Archery bow cam and related method of use
11598601 · 2023-03-07
Assignee
Inventors
Cpc classification
International classification
Abstract
An archery bow is provided including a cam rotatable about an axis, a bowstring disposed in a bowstring track of the cam having a plane of rotation perpendicular to the axis, and a power cable that is displaced along the axis toward the plane of rotation to concentrate a force of the power cable near a force of the bowstring along the axis to inhibit twisting of a limb, when the bow is drawn. A related method of use is provided.
Claims
1. An archery bow comprising: a riser; a first limb and a second limb joined with the riser; a first cam rotatably mounted to the first limb about a first axis, the first cam comprising: a first bowstring track having a first plane of rotation perpendicular to the first axis; a first power cable take up track extending in a direction laterally away at a first angle from the first plane of rotation of the first bowstring track; a second cam rotatably mounted to the second limb about a second axis, the second cam comprising: a second bowstring track having a second plane of rotation perpendicular to the second axis; a second power cable take up track extending in a direction laterally away at a second angle from the second plane of rotation of the second bowstring track; a bowstring received in first and second bowstring tracks and moveable in a bowstring plane, the bowstring configured to unwind out from the first and second bowstring tracks when the bowstring is drawn; a first power cable received in the first power cable take up track of the first cam; and a second power cable received in the second power cable take-up track of the second cam, wherein the bowstring is distal and separated from the first power cable and the second power cable, wherein as the archery bow is drawn the first power cable is taken up in the first power cable take up track and displaced along the first axis toward the first plane of rotation of the first bowstring track to concentrate a first force of the first power cable near a first force of the bowstring along the first axis to inhibit twisting of the first limb, wherein as the archery bow is drawn the second power cable is taken up in the second power cable take up track and displaced along the second axis toward the second plane of rotation of the second bowstring track to concentrate a second force of the second power cable near a second force of the bowstring along the second axis to inhibit twisting of the second limb.
2. The archery bow of claim 1, wherein the first power cable take up track transitions toward the first plane of rotation, wherein the second power cable take up track transitions toward the second plane of rotation.
3. The archery bow of claim 1, wherein the first power cable includes an initial power cable contact point contacting the first power cable take up track at a first distance from the first plane of rotation when the archery bow is undrawn, wherein the first power cable includes a subsequent power cable contact point contacting the first power cable take up track at a second distance from the first plane of rotation when the archery bow is drawn, wherein the second distance is less than the first distance so that the subsequent power cable contact point is closer to the first plane of rotation when the bow is drawn.
4. The archery bow of claim 1, wherein the first power cable is displaced along the first axis toward the first plane of rotation of the first bowstring track so that the first power cable intersects the first plane of rotation within a first cam perimeter of the first cam.
5. The archery bow of claim 4, wherein the first power cable intersects the first plane of rotation within a first cam perimeter of the first cam before the archery bow is fully drawn in a fully drawn state, wherein the first power cable moves away from the first plane of rotation so that the first power cable no longer intersects the first plane of rotation when the first cam transitions from the fully drawn state to an undrawn state.
6. The archery bow of claim 1, wherein the first power cable take up track includes a first end of draw part, wherein the first plane of rotation extends through the first bowstring track and through the first end of draw part of the first power cable take up track, wherein the first end of draw part is located between the first axis and the first bowstring track.
7. The archery bow of claim 1, comprising: a first power cable let out track on the first cam, wherein the second power cable extends away from the second cam and is received in the first power cable let out track on the first cam; wherein as the archery bow is drawn the second power cable is let out by the first power cable let out track and displaced along the first axis toward the first plane of rotation of the first bowstring track.
8. The archery bow of claim 1, wherein the first power cable take up track curves around the first axis toward the first plane so that the first power cable is guided toward the first plane as the first power cable is taken up in the first power cable take up track, curving toward the first plane as the bow is drawn.
