US3814074A - Archery bow with force balancing structure associated with the handgrip - Google Patents

Abstract

A long bow having limbs of substantially identical length and resistance to bending which are joined by a rigid central portion is improved by pivotally mounting a contoured hand grip upon a fulcrum and adapting the hand grip to abut the rigid central portion of the bow when a reaction force is applied to the hand grip. By coordinating the distances between the fulcrum and the abutting part of the hand grip to the distance between the flexing center of the bow, the line of pull for the arrow, the moments about the fulcrum can be balanced while maintaining an equal deflection of the limbs. The distance between the fulcrum and the abutting part can be made adjustable either by making the fulcrum vertically movable along the rigid central portion or by making the abutting part so movable. Also, the deflection of the bow from a vertical orientation can be measured by an arrow shaped member pivotally mounted to the rigid central portion of the bow which is weighted at its free end and which indicates the degree of tilt on a scale formed on the bow and the adjustment of the distance between the fulcrum and the abutting part can be indicated by a scale.

Description

United States Patent [191 Wood 1 1 June 4,1974

[ ARCHERY BOW WITH FORCE BALANCING STRUCTURE ASSOCIATED WITH THE HANDGRIP [76] lnventor: Brian Wood, 13637 Vernon St.,

Hazel Park, Mich. 48237 22 Filed: Apr. 13, 1972 21 App]. No.: 243,662

[52] US. Cl. 124/24 R, 124/30 R [51] Int. Cl F4lb 5/00 [58] Field of Search 124/23, 24, 25, 35, 30 R Primary Examiner-Richard C. Pinkham Assistant Examiner-William R. Browne Attorney, Agent, or Firm-Cushman, Darby & Cushman [57] ABSTRACT A long bow having limbs of substantially identical length and resistance to bending which are joined by a rigid central portion is improved by pivotally mounting a contoured hand grip upon a fulcrum and adapting the hand grip to abut the rigid central portion of the bow when a reaction force is applied to the hand grip. By coordinating the distances between the fulcrum and the abutting part of the hand grip to the dis tance between the flexing center of the bow, the line of pull for the arrow, the moments about the fulcrum can be balanced while maintaining an equal deflection of the limbs. The distance between the fulcrum and the abutting part can be made adjustable either by making the fulcrum vertically movable along the rigid central portion or by making the abutting part so movable. Also, the deflection of the bow from a vertical orientation can be measured by an arrow shaped member pivotally mounted to the rigid central portion of the bow which is weighted at its free end and which indicates the degree of tilt on a scale formed on the bow and the adjustment of the distance between the fulcrum and the abutting part can be indicated by a scale.

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I I72 L 1 ARCHERY BOW WITH FORCE BALANCING STRUCTURE ASSOCIATED WITH THE HANDGRIP BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to archery bows and, in particular, to devices for equal deflection of the limbs when the bow is drawn.

2; Description of the Prior Art In prior art bows, the contoured grip, or portion which is grasped by the bow hand of the archer is generally formed and positioned so that when the bow is drawn the hand of the archer is placed on the bow below the geometric and flexing center of the bow, resulting in rotation of the rigid central portion of the bow in the plane of the bow, about the reaction point of the grip which contacts the archers bow hand. Rotation of the rigid central portion in the plane of the bow causes unequal deflection of the limbs or flexible members of the bow when the bow is drawn.

Attempts have been made by prior'art bowyers to compensate for unequal deflection inthe limbs of their bows by making the lower limb of the bow shorter, or stiffer, or longer and stiffer than the upper limb, thereby causing the lower limb of the bow to resist the increased deflection to which it is subjected, as a result of rotation of the rigid central portion, thereby tending to cause equal deflectionof the limbs when the bow is drawn. See in this regard the patent of Hoyt, U.S. Pat. No. 2,995,130 of August 1961.

Such methods of equalizing limb deflection, however, have provided only a partial solution to problems of instability in prior art bows, since, once the lower limb of the bow is formed differently as compared to the upper, there are always some differences in'deflection, and recovery rate, due to added stiffness or mass, and some consequent inequality in the forces applied to the arrow, when the bowstring is released from the fully drawn position.

Another problem is that prior art bowyers have been able to establish the reaction point on the grip, about which the bow is drawn, and attempt to place the archers hand on-the grip, relative to that point, only in such a manneras they presume will suit the hand of the average archer.

