US 3015327 A
Description (OCR text may contain errors)
Jan. 2, 1962 J. F. LIGHTCAP ARCHERY BOWS Filed Sept. 4, 1959 JNVEN TOR. JosEPH F. LIGHTCAP United States Patent O 3,015,327 ARCHERY BOWS Joseph F. Lightcap, 3108 Ave. I, Brooklyn 10, N.Y. Filed Sept. 4, 1959, Ser. No.`838,093 7 Claims. (Cl. 124-23) This invention relates to archery bows. More particularly it relates to a novel and improved construction for such bows.
As is well known to those4 skilled in theart of bow making, the back of a bow is subjected to tension forces and the front of the bow, i.e., the side nearest to the string, is subjected to compression forces when the bow is exed. In the case of bows made of wood, the side under tension tends to fail due to the breaking out of small slivers which is eventually rfollowed by splitting. Because of this the best wooden bows were made of yew since its heartwood is strong in compression while the lsapwood is resilient and strong in tension. Thus when a bow was formed out of yew with the sapwood used for the back and the heartwood for the `front or belly of the bow, the characteristics of the wood were matched to the conditions to be met in the bow.' Moreover, the back of the bow was made `to exactly follow the grain of the wood, leaving the shaping, when needed, to be done in the belly of the bow exclusively. This, in addition to the cost of yew, meant that bows made of yew were comparatively expensive. Bows -made of other wood while less expensive to manufacture were more prone to breakage.
Recognition of the fact that bows under stress could be analyzed according to beam theory has led to many attempts to improve the strength of bows and render them less susceptible to mechanical failure. For example, the prior art teaches that bows were backed with materials that had a high .tensile strength, such as silk bers and glass bers. Bow limbs also were made of laminations of different types of wood having differing properties so that the composite limbs would be suited to the forces that would be encountered when the bow was flexed. While the structural features of a bow were thus being improved, other desirable bow characteristics were being sacrificed. For example, bows became heavier and more fatiguing when used by the archer. Moreover, the potential casting ability of bows was inhibited.
Therefore, it is an object of this invention to provide a bow of novel construction which will be structurally sound, light in weight and efficient as a bow.
In carrying out the invention there is provided a bow having a honeycomb core and a backing strip of glass ber fabric. The belly of the bow may also be faced with a strip of glass ber fabric.
An advantage of a bow made according to my invention is that the use of wood has been eliminated so that varying bow characteristics due to temperature and humidity changes have been obviated.
A further advantage achieved by eliminating the use of wood is that bows of uniform characteristics can be manufactured since the bow is made of products which can be readily controlled to provide uniform structural characteristics rather than of a natural product such as, wood, which varies in structural characteristics from lot to lot.
A still further advantage of my bow construction is that it provides a -very light weight bow which is highly resilient.
Other features and advantages of my invention may be gained from the specification of a preferred embodiment thereof which follows.
In the drawings:
FIGURE 1 is a side elevation of a strung but unflexed bow embodying the present invention;
, the honeycomb core 15 is cut to the same size.
FIGURE 2 is an enlarged fragmental longitudinal section of the bow taken at the handle part thereof;
FIGURE 3 is a sectional view taken along line 3 3 of Referring to the drawings, an archery bow represented Y generally by the reference numeral 10 comprises a centrai handle portion 11 with two exible limbs 12 and 1'3 extending therefrom and joined by a string 14..
The body of the bow is formed of a central honeycomb core 15 which is sandwiched between strips of scrim cloth 16 and 17 and a glass ber backing layer 20. Another layer of glass ber 21 is used for the facing of the bow. In the central portion of the bow a handle piece 22, suitably shaped is inserted between the facing layer 21 and lthe strip of scrim cloth 17.
While the scrim cloth can be eliminated and the glas ber layers adhered directly to the honeycomb core, it is As in the case of the scrim cloth, the side rail members may be omitted from the construction since they do not contribute to the improvement of the bow characteristics as such. If they Vare omitted, the edges of the bow could,
be made smooth by lling in the sides of the honeycomb with an adhesive or other plastic which can then be sanded down. As noted the provision of the side rail members is to improve the appearance of the bow.