9. The archery bow of claim 1 comprising: a bowstring anchor projecting from the first cam; a bowstring end of the bowstring being joined with the bowstring anchor; a power cable anchor projecting from the first cam; and a first power cable end of the first power cable being joined with the power cable anchor distal from the bowstring anchor.
10. The archery bow of claim 1, comprising: a first power cable let out track on the first cam, wherein the first power cable take up track transitions a first force from the first power cable therein toward the bowstring plane as the archery bow is drawn, wherein the first power cable let out track transitions a second force from the second power cable therein toward the bowstring plane as the archery bow is drawn.
11. The archery bow of claim 1, comprising: a first centerline of the first limb, wherein the first centerline lays in the bowstring plane, wherein the first plane of rotation is parallel to the bowstring plane.
12. The archery bow of claim 1, comprising: an axle having a center, wherein the first plane of rotation passes through the center.
13. The archery bow of claim 1, a bowstring anchor projecting from the first cam; a bowstring end of the bowstring being joined with the bowstring anchor; a power cable anchor projecting from the first cam; a first power cable end of the first power cable being joined with the power cable anchor distal from the bowstring anchor; a first power cable let out track on the first cam; and a second power cable in the first power cable let out track, wherein the first power cable take up track transitions a first force from the first power cable therein toward the bowstring plane as the archery bow is drawn, wherein the first power cable let out track transitions a second force from the second power cable therein toward the bowstring plane as the archery bow is drawn.
14. An archery bow comprising: a first limb and a second limb; a first cam rotatably mounted to the first limb about a first axis, the first cam comprising: a first bowstring track having a first plane of rotation perpendicular to the first axis; a first power cable take up track extending in a direction angled laterally away from the first plane of rotation of the first bowstring track; a bowstring received in a first bowstring track and moveable in a bowstring plane, the bowstring configured to unwind out from the first bowstring track when the bowstring is drawn; a first power cable received in the first power cable take up track of the first cam; wherein as the archery bow is drawn the first power cable is taken up in the first power cable take up track and displaced along the first axis toward the first plane of rotation of the first bowstring track to move a first force of the first power cable near a first force of the bowstring along the first axis to inhibit twisting of the first limb, wherein the bowstring is distal and separated from the first power cable.
15. The archery bow of claim 14, comprising: a first power cable let out track on the first cam, wherein a second power cable is received in the first power cable let out track on the first cam; wherein as the archery bow is drawn the second power cable is let out by the first power cable let out track and displaced along the first axis toward the first plane of rotation of the first bowstring track.
16. The archery bow of claim 14, comprising: a first power cable let out track on the first cam, wherein the first power cable take up track is located between the first power cable let out track and the first bowstring track along the first axis, wherein the first power cable take up track transitions a first force from the first power cable toward the bowstring plane, wherein the first power cable let out track transitions a second force from the second power cable toward the bowstring plane.
17. The archery bow of claim 14, wherein the first power cable intersects the first plane of rotation within a first cam perimeter of the first cam before the archery bow is fully drawn.
18. The archery bow of claim 14 comprising: a bowstring anchor projecting from the first cam; a bowstring end of the bowstring being joined with the bowstring anchor; a power cable anchor projecting from the first cam; and a first power cable end of the first power cable being joined with the power cable anchor distal from the bowstring anchor.
19. The archery bow of claim 14, comprising: a first power cable let out track on the first cam; and a second power cable in the first power cable let out track, wherein the first power cable take up track transitions a first force from the first power cable therein toward the bowstring plane as the archery bow is drawn, wherein the first power cable let out track transitions a second force from the second power cable therein toward the bowstring plane as the archery bow is drawn.
