US3923036A

US3923036A - Bow structure

Info

Publication number: US3923036A
Application number: US415011A
Authority: US
Inventors: Thomas Paul Jennings; John Monroe Williamson; Carl Sumida
Original assignee: Jennings Compound Bow Inc
Current assignee: MUFG Union Bank NA; Kidde Inc
Priority date: 1973-11-12
Filing date: 1973-11-12
Publication date: 1975-12-02
Anticipated expiration: 1992-12-02

Abstract

A compound bow structure including upper and lower limbs joined to a lightweight metal handle section having an offset portion which defines a window for discharge of an arrow. The offset portion also includes a ribbed surface with cross ribs positioned in planes generally transverse to the plane of bending of a bow. The handle section also includes side ribs positioned adjacent the front and rear surfaces of the handle section in planes generally transverse to the bending plane of a bow. The side ribs and cross ribs are joined to form a ribbed structure with the cross ribs extending from the side ribs in generally diagonal directions with respect to the axis of the handle section and the cross ribs and side ribs forming recessed void regions in the ribbed surface which are bounded by walls formed of the cross ribs and side ribs.

Description

United States Patent 1191 1111 3,923,036 Jennings et al. Dec. 2, 1975 [5 BOW STRUCTURE 3,702,702 11/1972 Hoult 273/73 J [75] Inventors: Thomas Paul Jennings, Sun Valley;

John Monroe Williamson Primary Examiner-Richard J. Apley Hollywood; Carl Sumida, L05 I Assistant Examiner-William R. Browne Angeles, n f Calif Attorney, Agent, or Firm-Ellsworth R. Roston [73] Assignee: Jennings Compound Bow, Inc.,

North Hollywood, Calif. ABSTRACT 22 2 97 A compound bow structure including upper and lower limbs joined to a lightweight metal handle section hav-v [21] Appl' 415,011 ing an offset portion which defines a window for dis- I charge of an arrow. The offset portion also includes a [52] s Cl 124/30 124/3O 124/24 R ribbed surface with cross ribs positioned in planes gen- 51 Int. cm F41B 5/00 erally transverse to the Plane of bending of The [58] pick! f Search 124/24 R, 23 R, 41, 30 R handle section also includes side ribs positioned adja 124/3O A, 273/73 J cent the front and rear surfaces of the handle section in planes generally transverse to the bending plane of [56] References Cited a UNITED STATES PATENTS The side ribs and cross ribs are joined to form a ribbed 2,307,021 1/1943 Cordrey et al. 124 23 R structure with the Cross ribs extending from the side 2,642,66 6/1953 Fredrickersom" 124/24 R X ribs in generally diagonal directions with respect to 2,689,559 9 1954 Meyer 124/24 R the axis of the handle Section and the Cross ribs and 2,714,377 8/1955 Mulkey 124/24 R side ribs forming recessed void regions in the ribbed 2,736,309 2/1956 Hoffman.... 124/23 R surface which are bounded by walls formed of the 2,842,1l3 7/1958 Roper l24/24 R ross ribs and ide ribs. 3,486,495 12/1969 Allen 124/24 R 3 3,518,980 Hamm 124/26 20 Claims, 10 Drawing Figures 3 US. Patent Dec. 2, 1975 Sheet1of2 3,923,036

a I q fii lzh o a c US. Patent Dec. 2, 1975 Sheet 2 of2 3,923,036

BOW STRUCTURE BACKGROUND OF THE INVENTION Compound bows are now in wide use by archers, both for hunting and in archery competition. For a detailed description of a compound bow and its mode of operation, reference is made to US. Pat. No. 3,486,495, issued Dec. 30, 1969.

In general, a compound bow is composed of a handle section having upper and lower limbs supported by the handle section. A bow string is connected to the extremities of the upper and lower limbs through bow string pulleys which may be eccentrically mounted at the ends of the limbs. Draw cables are also connected to the bow string pulleys with the draw cables position'ed inwardly from the bow string in crossed array. The draw cables pass over draw pulleys and the inner ends of the draw cables are secured to the handle section of the bow. This arrangement of cables and pulleys permits the use of relatively short and rigid limbs in the construction of the bow.

The structure and function of a compound bow are known to the art. Thus, the above description of a compound bow is presented merely by way of background to the present invention.

Due to the nature of a compound bow with relatively short and rigid limbs which are flexed during draw of the bow, high stresses are imposed on the handle section of the bow. The bow limbs are interchangeable such that the draw weight of the bow may be increased by replacing the bow limbs with heavier and stiffer limbs. To make the handle section of the bow compatible with the replacement limbs in increasing the draw weight of the bow, the handle section must be designed to carry the stresses imposed by the heaviest and stiffest bow limbs.

In designing a handle section fora compound bow, it is known to provide the handle section with an offset portion defining a sighting window. Thus, for example, a handle section may include an axial portion which lies along the bending axis of the bow and an offset portion in which the material of the handle section is laterally displaced from the axial portion of the handle section.

The offset portion provides lateral displacement of the handle section near its center. In usage, the shaft of an arrow is positioned within the offset portion so that the shaft of the arrow is closely aligned with the bow axis during draw of the bow and discharge of the arrow. Through use of a sighting window, the archer is able to obtain greater accuracy by having the shaft of the arrow in alignment with the bow string and the bending axis of the bow. Moreover, the archer can more readily sight along the arrow toward the target by, viewing the target through the sighting window.

