U.S. patent application number 16/237062 was filed with the patent office on 2019-05-09 for crossbow with pulleys that rotate around stationary axes.
The applicant listed for this patent is Ravin Crossbows, LLC. Invention is credited to Craig Thomas Yehle.
Application Number | 20190137212 16/237062 |
Document ID | / |
Family ID | 61191530 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190137212 |
Kind Code |
A1 |
Yehle; Craig Thomas |
May 9, 2019 |
Crossbow with Pulleys that Rotate Around Stationary Axes
Abstract
A crossbow including a frame with a riser and a center trail.
First and second flexible limbs are attached to the riser. A draw
string is received in string guide journals in first and second
cams rotatably attached to the frame. The draw string unwinds from
the string guide journals as it translates between a released
configuration and a drawn configuration. The first and second cams
include at least first and second power cable take-up journals,
respectively. At least first and second power cables are attached
to the first and second limbs and received in the first and second
power cable take-up journals, respectively. As the crossbow is
drawn from the released configuration to the drawn configuration
the first and second power cables wrap onto the respective first
and second power cable take-up journals.
Inventors: |
Yehle; Craig Thomas;
(Winona, MN) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Ravin Crossbows, LLC |
Superior |
WI |
US |
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|
Family ID: |
61191530 |
Appl. No.: |
16/237062 |
Filed: |
December 31, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15782259 |
Oct 12, 2017 |
10209026 |
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16237062 |
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15433769 |
Feb 15, 2017 |
10126088 |
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15782259 |
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15294993 |
Oct 17, 2016 |
9879936 |
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15433769 |
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15098537 |
Apr 14, 2016 |
9494379 |
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15294993 |
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14107058 |
Dec 16, 2013 |
9354015 |
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15098537 |
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62244932 |
Oct 22, 2015 |
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62441618 |
Jan 3, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41B 5/123 20130101;
F41B 5/1411 20130101; F41B 5/066 20130101; F41B 5/10 20130101; F41B
5/143 20130101; F41B 5/1469 20130101; F41B 5/105 20130101 |
International
Class: |
F41B 5/10 20060101
F41B005/10; F41B 5/12 20060101 F41B005/12; F41B 5/14 20060101
F41B005/14; F41B 5/06 20060101 F41B005/06 |
Claims
1. A crossbow comprising: a frame comprising a center rail; first
and second flexible limbs attached to the frame; a first cam
assembly mounted to the frame and rotatable around a first axis
located a fixed distance from the center rail, the first cam
assembly comprising a first draw string journal having a first
plane of rotation perpendicular to the first axis, and a first
power cable take-up journal comprising a path that is not co-planar
with the first plane of rotation; a second cam assembly mounted to
the frame and rotatable around a second axis located a fixed
distance from the center rail, the second cam assembly comprising a
second draw string journal having a second plane of rotation
perpendicular to the second axis, and a second power cable take-up
journal comprising a path that is not co-planar with the second
plane of rotation; a draw string received in the draw string
journals with the draw string adjacent a clown-range side when in a
released configuration and secured to the first and second cam
assemblies, wherein the draw string unwinds from the draw string
journals as it translates from a released configuration to a drawn
configuration, wherein a separation between the first axis and the
second axis is fixed at about 3 inches to about 8 inches and the
draw string in the drawn configuration comprises an included angle
of less than about 25 degrees; and first and second power cables
having first ends operatively coupled to the first and second cam
assemblies and received in the first and second power cable take-up
journals, and second ends operatively coupled to the first and
second flexible limbs, respectively; wherein the first and second
power cables wrap at least 270 degrees around the respective first
and second power cable take-up journals as the drawstring is moved
between the released configuration to the drawn configuration, and
the first and second cables unwrap at least 270 degrees from the
respective first and second power cable take-up journals as the
drawstring is moved between the drawn configuration to the released
configuration.
2. The crossbow of claim 1 wherein the first and second cam
assemblies are mounted to a riser attached to the center rail.
3. The crossbow of claim 1 wherein a draw weight on the draw string
increases continuously as the crossbow is drawn from the released
configuration to the drawn configuration.
4. The crossbow of claim 1 wherein the first and second power cable
take-up journals displace the first and second power cables along
the first and second axes relative to the first and second planes
of rotation, respectively, as the drawstring is moved between the
released configuration to the drawn configuration.
5. The crossbow of claim 1 wherein the draw string translates from
the release configuration to the drawn configuration comprising a
power stroke of about 10 inches to about 15 inches.
6. The crossbow of claim 1 wherein the first and second cam
assemblies rotate between about 300 degrees to about 360 degrees
when the crossbow is drawn from the released configuration to the
drawn configuration.
7. The crossbow of claim 1 wherein the first and second power cable
take-up journals comprise helical power cable take-up journals.
8. The crossbow of, claim 1 wherein the first and second power
cable take-up journals comprise a width at least twice a width of
the first and second of power cables.
9. The crossbow of claim 1 wherein the first and second power cable
take-up journals each comprise first and second upper and lower
power cable take-up journals on opposite sides of the first and
second draw string journals, respectively, and the first and second
power cables comprise a pair of first and a pair of second power
cables.
10. The crossbow of claim 1 wherein the draw string in the drawn
configuration comprises an included angle of less than about 15
degrees.
11. The crossbow of claim 1 wherein limb tips of the first and
second flexible limbs overlap the first and second cam assemblies
when the crossbow is in the drawn configuration.
12. The crossbow of claim 1 comprising: a string carrier captured
by the center rail that slides forward to engage with the draw
string in the released configuration and slides rearward to a
retracted position that locates the draw string in the drawn
configuration, the string carrier comprising a catch movable
between a closed position that engages the draw string and an open
position that releases the draw string, a sear moveable between a
cocked position coupled with the catch to retain the catch in the
closed position and a de-cocked position that release the catch to
the open position, and a safety moveable between a free position
and a safe position that prevents the catch from moving to the open
position; and a trigger mounted to the center rail that selectively
moves the catch from the closed position to the open position that
releases the draw string from the string carrier while the string
carrier is in the retracted position.
13. The crossbow of claim 12 comprising: a cocking mechanisms with
a rotating member coupled to a flexible tension member attached to
the string carrier; and a cocking handle configured to rotate the
rotating member to move the string carrier to the retracted
position.
14. The crossbow of claim 13 comprising a torque control mechanism
with an integral clutch that limits output torque applied to the
rotating member by the cocking handle such that rotating the
cocking handle after the string carrier is in the retracted
position causes the cocking handle to slip to limit torque applied
to the cocking mechanism.
15. The crossbow of claim 12 comprising: at least one cocking rope
configured to releasably engage with the string carrier to retract
the string carrier and the draw string to the drawn configuration;
and a retaining mechanism that releasably retains the string
carrier in the retracted position and the draw string in the drawn
configuration.
16. A crossbow comprising: a frame comprising a center rail; first
and second flexible limbs attached to the frame; a first cam
assembly mounted to the frame and rotatable around a first axis
located a fixed distance from the center rail, the first cam
assembly comprising a first draw string journal having a first
plane of rotation perpendicular to the first axis, and a first
helical power cable take-up journal comprising a path that is not
co-planar with the first plane of rotation; a second cam assembly
mounted to the frame and rotatable around a second axis located a
fixed distance from the center rail, the second cam assembly
comprising a second draw string journal having a second plane of
rotation perpendicular to the second axis, and a second helical
power cable take-up journal comprising a path that is not co-planar
with the second plane of rotation; a draw string received in the
draw string journals in a reverse draw configuration with the draw
string adjacent a down-range side when in a released configuration
and secured to the first and second cam assemblies, wherein the
draw string unwinds from the draw string journals as it translates
from a released configuration to a drawn configuration, wherein a
separation between the first axis and the second axis is about 3
inches to about 8 inches and the draw string in the drawn
configuration comprises an included angle of less than about 25
degrees; and first and second power cables having first ends
received in the first and second helical power cable take-up
journals, and second ends operatively coupled to the first and
second flexible limbs, respectively; wherein the first and second
helical power cable take-up journals displace the first and second
power cables along the first and second axes relative to the first
and second planes of rotation, respectively, and the first and
second power cables wrap at least 270 degrees around the respective
first and second helical power cable take-up journals as the
drawstring is moved between the released configuration to the drawn
configuration, and the first and second power cables unwrap at
least 270 degrees from the respective first and second helical
power cable take-up journals as the drawstring is moved between the
drawn configuration to the released configuration.
17. A method of operating a crossbow comprising the steps of:
locating a draw string in first and second draw string journals on
first and second cam assemblies, the first and second cam
assemblies having first and second planes of rotation that are
perpendicular to first and second axes of rotation located a fixed
distance from the frame, respectively, and first and second helical
power cable take-up journal comprising paths that are not co-planar
with the first and second planes of rotation; translating the draw
string from a released configuration to a drawn configuration so
the draw string unwinds from the draw string journals as the first
and second cam assemblies rotate around the first and second axes,
wherein a separation between the first axis and the second axis is
about 3 inches to about 8 inches and the draw string in the drawn
configuration comprises an included angle of less than about 15
degrees; wrapping the first and second power cables more than 270
degrees onto the first and second helical power cable take-up
journals as the draw string translates from the released
configuration to the drawn configuration, the first and second
power cables having first ends operatively coupled to the first and
second cam assemblies and second ends operatively coupled to the
first and second flexible limbs, respectively; displacing the first
and second power cables along the first and second axes relative
the first and second planes of rotation of the first and second
draw string journals as the bow string is translated from the
released configuration to the drawn configuration; and unwrapping
the first and second power cables more than 270 degrees from first
and second helical power cable take-up journals as the draw string
translates from the drawn configuration to the released
configuration.
18. The method of claim 17 comprising the steps of: sliding a
string carrier captured by the center rail forward and into engage
with the draw string in the released configuration; moving a catch
on the string carrier to a closed position that engaged the draw
string; sliding the string carrier to a retracted position that
locates the draw string in the drawn configuration; and engaging a
trigger mounted to the center rail with the catch when the string
carrier is in the retracted position to move the catch from the
closed position to an open position that releases the draw string
from the string carrier.
19. The method of claim 18 comprising rotating a cocking handle
engaged with a cocking mechanism to retract the draw string to the
drawn configuration.
20. The method of claim 19 comprising activating a torque control
mechanism in the cocking handle to limit torque applied to the
cocking mechanism.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application is also a continuation of U.S.
patent Ser. No. 15/782,259, entitled Crossbow with Pulleys that
Rotate Around Stationary Axes, filed Oct. 12, 2017, which claims
the benefit of U.S. Provisional Application Ser. No. 62/441,618,
entitled Crossbow with Pulleys that Rotate Around Stationary Axes,
filed Jan. 3, 2017.
