U.S. patent application number 12/417437 was filed with the patent office on 2009-10-15 for two-track system for dual cam compound bow.
Invention is credited to Kevin D. Strother.
Application Number | 20090255520 12/417437 |
Document ID | / |
Family ID | 40897950 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090255520 |
Kind Code |
A1 |
Strother; Kevin D. |
October 15, 2009 |
TWO-TRACK SYSTEM FOR DUAL CAM COMPOUND BOW
Abstract
The present invention comprises a two-track cam assembly wherein
the cam assembly has a bowstring component for housing the
bowstring and a power cable component that allows for the take up
and let out of the power cable on opposing ends of the power cable
component, effectively creating a two-track cam assembly. The
efficiency rating of the device achieves 95.8%. The cam assembly
can come in a unitary or modular form and further each component
(i.e. the bowstring or power cable component) can be in a circular
or non-circular form.
Inventors: |
Strother; Kevin D.; (Moses
Lake, WA) |
Correspondence
Address: |
HISCOCK & BARCLAY, LLP
2000 HSBC PLAZA, 100 Chestnut Street
ROCHESTER
NY
14604-2404
US
|
Family ID: |
40897950 |
Appl. No.: |
12/417437 |
Filed: |
April 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12330871 |
Dec 9, 2008 |
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12417437 |
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61062380 |
Jan 25, 2008 |
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Current U.S.
Class: |
124/25.6 |
Current CPC
Class: |
F41B 5/14 20130101; F41B
5/105 20130101; F41B 5/1411 20130101; Y10S 124/90 20130101; F41B
5/10 20130101 |
Class at
Publication: |
124/25.6 |
International
Class: |
F41B 5/10 20060101
F41B005/10 |
Claims
1. A compound bow comprising: a handle portion; two limb portions
each having at least one cam assembly rotatably mounted on a limb;
the cam assembly comprising: a bowstring cam component having a
track for receiving a bowstring; a power cable cam component having
a take up portion and a let out portion; the take up portion and
let out portion each comprise a track for receiving a power cable;
the tracks for the take up portion and let out portion are
substantially coplanar.
2. The compound bow of claim 1 further comprising: two power
cables; and a bowstring; wherein the first power cable is anchored
to the first cam assembly with a portion adjacent to the first end
sitting in the take up portion track of the power cable cam
component on the first cam assembly and at its second end is
anchored to the second cam assembly with a portion adjacent to the
second end sitting in the let out portion track of the power cable
cam component on the second cam assembly; wherein the second power
cable is anchored to the first cam assembly with a portion adjacent
to the first end sitting in the let out portion track of the power
cable cam component on the first cam assembly and at its second end
is anchored to the second cam assembly with a portion adjacent to
the second end sitting in the take up portion track of the power
cable cam component on the second cam assembly; such that the
respective power cables while sitting in the tracks are
coplanar.
3. The compound bow of claim 1 wherein the tracks on the take up
portion and the let out portion of the power cable cam assembly are
part of a continuous track around at least a portion on the
periphery of the power cable cam assembly.
4. The compound bow of claim 1 wherein the tracks on the take up
portion and the let out portion of the power cable cam assembly are
non-continuous tracks on the periphery of the power cable cam
assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No.
12/330,871 filed Dec. 9, 2008, which claims the priority date of
U.S. Provisional Application Ser. No. 61/062,380, entitled
"COMPOUND ARCHERY BOW" filed Jan. 25, 2008.
FIELD OF THE INVENTION
[0002] This invention relates to compound bows, and more
specifically, it relates to a two-track system for bow strings and
power cables of the compound bow.
BACKGROUND OF THE INVENTION
[0003] Cams have been used on compound bows for some time. Compound
bows have opposing limbs extending from a handle portion which
house the cam assemblies. Typically, the cam assemblies are
rotatably mounted on an axel which is then mounted on a limbs of
bow. The compound bows have a bow string attached to the cam which
sits in a track and also, generally, two power cables that each sit
in a track on a separate component on the cam, and either anchored
to the cam or a limb/axel. When a bowstring is pulled to full draw
position, the cam is rotated and the power cables are "taken up" on
their respective ends to increase energy stored in the bow for
later transfer, with the opposing ends "let out" to provide some
give in the power cable.
[0004] Cam assemblies are designed to yield efficient energy
transfer from the bow to the arrow. Some assemblies seek to achieve
a decrease in draw force closer to full draw and increase energy
stored by the bow at full draw for a given amount of rotation of
the cam assembly.
