US2689559A

US2689559A - Archery bow

Info

Publication number: US2689559A
Application number: US287835A
Authority: US
Inventors: Leonard S Meyer
Original assignee: Parallel Plastics Co
Current assignee: Parallel Plastics Co
Priority date: 1952-05-15
Filing date: 1952-05-15
Publication date: 1954-09-21
Anticipated expiration: 1971-09-21

Description

Sept. 21, 1954 Filed lay 15. 1

L. S. MEYER ARCHERY B07! mmlllllllllllm 3 Sheets-Sheet 1 ELQ INVENTOR. Q) LEONARD 8. ME YER BY i a ATTS. Y

P 21, 1954 L. s. MEYER 2,689,559

ARCHERY Bow Filed May 15, 1952 3 Sheets-Sheet 2 INVHVTOR. LEONARD .5. ME YEA? p 1954 s. MEYER 2,689,559

ARCHERY Bow Filed lay 15, 1952 s Shpts-Shaat s MATERIAL uvmvrox LEONARD 5. MEYER ATI'S Patented Sept. 21, 1954 ARCHERY BOW Leonard S. Meyer, Newark, Ohio, assignor to Parallel Plastics 00., Newark, Ohio, a partnership consisting of Leonard S. Meyer and George A. Shira Application May 15, 1952, Serial No. 287,835

9 Claims.

My invention relates to an archery bow. It has to do, more particularly, with an archery bow which is molded as a single piece from fiberreinforced plastic.

Archery bowshave been formed in the past from a number of different materials such as wood, metal, etc. and these materials have also been used in laminated form in bows. It is very expensive and very difiicult to form a proper bow from metal due to the inherent difficulties in fabricating metal. It is almost impossible to cast a good bow from metal and, consequently, good bows from metal must be formed by rolling or forging operations. The fatigue properties of metal, such as spring steel, are not too good. Oh the other hand, although it is fairly simple to fashion a bow from Wood, such material has certain undesirable properties for a bow. It does not have suflicient elasticity; it is not sufficiently dense and, therefore, is easily marred or cut and has relatively poor fatigue strength (creep at high stress) and its properties vary with temperature changes which variation is undesirable in a bow.

I have found that an ideal material for forming an archery bow is fiber-reinforced plastic. I prefer to use a thermosetting resin and glass fibers or glass yarn. The bow can be molded from this material as a single unit. To obtain the most desirableresults, the glass fibers are arranged parallel to one another and parallel to the longitudinal axis of the bow. In using a bow it is understood that the face of the bow (the side towards the archer) is in compression and the back is in tension. To compensate for this difference in forces, I use different types of resin at the face and back of the bow which are selected to more adequately resist the respective forces to which the face and back of the bow are subjected. Furthermore, the relative areas of the face and back of the bow are different to compensate for the difference in forces to which the face and back are, respectively, subjected. The design of each limb of the bow is such that vibration or shock waves are dampened when the bow is used and this is especially important with this reinforced resin material which has a high density. The glass fiber-reinforced plastic which I use in the bow does have a high density (usually 1.75) which is higher than any of the usual materials except metals which makes it extremely durable and prevents marring or cutting of the bow; it has a high strength-weight ratio; a high degree of elasticity; exceptionally good fatigue properties; exceptionally good and substantially uniform properties over a wide temperature range; and good color properties, the color extending completely through the material.

The preferred embodiment of my invention is illustrated in the accompanying drawings where- 1n: Figure 1 is a side elevational view of a bow made according to my invention.

Figure 2 is a face view of the bow of Figure 1 taken substantially along line 2-2 of Figure 1.

Figure 3 is a back view of the bow taken substantially along line 3-3 of Figure 1.

Figure 4 is an enlarged side view of the center section of the bow showing part of the hand grip and the associated arrow rest.

Figure 5 is a back view of the structure of Figure 4.

Figure 6 is a View similar to Figure l but showing the string in place on the bow.

Figure 7 is a face view of the bow taken along line 'll of Figure 6.

Figure 8 is a back view of the bow taken on line 8-8 of Figure 7.

Figure 9 is an enlarged view of one of the string nooks and brush nooks on the end of the bow.

Figure 10 is a diagram showing the arrangement of the different types of resin in the bow.