[0002] The present application is also a continuation of U.S.
patent Ser. No. 15/782,259, entitled Crossbow with Pulleys that
Rotate Around Stationary Axes, filed Oct. 12, 2017, which is a
continuation-in-part of patent Ser. No. 15/443,769 entitled
Crossbow, filed Feb. 15, 2017, which is a continuation-in-part of
U.S. patent Ser. No. 15/294,993 entitled String Guide for a Bow,
filed Oct. 17, 2016, which is a continuation-in-part of U.S. patent
Ser. No. 15/098,537 entitled Crossbow, filed Apr. 14, 2016 (issued
as U.S. Pat. No. 9,494,379), which claims the benefit of U.S.
Provisional Application Ser. No. 62/244,932, filed Oct. 22, 2015
and is also a continuation-in-part of U.S. patent Ser. No.
14/107,058 entitled String Guide System for a Bow, filed Dec. 16,
2013 (issued as U.S. Pat. No. 9,354,015), the entire disclosures of
which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0003] The present disclosure is directed to a crossbow with
pulleys that rotate around stationary axes that are fixed relative
to the center rail and the riser. Power cables connect the limbs to
the pulleys such that as the crossbow is drawn from the released
configuration to the drawn configuration the power cables wrap onto
the respective power cable take-up journals. Only the draw string
crosses the center rail.
BACKGROUND OF THE INVENTION
[0004] Bows have been used for many years as a weapon for hunting
and target shooting. More advanced bows include cams that increase
the mechanical advantage associated with the draw of the bowstring.
The cams arc configured to yield a decrease in draw force near full
draw. Such cams preferably use power cables that load the bow
limbs. Power cables can also be used to synchronize rotation of the
cams, such as disclosed in U.S. Pat. No. 7,305,979 (Yehle).
[0005] With conventional bows and crossbows the draw string is
typically pulled away from the generally concave area between the
limbs and away from the riser and limbs. This design limits the
power stroke for bows and crossbows.
[0006] In order to increase the power stroke, the draw string can
be positioned on the down-range side of the string guides so that
the draw string unrolls between the string guides toward the user
as the bow as the bow is drawn, such as illustrated in U.S. Pat.
Nos. 7,836,871 (Kempf) and 7,328,693 (Kempf). One drawback of this
configuration is that the power cables can limit the rotation of
the cams to about 270 degrees. In order to increase the length of
the power stroke, the diameter of the pulleys needs to be
increased. Increasing the size of the pulleys results in a larger
and less usable bow.
[0007] FIGS. 1-3 illustrate a string guide system for a bow that
includes power cables 20A, 20B ("20") attached to respective string
guides 22A, 22B ("22") at first attachment points 24A, 24B ("24").
The second ends 26A, 26B ("26") of the power cables 20 are attached
to the axles 28A, 28B ("28") of the opposite string guides 22. Draw
string 30 engages down-range edges 46A, 46B of string guides 22 and
is attached at draw string attachment points 44A, 44B ("44")
[0008] As the draw string 30 is moved from released configuration
32 of FIG. 1 to drawn configuration 34 of FIGS. 2 and 3, the string
guides 22 counter-rotate toward each other about 270 degrees. The
draw string 30 unwinds between the string guides 22 from opposing
cam journals 48A, 48B ("48") in what is referred to as a reverse
draw configuration. As the first attachment points 24 rotate in
direction 36, the power cables 20 are wrapped around respective
power cable take-up journal, of the string guides 22, which in turn
bends the limbs toward each other to store the energy needed for
the bow to fire the arrow.
[0009] Further rotation of the string guides 22 in the direction 36
causes the power cables 20 to contact the power cable take-up
journal, stopping rotation of the cam. The first attachment points
24 may also contact the power cables 20 at the locations 38A, 38B
("38"), preventing further rotation in the direction 36. As a
result, rotation of the string guides 22 is limited to about 270
degrees, reducing the length 40 of the power stroke.
BRIEF SUMMARY OF THE INVENTION
[0010] The present disclosure is directed to a crossbow with
pulleys rotatably attached to the center rail or the riser. Power
cables connect the limbs to the pulleys such that only the draw
string translates between a released configuration and a drawn
configuration the power cables wrap onto power cable take-up
journals on the pulleys.
[0011] In one embodiment the crossbow includes a frame with a riser
and a center rail. First and second, flexible limbs are attached to
the riser. A draw string is received in string guide journals in
first and second cams rotatably attached to the frame. The draw
string unwinds from the string guide journals as it translates
between a released configuration and a drawn configuration. The
first and second cams include at least first and second power cable
take-up journals, respectively. At least first and second power
cables are attached to the first and second limbs and received in
the first and second power cable take-up journals, respectively. As
the crossbow is drawn from the released configuration to the drawn
configuration the first and second power cables wrap onto the
respective first and second power cable take-up journals.
[0012] The first and second cams can be mounted to the riser or the
center rail. The first and second axes around which the first and
second cams rotate are stationary with respect to the frame. The
separation between first and second axes is preferably less than
about 5 inches, and more preferably less than about 4 inches.
[0013] The first and second cams preferably rotate between about
270 degrees to about 330 degrees when the crossbow is drawn from
the released configuration to the drawn configuration. In another
embodiment, the first and second cams rotate between about 300
degrees to about 360 degrees when the crossbow is drawn from the
released configuration to the drawn configuration. In yet another
embodiment, the first and second cams rotate more than about 360
degrees when the crossbow is drawn from the released configuration
to the drawn configuration. The first and second power cables do
not cross over the center rail. The draw string in the drawn
configuration preferably has an included angle of less than about
15 degrees.
[0014] In one embodiment, the crossbow includes a string carrier
that slides along the center rail to engage with the draw string in
the released configuration and to a retracted position that locates
the draw string in the drawn configuration. A retaining mechanism
retains the string carrier in the retracted position and the draw
string in the drawn configuration. A trigger releases the draw
string from the string carrier to fire the crossbow when the string
carrier is in the retracted position.
[0015] In one embodiment, the string carrier is captured by the
center rail during movement of the string carrier between the
release configuration and the drawn configuration. The string
carrier is preferably constrained to move in a single degree of
freedom along the center rail between the release configuration and
the drawn configuration. In one embodiment, the retaining mechanism
is a cocking mechanism that moves the string carrier along the
center rail to the retracted position and the draw string to the
drawn configuration. In another embodiment, at least one cocking
rope configured to engage with the string carrier is used to
retract the string carrier and the draw string to the drawn
configuration.
[0016] The present disclosure is also directed to a crossbow
including a frame with a riser and a center rail. First and second
flexible limbs are attached to the riser. A first cam is mounted to
the frame and is rotatable around a first axis. The first cam
includes a first draw string journal having a first plane of
rotation perpendicular to the first axis, and at least one first
power cable take-up journal. A second cam is mounted to the frame
and is rotatable around a second axis. The second cam includes a
second draw string journal having a second plane of rotation
perpendicular to the second axis, and at least one second power
cable take-up journal. A draw string is received in the first and
second string guide journals and secured to the first and second
cams. The draw string unwinds from the first and second string
guide journals as it translates from a released configuration to a
drawn configuration. At least first and second power cables are
attached to the first and second limbs and received in the first
and second power cable take-up journals, respectively. As the
crossbow is drawn from the released configuration to the drawn
configuration the first and second power cables wrap, onto the
respective first and second power cable take-up journals.
[0017] The present disclosure is also directed to a crossbow
including a frame with a riser and a center rail. First and second
flexible limbs are attached to the riser. A first cam is mounted to
the frame and is rotatable around a first axis. The first cam
includes a first draw string journal having a first plane of
rotation perpendicular to the first axis, a first upper power cable
take-up journal extending in a direction perpendicular to the first
plane of rotation of the first draw string journal, and a first
lower power cable take-up journal extending in an opposite
direction perpendicular to the first plane of rotation. A second
cam is mounted to the frame and is rotatable around a second axis.
The second cam includes a second draw string journal having a
second plane of rotation perpendicular to the second axis, a second
upper power cable take-up journal extending in a direction
perpendicular to the second plane of rotation of the second draw
string journal, and a second lower power cable take-up journal
extending in an opposite direction perpendicular to the second
plane of rotation. A draw string is received in the first and
second string guide journals and secured to the first and second
cams. The draw string unwinds from the first and second string
guide journals as it translates from a released configuration to a
drawn configuration. First upper and lower power cables are
attached to the first limb and received in the upper and lower
power cable take-up journals on the first cam. Second upper and
lower power cables are attached to, the second limb and received in
the upper and lower power cable, take-up journals on the second
cam. The first and second power cables do not cross over the center
rail.
[0018] In one embodiment, as the crossbow is drawn from the
released configuration to the drawn configuration the upper and
lower power cables wrap onto the respective upper and lower power
cable take-up journals and are displaced along the first and second
axes away from the first and second planes of rotation of the first
and second draw string journals.
[0019] The present disclosure is also directed to a method of
assembling a crossbow. The method includes providing a frame with a
riser and a center rail. At least first and second flexible limbs
are attached to the riser. A draw string is located in string guide
journals on first and second cams rotatable attached to the frame,
such that the draw string unwinds from the string guide journals as
it translates between a released configuration and a drawn
configuration. At least first and second power cables are attached
to the first and second, limbs and the first and second cams,
respectively, such that as the crossbow is drawn from the released
configuration to the drawn configuration the first and second power
cables wrap onto first and second power cable take-up journals on
the first and second cams, respectively.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0020] FIG. 1 is a bottom view of a prior art string guide system
for a bow in a released configuration.
[0021] FIG. 2 is a bottom view of the string guide system of FIG. 1
in a drawn configuration.
[0022] FIG. 3 is a perspective view of the string guide system of
FIG. 1 in a drawn configuration.
[0023] FIG. 4 is a bottom view of a string guide system for a bow
with a helical take-up journal in accordance with an embodiment of
the present disclosure.
[0024] FIG. 5 is a bottom view of the string guide system of FIG. 4
in a drawn configuration.
[0025] FIG. 6 is a perspective view of the string guide system of
FIG. 4 in a drawn configuration.
[0026] FIG. 7 is an enlarged view of the left string guide of the
string guide system of FIG. 4.
[0027] FIG. 8 is an enlarged view of the right string guide of the
string guide system of FIG. 4.
[0028] FIG. 9A is an enlarged view of a power cable take-up journal
sized to receive two full wraps of the power cable in accordance
with an embodiment of the present disclosure.
[0029] FIG. 9B is an enlarged view of a power cable take-up journal
and draw string journal sized to receive two full wraps of the
power cable and draw string in accordance with an embodiment of the
present disclosure.
