US2945488A - Composite bow for archers - Google Patents

Description

July 19, 1960 c. v. CRAVOTTA ETA L COMPOSITE BOW FOR ARCHERS Filed Sept. 4, 1956 INVEN ORs Cosimo V. Cravoflo- 8 James J. Crovo'lta 2,945,488 COMPOSITE BOW FOR ARCHERS Cosimo V. Cravotta and James J. Cravotta, Pittsburgh,

Pa., assignors to Cravotta Brothers, Inc., East McKeesport, Pa., a corporation of Pennsylvania Filed Sept. 4, 1956, Ser. No. 607,876

1 Claim. (Cl. 124-23) This invention relates to a composite bow for archers. More particularly, it pertains to a reinforced wooden bow which is stabilized so that deterioration or twisting out of shape is inhibited.

Past years have seen the development of numerous practices for the reinforcing of wooden bows by the employment of facing members, or backing members, or both, to counteract tensile and compressive stresses which occur in a wooden bow, as illustrated, for example, in United States Patents Nos. 2,285,031, 2,316,- 880, 2,613,660 and 2,665,678. In the case of the use of plastic for such members unreinforced by strengthening material like fibrous glass, it happens on occasion that either the bow will sag toward the string in the course of time and become let-down or that the plastic itself does not fully or adequately take care of the stresses encountered particularly along the back and face areas of the bow. And, even when longitudinal fibers of glass have been used to reinforce such members, we have discovered that despite that the bow is not always stable, particularly in the case of greater weights. Instead, trouble would arise in that such bows would sometimes warp or twist so that a plane through the bowstring of such a how when braced would not pass squarely through the bow itself including the reinforcing members, thereby rendering the bow unsuitable at least for accurate usage.

Bows made in accordance with our invention disclosed herein retain the desirable properties of wooden bows, are susceptible of being reinforced as desired on the back and/or face and, in addition, include a novel stabilizing member of strong fabric or cloth, such as glass cloth, impregnated or contained in a stiff but bendable plastic and together forming a solid strengthening member or lamination having sufiicient fabric and thickness to inhibit such warping.

Other objects and advantages will be apparent from the following description and the accompanying drawings, which are illustrative only, in which Figure 1 is a side view of a right-handed bow made in accordance with this invention, in braced but undrawn condition;

Figure 2 is a view in section taken along line II--II of Figure 1;

Figure 3 is a view in section taken along line III-III of Figure 1;

Figure 4 is a view in perspective of the center of the bow shown in Figure 1 before final shaping and wrapping of the hand grip; and

Figure 5 is a perspective view, similar to the view shown in Figure 4, of a bow constituting a modified embodiment of our invention.

Referring to Figures 1 to 4 of the drawings, a bow is shown constituting one embodiment of this invention. Therein, a wooden stave, which may be of clear straight-grained hardwood such as maple or hickory, is provided in the form of laminations 11 and 12 suitably bonded together. Lamination 11 preferably ex- States Patent 0 again by a suitable adhesive.

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tends throughout the entire length of the bow from end 13 to end 13a where nocks 15 are provided for a bowstring 14 which may be served with small stuff at nocking point 17a. As shown, the outer portions of the limbs 16 are reflex curved as shown at 17 even bow 10 is braced but undrawn as illustrated in Figure 1, although this invention is applicable to composite archery bows of other shapes and kinds which employ a wood stave.

In the bow 10, the hand grip 18 at the center of the bow may be formed in material part from a block of wood 19 having afront surface 20 and sloping end surfaces 21 making a gradual merger into the front plane of lamination 12 as shown in Figure 4. The respective laminations 12 at their inner or central ends are bonded by a suitable adhesive to the respective sloping surfaces 21, the rear surface of the portion of the laminations 12 beyond the end of block 19 being bonded to the front surface of the stave lamination 11 again by a suitable adhesive of which thereare many known to those in the art to whom this invention may be disclosed.

The back of how 10 is strengthened by a backing strip 23 bonded to the rear surface 24 of stave lamination 11 As shown, backing strip 23 comprises longitudinally extending glass fibers 25 encased and held in a relatively bendable plastic matrix 26 of a suitable material including polyester resin preformed into strip form prior to being coated with an adhesive and positioned relative to stave lamination 11 as shown in Figure 4.

Alike facing strip 27', similar to the backing strip 23 is provided for the face of bow 10 toward bowstring 14, longitudinally extending glass fibers or other suitable fibers 28 being encased and locked inthe plastic resin matrix of strip 27 which extends from the'adjacent corner of surface 20 to the corresponding end of how 10.