Many problems may be encountered with a compound bow having a handle section with an offset portion defining a sighting window. The offset portion imposes greater stresses on the handle section during draw of the bow and the handle section of the bow will generally have to be made larger and stronger to resist these stresses. This, however, makes the handle section heavier which is a disadvantage. Also, the use of a larger handle section will make the handle more difficult to grip by the archer.

The weight of a compound bow is quite important in terms of its acceptance by archers. If the bow is too heavy, it will be more difficult to hold in a steady position during an archery contest. In field use of the bow, its weight is perhaps of even more importance since the bow will have to be carried by the archer over long distances while stalking game..Thus, if the weight of the bow makes it burdensome to carry in the field, its acceptance by archers may be very limited.

The use of a bow having a heavier draw weight is advantageous for field usage where added draw weight provides greater striking power in bringing down large game. In compound bows of heavier draw weight, the upper and lower bow limbs will be heavier than bow limbs for a lesser draw weight. If the heavier limbs are then coupled with a heavier handle section, this will accentuate the problem of weight. This may, then, present the archer with the dilemma of reducing the weight by using a bow having a lower draw weight or of going to a different type of bow such as a recurved bow.

In view of the above problems, it would be desirable if a compound bow could be provided with a handle section which is both strong and light and, yet, also provides an offset portion defining a sighting window. Such a bow would meet the demands of archers for a bow construction with a sighting window for greater accuracy. Also, such a bow would not have the disadvantage of being so heavy as to make the bow unacceptable for field usage.

SUMMARY OF THE INVENTION In providing a solution to the aforementioned problems, the present invention provides a compound bow with a handle section which is strong, light in weight, and also providesan offset portion defining a sighting window. In the present construction, the handle section is formed of a lightweight metal and the offset portion of the handle section includes a ribbed surface. The ribbed surface provides cross ribs and side ribs positioned in planes that are transverse to the plane of bending of the bow with the side ribs being placed adjacent the front and rear surfaces of the handle section.

The side ribs or! the offset portion are joined to the cross ribs with the cross ribs extending from the side ribs in directions that are diagonal to the axis of the handle section. The intersection of the cross ribs and side ribs form recessed void regions in the ribbed surface which are bounded by rigid connection of the cross ribs and side ribs. The weight of the handle section is, thus, reduced due to the void regions. Also, however, the handle section has resistance to shear and bending forces applied in the plane of bending of the bow.

The diagonal positioning of the cross ribs with respect to the axis of the handle section translates shear forces in the handle section into compressive forces in the cross ribs. Moreover, the rigid connection of the cross ribs and side ribs provides strength in resisting bending forces applied to the handle section in the bending plane of the bow.

The handle section of the compound bow may also include curved regions which join the offset portion to the axial portion of the handle section. The curved regions may be strengthened to resist a twisting moment applied to the curved regions during bending of the bow along its plane of bending.

To strengthen the handle section of the bow, the curved regions of the handle section may include spaced curved ridges positioned transversely to the plane of bending of the bow. The curved ridges may be positioned in planes that are parallel to the axis of the handle section and also the curved ridges may be positioned on a surface which is convexly curved toward the axis of the handle section.

Preferably, the ribbed surface is formed on the outer surface of the offset portion, i.e., on the surface away from the sighting window. Additionally, the ribbed surface may include first cross ribs extending in first diagonal directions andsecond cross ribs extending in second diagonal directions with respect to the axis of the handle section. The first and second cross ribs preferably intersect with the first cross ribs to form recessed void regions having a diamond configuration with the diamond shaped regions positioned centrally of the ribbed surface. Additionally, the first and second cross ribs may form received void triangular regions through intersection with the side ribs. i

The front and rear surfaces of the offset portion may converge outwardly, i.e., in the direction of the connection of the handle section to the upper limb. Thus, the outboard regions of the offset portion may have a smaller cross sectional area while the inboard regions of the offset portion have a larger cross sectional area.

With outward convergence of the front and rear surfaces of the offset portion, the direction of the cross ribs may uniformly change in proceeding from the larger area to the smaller cross sectional area of the offset portion. The cross ribs at the larger cross sectional area preferably form a lesser angle with the axis of the handle section while cross ribs at the smaller cross sectional area form a greater angle with the axis of the handle section. In this manner, the stiffness of the offset portion is increased at the smaller cross sectional area. Bending of the offset portion may, therefore, be made to occur in the inboard regions which have a larger cross sectional area and a larger section modulus.

In providing first and second cross ribs, the directions of both the first and second cross ribs may be uniformly changed in proceeding from the larger to the smaller cross sectional area of the offset portion. With a lesser angle formed between first and second cross ribs with the handle axis at the larger cross sectional area, the diamond shaped void regions will be larger in the inboard regions of the offset portion. The greater angularity between the first and second cross ribs and the axis of the handle section in the outboard regions provides diamond shaped recesses which are smaller in size. In this manner, the size of the diamond shaped recesses may be uniformly diminished in size in proceeding from the larger to the smaller cross sectional area of the offset portion. Thus, the stiffness of the offset portion may be increased at the smaller cross sectional area to provide bending of the offset portion in the inboard regions having a larger cross sectional area and a larger section modulus.

The handle grip of the handle section may define a curved surface which is contoured to fit the hand with the size of the handle not being so large as to be unwieldy or difficult to grip by the archer. For ease in usage, the handle grip may be canted in a forward direction, i.e., with the upper portion of the handle being positioned forward of the lower portion of the handle. The compound bow may then be more easily held in an erect position by grasping the handle with the hand and wrist joint of the archer being inclined downwardly. In this position of the archers hand, the wrist joint is under less strain so that the bow may be held steadier during draw and discharge of an arrow.