[0030] FIG. 9C is an enlarged view of an elongated power cable
take-up journal in accordance with an embodiment of the present
disclosure.
[0031] FIG. 10 is a schematic illustration of a bow with a string
guide system in accordance with an embodiment of the present
disclosure.
[0032] FIG. 11 is a schematic illustration of an alternate bow with
a string guide system in accordance with an embodiment of the
present disclosure.
[0033] FIG. 12 is a schematic illustration of an alternate dual-cam
bow with a string guide system in accordance with an embodiment of
the present disclosure.
[0034] FIGS. 13A and 13B are top and side views of a crossbow with
helical power cable journals in accordance with an embodiment of
the present disclosure.
[0035] FIG. 14A is an enlarged top view of the crossbow of FIG.
13A.
[0036] FIG. 14B is an enlarged bottom view of the crossbow of FIG.
13A.
[0037] FIG. 14C illustrates an arrow rest in accordance with an
embodiment of the present disclosure.
[0038] FIG. 14D and 14E illustrate the cocking handle for the
crossbow of FIG. 13A.
[0039] FIGS. 14F and 14G illustrate the quiver for the crossbow of
FIG. 13A.
[0040] FIG. 15 is a front view of the crossbow of FIG. 13A.
[0041] FIGS. 16A and 16B are top and bottom views of cams with
helical power cable journals in accordance with an embodiment of
the present disclosure.
[0042] FIGS. 17A and 17B are opposite side view of a trigger
assembly in accordance with an embodiment of the present
disclosure.
[0043] FIG. 17C is a side view of the trigger of FIG. 17A with a
bolt engaged with the draw string in accordance with an embodiment
of the present disclosure.
[0044] FIG. 17D is a perspective view of a low friction interface
at a rear edge of a string catch in accordance with an embodiment
of the present disclosure.
[0045] FIGS. 18A and 18B illustrate operation of the trigger
mechanism in accordance with an embodiment of the present
disclosure.
[0046] FIGS. 19 and 20 illustrate a cocking mechanism for a
crossbow in accordance with an embodiment of the present
disclosure.
[0047] FIGS. 21A and 21B illustrate a crossbow in a release
configuration in accordance with an embodiment of the present
disclosure.
[0048] FIGS. 22A and 22B illustrate the cams of the crossbow of
FIGS. 21A and 21B in the release configuration.
[0049] FIGS. 23A and 23B illustrate the crossbow of FIGS. 21A and
21B in a drawn configuration in accordance with an embodiment of
the present disclosure.
[0050] FIGS. 24A, 24B, and 24C illustrate the cams of the crossbow
of FIGS. 23A and 23B in the drawn configuration.
[0051] FIGS. 25A and 25B illustrate an alternate trigger assembly
in accordance with an embodiment of the present disclosure.
[0052] FIG. 25C is a front view of an alternate string carrier for
the crossbow in accordance with an embodiment of the present
disclosure.
[0053] FIGS. 26A and 26B illustrate an alternate cocking handle in
accordance with an embodiment of the present disclosure.
[0054] FIGS. 27A-27D illustrate an alternate tunable arrow rest for
a crossbow n accordance with an embodiment of the present
disclosure.
[0055] FIGS. 28A-28F illustrate alternate cocking systems for a
crossbow in accordance with an embodiment of the present
disclosure.
[0056] FIG. 29 illustrates capture of the string carrier in the
center rail illustrated in FIG. 13B.
[0057] FIGS. 30A through 30C illustrate an alternate crossbow in
which the pulleys rotate around axes in a fixed relationship
relative to the center rail and the riser in accordance with an
embodiment of the present disclosure.
[0058] FIGS. 31A through 31C illustrate a variation of the crossbow
of FIG. 30A with limbs swept forward in accordance with an
embedment of the present disclosure.
[0059] FIG. 32 illustrates an alternate crossbow in which the
pulleys rotate around axes attached to the riser in accordance with
an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0060] FIG. 4 illustrates a string guide system 90 for a bow with a
reverse draw configuration 92 in accordance with an embodiment of
the present disclosure. Power cables 102A, 102B ("102") are
attached to respective string guides 104A, 104B ("104") at first
attachment points 106A, 106B ("106"). Second ends 108A, 108B
("108") of the power cables 102 are attached to axles 110A, 110B
("110") of the opposite string guides 104. In the illustrated
embodiment, the power cables 102 wrap around power cable take-ups
112A, 112B ("112") located on the respective cam assembles 104 when
in the released configuration 116 of FIG. 4.
[0061] In the reverse draw configuration 92 the draw string 114 is
located adjacent down-range side 94 of the string guide system 70
when in the released configuration 116. In the released
configuration 116 of FIG. 4, the distance between the axles 110 may
be in the range of less than about 16 inches to less than about 10
inches. In the drawn configuration 118, the distance between the
axles 110 may be in the range of about between about 6 inches to
about 8 inches, and more preferably about 4 inches to about 8
inches. In one embodiment, the distance between the axles 110 in
the drawn configuration 118 is less than about 6 inches, and
alternatively, less than about 4 inches.
[0062] As illustrated in FIGS. 5 and 6, the draw string 114
translates from the down-range side 94 toward the up-range side 96
and unwinds between the first and second string guides 104 in a
drawn configuration 118. In the illustrated embodiment, the string
guides 104 counter-rotate toward each other in directions 120 more
than 360 degrees as the draw string 114 unwinds between the string
guides 104 from opposing cam journals 130A, 130B ("130").
[0063] The string guides 104 each include one or more grooves,
channels or journals located between two flanges around at least a
portion of its circumference that guides a flexible member, such as
a rope, string, belt, chain, and the like. The string guides can be
cams or pulleys with a variety of round and non-round shapes. The
axis of rotation can be located concentrically or eccentrically
relative to the string guides. The power cables and draw strings
can be any elongated flexible member, such as woven and non-woven
filaments of synthetic or natural materials, cables, belts, chains,
and the like.
[0064] As the first attachment points 106 rotate in direction 120,
the power cables 102 are wrapped onto cams 126A, 126B ("126") with
helical journals 122A, 122B ("122"), preferably located at the
respective axles 110. The helical journals 122 take up excess slack
in the power cables 102 resulting from the string guides 104 moving
toward each other in direction 124 as the axles 110 move toward
each other.
[0065] The helical journals 122 serve to displace the power cables
102 away from the string guides 104, so the first attachment points
106 do not contact the power cables 102 while the bow is being
drawn (see FIGS. 7 and 8). As a result, rotation of the string
guides 104 is limited only by the length of the draw string
journals 130A, 103B ("130"). For example, the draw string journals
130 can also be helically in nature, wrapping around the axles 110
ore than 360 degrees.
[0066] As a result, the power stroke 132 is extended. In the
illustrated embodiment, the power stroke 132 can be increased by at
least 25%, and preferably by 40% or more, without changing the
diameter of the string guides 104. The power stroke 132 can be in
the range of about 8 inches to about 20 inches. The present
disclosure permits crossbows that generate kinetic energy of
greater than 70 ft.-lbs. of energy with a power stroke of about 8
inches to about 15 inches. In another embodiment, the present
disclosure permits a crossbow that generates kinetic energy of
greater than 125 ft.-lbs. of energy with a power stroke of about 10
inches to about 15 inches.
[0067] In some embodiments, the geometric profiles of the draw
string journals 130 and the helical journals 122 contribute to
let-off at full draw. A more detailed discussion of cams suitable
for use in bows is provided in U.S. Pat. No. 7,305,979 (Yehle),
which is hereby incorporated by reference.
[0068] FIGS. 7 and 8 are enlarged views of the string guides 104A,
104B, respectively, with the draw string 114 in the drawn
configuration 118. The helical journals 122 have a length
corresponding generally to one full wrap of the power cables 102.
The axes of rotation 146A, 146B ("146") of the first and second
helical journals 122 preferably extend generally perpendicular to a
plane of rotation of the first and second string guides 104. The
helical journals 122 displace the power cables 102 away from the
draw string 114 as the bow is drawn from the released configuration
116 to the drawn configuration 118. Height 140 of the helical
journals 122 raises the power cables 102 above top surface 142 of
the string guides 104. The resulting gap 144 permits the first
attachment points 106 and the power cable take-ups 112 to pass
freely under the power cables 102. The length of the helical
journals 122 can be increased or decreased to optimize draw force
versus draw distance for the bow and let-off The axes of rotation
146 of the helical journals 122 are preferably co-linear with axes
110 of rotation for the string guides 104.
[0069] FIG. 9A illustrates an alternate string guide 200 in
accordance with an embodiment of the present disclosure. Power
cable take-ups 202 have helical journals 204 that permit the power
cables 102 to wrap around about two full turns or about 720
degrees. The extended power cable take-up 202 increases the gap 206
between the power cables 102 and top surface 208 of the string
guide 200 and provides excess capacity to accommodate more than 360
degrees of rotation of the string guides 200.
[0070] FIG. 9B illustrates an alternate string guide 250 in
accordance with an embodiment of the present disclosure. The draw
string journals 252 and the power cable journals 254 are both
helical structures designed so that the draw string 114 and the
power cables 102 can wrap two full turns around the string guide
250.
[0071] FIG. 9C illustrates an alternate string guide 270 with a
smooth power cable take-up 272 in accordance with an embodiment of
the present disclosure. The power cable take-up 272 has a surface
274 with a height 276 at least twice a diameter 278 of the power
cable 102. In another embodiment, the surface 274 has a height 276
at least three times the diameter 278 of the power cable 102.
Biasing force 280, such as from a cable guard located on the bow
shifts the power cables 102 along the surface 274 away from top
surface 282 of the string guide 270 when in the drawn configuration
284.
[0072] FIG. 10 is a schematic illustration of bow 150 with a string
guide system 152 in accordance with an embodiment of the present
disclosure. Bow limbs 154A, 154B ("154") extend oppositely from
riser 156. String guides 158A, 158B ("158") are rotatably mounted,
typically eccentrically, on respective limbs 154A, 154B on
respective axles 160A, 160B ("160") in a reverse draw configuration
174.
[0073] Draw string 162 is received in respective draw string
journals (see e.g., FIGS. 7 and 8) and secured at each end to the
string guides 158 at locations 164A, 164B. When the bow is in the
released configuration 176 illustrated in FIG. 10, the draw string
162 is located adjacent the down-range side 178 of the bow 150.
When the bow 150 is drawn, the draw string 162 unwinds from the
draw string journals toward the up-range side 180 of the bow 150,
thereby rotating the string guides 158 in direction 166.
