Composite Archery Bow With Bow Limb Tension Control Device

Abstract

An archery bow is composed of a rigid middle portion having a pair of rotatable members supported at equal distances from the center thereof, a pair of bow arms connected to the rotatable members respectively and extending from the ends of the rigid middle portion, with the bowstring extending between the outer end of the arms, means interconnecting the rotatable members causing them to rotate in unison and in opposite directions for equalizing the movement of the bow arms, and resilient tension means controlling the rotation of the rotatable members and the movement of the arms.

Parent Case Text

This application is a continuation-in-part of application Ser. No. 99,966, filed Dec. 21, 1970, entitled "Archery Bow with Multi-plying Attachments", and since abandoned.

Description

BACKGROUND OT THE INVENTION

With archery bows of various types, and especially with heavy hunting bows, it is possible to produce unequal tension at the two ends of the bow arms to which the bowstring is attached as the bowstring is drawn. In other words, with the drawing of the bowstring it is possible to have one end of the bow move to a greater extent than the other and exert greater tension at that end of the bowstring, temporarily producing an unbalanced bow influencing the accuracy imparted to the arrow. Although many means have been devised for increasing the tension imposed on the bowstring when it is drawn, and thereby increasing the impetus or force with which the arrow is discharged from the bow, it is still possible with these modified bows, as with an ordinary bow, to handle the bow in such manner as to have greater tension produced at one end than at the other end of the bow when the bowstring is drawn and the arrow released. The main object of the present invention is to prevent this possibility and to provide means through which both ends of the bow will move the same distance with the tension exerted at both ends of the bowstring being controlled and equal as the arrow and the center of the bowstring are released.

SUMMARY OF THE INVENTION

The composite bow of the present invention is formed with a rigid middle portion and a pair of bow arms hingedly connected with the respective ends of the middle portion. Tension for the bow, and thus for the bowstring extending between the outer ends of the arms, is provided by equalized cooperating tension-producing means on the inner ends of the arms and on the adjacent end sections of the rigid center portion of the bow. Also, the arms are secured to a pair of wheel-like members respectively which are rotatably mounted on the rigid middle portion and are interconnected by cords or similar flexible means so arranged as to require the wheel-like members, and therewith the arms which are secured to the members, always to move in unison but in opposite directions. Thus, as the bowstring is drawn, causing the outer ends of the bow arms to be pulled inwardly toward each other against the force of their respective tension-producing means, the fact that each arm moves the same distance as the other results in the bow being always in controlled condition.

BRIEF DESCRIPTION OF THE DRAWING

In the drawings:

FIG. 1 is a side elevation of the bow assembly with a portion broken away and shown in section, the normal position of the members of the assembly being shown in full line and the position of these members when the bow is in drawn position being shown in broken lines;

FIG. 2 is a foreshortened, partial elevation taken from the forward side of the bow and a partial section, both taken along the line indicated at 2--2 in FIG. 1, and drawn to a larger scale;

FIG. 3 is a fragmentary sectional elevation taken on the line 3--3 of FIG. 2;

FIG. 4 is a fragmentary elevation of one end of the bow assembly showing a modified means for mounting each of the bow arms;

FIG. 5 is a section taken on line 5--5 of FIG. 4, drawn to a larger scale;

FIG. 6 is a fragmentary elevation on line 6--6 of FIG. 4, drawn to the same scale as FIG. 5;

FIG. 7 is a foreshortened elevation of one of the tension spring members of FIGS. 1 and 4, drawn to a larger scale;

FIG. 8 is a fragmentary side elevation of one end of the bow assembly, similar in part to FIG. 1, but with the addition of toggle linkage between the rigid middle portion and the bow arm, and with the tension spring member connected to the toggle linkage instead of being connected directly to the bow arm, the normal position of the members being shown in full lines and the position of the members when the bow is in drawn position being shown in broken lines; and

FIG. 9 is a fragmentary side elevation of one end of the bow assembly showing the tension spring member mounted at the rear side of the bow and connected by linkage to the respective bow arm.

Referring first to FIGS. 1, 2 and 3, the bow assembly includes a rigid middle portion, designated in general by the reference 10, and a pair of bow arms 11 and 12 hingedly mounted at the opposite ends of the middle portion respectively. The middle portion may be formed of wood, aluminum or other suitable rigid material, and is provided with a channel 13 (see FIG. 2) extending longitudinally along the forward or convex side of the middle portion from one end to the other and at one side of the longitudinal center line. The ends of the middle portion 10 are bifurcated and the inner ends of the bow arms 11 and 12 are hingedly mounted on the stub shafts 14 and 15 respectively which extend through the bifurcated ends. The surface of the middle portion 10 is formed with a transverse contour to provide a comfortable handhold near the center and with the customary alignment groove 16 on one face for the arrow shaft. The ends of the bowstring 17 are attached to the outer ends of the bow arms 11 and 12 respectively, the bow string thus being located on the rear side of the bow assembly as is customary.

