COMPOUND BOW

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2013-0100228, filed on Aug. 23, 2013 and No. 10-2013-0164958, filed on Dec. 27, 2013 in the Korean Intellectual Property Office, the disclosures of which are incorporated in their entireties herein by reference and to which priority is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compound bow, and more particularly, to a compound bow which can prevent distortion of the bow and improve accuracy of an arrow when a bowstring is pulled.

2. Description of the Related Art

Typically, compound bows are configured so that a bowstring may be easily pulled without using a large force and arrow shooting power is increased during shooting, by using an effect of a cam or wheel, to thus result in a fast speed of an arrow and have very strong power, and are widely used mainly for hunting.

As shown in FIGS. 1 to 3, a conventional compound bow is configured to have upper limbs 20 that are coupled to the upper portion of a handle 10 at the center of which a grip portion is formed, and lower limbs 26 coupled to the lower portion of the handle 10. A cut-out portion 21 is formed between the upper limbs 20 whose edges 22 are spaced apart from each other, and a cut-out portion 27 is formed between the lower limbs 26 whose edges 28 are spaced apart from each other. Rotating shafts 70 are horizontally formed through the edges 22 of the upper limbs 20 and the cut-out portion 21, and through the edges 28 of the lower limbs 26 and the cut-out portion 27, respectively. Upper and lower pulleys 30 and 36 are rotatably combined with the respective rotating shafts 70.

A bowstring 50 is wound along a guide groove 31 or 37 of each pulley 30 or 36, and the respective ends of the bowstring 50 are combined with each pulley 30 or 36. In addition, a cam 32 or 38 rotating with the pulley 30 or 36 is coupled in each pulley 30 or 36. As the bowstring 50 is pulled, cam cables 40 and 46 are formed so as to be wound on the cams 32 and 38, respectively. One end of each cam cable 40 or 46 is coupled to a pulley 30 or 36 to which each cam 32 or 38 is coupled, and the other end of each cam cable 40 or 46 is coupled to each rotating shaft 70 at both sides of the cut-out portion 21 or 27 of each of the opposing limbs 20 and 26 in the form of Y-shaped buss cables 40a and 46a.

Further, a cable guard 60 is laterally mounted at one side of a center portion of a handle 10, in which the cable guard 60 pushes the cam cables 40 and 46 to one side of the bowstring 50 so that an arrow is not prevented from being shot during shooting. In addition, a slide 66 is movably mounted on the cable guard 60 in which the cam cables 40 and 46 are inserted into the slide 66.

When the bowstring 50 is pulled in the prior art compound bow that is configured as described above, the lower and upper pulleys 30 and 36 are rotated and thus the cams 32 and 38 coupled to the lower and upper pulleys 30 and 36 are rotated, to thereby wind and pull the cam cables 40 and 46. When the bowstring 50 is released in a let-off state, an arrow obtains a strong driving force by a strong elastic force of the bow which returns to an original position instantaneously.

However, in order to prevent the cam cables 40 and 46 which are located in front of the bowstring 50 from interfering with the shooting of an arrow in the compound bow, the cam cables 40 and 46 are compulsively supported in one direction by the cable guard 60 and the cams 32 and 38 are combined on an identical one side surface of the respective pulleys 30 and 36. Therefore, the pulleys 30 and 36 around which the bowstring 50 is wound are not located at the center of each of the limbs 20 and 26 as shown in FIG. 2. Accordingly, when the bowstring 50 is pulled, the bow limbs 20 and 26 and pulleys 30 and 36 are twisted as shown in FIG. 3. As a result, the inherent strength of the bow is not exhibited and the accuracy of the arrows is also dropped. Thus, although the buss cables 40a and 46a are adjusted with a tool to thereby control the bow limbs to be inclined to the left and right, it is very difficult to adjust the buss cables 40a and 46a for the left and right balance of the bow limbs 20 and 26 except for a person who has a skill of adjustment of the buss cables 40a and 46a, due to difference of the forces applied on the limbs when compared with an initial state of the limbs when the bowstring 50 is pulled.

SUMMARY OF THE INVENTION

To solve the above conventional problems or defects, it is an object of the present invention to provide a compound bow to prevent twisting of the bow, to exhibit inherent strength of the bow, and to improve accuracy of an arrow.