The honeycomb core which I have found satisfactory is one made of aluminum having the conventional hexagonal openings as illustrated in the drawings. Of course, honeycomb cores of other materials maybe employed provided they have the requisite structural characteristics. In the same way, the openings in the core need not be of hexagonal eros-section, but may be circular or polygonally cross-sectioned. Moreover, the openings need not be perpendicular to the axis of the bow. Furthermore, the openings of the honeycomb core may be lled with a light weight material, such as a plastic, to provide a solid core which is light in weight.
In fabricating the bow, the glass ber layers 20 and 21 are cut to size and rough sanded on one side. In one construction, the bow is fabricated in one piece, i.e. with the honeycomb core running from tip to tip of the bow, rather than as two limbs joined to a central handle portion. The scrim cloth strips are cut to sizes corresponding to that of the glass ber layers. Similarly, The sanded sides of the glass ber layers and the scrim cloth strips are then spread with an epoxy adhesive and placed against the honeycomb ycore as indicated in the longitudinal sectional View. A handle member 22 which has been suitably shaped and tapered is inserted between the strip of scrim cloth 17 and the glass fiber facing 21. The assembly is then clamped in a laminating form which conforms to the desired unstrung prole of the bow. The entire assembly is then cured in an oven. ln fabricating the bow, a clamping pressure of fifty pounds per square inch (50 p.s.i.) and a curing operation of one hundred and forty degrees Fahrenheit F.) for three hours has been found satisfactory. After the bow has been cured it is removed from the laminating form and the tillering of the -bow then takes place. During tillering, material may be removed from either limb of the bow until the same amount of bending occurs in each limb. When the bow has thus been prepared the side rails may be secured thereto after which the bow is fine sanded and lacquered.
bow constructed according to the foregoing description has been made and found eminently successful in use. TheV glass -fiber layerswere forty thousandths of an inch (0.040)V thick and one and one half-inches (l1/2) wide whilethe 4honeycomb core was one eighth of an inch thick and one and one half inches (l1/2") wide.
While it was noted that one constructional form of the bow employed a honeycomb core running fromV tip Ito tip of the bow, `the bow could be Ifabricated with a static handle portion andthe honeycomb core extending only in the limb portions of the bow. In fact, this latter construction is favored when an improved pistol type handle is used on the bow. Here the honeycomb would extend from the tip of a limb and be feathered into the shaped handle, preferably on the facing side of the handle. In
the same manner the glass ber facing layer would be in Y l. An archery bowcomprising avcore formed ofV an .l
inorganic honeycomb member, a layer ,of high compresa sive strength material secured tothe face of said honeycomb member, and a layer of high tensile strength material secured to the back of said honeycomb member.
2. An archerybow having a handle section and a pair `of limbs each of which extends from an end of the handle section to form a bow stave, wherein each limb comprises a core formed of anV inorganic honeycomb member, a
layer of high`compressive strength material secured'to the face ofsaid honeycomb member, and a lawyerv of high 4 p tensile strength vmaterial secured to the back of said honeycomb material. k
3. An archery bow comprising a -core and `formed of an aluminum honeycomb member, a glass ber layer secured to the face of said honeycomb member, and a glass fiber layer secured to the back of Vsaid honeycomb member.
4. An archery bow having a handle section and a pair of limbs each of which extends from an end of the handle section to form a bow stave, lwhereinV each limb comprises a core Vformed of an Valuminum honeycomb memlber, a glass ber layersecured to the face of said honeycomb member, and a glass ber layer secured to the back of said honeycomb member.
5. An archery bow comprising a core formed of an Y compressive strength material, an intermediate layer of scrim cloth between said facing layer and said honeycomb member, a backing layer of high tensile strength material and another intermediate layer of -scrim cloth betweenV said backing layer and said honeycomb member.
. References Cited in the le of this patentv UNITED STATES PATENTS 2,053,135 Dalton Sept. 1, 1936 2,609,068 Pajak Sept. 2, 1952 2,665,678 Bear.v lan. 12, 1954 2,815,015 De Giacomo Dec. 3, 1957 2,818,057V Meyer et al Dec. 31, 1957 2,851,133 Steele Sept. 9, 1958 2,894,503 Pierson et al V Iu1y 14, 1959