Patent application title: LEVER REGULATED COMPOUND BOW
Inventors:
Gary L. Cooper (Pocahontas, AR, US)
IPC8 Class: AF41B510FI
USPC Class:
124 256
Class name: Spring bow compound bow
Publication date: 2010-03-25
Patent application number: 20100071677
Bow uses multiple groove modules on the limb tips
to spool bowstring and cables to provide desired energy storage and nock
travel, while simultaneously using a lever to regulate cam
synchronization, using split cable harnesses to deter limb twist, and
lever blocking draw stop means.Claims:
1. a.) An archery bow having a handle, a first and second limb attached to
ends of said handle,b.) rotating modules mounted on ends of said limbs,
said rotating modules having multiple grooves,c.) a bowstring attached to
said modules,d.) a rotatable lever mounted on a support extending from
said handle between said rotating modules, ande.) a cable extending from
one limb to the other limb, said cable means extending between said
limbs, being acted on by said lever when drawing said bow to compress
said limbs.
2. The bow of claim 1 wherein the multiple grooves are concentric about axles of said modules.
3. The bow of claim 1 wherein the multiple grooves are eccentric about axles of said modules.
4. The bow of claim 1 wherein the multiple grooves consist of one concentric groove and one eccentric groove.
5. The bow of claim 1 wherein the multiple grooves consist of one concentric and one cam groove.
6. The bow of claim 1 wherein the multiple grooves consist of one eccentric and one cam groove.
7. The bow of claim 1 wherein the multiple grooves consist of two cam grooves.
8. The bow of claim 1 wherein said cable extending from one limb to the other is attached to axles of modules on top and bottom limbs.
9. The bow of claim 1 wherein said cable extending from one limb to the other is split and attaches to ends of axles of modules outside the limbs.
10. The bow of claim 1 wherein said cable means is routed around pegs on said lever.
11. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves, andc.) a bowstring attached to said modules.d) a cable attached to a module of one limb and extending to and attaching to said lever; and a second cable attaching to module of second limb and extending to and attaching to said lever.
12. The bow of claim 1 wherein said lever is positioned at the midpoint between said modules.
13. The bow of claim 1 wherein said lever is positioned away from the midpoint between said modules.
14. The bow of claim 1 wherein modules vary the leverage applied to the lever compressing the limbs so that peak draw weight is held through a distance of the draw.
15. The bow of claim 1 wherein modules spool bowstring and cables at a rate coupled with the leverage applied to the lever compressing the limbs so that nock travel is straight and level.
16. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves,c.) a bowstring attached to said modules,d.) a rotatable lever mounted on a support extending from said handle between said rotating modules,e.) first cable means extending from one limb to said lever,f.) second cable means extending from second limb to said lever,g.) third cable means attached to the module of one limb and extending to and attaching to said lever, andh.) fourth cable means attached to the module of said second limb and extending to and attaching to said lever.
17. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves,c) a bowstring attached to said modules,d.) a rotatable lever mounted on a support extending from said handle,e.) first cable means extending from one limb to said lever is split and attaches to axles of said modulesf.) second cable means extending from said second limb to said lever, said second cable means being split and attaching to axles of said modules,g.) third cable means attached to the module of one limb and extending to and attaching to said lever, andh.) fourth cable means attached to the module of said second limb and extending to and attaching to said lever.
18. The bow of claim 11 wherein cable means extending from said limbs to said lever is split and attaches to axles of said modules.
19. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves,c.) a bowstring attached to said modules,d.) a rotatable lever mounted on a support extending from said handle between said rotating modules,e.) cable means extending between said limbs being acted on by said lever when drawing bow to compress said limbs, andf.) draw stop means prevents movement of said lever
20. The bow of claim 19 wherein draw stop means is an integral protrusion of said lever support.
21. The bow of claim 19 wherein draw stop means is a protrusion attached to said lever support.
22. The bow of claim 21 wherein said protrusion is a screw.
23. The bow of claim 19 wherein said draw stop means is an integral protrusion of said lever.
24. The bow of claim 19 wherein said draw stop means is a protrusion attached to said lever.
25. The bow of claim 24 wherein said protrusion is a screw.Description:
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001]Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002]Not Applicable.