BRIEF DESCRIPTION OF THE DRAWINGS Reference is made to the accompanying drawings which are merely illustrative of an embodiment of the invention and in which: a

FIG. 1 is a side elevational view of a compound bow having a handle section with upper and lower limbs connected to the handle section;

FIG. 2 is an exploded perspective view of a support bracket assembly to show the manner in which it is used in connecting an upper limb to the handle section;

. FIG. 3 is a front elevational view of the handle section of FIG. 1 illustrating an offset portion of the handle section which defines a sighting window;

FIG. 4 is a right side elevational view of the handle section of FIG. 3;

FIG. 5 is a rear elevational view ofthe handle section of FIG. 3;

FIG. 6 is a sectional view of the handle section taken along the line 66 of FIG. 4;

FIG. 7 is a sectional view through the handle section along the line 77 of FIG. 4;

FIG. 8 is a sectional view taken along the line 8-8 of FIG. 4; I

FIG. 9 is a side elevational view of the handle section taken along the line 99 of FIG. 5, and

FIG. 10 is a perspective view which illustrates the ridges in the curved regions that connect the offset portion to the axial portions of the handle section.

DETAILED DESCRIPTION A compound bow 2 illustrated in FIG. 1 includes a handle section 4 connected to and supporting an upper limb 6 and a lower limb 8. A handle grip 10 is formed integrally with the handle section 4 with

support bracket assemblies

12 and 14 connecting the upper limb 6 and the lower limb 8 to the handle section.

A bow string'16 is connected through

bow string cables

18 and 20 to eccentrically mounted

pulleys

22 and 24 which are rotatably positioned within slots formed in the ends of the upper and

lower limbs

6 and 8. The

cables

18 and 20 are fixedly connected to their respective pulleys and are confined within slots in their respective pulleys. Draw

cables

26 and 28 are fixedly connected at their outer ends to

respective pulleys

22 and 24 with the outer ends of the draw cables confined within slots in their respective pulleys. The slots in

pulleys

22 and 24 which contain the ends of the

draw cables

26 and 28 are offset and separate from the slots in the pulleys which contain the

bow string cables

18 and 20. Thus, the

bow string cables

18 and 20 are not directly connected to the

draw cables

26 and 28 but forces in the bow string cables are transmitted to

pulleys

22 and 24 which in turn transmit these forces to the draw cables.

As illustrated, the inner ends of the

draw cables

26 and 28 are respectively connected to the

support bracket assemblies

12 and 14. Draw cable 28 leads from support bracket assembly 12, passing over a draw pulley 32 and then to the pulley 24. Likewise, draw cable 26 leads from support bracket assembly 14 over a draw pulley 30 and then the bow string pulley 22. The draw pulleys 30 .and 32 may be secured to the bow limbs in any convenient manner. A connector 34 is illustrated as supporting the draw pulley 30 with respect to the lower limb 8 while a connector 36 supports the draw pulley 32 with respect to the upper limb 6.

The eccentric mounting of bow string pulleys 22 and 24 provides a mechanical advantage during draw of the bow 2. When the draw force reaches a certain level, the

pulleys

22 and 24 rotate about their eccentric mountings. On rotation of the pulleys 22 and-24, the length of the upper and

lower limbs

6 and 8 is effectively increased by the amount of eccentricity of the pulleys. Thus, for example, with a bow having a pull or draw weight of 50 pounds force and a draw length of 26 inches, the maximum draw force of 50 pounds may be required when the arrow is drawn to a length-of 22 inches. During draw of the arrow from 22 to 26 inches,

the draw force may then decrease due to the rotation of the

pulleys

22 and 24. Thus, when the bow is fully drawn, the force required to hold the arrow may be only 40 pounds, even though the bow is designed for a pull or draw weight of pounds. On release of the arrow, the initial force exerted would be only 40 pounds. However, this force would increase and would reach a maximum of 50 pounds of force during discharge of the arrow.

The compound bow 2 shown in FIG. 1 may also include conventional accessories. Such accessories may include a balance pole 38 mounted on a front surface of the handle section 4 and a sight 40 mounted on the handle section.

As described, the handle section 4 is very strong and yet very light. To provide both strength and light' weight, the handle section 4 may be formed of a metal such as aluminum or an aluminum-magnesium alloy. To eliminate weight, the handle section 4 may include cross ribs positioned transversely to the bending axis of the bow and positioned in diagonal directions with respect to the axis of the handle section.

FIG. 2 illustrates the components of the upper support bracket assembly 12 in supporting the upper limb 6 with respect to the handle section 4. The handle section 4 includes a laterally offset portion 44 connected to an upper axial portion 48 through a curved portion 46. To reduce the weight of the upper axial portion 48, while providing strength, cross ribs 50 are positioned in planes transverse to the plane of bending of the handle section 4 and with the cross ribs positioned diagonally with respect to the axis of the handle section. The cross ribs 50 are interconnected with side ribs 51 positioned adjacent front and

rear surfaces

53 and 55. Cross ribs 50 are rigidly connected to side ribs 51. to form recessed triangular void regions 57 bounded by the cross ribs and side ribs. The void regions 57 provide a lightweight structure while the positioning of the cross ribs 50 and side ribs 51 provide a structure having considerable strength in shear and bending.