To accomplish the above and other objects of the present invention, according to an aspect of the present invention, there is provided a compound bow comprising: a bow main body including a handle at a central portion of which a grip portion is formed and a pair of limbs that are respectively coupled to both ends of the handle; upper and lower pulley assemblies each including a pulley that is rotatably coupled to a rotating shaft formed on the rear end of each limb, and a cam that is coupled to one side of the pulley and rotating with the pulley; a bowstring whose either end is wound and coupled to the pulley of each of the upper and lower pulley assemblies; and two cam cables that are wound around the cam of each of the upper and lower pulley assemblies as the bowstring is pulled, in which one end of each of the two cam cables is coupled to one of the upper and lower pulley assemblies, and the other end thereof is coupled to the other of the upper and lower pulley assemblies or the rotating shaft of the other of the upper and lower pulley assemblies; wherein at least one of the upper and lower pulley assemblies further comprises: a rotating wheel that is coupled with the rotating shaft of the pulley on the other side surface opposing to one side surface of the pulley to which the cam is coupled, in which one of the two cam cables is coupled to the other side surface of the pulley, wound on the rotating wheel, and extended toward the other of the upper and lower pulley assemblies; and a cam cable guide member one end of which is rotatably coupled to the rotating shaft of the pulley separately from the pulley, at one side of the rotating wheel, in which the cam cable guide member is extended by a predetermined length along one of the cam cables extended toward the other of the upper and lower pulley assemblies from the rotating wheel, and at the other end of which a support member for supporting one of the cam cables is formed in order to make a portion of one of the cam cables extended from the rotating wheel guided in parallel with the pulley.

Preferably but not necessarily, the rotating wheel is rotatably coupled to the rotating shaft separately from the pulley.

Preferably but not necessarily, the support member of the cam cable guide member comprises a guide pulley and a support pulley that are respectively rotatably coupled to two shaft members respectively located at both sides of the cam cable, in which the cam cable is supported between the guide pulley and the support pulley.

Preferably but not necessarily, a guide groove for guiding the cam cable is formed on an outer circumferential surface of the guide pulley.

Preferably but not necessarily, the support pulley is formed at the front of the guide pulley, and is located at a longer distance from the rotating shaft of the cam cable guide member than the guide pulley.

Preferably but not necessarily, the support pulley is formed to have an outer diameter of an outer circumferential surface of the support pulley that guides the cam cable in contact with the cam cable becomes smaller inwards, and thereby guide the cam cable to a cable guard that is coupled to the handle of the bow main body and pushes the cam cable in one direction.

Preferably but not necessarily, the compound bow further comprises a support bar one end of which is rotatably coupled to the rotating shaft separately from the pulley at the other side surface of the pulley to which the cam cable guide member is coupled, so as to oppose the cam cable guide member, and at the other end of which two support protrusions are formed for supporting each of the guide pulley and the pulley support of the cam cable guide member.

Preferably but not necessarily, two coupling portions to which the rotating shaft is coupled are formed at one end of the cam cable guide member, in which the two coupling portions are coupled to the rotating shaft at both sides of one of two branches adjacent to the rotating wheel of the two branches that form a rear portion of the limbs, and the cam cable guide member is made in an arch-shaped form.

Advantageous Effects

As described above, the present invention provides a compound bow to prevent twisting of the bow during use, to exhibit inherent strength of the bow, and to improve synchronizing to thus improve accuracy of an arrow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional compound bow.

FIG. 2 is a rear view of the compound bow of FIG. 1.

FIG. 3 is a perspective view showing a twisted state of a pulley assembly coupled to a limb of FIG. 1.

FIG. 4 is a side view showing a compound bow according to a first embodiment of the present invention before a bowstring is pulled.

FIG. 5 is a detailed view of a pulley assembly that is coupled to one of limbs in FIG. 4.

FIG. 6 is a side view showing a compound bow according to the first embodiment of the present invention after a bowstring has been pulled.

FIG. 7 is a detailed view of a pulley assembly that is coupled to one of limbs in FIG. 6.

FIG. 8 is a side view of the pulley assembly of FIG. 7 seen from the front side of the compound bow.

FIG. 9 is a side view showing a compound bow according to a second embodiment of the present invention before a bowstring is pulled.

FIG. 10 is a detailed view of a pulley assembly that is coupled to one of limbs in FIG. 9.

FIG. 11 is a side view showing a compound bow according to the second embodiment of the present invention after a bowstring has been pulled.