The two bow arms 11 and 12 are identical though oppositely mounted. A pair of rotatable or wheel-like members 18 and 19 are secured to, or formed integral with, the inner ends of the arms 11 and 12 respectively and rotate with the arms 11 and 12 on the hinge shafts 14 and 15 extending through the bifurcated ends of the middle portion 10. The rotatable members 18 and 19 are in alignment with the longitudinal channel 13 of the middle portion 10. The peripheries of the rotatable or wheel-like members 18 and 19 are formed with a pair of grooves to accommodate a pair of cords 20 and 21 which extend from the members 18 and 19 in opposite directions and have their ends secured in the members respectively.

Thus the cord 20, having one end secured in a peripheral groove of the member 18 on the bow arm 11, after passing partway around the periphery of the member 18 in clockwise direction (as viewed in FIG. 1), extends from the member 18 along in the channel 13, passing over a guide roller 20' in the channel 13, to the member 19 on the arm 12, and then passes partway around the periphery of the member 19 in counter-clockwise direction (as viewed in FIG. 1). As a result of this cord connection between the rotatable members 18 and 19 and the bow arms to which they are connected, it will be evident that a swing of the arm 11 in counter-clockwise direction (as viewed in FIG. 1) will result in an equal and corresponding swing of the arm 12 in the opposite or clockwise direction. The ends of the cord 20 are secured respectively to the two members 18 and 19 by any suitable means, such as a set screw, one of which is shown at 22 in FIGS. 2 and 3. The cord 20 carries a suitable means, such as a turnbuckle, for adjusting any slack which may develop in the cord.

Similarly a second cord 21, having one end secured on the member 18, passes around the other peripheral groove of the member 18 in counterclockwise direction (as viewed in FIG. 1), extends from member 18 along in the channel 13 and over a guide roller (indicated at 21') and passes around member 19 in counter-clockwise direction, having its other end secured in the corresponding peripheral groove on the member 19. Thus, due to the connecting cord 21, a swing of the arm 11 in clockwise direction (as viewed in FIG. 1) will result in the corresponding equal swing of the arm 12 in the opposite or counter-clockwise direction. This cord 21 similarly carries a turnbuckle for adjusting any slack which may develop in the cord. Consequently the two hinged bow arms 11 and 12 are so connected through their respective members 19 and 19 and the cords 20 and 21 that they move in unison in opposite directions. This is a very important feature in the composite bow assembly.

In order to limit the swinging of the bow arms between the fully-drawn bow position and the normal inactive position, the inner end of each bow arm is formed with a pair of suitably spaced peripheral ears 23 and 24 (FIGS. 1 and 3) which engage a cross pin 25 in the corresponding end section of the middle portion 10 at the limit of the inward and outward swing respectively.

Adjustable tension means is provided for resisting the swinging of the bow arms 11 and 12 inwardly towards each other and thus to provide the desired tension on the bowstring, the tension being applied to the bowstring from the outer ends of the arms 11 and 12. In the composite bow construction as shown in FIG. 1, a pair of resilient tensioning springs 26 and 27 have their inner ends secured to the forward or convex side of the rigid middle portion 10 in the locations shown and extend obliquely forwardly in opposite directions in the same plane with the middle portion and the bow arms. The outer ends of these springs 26 and 27 are each connected by a cord 28, or similar suitable means, to the bow arms 11 or 12. Each of the bow arms 11 and 12 is formed with a slot 29 (FIG. 2)the opposite walls of which have registering holes to accommodate a pin 30 on which the outer end of the cord 28 is secured for connecting the bow arm to its respective control spring. The fact that the position of the cross pin 30 can be adjusted in each bow arm enables the tension on the bow arm to be adjusted accordingly, as desired.

In the modification shown in FIGS. 4, 5 and 6 the rotatable members 31 (FIG. 6) at each end of the rigid middle portion 10 are wider and are formed with an outwardly-extending slotted bracket 32. Each bracket 32 is formed with a saddle 33 near its outer end and the inner end of the corresponding bow arm 34 is secured on the saddle of the slotted bracket.