A T-bar 52 positioned at the upper extremity of axial portion 48 defines a curved bearing support surface 54 which bears against a curved rocker surface 58 formed on the underside of upper limb 6. In securing the upper limb 6 to the handle section 4, a bolt 64 is positioned within a slot 60 with the head of the bolt bearing against the outer surface of the upper limb through a series of washers 62. The bolt 64 engages a threaded aperture 66 in a boss 68 which extends diagonally from the front surfaces 53. With the upper limb 6 thus secured to the handle section 4, the position of the upper limb may be altered by threading of the bolt 64 into the aperture 66. In this manner, the draw weight of the bow may be increased to some extent without replacement of the

limbs

6 and 8.

Side bosses 70 extend from the boss 68 to engage apertured side plates 74 and .76 that bear against either side of the axial portion 48. Additionally, the

side plates

74 and 76 are supported through contact with side bosses 72 with screws 78 extendingthrough apertures in the side plates into threaded

apertures

80 and 82 in the

bosses

70 and 72. The upper portions of the side.

plates

74 and 76 bear against the end surfaces of the T-bar 52 and are secured thereto by screws 84 which engage threaded apertures 86 in the T-bar.

With the

side plates

74 and 76 thus secured to the T-bar 52 and the axial portion 48, a cable worm adjustment assembly 88 is secured to the side plates for support and tensioning of the draw cable 28. A hollow shaft 96 of assembly 88 passes through apertures 98 and 100 of the

side plates

74 and 76. The shaft 96 may be secured within apertures 98 and 100 by a pin or cotter key (not shown) which passes through an opening 91 in the shaft. The cable 28 extends through a cable opening 93 with the end of the cable secured within hollow shaft 96 by an end enlargement (not shown). A handle 95 may then be used to rotate the shaft 96 to wrap the draw cable 28 about the shaft. When the draw cable 28 has, thus, been suitably tensioned, the position of the shaft 96 may be fixed by inserting a screw 92 through an aperture in a positioning tab into engagement with an aperture 97 in side plate 74. The screw 92 may be held in place by threaded engagement with a nut 94 which bears against the inner surface of side plate 74.

The handle section 4 is shown in front elevational view in FIG. 3 in which the offset portion 44 defines a sighting window 104. The offset portion 44 is connected to upper axial portion 48 through the curved portion 46. Similarly, the offset portion 44 is connected to a lower axial portion 101 through a curved portion 102. The lower axial portion 101 includes the handle grip 10 which is positioned immediately below curved portion 102. The curved portion 102 also defines a shelf 106 which assists in supporting an arrow shaft within the sighting window 104 in approximate alignment with the bending axis of the handle section 4. The lower axial portion 101 also includes lower side bosses 103, a boss 105, a T-bar 107, and a curved bearing support surface 109. These structural elements function in the manner described with regard to FIG. 2 in securing the lower limb 8 to the handle section 4.

The handle section 4 shown in side elevation in FIG. 4 includes side ribs 108 positioned adjacent the front and

rear surfaces

53 and 55 of the offset portion 44. Cross ribs 113 are joined to the side ribs 108 with the cross ribs positioned in planes transverse to the bending axis of handle section 4 and the cross ribs positioned diagonally with respect to the axis of the handle section. As indicated, first cross ri-bs 113a are positioned in one diagonal direction while second cross ribs 1l3b are positioned in a second diagonal direction to intersect the first cross ribs.

The front surfaces 53 and rear surface 55 may converge outwardly, as shown, such that the cross sectional area of the offset portion 44 diminishes as the surfaces converge. As the cross sectional area of the offset portion 44 diminishes, the diagonal positioning of the cross ribs 113a and 1 13b is gradually changed. In proceeding outwardly, the angles made by the

cross ribs

113a and 113b with the axis of the handle section 4 are gradually increased. The intersection of cross ribs 113a and 1l3b forms centrally positioned recessed diamond shaped voids 110 bounded by the cross ribs. Due to the increasing angle between the cross ribs 113a and 113k and the axis of the handle section 4, the size of the centrally positioned diamond shaped voids 110 decreases uniformly in proceeding outwardly along the offset portion 44. This provides the offset portion 44 with greater stiffness in its outboard regions which have a smaller cross sectional area and less stiffness in its inboard regions which have a larger cross sectional area. Bending of the offset portion 44 during draw of the bow is, thus, made to occur in the inboard regions of the offset portion having a greater cross sectional area and a greater section modulus.

The rigid connection of the

intersecting cross ribs

113a and 113b with each other and also with side ribs 108 provides a construction having high strength in bending. Additionally, the diagonal positioning of the cross ribs 113a and ll3b with respect to the axis of the handle section 4 provides greater strength in shear in which the shear forces are transferred into the diagonally positioned cross ribs.

For further weight reduction, front slots 114 may be formed in the inner surface 11 1 of the offset portion 44 (see FIG. 6). Similarly, slots 116 may be formed in the outer surface of the offset portion 44. The intersection of the cross ribs 113a and 1 13b with side ribs 108 forms recessed triangular voids 1 12 which are bounded by the cross ribs and side ribs 108.

Slots 118 may also be formed in the handle grip (see FIG. 7) with corresponding slots 120 being formed on the opposite side of the handle grip. Also, to reduce weight, slots 122 may be formed in the lower axial portion 101.

