Crossbow with power cable

Abstract

The crossbow includes a center rail, and a first flexible limb and a second flexible limb coupled with the center rail. The crossbow includes a first cam and a second cam rotatably coupled with the first flexible limb and the second flexible limb, respectively. The crossbow includes a draw string coupled with first cam and the second cam. The first cam and the second cam include a power cable take-up journal. The crossbow includes a first power cable with a first end portion configured to wind about a first cam axis and second end portion configured to unwind about a second cam axis. The crossbow includes a second power cable with a first end portion configured to wind about the second cam axis and a second end portion of configured to unwind about the first axis.

What is claimed is: 
     
         1 . A crossbow comprising:
 a center rail including a rail body and a riser;   a first flexible limb including a first end and a second end, the first end coupled to the riser;   a second flexible limb including a first end and a second end, the first end coupled to the riser;   a first cam mounted to the first end of the first flexible limb for rotation about a first cam axis via a first cam axle, the first cam axis fixed relative to the first flexible limb, the first cam including:
 a first draw string journal defining a first draw string plane of rotation perpendicular to the first cam axis, and 
 a first power cable take-up journal extending in a direction perpendicular to the first draw string plane of rotation, the first power cable take-up journal including a first helical structure; 
   a second cam mounted to the second flexible limb for rotation about a second cam axis via a second cam axle, the first cam axis fixed relative to the second flexible limb, the second cam including:
 a second draw string journal defining a second draw string plane of rotation perpendicular to the second cam axis, and 
 a second power cable take-up journal extending in a direction perpendicular to the second draw string plane of rotation, the second power cable take-up journal including a second helical structure; 
   a draw string received in the first draw string journal and in the second draw string journal and secured to the first cam and the second cam, the draw string configured to move between a released configuration and a drawn configuration;   a first power cable including a first end portion and a second end portion, the first end portion of the first power cable attached to the first cam and configured to wind about the first cam axis within the first helical structure of the first power cable take-up journal, the second end portion of the first power cable attached to the second cam and configured to unwind about the second cam axis; and   a second power cable including a first end portion and a second end portion, the first end portion of the second power cable attached to the second cam and configured to wind about the second cam axis within the second helical structure of the second power cable take-up journal, the second end portion of the second power cable attached to the first cam and configured to unwind about the first cam axis;   wherein, during operation of the crossbow as the draw string moves from the released configuration to the drawn configuration, the first end portion of the first power cable is displaced away from the first draw string plane of rotation by the first helical structure of the first power cable take-up journal of the first cam;   wherein, during operation of the crossbow as the crossbow moves from the released configuration to the drawn configuration, the first end portion of the second power cable is displaced away from the second draw string plane of rotation by the second helical structure of the second power cable take-up journal of the second cam.   
     
     
         2 . The crossbow of  claim 1 , wherein the first power cable take-up journal includes a width that is greater than twice a width of the first end portion of the first power cable, and
 wherein the second power cable take-up journal includes a width that is greater than twice a width of the first end portion of the second power cable.   
     
     
         3 . The crossbow of  claim 1 , wherein the first helical structure of the first power cable take-up journal and the second helical structure of the second power cable take-up journal respectively extend in a first direction, wherein the first cam further comprises a third power cable journal including a third helical structure extending in a second direction opposite the first direction, wherein the second cam further comprises a fourth power journal including a fourth helical structure extending in the second direction. 
     
     
         4 . The crossbow of  claim 1 , wherein the first power cable has a first power cable width, wherein the first power cable take-up journal is configured to displace the first power cable along the first cam axis away from the first draw string plane of rotation by a distance greater than the first power cable width in the direction perpendicular to the first draw string plane of rotation, and
 wherein the second power cable has a second power cable width, wherein the second power cable take-up journal is configured to displace the second power cable along the second cam axis away from the second draw string plane of rotation by a distance greater than the second power cable width in the direction perpendicular to the second draw string plane of rotation.   
     
     
         5 . The crossbow of  claim 1 , wherein the first draw string plane of rotation and second draw string plane of rotation are the same. 
     
     
         6 . The crossbow of  claim 1 , further comprising:
 a first axle mount fixedly attached to the first flexible limb, wherein the first cam is rotatably coupled to the first axle mount so that the first cam axis is offset from a first limb end by a fixed offset, and   a second axle mount fixedly attached to the second flexible limb, wherein the second cam is rotatably coupled to the second axle mount so that the second cam axis is offset from a second limb end by a fixed offset.   
     
