ARCHERY BOW CAM ROTATION ASSIST DEVICE

Abstract

An archery bow is provided including a cam body rotatably joined with a limb and a cam rotation assist device engaging a portion of the cam body so as to urge rotation of the cam body independent of the limb. With the action thereon by the cam rotation assist device, the cam body rotates faster upon initial rotation during a shot cycle when the bow is shot than the cam body otherwise would rotate if the cam rotation assist device was absent. This can reduce the effect of inertia on the cam, and can improve dynamic efficiency of the bow. The rotation assist device can be in the form of a mini limb, a coil spring, programmable magnets and other components that can urge cam rotation of the cam body. The cam body can include a draw stop that engages the mini limb. Related methods are provided.

Description

BACKGROUND OF THE INVENTION

The present invention relates to archery products, and more particularly to cam rotation assist devices that increase the efficiency of an archery bow by urging rotation of one or more cams of the archery bow.

Conventional compound and crossbow archery bows include a bowstring and a set of power cables that transfer energy from the limbs and cams, eccentrics or pulleys (which are all referred to generally as “cams” herein) of the bow to the bowstring, and thus to an arrow shot from the bow. The cables and bowstring are strung from a cam on one limb to a cam on another limb. The function of the cams is to provide a mechanical advantage so that energy imparted to the arrow is a multiple of that required of an archer to draw the bow.

Generally, there are single cam systems and dual cam systems, with various configurations of each. A single cam system usually includes a single cam mounted on one limb and a single track pulley mounted on the other limb of the bow. One dual cam system includes two cams, each mounted on opposing limbs of a bow. Two cables and a single bowstring are strung between both cams; however, one end of each cable is yoked to an axle upon which a cam rotates. Another variant of the dual cam system, often referred to as a “cam and a half”, has one cable connected to a yoke at one end of that cable, and another cable connected to both cams.

Yet another innovative cam system includes the parallel cam, offered by G5 Outdoors, LLC, under the Prime brand. The parallel cam system includes first and second bowstring tracks positioned on opposite sides of a power cable track. The power cable track can be centered within the cam assembly, aligned with a balance point of the cam assembly, and centered relative to an axis about which the cam assembly rotates to balance forces exerted on the cam by the bowstring and/or cable during a draw cycle.

Regardless of the type of cam system, they all work somewhat similarly on bows. For example, when an archer draws the bow from an undrawn state to a drawn state, the bowstring rotates the cams rearward, and the force and energy applied by the archer to draw the bow is transferred to the limbs, typically bending the limbs so that they effectively store energy in their bent or flexed configuration. When the archer releases the bowstring, the energy stored in the limbs assists in rotating the cams and propelling the bowstring to its original position in an undrawn state.

In many conventional cam systems, the cams of a bow do not rotate quickly enough to the pre-firing condition or undrawn state. This decreases the efficiency of the bow and otherwise reduces its performance.

SUMMARY OF THE INVENTION

An archery bow including a cam rotation assist device is provided to facilitate rotation of a cam of the bow independently and/or in addition to rotation imparted to the cam via movement of a respective limb and/or strings of the archery bow. By assisting the cam to rotate faster with the cam rotation assist device, the cam can rotate more in unison with the limb, and increase bow efficiency and/or enhance arrow speed.

In one embodiment, the archery bow can include a rotatable cam (which as used herein refers to a cam, an eccentric and/or a pulley) that includes a cam body adapted to rotate upon drawing of the archery bow. The cam body can include a cam projection that extends laterally outwardly therefrom. The archery bow also can include a limb portion that extends adjacent the cam. A rotation assist device can be joined with the limb portion in a pathway of cam projection. The rotation assist device can engage the cam projection and can urge the cam to rotate in a preselected direction, for example, clockwise and/or counterclockwise.

In another embodiment, the rotation assist device can be in the form of a mini limb. The mini limb can be constructed from metal, composites, polymers and/or other materials. The mini limb can be at least partially curved and/or angled, with a contact portion adapted to engage the cam projection.

In still another embodiment, the mini limb can be joined with the limb portion and disposed laterally relative to the cam body. The mini limb can be positioned so that it engages the cam projection for least a portion of the cam projection's movement along the pathway of the cam projection. In some cases, the pathway of the cam projection can be a circular pathway about an axle or axis of rotation of the cam body. In some cases, the mini limb can engage the cam projection for optionally 0° to 360°, further optionally 0° to 180°, even further optionally 0° to 90°, and even further optionally 0° to 5°. In other cases, the cam pathway can be an irregular pathway about an axle or axis of rotation of the cam body.