[0005] There exists a number of U.S. patents directed to compound
bows, including U.S. Pat. No. 7,305,979 issued to Craig Yehle on
Dec. 11, 2007. The Yehle patent discloses a cam assembly having a
journal for letting out a draw cable causing the cam to rotate and
two other journals for take-up mechanism and a let-out mechanism
for the two power cables. The Yehle patent requires that the power
cables and draw string each sit in a different components and
tracks for the take up and let out mechanism to work and to have
the efficiencies described therein.
[0006] Therefore, a compound bow having a mechanism with fewer
tracks is desired because of the advantage in assembly in
manufacturing and to increase efficiency in the transfer of energy
to propel bows.
[0007] Further, an adjustable or modular take-up/let-out mechanism
is desired to account for different size draw lengths or other
specifications required by the user.
SUMMARY OF THE INVENTION
[0008] The invention comprises, in one form thereof, a cam assembly
comprising bowstring cam component having a track for receiving a
bowstring; and a power cable cam component having a take up portion
and a let out portion, wherein the take up and let out portion have
a track for receiving a power cable.
[0009] More particularly, the invention includes a compound bow
comprising a handle portion; a limb portion; at least two cam
assemblies, each comprising a bowstring cam component having a
track for receiving a bowstring; and a power cable cam component
having a take up portion and a let out portion, wherein the take up
and let out portion have a track for receiving a power cable, a
draw stop pin, a take up terminating post, and a let out
terminating post; an axel; at least two power cables; and a
bowstring.
[0010] The cam assembly has a two track system wherein the power
cables utilize a track or opposing tracks made on the power cable
component of the cam assembly. Another track is formed on the
bowstring component of the cam assembly in which the bowstring
lies.
[0011] An advantage of the present invention is that the device has
high efficiency in transferring energy stored in the limbs during
the draw cycle to the arrow or other projectile of the device.
[0012] A further advantage of the present invention is that it
requires less component parts for cam assembly which is highly
desirable in the art.
[0013] An even further advantage of the present invention is that
the cam assembly allows for a modular format which allows the user
to change minor components to change parameters of the device (e.g.
draw length) without having to change the entire cam assembly or
bow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention is disclosed with reference to the
accompanying drawings, wherein:
[0015] FIG. 1 is a side view of a dual cam compound bow embodying
the present invention;
[0016] FIG. 2 is a side view of the top cam assembly in a first
embodiment of the present invention.
[0017] FIG. 3 is a rearview of the top cam assembly in a first
embodiment of the present invention.
[0018] FIG. 4 is a side view of the bottom cam assembly in a first
embodiment of the present invention.
[0019] FIG. 5 is a rearview of the bottom cam assembly in a first
embodiment of the present invention.
[0020] FIGS. 6 and 7 show the modular form of the let out portion
64a,b with the draw stop pin 90a,b attached thereto.
[0021] FIG. 8 is a side view of the top cam assembly in a second
embodiment of the present invention.
[0022] FIG. 9 is a side view of the bottom cam assembly in a second
embodiment of the present invention.
[0023] FIG. 10 is a side view of the top cam assembly in a third
embodiment of the present invention.
[0024] FIG. 11 is a side view of the bottom cam assembly in a third
embodiment of the present invention.
[0025] FIG. 12 is a rearview of the top cam assembly in a fourth
embodiment of the present invention.
[0026] FIG. 13 is a rearview of the bottom cam assembly in a first
embodiment of the present invention.
[0027] Corresponding reference characters indicate corresponding
parts throughout the several views. The examples set out herein
illustrate a few embodiments of the invention but should not be
construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION
[0028] FIG. 1 shows a dual cam compound bow 10 of the present
invention. The bow 10 has a frame, which includes bow limbs 12a,b
extending from handle 14. Extending from the handle is cable guard
16 and a cable slide 18 through which the power cables 50 and 52
are placed. The bowstring 70 and power cables 50, 52 are attached
to the bow 10 at the cam assemblies 30a,b, which further is placed
on the limbs via axel 36a,b. The cams 30a,b are shown in greater
detail in the following figures.
