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US 4,541,401 AGranted
Compound archery bow
OwnerJoseph M. Caldwellinventor
Life of this patent
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OwnerJoseph M. Caldwellinventor
Estimating the term…
An archer's compound shooting bow has rigging cables and pulleys arranged to eliminate torque on the limbs when the bow is fully drawn and to permit an arrow to fly true past the rigging when the bow approaches its rest condition. Each pulley has two grooves receiving an adjacent rigging cable. The grooves have variable separation at different locations along the pulley rim. Each pulley is mounted on a limb alongside the opposite rigging cable dead end. As to each limb, the connection of the opposite cable dead end and the location of the adjacent cable tensions are arranged, in respect to their magnitudes at full draw, to apply no net torsional moment to the limb about its torsional axis. The separation between the pulley grooves corresponding to the rest condition permits arrow feathers to pass the rigging cables without contact, which is not true at full draw. The groove for the shooting string is normal to the pulley rotational axis. The other groove is substantially helical to the first groove. The pulley is ring-shaped and is fabricated from an extrusion having an annular cross section.
In a compound archery bow in which a first rigging cable having a live end and a dead end is reeved on and through an eccentric pulley to provide cable shooting and bus portions disposed on opposite sides of the pulley and associated respectively with the first cable live and dead ends, the pulley having two cable grooves defined in the circumference thereof, one of the grooves being spaced from the other along an axis of rotation of the pulley defined by an axle mounted to a movable end of an elongate bow limb arranged to deflect in bending from a relaxed state to a drawn state in response to drawing of a bowstring, the bowstring being connected at one end thereof to the live end of the first cable and at an opposite end thereof to a live end of an opposite rigging cable, the bow having means for connecting a dead end of the opposite rigging cable to the limb, the axle extending transversely of a torsional axis of the limb, each of the first cable shooting and bus portions having an effective point of application of load on the axle, the improvement comprising means, including the pulley and its geometry, for connecting the first rigging cable to the pulley and the opposite cable dead end to the axle in which, in the drawn state of the bowstring, the locations of the effective points of application of the first rigging cable tension loads to the pulley, and of the opposite cable dead end load on the axle, are cooperatively related to each other, to the location of the adjacent limb torsional axis, and to the magnitudes of said loads so as (1) to impose on the limb an insignificant moment about its torsional axis, and (2) to preserve such insignificant moment throughout the deflection of the limbs corresponding to movement of the bowstring for a substantial distance from the drawn state thereof.
In a compound archery bow in which a first rigging cable having a live end and a dead end is reeved on and through an eccentric pulley to provide cable shooting and bus portions disposed on opposite sides of the pulley and associated respectively with the first cable live and dead ends, the pulley has two cable grooves defined in the circumference thereof, one of the grooves being spaced from the other along an axis of rotation of the pulley defined by an axle mounted to a movable end of an elongate bow limb arranged to deflect in bending in response to drawing of a bowstring from a relaxed state to a drawn state, the bowstring being connected at one end thereof to the live end of the first cable and at an opposite end thereof to a live end of an opposite rigging cable, the bow includes means for connecting a dead end of the opposite rigging cable to the limb, the axle extends transversely of a torsional axis of the limb, each of the first cable shooting and bus portions has a point of application of first rigging cable tension load to the pulley, and the opposite cable end has a point of application of opposite cable tension load on the axle, the improvement comprising means including the pulley and its geometry for connecting the first rigging cable to the pulley and the opposite cable dead end to the axle in which the resultant of (1) the first rigging cable tension loads to the pulley and (2) the opposite cable dead end load on the axle is substantially aligned with the limb torsional axis, both at the fully drawn state of the bowstring and during a substantial portion of the movement of the bowstring upon release from said fully drawn state.