[0074] First power cable 168A is secured to the first string guide
158A at first attachment point 170A and engages with a power cable
take-up with a helical journal 172A (see FIGS. 7 and 8) as the bow
150 is drawn. As the string guide 158A rotates in the direction
166, the power cable 168A is taken up by the cam 172A. The other
end of the first power cable 168A is secured to the axle 160B.
[0075] Second power cable 168B is secured to the second string
guide 158B at first attachment point 170B and engages with a power
cable take-up with a helical journal 172B (see FIGS. 7 and 8) as
the bow 150 is drawn. As the string guide 158B rotates, the power
cable 168B is taken up by the cam 172B. The other end of the second
power cable 168B is secured to the axle 160A. Alternatively, the
other ends of the first and second power cables 168 can be attached
to the riser 156 or an extension thereof, such as the pylons 32
illustrated in commonly assigned U.S. Pat. Nos. 8,899,217 (Islas)
and 8,651,095 (Islas), which are hereby incorporated by reference.
Any of the power cable configurations illustrated herein can be
used with the bow 1.50 illustrated in FIG. 10. The power cable
take-ups 172 are arranged so that as the bow 150 is drawn, the bow
limbs 154 are drawn toward one another.
[0076] FIG. 11 is a schematic illustration of a crossbow 300 with a
reverse draw configuration 302 in accordance with an embodiment of
the present disclosure. The crossbow 300 includes a center portion
304 with down-range side 306 and up-range side 308. In the
illustrated embodiment, the center portion 304 includes riser 310.
First and second flexible limbs 312A, 312B ("312") are attached to
the riser 310 and extend from opposite sides of the center portion
304.
[0077] Draw string 314 extends between first and second string
guides 316A, 316B ("316"). In the illustrated embodiment, the
string guide 316A is substantially as shown in FIGS. 4-8, while the
string guide 316B is a conventional pulley.
[0078] The first string guide 316A is mounted to the first bow limb
312A and is rotatable around a first axis 318A. The first string
guide 316A includes a first draw string journal 320A and a first
power cable take-up journal 322A, both of which are oriented
generally perpendicular to the first axis 318A. (See e.g., FIG. 8).
The first power cable take-up journal 322A includes a width
measured along the first axis 318A that is at least twice a width
of power cable 324.
[0079] The second string guide 316B is mounted to the second bow
limb 312A and rotatable around a second axis 318B. The second
string guide 316B includes a second draw string journal 320B
oriented generally perpendicular to the second axis 318B.
[0080] The draw string 314 is received in the first and second draw
string journals 320A, 320B and is secured to the first string guide
316A at first attachment point 324. The draw string extends
adjacent to the down-range side 306 to the second string guide
316B, wraps around the second string guide 316B, and is attached at
the first axis 318A.
[0081] Power cable 324 is attached to the string guide 316A at
attachment point 326. See FIG. 4. Opposite end of the power cable
324 is attached to the axis 318B. In the illustrated embodiment,
power cable wraps 324 onto the first power cable take-up journal
322A and translates along the first power cable take-up journal
322A away from the first draw string journal 320A as the bow 300 is
drawn from the released configuration 328 to the drawn
configuration (see FIGS. 5-8).
[0082] FIG. 12 is a schematic illustration of a dual-cam crossbow
350 with a reverse draw configuration 352 in accordance with an
embodiment of the present disclosure. The crossbow 350 includes a
center portion 354 with down-range side 356 and up-range side 358.
First and second flexible limbs 362A, 362B ("362") are attached to
riser 360 and extend from opposite sides of the center portion 354.
Draw string 364 extends between first and second string guides
366A, 366B ("366"). In the illustrated embodiment, the string
guides 366 are substantially as shown in FIGS. 4-8.
[0083] The string guides 366 are mounted to the bow limb 362 and
are rotatable around first and second axis 368A, 368B ("368"),
respectively. The string guides 366 include first and second draw
string journals 370A, 370B ("370") and first and second power cable
take-up journals 372A, 372B ("372"), both of which are oriented
generally perpendicular to the axes 368, respectively. (See e.g.,
FIG. 8). The power cable take-up journals 372 include widths
measured along the axes 368 that is at least twice a width of power
cables 374A, 374B ("374").
[0084] The draw string 364 is received in the draw string journals
370 and is secured to the string guides 316 at first and second
attachment points 375A, 375B ("325").
[0085] Power cables 374 are attached to the string guides 316 at
attachment points 376A, 376B ("376"). See FIG. 4. Opposite ends
380A, 380B ("380") of the power cables 374 are attached to anchors
378A, 378B ("378") on the center portion 354. The power cables 374
preferably do not cross over the center support 354.
[0086] In the illustrated embodiment, power cables wrap 374 onto
the power cable take-up journal 372 and translates along the power
cable take-up journals 372 away from the draw string journals 370
as the bow 350 is drawn from the released configuration 378 to the
drawn configuration (see FIGS. 5-8).
[0087] The string guides disclosed herein can be used with a
variety of bows and crossbows, including those disclosed in
commonly assigned U.S. patent application Ser. No. 13/799,518,
entitled Energy Storage Device for a Bow, filed Mar. 13, 2013 and
Ser. No. 14/071,723, entitled DeCocking Mechanism for a Bow, filed
Nov. 5, 2013, both of which are hereby incorporated by
reference.
[0088] FIGS. 13A and 13B illustrate an alternate crossbow 400 in
accordance with an embodiment of the present disclosure. The
crossbow 400 includes a center rail 402 with a riser 404 mounted at
the distal end 406 and a stock 408 located at the proximal end 410.
The arrow 416 is suspended above the rail 402 before firing. In one
embodiment, the central rail 402 and the riser 404 may be a unitary
structure, such as, for example, a molded carbon fiber component.
In the illustrated embodiment, the stock 408 includes a scope mount
412 with a tactical, picatinny, or weaver mounting rail. Scope 414
preferably includes a reticle with gradations corresponding to the
ballistic drop of bolts 416 of particular weight. The riser 404
includes a pair of limbs 420A, 420B ("420") extending rearward
toward the proximal end 410. In the illustrate embodiment, the
limbs 420 have a generally concave shape directed toward the center
rail 402. The terms "bolt" and "arrow" are both used for the
projectiles launch by crossbows and, are used interchangeable
herein. Various arrows and nooks rare disclosed in commonly
assigned U.S. patent Ser. No. 15/673,784 entitled Arrow Assembly
for a Crossbow and Methods of Using Same, filed Aug. 10, 2017,
which is hereby incorporated by reference.
[0089] Draw string 501 is retracted to the drawn configuration 405
shown in FIGS. 13A and 13B using string carrier 480. As will be
discussed herein, the string carrier 480 slides along the center
rail 402 toward the riser 404 to engage the draw string 501 while
it is in a released configuration (see e.g., FIG. 21A). That is,
the string carrier 480 is captured by the center rail 402 and moves
in a single degree of freedom along a Y-axis. The engagement of the
string carrier 480 with the rail 402 (see e.g., FIG. 28E)
substantially prevents the string carrier 480 from moving in the
other five degrees of freedom (X-axis, Z-axis, pitch, roll, or yaw)
relative to the center rail 402 and the riser 404. As used herein,
"captured" refers to a string carrier that cannot be removed from
the center rail without disassembling the crossbow or the string
carrier.
[0090] When in the drawn configuration 405 tension forces 409A,
409B on the draw string 501 on opposite sides of the string carrier
480 are substantially the same, resulting in increased accuracy. In
one embodiment, tension force 409A is the same as tension force
409B within less than about 1.0%, and more preferably less than
about 0.5%, and most preferably less than about 0.1%. Consequently,
cocking and firing the crossbow 400 is highly repeatable. To the
extent that manufacturing variability creates inaccuracy in the
crossbow 400, any such inaccuracy are likewise highly repeatable,
which can be compensated for with appropriate windage and elevation
adjustments in the scope 414 (See FIG. 13B). The repeatability
provided by the present string carrier 480 results in a highly
accurate crossbow 400 at distances beyond the capabilities of prior
art crossbows.
[0091] By contrast, conventional cocking ropes, cocking sleds and
hand-cocking techniques lack the repeatability of the present
string carrier 480, resulting in reduced accuracy. Windage and
elevation adjustments cannot adequately compensate for random
variability introduced by prior art cocking mechanism.
[0092] A cocking mechanism 484 (see e.g., FIGS. 18A and 18B)
retracts the string carrier 480 to the retracted position
illustrated in FIG. 13B. The crossbow 400 includes a positive stop
(e.g., the stock 408) for the string carrier 480 that prevents the
draw string 501 from being retracted beyond the drawn configuration
405.
[0093] In the drawn configuration 405 the distance 407 between the
cam axles may be in the range of about between about 6 inches to
about 8 inches, and more preferably about 4 inches to about 8
inches. In one embodiment, the distance 407 between the axles in
the drawn configuration 405 is less than about 6 inches, and
alternatively, less than about 4 inches.
[0094] When in the drawn configuration 405 illustrated in FIG. 13A
the narrow separation 407 between the cam axels results in a
correspondingly small included angle 403 of the draw string 501.
The included angle 403 is the angle defined by the draw string 501
on either side of the string carrier 480 when in the drawing
configuration 405. The included angle 403 is preferably less than
about 25 degrees, and more preferably less than about 20 degrees.
The included angle 403 is typically between about 15 degrees to
about 25 degrees. The present string carrier 480 includes a catch
502 (see e.g., FIG. 17A) that engages a narrow segment of the draw
string 501 that permits the present small included angle 403.
[0095] The small included angle 403 that results from the narrow
separation 407 does not provide sufficient space to accommodate
conventional cocking mechanisms, such as cocking ropes and cocking
sleds disclosed in U.S. Pat. Nos. 6,095,128 (Bednar); 6,874,491
(Bednar); 8,573,192 (Bednar et al.); 9,335,115 (Bednar et al.); and
2015/0013654 (Bednar et al.), which are hereby incorporated by
reference. It will be appreciated that the cocking systems
disclosed herein are applicable to any type of crossbow, including
recurved crossbows that do not include cams or conventional
compound crossbows with power cables that crossover.
[0096] FIGS. 14A and 14B are top and bottom views of the riser 404.
Limbs 420 are attached to the riser 404 near the distal end 406 by
mounting brackets 422A, 422B ("422"). In the illustrated
embodiment, distal ends 424A, 424B ("424") of the limbs 420 extend
past the mounting brackets 422 to create pocket 426 that contains
arrowhead 428. Bumpers 430 are preferably attached to the distal
ends 424 of the limbs 420. The tip of the arrowhead 428 is
preferably completely contained within the pocket 426.
[0097] Pivots 432A, 432B ("432") attached to the riser 404 engage
with the limbs 420 proximally from the mounting brackets 422. The
pivots 432 provide a flexure point for the limbs 420 when the
crossbow 400 is in the drawn configuration.
