Pulley-and-cable power cable tensioning mechanism for a compound archery bow
View Patent ↗A bow comprises: a riser; first and second limbs attached to the riser; first and second pulley members rotatably connected to the respective bow limbs; draw, power, and tensioning cables; and a tensioning pulley. The draw cable engages draw cable journals of the pulley members and rotates them as the bow is drawn and the draw cable is let out from the draw cable journals. The tensioning cable is secured at its first end to the first bow limb and engaged at its second end to be taken up by a power cam of the first pulley member as the bow is drawn and the first pulley member rotates. The tensioning pulley includes a tensioning cable journal and is arranged with the tensioning cable engaged therewith. The power cable is connected at its first end to the tensioning pulley and at its second end to the second bow limb.
1. A compound archery bow comprising:
a substantially rigid riser having first and second end portions;
a first resilient bow limb attached to the first end portion of the riser, which first bow limb has a corresponding pulley connection point;
a second resilient bow limb attached to the second end portion of the riser, which second bow limb has a corresponding pulley connection point;
a first pulley member rotatably connected to the first bow limb at the corresponding pulley connection point, which first pulley member includes a draw cable journal and a first power cam;
a second pulley member rotatably connected to the second bow limb at the corresponding pulley connection point, which second pulley member includes a draw cable journal;
a draw cable engaged with the respective draw cable journals of the first and second pulley members and arranged to rotate the first and second pulley members as the bow is drawn and the draw cable is let out from the draw cable journals;
a first tensioning cable secured at a first end thereof to the first bow limb and engaged at a second end thereof to be taken up by the first power cam as the bow is drawn and the first pulley member rotates;
a first tensioning pulley, which tensioning pulley includes a corresponding tensioning cable journal and is arranged with the first tensioning cable engaged with the corresponding tensioning cable journal; and
a first power cable connected at a first end thereof to the first tensioning pulley and connected at a second end thereof to the second bow limb.
2. The bow of claim 1 wherein the second pulley member includes a second power cam, and the bow further comprises:
a second tensioning cable secured at a first end thereof to the second bow limb and engaged at a second end thereof to be taken up by the second power cam as the bow is drawn and the second pulley member rotates;
a second tensioning pulley, which tensioning pulley includes a corresponding tensioning cable journal and is arranged with the second tensioning cable engaged with the corresponding tensioning cable journal; and
a second power cable connected at a first end thereof to the second tensioning pulley and connected at a second end thereof to the first bow limb.
3. The bow of claim 2 wherein:
the first pulley member further includes a corresponding power cable let-out mechanism;
the second pulley member further includes a corresponding power cable let-out mechanism;
the first power cable is connected to the second bow limb by engagement with the power cable let-out mechanism of the second pulley member so that the first power cable is let out as the bow is drawn and the second pulley member rotates; and
the second power cable is connected to the first bow limb by engagement with the power cable let-out mechanism of the first pulley member so that the second power cable is let out as the bow is drawn and the first pulley member rotates.
4. The bow of claim 3 wherein each power cable let-out mechanism comprises a corresponding power cable let-out journal.
5. The bow of claim 1 wherein:
the first pulley member includes a let-out journal;
the second pulley member comprises an idler wheel with the draw cable journal; and
the draw cable passes over the draw cable journal of the idler wheel and is engaged with and arranged to be let out from the let-out journal of the first pulley member as the bow is drawn and the first pulley member rotates.
6. The bow of claim 1 wherein:
the first pulley member includes a bus cable journal;
the second pulley member includes a bus cable journal;
the bow further comprises a bus cable;
the bus cable is engaged with and arranged to be let out from the bus cable journal of the first pulley member as the bow is drawn and the first pulley member rotates; and
the bus cable is engaged with and arranged to be taken up by the bus cable journal of the second pulley member as the bow is drawn and the second pulley member rotates.
7. The bow of claim 1 wherein the first end of the first tensioning cable comprises two split portions, and the split portions each loop around an axle of the first pulley member on opposite sides of the first bow limb, thereby securing the first end of the tensioning cable to the first bow limb.
8. The bow of claim 1 further comprising a coupler having a pair of substantially parallel pins connected together in a substantially rigid spaced-apart arrangement, wherein the first tensioning pulley is rotatably mounted on one pin and the first end of the first power cable loops around the other pin, thereby connecting the first end of the power cable to the first tensioning pulley.