In even another embodiment, the mini limb can bend and/or flex along a portion thereof when the cam projection engages the mini limb as the bow is drawn to the drawn mode. As it bends, the mini limb stores energy therein. When the cam begins to rotate as the bow is shot, and returns to its undrawn state, the stored energy in the mini limbs urges the cam projection faster along its pathway. Thus, with the mini limb urging the cam projection, the cam itself rotates faster as the bow is shot and begins to return to its undrawn state. This, in turn, increases the rotational speed of the cam and dynamic efficiency of the bow in general.

In yet another embodiment, the rotation assist device is configured to engage a portion of the cam and/or a projection extending therefrom to overcome initial inertia and initiate more quickly rotation of the cam when the bow is shot and the limbs of the bow begin to move and translate energy to propel the arrow being shot from the archery bow.

In still yet another embodiment, the rotation assist device in the form of a mini limb can be duplicated on opposing sides of the cam body. Likewise, the cam projection can be duplicated on opposing sides of the cam body. In this manner, two opposing mini limbs can urge rotation of the cam body in a balanced manner about its axis of rotation.

In a further embodiment, the archery bow can include a rotation assist device in the form of a coil spring that is joined with the cam body. For example, a coil spring can be installed about an axle about which the cam body rotates. The coil spring can be joined with the cam body and another component of the archery bow. When the archery bow is drawn, along at least a portion of the draw cycle, the coil spring can be coiled and/or uncoiled to subsequently store energy therein. When the bow is shot, the coil spring can exert its stored energy on the cam body, thereby urging it to rotate faster than the cam body would rotate if the coil spring was not present. This can increase the dynamic efficiency of the bow.

In yet a further embodiment, the rotation assist device in the form of a coil spring can be duplicated on opposing sides of the cam body. In this manner, two opposing coil springs can urge rotation of the cam body in a balanced manner about its axis of rotation.

In even a further embodiment, the rotation assist device can be in the form of programmable magnets. For example, the cam body can include one or more programmable magnets. A portion of the limb or other component adjacent the cam body adjacent and/or along at least a portion of the cam bodies' path of rotation can include a complementary programmable magnet or other magnetic element. When the programmable magnets on the cam body are placed adjacent the complementary programmable magnet or other magnetic element, those magnets can effectively attract and/or repel one another to urge rotation of the cam body. This can have the same dynamic efficiency results as the mini limb and/or coil spring as described above

The archery bow of the current embodiments, with its cam rotation assist device, can exhibit increased efficiency, faster nock travel and faster arrow speeds. Due to the cam rotation assist device, and its ability to assist in rotation of the cam, in some cases the overall weight of the cam can be increased without sacrificing rotational efficiency. In turn, this can improve the structural integrity and strength of the cam.

These and other objects, advantages, and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings.

Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and of being practiced or being carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an archery bow including upper and lower cams with respective cam rotation assist devices;

FIG. 2 is a side view of a cam body and limb with the archery bow in an undrawn state, before a portion of the cam body engages the cam rotation assist device;

FIG. 3 is a side view of the cam body and limb, with the archery bow in a drawn state, and a portion of the cam body engaging the cam rotation assist device;

FIG. 4 is a lower perspective view of the archery bow and in particular the upper cam and the cam rotation assist device, which is in a compressed or flexed state so as to store energy therein;

FIG. 5 is a side view of the cam body and limb, with the archery bow in an undrawn state, before a portion of the cam body engages a first alternative cam rotation assist device;

FIG. 6 is a side view of the cam body and limb with the archery bow in a drawn state, and a portion of the cam body engaging the first alternative cam rotation assist device;

FIG. 7 is a side view of the cam body and limb with the archery bow in an undrawn state, illustrating a second alternative cam rotation assist device in the form of a coil spring;

FIG. 8 is a side view of the cam body and limb with the archery bow in a drawn state, and a portion of the cam body engaging the second alternative cam rotation assist device;

FIG. 9 is a top view of the second alternative cam rotation assist device in the form of the coil spring;

FIG. 10 is a side view of the cam body and limb with the archery bow in an undrawn state, before a third alternative cam rotation assist device, in the form of programmable magnets, is engaged;

FIG. 11 is a side view of the cam body and limb, with the archery bow in a drawn state, with the programmable magnets engaged due to rotation of the cam body; and

FIG. 12 is a is a lower perspective view of the archery bow and in particular the upper cam and the cam rotation assist device, with certain programmable magnets aligned with and repelling one another.