BACKGROUND OF THE INVENTION
[0003]Early bows consisted of a simple stick with a string attached to each end. In 1969 compound bow U.S. Pat. No. 3,486,495 was granted to Holless Allen. By providing eccentric leverage modules on the end of limbs with operating cabling, the force draw curve of the Allen compound bow could be manipulated to store more energy during the draw cycle, firing a faster arrow and lessen the holding weight at full draw, allowing better aiming. By pulling on the bowstring it was unspooled from the modules, while cabling pulling on the opposing limbs was spooled on the modules. An accuracy problem was inherent in the design as it was difficult, because of manufacturing differences and stretch resulting in unequal lengths of cable, to keep consistent amounts of bowstring unspooled from each module on the limb tips. Thus the nock point would move from its previous path, resulting in an arrow launch different from that which the bow was originally tuned and sighted for, resulting in a loss of accuracy. The need existed for a bow whose nock travel will not be substantially affected by string stretch.
[0004]An additional problem is that one cam could move independently from another at the end of the draw. Thus there would be an inconsistent shift in nock travel at the string release. The dual feed Single Cam bow was invented to deal with the synchronization problem. However, since the midpoint of the bow string was at the idler, there were uneven lengths on opposing sides of the nock point, which resulted in nock movement with string stretch. Further, since the cam limb had no wide cable yoke equalizing pull on the outside of the limb tips, the angle of the cable from the cable guard caused the limb to twist as the bow was drawn and released, stressing the limb and laterally affecting nock travel.
[0005]Recently bows have become popular with cables attaching to the cams to synchronize the cams. However, again by having no wide cable yokes outside the limb tips they are undesirably twisted.
[0006]Thus there exists a need for a compound bow that is synchronized, has more consistent nock travel in case there is string stretch, does not have extreme limb twist affecting nock travel and limb durability, and has a solid draw stop where no bowstring can reel off either module at full draw.
[0007]The closest prior art I have found is from archeryhistory.com, compounds, onecam bows. In this design, the bow is very long with idlers instead of multiple groove modules. Multiple groove modules allow desirable short axle to axle bows, smaller, lighter lever, draw length adjustment, greater energy storage and speed, straight level more accurate nock travel and synchronized cams.
BRIEF SUMMARY OF THE INVENTION
[0008]It is an object of the current invention to provide a compound bow with synchronized cams whose effective cable lengths remain closely matched resulting in consistent nock travel and superior accuracy. The present invention comprises a handle portion, an upper and lower limb supported by the handle portion, and a rotatable synchronizing lever supported by an arm attached to the bow handle. A first rotatable module with a bowstring groove and a cable groove is mounted on the top limb for rotation about an axle. A second rotatable module with a bowstring groove and a cable groove is mounted on the bottom limb for rotation about a second axle. Upon pulling a bowstring attached to the rotatable modules, cables attached to the modules pull on said lever located between the modules. The lever acts upon a cable or cables to pull and compress the limbs. Rotatable modules are thus synchronized since cabling from either module pulling on the lever acts to compress both limbs. Split cable ends are attached to the ends of each axle, countering limb twist. Bowstring midpoint is at or near the nock point, so the nock point is not substantially altered by string stretch. A great benefit of one embodiment is that the limb to limb cable is one length, so that if there is cable stretch each end of the cable will tension adjust equally. Therefore both modules maintain an equal degree of rotation and the nock point doesn't move. The module to lever lengths are only half as long as the cable lengths of other bows, which means string stretch will affect nock position only half as much. By using separate bowstring grooves and cable grooves of varying shapes, one may choose a desired force draw curve, nock travel, and draw length. Furthermore, by using a larger bowstring groove to unreel a desired amount of bowstring and a smaller cable groove wrapping a smaller amount of cable, a shorter lever may be utilized with less mass, and less obtrusive handling of the bow.