[0029] The cams 30a,b have bowstring assemblies 40a,b, each having
a single track for the bowstring 70 with each end of the bowstring
70 being attached to the cams 30a,b at a terminating post (not
shown). Further, the each of the cams 30a,b have terminating posts
80,82 for each of the ends of the respective power cables 50, 52,
and which will be described in more detail herein. Further, each
cam assembly 30a,b has a power cable assembly 60a,b having either a
single track or groove around perimeter of the assembly 60a,b for
receiving or retaining the power cables. Alternatively, the power
cable assembly 60a,b can have the tracks or grooves on the portions
of the assembly receiving the cable instead of a unitary track
around the perimeter. The power cable assembly 60a,b has a take up
portion 62a,b and a let out portion 64a,b for managing the take up
and let out of the power cables through a single track.
[0030] FIG. 2 shows a side view of the top cam assembly 30a. FIG. 2
shows one embodiment of the cam 30a in non-circular shape. The
bowstring 70 is in line with the track in the bowstring assembly
40a and attached with a terminating post (not shown). The power
cable assembly 60a has a take up portion 62a and a let out portion
64a, and can either be a unitary piece or be modular. For instance
as shown in FIG. 2, the power cable assembly 60a has a modular unit
for the let out portion 64a, which allows manufacturers to make a
single cam assembly with one small piece that can account for
varying sizes and preferences by the user. Specifically, this
versatility is important because each hunter or archer has
different specifications (e.g. draw length) which can be accounted
for by having a modular portion to the cam assembly 30a, and in
this case is the let out portion 64a. The power cable 52, in FIG.
2, is attached to terminating post 82a and wraps around the let out
portion 64a and therefore feeds power cable 52 out when the bow is
in full draw. On the opposing side of power cable assembly 60a is
power cable 50, which sits on the take up portion 62a of the
assembly 60a. Power cable 50 is attached at terminating post 80a,
and is taken up when the bow is in full draw by the take up portion
62a. The power cable assembly 60a is attached to the bowstring
assembly 30a by a fastening mechanism, but it will be well
recognized the power cable assembly 60a can be attached to the
bowstring assembly 40a by any means or, if desired, manufactured as
a single piece with the bowstring assembly 40a to make-up top cam
assembly 30a. As shown, the power cable assembly 60a is attached to
the bowstring assembly 40a by a fastener 78a. The cam assembly 30a
is attached to the limb 12a by axel 36a. Last the take power cable
assembly 60a, either in a unitary form or modular form, may
optionally have draw stop pin 90a attached to stop the draw cycle
of the bow. The draw stop pin 90a, however, does not have to be
attached to the power cable assembly 60a in order to function on
the cam assembly 30a.
[0031] FIG. 3 shows the rearview of the top cam assembly. As seen
from this perspective, the cam assembly 30a has one track on the
bowstring assembly 40a for the bowstring 70 and a second track for
the power cables 52 and 50 (not shown) on same track but on
opposing sides of the power cable assembly 60a. In FIG. 3, the let
out portion 64a is visible with power cable 52 sitting in the track
or groove. Axel 36a is inserted through the limb 12a and then the
cam assembly 30a and then the other end of the limb 12a.
[0032] FIG. 4 shows a side view of the bottom cam assembly 30b.
FIG. 4 shows the bottom cam 30b in non-circular shape as well. The
bowstring 70 is in bowstring assembly 40b and attached with a
terminating post (not shown). The power cable assembly 60b has a
take up portion 62b and a let out portion 64b, which can either be
a unitary piece or as shown can have a modular unit. In FIG. 4,
there is a modular assembly shown where the let up portion 64b can
be changed in size and shape according to the user's
specifications. The power cable 52, in FIG. 4, is attached to
terminating post 80b and wraps around the take up portion 62b and
therefore is taken up when the bow is in full draw. On the opposing
side of power cable assembly 60b is power cable 50, which attaches
to terminating post 82b and wraps around the let out portion 64b,
and is let out when the bow is in full draw position. The power cam
assembly 60b is attached to the bowstring assembly 30b by a
fastening mechanism, the two assemblies can be attached by any
means or if desired manufactured as a single piece. As shown, the
power cable assembly 60b is attached to the bowstring assembly 40b
by a fastener 78b. The cam assembly 30b is attached to the limb 12b
by axel 36b. Last the power cable assembly 60b, either in a unitary
or modular form, may optionally have draw stop pin 90b attached to
stop the draw cycle of the bow.
[0033] FIG. 5 shows the rearview of the bottom cam assembly 30b. As
seen from this perspective, the cam assembly 30b has a bowstring
assembly 40b for the bowstring 70, and a power cable assembly 60b
for both power cables 50,52. In FIG. 5, power cable 50 is visible
because it is sitting on the let out portion 64b of the power cable
assembly 60b. Axel 36b allows bottom cam assembly 30b to rotate
when the drawstring is pulled, and holds bottom cam assembly 30b in
limb 12b.