In a compound archery bow having a shooting string and a pair of limbs each flexible in bending and torsion respectively along and about a torsional axis along the limb, an eccentric pulley mounted to the end of each limb for rotation about an axle connected to the limb and defining a pulley rotational axis disposed transversely of the limb torsional axis, and a rigging cable reeved on each pulley between a shooting string end associated with the pulley and a dead end thereof associated with the opposite limb, each cable being a corresponding cable with respect to the pulley on which it is reeved and an opposite cable with respect to the other pulley, each cable between the shooting string end and the pulley having a shooting portion associated with the pulley, each cable between the dead end and the pulley having a bus portion extending from the pulley to the opposite limb of the bow past the path of movement of a fletched arrow upon release of the shooting string, connected between the shooting string ends of the cables, from a drawn state thereof displaced from a relaxed state thereof, each pulley defining in the periphery thereof a first shooting groove for receiving a part of the shooting portion of the corresponding cable and a second bus groove for receiving a part of the bus portion of the corresponding cable, at least the shooting groove being defined in a plane normal to the pulley rotational axis, the grooves on each pulley being spaced from each other along the pulley rotational axis, the improvement comprising means including the pulley and its geometry for coupling the corresponding cable bus and shooting portions and opposite cable dead end to the adjacent limb to prevent torsion of the limb at full draw of the shooting string and in which, as to each limb, in the said drawn state the location of application of the opposite cable dead end tension to the limb and of the locations of application of the adjacent corresponding cable bus portion and shooting portion tensions on the axle are arranged, in combination with the magnitudes of such tensions in the said drawn state and in relation to the location of the limb torsional axis, to apply no significant net torsional movement of the limb about the limb torsional axis, and including means for moving the location of application of the adjacent corresponding cable bus portion tension along the pulley axis to substantially maintain said condition of no significant net torsional movement of the limb about its torsional axis from a drawn condition to substantially the relaxed string condition of the bow.
In a compound archery bow having a shooting string and a shooting string and a pair of limbs each flexible in bending and torsion along and about a torsional axis of the limb, an eccentric pulley mounted to the end of each limb for rotation about an axle connected to the limb and defining a pulley rotational axis disposed transversely of the limb torsional axis, and a rigging cable reeved on each pulley between a shooting string end associated with the pulley and a dead end thereof associated with the opposite limb, each cable being a corresponding cable with respect to the pulley on which it is reeved and an opposite cable with respect to the other pulley, each cable between the shooting string end and the pulley having a shooting portion associated with the pulley, each cable between the dead end and the pulley having a bus portion extending from the pulley to the opposite limb of the bow past the path of movement of a fletched arrow upon release of the shooting string, connected between the shooting string ends of the cables, from a drawn state thereof displaced from a relaxed state thereof, each pulley defining in the periphery thereof a first shooting groove for receiving a part of the shooting portion of the corresponding cable and a second bus groove for receiving a part of the bus portion of the corresponding cable, at least the shooting groove being defined in a plane normal to the pulley rotational axis, the grooves on each pulley being spaced from each other along the pulley rotational axis, the improvement comprising means, including the pulley and its geometry, for coupling each pulley and the associated corresponding cable portions and opposite cable dead end to the adjacent limb to prevent torsion of the limb at full draw of the shooting string and in which, as to each limb, in the said drawn state the location of application of the opposite cable dead end tension to the limb and of the locations of application of the adjacent corresponding cable bus portion and shooting portion tensions on the axle are arranged, in combination with the magnitudes of such tensions in the said drawn state and in relation to the location of the limb torsional axis, to apply no significant net torsional movement to the limb about the limb torsional axis, and in which the opposite cable dead end is effectively connected to the limb a substantial first selected distance from the limb torsional axis on one side thereof, and the corresponding cable shooting and bus portions are engaged with the pulley at the said drawn state proximate to each other at second and third selected distances from the limb torsional axis on the other side of the limb torsional axis, the first, second and third selected distances being defined in combination with the respective tension magnitudes to produce substantially balanced moments about the torsional axis at the said drawn state, and the cable bus portions extend from the pulleys to the opposite limbs along straight lines past the arrow path of movement in all strung states of the bow.
Dependencies are inferred from the claim text.