Due, however, to the fact that there are many different shapes and sizes of human hands, and to the fact that no adjustment of the reaction point is provided on prior art bows, many archers do not place their hands on prior art bows to create the reaction point on the bow grip which the prior art bowyer contemplated in his design.

Consequently, many archers unwittingly cause unequal deflection in the drawn limbs of their bows by being unable to place their hands on the bow grip in the intended relationship to the reaction point in the geometry of the bow, and as a result find their bows touchy, which is to say difficult to shoot accurately, especially with regard to obtaining consistent arrow flight in the vertical plane. Experienced archers experiment with hand placement on the bow, often finding that the hand position on the bow which causes it to shoot arrows most consistently is not always the most natural or relaxed position for their particular hand, but attempting to maintain such hand position on the bow, in order to obtain optimum performance from the bow. Unnatural bow hand positions become increasingly difiicult to maintain as the archer tires. Thus, after shooting for any length of time many archers find it difficult to maintain the same degree of accuracy in shooting. Such inaccuracy can in part be attributed to muscular fatigue in the bow hand due to the hand having been forced into an uncomfortable and unnatural position for long periods, by archers seeking to obtain the best possible performance from their bow by such means. Obviously, as the archers bow hand fatigues toward the end of a tournament, slight changes will occur in the relationship of the bow hand to the intended reaction point on the contoured bow grip, resulting in changes in limb deflection and subsequent changes in the forces applied to the arrow by the bowstring upon release from the fully drawn position. The changes described result inchanges in arrow flight, which, in turn, spoil the archers aim.

Another prior art attempt at remedying the problem of unequal limb deflection is embodied in the patent to Mulkey, U.S. Pat. No. 2,714,377 issued on Aug. 2, 1955. The Mulkey device depends for its function upon the rearward rotation of rigid inflexible limb members connected directly to an equalizingdevice.

With the preceding in mind, this instant invention comprises a bow in which the limb members can be made as closely identical as possible with a view to applying nearly identical forces to the arrow on release of the bowstring, with equal deflection of the drawn limbs.

This is caused by separating the contoured hand grip portion from the rigid central portion of a bow and causing the grip to rotate away from the archer by means of a fulcrum on the lower extremity thereof, located on the rigid central portion. By applying the principles of levers, force applied to the grip when the bow is drawn can be magnified, and applied a short distance below the'fulcrum on the lower extremity of the grip, to a reaction pointon the rigid central portion of the bow, in a direction towards the archer to balance any moment tending to rotate the bow in its plane.

A few simple calculations with respect to the forces involved show that by this method and with the proper leverage ratios, the force required to draw the bow can be-used indirectly to maintain the rigid central portion ofthe bow in equilibrium within the plane of the bow, despite the reaction point on the bow grip being located asymmetrically with respect to the bows geometry, and despite closely identical limb members being used and placed symmetrically with respect to the bows geometry. Once the rigid central portion could be maintained in equilibrium, equal deflection of the drawn limb members could be assured, provided the archers hand could be placed in the required position on the contoured grip of the bow.

Exact placement of the archers hand on the grip, rel ative to the reaction point on the grip being impossible due to shape and size differences of archer's hands, and due to different methods of applying the hand to the grip being most natural and comfortable to different individuals, it was found desirable to provide adjustment of the relationship of the fulcrum point on the lower extremity of the grip to the reaction point on the rigid central portion of the bow by increasing or decreasing the distance, from the fulcrum to the reaction point, in order to induce the grip lever to apply to the reaction point the same predetermined force which was required to maintain the rigid member in equilibrium when the bow was drawn despite variations in the length of the grip-lever, caused by hands applied differently to the bow. Obviously, as the length of a lever is increased, the lever will apply the same force at a greater distance from the fulcrum and vice versa.

Having achieved the desired adjustability of the force applied by the grip-lever to the reaction point on the rigid central portion of the bow, it was further found desirable to provide means of determining, for the individual archer,-exactly when the limbs of his drawn bow were in equal deflection, as aresult of his adjustment of the force applied by the grip-lever to the reaction point on the rigid central portion of the bow.