[0034] FIGS. 6 and 7 show the modular form of the let out portion
64a,b and draw stop pin 90a,b for the cam assemblies 30a,b. The let
out portion 64a,b and draw stop pins 90a,b can be attached in any
number of ways or can be further manufactured as a unitary piece.
Further, as described above, let out portion 64a,b can be
manufactured as a single part of power cable assembly 60a,b.
Therefore, though the modular form is more desirable to personalize
the parameters of the device size (e.g. draw length), the cam
assembly could be manufactured as a single unit or in varying
degrees of pieces.
[0035] FIGS. 8 and 9 show a side view of a second embodiment of the
present invention 100a,b. FIG. 8 shows the top cam assembly 100a is
in a circular shape. In particular, the power cable assembly 120a
is shown as being in a unitary form, having the take up portion
122a and let out portion 124a. The draw stop pin 90a is not
attached to the power cable assembly 120a, though if preferred the
assembly 120a could be attached to the pin 90a. Further the
bowstring assembly 110a is also in a circular or disc shape with
power cable assembly 120a attached thereto. FIG. 9 exemplifies the
bottom cam assembly 100b for the second embodiment, which is in a
circular or disc shape. Generally the other components of the cam
assemblies 100a,b are similar to those shown in the first
embodiment.
[0036] FIGS. 10 and 11 show a third embodiment of the present
invention, wherein the cam assembly 200a,b have a circular portion
for the bowstring track 110a,b and a non-circular power cable
assembly 60a,b. It will be understood that other embodiments could
include a non-circular portion for the bowstring assembly and a
circular power cable assembly and, again, can be either modular or
unitary form. Further other geometrical shapes, such as ovular, may
be used in varying forms for either the bowstring or power cable
assembly.
[0037] Still another embodiment could include a three track system,
as shown in the rearview perspectives of FIGS. 12 and 13. The three
track system would be used where there are four power cables. This
type of embodiment would include two power cable assemblies as
described above, both of which would be attached to the bowstring
assembly.
[0038] In use, using the first embodiments as an exemplar and in
reference to FIGS. 1-3, the bowstring 70 is pulled rearward toward
the hunter or archer. The tension by the bowstring forces the cam
assemblies 30a,b to rotate rearward. Focusing on FIG. 1, the power
cable assembly 60a on top cam assembly 30a is moved upward as the
entire cam 30a is moved rearward. The terminating post 80, with
power cable 50 attached, moves upward, and therefore causes take up
of power cable 50. On the bottom cam assembly 30b the cam 30b is
also moved rearwardly. The positioning of the power cable assembly
60 and power cable 50 causes power cable 50 to be let out on the
bottom cam assembly 30a. The same is true in the opposite manner
for power cable 52 (i.e. power cable 52 is taken up) on the cam
assemblies 30a,b. Accordingly energy is stored in the limbs of the
device and transferred to the arrow or other projectile placed in
the compound bow in a highly efficient manner with little shock to
the user.
[0039] Though the compound bow embodying the invention may have
differing specifications, the bow may have a brace height of about
eight (8) inches and axel-to-axel length of about thirty-two and
half (321/2) inches. The draw length can range from twenty-seven
(27) to thirty (30) inches and a draw weight between sixty (60) to
eighty (80) inches.
[0040] It should be particularly noted that dual track cam
disclosed in this invention has a highly efficient and powerful
performance. With respect to speed, the following performance
results were noted in a twenty-nine (29'') inch draw cycle, sixty
pound (60 lbs.) draw weight compound bow, in testing completed by
Archery Evolution:
TABLE-US-00001 Arrow (Grains) 300 360 420 540 Speed (ft./sec.)
307.3 283.5 264.2 235.4 Kinetic Energy (ft. lbs.) 62.9 64.2 65.1
66.4 Momentum 13.2 14.6 15.9 18.2 Dynamic Efficiency 83.7% 85.5%
86.7% 88.5% Noise Output (dBA) 88.7 84.1 85.5 87.1 Total Vibration
(G) 222.8 234.4 228.7 188.6
[0041] While the invention has been described with reference to
particular embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the scope of the invention.
[0042] Therefore, it is intended that the invention not be limited
to the particular embodiments disclosed as the best mode
contemplated for carrying out this invention, but that the
invention will include all embodiments falling within the scope and
spirit of the appended claims.
* * * * *