Turning to the upper axial portion 48, diagonal ribs 126 on the inner surface of the upper axial portion intersect converging side ribs 124 to form centrally positioned recessed triangular voids 128. The voids 128 are bounded by the diagonal ribs 126 and side ribs 124. Also, front slots 130 may be formed in the upper axial portion 48 to reduce the weight of the axial portion.

The lower axial portion 101 is strengthened by means of downwardly converging side ribs 132 and diagonal ribs 134 positioned in planes transverse to the bending axis of the handle section 4 with the diagonal ribs 134 positioned at an angle to the axis of the handle section. The diagonal ribs 134 are rigidly connected to side ribs 132 to form centrally positioned recessed triangular voids 136. The angle of the diagonal ribs 134 with respect to the axis of the handle section 4 increases uniformly in progressing downwardly away from the handle grip 10. Thus, the triangular voids 136 decrease uniformly in size to provide increased stiffness in the outboard regions having a smaller cross sectional area and less stiffness in the inboard regions having a greater cross sectional area. By reason of this construction, bending of the lower axial portion 101 tends to occur in its inboard regions having a greater cross sectional area.

FIG. 5 is a rear elevational view of the handle section 4 as it would be viewed by the archer during draw of a compound bow embodying the handle section. As thus viewed, the offset portion 44 is offset toward the right arm of the archer. Most archers are right-handed and draw a bow with their right arm while supporting the bow with their left. Thus, lateral displacement of the offset portion 44 toward the right hand of the archer accommodates the handle section 4 for use by a right-handed archer. The handle section 4 may, of course, also be used by a left-handed archer. Also, if desired, the displacement of the offset portion 44 may be reversed from the position shown in FIG. 5, and may be laterally displaced toward the left hand of the archer.

FIG. 6, as mentioned previously, is a sectional view taken along the line 6-6 of FIG. 4. As shown, the cross section of the offset portion at this point is not uniform. The

slots

114 and 116 positioned adjacent the front surface 53 provide a cross sectional configuration having an H-shape. This is in contrast to the channel shape of the cross sectional area adjacent the rear surface 55 as viewed on a plane cutting through one of the centrally positioned diamond shaped recesses 110.

FIG. 7, referred to previously, illustrates the cross sectional configuration of the handle grip 10 which may include

slots

118 and 120 designed to lessen the weight of the handle grip. As indicated in FIG. 4, the handle grip 10 is canted rearwardly with the upper portion of the handle grip being positioned forwardly of the lower portion. This permits the handle grip to be grasped by the archer with the hand inclined downwardly and wrist joint flexed downwardly. By holding the handle in this manner, it is easier to maintain the handle section 4 in a steady position.

FIG. 8 is a sectional view along the line 8-8 of FIG. 4 with the slots 122 in the inner surface of the lower axial portion 101 aligned with slots in the outer surface of the lower axial portion. Similarly, centrally positioned triangular recesses 136 on the inner surface of the lower axial portion 101 are aligned with similarly positioned triangular recesses 138 in the outer surface of the lower axial portion. This provides the lower axial portion 101 with light weight as well as strength in bending and shear.

FIG. 9 is a partial side elevational view of the outer surface of the handle section 4. As described previously, the intersecting cross ribs 113a and 1l3b form with the side ribs 108, a plurality of centrally positioned diamond shaped voids 110, and side triangular voids ll2.which gives the offset portion 44 considerable strength in both shear and bending. Also, by reason of the gradually increasing angularity of the cross ribs 113a and ll3b with respect to the axis of the handle section 4, the side triangular voids 112 and centrally positioned diamond shaped voids 110 diminish in size in the outboard regions of the offset portion 44. This provides the outboard regions with increased stiffness such that bending of the offset portion 44 occurs in the inboard regions having a larger cross sectional area and a higher section modulus.

Unlike the offset portion 44, the upper axial portion 48 has a ribbed construction on both its outer and inner surfaces. Thus, the upper axial portion 48 includes diagonal ribs 140 which are rigidly joined to side ribs 144 to form centrally positioned triangular voids 142.

The structure of the

curved portions

46 and 102 which connect the offset portion 44 to the remainder of the handle section 4 is illustrated in FIG. 10. The curved portion 46 includes

ridges

146, 148 and 150 p0 sitioned on the convexly curved surface of the curved portion 46. A recessed void region 152 is bounded by the

ridges

146 and 148 while a recessed void region 154 is bounded by

ridges

148 and 150. The

ridges

146, 148 and 150 are positioned in planes which are generally parallel to the axis of the handle section 4 with the depth of the ridges providing the curved portion 46 with considerable strength.

Similarly, the curved portion 102 includes

ridges

156, 158 and 160 positioned on the convexly curved surface of the curved portion. The

ridges

156 and 158 are positioned in planes which are generally parallel to the axis of the handle section 4 while the ridge 160 is positioned on an angle to the axis of the handle section. A recessed void region 162 is bounded by the

ridges

156 and 158 while a recessed void region 164 is bounded by

ridges

158 and 160. The depth of the'

ridges

156, 158 and 160 provides the curved portion 102 with considerable strength. Also, the volume of the

void regions

162 and 164 contributes to the light weight of the handle section 4 as do the

void regions

152 and 154 in the upper curved portion 46.