DESCRIPTION OF THE CURRENT EMBODIMENTS

A compound archery bow including one or more cams including a cam rotation assist device in accordance with a current embodiment is illustrated in FIG. 1 and generally designated 10. The cam system can include upper 20 and lower 30 cam bodies or assemblies, which can form a dual cam system on the bow 10. The upper cam body 20 can be mounted to an upper limb 15 and the lower cam assembly 30 can be mounted to the lower limb 14 of the bow 10. The upper and lower limbs can be joined with the riser 16 of the bow, and spaced apart from one another in a desired configuration. The cam bodies can each include respective portions adapted to engage a cam rotation assist device 40. For example, when the cam body 20 rotates a preselected amount, the portion thereof engages the cam rotation assist device 40 so that at least a portion of the device is moved and thereby stores energy and/or a predetermined force therein. When the bow is shot, this energy and/or predetermined force urges and/or pushes the cam body to rotate faster, at least upon initiation of the bow being shot, and initial rotation of the cam during the shot cycle. This in turn can overcome inertia of the cam bodies, can improve nock travel and/or can produce a softer draw stop.

In the current embodiment of a dual cam bow, the upper and lower cam bodies or assemblies can include generally the same components, and can operate in a similar manner. Accordingly, only the upper cam assembly 20 and associated components will be described in significant detail herein, with the understanding that the lower cam assembly 30 can include the same components and can operate in a similar manner in this embodiment and other embodiments herein.

Although the current embodiment herein is described in connection with a dual cam bow, the cam assemblies 20, 30, bowstrings, cables and other features are suited for use with simpler pulley systems, for example, in single cam systems. The cam assembly, bowstrings, cables and other features also can be used in other dual cam, cam and a half, and single cam systems as well. Further, the embodiments herein are well suited for cam assemblies of single cam compound archery bows, dual cam bows, cam and a half bows, crossbows and other archery systems including a cam. 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 assembly, for use with an archery bow. 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 assembly, 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. The cam and/or module can be formed from rigid material, such as a metal, optionally aluminum, titanium, or magnesium, or a non-metal, optionally composites and/or polymers.

As used herein, an “axis of rotation” refers to an axis about which a cam can and/or does rotate, for example, an axis 5 as shown in FIG. 2. This axis can coincide with the center of an axle 50 if desired. Although not described in detail, the cam assemblies 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 assemblies also can include draw stops and other components common to cams as desired.

Turning now to the current embodiment of the archery bow 10, the cam body 20 can optionally include a first bowstring cam 21 and a second bowstring cam 22, each including respective bowstring tracks. The first and second bowstring cams can form the outer portions of the cam body 20. The cam parts 21, 22 can be mirror images of one another, with identical peripheral sizes and/or shapes. The cams can be generally perpendicular to the axis of rotation 5, and can be located in planes that are substantially parallel to the plane in which the bowstring is located when the bow is in its undrawn state, and/or in which the bowstring generally moves during its draw and/or release cycle. Of course, one of these bowstring cams can be removed or deleted from the construction as desired. Further, although only two bowstring tracks are shown, additional bowstring tracks may be added.

The bowstring cam parts 21, 22 can be in the form of individual cams that are joined together with one another, and optionally other elements such as a power cable cam 30, via fasteners such as screws, rivets, welds, and other fastening structures. Alternatively, the cam parts can be in the form of a monolithic, continuous single piece structure that includes the cam parts and the respective features thereof. The cam body 20 and its components 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.

The cam body 20 can be rotatably mounted on the limb 15 via an axle 50 that projects through an aperture defined by the cam body 20. In general, the cam body can be adapted to rotate about the axis of rotation 5. The axle 50 can be an integral part of the cam body, or can rotate with the cam body, or can be configured so that the cam body rotates about the axle. Optionally, the axle and/or limb can include suitable bearings to enhance rotation of the cam body 20. Suitable bearings include, but are not limited to, bushings, roller bearings, and ball bearings.

