This invention relates generally to the art of archery and, more specifically, to the art of take-down bows using laminated-limbs.
Bows have been used in archery for centuries, and many innovations have been proposed to increase their performance. One need in the art has been for portability. The bow is quite long; and, therefore, there have been repeated attempts to design take-down bows that were more portable than the monolithic structure, but which were as fast-shooting and accurate.
One example of such an attempt is seen in U.S. Pat. No. 2,000,832, issued to Fisher, which disclosed a bow made from metal. The limbs are inserted into a handle structure of seamless tube steel, open at both ends to hold the shanks of the metal limbs. However, the Fisher structure has a number of problems, and it has not been accepted by archers. For example, the handle of Fisher is open on the top end, for receiving the upper limb, thus resulting in dirt, water, and other foreign materials being enabled to enter the opening. Those foreign materials scratch, gall, and corrode the socket, thus causing a non-uniform fit between the limb and handle. Further, the use of metal limbs causes the bow to be very heavy. Further still, having separate limbs and handle results in two joints, each of which must be exactly aligned if the bow is to shoot the same each time it is put together; and, there are three pieces that must be handled in assembly.
Another example of an attempt to make a take-down bow is seen in U.S. Pat. No. 1,709,630, issued to Rounsevelle. Unlike Fisher, Rounsevelle had a two-piece structure. However, Rounsevelle faced the same fouled joint and alignment problems of Fisher. In an attempt to address this problem, Rounsevelle provided a tapered two-sleeve fastener, each sleeve being attached permanently to one limb. However, each sleeve is tubular and the female sleeve is attached to the lower limb. Such an attachment has numerous disadvantages, among which is the tendency for the upward-pointing female sleeve to collect water, dirt, snow, etc. Further, the sleeve placement and tapering weakens the bow, limiting the size of the sight-window that can be cut in the upper limb. Further still, Rounsevelle does not provide for a close-tolerance fit to increase repeatability of the way in which the bow would shoot after being taken down and reassembled. Apparently, Rounsevelle did not recognize the need. Nor does Rounsevelle provide any way in which the metal surfaces of the sleeves can be protected from galling, corrosion, or other deterioration. Rounsevelle's bow, also, has not been accepted by archers.
Yet another attempt to make an acceptable take-down bow is seen in U.S. Pat. No. 2,073,418, issued to Gille, et al. Gille shows a metal-limbed bow with a "D-shaped" sleeve structure for aligning the metal-tube limbs; however, Gille has many of the previously mentioned problems. For example, due to the tubular nature of the limbs, there can be no provision for a deeply cut sight-window in the upper limb; and, the upper limb is inserted into the handle, thus creating an upward-pointing female sleeve. Further, Gille fails to disclose any way to prevent galling, corrosion, wear, etc. of the joints. Further still, Gille shows that the prior art intentionally placed the female sleeve on the lower limb of the take-down bows, in order to have the wider portion of the bow in the handle, thus allowing the top of the female sleeve to be used as an arrow rest. Gille's bow has not been accepted by archers.
Another take-down bow is seen in Australia Patent No. 135,941, issued to Brewer, which discloses yet another socket arrangement in which the female sleeve is mounted on the lower limb, causing the same problems discussed above. Further, Brewer teaches that the metallic socket members should be pinched or clamped to the wood limbs. Such an arrangement destroys the limbs due to compression of the soft wood by the hard metal, and has not been accepted.
Another metal-limbed, take-down bow is seen in U.S. Pat. No. 1,810,335, issued to Barnhart, which again teaches that non-metal bow limbs are undesirable. Also, Barnhart fails to address the above-noted problems; and, like the previously-mentioned bows, has not been accepted.