FIG. 12 is a detailed view of a pulley assembly in FIG. 11.

FIG. 13 is a side view of the pulley assembly of FIG. 12 seen from the rear side of the compound bow.

DETAILED DESCRIPTION OF THE INVENTION

The above and/or other objects and/or advantages of the present invention will become more apparent by the following description of embodiments of the present invention.

Hereinbelow, a compound bow according to a first embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 4 is a side view showing a compound bow according to a first embodiment of the present invention before a bowstring is pulled. FIG. 5 is a detailed view of a pulley assembly that is coupled to one of limbs in FIG. 4. FIG. 6 is a side view showing a compound bow according to the first embodiment of the present invention after a bowstring has been pulled. FIG. 7 is a detailed view of a pulley assembly that is coupled to one of limbs in FIG. 6. FIG. 8 is a front view of the pulley assembly of FIG. 7 seen from the front side of the compound bow.

Referring to FIGS. 4 to 8, a compound bow according to a first embodiment of the present invention includes: a bow main body 100 including a handle 102 at a central portion of which a grip portion is formed and a pair of limbs 103 that are respectively coupled to both ends of the handle 102; upper and lower pulley assemblies each including a pulley 110 that is rotatably coupled to a rotating shaft 101 formed on the rear end of each limb 103, and a cam 200 that is coupled to one side of the pulley 110 and rotating with the pulley 110; a bowstring 140 whose either end is wound and coupled to the pulley 110 of each of the upper and lower pulley assemblies; and two cam cables 150 that are wound around the cam 200 of each of the upper and lower pulley assemblies as the bowstring 140 is pulled, in which one end of each of the two cam cables 150 is coupled to one of the upper and lower pulley assemblies, and the other end thereof is coupled to the other of the upper and lower pulley assemblies or the rotating shaft 100 of the other of the upper and lower pulley assemblies.

At least one of the upper and lower pulley assemblies further includes: a rotating wheel 120 that is rotatably coupled with the rotating shaft 101 of the pulley 110 on the other side surface opposing to one side surface of the pulley 110 to which the cam 200 is coupled, in which one of the two cam cables 150 is coupled to the other side surface of the pulley 110, wound on the rotating wheel 120, and extended toward the other of the upper and lower pulley assemblies; and a cam cable guide member 300 one end of which is rotatably coupled to the rotating shaft 120 of the pulley 110 separately from the pulley 110, at one side of the rotating wheel 120, in which the cam cable guide member 300 is extended by a predetermined length along one of the cam cables 150 extended toward the other of the upper and lower pulley assemblies from the rotating wheel 120, and at the other end of which a support member 310 for supporting one of the cam cables 150 is formed in order to make a portion of one of the cam cables 150 extended from the rotating wheel 120 guided in parallel with the pulley 110.

As shown in FIGS. 4 to 8, the compound bow according to a first embodiment of the present invention employs a dual cam system the respective components of which will be described below in more detail. First, the bow main body 100 includes a handle 102 at a central portion of which a grip portion is formed so as to be gripped by a user, and a pair of limbs 103 each having two branches. A rotating shaft 101 is formed at the rear end of each limb 103, in which a pulley assembly is rotatably coupled on the rotating shaft 101 between the two branches of each limb 103. A cable guard 105 that pushes the cam cables 150 to one side of the bowstring 140 is coupled at the central portion of the handle 102, in order to prevent an arrow from being interrupted during shooting.

Then, each of the upper and lower pulley assemblies is rotatably coupled to the rotating shaft 101 at the rear end of each limb 103, and includes: a pulley 110 that is rotatably coupled to the rotating shaft 101 formed at the rear end of each limb 103; and a cam 200 coupled to one side of the pulley 110 and rotating with the pulley 110.

Each pulley 110 is formed of an oval-like plate-shaped member, and has an eccentric through-hole that is formed at the center of the pulley 110 and through which the rotating shaft 101 is coupled. Further, a guide groove that is depressed down to a predetermined depth is formed on the outer circumferential surface of each pulley 110 so that the bowstring 140 may be wound on the outer circumferential surface of each pulley 110. A fixing protrusion 111 for fixing one end of the bowstring 140 wound on the guide groove is formed at one side of each pulley 110. In addition, fixing protrusions 112 and 113 are formed in each pulley 110 in which the cam cables 150 are fixed to the fixing protrusions 112 and 113.

