Compound Archery Bow

The present invention is directed to compound archery bows, and particularly to improvements associated with compound archery bow handles of mold-formed construction such as cast magnesium.

A general object of the present invention is to provide a compound archery bow that is characterized by reduced manufacture and assembly cost associated with mounting of bow components on the bow handle--e.g., less expensive molds and tooling for the bow handle. A more specific object of the present invention is to provide a compound archery bow having a mold-formed handle of cast magnesium, for example, with improved means for mounting the bow limbs, bow cable guide and/or other bow accessories on the handle. In general, these improvements involve elimination of separate machining operations characteristic of the prior art for drilling and tapping mounting openings in the handle subsequent to the casting operation.

The invention, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:

FIG. 1 is a side elevational view of a compound archery bow in accordance with one presently preferred embodiment of the invention;

FIG. 2 is a fragmentary exploded perspective view of a portion of the bow illustrated in FIG. 1;

FIG. 3 is a fragmentary elevational view of a portion of the bow handle illustrated in FIG. 1, being taken substantially along the line 3--3 in FIG. 1;

FIG. 4 is a sectional view taken substantially along the line 4--4 in FIG. 3;

FIG. 5 is a fragmentary elevational view of a bow showing attachment of a limb to the handle in accordance with a modified embodiment of the invention;

FIG. 6 is a fragmentary view on an enlarged scale of a portion of the limb attachment arrangement illustrated in FIG. 5; and

FIG. 7 is a fragmentary sectional view taken substantially along the line 7--7 in FIG. 6.

FIG. 1 illustrates a compound archery bow 10 that includes a cast magnesium handle 12 having spaced ends 14,16 with flat limb-mounting surfaces 18,20 at an angle to each other. A pair of flexible limbs 22,24 of fiber reinforced resin or other suitable construction are mounted on handle ends 14,16 respectively, and project therefrom away from handle 12. Each limb 22,24 has an associated cable pulley 26,28 rotatably mounted at the handle-remote end or tip thereof. A bow string 30 extends between pulleys 26,28. A pair of cables 32,34 are fastened at one end to limbs 22,24 by tension adjusters 36,38 respectively, and extend to and are trained over the pulley 28,26 at the end of the opposing limb and fastened to drawstring 30. A cable guide 40 is fastened at one end to handle 12, and carries a slider 42 that receives cables 32,34 for guiding motion of the cables as string 30 is drawn and released. To the extent thus far described, bow 10 is of conventional construction.

In accordance with a first aspect of the present invention, bow limbs 22,24 are mounted to respective ends 14,16 of handle 12 by limb-mounting arrangements best illustrated in FIGS. 1-3. A generally rectangular pocket 44 opens laterally outwardly--i.e., laterally of the longitudinal dimension of the handle and to the direction of string draw--adjacent to limb-mounting surfaces 18,20 at each handle end 14,16. A laterally opening channel 46 intersects each pocket 44 and opens to the associated adjacent surface 18,20 at right angles to the surface and the pocket. A lateral slot 48 extends along each planar surface 18,20, having an inner end aligned with the associated channel 46. A nut 50 is loosely removably received in each pocket 46. A screw 52 extends through a series of washers 54,56,58, through an opening 60 in each limb 22,24, and thence through slot 48 into channel 46 so as to be threadably received within nut 50 in pocket 44. A notch 62 at the inner end of each limb 22,24 cooperates with a corresponding projection or boss 64 adjacent to each limb-mounting surface 18,20 to assist in aligning of the limb with the handle during assembly and use.

The limb-mounting arrangement so illustrated in FIGS. 1-3 and described above may be contrasted with the conventional practice of drilling and tapping mounting openings at the respective ends of the handle for threadably receiving screws 52. Pocket 44, channel 46 and slot 48 may be readily formed during the handle-casting operation with no special core pulls, thus requiring no additional or special manufacturing process steps. As best seen in FIG. 1, the pockets 44, channels 46 and slots 48 at both ends of the handle open in the same lateral direction, and are tapered (FIG. 3) at the angle of the casting draft. Nut 50 is a standard and inexpensive hardware element that is assembled to the handle after the casting operation. Thus, the expensive drilling and tapping process of the prior art is essentially replaced by an inexpensive hardware element. In addition, since screws 52 and nuts 50 are readily visible from the side of the bow, they may be observed during adjustment of bow tension, by loosening or tightening screws 52, which helps prevent inadvertent complete loosening of the screws.

