Archery bow modular cam system

Abstract

A modular cam system for an archery bow or crossbow includes swappable cams that change the maximum draw weight of the archery bow or crossbow. Moreover, the modular cams can be affixed to a rotatable member in a number of orientations to set the desired draw length without changing the limbs, tightening or loosening limb bolts, or disassembling the bow. Further, the maximum draw weight of the bow remains substantially similar throughout a large portion of the draw length adjustment for a specified cam module.

1 . An archery bow comprising:
 a riser, a first limb supporting a first rotatable member and a second limb supporting a second rotatable member;   the first rotatable member comprising a body comprising a bowstring track and a first cam module attached to the body, the first cam module comprising a power cable track;   a bowstring extending from the first rotatable member to the second rotatable member;   a power cable arranged to contact the first cam module; and   a second cam module interchangeable with the first cam module;   wherein the first cam module and the second cam module each comprise a high weight portion and a let-off portion, the high weight portion of the first cam module shaped differently from the high weight portion of the second cam module, the let-off portion of the first cam module shaped similarly to the let-off portion of the second cam module.   
     
     
         2 . The archery bow of  claim 1 , wherein a peak draw force provided by the high weight portion of the first cam module is different from a peak draw force provided by the high weight portion of the second cam module, and a reduction in draw force provided by the let-off portion of the first cam module is similar to a reduction in draw force provided by the let-off portion of the second cam module. 
     
     
         3 . The archery bow of  claim 1 , the high weight portion of the first cam module comprising an arc having a first radius, the high weight portion of the second cam module comprising an arc having a second radius different from the first radius. 
     
     
         4 . The archery bow of  claim 1 , the first cam module attachable to the body in a first orientation to provide a first draw length, the first cam module attachable to the body in a second orientation to provide a second draw length different from the first draw length. 
     
     
         5 . The archery bow of  claim 4 , wherein the second orientation comprises a rotation of the first orientation. 
     
     
         6 . The archery bow of  claim 4 , the second cam module attachable to the body in a first orientation to provide a first draw length, the second cam module attachable to the body in a second orientation to provide a second draw length different from the first draw length. 
     
     
         7 . The archery bow of  claim 1 , the first cam module comprising a draw stop. 
     
     
         8 . The archery bow of  claim 7 , the draw stop arranged to contact the power cable. 
     
     
         9 . The archery bow of  claim 1 , further comprising a third cam module interchangeable with the first cam module, the third cam module comprising a high weight portion shaped differently from the high weight portion of the first cam module and shaped differently from the high weight portion of the second cam module, the third cam module comprising a let-off portion shaped similarly to the let-off portion of the first cam module. 
     
     
         10 . The archery bow of  claim 1 , the power cable comprising a first power cable, the first cam module comprising an upper first cam module, the archery bow further comprising a second power cable, the second rotatable member comprising a lower first cam module arranged to contact the second power cable, the lower first cam module comprising a high weight portion shaped similarly to the high weight portion of the upper first cam module. 
     
     
         11 . The archery bow of  claim 10 , the lower first cam module comprising a let-off portion shaped differently from the let-off portion of the upper first cam module. 
     
     
         12 . An archery bow kit comprising:
 a riser and opposed limbs, each limb supporting a rotatable member;   at least one rotatable member comprising a body and a first cam module, said body defining a bowstring payout track, said cam module defining a power cable take-up track;   said kit further comprising a second cam module suitable for replacing said first cam module, each of said cam modules comprising a let-off portion and a peak weight portion, the peak weight portion of said second cam module being larger than the peak weight portion of said first cam module;   wherein a peak draw weight of said bow using said first cam module is less than a peak draw weight of said bow using said second cam module and the let-off portions of said first and said second cam modules each produce at least 45% let-off in draw weight.   
     
     
         13 . The bow kit of  claim 12 , wherein said first cam module is adjustable with respect to said rotatable member body between first and second orientations, a draw length of said bow with said first cam module in said first orientation is different from a draw length of said bow with said first cam module in said second orientation, a peak draw weight of said bow with said first cam module in said first orientation is substantially similar to a peak draw weight of said bow with said first cam module in said second orientation. 
     
     
         14 . The bow kit of  claim 13 , wherein said draw length changes at least six inches between said first orientation and said second orientation. 
     
     
         15 . The bow kit of  claim 13 , wherein said second cam module is adjustable with respect to said rotatable member body between first and second orientations, a draw length of said bow with said second cam module in said first orientation is different from a draw length of said bow with said second cam module in said second orientation, a peak draw weight of said bow with said second cam module in said first orientation is substantially similar to a peak draw weight of said bow with said second cam module in said second orientation. 
     
     
         16 . The bow kit of  claim 15 , wherein said draw length changes at least six inches between said first orientation and said second orientation.