Preferably between such a facing strip 27 and the front of the stave member 12, We provide a stabilizing member 29 having a fabric core (indicated by crosshatching in Figure 4) and a plastic matrix of sufficient thickness from front to back to inhibit warping, such stabilizing member being bonded to the wooden stave by a suitable adhesive such as an urea glue and to the facing strip on the front side of member 29 by an epoxy-type adhesive which will adhere to glass-containing strips, although other adhesives may be equally suitable. Such members 29 extends from the center of bow 10 or other bow incorporating the teaching of this invention, substantially to the ends or tips of such bow.

In a preferred practice, the fabric in member 29 is made of glass cloth or several layers of glass cloth to occupy a substantial portion such as about 50% as desired of the whole volume of the fiat stabilizing member 29. We have found that a bendable stabilizing member may be made of a material such as that termed Formica CN 41 or FF 91, of approximately of an inch in thickness, and will normally provide satisfactory stabilizing to inhibit warping. As a consequence, bows made as taught herein resist warping or twisting so that a plane through the bowstring 14 will be normal to the transverse plane of the bow substantially from one end to the other, and, at the same time, the bow will not let-down and will fully meet the respective tensile and compressive stresses placed upon it, particularly along the back and face thereof.

After the laminations are laid up, as shown in Figure 4, with suitable adhesive on the engaging surfaces of the respective laminations and block 19, the make-up is clamped and baked for a suitable period by thermal or dielectric heating means to cure the adhesive and join the components into a unitary mass. Following such treatment, the bow is usually shaped by sanding or 3 shaping operations, including the shaping of the hand grip of which block 19 is the central item, and the limbs and ends of the bow are tillered and nocked. A leather or other pad may be placed on one side of block 19 for conformation of the hand grip which may then be wrapped with leather strip 30 and ferrules 31 of smaller leather strips or cords applied and the whole made to adhere by a suitable adhesive. In the shaping of center 18, an arrow rest may be provided or not as a bowyer desires as shown at 32 in the case of the right-hand bow 10.

A modified embodiment of our invention is illustrated in Figure 5 in a manner similar to the showing in Figure 4. In such Figure 5, parts corresponding generally in structure and functioning to parts in the embodiment shown in Figures 1 to 4, inclusive, are provided with the same reference numerals with the addition of a prime factor thereto. It will be noted that in such modification, the stave lamination 12 and the stabilizing member lamination 29' are continuous substantially from one end of the bow to the other, the hand grip block 19 having its rear surface bonded to the front face of the center of the stabilizing member 29. Other lamination arrangements may be made within the purview of this invention and the form of the stabilizing member may be varied. Thus, 21 facing strip such as facing strip 27 and a stabilizing member such as member 29 may be made as a single lamination at one and the same time, or the stabilizing member 29 may be used to serve both as a stabilizing member and as a facing strip, particularly when glass cloth fabric is utilized as the core member therein with sufficient strands in the warp to withstand the longitudinal stresses and suflicient strands in. the weft or woof to withstand and resist bending or twisting stresses as a part of the structure of such stabilizing member.

Various other modifications may be made without departing from the spirit of our invention or the scope of the appended claim.

We claim:

A composite bow for archers, comprising, in combination, a transversely laminated wooden stave, said laminations being bonded to each other, a backing strip extending from end to end of said bow bonded to the adjoining lamination, a center block bonded to the center of said stave, the ends of said block having a graduated slope toward respective ends of said stave, a stabilizing member in strip form bonded to the front of said stave and extending substantially along the length of said bow and from side to side thereof, said stabilizing member comprising glass cloth embodied in a bendable plastic, said glass cloth having relatively longitudinal and transverse fibers in interengaging relation, said stabilizing member further having appreciable thickness sufficient to resist deformation due to twisting tendencies in other components of said bow, and 21 facing strip bonded to said stabilizing member and extending from end to end of said bow, said backing and facing strips comprising longitudinally extending glass fibers encased in bendable plastic, whereby said bow is protected against stress and deterioration including warping.

References Cited in the file of this patent UNITED STATES PATENTS 2,602,766 Francis July 8, 1952 2,695,178 Rheinfrank Nov. 23, 1954 2,749,643 Scott June 12, 1956 2,815,015 De Giacomo Dec. 3, 1957 FOREIGN PATENTS 627,255 Great Britain Aug. 4, 1949 716,040 Great Britain Sept. 29, 1954 OTHER REFERENCES Article by Noecker, on pages 5 and 6 of the American Bowman-Review of January 1946.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,945,488

July 19, 1960 Cosimo V. Cravotta et al.

that error appears in the of the above numbered patent requiring correction and that the said Letters Patent should read as correct Column 2,

line 5, before "bow" for "extends" insert when line 46 read extend Signed and sealed this 20th day of December 1960.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSUN Attesting Officer Commissioner of Patents

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