As shown in FIGS. 1 and 4, the cam body 20 also can include a power cable cam 60. This power cable cam 60 can be located between the first and second cams 21, 22, or adjacent a single cam if only one is included. The power cable cam 60 can be integrally formed and monolithic with one or more of the respective first bowstring cam 21 and second bowstring cam 22. Optionally, the power cable cam 60 can be fastened with fasteners as described above to the respective first bowstring cam part and second bowstring cam part.

As shown in FIGS. 4 and 8, the power cable cam 60 can define a power cable track 61, which can be of the same geometric cross section as the respective bowstring cable tracks. The power cable track 61 can include a power cable take up portion and a power cable let out portion. The power cable let out portion and take up portion can be contiguous with one another and can lie within the same power cable track as illustrated. One suitable cable track construction that accommodates different power cables is a single track power cable construction. The down cable 11 can be let out from the power cable let out portion when the archery bow 10 is drawn and the cam body 20 rotates about the axis 5 in the direction 13. Simultaneously and synchronously, the up cable can be taken up by the take up track portion the power cable track.

As mentioned above, the cam rotation assist device 40 can be configured to engage a portion of the cam body 20. For example, the cam body 20 can include a cam body projection 25 which extends laterally outward away from the cam body. As shown in FIGS. 1-4, this cam body projection 25 can be in the form of a draw stop. The draw stop 25 can be in the form of a cylindrical projection that is movably mounted in a draw stop slot 20 5S of the cam body 20. The draw stop 25 can be adjusted to provide a particular draw length and/or wall within the slot 25S. The draw stop can be secured in a fixed position relative to the slot 25S via one or more fasteners that projects through the least a portion of the draw stop in the slot and/or otherwise engaged cam body to secure the draw stop to the cam body 20. Optionally, the draw stop can include one or more elastomeric bumpers 25B, as shown in FIG. 4. These elastomeric bumpers can be in the form of O-rings, which circumferentially a portion of the draw stop that is configured to engage the limb 15 of the bow 10. With the elastomeric bumpers, the draw stop is prevented from marring, scratching, denting and/or otherwise damaging the portion of the limb and/or cam rotation assist device that engages. It will be understood that the elastomeric bumpers on the draw stop do not provide sufficient rebound energy, nor do they store sufficient energy therein, to effectively urge rotation of the cam body when the archery bow is shot.

As shown in FIG. 2, the draw stop travels along and arcuate path 25P as the cam body 20 is rotated in direction 13. As the draw stop 25 travels along the past 25P, it generally follows a circular path about the axis of rotation 5. In this construction, the draw stop 25 remains a fixed distance from that axis 5. Optionally, the path 25P can be noncircular and/or irregular depending on the placement of the cam projection and its ability to move relative to the cam body.

Although not shown, the cam projection used to engage the cam rotation assist device 40 can be some other type of cam body projection, other than a draw stop that projects laterally outward from the side surfaces of the cam body. As an example, an additional cam projection can be included on the cam body between the draw stop and the axis of rotation 5, with the projection being mounted closer to the axis than the draw stop. This cam body projection can also be movable within a slot (not shown) that projects radially away from the axis 5. The cam projection can be moved closer to or farther away from the axis of rotation to provide more or less rotational force and/or energy exerted thereupon by the cam rotation assist device.

Optionally, the cam projection 25 can be duplicated on opposite sides of the cam body 20. For example, first and second draw stops 25 can extend laterally outward from the cam body on opposite surfaces or sides of the cam body 20. In addition, the cam rotation assist 40 device can be duplicated so that corresponding cam rotation assist devices are positioned on opposite sides of the cam body to engage the respective cam projections on opposite sides of the cam body. In some cases, this can provide a balanced amount of force and energy that is applied to the cam body to begin its rotation after the archery bow is shot, and/or during the shot cycle.

The cam projection 25 can be configured to move in a direction so that it can engage the cam rotation assist device 40 along its path 25P. As shown in FIGS. 1-4, the cam assist rotation device 40 is in the form of a mini limb, which can include a cantilevered portion 41 that extends outward and terminates at a free end 42. The second end 43, of the cantilevered portion 41, can be fixedly secured to the limb 15 via a fastener 44. Optionally, the second end 43 of the mini limb 40 can be secured via an adhesive, a glue and the like, or it can be embedded in the tip of the limb 15 as desired. The particular length of the mini limb 40 can be selected depending on the desired amount of rotation it imparts upon the cam body. In some cases, the mini limb can be very short with its end located near the axis of rotation 5. In this construction, the mini limb can sometimes exert greater rotational forces on the cam body than in constructions where the mini limb is longer. The particular length can be varied depending on the application.