The cam 200 is coupled to one side of each pulley 110 and is rotated with rotation of the pulley 110 to thus make the cam cables 150 wound on the cam 200, and includes: a cam cable winding portion 210 fabricated in an arc-shaped form and on which one of the cam cables 150 is wound; and a cam module 220 that has a pivot axis 221 at a position spaced by a predetermined distance from the rotating shaft 101 of the pulley 110 to which the cam 200 is coupled, and that is rotatably coupled to the pivot axis 221 by a predetermined angle from the cam cable winding portion 210, in which a cam cable winding groove is formed on the outer circumferential surface of the cam module 220, and the cam cable 150 is wound around the cam cable winding portion 210 and then sequentially wound on the outer circumferential surface of the cam module 220 when the bowstring 140 is pulled.

The cam cable winding portion 210 is arc-shaped so that the cam cable 150 is wound on the cam cable winding portion 210, when the bowstring 140 is pulled, in which one end of the cam cable 150 is coupled to the fixing protrusion 112 that is located in the vicinity of the cam cable winding portion 210. In addition, a cam cable winding groove is formed on the outer circumferential surface of the cam cable winding portion 210 so that the cam cable 150 is wound on the outer circumferential surface of the cam cable winding portion 210.

The cam module 220 has the pivot axis 221 at a position spaced by a predetermined distance from the rotating shaft 101 of the pulley 110 to which the cam 200 is coupled, and is rotatably coupled to the pivot axis 221 by a predetermined angle from the cam cable winding portion 210, and is configured to have a gentle slope portion 222 formed of a gentle arc-shaped curve and a steep slope portion 223 that is extended from the gentle slope portion 222 to be close to the rotating shaft 101, to thus form a steep slope. Further, the cam cable winding grooves on which the cam cable 150 is wound are formed on the outer circumferential surfaces of the gentle slope portion 222 and the steep slope portion 223. Accordingly, the cam module 220 is rotated along with the pulley 110 when the bowstring 140 is pulled, and thus the cam cable 150 is sequentially wound on the gentle slope portion 222 and the steep slope portion 223 of the cam module 220 adjacent to the cam cable winding portion 210. Thus, the cam module 220 is rotated by a predetermined angle around the pivot axis 221 and is fixed to the pulley 110 by using a bolt at a position where the cam module 220 has been rotated. Rotation of the module cam 220 is to adjust the length of the pull at a let-off state.

The bowstring 140 is wound in the guide groove of the pulley 110 of each pulley assembly and thus both ends of the bowstring 140 are coupled to the fixing protrusions 111 formed on the respective pulleys 110.

The cam cables 150 are formed between a pair of the limbs 103 of the bow main body 100 and are wound on the cams 200 formed in the respective pulleys 110, as the bowstring 140 is pulled. One end of each of the cam cables 150 is coupled to the fixing protrusion 113 formed on the pulley 110 of one of the pulley assemblies, and then is wound around the rotating wheel 120 that is rotatably coupled to the rotating shaft 101, and the other end of each of the cam cables 150 is extended toward the other of the pulley assemblies to then be fixed to the fixing protrusion 112 of the pulley 110 of the other of the pulley assemblies. Therefore, as the bowstring 140 is pulled, the cam cables 150 are wound on the cam 200 that is coupled to the other pulley 110 of the pulley assemblies.

The rotating wheel 120 is configured to have a through-hole at the center of the rotating wheel 120 in which the rotating shaft 101 of the pulley 110 is coupled into the through-hole, and to be coupled to the rotating shaft 101 of the pulley 110 at the other side surface of the pulley 110, that is, at the other side surface opposing one side surface of the pulley 110 to which the cam 200 is coupled, and to be rotatably coupled to the rotating shaft 101 of the pulley 110 separately from the pulley 110. Further, the cam cable winding groove into which the cam cable is wound is formed on the outer circumferential surface of the circular rotating wheel 120. Thus, the cam cable 150 is wound on the rotating wheel 120 and then one end of the cam cable 150 is coupled to the fixing protrusion 113 formed on the pulley 110 in the vicinity of the rotating wheel 120. The cam cable 150 is wound on the cam 200 of the other pulley 110 by the pulling of the bowstring 140, and accordingly a portion of the cam cable 150 wound on the rotating wheel 120 is released from the rotating wheel 120. Here, since the rotating wheel 120 is rotatably coupled to the rotating shaft 101 separately from the pulley 110, friction between the cam cable 150 and the rotating wheel 120 is reduced to thus reduce the pulling force of the bowstring 140.