A cord 36 has one end connected to the outer end of the tension spring for each arm and the other end of the cord 36 is connected to a cross pin 37 extending between a pair of registering holes in the opposite walls of the slot in the bracket 32, the bracket being provided with a plurality of such registering holes to enable the cross pin 37 and cord and spring tension to be adjusted.

In the modified construction shown in FIG. 8, each bow arm 38, like the bow arms of FIG. 1, is pivotally mounted on the hinge shaft with the rotatable member. However, each bow arm is provided with an ear 39 on the rear side, and the corresponding end of the middle portion 10' of the bow assembly in this construction is provided with an ear 40. A pair of toggle links 41 and 42 are pivotally connected to the ears 39 and 40 respectively and are connected to each other by the pivot pin 43. Each bow arm 38 in this construction is slotted, like the bow arms of FIG. 1, but the cord 44 connected to the outer end of each tension spring passes entirely through the slot in the corresponding bow arm and has its end connected to the connection 43 joining the toggle links 41 and 42 instead of being connected directly to the bow arm. By making the toggle links longer the amount of movement of the tension spring with the swing of the bow arms in the drawing of the bow would be increased.

FIG. 9 illustrates a further modification in which the tension spring 45 for each bow arm is mounted on the rear face of the rigid middle portion 10 instead of on the forward face. Each of the bow arms 46, like the bow arms in the construction previously described with reference to FIGS. 1 and 8, is pivoted on a hinge shaft with its rotatable member but the bow arms 46 are not formed with any longitudinal slot. An ear 47 on the rear side of each bow arm 46 provides a pivotal mounting for a link 48, the other end of which is pivotally connected with the outer end of the adjacent tension spring 45.

Other modifications in the construction would be possible without departing from the basic principle of having the bow arms and their spring tension controlled through the medium of the rotatable members mounted on the respective ends of the rigid middle portion and so connected as to move always in unison in opposite directions.

Claims

I claim:

1. A composite archery bow assembly comprising a rigid middle portion, a pair of rotatable members supported on each end of said middle portion respectively, a pair of bow arms fixedly connected to said rotatable members, respectively, and extending from said end sections of said middle portion, a channel extending longitudinally the length of said middle portion, means passing along through said channel and interconnecting said rotatable members for causing said rotatable members to rotate in unison and in opposite directions, whereby to equalize the movements of said rotatable members and therewith of said arms, a bowstring extending between the outer free ends of said arms, tension means connecting said bow arms and said end sections of said middle portion for applying tension to resist the movement of said bow arms inwardly-rearwardly towards each other and said tensioning means further including springs fixedly connected to the respective opposite ends of the middle portion and engaging the bow arms.

2. The archery bow assembly of claim 1 comprising connected rotatable members each connected to one of said tension springs, said tension springs having their inner ends secured to the forward side of said rigid middle portion and extending obliquely forwardly in opposite directions from said middle portion, in the same plane with said middle portion and in opposite direction from said bow arms, and means connecting the outer free ends of said springs with said bow arms respectively.

3. The archery bow assembly of claim 2; with said means connecting the outer free ends of said springs with said bow arms being adjustably secured to said arms.

4. The archery bow assembly of claim 1 with the addition of toggle linkage connecting each of said bow arms with said rigid middle portion located on the rear side of the assembly, said tension assemblies comprising a tension spring for each bow arm, said tension springs having their inner ends secured to the forward side of said rigid middle portion and extending obliquely forwardly in oppo-site directions from said middle portion in the same plane with said middle portion and said bow arms and in opposite directions from said bow arms, joining means connecting the outer free ends of said springs with said toggle linkage respectively and each of said bow arms being provided with a slot enabling said joining means to pass freely therethrough.

5. The archery bow assembly of claim 1 with a radially-extending bracket on each of said rotatable members extending out beyond the end of said rigid middle portion, said bow arms secured to said brackets respectively, and with said tension assemblies each tension spring is connected to a rotatable member and bow arm, said tension springs having their inner ends secured to the forward side of said rigid middle portion and extending obliquely forwardly in opposite directions from said middle portion in the same plane with said middle portion and said bow arms and in opposite direction from said bow arms, and means adjustably connecting the outer free ends of said springs with said brackets.

6. The archery bow assembly of claim 1 with tension spring connected to each bow arm, said tension springs having their inner ends secured to the rear face of said rigid portion and extending obliquely rearward in opposite directions from said middle portion in the same plane with said middle portion and said bow arms, and linkage connecting the outer free ends of said tension springs with said bow arms respectively.