We claim: 1. In a handle section for a compound bow, said handle section having a front surface, a back surface, a longitudinal axis and a plane of bending passing through said longitudinal axis and being generally perpendicular to said front surface, said back surface and passing through a taut bow string when the handle section is connected to bow limbs; said handle section having upper and lower ends for connection to an upper limb and a lower limb; said handle section being formed of a lightweight metal and including an offset portion which is offset from said longitudinal axis and which portion lies in a plane that is offset from and generally parallel to the plane of bending of the handle section with the offset portion defining a window for the discharge of an arrow; said offset portion having a ribbed surface which is generally parallel to said plane of bending with the ribbed surface including cross ribs positioned in planes that are transverse to the plane of bending of the handle section; said ribbed surface including side "ribs positioned in planes transverse to the plane of bending of the handle section with the side ribs being positioned adjacent to the front and rear surfaces of the handle section; said side ribs being joined to said cross ribs with the cross ribs extending from the side ribs in a diagonal direction with respect to the longitudinal axis of said handle section; said cross ribs and said side ribs forming recessed regions in said ribbed surface with the recessed regions being bounded by the rigid connection of the cross ribs and the side ribs, whereby the weight of the handle section is reduced by the empty volume of'the recessed regions, the handle section being resistant to shear and bending forces applied in the plane of bending of the handle section and in the plane of the offset portion with the diagonal cross ribs tending to translate shear forces in the handle section into compressive forces in the cross ribs and the rigid structure of the joined cross ribs and side ribs providing the handle section with resistance to bending in the bending plane of the handle section and in the plane of the offset portion. 2. The handle section of claim 1 including curved regions at either end of said offset portion joining said offset portion to the remainder of the handle section;

said curved regions being strengthened to resist a twisting moment applied to the curved regions during bending of the handle section along its plane of bending.

3. The handle section of claim 2 including spaced curved ridges positioned at said curved regions;

said curved ridges positioned transversely to the plane of bending of said handle section;

said curved ridges positioned in planes parallel to the axis of the handle section, and

said curved ridges positioned on a surface which is convexly curved toward the axis of the handle section.

4. The handle section of claim 1 wherein said ribbed surface is the outer surface of said offset portion.

5. The handle section of claim 1 including first cross ribs extending in first diagonal directions with respect to the longitudinal axis of said handle section;

second cross ribs extending in second diagonal directions with respect to the longitudinal axis of said handle section;

said first and second cross ribs intersecting to form recessed regions having a diamond configuration which are positioned centrally of said ribbed surface, and

the first and second cross ribs together with the side ribs forming recessed regions having a triangular configuration positioned adjacent the front and rear surfaces of the handle section.

6. The handle section of claim 5 wherein said front and rear surfaces converge outwardly to provide the offset portion with a smaller cross sectional area adjacent the end of the handle section which is connectable to an upper limb and a larger cross sectional area adjacent the connection of the offset portion to the remainder of the handle section.

7. The handle section of claim 6 wherein the directions of the cross ribs are uniformly changed in proceeding outwardly from the larger cross sectional area toward the smaller cross sectional area;

the cross ribs in the larger cross sectional area of the offset portion forming a lesser angle with the axis of the handle section than the cross ribs in the smaller cross sectional area of the offset portion, and

the recessed diamond shaped regions formed by intersection of the first and second cross ribs diminishing in size in proceeding from the larger cross sectional area'to the smaller cross sectional area of the offset portion,

whereby the stiffness of the offset portion is greater in the regions having the smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

8. The handle section of claim 1 wherein said front and rear surfaces converge outwardly to provide the offset portion with a smaller cross sectional area adjacent the end of the handlesection which is connectable to an upper limb and a larger cross sectional area adjacent the connection of the Wmumuwummwmimmm in offset portion to the remainder of the handle section.

9. The handle section of claim 8 wherein the directions of the cross ribs are uniformly changed in proceeding outwardly from the larger cross sectional area toward the smaller cross sectional area;

the cross ribs at the larger cross sectional area of the offset portion forming a lesser angle with the longitudinal axis of the handle section than the cross ribs at the smaller cross sectional area of the offset portion,

whereby the stiffness of the offset portion is greater in regionshaving a smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

10. The handle section of claim 1 including a handle positioned on the axis of the handle section;

said handle being positioned immediately below the offset portion, and

the lower end of the offset portion being joined to the handle.

11. The handle section of claim 10 wherein said handle has a curved surface contoured to fit the hand, and

the handle is canted in a forward direction with the upper portion of the handle positioned ahead of the lower portion of the handle,

whereby the handle section is more easily held in an erect position by grasping the handle with the grasping hand and wrist joint inclined downwardly.

12. In a compound bow having a handle section and an upper and a lower limb connected to said handle section, the improvement comprising:

said handle section having a front surface, a back surface, a longitudinal axis and a plane of bending passing through said longitudinal axis and being generally perpendicular to said front surface, said back surface, and passing through a taut bowstring with said handle section connected to said bow limbs;

said handle section having upper and lower ends connected respectively to said upper and lower limbs;

said handle section being formed of a lightweight metal and including an offset portion which is offset from said longitudinal axis and which portion lies in a plane that is offset from and generally parallel to said plane of bending with the offset portion defining a window for the discharge of an arrow;

said offset portion having a ribbed surface which is generally parallel to said plane of bending with the ribbed surface including cross ribs positioned in planes that are transverse to the plane of bending of the handle section;

said ribbed surfaces including side ribs positioned in planes transverse to the plane of bending of the handle section with the side ribs being positioned adjacent to the front and rear surfaces of the handle section;

said side ribs being joined to said cross ribs with-the crossribs extending from the side ribs in a diagonal direction with respect to the longitudinal axis of said handle section;