20. The archery bow of claim 14, comprising: a first centerline of the first limb; an axle having a center; wherein the first centerline lays in the bowstring plane, wherein the first plane of rotation is parallel to the bowstring plane, wherein the first plane of rotation passes through the center.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE CURRENT EMBODIMENTS
(16) A compound archery bow including a cam system and a bowstring in accordance with a current embodiment is illustrated in
(17) Although the current embodiment of
(18) As used herein, a “cam” refers to a cam, a pulley, and/or an eccentric, whether a modular, removable part, or an integral part of a cam, for use with an archery bow. As used herein, “inhibit” refers to preventing, impairing and/or reducing a certain event, action, result, force, torque, twist and/or activity. As used herein, a “track” refers to a structural element that is adapted to guide or accommodate a portion of a bowstring or power cable within or adjacent the element, and can be in the form of a groove, a recess, a slot, pins or posts extending from or defined by a surface or element. When in the form of a groove or recess, that element can be defined by a part of a cam, and can be of virtually any geometric cross section, for example, partially or fully semi-circular, rounded, triangular, rectangular, square, polygonal, or combinations of the foregoing.
(19) As used herein, an “axis of rotation”, “first axis of rotation” or “second axis of rotation refers to an axis about which a cam can and/or does rotate, for example, a first axis AX1 or second axis AX2 as shown in
(20) Although not described in detail, the cams herein can include modular elements that provide some level of adjustment of a performance characteristic of a bow, including but not limited to, a particular draw length, draw stop or draw force for the bow. The cams can have secured thereto draw stops, anchors, bearings and other components. The cam components herein can be joined with one another via fasteners such as screws, rivets, welds, and other fastening structures. Alternatively, the cam components can be in the form of a monolithic, continuous single piece structure that includes the cam components and the respective features thereof.
(21) The cams and the respective cam components, for example, the portions that define the bowstring tracks and power cable tracks as described below can be constructed from a rigid metal, polymeric, and/or composite structure, and can have a generally volute peripheral shape. Optionally, the cam assembly can be machined from metal, such as aluminum, magnesium or titanium, metal injection molded, and/or formed from a composite material with suitable properties.
(22) As shown in
(23) As mentioned above, the first 21 and second 31 bowstring tracks can lie and can rotate in the respective first P1 and second P2 planes, which are generally perpendicular to the axes AX1 and AX2 of rotation of the respective cams 20 and 30. Each bowstring track can include respective bowstring let out portions 23, 33, from which the respective first and second bowstring portions 91 and 92 of the bowstring 90 can be let out from when the bow 10 is drawn during a draw cycle. The bowstring let out portions can be contiguous with the remainder of the respective bowstring tracks as shown, or can be segmented or separate from the remainder of the bowstring tracks if desired.
(24) Turning now to
(25) With reference to
(26) The first force F1, second force F2 and third force F3 can simultaneously be exerted on the axis AX1. With the second force F2 and the third force F3 being exerted by the respective first power cable 81 and second power cable 82 offset at distances D2 or D3 respectively, the net result is a moment M1 is exerted on the limb 14 when the bow is in the undrawn state. Because the bow is in the undrawn state, this obviously does not have any effect on nock travel or the location of the bowstring.
(27) With the current embodiments of the archery bow and cam described herein, when or as the archery bow is drawn to the drawn state shown in
(28) Further optionally, the rates at which the respective first and second power cables approach and are displaced toward the first plane P1 can be the same, greater or lesser than one another. When the cam 20 has rotated through optionally at least 20°, at least 30°, at least 40°, at least 50°, at least 60°, at least 70°, at least 80°, at least 90°, at least 100°, at least 110°, at least 120°, at least 130°, at least 140°, at least 150°, at least 160°, at least 170°, at least 180°, at least 200°, at least 225° or at least 250°, the respective power cable take up track 41 and power cable let out track 51 has begun to displace the respective first and second power cables toward the first plane of rotation P1. Before that amount of rotation, the power cable may not have been being displaced substantially toward the plane.