In accordance with a second aspect of the present invention also illustrated in FIGS. 1 and 2, a through-opening 70 is formed in handle 12, preferably by a plug positioned in the mold prior to casting of the handle. Opening 70 is of frusto-conical geometry, taping narrowingly from front to back of the handle, which is to say that the end of lesser diameter is adjacent to bow cables 32,34 as best seen in FIG. 1. A conical bushing 72 is removably received within opening 70. Conical bushing 72 has a through-opening 74 that is internally threaded at least adjacent to the axial ends of the bushing. Cable guide 40 is mounted to handle 12 by means of a screw 76 (FIG. 2) that extends through guide 40 to be threadably received within the narrow end of bushing 72. Preferably, the length of bushing 72 is such that the end 73 of lesser diameter does not reach the inner surface of handle 12, as seen in FIG. 1, while the end 75 of greater diameter projects slightly from the outer handle surface. This construction ensures firm seating of the bushing within the handle, while providing a small mounting boss on the outer surface of the handle.

Thus, plug-formed opening 70, in combination with bushing 72 with internally threaded through-opening 74, replaces the drilling and tapping operation conventional in the prior art for providing a threaded opening for mounting of cable guide 40. As screw 76 is tightened to mount cable guide 40, bushing 72 is drawn into handle opening 70, so that bushing 72 is essentially self-tightening in operation. Furthermore, with the outer (wider) end of bushing 72 also being internally threaded, there is thus automatically provided at no additional cost a mounting opening for conventional bow accessories such as a stabilizer or bow-fishing reel.

It is conventional practice to provide a pair of laterally aligned hemispheric bearing bosses 78,80 on the inner face of each limb 22,24 adjacent to the associated mounting screw 52, and to provide correspondingly laterally aligned outwardly opening pockets 82,84 on the opposing faces 18,20 of the handle. The hemispheric bearing bosses are received within the pockets and provide for pivotal motion of the limbs as the mounting screws 52 are loosened and tightened. Bosses 78,80 are formed on a plate 86 that is adhesively secured or otherwise suitably fastened to the inner face of the limb adjacent to the mounting opening.

In accordance with a third aspect of the present invention, the pockets 82,84 are formed as laterally aligned oppositely opening channels that have spherical inner channel ends 88,90 separated from each other by a portion of the handle end that forms a rib 92. The channel ends 88,90 are part-spherical, having the same radius of curvature as bosses 78,80 (which are identical to each other), and having a depth that is less than the height of the bearing bosses. Channels 82,84 have angulated lower surfaces, as best seen in FIG. 4, at the draft angle of the handle mold. This construction has two advantages. First, the part-spherical inner ends 88,90 of channels 82,84 cooperate with the hemispheric contour of bearing bosses 78,80 to render the bearing/channel arrangement self-centering during assembly. Projection 64 cooperating with notch 62 at the handle end, and the bearing/boss arrangement described immediately above, provide three-point location of the limb end with respect to the handle while accommodating tolerance variations during the molding operation. Furthermore, with channels 82,84 being open to the sides of the handle and at the draft angle of the handle, the mold elements do not tend to lock up with the handle during the casting operation, as has often been the case with the prior art.

FIGS. 5-7 illustrate a modified limb-mounting arrangement in accordance with a fourth aspect of the present invention. It will be understood, of course, that the mounting arrangement is identical at both ends of the handle. An first internally threaded opening 94 extends inwardly from mounting surface 20. A thread insert 96 is placed in each opening 94. Inserts 96 are known per se, being of helically coiled construction and of diameter slightly greater than the diameter of the openings into which they are threaded so that they are self-retaining in operation. A second internally threaded opening 98 adjacent to the handle end laterally intersects opening 94 through thread insert 96. Screw 52 extends through limb 24 and is threadably received in insert 96. A set screw 100 is then threaded into opening 98 and tightened against insert 96. In this way, screw 52 is locked in insert 96 without damaging the screw threads. When it is desired to loosen or tighten screw 52 so as to adjust draw force of the bow, set screw 100 is first loosened, screw 52 is adjusted as desired, and set screw 100 is retightened so as to hold the adjustment position.