embodiments
illustrated in the drawings, and specific language will be used
herein to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended. Alterations and further modifications of the inventive
features illustrated herein, and additional applications of the
principles of the inventions as illustrated herein, which would
occur to one skilled in the relevant art and having possession of
this disclosure, are to be considered within the scope of the
invention.
[0017] The bow of the present invention is designed so that an
arrow can be fired through a geometric center of the bow. The
geometric center has previously been occupied by the archer's hand,
rather than locating the archer's hand above or to the side of the
center. This configuration allows greater accuracy. This
re-positioning of the archer's hand is accomplished by providing a
riser that includes a C-frame or window frame through which the
arrow is fired. This C-frame allows the shooter to effectively hold
the bow from both sides of center using a gimbal-mounted
handle.
[0018] With reference to FIGS. 1 and 2, one embodiment of a bow 10
in accordance with the present invention comprises a riser 12, an
upper bow limb 14 attached to an upper limb pocket mount 16 at the
upper end 18 of the riser, a lower bow limb 20 attached to a lower
limb pocket 22 at the lower end 24 of the riser, and a bowstring 26
connected between the extremities of the limbs. The riser and limbs
together can be considered to comprise the bow frame. The bow
depicted is a compound bow, having a top cam assembly 28, a bottom
cam assembly 30, a cable 32 connected there between, and a cable
guard bar 34 extending rearwardly from the riser for deflecting the
cable out of the line of the arrow path.
[0019] The bow string also includes a pair of nock point indicator
bushings 42 for indicating the nock point 44, which represent the
proper point for aligning an arrow nock with the bow string. It
will be apparent to those skilled in the art that the bow also
includes other features not specifically mentioned, and can include
other features not shown that are well known in the art.
[0020] While the embodiment depicted in FIGS. 1 and 2 is a compound
bow, it will be apparent that the present invention is not limited
to compound bows, or limited to compound bows of the configuration
shown. Likewise, the present invention is not limited to bows
having the exact structural geometry shown in FIGS. 1 and 2. For
example, the riser 12 of the bow of FIGS. 1 and 2 includes an upper
frame 46 having a sight 48 to allow a clear view of the bow sight
38.
[0021] In the embodiment of FIGS. 1 and 2, the limb pockets 16 and
22 each include a double-tapered groove (not visible) for affixing
the limbs 14 and 20 thereinto, so that the limbs are held solidly
and cannot move. This configuration allows one to attach any type
of limb, such as compound, recurve, etc., to the riser 12 with very
little effort or time. Alternatively, as shown in the embodiment of
FIGS. 3-5, the limbs 86, 88 may be bolted to the base mounts with
bolts 89, as is common in many bows. While bolted connections can
be used, the inventor believes that limbs attached with the
double-tapered groove are more secure and more resistant to slight
movement or loosening with use.
[0022] While the bow of FIGS. 1 and 2 differ in some respects from
that shown in FIGS. 3-5, both embodiments depicted include the
center fire features described below. To provide the center-fire
capability, the riser 12, 82 advantageously includes a firing
C-frame 50, 90 or a partial window frame with pivoting center
thrust points 52, 92 disposed therein. The pivoting center thrust
points includes an L shaped member 54, 94 that is pivotally
attached to the C-frame a lateral pivot point 56, 96, and
configured to pivot about a horizontal axis 58, 98. Pivotally
attached to the bottom portion 60, 100 of the L-shaped member is a
handle set on a 45 bracket 62, 102 that is configured to pivot
about a vertical axis 64, 104. A stabilizer bar 66, 106 extends
rearwardly from the handle. It will be apparent that the
designation of horizontal and vertical axes is arbitrary, and is
primarily intended to provide a common frame of reference for
describing the bow. These designations do not necessarily relate to
the earth's horizon, given that a bow can be held and fired in a
variety of positions.
[0023] The C-frame 50, 90 is part of the riser. The C-frame can be
integrally formed as part of the riser, or the riser can be
assembled from multiple pieces. Nevertheless, those skilled in the
art will recognize that the C-frame must have sufficient structural
strength to bear the large bending forces experienced by the bow.
Ordinarily, the structure at the geometric center of a bow
(typically at the location of the handle) is the thickest and most
robust portion of the bow structure, because the bending forces are
largest at that point. However, with the bow of the present
invention, there is no structure at the geometric center. There is
only empty space. Consequently, the bending stresses that
ordinarily pass through the geometric center of the bow structure
are borne on either side of the geometric center, by the C-frame,
which creates an open window frame or partial frame around the bow
center. This configuration may use a structure for the C-frame (and
also of the pivoting center thrust points 52, 92) that is
sufficient to withstand these forces.
[0024] Shown in dashed lines in the top view of FIG. 5 is a left
pivoted position 108 and a right pivoted position 110 of the handle
102 and the stabilizer bar 106 relative to the L-shaped member and
C-frame 90. Shown in dashed lines in the side view of FIG. 4 is a
forward pivoted position 112 and a rearward pivoted position 114 of
the L-shaped member 94 and handle 102. These views are not intended
to show the full range of motion of the handle and the L-shaped
member. However, these views are intended to be representative of
how these members pivot with respect to the bow structure in
general and the C-frame in particular.