As illustrated in FIG. 2, the mini limb can include a slight curvature C. With this curvature, for example, optionally, a concave curvature away from the limb, the cantilevered portion 41 can be a distance farther and farther from the lower surface 15L of the limb 15 in progressing toward the free end 42. For example, the free end 42 can be a distance D2 away from the lower surface 15L of the limb 15. Moving toward the second end 43 the cantilevered portion 41 can be another distance D1 away from the lower surface 15L of the limb 15. The distance D2 can be greater than the distance D1, optionally by about 0.1 mm to about 20 mm or more, depending on the particular application. Of course, in other applications, the mini limb might not include a slight curvature, but instead can include an abrupt curvature so that the mini limb and in particular the free end begins to engage the draw stop earlier in the draw cycle of the bow. In yet other applications, the mini limb can simply be abruptly angled on a portion thereof so that the free end projects outward away from the lower surface 15L of the limb. These constructions can be varied depending on the application.

The mini limb also can include an upper surface 40U and a lower surface 40L. The upper surface 40U can be configured so that when the mini limb is engaged by the cam projection 25, that upper surface 40U engages the lower surface 15L of the limb 15. The lower surface 40L can be the surface that the cam projection 25 itself engages to begin to move and/or bend or flex the mini limb.

The mini limb can be constructed from metal, composites, polymers and or other materials. The mini limb also can be configured to engage the cam projection for optionally 0° to 360°, further optionally 0° to 180°, even further optionally 0° to 90°, yet further optionally 0° to 45°, even further optionally 0° to 10° yet even further optionally 0° to 5°, and even further optionally 0° to 2° of rotation of the cam body 20 and/or movement of the cam projection along the pathway 25P.

In operation, the archery bow 10 having the cam rotation assist device 40 typically begins in the bow's undrawn state, which is shown in FIGS. 1 and 2. When archer begins to exert a draw force DF on bowstring 70 as shown in FIG. 2, the cam body 20 begins to rotate in direction 13, about the axis of rotation 5, and in particular the axle 50. Likewise the draw stop and/or cam projection 25 begins to move along the path 25P. When the bow reaches the fully drawn state shown in FIGS. 3 and 4, the bowstring 70 is fully paid out. In this drawn state, and immediately before reaching it, the cam projection 25 engages the cantilevered portion 41, and in particular convex portion near the free end 42 of the mini limb 40. Because the mini limb is in a slightly curved and/or angled configuration, and is constructed from a generally resilient material or of a resilient structure, the mini limb bends or flexes or otherwise moves so that the free end moves toward the lower surface 15L of the limb 15.

The draw stop and/or cam projection 25 continues to bend or flex the mini limb until its upper surface 40U engages the lower surface 15L of the limb 15. During this engagement of the draw stop with the mini limb, the draw force DF exerted on the bowstring 70 is converted partially to a stored energy and/or a stored force in the bent, flexed or otherwise moved mini limb. Likewise, optionally when the mini limb is compressed and the free end 42 moves toward the limb 15, this action can be felt by the archer who experiences a softer draw stop. For example, the draw stop engages the mini limb it slowly decelerates until the mini limb is fully bent flexed or compressed, so that the archer does not experience the abrupt stopping of the draw stop 25 when it directly engages the limb 15.

The cam rotation assist device 40, in the form of the mini limb shown in FIGS. 3 and 4, stores rotational force and/or energy therein when the bow is fully drawn. When the bow is shot, the cam body 20 begins to rotate in direction 18, under significant forces also stored in the limb 15. It is believed that these forces exerted by the limb 15 on the cam body 20 are substantially linear, acting primarily on the axle 50 of the cam body to move the cam body in a linear path. Thus, it is believed that with conventional bows, the limbs do not assist much in rotating the cams, particularly upon initial release of the bowstring. With the current embodiments and in particular the cam assist device, the energy and forces stored therein exert a rotational force RF on the cam projection. As an example, as the mini limb releases the energy and forces therein, it urges the free end 42 away from the lower surface 15L of the limb. In so doing, the free end 42 also pushes and urges the draw stop along its circular path 25P, back toward the undrawn state. This translates to rotational force and rotational speed of the cam body 20 which thereby rotates more quickly due to the forces and energy exerted upon it by the mini limb. In turn, this can result in faster arrow speed, more even nock travel, and can improve the dynamic efficiency of the bow in general. At a certain point along its path 25P, the cam projection 25 disengages the mini limb, however by this point in rotation, the mini limb has already exerted the forces to get the cam body rotating more quickly. Draw stop 25 continues to move along its path 25P as the cam body returns to its initial position in the undrawn state of the archery bow 10.

