January 9, 2008
The compound bow in archery was a revolutionary invention that has changed the sport forevermore. The compound bow in archery was invented in the mid 1960s by an American engineer named Howless Wibur Allen. In 1961 he got inspired by the then launching of Hoyt Pro Medalist Bow. This bow was one of the very first to have vertical stabilizers on it, and Allen had another idea to add to it-the wheel. He harnessed the principle of the block and tackle pulley to the bow and felt (correctly) that this would enhance a bow’s performance. The mechanics of the pulley system would, he reasoned, allow a heavier weight to be drawn. After continued experimentation he found that round pulleys and cam-shaped wheels worked best and they were riding on off-set axles called “eccentrics”. The compound bow reaches its peak weight in the middle of the draw; beyond this point as the archer continues to draw back the weight of the draw is significantly reduced, allowing an average-sized archer to comfortably hold a very heavy weight. The compound bow in archery gives an amazing flat trajectory to an arrow’s flight.
It actually took several years for Allen to get anyone to manufacture his new invention, the compound bow. American laws prohibited the use of mechanical devices attached to bows. So, the compound bow could not be used for hunting nor in competitions. Allen began making his own bows, sure that they would catch on so strongly that the laws would be rewritten (and he was once again correct). However, when he was making his own compound bows he realized that he had a design flaw, as he kept on stripping the fletching off his arrows. The crossing cables in the center of the bow were interfering with the arrow’s flight. By 1967 Allen had figured out that he needed to add an extra set of “idle” wheels that got mounted at the center of each limb. These idle wheels were set at 90 degree angles to the limb-tip, and this allowed the cables to now cross to one side of the center line so that they no longer interfered with the arrows’ flight path. With more research, Allen added riser-mounted adjusters so that the archer could use different cable lengths to attain different weights. These adjusters were gear-driven and acted very much like the machine heads for tuning a guitar.
By this time, the compound bow or “Allen bow” was a superior instrument. The flatter and faster trajectory that an arrow could be given due to the increase in stored potential energy meant that now a heavy hunting arrow would be able to find its mark more often and would fly with greater speed. The lighter weight as compared to a recurve bow of the same draw weight meant that this bow was more comfortable to use, as well. However, the sport’s governing body still would have nothing to do with it.
However, the famous American archer and archery magazine editor Tom Jennings love the idea and he used his pull to get the governing body to begin reconsidering its stance. Jennings published an article titled “A Bow with a Compound Interest”. From there, the compound bow found its way into archery.
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Sunday, January 20, 2008
January 9, 2008
Posted by Rıdvan Uzuntaş ; at 8:05 AM