(29) Referring again to
(30) Accordingly, with the concentration of these forces closer to the plane of rotation and/or the centerline 14L of the limb, twisting and/or torque exerted on the limb 14 can be reduced. For example, the moment M2 exerted about the point C2 located in the first plane P1 and along the centerline 14L as shown in
(31) The moment M2 and the respective forces F4 and F5 can create the moment M2 which can change as the cam 20 rotates and the respective power cables 81 and 82 are wound out from and back onto the respective tracks as the cam rotates upon shooting of the bow. For example, as shown in
(32) The change in the moments from the greater moment, M1 to the lesser moment M2 as the first and second power cables 81 and 82 are displaced toward the first plane P1 and the centerline axis AX1 also can be understood referring to the distances of the forces of the power cables at locations along the first axis AX1. For example, as shown in
(33) Again, the movement of the forces exerted by the first and second power cables is affected by and provided by the movement of the respective power cables 81 and 82 being displaced toward the first plane P1 which optionally can lay along the first centerline 14L of the limb 14. It will also be appreciated that with the lesser moment M2 being exerted on the cam 20 and 30 as the cams rotate certain amounts from the drawn state to the undrawn state during a shot, there is less cam lean and limb twist, which in turn results in more consistent and linear nock travel. This can result in more accurate, consistent and precise trajectories of arrows propelled from the bowstring and bow. It is also contemplated that the configuration of the respective power cable tracks can be constructed so that the moment M2 is maintained for a substantial portion of the release cycle such that that moment M2 does not substantially increase until after the nock of an arrow has disengaged the knock of the bowstring. Thus, any effect of the greater moment M1 on the cam 20, 30 and/or the respective bowstring or power cables would not significantly affect the arrow because it would have already disengaged the bowstring.
(34) Optionally, when the first power cable 81 is being taken up by the first power cable take up track 41, it can move a greater amount toward the first plane P1 and centerline 14L than the second power cable 82 when being let out by the first power cable let out track 51. For example, the first power cable 81 and its associated force F2 in the undrawn state can transition to from the distance D2 to the distance D4 away from the first plane P1. The second power cable and its force F3 can transition from a distance D3 to a distance D5 closer to the first plane P1. The difference between D4 minus D2 can be greater than the difference between D5 minus D3. In some cases, the distance moved or displaced toward the first plane P1 by the first power cable 81 and its associated force on the first axis AX1 can be optionally at least 5%, at least 10%, at least 15%, at least 20%, at least 25% greater than the distance moved closer to the first plane P1 by the second power cable 82 and its associated forces on the first axis AX1. In other applications with other cam configurations, the distances moved by the first power cable and second power cable, and their attendant forces on the first axis AX1 can be equal or reversed.
(35) With further reference to
(36) In the drawn condition shown in
(37) In other cases, as shown, these components can intersect and/or pass through the plane by certain amount, generally crossing from one side of the first plane to an opposing second side of the first plane as the archery bow is drawn. As a result, the first power cable 81 is guided and deflected or displaced toward and/or through the first plane P1 by the first power cable take up track. It will be appreciated that as the first power cable is in the condition shown in the when the bow is drawn as shown in
(38) As shown in
(39) Returning to
(40) Optionally, as shown in
(41) The cable guard 18 can effectively exert a force on the cable 81 to hold or direct it away from the first plane P1 at a predetermined angle A7 at the location 81P as the bow is drawn. This can be better understood with reference to
(42) Due to the overlap of the bowstring and the bowstring track over the cable 81 and cable track 41, the cable 81 can be angled outward at angle A7 relative to the plane P1 so that the cable has enough clearance CL at the outer perimeter 22 of the cam to clear the cam at all times when the bow is drawn, shot or undrawn. With this clearance CL, the cable 81 will not touch the cam 20 along its parts that are outside the track 41, even when parts of the power cable 81 are under the bowstring and/or bowstring track, or generally between the axis and the bowstring and/or bowstring track as shown in
(43) The angle A7 can be produced via the cable guard 18, which can exert a force LF on the cable 81 (and cable 82, although not shown) to urge the part of the cable outward, distal from the cams, away from the planes P1 (and P2, although not shown). When the cable guard exerts this force LF and produces the angle A7 in the cable at the point 81P, the cable is enabled to fit under the bowstring track/bowstring, much closer to the plane P1, without concern of other parts of the cable rubbing on other parts to the cam, because the clearance CL is created. Optionally, in some alternative applications without the cable guard, or some other element exerting a force LF to produce the angle A7, the cable distal from the point 81P might interfere with or rub on other parts of the cam. Further optionally, although a cable guard of a compound archery bow is shown as producing the force to create the angle A7, it is contemplated that such a cable guard can alternatively be replaced or substituted with a barrel, a rail or other guide on a crossbow or other archery bow that uses cables.