9. The bow of claim 1 wherein the first end of the first power cable comprises two split portions, and the split portions each loop around an axle of the first tensioning pulley on opposite sides thereof, thereby connecting the first end of the power cable to the first tensioning pulley.
10. A method for assembling a compound archery bow, the method comprising:
rotatably connecting a first pulley member to a first bow limb at a corresponding pulley connection point thereof, which first pulley member includes a draw cable journal and a first power cam, wherein the first bow limb is attached to a first end portion of a substantially rigid riser;
rotatably connecting a second pulley member to a second bow limb at a corresponding pulley connection point thereof, which second pulley member includes a draw cable journal, wherein the second bow limb is attached to a second end portion of the riser;
engaging a draw cable with the respective draw cable journals of the first and second pulley members and arranging the draw cable to rotate the first and second pulley members as the bow is drawn and the draw cable is let out from the draw cable journals;
securing a first tensioning cable at a first end thereof to the first bow limb and engaging the first tensioning cable at a second end thereof to be taken up by the first power cam as the bow is drawn and the first pulley member rotates;
connecting a first power cable at a first end thereof to a first tensioning pulley and connecting the first power cable at a second end thereof to the second bow limb; and
engaging the first tensioning cable with a corresponding tensioning cable journal of the first tensioning pulley.
11. The method of claim 10 further comprising:
attaching the first bow limb to the first end portion of the riser; and
attaching the second bow limb to the second end portion of the riser.
12. The method of claim 10 wherein the second pulley member includes a second power cam, and the method further comprises:
securing a second tensioning cable at a first end thereof to the second bow limb and engaging the second tensioning cable at a second end thereof to be taken up by the second power cam as the bow is drawn and the second pulley member rotates;
connecting a second power cable at a first end thereof to a second tensioning pulley and connecting the second power cable at a second end thereof to the first bow limb; and
engaging the second tensioning cable with a corresponding tensioning cable journal of the second tensioning pulley.
13. The method of claim 12 wherein:
the first pulley member further includes a power cable let-out mechanism;
the second pulley member further includes a power cable let-out mechanism;
connecting the first power cable to the second bow limb comprises engaging the first power cable with the power cable let-out mechanism of the second pulley member so that the first power cable is let out as the bow is drawn and the second pulley member rotates; and
connecting the second power cable to the first bow limb comprises engaging the second power cable with the power cable let-out mechanism of the first pulley member so that the second power cable is let out as the bow is drawn and the first pulley member rotates.
14. The method of claim 13 wherein each power cable let-out mechanism comprises a corresponding power cable let-out journal.
15. The method of claim 10 wherein:
the first pulley member includes a let-out journal;
the second pulley member comprises an idler wheel with the draw cable journal; and
the method further comprises passing the draw cable over the draw cable journal of the idler wheel, engaging the draw cable with the let-out journal of the first pulley member, and arranging the draw cable to be let out from the let-out journal of the first pulley member as the bow is drawn and the first pulley member rotates.
16. The method of claim 10 wherein:
the first pulley member includes a bus cable journal;
the second pulley member includes a bus cable journal; and
the method further comprises engaging a bus cable with the bus cable journal of the first pulley member, arranging the bus cable to be let out from the bus cable journal of the first pulley member as the bow is drawn and the first pulley member rotates, engaging the bus cable with the bus cable journal of the second pulley member, and arranging the bus cable to be taken up by the bus cable journal of the second pulley member as the bow is drawn and the second pulley member rotates.
17. The method of claim 10 wherein securing the first end of the tensioning cable to the first bow limb comprises looping around an axle of the first pulley member on opposite sides of the first bow limb two split portions that comprise the first end of the first tensioning cable.
18. The method of claim 10 wherein connecting the first end of the power cable to the first tensioning pulley comprises (i) rotatably mounting the first tensioning pulley on one of a pair of substantially parallel pins connected together in a substantially rigid spaced-apart arrangement by a coupler, and (ii) looping the first end of the first power cable around another pin of the pair.
19. The method of claim 10 wherein connecting the first end of the power cable to the first tensioning pulley comprises looping around an axle of the first tensioning pulley on opposite sides thereof two split portions that comprise the first end of the first power cable.