[0025] With this bow configuration, the firing point 68, 116
coincides with the geometric center of the bow 10, 80 inside the
firing C-frame 50, 90, above the handle 62, 102. The firing
point/bow center coincides with the intersection of the horizontal
axis 58, 98 and the vertical axis 64, 104. With reference to FIG.
2, the arrow rest 40 is disposed directly behind the bow center 68,
between the handle 62 and the nock point 44 on the bowstring 26. A
horizontal line between the firing point and the nock point
represents the firing axis (70 in FIGS. 1-2, 118 in FIGS. 3-5) of
the bow. The firing axis may be horizontal (with respect to the
bow) and perpendicular to both the horizontal axis and vertical
axis, passing through the center point of the bow. The arrow rest
may be oriented to support an arrow in alignment with the firing
axis when the bow is drawn and an arrow is fitted on the nock
point. The result is a bow that is configured to fire an arrow
directly through the geometric center of the bow, rather than along
a line that is offset from the center.
[0026] When firing an arrow, an archer normally draws the bow (and
the rear extremity of the arrow) back to a position approximately
at the lever of his/her chin. A peep hole (not shown) is provided
in the bow string several inches above the nock point 44. With the
bow drawn, the archer looks through the peep hole and along the
cross hairs of a bow sight with the target to fire. To compensate
for the arc of the arrow with distance, the height of the peep hole
above the nock point is greater than the height of the bow sight
above the geometric center 68, so that the line of sight from the
peep hole to the cross hairs of the bow sight is slightly downward
relative to the firing axis 70. The bow sight includes several
horizontal pins, each one at a different height above the geometric
center, the lower pins corresponding to greater target distances
(by producing a line of sight that is more downward relative to the
firing axis), and the higher pins corresponding to closer target
distances (by producing a line of sight that is closer to parallel
to the firing axis).
[0027] While most archers use a bow sight as described above, a few
archers prefer to sight along the arrow itself. The present
invention makes doing so easier because the line of the arrow
(i.e., the firing axis 70) passes through the C-frame 50, 90. The
C-frame thus allows a concurrent unobstructed full view through the
C-frame of a center target region aligned with the arrow trajectory
at the same time as release of the arrow through the geometric
center 68.
[0028] As most clearly shown in FIG. 4, the main pressure point 120
of the handle 102 is located a distance D below the center point 1
16 and the firing axis 1 18. Because of this offset, a clockwise
vertical moment M (shown in the side view of FIG. 4) will be
created when the bow is drawn. To counter this moment, the
stabilizer par 106, extends rearwardly to a distance L (shown in
FIG. 5) from the base of the handle, and is configured to extend
over the archer's forearm. The stabilizer bar counter the vertical
moment M created by the vertically offset handle by placing a
downward force on the archer's forearm, allowing the user to pull
the bowstring without putting pressure on the wrist. This reduces
hindrance to the archer's aiming the bow. Because the stabilizer
bar is relatively long, the vertical force applied to the forearm
is relatively small.
[0029] With reference again to FIGS. 1-2, this bow configuration
allows an archer to effectively hold the center point 68 of the bow
10, while firing an arrow right through the center point. It also
allows the nock point 44 to be located at the exact center of the
bowstring 26, so that energy from the top cam assembly 28 and
bottom cam assembly 30 release at the same time and with the same
force. This helps eliminate any waver or sway in the arrow's flight
because of unequal forces from the top and bottom cam. Other bows
nock the arrow a little above the center of the bowstring, and
regardless of the adjustments made, there is always some sway that
is put on the arrow.
[0030] The pivoting center thrust points configuration also allows
the follow-through to be truer, regardless of how the archer holds
the wrist. Upon release of an arrow, an archer's wrist. With the
present invention, any twist in the wrist (horizontal or vertical)
is taken up by the pivoting center thrust points 52, 92, allowing
the bow 10, 80 to stay straight.
[0031] A variety of materials are suitable for manufacture of the
center-fire bow of the present invention. For ease of use,
lightweight materials are generally preferred, such as are
currently used in the manufacture of sport and hunting bows. For
example, the inventor has manufactured a bow in accordance with the
invention having an aluminum riser in the configuration shown.
Alternatively, the riser could be manufactured of other materials,
such a wood, titanium, polymers, fiberglass, carbon fiber
composites, etc.
[0032] By way of example, and without limitation, the invention can
be described as a bow, including a bow frame with a geometric
center, and a C-frame outlining the geometric center. The pivoting
center thrust points are disposed within the C-frame, and a bow
handle is pivotally attached to the pivoting center thrust points
at a position offset from the geometric center. The bow is
configured such that a user can fire an arrow through the C-frame,
through the geometric center of the bow, the gimbal and bow handle
allowing free pivoting of the bow about two substantially
orthogonal axes.
[0033] It is to be understood that the above-referenced
arrangements are only illustrative of the application of the
principles of the present invention. Numerous modifications and
alternative arrangements can be devised without departing from the
spirit and scope of the present invention. While the present
invention has been shown in the drawings and fully described above
with particularity and detail in connection with what is presently
deemed to be the most practical and preferred embodiment(s) of the
invention, it will be apparent to those of ordinary skill in the
art that numerous modifications can be made without departing from
the principles and concepts of the invention as set forth
herein.
* * * * *