[0009]Varying the location of the lever cable pegs, or the points where the lever starts or stops will result in varying the force draw curve and the amount of letoff. The cable groove being axially concentric will provide no letoff. The cable groove with a decreasing radius may provide all or part of letoff. The lever may provide no, part, or all of letoff depending on the degree of rotation.
[0010]As the lever approaches a vertical position the angles of pull from the limbs to the lever are such that the limb tension is pulling against the lever axle so that a letoff of tension will occur to the bowstring. Thus many combinations of the shape of the bowstring groove, the shape of the cable groove, lever peg position and lever angle are possible to effect a desired force draw curve and holding weight.
[0011]While conventional draw stops may be used, novel improved draw stops are utilized to stop the lever rotation. A protrusion of the lever bracket is positioned so that the lever contacts the protrusion and stops, with no more bowstring reeling off either module. An adjustable draw stop is provided by means of a screw protrusion. Adjusting the screw in and out infinitely varies the position the lever stops for draw length adjustment as the lever contacts the head of the screw. Alternately a draw stop is provided by a protrusion of the lever that contacts the bracket, stopping the lever and stopping bowstring from being unreeled. The protrusion may also be an adjustable screw rotated in and out to vary the point of contact with the lever. Screws with differing head widths will also vary the lever contact and change draw length and letoff.
[0012]An additional benefit is that the lever is offset to function as a cable guard, allowing the arrow to pass by the cables. This arrangement is superior to common cable guards on the market where cables ride on rods or wheels, since there is less friction with the cables simply pulling on the lever.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0013]FIG. 1 is a view in side elevation of one embodiment of the compound bow of this invention.
[0014]FIG. 2 is a view in side elevation of a modified form of FIG. 1;
[0015]FIG. 3 is a modified form of the embodiment shown in FIG. 2;
[0016]FIG. 4 is yet another embodiment of compound bow of this invention;
[0017]FIG. 5 is an embodiment in which eccentric cams employed;
[0018]FIG. 6 is a modification of the compound bow shown in FIG. 5;
[0019]FIG. 7 is a detailed view in side elevation of the lever arrangement;
[0020]FIG. 8 is a view in side elevation of an enlarged detailed view of another lever arrangement;
[0021]FIG. 9 is an enlarged detailed view in side elevation of still another lever arrangement;
[0022]FIG. 10 is an enlarged detailed view in side elevation, showing a lever arrangement with a stop;
[0023]FIG. 11 is another view in side elevation somewhat enlarged, showing a lever arrangement, with a stop differently positioned from the stop in FIG. 10; and
[0024]FIG. 12 is a view in side elevation of another lever, only this one carrying a stop.
[0025]Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026]This is a brief description of the preferred embodiment:
[0027]The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
[0028]As shown in FIG. 1, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Wheel 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around wheel 6 and is attached at anchor point 13. Cable 14 extends up to round cable groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to round cable groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down to anchor point 23 on lever 8. Cable 24 is attached to axle 7 and extends up to anchor point 25 on lever 8.
[0029]As shown in FIG. 2, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Wheel 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around wheel 6 and is attached at anchor point 13. Cable 14 extends up to round cable groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to round cable groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down to and around lever peg 23 and around lever peg 24 and attaches to lower axle 7.
[0030]As shown in FIG. 3, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to round cable groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to round cable groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down to and around lever peg 23 and around lever peg 24 and attaches to lower axle 7.
[0031]As shown in FIG. 4, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Wheel 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around wheel 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 and attaches at point 16, and attaches to lever peg 17. Cable 18 extends down to and around cam groove 19 and attaches at point 20, and also extends up to and attaches at lever peg 21. Cable 22 extends up and connects to axle 5 and extends down around lever peg 21 and around lever peg 17 and attaches to axle 7.
[0032]As shown in FIG. 5, limb 1 and limb 2 are connected to bow handle 3. Cam 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around cam 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to cam groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down around lever peg 23 and around lever peg 25 and attaches to axle 7.