The cam cable guide member 300 plays a role of making a portion of the cam cable 150 extended from the rotating wheel 120 guided in parallel with the pulley 110, and is rotatably coupled to the rotating shaft 101 of the pulley 110 at one side surface of the rotating wheel 120 to thus be extended by a predetermined length along the extending direction of the cam cable 150. To this end, a through-hole is formed at one end of the cam cable guide member 300 in which the rotating shaft 101 of the pulley 110 is coupled into the through-hole, and a support member 310 for supporting the cam cable 150 is formed at the other end of the cam cable guide member 300, in which a portion of the cam cable 150 extended from the rotating wheel 120 is guided in parallel with the pulley 110.

The support member 310 of the cam cable guide member 300 includes a guide pulley 320 and a support pulley 330 that are respectively rotatably coupled to two shaft members 302 and 303 respectively located at both sides of the cam cable 150, in which the cam cable 150 is supported between the guide pulley 320 and the support pulley 330. The guide pulley 320 plays a role of guiding the cam cable 150 to be guided in parallel with the pulley 110, and is rotatably coupled to the shaft member 302 that is protruded toward the pulley 110 at the other end of the cam cable guide member 300, in which a guide groove 311 for guiding the cam cable 150 is formed on the outer circumferential surface of the guide pulley 320. The guide pulley 320 is formed closer to the rotating shaft 101 than the support pulley 330.

The support pulley 330 plays a role of guiding the cam cable 150 to be guided in parallel with the pulley 110, together with the guide pulley 320, and simultaneously guiding the cam cable 150 to be guided toward the cable guard 105 via the support pulley 330. The support pulley 330 is formed farther from the rotating shaft 101 at the front of the guide pulley 320 than the guide pulley 320, and is rotatably coupled to the shaft member 303 that is protruded toward the pulley 110 at the other end of the cam cable guide member 300. The shaft member 303 to which the support pulley 330 is coupled is longer than the shaft member 302 to which the guide pulley 320 is coupled. Thus, the support pulley 330 is also larger than the guide pulley 320 in width. As shown in FIG. 8, the cam cable 150 is vertically from the rotating wheel 120 to the guide pulley 320, that is, in parallel with the pulley 110, and then is bent toward the other side surface of the pulley 110 over the guide pulley 320 in order to be inserted into the cable guard 105. As described above, the cam cable 150 is bent toward the cable guard 105 over the guide pulley 320.

Further, as shown in FIG. 8, the support pulley 330 is configured to have an outer circumferential surface that guides the cam cable 150 in contact with the cam cable 150 along the travelling direction of the cam cable 150 in which the outer diameter of the outer circumferential surface becomes smaller inwards (that is, toward the pulley 110). As shown in FIGS. 4 and 5, the cam cables 150 are formed askew from the point of view of the bow, and as shown in FIG. 8, the cam cable 150 is bent toward the other side surface of the pulley 110 over the guide pulley 320 in order to be inserted into the cable guard 105. As described above, since the support pulley 330 is configured so that the outer diameter of the outer circumferential surface of the support pulley 330 that contacts the cam cable 150 becomes smaller inwards, the support pulley 330 supports the cam cable 150 from the incoming portion of the cam cable 150 to the outgoing portion of the cam cable 150 in the support pulley 330, and thus when the bowstring 140 is pulled, the cam cable 150 is guided toward the cable guard 105 more reliably.

Since the cam cable guide member 300 is configured to have the above-described structure, the cam cable 150 does not come into contact with the pulley 110 and the cam cable 150 is also guided in parallel with the pulley 110 when the bowstring 140 is pulled. As a result, direction of a force applied to each of the cam cables 150 is parallel to the bowstring 140, thereby preventing distortion of the bow limbs 103.

Further, since the guide pulley 320 and the support pulley 330 that guide the cam cable 150 are rotatably coupled to the shaft members 302 and 303, respectively, the friction of the cam cable 150 in contact with the guide pulley 320 and the support pulley 330 may be minimized to thus reduce a force that is needed to pull the bowstring 140.