A first alternative embodiment of the archery bow and in particular the cam rotation assist device is illustrated in FIGS. 5 and 6 and generally designated 110. This embodiment is similar to the embodiment described above in structure, function and operation with several exceptions. For example, the archery bow 110 includes a cam body 120. The cam body 120 includes a cam projection 125, optionally in the form of a draw stop. The cam rotation assist device 140 in this configuration however is in the form of a mini limb that is secured at first and second ends 143A and 143B to the lower surface 115L of the limb 115. The securement can be via fasteners, glue, adhesives or other structures. The central portion 141 of the mini limb in this embodiment however is in the form of a hump. The hump is disposed in the path 125P of the draw stop 125. As illustrated in FIG. 6, when the bow is drawn to a drawn state, the cam projection 125 engages the central portion 141 of the mini limb. Due to the flexible and resilient nature of the mini limb, the central portion and/or hump bends and/or flexes or otherwise moves toward the lower surface 115L of the limb 115. In so doing, the mini limb stores energy and forces therein which, as described in connection with the embodiment above, assist in initially rotating the cam body 120 when the bow is initially shot.

A second alternative embodiment of the archery bow and in particular the cam rotation assist device is illustrated in FIGS. 7-9 and generally designated 210. This embodiment is similar to the embodiment described above in structure, function and operation with several exceptions. For example, the archery bow 210 includes a cam body 220 rotatably mounted to a limb 215 via an axle 250 in this manner, the cam body to 23 to rotate about axis of rotation 205 when the bow is drawn from an undrawn state to a drawn state. In this construction, the cam body to 20 can also include one or more draw stops 225 as shown in FIG. 9. These draw stops, however, do not form or assist in the function of the cam rotation assist device 240. In this construction, the cam assist rotation device 240 is in the form of a coil spring that is wrapped at least partially around the axle 250. Optionally, the coil spring has a central axis that corresponds to the axis of rotation 205 of the cam body.

As shown in FIGS. 7 and 9, the archery bow to 10 is in an undrawn state. The coil spring 240 can include first and second portions 241 and 242. These first and second portions can be in the form of tangs that are integrally formed with the coil spring. The coil spring itself can be constructed from coiled metal, composites and/or polymers. The tangs 241 and 242 can be configured to enter fit at least partially within respective apertures or hole 221 defined by the cam body, and hole 212 defined by the limb 215. The particular holes need not be in the specific components, but otherwise can be defined elsewhere or in other components, as long as the ends of the coil spring are connected to the cam body in some other structure so that is the cam body is rotated the coil spring at some point is coiled and/or uncoiled to thereby store forces and/or energy therewithin.

More particularly, as shown in FIGS. 7 and 8, as the archery bow transitions from an undrawn state in FIG. 7, the first end 241 of the coil spring, trapped in the hole 221 of the cam body, travels along the path 225. The second end 242 remains trapped and an movable within the second hole to 12 of the limb 215. Thus, as the cam body rotates in direction 213 to the fully drawn state of the bow shown in FIG. 8, the coil spring is further coiled or uncoiled, and thereby stores energy and rotational force therein. When the bow is shot, initially the coil spring 240 exerts the rotational force RF to accelerate rotation of the cam body 220 about the axis of rotation 205. In turn, this provides benefits similar to those of the embodiments above.

As shown in FIG. 9, the coil spring 240 optionally can be duplicated on opposite sides of the cam body 220 to provide a balanced rotational force to the cam body. The components of the second coil spring 240′ can be identical to but reversed from that of the coil spring 240.

A third alternative embodiment of the archery bow and in particular the cam rotation assist device is illustrated in FIGS. 10-12 and generally designated 310. This embodiment is similar to the embodiment described above in structure, function and operation with several exceptions. For example, the archery bow 310 includes a cam body 320. The cam body 320 is rotatably mounted to the limb 315. Optionally, the cam body 320 can also include a draw stop 325. This draw stop 325 however is not part of and does not function with the cam rotation assist device 340. Instead, the rotation assist device 340 includes first 341 and second 342 magnetic elements. The first magnetic element 341 can include one or more programmable or “coded magnets” such as exemplary 341A, 341B. Of course fewer or more coded magnets can be used, depending on the application. Indeed, in some applications, 10 to 20 to 50 or more coded magnets can be used in an array to selectively rotate the cam body if desired.