[0033]As shown in FIG. 6, limb 1 and limb 2 are connected to bow handle 3. Cam 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around cam 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 and attaches at point 16, and attaches to lever peg 17. Cable 18 extends down to and around cam groove 19 and attaches at point 20, and also extends up to and attaches at lever peg 21. Cable 22 extends up and connects to axle 5 and extends down around lever peg 21 and around lever peg 17 and attaches to axle 7. As shown in FIG. 7, limb 1 and limb 2 are connected to bow handle 3. Cam 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around cam 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 and attaches at point 16, and attaches to lever peg 17. Cable 18 extends down to and around cam groove 19 and attaches at point 20, and also extends up to and attaches at lever peg 21. Cable 22 extends up and connects to axle 5, and extends down around lever peg 23 and around lever peg 25.
[0034]As shown in FIG. 8, lever 49 rotates around bearing 50, which is supported by bracket 51. Cable 52 extends up around lever peg 53 and attaches to lever peg 4. Cable 55 extends down around lever peg 56 and attaches to lever peg 57. Cable 58 extends down around lever peg 59 and around lever peg 60.
[0035]As shown in FIG. 9, lever 67 rotates around bearing 68 which is supported by bracket 69. Cable 70 extends up around lever peg 71 and attaches to lever peg 72. Cable 73 extends down around lever peg 74 and attaches to lever peg 75. Cable 76 extends down around lever peg 77 and attaches to lever peg 78. Cable 79 extends up around lever peg 80 and attaches to lever peg 81.
[0036]As shown in FIG. 10, lever 85 rotates around axle 86 which is supported by bracket 87. Cable 88 extends up around lever peg 89 and attaches to lever peg 90. Cable 91 extends down around lever peg 92 and attaches to lever peg 93. Cable 94 extends down around lever peg 95 and attaches to lever peg 96. Cable 97 extends up around lever peg 98 and attaches to lever peg 99. Draw stop screw 100 attaches to lever bracket 87.
[0037]As shown in FIG. 11, lever 85 rotates around axle 86 which is supported by bracket 87. Cable 88 extends up around lever peg 89 and attaches to lever peg 90. Cable 91 extends down around lever peg 92 and attaches to lever peg 93. Cable 94 extends down around lever peg 95 and attaches to lever peg 96. Cable 97 extends up around lever peg 98 and attaches to lever peg 99. Draw stop screw 100 attaches to lever bracket 87.
[0038]As shown in FIG. 12, lever 85 rotates around axle 86 which is supported by bracket 87. Cable 88 extends up around lever peg 89 and attaches to lever peg 90. Cable 91 extends down around lever peg 92 and attaches to lever peg 93. Cable 94 extends down around lever peg 95 and attaches to lever peg 96. Cable 97 extends up around lever peg 98 and attaches to lever peg 99. Draw stop screw 100 attaches to lever 85.
[0039]In addition to the specific embodiments claimed, the invention is also directed to other embodiments having any possible combination of the invented claims below. For instance many module shapes or draw stops or cable attachments or such may be employed with the invented claims. The lever may be located in the center of the handle, or above or below center. The lever may be attached directly to the bow in lieu of a bracket. The lever may be located any distance from the bow. The lever may have any shape, and an axle may be used alone or with bearings. The cable pegs may be integral to the lever, or be modular such as screws. The pegs may be arranged symmetrically in relation to the axle, or asymmetrical to effect a desired nock travel or force draw curve. Limb to limb cable pegs may be adjusted laterally from lever axle to vary draw force, and lever pegs for module cables may be adjusted laterally to adjust draw length. While the preferred embodiment has split cable ends attached to the module axles outside of the limbs, other arrangements such as the split cable attached inside the limbs to the axle or a single cable attached to the axle may be utilized.