[0098] Cams 440A, 440B ("440") are attached, to the limbs 420 by
axle mounts 442A, 442B ("442"). The cams 440 preferably have a
maximum diameter 441 less than the power stroke (see e.g., FIG. 5)
divided by about 3.5 for a reverse draw configuration. For example,
if the power stroke is about 13 inches, the maximum diameter 441 of
the cams 440 is preferably less than about 3.7 inches. The cams 440
preferably have a maximum diameter 441 less than the power stroke
(see e.g., FIG. 5) divided by about 5.0 for a non-reverse draw
configuration. For example, if the power stroke is about 13 inches,
the maximum diameter 441 of the cams 440 is preferably less than
about 2.6 inches. The cams 440 preferably have a maximum diameter
of less than about 4.0 inches, and more preferably less than about
3.5 inches. A highly compact crossbow with an included angle of
less than about 25 degrees preferably has cams with a maximum
diameter of less than about 3.0 inches.
[0099] In the illustrated embodiment, the axle mounts 442 are
attached to the limbs 420 offset a distance 446 from the proximal
ends 444A, 444B ("444") of the limbs 420. Due to their concave
shape, greatest width 448 of the limbs 420 (in both the drawn
configuration and the release configuration) preferably occurs at a
location between the axle mounts 442 and the pivots 432, not at the
proximal ends 444.
[0100] The offset 446 of the axle mounts 442 maximizes the speed of
the limbs 420, minimizes limb vibration, and maximizes energy
transfer to the bolts 416. In particular, the offset 446 is similar
to hitting a baseball with a baseball bat at a location offset from
the tip of the bat, commonly referred to as the "sweet spot". The
size of the offset 446 is determined empirically for each type of
limb. In the illustrated embodiment, the offset 446 is about 1.5 to
about 4 inches, and more preferably about 2 to about 3 inches.
[0101] Tunable arrow rest 490 is positioned just behind the pocket
426. A pair of supports 492 are secured near opposite sides of the
bolt 416 by fasteners 494. The supports 492 preferably slide in the
plane of the limbs 420. As best illustrated in FIG. 14C, the
separation 496 between the supports 492 can be adjusted to raise or
lower front end of the bolt 416 relative to the draw string 501. In
particular, by increasing the separation 496 between the supports
492 the curved profile of the front end of the bolt 416 is lowered
relative to the string carrier 480 (see FIG. 17A). Alternatively,
by decreasing, the separation 496 the curved profile of the bolt
416 is raised.
[0102] FIG. 14B illustrates the bottom of the riser 404. Rail 450
on the riser 404 is used as the attachment point for accessories,
such as quiver 452 for holding bolts 416 and cocking handle 454
that engages with pins 570 to rotate the drive shaft 564 (see FIG.
18A).
[0103] FIG. 14D illustrates the cocking handle 454 in greater
detail. Distal end 700 is configured to engage with drive shaft 564
and pins 570 illustrated in FIG. 118A. Center recess 702 receives
the drive shaft 564 and the undercuts 704 engage with, the pins 570
when the system is under tension. Consequently, when cocking or
uncocking the crossbow 400 the tension in the system locks the pins
570 into the undercuts 704. When tension in the system is removed,
the cocking handle 454 can be rotated a few degrees and disengaged
from the drive shaft 564.
[0104] The distal end 700 includes stem 706 that extends into
hollow handle 708. Pins 710 permit the stem 706 to rotate a few
degrees around pin 712 in either direction within the hollow handle
708. As best illustrated in FIG. 14E, torque assembly 714 is
located in hollow handle 708 that resists rotation of the stem 706
until a pre-set torque is reached Once that torque threshold is
exceeded, the stem 706 breaks free of block 716 and rotates within
the hollow handle 708, generating an audible noise and snapping
sensation that signal to the user that the crossbow 400 is fully
cocked.
[0105] FIGS. 14F and 14G illustrate a mounting system 730 for the
quiver 452 and the cocking handle 454. Quiver spine 732 includes a
pair of mounting posts 734 spaced to engage with openings 736 in
the mounting bracket 738. Magazine catch 740 (see FIG. 14G) slides
within mounting bracket 738. Spring 742 biases the magazine catch
740 in direction 744. Openings 746 in the magazine catch 740 engage
with undercuts 748 on the mounting posts 734 under pressure from
the spring 742. To remove the quiver 452 the user presses the
handle 750 in direction 752 until the openings 746 in the magazine
catch 740 are aligned with the openings 736 in the mounting bracket
738. Once aligned, the mounting posts 734 can be removed from the
mounting bracket 738.
[0106] FIG. 15 is a front view of the crossbow 400 with the draw
string or the power cables removed to better illustrate the cams
440 having upper and lower helical journals 460A, 460B above and
below draw string journal 464. As illustrated in FIG. 21A, separate
power cables 610A, 610B are operatively engaged with each of the
helical journals 460A, 460B, and minimizing torque on the cams 440.
The draw string journal 464 defines plane 466 that passes through
the bolt 416. The helical journals 460A, 460B move the power cables
610A, 610B in directions 468A, 468B, respectively, away from the
plane 466 as the bow 400 is drawn.
[0107] FIGS. 16A and 16B are upper and lower perspective views of
the cams 440 with the power cables and draw string removed. Recess
470 contains draw string mount 472 located generally in the plane
466 of the draw string journal 464. Power cable attachment 462A and
pivot post 463A correspond to helical journal 460A. As best
illustrated in FIG. 16B, power cable attachment 462B and pivot post
463B corresponds to the helical journal 460B. The pivot pots 463
serve to take-up a portion of the power cables 610 and redirect the
power cables 610 onto the helical journals 460.
[0108] FIGS. 17A through 17D illustrate string carrier 480 for the
crossbow 400 in accordance with an embodiment of the present
disclosure. As best illustrated in FIG. 21A, the string carrier 480
slides along axis 482 of the center rail 402 to the location 483
(see FIG. 21A) to capture the draw string 501. After the string
carrier 480 captures the draw string 501, the cocking mechanism 484
(see FIGS. 18A and 18B) is used to return the string carrier 480
back to the position illustrated in FIGS. 17A and 17B at the
proximal end 410 of the crossbow 400 and into engagement with
trigger 558.
[0109] The string carrier 480 includes fingers 500 on catch 502
that engage the draw string 501. The catch 502 is illustrated in a
closed position 504. After firing the crossbow the catch 502 is
retained in open position 505 (see FIG. 18B), such as for example,
by spring 510. In the illustrated embodiment, the catch biasing
force is applied to the catch 502 by spring 510 to rotate in
direction 506 around pin 508 and retains the catch 502 in the open
position 505. Absent an external force, the catch 502 automatically
move to open position 505 (see FIG. 18B) and releases the draw
string 501. As used herein, "closed position" refers to any
configuration that retains a draw string and "open position" refers
to any configuration that releases the draw string.
[0110] In the closed position 504 illustrated in FIGS. 17A, 17B,
18A, recess 512 on sear 514 engages low friction device 513 at rear
edge of the catch 502 at interface 533 to retain the catch 502 in
the closed position 504. The sear 514 is biased in direction 516 by
a sear biasing force applied by spring 511 to engage with and
retain the catch 502 in the closed position 504.
[0111] FIG. 17D illustrates the string carrier 480 with the sear
514 removed for clarity. In the illustrated embodiment, the low
friction device 513 is a roller pin 523 mounted in rear portion of
the catch 520. In one embodiment, the roller pin 523 has a diameter
corresponding generally to the diameter of the recess 512. The
roller pin 523 is preferably supported by ball bearings 525 to
reduce friction between the catch 502 and the recess 512 when
firing the crossbow 400. A force necessary to overcome the friction
at the interface 533 to release the catch 502 is preferably less
than about 1 pound, substantially reducing the trigger pull weight.
In an alternate embodiment, the positions of the roller pin 523 and
the ball bearings 525 can be reversed so that the sear 514 engages
directly on the ball bearings 525.
[0112] In one embodiment, a force necessary to overcome the
friction at the interface 533 to release the catch 502 is
preferably less than the biasing force applied to the sear 514 by
the spring 511. This feature causes the sear 514 to return fully to
the cocked position 524 in the event the trigger 558 is partially
depressed, but then released before the catch 502 releases the draw
string 501.
[0113] In another embodiment, a force necessary to overcome the
friction at the interface 533 to release the catch 502 is
preferably less than about 3.2%, and more preferably less than
about 1.6% of the draw force to retain the draw string 501 to the
drawn configuration. The draw force can optionally be measured as
the force on the flexible tension member 585 when the string
carrier 480 is in the drawn position (See FIG. 18A).
[0114] Turning back to FIGS. 17A and 17B, when in safe position 509
shoulder 520 on safety 522 retains the sear 514 in a cocked
position 524 and the catch 502 in the closed position 504. Safety
button 530 is used to move the safety 522 in direction 532 from the
safe position 509 illustrated in FIGS. 17A and 17B to free position
553 (see FIG. 18B) with the shoulder 520 disengaged from the sear
514.
[0115] A dry fire lockout biasing force is applied by spring 540 to
bias dry fire lockout 542 toward the catch 502. Distal end 544 of
the dry fire lockout 542 engages the sear 514 in a lockout position
541 to prevent the sear 514 from releasing the catch 502. Even if
the safety 522 is disengaged from the sear 514, the distal end 544
of the dry fire lockout 542 retains the sear 514 in the cocked
position 524 to prevent the catch 502 from releasing the draw
string 501.
[0116] FIG. 17C illustrates the string carrier 480 with the catch
502 removed for clarity. Nock 417 of the bolt 416 is engaged with
the dry fire lockout 542 and rotated it in the direction 546.
Distal end 544 of the dry fire lockout 542 is now in disengaged
position 547 relative to the sear 514. Once the safety 522 is
removed from the safe position 509 using the safety button 530, the
crossbow 400 can be fired. In the illustrated embodiment, the nock
417 is a clip-on version that flexes to form a snap-fit engagement
with the draw string 501. Only when a bolt 416 is fully engaged
with the draw string 501 will the dry fire lockout 542 be in the
disengaged position 547 that permits the sear 514 to release the
catch 502. Suitable materials and other aspects of the nook 417 are
disclosed in U.S. patent application Ser. No. 15/631,016, entitled
HIGH IMPACT STRENGTH LIGHTED NOCK ASSEMBLY, filed, Jun. 23, 2017
and U.S. patent application Ser. No. 15/631,004, entitled HIGH
IMPACT STRENGTH NOCK ASSEMBLY, filed Jun. 23, 2017, the entire
disclosure of which are both hereby incorporated by reference.