That is to say, the archer should be able to determine when the geometry of the bow had been adjusted to suit the reaction point on the grip provided by his particular hand, applied to the grip in a manner most suitable and comfortable to himself. It was established, therefore,

' that when the rigid central portion of a bow, when fully drawn, was in equilibrium, at 90 to the ground, the drawn limbs would be equally deflected. Having thus established-the position of the rigid section of the bow which provided for equal deflection of the drawn limbs, a simple pointer adapted to pivot freely on the rigid section of the bow, and operate in the manner of a plumb line, or pendulum, with respect to a scale on the rigid portion of the bow was sufficient to determine the angular position of the rigid portion of the bow, with respect to the ground, and the resulting degree of equality of limb deflection.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in detail with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of a bow constructed according to the invention;

FIG. 2 is an enlarged view of the measuring device indicated at 176 in FIG. 1, and a view partially of the corresponding area of the rigid member 3;

FIG. 3 is a side elevation of the area shown in FIG. 2;

FIG. 4 is a schematic drawing, illustrating the problems inherent with modern bow geometry, and the principles of operation of the pivoted grip in providing a counter rotational force to the rigid member, thereby preventing rotation of the rigid member in the vertical plane, when the bow is drawn;

FIG. 4A is a force diagram showing the forces distributed by the bow shown in FIG. 1;

FIG. 5 is a rear elevation of the grip area of an embodiment of the bow of the invention as it faces the archer;

FIG. 6 is a view in section takenalong the line 6-6 in FIG. 5;

FIG. 7 is a partial, much enlarged view of the area indicated at 6a and 6b in FIG. 10, for the purpose of clarification thereof;

FIG. 8 is a drawing of the pin 11 shown in FIG. 6, provided for the purpose of more clearly illustrating the form thereof;

FIG. 9 is an end view of the pin 11 shown in FIG. 8;

FIG. 10 is a view in section, taken along the line 10-10 in FIG. 6;

FIG. 11 is a rear view of another embodiment of the bow of the invention showing thegrip area as it faces toward the archer;

FIG. 12 is a side elevation of the grip area shown in FIG. 11;

FIG. 13 is a partial view in section taken along the line 13-13 in FIG. 11; 1

FIG. 14 is a partial view in section taken along the line 14-14 in FIG. 11;

FIG. 15 is a view in section taken along the line 15-15 in FIG. 12;

' FIG. 16 is a partial front elevation taken along the line 16-16 in FIG. 12;

FIG. 17 is a rear view of another embodiment of the bow of the invention showing the grip area as it faces toward the archer;

FIG. 18 is a view in section taken along the line 18-18 in FIG. 17; I

FIG. 19 is a partial view, much enlarged of the area indicated as 6b in FIG. 17, for the purpose of clearly illustrating the relationship of the insert 72 to the adjustment screw 8a;

FIG. 20 is a rear view of another embodiment of the bow of the invention showing the grip area as it faces the archer;

FIG. 21 is a view in section taken along the line 21-21 in FIG. 20;

FIG. 22 is a'partial front elevation taken along the line 22-22 in FIG. 21;

FIG. 23 is a view in section taken along the line 23-23 in FIGS. 21 and 25;

FIG. 24 is a rear view of another embodiment of the bow of the invention showing the grip area as it faces toward the archer;

FIG. 25 is a side elevation of the grip area shown in FIG. 24;

FIG. 26 is a partial front elevation taken along the line 26-26 in FIG. 25;

FIG. 27 is a view in section taken along the line 27-27 in FIG. 25;

FIG. 28 is a rear elevation of the functioning area of another embodiment of the bow of the invention, as it faces the archer the remainder of the bow being constructed in a similar fashion to those shown in FIGS. 1, l7 and 18;

FIG. 29 is a side elevation of the area shown in FIG. 28;

FIG. 30 is a rear elevation of the functioning area of another embodiment of the bow of the invention, as it faces the archer, the remainder of the bow being constructed in a similar fashion to those shown in FIGS. 1, I1 and 12;

FIG. 31 is a view in section taken along the line 31-31 in FIG. 30;

FIG. 32 is a view in section taken along the line 32-32 in FIG. 31;

FIG. 33 is a rear elevation of the functioning area of another embodiment of the bow of the invention, as it faces the archer, the remainder of the bow being constructed in a similar fashion to those shown in FIGS. 1, 20 and 21;

FIG. 34 is a view in section taken along the line 34-34 in FIG. 33;

