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Jennings Compound Bow, Inc.

Joseph M Caldwell

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.

Compound archery bow

A limb for a compound archery bow has an inboard end and an outboard end at opposite sides of an elongate axis. The inboard end is adapted to be secured to a handle riser of the bow. The outboard end is forked to define an outward opening crotch for accomodating a pulley. The limb is split along its elongate axis from the inboard end of the crotch for a substantial portion of the length of the limb toward the mounting at the limb inboard end to divide the limb into two limb portions on opposite sides of the elongate axis. Cooperation is provided at at least one location along the limb for holding together the limb portions sufficiently so that, upon application of a limb flexing force to a pulley axle at the outboard limb end, the limb portions flex essentially as though the limb were unsplit along its length.

Axially-split archery bow limb

Pulley for compound archery bow

Pulley for compound archery bows

An archer'shooting bow comprises a pair of elongate resilient limbs, each disposed at a respective end of an elongate rigid handle riser assembly which has a central handle portion. The limbs have outer tips at the opposite ends of the bow. A bowstring is coupled between the outer limb tips adjacent the rear face of the handle riser assembly. The bowstring has a nocking point adapted to be drawn from a rest position to a drawn limb-flexing position on application of drawing force thereto. A mounting device connects each limb only at a location intermediate its length to the respective end of the handle riser assembly for hinging motion of the limb relative to the assembly about an axis disposed substantially perpendicular to the plane in which the bowstring moves in being drawn from its rest to its drawn position. The geometries of the mountings of the limbs to the assembly are such that each limb has an inner tip adjacent a front face of the handle riser assembly proximate the handle portion. A tether device is connected between each limb inner tip and the handle riser assembly for constraining the inner tip from movement away from the assembly in response to application of drawing force to the bowstring. As the bow is drawn, each limb flexes on both sides of its point of hinging connection to the handle riser assembly in a manner analogous to a simply supported beam loaded by a concentrated load at said location. A bow having only one such limb and tether arrangement is also described.

Archer's bow with intermediately pivoted limbs

A compound bow having a center handle portion, upper and lower limbs having inner ends connected to the handle portion, and upper and lower draw pulleys mounted on the free outer ends of the upper and lower limbs. Each of the draw pulleys has a peripheral portion, a central portion, and first and second spaced grooves in the peripheral portion. A passage in each draw pulley leads through its central portion and connects the first and second grooves. Each pulley has an inner surface portion and an outer surface portion on the peripheral portion with the inner surface portion facing the bow and the outer surface portion being directed away from the bow when the bow is in its rest position. A pivotal mounting is provided for each pulley with the pulleys being eccentrically positioned on the mountings for rotational movement during draw of the bow with the bowstring supported by the pulleys. Rotational movement of the pulleys increases the effective length of each of the bow limbs. Due to the structure and positioning of the pulleys and the manner in which the pulleys are supported by draw cables, the force required to draw the bow increases rapidly when the bow reaches its fully drawn position so that it is virtually impossible to overdraw the bow.

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Tujunga, CA, United States of America

Joseph M Caldwell