The book's dustjacket is illustrated by bird artist David Nurney - the front cover shows a Common Kingfisher (with a map of its distribution), while a European Bee-eater is depicted on ...
In a compound archery bow having composite bowstring and take-up string cam pulleys carried by the tip portions of bow limbs extending oppositely substantially symmetrically from a handle with the bowstring connecting the composite cam pulleys and take-up strings extending from each composite pulley to the opposite bow limb, each composite cam pulley is composed of a generally elliptical bowstring pulley section having a major axis passing through its portions of substantially greatest length and a generally elliptical take-up string pulley section having a major axis passing through its portion of substantially greatest length, which pulley sections are integrated in parallel side-by-side relationship with planes containing their major axes substantially perpendicularly intersecting. The effective bowstring lever arm of the bowstring pulley section is small and substantially constant during increase of the draw force to at least 90 percent of the maximum draw force while the bowstring nocking point is displaced less than 40 percent of the total displacement during draw and the bowstring lever arm then increases substantially linearly while the draw force remains at a substantially constant maximum value over at least a third of the total bowstring nocking point displacement during draw of the bowstring. The ratio of bowstring draw arm to take-up string draw arm is substantially constant during the draw force increasing phase of the draw.
Compound Bow And Eccentric Wheel Assemblies Therefor
A compound bow includes a handle portion and appended limbs, eccentric wheel assemblies mounted to each bow limb, and a cable attached at its ends to the bow limbs and extending over the wheel assemblies. Each wheel assembly includes a bowstring wheel having a peripheral groove, a first take-up wheel having a peripheral groove, and a central passageway communicating between the grooves to permit attachment of the bow cable. A second take-up wheel is secured to the bowstring wheel and includes a peripheral groove which is aligned with the groove of the first take-up wheel. The take-up wheels are configured such that the cable is not received in the groove of the second take-up wheel when the bow is in the relaxed condition, but is so received when the bowstring is drawn. The draw characteristics of the bow are therefore changeable by substituting various shapes of the second take-up wheel, and such substitution may be readily accomplished without requiring that the bow be dismantled or unstrung.
Composite bowstring and take-up string cam pulleys are carried by the tip portions of a compound archery bow limbs extending oppositely substantially symmetrically from a handle with the bowstring connecting the composite cam pulleys and take-up strings extending from each composite pulley to the opposite bow limb. Each composite cam pulley is composed of a generally elliptical bowstring pulley section having a major axis passing through its portions of substantially greatest length and a generally elliptical take-up string pulley section having a major axis passing through its portion of substantially greatest length, which pulley sections are integrated in parallel side by side relationship with planes containing their major axes substantially perpendicularly intersecting. The effective bowstring lever arm of the bowstring pulley section is small and substantially constant during increase of the draw force to at least 90 percent of the maximum draw force while the bowstring nocking point is displaced less than 40 percent of the total displacement during draw and the bowstring lever arm then increases substantially linearly while the draw force remains at a substantially constant maximum value over at least a third of the total bowstring nocking point displacement during draw of the bowstring. The ratio of bowstring draw arm to take-up string draw arm is substantially constant during the draw force increasing phase of the draw.
David Nurney 1968 graduate of Lincoln-Sudbury Regional High School in Sudbury, MA is on Classmates.com. See pictures, plan your class reunion and get caught up with David and other ...