When used herein, a programmable magnet or a coded magnet includes any magnetic assembly including a plurality of discreet individual magnets, which are referred to as maxels. The maxels cooperatively produce a magnetic field profile. The overall magnetic field of the coded magnet, and thus the magnetic force, or predetermined force, which it exerts on other objects or structures, depends on an arrangement of the constituent magnetic elements. Thus, by consistently and systematically positioning maxels within a body of a coded magnet, a magnetic force curve having a specific magnetically attractive and/or magnetically repulsive force when in certain orientations can be generated. A coded magnet can include a maxel pattern that varies in at least two dimensions. Thus, rotational alignment of the coded magnet relative to another magnetic element, for example, a ferrous material or a correlated magnet as described below, may force associated objects such as a cam body to rotate and/or otherwise move under the predetermined force generated by the coded magnet and its associated magnetic field. Generally, the coded magnets herein can be formed from a plurality of permanent maxels and/or a plurality of electromagnetic maxels. Other configurations of certain magnets are disclosed in U.S. Pat. No. 8,947,185 to Fullerton, which is hereby incorporated by reference in its entirety.

The second magnetic element 342 can be in the form of a ferrous material pods 342A, 342B, that are void of any magnets, but that is still effected by a magnetic field and/or magnetic force exerted upon it by magnets such as 341A and 341B as disclosed herein. This magnetic element can be included in a cam body region 343, which itself can be constructed from aluminum or other non-ferrous metals or composites, and which can be located adjacent the optional draw stop 325 when included. Alternatively, the second magnetic element 342 can include its own coded magnet depending on the application.

The coded magnets 341A and 341B can be configured to lie along a pathway 342P of the magnetic elements 342A and 342B, which pathway can be circular or irregular, depending on the application. The magnets 341A and 342B can be secured to the limb 315 via first and second housings 345A and 345B, which are secured to the lower and/or upper surfaces of the limb 315. These housings can be secured with fasteners, adhesives and the like to the limb.

When the bow is in the undrawn state, shown in FIG. 10, the magnetic elements 342A and 342B are distal from the coded magnets 341A and 341B. Thus the coded magnets exert little to no magnetic force on them. When the bow is drawn to the drawn state shown in FIGS. 11 and 12, the magnetic elements are in proximity to and within the magnetic field of the coded magnets. The coded magnets therefore exert a repulsive magnetic force on the magnetic elements while the magnetic elements are adjacent to the coded magnets as shown in FIG. 12. This magnetic force is however, overcome by the draw force exerted by the archer on the bow.

When the bow is shot however, the coded magnets operate to exert the magnetic force MF on the magnetic elements, repelling them substantially, and in turn, urging the cam body to rotate in direction 318 about the axis of rotation 305 as the cam starts to rotate in the initial stages of the shot cycle. This assists the cam body in starting to rotate quickly toward the orientation of the cam body in the undrawn state. In turn, this provides benefits similar to those of the embodiments above.

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).

The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and 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, and any combination of X, Y and Z, for example, X, Y, Z; X, Y; X, Z; and Y, Z.

Claims

1. An archery bow comprising:

at least one limb;

a bowstring;

a bowstring cam defining a bowstring groove, the bowstring groove adapted to receive the bowstring, the bowstring cam adapted for rotation relative to the at least one limb;

a power cable;

a power cable cam joined with the bowstring cam in a fixed position, the power cable cam defining at least one of a power cable take up groove and a power cable let out groove;

an axle to which at least one of the bowstring cam and the power cable cam is joined;

a cam rotation assist device joined with the at least one limb; and

a cam projection joined with at least one of the bowstring cam and the power cable cam, the cam projection distal from the axle, the cam projection adapted to travel in a non-linear pathway as the bow is draw to a drawn mode, the cam projection adapted to engage the cam rotation assist device when the bowstring cam has rotated a preselected amount, so that the cam rotation assist device stores energy, so that the cam rotation assist device can urge the cam projection away from the limb when the bow is shot.