Figure 11 is a transverse section taken substantially along line ll-Ii of Figure 5.

Figure 12 is an enlarged transverse section taken along line 12-12 of Figure 8.

The bow of my invention is formed in the shape shown in Figure 1. It is molded in this shape in a mold under pressure. The materials used, as indicated, are reinforcing fibers and resin. The fibers are preferably, of glass and are disposed longitudinally of the bow substantially parallel with the longitudinal axis thereof. The arrangement of the glass fibers embedded in the resin is illustrated in Figure 11. The resin which I preferably use is of the polyester type.

It will be noted from Figures 1 to 3 that the bow is molded with the central heavy center handle section 20 and with the two oppositely extending limbs 2| and 2|a.

The limbs 2| and Zia are each of modified S shape so as to dampen vibration and shock waves when the bow is used, it being understood that each limb functions as a cantilever beam and the more complicated the shape of the beam, the less vibration there will be transmitted to the handle section 20. This is especially important with the high density material of which my bow is composed, the density being at least 1.75. The bow is of the shape shown in Figure 1 before the string is applied thereto. At the outer end of each limb 2| and 21a of the bow there is formed an integral string and brush nock 22 which functions in the usual way. This nook is shown best in Figure 9, being in the form of a bulge which is formed on the face side of the limb of the extreme-end thereof and having-a straight string channel or grooveZB extending the length thereof and merging with a Y-shaped channel at the extreme end thereof where the string loop is to fit over the retaining projection 24.

The central handle section 28 is of heavy rigid construction but is provided with transverse holes 25 to reduce weight. This section is shaped to fit the hand and may be wound with suitable tape or material 26 for a hand grip. Directly above the hand grip there are formed on the. right .and left hand sides of the bow, the ledges or shoulders N which form arrow supports so that the bow can be used by a right or lefthanded archer. It will be noted from Figures 2 and 3 that the sidesZB of each limb 2i and Bio of the how are straight and are not parallel but converge towards the outer end thereof. As the sides of each limb 2i and Zia approach the central section 2d, they converge as indicated at 292. Directly above the arrow rests 2?, the converging sides of the upper limb continue as straight'and parallel surfaces as indicated at so to provide substantially flat guidesurfaoes with which the sides of arrows may contact when they are resting on the ledges 2?. The sides of the lower limb 21a are exactly the same as those of the upper limb 2! except that the straight arrow guide surfaces so are not provided below the hand grip 25.

Before flexing the bow to apply the string, it is in the shape shown in Figure l; at this time the face side of the upper limb includes the continuous convex curve 33' which joins with the reverse or concave curve 32 which terminates at a shoulder 33 directly above the hand grip it, the shoulder aiding in preventing slipping of the bow downwardly through the hand. The face side of the lower limb Zia is similarly formed with the convex curve filo which merges with the concurve 32s that merges with the convexly curved surface of the hand grip The back of the limb if is provided with a continuous convex curve 35 which will be parallel with the curve 3i and which will merge with a reverse curve that merges into-the hand grip 26. It will be noted that since the curves 3! and are substantially parallel, the other part of the limb '2! is fairly thin and, therefore, very flexible. On the other hand, the curves 32 and 3?} are not parallel but 'diver-ge'so that the thickness of the limb increases towards the hand grip it. However, there isa gradual increase in thickness so that there is a gradual decrease in flexibility to the rigid handle section. The back sur face of the lower limb '2 la is similarly formed with the continuous curve 35a that merges with the intercontinuous curve 38a that joins with the hand grip 25.

When the string is applied to the bow, it is applied in the manner illustrated in Figures 6 to 9 inclusive. The limbs 2i and 2Ia are bent reversely from the positions shown in Figure 1 and the loops of the string are slipped over the projections 24. The limbs 2! and 2m will then be retained in this reversely bent position, the string lying in the grooves 23 formed in the nooks 22.