[0117] FIGS. 18A and 18B illustrate the relationship between the
string carrier 480, the cocking mechanism 484, and the trigger
assembly 550 that form string control assembly 551. The trigger
assembly 550 is mounted in the stock 408, separate from the string
carrier 480. Only when the string carrier 480 is fully retracted
into the stock 408 is the trigger pawl 552 positioned adjacent to
the sear 514. When the user is ready to fire the crossbow 400, the
safety button 530 is moved in direction 532 to a free position 553
where the extension 515 is disengaged from the shoulder 520. When
the trigger 558 is depressed the sear 514 rotating in direction 517
to a de-cocked position 557 and the catch 502 moves to the open
position 505 to release the draw string 501.
[0118] As best illustrate in FIG. 18B, after firing the crossbow
the sear 514 is in a de-cocked position 557 and the safety 522 is
in the free position 553. The catch 502 retains the sear 514 in the
de-cocked position 557 even though the spring 511 biases it toward
the cocked position 524. In the de-cocked position 557 the sear 514
retains the dry fire lockout 542 in the disengaged position 547
even though the spring 540 biases it toward the lockout position
541. The extension 515 on the sear 514 is located in recess 521 on
the safety 522.
[0119] To cock the crossbow 400 again the string carrier 480 is
moved forward to location 483 (see FIG. 21A) into engagement with
the draw string 501. Lower edge 503 of the catch 502 engages the
draw string 501 and overcomes the force of spring 510 to
automatically push the catch 502 to the closed position 504 (See
FIG. 18A). Spring 511 automatically rotates the sear 514 back into
the cocked position 524 so recess 512 formed interface 533 with the
catch 502. Rotation of the sear 514 causes the extension 515 to
slide, along the surface of the recess 521 until it engages with
the shoulder 520 on the safety 522 in the safe position 509. With
the sear 514 back in the cocked position 524 (See FIG. 18A), the
spring 540 biases dry fire lockout 542 to the lockout position 541
so the distal end 544 engages the sear 514 to prevent the catch 502
from releasing the draw string 501 (See FIG. 18A) until an arrow is
inserted into the string carrier 480. Consequently, when the string
carrier 480 is pushed into engagement with the draw string 501, the
draw string 501 pushes the catch 502 from the open position 505 to
the closed position 504 to automatically (i) couple the sear 514
with the catch 502 at the interface 533 to retain the catch 502 in
the closed position 504, (ii) move the safety 522 to the safe
position 509 coupled with the sear 514 to retain the sear 514 in
the cocked position 524, and (iii) move the dry fire lockout 542 to
the lockout position 541 to block the sear 514 from moving to the
de-cocked position 557.
[0120] The cocking mechanism 484 includes a rotating member, such
as the spool 560, with a flexible tension member, such as for
example, a belt, a tape or webbing material 585, attached to pin
587 on the string carrier 480. As best illustrated in FIGS. 19 and
20, the cocking mechanism 484 includes drive shaft 564 with a pair
of drive gears 566 meshed with gear teeth 568 on opposite sides of
the spool 560. Consequently, the spool 560 is subject to equalize
torque applied to the spool 560 during the cocking operation.
Cocking handle 454 that releasably attaches to either of exposed
ends of pin 570 of the drive shaft 564.
[0121] A pair of pawls 572A, 572B ("572") include teeth 574 (see
FIG. 20) that are biased into engage with the gear teeth 568. The
pawls 572 are preferably offset 1/2 the gear tooth 568 spacing so
that when the teeth 574 of one pawl 572 are disengaged from the
gear teeth 568, the teeth 574 on the other pawl 572 are positioned
to engage the gear teeth 568. Consequently, during winding of the
spool 560, the teeth 574 on one of the pawls 572 are always
positioned to engage with the gear teeth 568 on the spool. If the
user inadvertently released the cocking handle 454 when the
crossbow 400 is under tension, one of the pawls 572 is always in
position to arrest rotation of the spool 560.
[0122] In operation, the user presses the release 576 to disengage
the pawls 572 from the spool 560 and proceeds to rotate the cocking
handle 454 to move the string carrier 480 in either direction 482
along the rail 402 to cock or de-cocking the crossbow 400.
Alternatively, the crossbow 400 can be cocked without depressing
the release 576. but the pawls 572 will make a clicking sound as
they advance over the gear teeth 568.
[0123] FIGS. 21A and 21B illustrate the crossbow 400 in the
released configuration 600. Draw string 501 is located adjacent
down-range side 602 of the cams 440 in a reverse draw configuration
604. In the illustrated embodiment of the released configuration
600 the draw string 501 is adjacent stops 606 attached to power
cable bracket 608.
[0124] Upper power cables 610A are attached to the power cable
bracket 608 at upper attachment points 612A and to power cable
attachments 462A on the cams 440 (see also FIG. 22A). Lower power
cables 610B are attached to the power cable bracket 608 at lower
attachment points 612B and to the power cable attachments 462B on
the cams 440 (see also FIG. 22B). The attachment points 612 are
static relative to the riser 404, rather than dynamic attachment
points on the opposite limbs or opposite cams. As used herein,
"static attachment point" refers to a cabling system in which power
cables are attached to a fixed point relative to the riser, and not
attached to the opposite limb or opposite cam.
[0125] In the illustrated embodiment, the attachment points 612A,
612B for the respective power cables 610 are located on opposite
sides of the center rail 402. Consequently, the power cables 610 do
not cross over the center rail 402. As used herein, "without
crossover" refers to a cabling system in which power cables do not
pass through a vertical plane bisecting the center rail 402.
[0126] As best illustrated in FIG. 21B, the upper and lower
attachment points 612A, 612B on the power cable bracket 608
maintains gap 614 between the upper and lower power cables 610A,
610B greater than the gap at the axes of the cams 440.
Consequently, the power cables 610A, 610B angle toward each other
near the cams 440.
[0127] FIGS. 22A and 22B are upper and lower perspective views of
the cams 440 with the cables 510, 610A, and 610B in the released
configuration 600. The cams 440 are preferably symmetrical so only
one of the cams 440 is illustrated. Upper power cables 610A are
attached to power cable attachments 462A, wrap around the upper
pivots 463A and then return toward the bow 400 to attach to the
power cable bracket 608 (see FIG. 21A). The draw cable 501 is
attached to the draw string mount 472 and then wraps almost
completely around the cam 440 in the draw string journal 464 to the
down range side 602.
[0128] FIGS. 23A and 23B illustrate the crossbow 400 in the drawn
configuration 620. Draw string 501 extends from the down-range side
602 of the cams 440 in a reverse draw configuration 604. As best
illustrated in FIG. 23B, the power cables 610A, 610B move away from
the cams 440 as they wrap onto the upper and lower helical journals
460A, 460B. In the drawn configuration 620 the power cables 610A,
610B are generally parallel (compare the angled relationship in the
released configuration 600 illustrated in FIG. 21B). The resulting
gap 622 permits the power cable attachments 462 and pivot 463 to
pass under the power cables 610 without contacting them (see also,
FIGS. 24A and 24B) as the crossbow 400 moves between the released
configuration 600 and the drawn configuration 620. As best
illustrated in FIG. 24C, gaps 623 between surfaces 625 of the cams
440 and the power cables 610 is greater than height 627 of the
power cable attachments 462 and the pivots 463.
[0129] FIGS. 24A and 24B are upper and lower perspective views of
the cams 440 with the cables 510, 610A, and 610B in the drawn
configuration 620. The upper power cables 610A wraps around the
upper pivots 463A and then onto the upper helical journal 460A,
before returning to the power cable bracket 608 (see FIG. 23A).
Similarly, the lower power cables 610B wraps around the lower
pivots 463B and then onto the lower journal 460B, before returning
to the power cable bracket 608 (see FIG. 23A). The draw cable 501
is attached to the draw string mount 472 unwraps almost completely
from the draw string journal 464 of the cam 440 to the down range
side 602.
[0130] In the illustrated embodiment, the draw string journal 464
rotates between about 270 degrees and about 330 degrees, and more
preferably from about 300 degrees to about 360 degrees, when the
crossbow 400 is drawn from the, released configuration 600 to the
drawn configuration 620. In another embodiment, the draw string
journal 464 rotates more than 360 degrees (see FIG. 9A).
[0131] FIGS. 25A and 25B illustrate an alternate string carrier
480A for the crossbow 400 in accordance with an embodiment of the
present disclosure. The string carrier 480A is similar to the
assembly illustrated in FIGS. 17A-17C, so the same reference
numbers are used where applicable.
[0132] FIG. 25A illustrates the catch 502 is illustrated in a
closed position 504. The catch 502 is biased by spring 510 to
rotate in direction 506 and retained in open position 505 (see FIG.
18B). Absent an external force, the catch 502 automatically
releases the draw string 501 (See FIG. 17A). In the closed position
504 illustrated in FIG. 25A, recess 512 on sear 514 engages with
low friction device 513 on the catch 502 to retain the catch 502 in
the closed position 504. The sear 514 is biased by spring 519 to
retain the catch 502 in the closed position 504. The safety 522
operates as discussed in connection with FIGS. 17A-17C.
[0133] Spring 540A biases dry fire lockout 542A toward the catch
502. Distal end 544A of the dry fire lockout 542A engages the sear
514 in a lockout position 541 to prevent the sear 514 from
releasing the catch 502. Even if the safety 522 is disengaged from
the sear 514, the distal end 544A of the dry fire lockout 542A
locks the sear 514 in the closed position 504 to prevent the catch
502 from releasing the draw string 501.
[0134] As illustrated in FIG. 25B, when the bolt 416 is positioned
on the string carrier 480A the rear portions or arms on the clip-on
nock 417 extends past the draw string 501 (so a portion of the nock
417 is behind the draw sting 501) and engages with the portion 543A
on the dry fire lockout 542A, causing the dry fire lockout 542A to
rotate in direction 546A so that the distal end 544A is disengaged
from the sear 514. In the illustrated embodiment, the portion 543A
is a protrusion or finger on the dry fire lockout 542A. Only when a
bolt 416 is fully engaged with the draw string 501 will the dry
fire lockout 542A permit the sear 514 to release the catch 502.
[0135] In the illustrated embodiment, the portion 543A on the dry
fire lockout 542A is positioned behind the draw string location
501A. As used herein, the phrase "behind the draw string" refers to
a region between a draw string and a proximal end of a crossbow.
Conventional flat or half-moon nocks do not extend far enough
rearward to reach the portion 543A of the dry fire lockout 542A,
reducing the chance that non-approved arrows can be launched by the
crossbow 400.
