Bowstring Cam Arrangement for Compound Long Bow or Crossbow
First Claim
1. A bow comprising a riser, pair of power limbs or spring limbs disposed one at each end of the riser;
- cam wheels each pivotally mounted at a pivot at a free end of each of the power limbs;
the cam wheels each having a bowstring groove wherein a bowstring is reeved to each of the cam wheels and travels in the respective bowstring grooves to be wound and unwound therefrom, and upper and lower power cord cam grooves disposed axially above and below the associated bowstring groove of the cam wheel;
power cords which are flexible and inextensible and are wound into the power cord cam grooves; and
anchor members affixed to the respective side of a medial plane corresponding to the arrow axis;
wherein the power cords are affixed at ends remote from the cam wheel into the respective anchor member, such that none of the power cords extend across the medial plane to the other limb; and
wherein the power cord cam grooves and the bowstring cam grooves are programmed such that the draw weight on the bow string increases from full brace position to full draw position without weight drop-off.
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Accused Products
Abstract
A compound bow or crossbow employs bowstring cams with bowstring cam grooves and power cord cam grooves. Preferably a pair of generally identical power cord cam grooves are positioned axially above and below the bowstring cam groove. The power cords are anchored to a fixed anchor point, e.g., a pylon, on the near end of the riser or on the near side of the crossbow bar or stock. The power cords do not cross over to the other limb. The reduction in the number of cam wheels and pulleys and in the number of strings or cords results in greater efficiency and higher transfer of energy from the bow to the arrow or bolt. There is no drop-off in pull weight at full draw. The bolt or arrow accelerates throughout the travel of the bowstring, resulting in significantly higher velocity.
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Citations
2 Claims
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1. A bow comprising a riser, pair of power limbs or spring limbs disposed one at each end of the riser;
- cam wheels each pivotally mounted at a pivot at a free end of each of the power limbs;
the cam wheels each having a bowstring groove wherein a bowstring is reeved to each of the cam wheels and travels in the respective bowstring grooves to be wound and unwound therefrom, and upper and lower power cord cam grooves disposed axially above and below the associated bowstring groove of the cam wheel;
power cords which are flexible and inextensible and are wound into the power cord cam grooves; and
anchor members affixed to the respective side of a medial plane corresponding to the arrow axis;
wherein the power cords are affixed at ends remote from the cam wheel into the respective anchor member, such that none of the power cords extend across the medial plane to the other limb; and
wherein the power cord cam grooves and the bowstring cam grooves are programmed such that the draw weight on the bow string increases from full brace position to full draw position without weight drop-off.
- cam wheels each pivotally mounted at a pivot at a free end of each of the power limbs;
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2. A crossbow comprising a stock situated at a medial plane of the crossbow, a riser at a distal end of the stock, pair of power limbs or spring limbs disposed one at each end of the riser;
- cam wheels each pivotally mounted at a pivot at a free end of each of the power limbs;
the cam wheels each having a bowstring groove wherein a bowstring is reeved to each of the cam wheels and travels in the respective bowstring grooves to be wound and unwound therefrom, and upper and lower power cord cam grooves disposed axially above and below the associated bowstring groove of the cam wheel;
power cords which are flexible and inextensible and are wound into the power cord cam grooves; and
anchor members affixed to the respective side of the medial plane corresponding to the crossbow bolt axis;
wherein the power cords are affixed at ends remote from the cam wheel into the respective anchor member, such that none of the power cords extend across the medial plane to the other limb; and
wherein the power cord cam grooves and the bowstring cam grooves are programmed such that the draw weight on the bow string increases from full brace position to full draw position without weight drop-off.
- cam wheels each pivotally mounted at a pivot at a free end of each of the power limbs;
Specification