[0040]In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
Claims:
1. a.) An archery bow having a handle, a first and second limb attached to
ends of said handle,b.) rotating modules mounted on ends of said limbs,
said rotating modules having multiple grooves,c.) a bowstring attached to
said modules,d.) a rotatable lever mounted on a support extending from
said handle between said rotating modules, ande.) a cable extending from
one limb to the other limb, said cable means extending between said
limbs, being acted on by said lever when drawing said bow to compress
said limbs.
2. The bow of claim 1 wherein the multiple grooves are concentric about axles of said modules.
3. The bow of claim 1 wherein the multiple grooves are eccentric about axles of said modules.
4. The bow of claim 1 wherein the multiple grooves consist of one concentric groove and one eccentric groove.
5. The bow of claim 1 wherein the multiple grooves consist of one concentric and one cam groove.
6. The bow of claim 1 wherein the multiple grooves consist of one eccentric and one cam groove.
7. The bow of claim 1 wherein the multiple grooves consist of two cam grooves.
8. The bow of claim 1 wherein said cable extending from one limb to the other is attached to axles of modules on top and bottom limbs.
9. The bow of claim 1 wherein said cable extending from one limb to the other is split and attaches to ends of axles of modules outside the limbs.
10. The bow of claim 1 wherein said cable means is routed around pegs on said lever.
11. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves, andc.) a bowstring attached to said modules.d) a cable attached to a module of one limb and extending to and attaching to said lever; and a second cable attaching to module of second limb and extending to and attaching to said lever.
12. The bow of claim 1 wherein said lever is positioned at the midpoint between said modules.
13. The bow of claim 1 wherein said lever is positioned away from the midpoint between said modules.
14. The bow of claim 1 wherein modules vary the leverage applied to the lever compressing the limbs so that peak draw weight is held through a distance of the draw.
15. The bow of claim 1 wherein modules spool bowstring and cables at a rate coupled with the leverage applied to the lever compressing the limbs so that nock travel is straight and level.
16. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves,c.) a bowstring attached to said modules,d.) a rotatable lever mounted on a support extending from said handle between said rotating modules,e.) first cable means extending from one limb to said lever,f.) second cable means extending from second limb to said lever,g.) third cable means attached to the module of one limb and extending to and attaching to said lever, andh.) fourth cable means attached to the module of said second limb and extending to and attaching to said lever.
17. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves,c) a bowstring attached to said modules,d.) a rotatable lever mounted on a support extending from said handle,e.) first cable means extending from one limb to said lever is split and attaches to axles of said modulesf.) second cable means extending from said second limb to said lever, said second cable means being split and attaching to axles of said modules,g.) third cable means attached to the module of one limb and extending to and attaching to said lever, andh.) fourth cable means attached to the module of said second limb and extending to and attaching to said lever.
18. The bow of claim 11 wherein cable means extending from said limbs to said lever is split and attaches to axles of said modules.
19. a.) An archery bow having a handle, a first and second limb attached to the ends of said handle,b.) rotating modules mounted on the ends of said limbs, said rotating modules having multiple grooves,c.) a bowstring attached to said modules,d.) a rotatable lever mounted on a support extending from said handle between said rotating modules,e.) cable means extending between said limbs being acted on by said lever when drawing bow to compress said limbs, andf.) draw stop means prevents movement of said lever
20. The bow of claim 19 wherein draw stop means is an integral protrusion of said lever support.
21. The bow of claim 19 wherein draw stop means is a protrusion attached to said lever support.
22. The bow of claim 21 wherein said protrusion is a screw.
23. The bow of claim 19 wherein said draw stop means is an integral protrusion of said lever.
24. The bow of claim 19 wherein said draw stop means is a protrusion attached to said lever.
25. The bow of claim 24 wherein said protrusion is a screw.
Description:
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001]Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002]Not Applicable.