said cross ribs and said side ribs forming recessed regions in said ribbed surface with the recessed regions being bounded by-the rigid connection of the cross ribs and the side ribs,

whereby the weight of the handle section is reduced by the empty volume of the recessed regions, the handle section being resistant to shear and bending forces applied in the plane of bending of the handle section and in the plane of the offset portion with the diagonal cross ribs tending to translate shear forces in the handle section into compressive forces in the cross ribs and the rigid structure of the joined cross ribs and side ribs providing the handle section with resistance to bending in the bending plane of the handle section and in the plane of the offset portion. 13. The compound bow of claim 12 including curved regions at either end of said offset portion joining said offset portion to the remainder of the handle section; said curved regions being strengthened to resist a twisting moment applied to the curved regions during bending of the bow along its plane of bending. 14. The compound bow of claim 13 including spaced curved ridges positioned at said curved regions; said curved ridges positioned transversely to the plane of bending of said bow; said curved ridges positioned in planes parallel to the axis of the handle section, and said curved ridges positioned on a surface which is convexly curved toward the axis of the bow. l5. The-compound bow of claim 12 wherein said ribbed surface is the outer surface of said offset portion.

16. The compound bow of claim 12 including first cross ribs extending in first diagonal directions with respect to the longitudinal axis of said handle section; second cross ribs extending in second diagonal directions with respect to the longitudinal axis of said handle section; said first and second cross ribs intersecting to form recessed regions having a diamond configuration which are positioned centrally of said ribbed surface, and the first and second cross ribs together with the side ribs forming recessed regions having a triangular configuration positioned adjacent the front and rear surfaces of the handle section. 17. The compound bow of claim 16 wherein said front and rear surfaces converge outwardly to provide a smaller cross sectional area adjacent the connection between the handle section and the upper limb and a larger cross sectional area adjacent the connection of the offset portion to the remainder of the handle section. 18. The compound bow of claim 17 wherein the directions of the first and second cross ribs are uniformly changed in proceeding outwardly on the offset portion from the larger cross sectional area toward the smaller cross sectional area; the cross ribs in the larger cross sectional area of the offset portion forming a lesser angle with the axis of the handle section than the cross ribs in the smaller cross sectional area of the offset portion,

and h .the recessed diamond shaped regions diminishing in size in proceeding from the larger cross sectional area to the smaller cross sectional area of the offset portion,

whereby the stiffness of the offset portion is greater in regions having the smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

19. The compound bow of claim 12 wherein said front and rear surfaces converge outwardly to provide the offset portion with a smaller cross sectional area adjacent the connection between the handle section and the upper limb and a larger cross sectional area adjacent the connection of the offset portion to the remainder of the handle section.

20. The compound bow of claim 19 wherein whereby the stiffness of the offset portion is greater in the regions having the smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

Claims

1. In a handle section for a compound bow, said handle section having a front surface, a back surface, a longitudinal axis and a plane of bending passing through said longitudinal axis and being generally perpendicular to said front surface, said back surface and passing through a taut bow string when the handle section is connected to bow limbs; said handle section having upper and lower ends for connection to an upper limb and a lower limb; said handle section being formed of a lightweight metal and including an offset portion which is offset from said longitudinal axis and which portion lies in a plane that is offset from and generally parallel to the plane of bending of the handle section with the offset portion defining a window for the discharge of an arrow; said offset portion having a ribbed surface which is generally parallel to said plane of bending with the ribbed surface including cross ribs positioned in planes that are transverse to the plane of bending of the handle section; said ribbed surface including side ribs positioned in planes transverse to the plane of bending of the handle section with the side ribs being positioned adjacent to the front and rear surfaces of the handle section; said side ribs being joined to said cross ribs with the cross ribs extending from the side ribs in a diagonal direction with respect to the longitudinal axis of said handle section; said cross ribs and said side ribs forming recessed regions in said ribbed surface with the recessed regions being bounded By the rigid connection of the cross ribs and the side ribs, whereby the weight of the handle section is reduced by the empty volume of the recessed regions, the handle section being resistant to shear and bending forces applied in the plane of bending of the handle section and in the plane of the offset portion with the diagonal cross ribs tending to translate shear forces in the handle section into compressive forces in the cross ribs and the rigid structure of the joined cross ribs and side ribs providing the handle section with resistance to bending in the bending plane of the handle section and in the plane of the offset portion.

2. The handle section of claim 1 including curved regions at either end of said offset portion joining said offset portion to the remainder of the handle section; said curved regions being strengthened to resist a twisting moment applied to the curved regions during bending of the handle section along its plane of bending.

3. The handle section of claim 2 including spaced curved ridges positioned at said curved regions; said curved ridges positioned transversely to the plane of bending of said handle section; said curved ridges positioned in planes parallel to the axis of the handle section, and said curved ridges positioned on a surface which is convexly curved toward the axis of the handle section.

5. The handle section of claim 1 including first cross ribs extending in first diagonal directions with respect to the longitudinal axis of said handle section; second cross ribs extending in second diagonal directions with respect to the longitudinal axis of said handle section; said first and second cross ribs intersecting to form recessed regions having a diamond configuration which are positioned centrally of said ribbed surface, and the first and second cross ribs together with the side ribs forming recessed regions having a triangular configuration positioned adjacent the front and rear surfaces of the handle section.