[0136] FIGS. 25A and 25B illustrate elongated arrow capture recess
650 that retains rear portion 419 of the arrow 416 and the clip-on
nock 417 engaged with the string carrier 480A in accordance with an
embodiment of the present disclosure. The elongated arrow capture
recess 650 extends along a direction of travel of an arrow launched
from the crossbow 400. The arrow capture recess 650 is offset above
the rail 402 as is the rest 490 (see FIG. 14C) so the arrow 416 is
suspended above the rail 402 (see FIG. 13B).
[0137] Upper roller 652 is located near the entrance of the arrow
capture recess 650. The upper roller 652 is configured to rotate in
the direction of travel of the arrow 416 as it is launched. That
is, the axis of rotation of the upper roller 652 is perpendicular
to a longitudinal axis of the arrow 416. The upper roller 652 is
displaced within the slot in a direction generally perpendicular to
the arrow 416, while spring 654 biases the upper roller 652 in
direction 656 against the arrow 416. As best illustrated in FIG.
25C, the arrow capture recess 650 extends rearward past the fingers
500 on catch 502. The string carrier 480A includes lower angled
surfaces 658A, 658B ("658") and upper angled surfaces 660A, 660B
("660") configured to engage the arrow 416 around the perimeter of
the rear portion.
[0138] In the illustrated embodiment, the clip-on nock 417 must be
fully engaged with the draw string 510A near the rear of the arrow
capture recess 650 to disengage the dry fire lock out 542A. In this
configuration (see FIG. 25B), the rear portion 419 of the arrow 416
is fully engaged with the arrow capture recess 650, surrounded by
the rigid structure of the string carrier 480A.
[0139] In one embodiment, the lower angled surfaces 658 do not
support the arrow 416 in the arrow capture recess 650 unless the
clip-on neck 417 is used. In particular, the upper angled surfaces
660 prevent the nock 417 from rising upward when the crossbow 400
is fired, but the arrow 417 tends to slide downward off the lower
angled surfaces 658 unless the clip-on nock 417 is fully engaged
with the draw string 510A.
[0140] By contrast, prior art crossbows typically include a leaf
spring or other biasing structure to retain the arrow against the
rail. These devices tend to break and are subject to tampering,
which can compromise accuracy.
[0141] FIG. 26A illustrates an alternate the cocking handle 720
with an integral clutch to prevent excessive torque on the cocking
mechanism 484 and tension on the flexible tension member 585 in
accordance with an embodiment of the present disclosure. As
discussed in connection with FIG. 14D, distal end 700 is configured
to engage with drive shaft 564 and pins 570. Center recess 702
receives the drive shaft 564 and the undercuts 704 engage with the
pins 570 when the system is under tension. Consequently, when
cocking or uncocking the crossbow 400 the tension in the system
locks the pins 570 into the undercuts 704. When tension in the
system is removed, the cocking handle 454 can be rotated a few
degrees and disengaged from the drive shaft 564.
[0142] FIG. 26B is an exploded view of the cocking handle 720 of
FIG. 26A. Distal end 700 contains a torque control mechanism 722.
Coupling 724 that engages with the drive shaft 564 is contained
between a pair of opposing friction washers 726 and a pair of
opposing notched washers 728 within head 729. Pins 730 couple the
notched washers 728. One or more spring washers 732, such as for
example Belleville washers, conical spring washers, and the like,
maintain a compressive load on the coupling 724 to control the
torque applied to the drive shaft 564. The magnitude of the
compressive load applied to the coupling establishes a pre-set
maximum torque that can be, applied to the drive shaft 564. The
maximum torque or break-away torque at which the coupling 724 slips
relative to the cocking handle 720 preferably corresponds to about
110% to about 150% of the force on the flexible tension member 585
during cocking of the crossbow 400.
[0143] In an alternate embodiment, the drive shaft 564 is three
discrete pieces 565A, 565B, 565C connected by torque control
mechanisms located in housings 567A, 567B. A torque control
mechanism 722 generally as illustrated in FIG. 26B may be used.
[0144] The string carrier 480 hits a mechanical stop when it is
fully retracted, which corresponds to maximum draw string 501
tension. Tension on the draw string 501 is highly repeatable and
uniform throughout the string system due to the operation of the
string carrier 480. Further pressure on the cocking handle 720
causes the coupling 724 to slip within the head 729, preventing
excessive torque on the cocking mechanism 484 and tension on the
flexible tension member 585.
[0145] FIGS. 27A-27C illustrates an alternate tunable arrow rest
750 in accordance with an embodiment of the present disclosure. The
tunable arrow rest 750 includes housing 760 that is positioned just
behind the pocket 426. A pair of spring loaded support rollers 752
are rotatably secured in slots 754 by pins 756. The support rollers
752 rotate freely around the pins 756. When compressed, the support
rollers 752 can be independently displaced in directions 758.
Springs 764 (see FIG. 27B) bias the pins 756 and the support
rollers 752 to the tops of the slots.
[0146] As best seen in FIG. 27B with the housing 760 removed, arrow
rest 750 is mounted to distal end 776 of the center rail 402 by
fasteners 762. Each of the support rollers 752 is biased to the
tops of the slots 754 by the springs 764. Rotating member 766 is
provided at the interface between the support rollers 752 and the
springs 764 to reduce friction and permit the support rollers 752
to turn freely.
[0147] As best seen in FIGS. 27C and 27D the housing 760 includes
enlarged openings 768 with diameters larger than the diameters of
the fasteners 762. Consequently, the position of the arrow rest 750
can be adjusted (i.e., tuned) in at three degrees of freedom--the
Y-direction 770, the Z-direction 772, and roll 774 relative to the
center rail 402. FIG. 27D illustrates an arrow 412 with arrowhead
428 positioned on the support rollers 752 and the various degrees
of freedom 770, 772, 774 available for tuning the arrow rest
750.
[0148] FIGS. 28A-28E illustrate alternate cocking systems 800 in
accordance with an embodiment of the present disclosure in which
the cocking mechanism 484 located in the stock 408 and the flexible
tension member 585 are not required. In one embodiment, the string
carrier 480 when not engaged with the draw string 501 slides freely
back and forth along the rail between the released configuration
and the drawn configuration. At least one cocking rope engagement
mechanism 802 is attached to the string carrier 480. In the
illustrated embodiment, a pair of pulleys 804 are pivotally
attached to opposite sides of the string carrier 480 brackets 806
and pivot pins 808.
[0149] A variety of conventional cocking ropes 810 can releasably
engage with the pulleys 804. The hooks found on conventional
cocking ropes are not required. As best illustrated in FIG. 28C,
the user pulls handles 812 to draw the string carrier 480 to the
retracted position 814. The cocking rope 810 can be a single
discrete segment of rope or two discrete segments of rope. In the
illustrated embodiment, two discrete cocking ropes 810 are each
attached to opposite sides of the stock 408 at anchors 816 and wrap
around the pulleys 804 to provide the user with mechanical
advantage when cocking the bow 400.
[0150] It will be appreciated that a variety of different cocking
rope configurations can be used with the string carrier 480, such
as disclosed in U.S. Pat. Nos. 6,095,128 (Bednar): 6,874,491
(Bednar); 8,573,192 (Bednar et al.); 9,335,115 (Bednar et al.); and
2015/0013654 (Bednar et al.), which are hereby incorporated by
reference.
[0151] In one embodiment, the cocking ropes 810 retract into
handles 812 for convenient storage. For example, protrusions 826 on
handles 812 can optionally contain a spring-loaded spool that
automatically retracts the cocking ropes 810 when not in use, such
as disclosed in U.S. Pat. No. 8,573,192 (Bednar et al.). In another
embodiment, a retraction mechanism for storing the cocking ropes
when not in use are attached to the stock 408 at the location of
the anchors 816 such as disclosed in U.S. Pat. No. 6,874,491
(Bednar). In another embodiment, a cocking rope retraction system
with a spool and crank handle can be attached to the stock 408,
such as illustrated in U.S. Pat. No. 7,174,884 (the '884 Kempf
Patent").
[0152] In operation, when the draw string 501 is in the released
configuration 600 the user slides the string carrier 480 forward
along the rail into engagement with the draw string 501. The catch
502 (see e.g., FIG. 25A) on the string carrier 480 engages the draw
string 501 as discussed herein. The user pulls the handles 812
until the string carrier 480 is retained in the retracted position
814 by retaining mechanism 817. The retaining mechanism 817 retains
the string carrier 480 in the retracted position 814 independent of
the cocking ropes 810. That is, once the string carrier 480 is in
the retracted position 814 the retaining mechanism 817 the cocking
ropes 810 can be removed and stored.
[0153] In the embodiment illustrated in FIGS. 28D and 28E the
retaining mechanism 817 is hook 818 attached to the stock
configured to couple with pin 819 on the string carrier 480.
Release lever 820 moves the hook 818 in direction 822 to disengage
it from the pin 819 on the string carrier 480. When the crossbow is
in the drawn configuration, the force 824 applied to the string
carrier 480 by the draw string prevent the hook 818 from
inadvertently disengaging from the pin 819 on the string carrier
480. During transport the string carrier 480 can be secured to
either the draw string 501 in the release configuration 600 or to
the hook 818 in the retracted configuration 814 without the draw
string 501 attached.
[0154] FIG. 28F illustrates an alternate embodiment where the
cocking rope 810 is a single segment that wraps around the stock
408 rather than requiring anchors 816. The opposite ends of the
cocking rope 810 then wrap around the cocking rope engagement
mechanisms on opposite sides of the string carrier 480. The user
pulls the handles 812 toward the proximal end of the crossbow 400
to manually retract the string carrier 480 to the retracted
position and the draw siring to the drawing configuration.
[0155] In order to de-cock the crossbow 400, the user pulls the
handles 812 to retract the string carrier 480 toward the stock 408
a sufficient amount to disengage the hook 818 from the pin 819. In
one embodiment, the user rotates the release lever 820 in direction
821 about 90 degrees. The release lever 820 biases the hook 818 in
direction 822, but the force 824 prevents the hook 818 from moving
in direction 822. The user then pulls the handles 812 toward the
stock 408 to remove the force 824 from the hook 818. Once the pin
819 clears the hook 818 the biasing force applied by the release
lever 820 moves the hook 818 in direction 822. The user can now
slowly move the string, carrier 480 toward the released
configuration 600.
[0156] As illustrated in FIG. 29 extensions 830 on the string
carrier 480 are engaged with undercuts 832 in the rail 402.
Consequently, the string carrier 480 is captured by the rail 402
and can only move back and forth along the rail 402 (Y-axis), but
cannot move in the Z-axis or X-axis direction, or in pitch 834,
roll 836, or yaw 838, relative to the bowstring 501. In an
alternate embodiment, the extension 830 are located on the exterior
surface of the rail 402 and the string carrier 480 wraps around the
rail 402 to engage the undercuts 832. In one embodiment, the
extensions 830 are retractable so the string carrier 480 can be
removed from the rail 402. With the extensions 830 in the extended
position illustrated in FIG. 29 the string carrier 480 is captured
by the rail 402.