BACKGROUND OF THE INVENTION
[0003]Early bows consisted of a simple stick with a string attached to each end. In 1969 compound bow U.S. Pat. No. 3,486,495 was granted to Holless Allen. By providing eccentric leverage modules on the end of limbs with operating cabling, the force draw curve of the Allen compound bow could be manipulated to store more energy during the draw cycle, firing a faster arrow and lessen the holding weight at full draw, allowing better aiming. By pulling on the bowstring it was unspooled from the modules, while cabling pulling on the opposing limbs was spooled on the modules. An accuracy problem was inherent in the design as it was difficult, because of manufacturing differences and stretch resulting in unequal lengths of cable, to keep consistent amounts of bowstring unspooled from each module on the limb tips. Thus the nock point would move from its previous path, resulting in an arrow launch different from that which the bow was originally tuned and sighted for, resulting in a loss of accuracy. The need existed for a bow whose nock travel will not be substantially affected by string stretch.
[0004]An additional problem is that one cam could move independently from another at the end of the draw. Thus there would be an inconsistent shift in nock travel at the string release. The dual feed Single Cam bow was invented to deal with the synchronization problem. However, since the midpoint of the bow string was at the idler, there were uneven lengths on opposing sides of the nock point, which resulted in nock movement with string stretch. Further, since the cam limb had no wide cable yoke equalizing pull on the outside of the limb tips, the angle of the cable from the cable guard caused the limb to twist as the bow was drawn and released, stressing the limb and laterally affecting nock travel.
[0005]Recently bows have become popular with cables attaching to the cams to synchronize the cams. However, again by having no wide cable yokes outside the limb tips they are undesirably twisted.
[0006]Thus there exists a need for a compound bow that is synchronized, has more consistent nock travel in case there is string stretch, does not have extreme limb twist affecting nock travel and limb durability, and has a solid draw stop where no bowstring can reel off either module at full draw.
[0007]The closest prior art I have found is from archeryhistory.com, compounds, onecam bows. In this design, the bow is very long with idlers instead of multiple groove modules. Multiple groove modules allow desirable short axle to axle bows, smaller, lighter lever, draw length adjustment, greater energy storage and speed, straight level more accurate nock travel and synchronized cams.
BRIEF SUMMARY OF THE INVENTION
[0008]It is an object of the current invention to provide a compound bow with synchronized cams whose effective cable lengths remain closely matched resulting in consistent nock travel and superior accuracy. The present invention comprises a handle portion, an upper and lower limb supported by the handle portion, and a rotatable synchronizing lever supported by an arm attached to the bow handle. A first rotatable module with a bowstring groove and a cable groove is mounted on the top limb for rotation about an axle. A second rotatable module with a bowstring groove and a cable groove is mounted on the bottom limb for rotation about a second axle. Upon pulling a bowstring attached to the rotatable modules, cables attached to the modules pull on said lever located between the modules. The lever acts upon a cable or cables to pull and compress the limbs. Rotatable modules are thus synchronized since cabling from either module pulling on the lever acts to compress both limbs. Split cable ends are attached to the ends of each axle, countering limb twist. Bowstring midpoint is at or near the nock point, so the nock point is not substantially altered by string stretch. A great benefit of one embodiment is that the limb to limb cable is one length, so that if there is cable stretch each end of the cable will tension adjust equally. Therefore both modules maintain an equal degree of rotation and the nock point doesn't move. The module to lever lengths are only half as long as the cable lengths of other bows, which means string stretch will affect nock position only half as much. By using separate bowstring grooves and cable grooves of varying shapes, one may choose a desired force draw curve, nock travel, and draw length. Furthermore, by using a larger bowstring groove to unreel a desired amount of bowstring and a smaller cable groove wrapping a smaller amount of cable, a shorter lever may be utilized with less mass, and less obtrusive handling of the bow.
[0009]Varying the location of the lever cable pegs, or the points where the lever starts or stops will result in varying the force draw curve and the amount of letoff. The cable groove being axially concentric will provide no letoff. The cable groove with a decreasing radius may provide all or part of letoff. The lever may provide no, part, or all of letoff depending on the degree of rotation.
[0010]As the lever approaches a vertical position the angles of pull from the limbs to the lever are such that the limb tension is pulling against the lever axle so that a letoff of tension will occur to the bowstring. Thus many combinations of the shape of the bowstring groove, the shape of the cable groove, lever peg position and lever angle are possible to effect a desired force draw curve and holding weight.