(44) Movement of the power cables relative to the plane P1 can be further understood with reference to
(45) With reference to
(46) Optionally, where the second power cable last touches the first power cable let out track 51 at the last contact portion 82D, the power cable section 82S that extends to the second cam 30 transitions from that last contact portion 82D at an angle A4 relative to the track portion 82T, which remains in the first power cable let out track. 51. This angle A4 can be an acute angle and optionally can be less than the angle A3 mentioned above.
(47) Turning now to
(48) Generally, the first power cable take up track can extend in a direction perpendicular to the plane of rotation of the first bowstring track 21. As illustrated in
(49) The first power cable take up track 41 optionally can include or be in the form of a U- or V-shaped channel or groove that extends around a portion of the first axis AX1, optionally in an eccentric and/or volute configuration. The first section 43 of the track can be generally U-shaped and of a slightly wider width W2 then the width W81 of the first power cable 81. This first section as mentioned above can transition to a second section 44 where the track 41 transitions toward and closer to the first plane P1 so that it can displace the power cable toward that first plane P1 as the bow is drawn. The first section 43 can include first and second side walls 43A and 43B that form the upwardly extending portions of the channel. These sidewalls can be symmetric relative to one another.
(50) As shown in
(51) With further reference to
(52) Optionally, as further shown in
(53) The first power cable take up track 41 can include the first end of draw part or portion 43E. This first end of draw part 43E can be the last part of the track that contacts the first power cable and the subsequent contact point 81P of the power cable when the bow is fully drawn. Optionally, the first plane of rotation P1 can extend through the first bowstring track 43 and through the first end of draw part 43E, or otherwise intersect or cross the first end of draw part of the track. This first end of draw part 43 also can be located between the first axis AX1 and the first bowstring track 21 along a radial line emanating from the axis AX1.
(54) Returning to
(55) A method of using the archery bow and the respective cams 20, 30 thereof will now be described in further detail with reference to
(56) With reference to
(57) As the bow 10 is initially drawn as shown in
(58) As the bow 10 is further drawn as shown in
(59) The bow 10 can continue to be drawn to the drawn state as shown in
(60) The first power cable 81 also can be partially or entirely disposed below the lateral side surface 27 of the cam 20, which is why a substantial portion of it is shown in broken lines in the view in
(61) After the bow is fully drawn, it can be shot. As a result, and as mentioned above, the moment and torque exerted by the power cables during the initial part of the shot cycle can remain low, so that the cam does not lean much then, and so that nock travel remains level and consistent.
(62) Directional terms, such as “vertical,” “horizontal,” “top,” “bottom,” “upper,” “lower,” “inner,” “inwardly,” “outer” and “outwardly,” are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. The use of directional terms should not be interpreted to limit the invention to any specific orientation(s).
(63) In addition, when a component, part or layer is referred to as being “joined with,” “on,” “engaged with,” “adhered to,” “secured to,” or “coupled to” another component, part or layer, it may be directly joined with, on, engaged with, adhered to, secured to, or coupled to the other component, part or layer, or any number of intervening components, parts or layers may be present. In contrast, when an element is referred to as being “directly joined with,” “directly on,” “directly engaged with,” “directly adhered to,” “directly secured to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between components, layers and parts should be interpreted in a like manner, such as “adjacent” versus “directly adjacent” and similar words. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
(64) The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular. Any reference to claim elements as “at least one of X, Y and Z” is meant to include any one of X, Y or Z individually, any combination of X, Y and Z, for example, X, Y, Z; X, Y; X, Z; Y, Z, and/or any other possible combination together or alone of those elements, noting that the same is open ended and can include other elements.