Further, as shown in FIG. 8, a support bar member 400 is formed at the other side of the pulley 110 opposing one side of the pulley 110 to which the cam cable guide member 300 is coupled, so as to oppose the cam cable guide member 300. One end of the support bar member 400 is rotatably coupled to the rotating shaft 101 separately from the pulley 110, and is extended to have the same length as the cam cable guide member 300. Two support protrusions 402 and 403 that are protruded toward the support member 310 to support the guide pulley 320 and the support pulley 330 of the support member 310 are formed at the other end of the support bar member 400.

Thus, since the support bar member 400 opposite to the cam cable guide member 300 is coupled to the rotating shaft 101 at the other side of the pulley 110 to which the cam cable guide member 300 is coupled, the pulley 110 that is rotated as the bowstring 140 is pulled may be located at the center of the limbs 103, thereby preventing distortion of the limbs 103. Further, as shown in FIG. 8, the cam cable 150 is bent toward the cable guard 105, and thus the guide pulley 320 and the support pulley 330 that guide the cam cable 150 become tense by a force applied inwards as the bowstring 140 is pulled. Accordingly, since the support protrusions 402 and 403 of the support bar member 400 are configured to support the guide pulley 320 and the support pulley 330 at the other side of the guide pulley 320 and the support pulley 330, it is possible to promote the structural stability.

The operation of the compound bow according to the first embodiment of this invention will be described below.

As shown in FIGS. 4 and 5, before the bowstring 140 is pulled, one end of the cam cable 150 is coupled to the fixing protrusion 113 of one pulley 110, and is wound around the rotating wheel 120, and the other end of the cam cable 150 is coupled to the fixing protrusion 112 of the other pulley 110 over the guide pulley 320 and the support pulley 330 of the cam cable guide member 300. When the bowstring 140 is then pulled, the pulley 110 is rotated and thus the cam cable 150 wound around the rotating wheel 120 is released from the rotating wheel 120 and then wound on the cam 200 coupled to the opposing pulley 110. In addition, when the cam cable 150 is wound on the steep slope portion 223 of the cam module 220 coupled to the opposing pulley 110, the compound bow becomes a let-off state at which an arrow may be shot as shown in FIGS. 6 and 7.

Since the pulley 110 is located between the cam 200 and the rotating wheel 120 in the compound bow according to the first embodiment of the present invention, and thus the pulley 110 is located at the center of the limbs 103, the conventional Y-shaped buss cables 40a and 46a shown in FIG. 1 are not required, and accordingly adjustment of the buss cables 40a and 46a for preventing the bow limbs 103 from tilting from side to side is also unnecessary. In addition, the cam cable 150 is pulled from the cam 200 and the rotating wheel 120 that are located on both sides of the pulley 110 and thus balancing of the limbs 103 is improved, to thereby provide an advantage capable of exerting the strength of the original bow.

Further, when the cam cable 150 is released from the rotating wheel 120 and is traveled to the cam 200 coupled to the pulley 110 of the opposing pulley assembly, as shown in FIG. 8, the cam cable 150 is guided by the guide pulley 320 and the support pulley 330 of the cam cable guide member 300 coupled to the rotating shaft 101 at one side surface of the rotating wheel 120, and the cam cable 150 is guided in parallel with the pulley 110 as the bowstring 140 is pulled, without contact with the pulley 110 due to the guide pulley 320 and the support pulley 330. As a result, direction of the force being applied to the cam cable 150 is parallel to the bowstring 140, to thereby enhance the left and right balancing of the limbs, and improve synchronizing where both cams 200 become a let-off state simultaneously, and to thus also provide an effect of improving accuracy of an arrow.

Further, a portion of the cam cable 150 wound on the rotating wheel 120 by pulling of the bowstring 140 is released from the rotating wheel 120. Here, since the rotating wheel 120 is rotatably coupled to the rotating shaft 101 separately from the pulley 110, friction between the cam cable 150 and the rotating wheel 120 is reduced to thus reduce the force needed to pull the bowstring 140.

Meanwhile, the example applied to the compound bow of the dual cam system has been described as the embodiment of the present invention, but an example applied to a compound bow of one & a half (1&½) cam system may be employed as another embodiment of the present invention. Although not shown, in the case that the present invention is applied to a compound bow of 1&½ cam system, a pulley assembly that is coupled between the respective limbs 103 will be described below. A lower pulley assembly that is coupled between the respective lower limbs 103 is the same as the pulley assembly of the embodiment shown in FIGS. 4 and 6. That is, the lower pulley assembly includes: the pulley 110; the cam 200 which is coupled to one side of the pulley 110; the rotating wheel 120 which is coupled to the other side of the pulley 110; and the cam cable guide member 300.