[0011]While conventional draw stops may be used, novel improved draw stops are utilized to stop the lever rotation. A protrusion of the lever bracket is positioned so that the lever contacts the protrusion and stops, with no more bowstring reeling off either module. An adjustable draw stop is provided by means of a screw protrusion. Adjusting the screw in and out infinitely varies the position the lever stops for draw length adjustment as the lever contacts the head of the screw. Alternately a draw stop is provided by a protrusion of the lever that contacts the bracket, stopping the lever and stopping bowstring from being unreeled. The protrusion may also be an adjustable screw rotated in and out to vary the point of contact with the lever. Screws with differing head widths will also vary the lever contact and change draw length and letoff.
[0012]An additional benefit is that the lever is offset to function as a cable guard, allowing the arrow to pass by the cables. This arrangement is superior to common cable guards on the market where cables ride on rods or wheels, since there is less friction with the cables simply pulling on the lever.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0013]FIG. 1 is a view in side elevation of one embodiment of the compound bow of this invention.
[0014]FIG. 2 is a view in side elevation of a modified form of FIG. 1;
[0015]FIG. 3 is a modified form of the embodiment shown in FIG. 2;
[0016]FIG. 4 is yet another embodiment of compound bow of this invention;
[0017]FIG. 5 is an embodiment in which eccentric cams employed;
[0018]FIG. 6 is a modification of the compound bow shown in FIG. 5;
[0019]FIG. 7 is a detailed view in side elevation of the lever arrangement;
[0020]FIG. 8 is a view in side elevation of an enlarged detailed view of another lever arrangement;
[0021]FIG. 9 is an enlarged detailed view in side elevation of still another lever arrangement;
[0022]FIG. 10 is an enlarged detailed view in side elevation, showing a lever arrangement with a stop;
[0023]FIG. 11 is another view in side elevation somewhat enlarged, showing a lever arrangement, with a stop differently positioned from the stop in FIG. 10; and
[0024]FIG. 12 is a view in side elevation of another lever, only this one carrying a stop.
[0025]Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026]This is a brief description of the preferred embodiment:
[0027]The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
[0028]As shown in FIG. 1, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Wheel 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around wheel 6 and is attached at anchor point 13. Cable 14 extends up to round cable groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to round cable groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down to anchor point 23 on lever 8. Cable 24 is attached to axle 7 and extends up to anchor point 25 on lever 8.
[0029]As shown in FIG. 2, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Wheel 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around wheel 6 and is attached at anchor point 13. Cable 14 extends up to round cable groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to round cable groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down to and around lever peg 23 and around lever peg 24 and attaches to lower axle 7.
[0030]As shown in FIG. 3, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to round cable groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to round cable groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down to and around lever peg 23 and around lever peg 24 and attaches to lower axle 7.
[0031]As shown in FIG. 4, limb 1 and limb 2 are connected to bow handle 3. Wheel 4 rotates on axle 5 which is connected to limb 1. Wheel 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around wheel 4 and is attached at anchor point 12. Bow string 11 also rotates around wheel 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 and attaches at point 16, and attaches to lever peg 17. Cable 18 extends down to and around cam groove 19 and attaches at point 20, and also extends up to and attaches at lever peg 21. Cable 22 extends up and connects to axle 5 and extends down around lever peg 21 and around lever peg 17 and attaches to axle 7.
[0032]As shown in FIG. 5, limb 1 and limb 2 are connected to bow handle 3. Cam 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around cam 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 at anchor point 16, and also extends down to anchor point 17 of lever 8. Cable 18 extends up to cam groove 19 at anchor point 20, and also extends up to anchor point 21 of lever 8. Cable 22 extends up and connects to axle 5, and extends down around lever peg 23 and around lever peg 25 and attaches to axle 7.