One of the more modern improvements in archery has been the advent of laminated-limbs. Such laminated-limbs allow for more uniformity in manufacture, better control, and faster shooting bows. However, the laminated-limbs suffer from the problem that they are soft. Also, they are as prone to damage in take-down bows as were wood limbs. Further, the laminated-limbs are of a different shape. The older wood and metal-tubed bows were rounded in the limbs, allowing for the use of tube-like sleeves for the joints; while, in modern laminated bows, the limbs are flattened, resulting in the necessity to fit a rectangular peg (the laminated-limb) in a substantially round hole (the tube) if the tubular sleeve of old are used. The art did not see such a solution as practical, and opted for rectangular-rectangular limb-to-riser connection means, using a metal-riser and two, separate laminated-limbs, as discussed below.
The advent of the metal-riser, in which the grip, arrow rest, and sight-window were incorporated, allowed the art to make the only take-down bows that, to date, have met with acceptance. Those metal-risers allowed for insertion of separate laminated upper and lower limbs, thus creating a three-piece, take-down bow. Since the riser was metal, and therefore strong, a deep sight-window could be cut therein, allowing the bow to cast the arrow more closely along the plane of the bow--that is, the plane in which the limbs tend to force the string. Such alignment improves the speed and accuracy of the bow. Further, the ends of the riser, above the sight-window and below the grip, could be shaped to conform to the rectangular shape of modern laminated-limbs.
Some three-piece, metal-riser take-downs, such as that made by Bear Archery, had rectangular pockets at each end of the riser into which the laminated-limbs were loosely inserted. Tension on the string forced each limb to stay in the riser. The first shot with such a bow was usually accompanied with a load gun-shot sound as the limbs "seated." The first shot was not considered to be accurate, due to the lack of seating. Some archers would half-draw the bow and release the string to seat the limbs before the first shot. The practice, understandably, was not considered to be conducive to long life for the bow. Further, in high draw-weight bows, the limbs tended to creak during the draw. Further, when the bow was shot, the limbs rattled in the pockets, resulting in loud, noisy bows----not well suited to hunting, where many animals react fast enough to move out of the way if they hear either the draw, or even the shot.
Other bow makers, also attempting to provide the portability of a take-down bow, still using metal-risers and separate upper and lower laminated-limbs, provided channels into which the butt of each limb was inserted. A bolt was inserted through the laminated-limb and into a support shelf located on the shooter's side of the riser. Thus, as the bow was drawn, the laminated-limb pressed against the shelf on the shooter's side of the riser. The channel wall on the target side of the riser held the limb in place. The bolt provided stability. Such a design was, effectively, the only design used by olympic-style (FITA) archers during the last three decades. Examples of such bows include the Hoyt (now Easton) TD-2 and TD-3, and the Yamaha bows that competed therewith, as will be understood by those of skill in the art. These bows included the same seating and noise problems associated with other three-piece, metal-riser, take-down bows.
An additional problem with the three-piece, metal-riser bows was the short limbs. Because the riser was stiff, no part of the riser could be used to impart energy to the arrow. All of the mechanical energy had to be stored in the relatively short laminated-limbs. The result was that take-down bows tended to shoot slowly.
The need for speed of arrow flight led to the development of what is now known as the compound bow. Such a bow is known to those of skill in the art as a cam-operated, cable bow, using a metal-riser and very short, but very thick, laminated-limbs. The overall length of such a bow is substantially shorter than the traditional one-piece bow, allowing somewhat for the portability desired in a take-down bow, and the compound shoots faster for the same draw weight in a three-piece take-down. However, it is fairly complex and cannot be easily unstrung and restrung with consistent accuracy.
Therefore, there is, and has long been, a need for a two-piece, take-down bow with shock absorbing qualities that can be made from modern, laminated-limbs and be assembled accurately, time after time. Also, there is a need for the two-piece, take-down bow to provide for a close tolerance fit, with resistance to galling, corrosion, fouled joints, and the like, while still providing a deeply cut sight-window, ease of set-up with repeatable performance between set-ups, and accuracy.
USPTO Backgrounds
USPTO Backgrounds