     
         7 . The crossbow of  claim 1 , wherein the first cam axis passes through the first flexible limb and wherein the second cam axis passes through the second flexible limb. 
     
     
         8 . The crossbow of  claim 1 , wherein:
 during operation of the crossbow, the first cam rotates more than 270 degrees about the first cam axis as the crossbow is moved from the released configuration to the drawn configuration; and   during operation of the crossbow, the second cam rotates more than 270 degrees about the second cam axis as the crossbow is moved from the released configuration to the drawn configuration.   
     
     
         9 . The crossbow of  claim 1 , wherein the first cam is configured to rotate  360  or fewer degrees about the first cam axis as the crossbow is moved from the released configuration to the drawn configuration, and
 wherein the second cam is configured to rotate 360 or fewer degrees about the second cam axis as the crossbow is moved from the released configuration to the drawn configuration. 
 
     
     
         10 . The crossbow of  claim 9 , wherein the first power cable take-up journal defines a length that accommodates between 270 degrees and 360 degrees of rotation of the first cam, and
 wherein the second power cable take-up journal defines a length that accommodates between 270 degrees and about 360 degrees of rotation of the second cam.   
     
     
         11 . The crossbow of  claim 1 , wherein:
 during operation of the crossbow, the second end of the first power cable winds about the second cam axis of the second cam; and   during operation of the crossbow, the second end of the second power cable winds about the first cam axis of the first cam.   
     
     
         12 . A crossbow, comprising:
 a center rail including a rail body and a riser;   a first flexible limb including a first end and a second end, the first end coupled to the riser;   a second flexible limb including a first end and a second end, the first end coupled to the riser;   a first cam mounted to the first end of the first flexible limb for rotation about a first cam axis via a first cam axle, the first cam axis fixed relative to the first flexible limb, the first cam including:
 a first draw string journal defining a first draw string plane of rotation perpendicular to the first cam axis, and 
 a first power cable take-up journal extending in a direction perpendicular to the first draw string plane of rotation, the first power cable take-up journal including a first helical structure; 
   a second cam mounted to the second flexible limb for rotation about a second cam axis via a second cam axle, the first cam axis fixed relative to the second flexible limb, the second cam including:
 a second draw string journal defining a second draw string plane of rotation perpendicular to the second cam axis, and 
 a second power cable take-up journal extending in a direction perpendicular to the second draw string plane of rotation, the second power cable take-up journal including a second helical structure; 
   a draw string received in the first draw string journal and in the second draw string journal and secured to the first cam and the second cam, the draw string configured to move between a released configuration and a drawn configuration;   a first power cable including a first end portion and a second end portion, the first end portion of the first power cable attached to the first cam and configured to wind about the first cam axis within the first helical structure of the first power cable take-up journal, the second end portion of the first power cable attached to the second cam and configured to unwind about the second cam axis; and   a second power cable including a first end portion and a second end portion, the first end portion of the second power cable attached to the second cam and configured to wind about the second cam axis within the second helical structure of the second power cable take-up journal, the second end portion of the second power cable attached to the first cam and configured to unwind about the first cam axis;   wherein, during operation of the crossbow, the first cam rotates more than  270  degrees about the first cam axis as the crossbow is moved from the released configuration to the drawn configuration;   wherein, during operation of the crossbow, the second cam rotates more than  270  degrees about the second cam axis as the crossbow is moved from the released configuration to the drawn configuration;   wherein, during operation of the crossbow as the draw string moves from the released configuration to the drawn configuration, the first end portion of the first power cable is displaced away from the first draw string plane of rotation by the first helical structure of the first power cable take-up journal of the first cam;   wherein, during operation of the crossbow as the crossbow moves from the released configuration to the drawn configuration, the first end portion of the second power cable is displaced away from the second draw string plane of rotation by the second helical structure of the second power cable take-up journal of the second cam.   
     
     
         13 . The crossbow of  claim 12 , wherein the first power cable take-up journal includes a width that is greater than twice a width of the first end portion of the first power cable, and
 wherein the second power cable take-up journal includes a width that is greater than twice a width of the first end portion of the second power cable.   
     
     
         14 . The crossbow of  claim 12 , wherein the first helical structure of the first power cable take-up journal and the second helical structure of the second power cable take-up journal respectively extend in a first direction, wherein the first cam further comprises a third power cable journal including a third helical structure extending in a second direction opposite the first direction, wherein the second cam further comprises a fourth power journal including a fourth helical structure extending in the second direction. 
     