2. The archery bow of claim 1 wherein the cam rotation assist device is a mini limb joined with the at least one limb.

3. The archery bow of claim 2 wherein the cam projection is a draw stop, the draw stop including an elastomeric bumper.

4. The archery bow of claim 2,

wherein the draw stop compresses at least a portion of the mini limb upon drawing of the bow,

wherein the mini limb moves toward the limb when engaged by the drawstop.

5. The archery bow of claim 1,

wherein the cam rotation assist device includes a cantilevered portion with a fixed end joined with the limb, and a free end distal from the fixed end,

wherein the free end engages the cam projection as the cam projection moves along the pathway as the bow is drawn.

6. The archery bow of claim 5,

wherein the cam projection urges the free end toward the limb as the bow is drawn,

wherein the cantilevered portion stores energy therein due to urging of the free end toward the limb.

7. The archery bow of claim 6 wherein the cantilevered portion exerts a force on the cam projection, thereby urging the bowstring cam to rotate when the archery bow is shot to return the bow to an undrawn state.

8. The archery bow of claim 1 wherein the cam rotation assist device includes a coil spring engaging at least one of the bowstring cam and the power cable cam.

9. The archery bow of claim 8 wherein the coil spring is coiled about the axle.

10. The archery bow of claim 1,

wherein the cam rotation assist device includes a first programmable magnet joined with at least one of the bowstring cam and the power cable cam, and a second programmable magnet joined with the limb,

wherein the first and second programmable magnets at least one of attract and repel one another to urge rotation of the at least one of the bowstring cam and the programmable cam upon initiation of a shot cycle of the archery bow.

11. An archery bow comprising:

a limb;

a cam body rotatably joined with the limb;

a bowstring engaging the cam body;

a cam rotation assist device adapted to engage a portion of the cam body so as to urge rotation of the cam body independent of the limb;

wherein the cam body rotates faster upon initiation of a shot cycle of the archery bow due to the urging by the cam rotation assist device than the cam body otherwise would rotate upon initiation of the shot cycle if the cam rotation assist device was absent.

12. The archery bow of claim 11 wherein the cam body includes a cam projection extending laterally from the cam body and movable along a circular path.

13. The archery bow of claim 12,

wherein the cam rotation assist device is placed along the circular path, so that as the cam body rotates in a first direction, the cam projection compresses the cam rotation assist device so that the cam rotation in the first direction assist device stores energy therein,

wherein the stored energy urges rotation of the cam body in an opposite direction when the bow is shot and returns to an undrawn mode.

14. The archery bow of claim 11,

wherein the cam rotation assist device is a mini limb joined with the limb,

wherein the mini limb bends when the cam body rotates.

15. The archery bow of claim 11,

wherein the cam rotation assist device is a coil spring joined with the cam body,

wherein the coil string at least one of coils and uncoils upon rotation of the cam body.

16. The archery bow of claim 11,

wherein the cam rotation assist device includes a first programmable magnet joined with the cam body and a second programmable magnet selectively located adjacent a path of rotation of the first programmable magnet,

wherein the first and second programmable magnetic is adapted to at least one of attract and repel one another to thereby urge rotation of the cam body.

17. The archery bow of claim 11,

wherein the portion of the cam body is a draw stop that projects laterally from the cam body,

wherein the draw stop includes an elastomeric bumper surrounding at least a portion thereof to prevent marring of the cam rotation assist device which the draw stop engages.

18. An archery bow comprising:

a limb;

a cam body rotatably joined with the limb;

a bowstring engaging the cam body;

a mini limb joined with the limb, the mini limb disposed in a pathway of a portion of the cam body, the mini limb adapted to flex upon engagement of the mini limb by the portion of the cam body, with the mini limb storing a force within upon flexing, the mini limb exerting the force on the portion of the cam body when the bowstring moves from a drawn state to an undrawn state during a shot cycle of the archery bow;

whereby the cam body rotates faster due to the urging by the mini limb than the cam body otherwise would rotate if the mini limb was absent.

19. The archery bow of claim 18,

wherein the portion of the cam body includes a draw stop that projects laterally from the cam body,

wherein the draw stop engages the mini limb as the draw stops moves along a circular pathway about an axis of rotation of the cam body.

20. The archery bow of claim 18,

wherein the mini limb includes a fixed end joined with the limb and a free end that is distal from the fixed and spaced a distance from the limb,

wherein the mini limb bends upon engagement thereof by the portion of the cam body to reduce the distance from the limb.