However, the upper pulley assembly includes: the pulley 110; and the cam 200 which is coupled to the pulley 110. Accordingly, one end of one of the cam cables 150 is coupled to the rotating shaft of the upper pulley assembly in a buss cable form, and the other end thereof is coupled to one side surface of the lower pulley 110 so as to be wound on the cam 200 of the lower pulley assembly. In addition, one end of the other of the cam cables 150 is coupled to one side surface of the pulley 110 of the upper pulley assembly so as to be wound on the cam 200 of the upper pulley assembly, and the other end thereof is wound on the rotating wheel 120 of the lower pulley assembly and coupled to the other side surface of the pulley 110. Both ends of the bowstring 150 are wound on and coupled to the respective pulleys.

As described above, even in the case that the present invention is applied to the compound bow of the 1&½ cam system, a configuration of the lower pulley assembly is the same as the previous embodiment, and may have the same effect as the lower pulley assembly.

Next, a compound bow according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a side view showing a compound bow according to a second embodiment of the present invention before a bowstring is pulled.

FIG. 10 is a detailed view of a pulley assembly that is coupled to one of limbs in FIG. 9. FIG. 11 is a side view showing a compound bow according to the second embodiment of the present invention after a bowstring has been pulled. FIG. 12 is a detailed view of a pulley assembly in FIG. 11. FIG. 13 is a side view of the pulley assembly of FIG. 12 seen from the rear side of the compound bow.

The description of the compound bow according to the second embodiment of the present invention focuses on a different configuration from the description of the first embodiment of the present invention. In the compound bow according to the second embodiment of the present invention, the cam 200 is coupled to one side of each pulley 110 and is rotated with rotation of the pulley 110 to thus make the cam cables 150a and 150b wound on the cam 200, and includes: a cam cable winding portion 210 fabricated in an arc-shaped form and on which the cam cables 150a and 150b are wound; and a cam module 220 that is rotatably coupled to the pulley 110 by a predetermined angle from the cam cable winding portion 210, around a pivot point “A” at a position spaced by a predetermined distance from the rotating shaft 101 of the pulley 110 to which the cam 200 is coupled, in which a cam cable winding groove is formed on the outer circumferential surface of the cam module 220, and the cam cables 150a and 150b are wound around the cam cable winding portion 210 and then sequentially wound on the outer circumferential surface of the cam module 220 when the bowstring 140 is pulled.

In addition, the cam 200 further includes a fixing unit that makes the cam module 220 rotated by a predetermined angle around the pivot point “A” in order to control the draw length of the let-off state of the compound bow, and that makes the cam module 220 fixed to the pulley 110 at a position where the cam module 220 has been rotated.

The fixing unit makes the cam module 220 rotated by a predetermined angle around the pivot point “A,” and makes the cam module 220 fixed to the pulley 110 at a position where the cam module 220 has been rotated. To this end, an arc-shaped positioning hole 230 centered at the pivot point “A” is formed in the cam module 220, and a coupling hole (not shown) is formed in the pulley 110 to which the cam module 220 is coupled. Thus, when the cam module 220 is rotated by a predetermined angle around the pivot point “A,” and a coupling member 115 is coupled to the coupling hole (not shown) formed in the pulley 110 at a predetermined position of the positioning hole 230, the cam module 220 is coupled to the pulley 110. In the present invention, when a bolt as the coupling member 115 is inserted into the positioning hole 230 and is screw-coupled into the coupling hole (not shown) formed in the pulley 110, the cam module 220 is coupled to the pulley 110. In addition, an arc-shaped coupling hole 116 centered at the pivot point “A” likewise is formed in the pulley 110 as an additional fixing unit, and a bolt 117 is coupled to a bolt hole formed at a predetermined position in the cam module 220. When the bolt 117 passes through the arc-shaped coupling hole 116 formed in the pulley 110 and a nut is coupled to one end of the bolt 117, the cam module 220 is additionally secured to the pulley 110.