7. The handle section of claim 6 wherein the directions of the cross ribs are uniformly changed in proceeding outwardly from the larger cross sectional area toward the smaller cross sectional area; the cross ribs in the larger cross sectional area of the offset portion forming a lesser angle with the axis of the handle section than the cross ribs in the smaller cross sectional area of the offset portion, and the recessed diamond shaped regions formed by intersection of the first and second cross ribs diminishing in size in proceeding from the larger cross sectional area to the smaller cross sectional area of the offset portion, whereby the stiffness of the offset portion is greater in the regions having the smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

8. The handle section of claim 1 wherein said front and rear surfaces converge outwardly to provide the offset portion with a smaller cross sectional area adjacent the end of the handle section which is connectable to an upper limb and a larger cross sectional area adjacent the connection of the offset portion to the remainder of the handle section.

9. The handle section of claim 8 wherein the directions of the cross ribs are uniformly changed in proceeding outwardly from the larger cross sectional area toward the smaller cross sectional area; the cross ribs at the larger cross sectional area of the offset portion forming a lesser angle with The longitudinal axis of the handle section than the cross ribs at the smaller cross sectional area of the offset portion, whereby the stiffness of the offset portion is greater in regions having a smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

10. The handle section of claim 1 including a handle positioned on the axis of the handle section; said handle being positioned immediately below the offset portion, and the lower end of the offset portion being joined to the handle.

11. The handle section of claim 10 wherein said handle has a curved surface contoured to fit the hand, and the handle is canted in a forward direction with the upper portion of the handle positioned ahead of the lower portion of the handle, whereby the handle section is more easily held in an erect position by grasping the handle with the grasping hand and wrist joint inclined downwardly.

12. In a compound bow having a handle section and an upper and a lower limb connected to said handle section, the improvement comprising: said handle section having a front surface, a back surface, a longitudinal axis and a plane of bending passing through said longitudinal axis and being generally perpendicular to said front surface, said back surface, and passing through a taut bowstring with said handle section connected to said bow limbs; said handle section having upper and lower ends connected respectively to said upper and lower limbs; said handle section being formed of a lightweight metal and including an offset portion which is offset from said longitudinal axis and which portion lies in a plane that is offset from and generally parallel to said plane of bending with the offset portion defining a window for the discharge of an arrow; said offset portion having a ribbed surface which is generally parallel to said plane of bending with the ribbed surface including cross ribs positioned in planes that are transverse to the plane of bending of the handle section; said ribbed surfaces including side ribs positioned in planes transverse to the plane of bending of the handle section with the side ribs being positioned adjacent to the front and rear surfaces of the handle section; said side ribs being joined to said cross ribs with the cross ribs extending from the side ribs in a diagonal direction with respect to the longitudinal axis of said handle section; said cross ribs and said side ribs forming recessed regions in said ribbed surface with the recessed regions being bounded by the rigid connection of the cross ribs and the side ribs, whereby the weight of the handle section is reduced by the empty volume of the recessed regions, the handle section being resistant to shear and bending forces applied in the plane of bending of the handle section and in the plane of the offset portion with the diagonal cross ribs tending to translate shear forces in the handle section into compressive forces in the cross ribs and the rigid structure of the joined cross ribs and side ribs providing the handle section with resistance to bending in the bending plane of the handle section and in the plane of the offset portion.

13. The compound bow of claim 12 including curved regions at either end of said offset portion joining said offset portion to the remainder of the handle section; said curved regions being strengthened to resist a twisting moment applied to the curved regions during bending of the bow along its plane of bending.

14. The compound bow of claim 13 including spaced curved ridges positioned at said curved regions; said curved ridges positioned transversely to the plane of bending of said bow; said curved ridges positioned in planes parallel to the axis of the handle section, and said curved ridges positioned on a surface which is convexly curved toward the axis of the bow.

15. The compound bow of claim 12 whereiN said ribbed surface is the outer surface of said offset portion.

16. The compound bow of claim 12 including first cross ribs extending in first diagonal directions with respect to the longitudinal axis of said handle section; second cross ribs extending in second diagonal directions with respect to the longitudinal axis of said handle section; said first and second cross ribs intersecting to form recessed regions having a diamond configuration which are positioned centrally of said ribbed surface, and the first and second cross ribs together with the side ribs forming recessed regions having a triangular configuration positioned adjacent the front and rear surfaces of the handle section.

17. The compound bow of claim 16 wherein said front and rear surfaces converge outwardly to provide a smaller cross sectional area adjacent the connection between the handle section and the upper limb and a larger cross sectional area adjacent the connection of the offset portion to the remainder of the handle section.

18. The compound bow of claim 17 wherein the directions of the first and second cross ribs are uniformly changed in proceeding outwardly on the offset portion from the larger cross sectional area toward the smaller cross sectional area; the cross ribs in the larger cross sectional area of the offset portion forming a lesser angle with the axis of the handle section than the cross ribs in the smaller cross sectional area of the offset portion, and the recessed diamond shaped regions diminishing in size in proceeding from the larger cross sectional area to the smaller cross sectional area of the offset portion, whereby the stiffness of the offset portion is greater in regions having the smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.

20. The compound bow of claim 19 wherein the directions of the cross ribs are uniformly changed in proceeding outwardly from the larger cross sectional area toward the smaller cross sectional area; the cross ribs at the larger cross sectional area of the offset portion forming a lesser angle with the longitudinal axis of the handle section than the cross ribs at the smaller cross sectional area of the offset portion, whereby the stiffness of the offset portion is greater in the regions having the smaller cross sectional area and bending of the offset portion occurs in a region having a larger cross sectional area.