[0157] In particular, when in the drawn configuration tension
forces on the draw string 501 on opposite sides of the string
carrier 480 are substantially the same, within less than about
1.0%, and more preferably less than about 0.5%, and most preferably
less than about 0.1%. Consequently, cocking and firing the crossbow
400 is highly repeatable.
[0158] To the extent that manufacturing variability creates
inaccuracy in the crossbow 400, any such inaccuracy are likewise
highly repeatable, which can be compensated for with appropriate
windage and elevation adjustments in the scope 414 (See FIG. 13B).
The repeatability provided by the present cocking systems 484, 800
results in a highly accurate crossbow 400 at distances beyond the
capabilities of prior art crossbows. For example, the cocking
systems 484, 800 in combination with windage and elevation
adjustments permits groupings of three arrows in a three-inch
diameter target at about 100 yards, and groupings of three arrows
in a two-inch diameter target at about 50 yards.
[0159] FIGS. 30A and 30B illustrate an alternate crossbow 900 in
accordance with an embodiment of the present disclosure. FIG. 30A
illustrates the crossbow 900 in the released configuration 600 and
FIG. 30B illustrates the drawn configuration 405.
[0160] The crossbow 900 includes a center rail 402 with a riser 404
mounted at the distal end 406 and a stock 408 located at the
proximal end 410. The center rail 402 and riser 404 may be referred
to herein as the frame 904. The riser 404 includes a pair of limbs
420A, 420B ("420") extending rearward toward the proximal end
410.
[0161] Cams 440A, 440B are attached to the frame 904, rather than
the limbs 420. In the illustrated embodiment, the cams 440 are
attached to the center rail 402 by axle mounts 442A, 442B. The cams
440 rotate around axes 443A, 443B ("443") on respective axle mounts
442A, 442B, but otherwise do not move relative to the frame 904.
The locations of axes 443 are fixed relative to the center rail 402
and the riser 404, even as the limbs 420 and the draw string 501
move. Consequently, energy stored in the limbs 420 when the
crossbow 900 is in the drawn configuration 405 is not diverted to
accelerating the mass of the cams 440, resulting in greater energy
transferred to the arrow 416. The stationary cams 440 and cam axles
442 also eliminates any inaccuracy introduced by moving the cams
440 with the limbs 420 when firing a conventional crossbow.
[0162] Draw string 501 is engaged with draw string journals 464
(see e.g., FIG. 15) in a reverse draw configuration. Ends of the
draw string 501 are preferably attached to the cams 440 at draw
string mounts 472. The present crossbow 900 can also be configured
in a non-reverse draw configuration.
[0163] Power cables 610A, 610B are attached to the limbs 420A,
420B, respectively. Opposite ends of the power cables 610 are
attached to the power cable attachments 462 on the cams 440. The
cams 440 include power cable journals 460A, 460B that receive
respective power cables 610A, 610B as the draw string 510 is moved
from the released configuration 600 to the drawn configuration
405.
[0164] In the preferred embodiment, each limb 420 includes upper
and lower power cables 610 that engaged with upper and lower power
cable journals 460 on the cams 440 (see e.g., FIG. 15). In one
embodiment, the power cable journals 460 are the upper and lower
helical journals 460A, 460B located above and below draw string
journal 464 illustrated in FIG. 15. The helical journals 460A, 460B
preferably move the power cables 610A, 610B in directions 468A,
468B, respectively, away from the plane 466 as the bow 400 is drawn
(see e.g., FIG. 15).
[0165] Draw string 501 is preferably retracted to the drawn
configuration 405 shown in FIGS. 30B using the string carrier 480.
As discussed herein, the string carrier 480 slides along the center
rail 402 toward the riser 404 to engage the draw string 501 while
it is in a released configuration 600. The string carrier 480 is
preferably captured by the center rail. In one embodiment, the
cocking mechanism 484 (see e.g., FIGS. 18A and 18B) retracts the
string carrier 480 to the retracted position illustrated in FIG.
30B. In another embodiment, any of the alternate cocking systems
800 may be used with the present crossbow 900, such as those
illustrated in FIGS. 28A-28E. Foot stirrup 411 permits the user to
secure the crossbow 900 while using the alternate cocking systems
800
[0166] The stationary axes 443 preferably have a fixed separation
902 of between about 3 inches to about 8 inches, and more
preferably, about 4 inches. The drawn configuration 405 illustrated
in FIG. 30B results in small included angle 403 of the draw string
501. The included angle 403 is preferably less than about 15
degrees, and more preferably less than about 10 degrees. The power
stroke is preferably about 12 inches to about 16 inches.
[0167] In the drawn configuration 405 of FIG. 30B the draw string
501 is close to the rail 402. In one embodiment the draw string 501
in entirely contained within the rail 402 in the drawn
configuration 405. In another embodiment, the draw string 501 is
substantially surrounded by a string guard and/or the center rail
402 when in the drawn configuration 405. Consequently, the user is
shielded from the entire string path traversed by the draw string
501 between the drawn configuration 405 and the release
configuration 600.
[0168] FIG. 30C illustrates an alternate version of the crossbow
900 with limb tips 421A, 421B ("421") that overlap with cams 440A,
440B, respectively, in accordance with an embodiment of the present
disclosure. The overlap of the limb tips 421 with the cams 440 is
best seen from the top or rear of the crossbow 900. In one
embodiment, the limb 420A is a pair of upper and lower limbs (see
e.g., FIG. 15) with a pair of limb tips 421A that are positioned
above and below the cam 440A when in the drawn configuration 405.
Similarly, the limb 420B includes a pair of upper and lower limbs
with a pair of limb tips 421B that are positioned above and below
the cam 440B when in the drawn configuration 405. Configuring the
limb tips 421 to overlap the cams 440 permits the crossbow 900 to
be more compact in the drawn configuration 405.
[0169] FIGS. 31A and 31B illustrate an alternate crossbow 910 with
forward swept limbs 420 in accordance with an embodiment of the
present disclosure. The crossbow 910 is substantially the same as
the crossbow 900, except that the riser 404 is located closer to
the proximal end 410 and the limbs 420 extending forward toward the
distal end 406. A variation of the foot stirrup 411 is also
illustrated. The draw string 501 is arranged in a reverse draw
configuration, with the released configuration illustrated in FIG.
31A and the drawn configuration illustrated in FIG. 31B.
[0170] FIG. 31C illustrates an alternate version of the crossbow
910 with limb tips 421A, 421B ("421") that overlap with cams 440A,
440B, respectively, in accordance with an embodiment of the present
disclosure. The overlap of the limb tips 421 with the cams 440 is
best seen from the top or rear of the crossbow 900. Overlap or
overlapping refers to the limb tip being located above and/or below
the cams 440 within the outside perimeter of the cams 440. In one
embodiment, the limb 420A is a pair of upper and lower limbs (see
e.g., FIG. 15) with a pair of limb tips 421A that are positioned
above and below the cam 440A when in the drawn configuration 405.
Similarly, the limb 420B includes a pair of upper and lower limbs
with a pair of limb tips 421B that are positioned above and below
the cam 440B when in the drawn configuration 405. Configuring the
limb tips 421 to overlap the cams 440 permits the crossbow 900 to
be more compact in the drawn configuration 405.
[0171] FIG. 32 illustrates another alternate crossbow 920 with the
cams 440 attached to the riser 404 in accordance with an embodiment
of the present disclosure. The crossbow 920 is substantially the
same as the crossbow 900 except that the limbs 420 extending
forward toward the distal end 406.
[0172] The riser 404 extends along the center rail 402 to provide
attachment locations for both the limbs 420 and the cams 440. The
cams 440 are attached to the riser 404 closer to the distal end 406
and rotate around axes 443. In one embodiment, the axle mounts 442
are machined directly into the riser 404. Alternatively, the axial
mounts 442 are discrete components attached to the riser 404.
[0173] Center portions 922 of the riser 404 have a width 924
greater than the draw string 501 when in the drawn configuration
405 as illustrated in FIG. 32. String guard 926 extending over the
top of the crossbow 920 is optionally added to partially or fully
enclose the draw string 501. The string carrier 480 may also move
within the string guard 926. Consequently, the entire string path
traversed by the draw string 501 between the drawn configuration
405 and the release configuration 600 is optionally isolated from
the user.
[0174] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limit of that range and any other stated or intervening
value in that stated range is encompassed within this disclosure.
The upper and lower limits of these smaller ranges which may
independently be included in the smaller ranges is also encompassed
within the disclosure, subject to any specifically excluded limit
in the stated range. Where the stated range includes one or both of
the limits, ranges excluding either both of those included limits
are also included in the disclosure.
[0175] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this disclosure belongs.
Although any methods and materials similar or equivalent to those
described herein can also be used in the practice or testing of the
various methods and materials are now described. All patents and
publications mentioned herein, including those cited in the
Background of the application, are hereby incorporated by reference
to disclose and described the, methods and/or materials in
connection with which the publications are cited.
[0176] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present disclosure is not entitled to antedate such publication
by virtue of prior invention. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0177] Other embodiments, are possible. Although the description
above contains much specificity, these should not be construed as
limiting the scope of the disclosure, but as merely providing
illustrations of some of the presently preferred embodiments. It is
also contemplated that various combinations or sub-combinations of
the specific features and aspects of the embodiments may be made
and still fall within the scope of this disclosure. It should be
understood that various features and aspects of the disclosed
embodiments can be combined with or substituted for one another in
order to form varying modes disclosed. Thus, it is intended that
the scope of at least some of the present disclosure should not be
limited by the particular disclosed embodiments described
above.
[0178] Thus the scope of this disclosure should be determined by
the appended claims and their legal equivalents. Therefore, it will
be appreciated that the scope of the present disclosure fully
encompasses other embodiments which may become obvious to those
skilled in the art, and that the scope of the present disclosure is
accordingly to be limited by nothing other than, the appended
claims, in which reference to an element in the singular is not
intended to mean "one and only one" unless explicitly so stated,
but rather "one or more." All structural, chemical, and functional
equivalents to the elements of the above-described preferred
embodiment that are known to those of ordinary skill in the art are
expressly incorporated herein by reference and are intended to be
encompassed by the present claims. Moreover, it is not necessary
for a device or method to address each and every problem sought to
be solved by the present disclosure, for it to be encompassed by
the present claims. Furthermore, no element, component, or method
step in the present disclosure is intended to be dedicated to the
public regardless of whether the element, component, or method step
is explicitly recited in the claims.
* * * * *