     
         15 . The crossbow of  claim 12 , wherein the first power cable has a first power cable width, wherein the first power cable take-up journal is configured to displace the first power cable along the first cam axis away from the first draw string plane of rotation by a distance greater than the first power cable width in the direction perpendicular to the first draw string plane of rotation, and
 wherein the second power cable has a second power cable width, wherein the second power cable take-up journal is configured to displace the second power cable along the second cam axis away from the second draw string plane of rotation by a distance greater than the second power cable width in the direction perpendicular to the second draw string plane of rotation.   
     
     
         16 . The crossbow of  claim 12 , wherein:
 during operation of the crossbow, the second end of the first power cable winds about the second cam axis of the second cam; and   during operation of the crossbow, the second end of the second power cable winds about the first cam axis of the first cam.   
     
     
         17 . A crossbow, comprising:
 a center rail including a rail body and a riser;   a first flexible limb including a first end and a second end, the first end coupled to the riser;   a second flexible limb including a first end and a second end, the first end coupled to the riser;   a first cam mounted to the first end of the first flexible limb for rotation about a first cam axis via a first cam axle, the first cam axis fixed relative to the first flexible limb, the first cam including:
 a first draw string journal defining a first draw string plane of rotation perpendicular to the first cam axis, and 
 a first power cable take-up journal extending in a direction perpendicular to the first draw string plane of rotation, the first power cable take-up journal including a first helical structure; 
   a second cam mounted to the second flexible limb for rotation about a second cam axis via a second cam axle, the first cam axis fixed relative to the second flexible limb, the second cam including:
 a second draw string journal defining a second draw string plane of rotation perpendicular to the second cam axis, and 
 a second power cable take-up journal extending in a direction perpendicular to the second draw string plane of rotation, the second power cable take-up journal including a second helical structure; 
   a draw string received in the first draw string journal and in the second draw string journal and secured to the first cam and the second cam, the draw string configured to move between a released configuration and a drawn configuration;   a first power cable including a first end portion and a second end portion, the first end portion of the first power cable attached to the first cam and configured to wind about the first cam axis within the first helical structure of the first power cable take-up journal, the second end portion of the first power cable attached to the second cam and configured to unwind about the second cam axis; and   a second power cable including a first end portion and a second end portion, the first end portion of the second power cable attached to the second cam and configured to wind about the second cam axis within the second helical structure of the second power cable take-up journal, the second end portion of the second power cable attached to the first cam and configured to unwind about the first cam axis;   wherein, during operation of the crossbow, the first cam rotates more than  270  degrees about the first cam axis as the crossbow is moved from the released configuration to the drawn configuration;   wherein, during operation of the crossbow, the second cam rotates more than  270  degrees about the second cam axis as the crossbow is moved from the released configuration to the drawn configuration;   wherein, during operation of the crossbow as the draw string moves from the released configuration to the drawn configuration, the first end portion of the first power cable is displaced away from the first draw string plane of rotation by the first helical structure of the first power cable take-up journal of the first cam, and the second end of the first power cable unwinds about the second cam axis of the second cam;   wherein, during operation of the crossbow as the crossbow moves from the released configuration to the drawn configuration, the first end portion of the second power cable is displaced away from the second draw string plane of rotation by the second helical structure of the second power cable take-up journal of the second cam, and the second end of the second power cable unwinds about the first cam axis of the first cam.   
     
     
         18 . The crossbow of  claim 17 , wherein the first power cable take-up journal includes a width that is greater than twice a width of the first end portion of the first power cable, and
 wherein the second power cable take-up journal includes a width that is greater than twice a width of the first end portion of the second power cable.   
     
     
         19 . The crossbow of  claim 17 , wherein the first helical structure of the first power cable take-up journal and the second helical structure of the second power cable take-up journal respectively extend in a first direction, wherein the first cam further comprises a third power cable journal including a third helical structure extending in a second direction opposite the first direction, wherein the second cam further comprises a fourth power journal including a fourth helical structure extending in the second direction. 
     
     
         20 . The crossbow of  claim 17 , wherein the first power cable has a first power cable width, wherein the first power cable take-up journal is configured to displace the first power cable along the first cam axis away from the first draw string plane of rotation by a distance greater than the first power cable width in the direction perpendicular to the first draw string plane of rotation, and
 wherein the second power cable has a second power cable width, wherein the second power cable take-up journal is configured to displace the second power cable along the second cam axis away from the second draw string plane of rotation by a distance greater than the second power cable width in the direction perpendicular to the second draw string plane of rotation.