[0033]As shown in FIG. 6, limb 1 and limb 2 are connected to bow handle 3. Cam 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around cam 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 and attaches at point 16, and attaches to lever peg 17. Cable 18 extends down to and around cam groove 19 and attaches at point 20, and also extends up to and attaches at lever peg 21. Cable 22 extends up and connects to axle 5 and extends down around lever peg 21 and around lever peg 17 and attaches to axle 7. As shown in FIG. 7, limb 1 and limb 2 are connected to bow handle 3. Cam 4 rotates on axle 5 which is connected to limb 1. Cam 6 rotates on axle 7 which is connected to limb 2. Lever 8 rotates on axle 9 which is attached to bracket 10 which is attached to bow handle 3. Bow string 11 routes around cam 4 and is attached at anchor point 12. Bow string 11 also rotates around cam 6 and is attached at anchor point 13. Cable 14 extends up to cam groove 15 and attaches at point 16, and attaches to lever peg 17. Cable 18 extends down to and around cam groove 19 and attaches at point 20, and also extends up to and attaches at lever peg 21. Cable 22 extends up and connects to axle 5, and extends down around lever peg 23 and around lever peg 25.
[0034]As shown in FIG. 8, lever 49 rotates around bearing 50, which is supported by bracket 51. Cable 52 extends up around lever peg 53 and attaches to lever peg 4. Cable 55 extends down around lever peg 56 and attaches to lever peg 57. Cable 58 extends down around lever peg 59 and around lever peg 60.
[0035]As shown in FIG. 9, lever 67 rotates around bearing 68 which is supported by bracket 69. Cable 70 extends up around lever peg 71 and attaches to lever peg 72. Cable 73 extends down around lever peg 74 and attaches to lever peg 75. Cable 76 extends down around lever peg 77 and attaches to lever peg 78. Cable 79 extends up around lever peg 80 and attaches to lever peg 81.
[0036]As shown in FIG. 10, lever 85 rotates around axle 86 which is supported by bracket 87. Cable 88 extends up around lever peg 89 and attaches to lever peg 90. Cable 91 extends down around lever peg 92 and attaches to lever peg 93. Cable 94 extends down around lever peg 95 and attaches to lever peg 96. Cable 97 extends up around lever peg 98 and attaches to lever peg 99. Draw stop screw 100 attaches to lever bracket 87.
[0037]As shown in FIG. 11, lever 85 rotates around axle 86 which is supported by bracket 87. Cable 88 extends up around lever peg 89 and attaches to lever peg 90. Cable 91 extends down around lever peg 92 and attaches to lever peg 93. Cable 94 extends down around lever peg 95 and attaches to lever peg 96. Cable 97 extends up around lever peg 98 and attaches to lever peg 99. Draw stop screw 100 attaches to lever bracket 87.
[0038]As shown in FIG. 12, lever 85 rotates around axle 86 which is supported by bracket 87. Cable 88 extends up around lever peg 89 and attaches to lever peg 90. Cable 91 extends down around lever peg 92 and attaches to lever peg 93. Cable 94 extends down around lever peg 95 and attaches to lever peg 96. Cable 97 extends up around lever peg 98 and attaches to lever peg 99. Draw stop screw 100 attaches to lever 85.
[0039]In addition to the specific embodiments claimed, the invention is also directed to other embodiments having any possible combination of the invented claims below. For instance many module shapes or draw stops or cable attachments or such may be employed with the invented claims. The lever may be located in the center of the handle, or above or below center. The lever may be attached directly to the bow in lieu of a bracket. The lever may be located any distance from the bow. The lever may have any shape, and an axle may be used alone or with bearings. The cable pegs may be integral to the lever, or be modular such as screws. The pegs may be arranged symmetrically in relation to the axle, or asymmetrical to effect a desired nock travel or force draw curve. Limb to limb cable pegs may be adjusted laterally from lever axle to vary draw force, and lever pegs for module cables may be adjusted laterally to adjust draw length. While the preferred embodiment has split cable ends attached to the module axles outside of the limbs, other arrangements such as the split cable attached inside the limbs to the axle or a single cable attached to the axle may be utilized.
[0040]In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
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