Mechanical guns and projectors – Spring – Bow
Reexamination Certificate
2000-11-22
2002-10-29
Ricci, John A. (Department: 3712)
Mechanical guns and projectors
Spring
Bow
Reexamination Certificate
active
06470870
ABSTRACT:
PRIOR ART REFERENCES
12/1969
Allen
3,486,495
7/1973
Nishioka
3,744,473
10/1974
Ikeya
3,844,268
11/1974
Eicholtz
3,850,156
2/1975
Helmick
3,865,095
10/1976
Islas
3,981,290
2/1976
Nishioka
3,989,026
11/1976
Groves
3,993,039
2/1977
Jennings
4,005,696
12/1975
Trotter
3,923,035
8/1978
Shepley
4,103,667
1/1980
Caldwell
4,188,345
10/1980
Jones
4,227,509
9/1981
Islas
4,287,867
7/1982
Darlington
4,338,910
12/1982
Nishioka
4,365,611
1/1983
Simonds
4,368,718
8/1983
Simonds
4,401,097
3/1984
Ricord
4,457,288
4/1984
Simonds
4,461,267
8/1984
Nishioka
4,465,054
7/1985
Simo
4,530,342
3/1987
Powers
4,649,890
5/1987
Humphrey
4,667,649
6/1987
Schaar
4,669,445
8/1987
Larson
4,686,955
3/1989
Felice et.al
4,819,608
10/1990
Pickering et.al.
4,957,094
2/1998
Allshouse et al
5,718,212
7/1999
Allshouse et al
5,921,227
BACKGROUND OF THE INVENTION—INTRODUCTION
In 1969 Holless W. Allen received a patent (U.S. Pat. No. 3,486,495) on the first successfully marketed version of an archers bow using mechanical advantage gained by affixing a pulley system to the ends of the bows limbs. Prior to Allen's bow, other mechanically advantaged bow inventions had centered more on employing springs or other mechanical means to accelerate the two bow limbs, with each limb being mounted over a pivot which incorporated a rotating axle, similar to simple catapults. Allen's invention accomplished the desired adaptation of mechanical advantage in a manner that both:
1. allowed the archer to flex (bend) limbs that were stiffer than he or she could have bent without the aid of the pulley system, and
2. provided that the amount of drawing force required to hold the bow in a fully drawn position was less than the amount of drawing force needed to reach peak energy storage in the “system” during the process of drawing the bow back to full draw from an “at rest” position. This was accomplished by placing the pulleys axle hole in an eccentric position.
The stated objective of the Allen Patent application providing that the invention would also allow the use of less stiff (and therefore smaller diameter and lighter for a given length and type of material) arrows, thereby further dramatically increasing arrow velocity, did not initially materialize effectively in practice due to other elements of the invention that were later found to offset this hoped for effect, and due to reduced target penetration that was found to occur when using the lightest arrows possible from the new style bow. Modest (10-20 feet per second) increases over the older recurve bow styles of the same draw length and draw weight occurred, due to the difference in the manner whereby compound bows released their stored energy into accelerating the arrow out of the bow (higher amount of energy transmitted for a somewhat longer period of time overall).
Allen's “compound” bow, as all such mechanically advantaged bows thereafter came to be known, employed a compound style pulley system wherein one end of a cable was pre-wrapped around one groove of a twin grooved, eccentrically mounted pulley suspended from an axle assembly that was, in turn, mounted near the outmost end of one of the bows two flexible cantilever type limbs. Sufficient length of cable, in addition to that needed to surround the pulley groove on this side of the pulley (primary pulley side), was provided for later attaching a bowstring to this end of the cable during the assembly of the bow.
The opposite end of the same cable passed diagonally through the pulley emerging from the opposite side (secondary side) of the pulley and traveled, without first being wrapped around the second groove cut in the secondary side of the pulley, from the point of emergence from it's groove to a point where it was fixedly attached directly to the limb on the other end of the bow (in the first “two-pulley” models introduced in the market, however, circa 1974, the tieoff point for the tensioning actuators was moved to a point on the axle that was supporting the eccentric compound pulley mounted on the other end of the bow).
As the archer drew the bow back to full draw, the cable that was pre-wrapped around the groove comprising the outside circumference of the primary side of the compound pulley was unrolled in a manner that effectively caused the bows draw length to lengthen and concurrently applied leverage to the opposite (secondary) side of the pulley which simultaneously wrapped up cable into the groove comprising the circumference of that pulley side, exerting pressure on the point where the end of the cable exiting the secondary side of the pulley was tied off on (fixedly connected to) the limb on the other end of the bow, thus causing the limb mounted at the opposite end of the bows riser section to be pulled in the direction of the pulley that was exerting the pulling force.
When the bowstring was released, after the bow had been drawn back to a fully drawn state (“full draw”), the limbs returned to their original position, causing the cables now wrapped around the groove surrounding the circumference of the secondary side of each pulley to now unroll from the groove that they had been wrapped around, and the (then unwrapped) cable in the pulley groove surrounding the circumference of the primary side of each pulley to then simultaneously once again become wrapped around it's groove as was the case prior to beginning the drawing of the bow. Thus, the pulley on the top limb of the bow was rotated back to it's original, pre-drawn position by pressure exerted from the energy stored in the limb on the bottom of the bow, and the pulley on the bottom limb of the bow was rotated back to it's original pre-drawn position by pressure exerted from the energy stored in the limb mounted on the top end of the bow.
Allen's invention called for each bow limb to incorporate such a “compound” pulley system with each such pulley providing mechanical leverage in a manner that actually bent or flexed the limb on the opposite end of the bow during the drawing of the bow, and for the energy then stored in each limb on the bow to then provide the force necessary to rotate the opposite pulley back to it's original position when the bowstring was released, after drawing the bow back to full draw, all in a necessarily very closely “bisynchronized” manner so as to provide for also accelerating the arrow in a manner that did not cause it to vary from the direction of aim as it was propelled forward from the bow.
The “bisynchronous” nature of the limb/pulley arrangement employed in Allen's invention required that the actuators (cables) that operated the pulleys mounted on each bow limb intersect one another or “cross over” at some point intermediate to the bowstring and the frontmost point on the bow.
Two cables, normally constructed of steel aircraft cable (usually coated with nylon, one for each pulley) intersecting each other at a point between the bowstring and the handle or grip section of the bow, were most commonly employed as pulley actuators to roll and unroll the pulleys themselves, with a separate “bowstring section” made of lighter in weight (normally dacron) material being used to connect the free ends of the cable end that started out pre-wrapped around each pulley.
Since 1969, many different variations of the wire rope/bowstring “stringing” approaches, designed to provide a system of “working” actuators for the bisynchronous limb/pulley arrangement specified in Allen's invention, have found their way into the marketplace, including combinations using all wire rope in a “continuous loop” and similar arrangements made out of newer materials such as aramid and polyolefin fibers, and versions that provided for the cables to “cross over” in recessed grooves reserved for that purpose in the handle “riser” section of the bow.
Allen's invention was a commercial success because it more effectively addressed several important needs of the majority of archers than had prior art versions of archers bows. The market for archers bows consists, in the very great majority (over 95% of
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