' t will be understood that the face side. of the how when in use will be in compression while its back side will be in tension. For this reason I use different types of resin at the face and back of the bow. At the back, which is in tension, I employ a flexible polyester resin. This polyester will have sumcient extensibility to prevent local crackin during i-lexure. :The back-of the bow, which is inrtension, is made with aresin which has substantially the same ability to elongate or stretch as the fiber used. In the case of glass fiber the resin used would be designed to have a minimum of 3% elongation. In other words, it will elongate uptoacertain amount then come back to its original condition, that is, it will have sufficient elasticity. A suitable resin for this purpose is a blend of Paraplex P-13 plus Paraplex P-43 (which are blends of alkyds and monomeric styrene), for example, 85 parts Paraplex P-43 to parts Paraplex P-l3, which are made by The Resinous Products Division of Rohm and Haas Company. On the other hand-atthe face, which is in compression, I have found that it is desirable to use arigid polyester resin which will have greater compressive strength. Asuitable rigid polyester resin-is composed entirely of Paraplex 1 -43. The compressive strength of this type of resin can be increased by the use of an inert mineral filler, such'as calcium carbonate to about by weight based on the resin. The central section it may be of one type of resin preferably that type which will have the greater compressive strength.

The arrangementof thepdiifere-nt types of resin in the'bow is illustrated by the diagram in Figures 19 and 12. In Figure 10 the-end sections indicated by the arrows designated a will be of the two different types of resins. The center section extending throughout the length indicated by b will be of the one type of resin, that is, that type suitable to resist-compression.

Throughout-the lengths 'a, the diiferent types of resin will be used at the face and the back of each limb. In Figure 12 the thickness of the limb is indicated by the letter T. The fiexiblepolyester and rigidpolyester resins areso arranged that the compressive material will vary from to of T while the tension material will vary from 25 to 50% of -T beingon opposite sides of the neutral aX-is N, whose position-will vary dependingupon the relative amounts oil-compressive and tension material. In addition, the cross-section of theiimb is-so :shaped thatthe face has increased compressive strength. The area of the face is greater than that -of;theback. For example the width-of the-face-is-indicated by the letter F in Figure l2 is greater than that of the width of the back which is indicated by the letter B. For example the dista-nce B- may be r and the distance F, a: plus 10%. Thus; three factors are used for compensating for the fact thatthis type of resinous material inherently has .less'compressive strength than'tensionalrstrength. These three factorsare the use .:of different types of resins, the use of mineralfiller, in the face resin, and the increased area at the face.

It willbe apparent thatJthe bow made according to my invention will havetbetter characteristics than bows made either of wood or metal. Ehe im-proved characteristics-are. not only .due to the use of fiber reinforced resinisbut'are also. due to the shape of my bow.

Having thus describedt my invention, .what I claim is:

1. archery. bowformed 'lentirelyxas: a single unit consisting.- solely of thermosettingrresins :of

different polyester types reinforced with glass fibers which extend longitudinally of the bow substantially parallel with the axis thereof, said bow having oppositely-extending flexible limbs, each limb of the bow consisting of a rigid polyester resin at the face reinforced with the longitudinally extending glass fibers to more effectively resist compression and a flexible polyester resin at the back reinforced with the longitudinally extending glass fibers to more effectively resist elongation.

2. An. archery bow according to claim 1 wherein the compression resin forms 50 to 75% of the cross-sectional area of the bow limbs and the flexible resin forms 25 to 50% of the cross-sectional area of the bow limbs.

3. A bow according to claim 2 wherein the face of each bow limb is of greater area than the back thereof.

4. A bow according to claim 3 which comprises a central heavy handle section and the opposed flexible limbs.

5. A bow according to claim 4 wherein each limb comprises a relatively thin flexible outer portion which is joined to the heavy handle section by means of a portion which gradually increases in thickness.

6. A bow according to claim 5 wherein brush necks are formed integral on the faces of the outer ends of the limbs.

7. A bow according to claim 6 wherein arrow rests are molded on each side surface of the central section above the hand grip thereof.

8. A bow according to claim 7 wherein the heavy handle section is provided with transverse openings to reduce weight.

9. A bow according to claim 4 wherein the opposed limbs are of substantially S form in side elevation.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Article in The Family Circle, vol. 11, No. 22, November 26, 1937, pp. 18 and 19.

Article in American Bowman-Review, vol, 15, No. 6, January 1946, pp. 5 and 6.

Article in American Bowman-Review, vol. 15, No. 7, February 1946, p. 8.

Article in American Bowman-Review, vol. 15, No, 10, May 1946, p. 6.