Patent ID: 8281773
Filing Date: 2012-10-09
Classification: F41B

Abstract:
1. A compound bow comprising, in combination, (a) a riser body having reflectively symmetrical, upper and lower bow-limb mount faces at end, each having a front, threaded, deep anchor receptacle penetrating into the riser body for receiving a bow-limb attachment bolt and a back, transverse, concave semi-cylindrical relief having a radius r, both the receptacle and the relief being bisected by a central, vertical bow reference plane; (b) a pair of reflectively symmetrical, shouldered, concave, semi-cylindrical ear structures of radius r, positioned and coaxially secured at opposite ends of each back, transverse concave, semi-cylindrical relief, transversely sandwiching each end of the riser body providing, in combination with the concave semi-cylindrical relief, a transverse concave, semi-cylindrical limb-pod cradle of radius r, having constraining, vertical, bow-limb aligning, end-shoulders extending vertically at each end above a cylindrical volume defined by the radius, r, of the limb-pod cradle; (c) a limb-pod cylinder composed of a resilient synthetic engineering polymer material having a radius and length adjusted for snugly fitting in each limb-pod cradle, providing at least a convex, hemicylindrical flexure surface above the bow-limb mount face of the riser body; (d) matched upper and lower bow-limbs each having an anchor end, a flexure section and a yoke end, bisected by a longitudinal central reference plane wherein: (e) a limb-top trim structure adapted to seat on top of the anchor end of the each bow-limb, for coupling the respective upper and lower bow-limbs to the riser body at its upper and lower mount faces, each limb-top trim structure having: (f) an idler pulley presenting an idler cable race secured and supported for rotation in the bow reference plane around the pulley axle spanning between the yoke arms of the upper bow-limb coupled to the upper end-mount of the riser body; (g) a dual-cam, power pulley secured and supported for rotation in the bow reference plane around the axle spanning between the yoke arms of the lower bow-limb coupled to the lower end-mount of the riser body having a power lobe cam presenting a power cable race spiraling outward on a side face of an elliptical draw lobe cam that in turn, presents a draw-lobe cable race; (h) a drawstring cable looped around the idler cable race of the idler pulley having an inside segment cable end anchored and journaled for unwinding from, and winding-up around the power cam cable race of the power lobe cam of the dual cam power pulley, and having an outside cable segment end anchored and journaled for unwinding from, and winding-up around the draw-lobe cable race of the elliptical draw lobe cam of dual cam power pulley as the outside drawstring cable segment is drawn and released for launching an arrow nocked at a nock point of the outside drawstring cable segment; (i) a power cable having a yoke end presenting a pair of loops for anchoring around ends of the axle of the idler/control pulley extending through the yoke arms of the upper bow limb, and a fastened end anchored and journaled for winding-up and unwinding from around the power cable race of the power lobe cam of the dual-cam power pulley rotating as the outside drawstring cable respectively unwinds from and winds-up around the draw-lobe cable race of the elliptical draw lobe cam and the power cable race of the power lobe cam as the drawstring cable is drawn and released for launching an arrow nocked at its nock point; whereby, the upper and lower bow limbs are functionally coupled to the riser body at its upper and lower bow-limb mount faces by the limb-top trim structures pivotally coupling to the bow-limb attachment bolts and flexure of the bow-limbs around the convex, hemicylindrical flexure surface of the limb-pod cylinder within the limb-pod cradle tensioning the drawstring and power cables; and whereby, brace tension in both the power cable and the drawstring cable may be increased and relieved by contemporaneously screwing and unscrewing the bow-limb attachment bolts into and out of the front, deep threaded anchor receptacles penetrating into the riser body at the bow-limb mount faces for adjusting flexure of the flexure sections of the upper and lower bow limbs around limb-pod cylinders within the limb-pod cradles.