The cam module 220 having such a structure can adjust the draw length of the bowstring 140. Thus, when the cam module 220 of the upper and lower pulley assemblies 107 and 108 are identically rotated by an identical angle from the cam cable winding portion 210 around the pivot point “A” and the cam module 220 is again secured to the pulley 110 at a position where the cam module 220 has been rotated, the length of the cam cables 150a and 150b that are wound on the gentle slope portion 222 of the cam module 220 increases in comparison with the previous state. At last, the length of the cam cables 150a and 150b that are wound from the cam cable winding portion 210 to the cam module 220 until the let-off state increases, to thereby increase the draw length of the bowstring 140.

As shown in FIGS. 9 to 13, the cam cable guide member 300 according to the second embodiment plays a role of guiding a portion of the cam cables 150a and 150b extended from the rotating wheel 120 in parallel with the pulley 110, and is rotatably coupled to the rotating shaft 101 of the pulley 110 separately from the pulley 110 at one side surface of the rotating wheel 120, so as to be extended by a predetermined length in an arc-shaped form along the direction of extension of the cam cables 150a and 150b. As shown in FIG. 13, two coupling units 301 are protrudingly formed at one end of the cam cable guide member 300 in order to couple the rotating shaft 101 to the cam cable guide member 300, and through-holes through which the rotating shaft 101 of the pulley 110 is coupled are formed in the coupling units 301, respectively. Thus, the two coupling units 301 are coupled to the rotating shaft 101 at both sides of one branch adjacent to the rotating wheel 120 of the two branches forming the rear portion of each limb 103. In addition, the support member 310 that supports the cam cables 150a and 150b is formed at the other end of the cam cable guide member 300, in order to make a portion of the cam cables 150a and 150b that are wound on the rotating wheel 120 and then extended therefrom guided in parallel with the pulley 110. The reason why the cam cable guide member 300 is made in an arch-shaped form is that since the cam cables 150a and 150b are bent to the other side surface of the pulley 110 in order to be inserted into the cable guard 105 past the guide pulley 320, and thus the other end of the cam guide cable guide member 300 in which the support member 310 is formed, is subjected to receive a force in the opposite side of the pulley 110, the cam cable guide member 300 is made in an arch-shaped form to make the length of the cam cable guide member 300 be long while making the distance from the rotating shaft 101 to the support member 310 be short, to thereby improve a counteraction force against the force applied to the pulley 110 and prevent a deformity such as bending of the cam cable guide member 300.

The support member 310 of the cam cable guide member 300 includes a guide pulley 320 and a support pulley 330 that are respectively rotatably coupled to two shaft members 302 and 303 respectively located at both sides of the cam cables 150a and 150b, in which the cam cables 150a and 150b are supported between the guide pulley 320 and the support pulley 330. The guide pulley 320 plays a role of guiding the cam cables 150a and 150b to be guided in parallel with the pulley 110, and is rotatably coupled to the shaft member 302 that is protruded toward the pulley 110 at the other end of the cam cable guide member 300, in which a guide groove 311 for guiding the cam cables 150a and 150b is formed on the outer circumferential surface of the guide pulley 320. The guide pulley 320 is formed closer to the rotating shaft 101 than the support pulley 330.

The support pulley 330 plays a role of guiding the cam cables 150a and 150b to be guided in parallel with the pulley 110, together with the guide pulley 320, and simultaneously guiding the cam cables 150a and 150b to be guided toward the cable guard 105 via the support pulley 330. The support pulley 330 is formed farther from the rotating shaft 101 at the front of the guide pulley 320 than the guide pulley 320, and is rotatably coupled to the shaft member 303 that is protruded toward the pulley 110 at the other end of the cam cable guide member 300.

Since the cam cable guide member 300 is configured to have the above-described structure, the cam cables 150a and 150b do not come into contact with the pulley 110 and the cam cables 150a and 150b are also guided in parallel with the pulley 110 when the bowstring 140 is pulled. As a result, direction of a force applied to each of the cam cables 150a and 150b is parallel to the bowstring 140, thereby preventing distortion of the bow limbs 103.

Here, a detailed description thereof will be omitted for other configurations and operational effects of the second embodiment similar to those of the first embodiment.

As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one who has an ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. Thus, the protective scope of the present invention is not defined within the detailed description thereof but is defined by the claims to be described later and the technical spirit of the present invention.

Number	Date	Country	Kind
10-2013-0100228	Aug 2013	KR	national
10-2013-0164958	Dec 2013	KR	national

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