FIG. 35 is a rear elevation of the functioning area of yet another embodiment of the bow of the invention as it faces the archer, the remainder of the bow being constructed in a similar fashion to those shown in FIGS. 1, and 21;

FIG. 36 is a view in section taken along the line 36--36 in FIG. 35;

FIG. 37 is a rear elevation of the grip area of the final embodiment of the bow of the invention, as it faces toward the archer;

FIG. 38 is a view in section, taken along the line 38--38 in FIG. 37;

FIG. 39 is a view in section, taken along the line 39-39 in FIG. 37; and

FIG. 40 is a view in section, taken along the line 40-40 in FIG. 38,

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, the terms forward, fore" or foremost" shall be deemed to refer to a direction away from the archer, toward the target, as he stands, facing the target in a normal shooting position. The terms rear or rearward shall be deemed to refer to a direction toward the archer in a direction away from the target as he stands in the normal shooting position; and the term plane of the bow is the plane running through the axes of the bow and the drawstring thereof.

In order that the principles of the device of the invention may be clearly understood, a brief explanation will 'be given with reference to the schematic drawing shown in FIG. 4 and force diagram 4A.

In a bow, constructed as shown in FIG. 4, in which the limbs 2a and 2b are mounted equidistant from the geometric and flexing center G of the bow, vertically, as shown by A dimension in FIG. 4, and in which the limbs 2a and 2b are matched as closely as possible with regard to length, contour, and stiffness, or resistance to bending, equal deflection of the drawn limbs 2a and 2b, is impossible since the reaction point R about which the bow is drawn, and upon which the archers bow hand rests, is located substantially below the geometric and flexing center G of the bow, which represents the line of force applied by the archer when drawing the bow. As is well known to those skilled in the art, a bow constructed as described will not function properly, since, if thegrip 5 is integral with the rigid central portion 3, when force is applied to the bowstring 1, and the reaction point R in order to draw the bow, the rigid section 3 rotates in the plane of the bow to the approximate position shown by the dotted outline in FIG. 4 and the limbs 2a and 2b are, as a result, unequally deflected to the approximate position shown by the dotted outline in FIG. 4. Unequal deflection of the limbs 2a and 2b results in unequal forces being applied to the arrow when the bowstring l is released from the fully drawn position. The resulting erratic arrow flight, and eventual breakdown of the lower limb 2b, due to continual excessive deflection, are also well known and recognized as being extrememly undesirable by those skilled in the art.

If, however, according to the present invention the grip area 5, is separated from the rigid section 3, and allowed to pivot about a fulcrum L, on the rigid section 3, the sum of the force required to draw the bow,

normally applied at the reaction point R, may be transmitt'ed in the manner of a lever to the reaction point K on the rigid section 3. Further, if the fulcrum L on the lower extremity of the grip 5, and the reaction point K, are appropriately arranged with respect to the geometry of the bow, sufficient force may be applied by the grip-lever to maintain the rigid portion 3 in equilibrium in the plane of the how, when the bow is drawn, thereby ensuring the appropriate bow geometry and equal deflection of the drawn limbs 2a and 2b.

In FIG. 4 the forces F, applied by the limbs 2a and 2b to the rigid section 3 when the bow is drawn, are shown as acting parallel to the geometric and flexing center G. It is well understood that the direction of these forces is not necessarily as shown in FIG. 4. But since the limb members are construed as applying identical forces, in identical directions, and since the geometry of the bow is arranged so that if the rigid section 3, were supported at point N on line G closest to the bowstring, the rigid section would remain in equilibrium when the bow was drawn, the complex calculations required to determine the direction of forces F and the resulting effect on the structure are disregarded, it being sufficient that the forces applied by the limbs 2a and 2b maintain the structure in equilibrium when the drawn bow is supported at point N on line G in FIG. 4, to allow the assignment of the arbitrary direction, parallel to line 0" to the forces F". Further, in the preferred embodiments of the invention, a sufficiently wide range of adjustment is provided for the relationship of fulcrum L to reaction point K, so that the ratio of leverage, and thereby the forces applied at K can be so varied as to compensate for such minor errors in required grip-leverage ratio as may be made, due to the directions of forces F and to the weight of the bow structure acting vertically downward, being disregarded.

With the preceding in mind, it is obvious that the calculations required to prove the principle of operation of the devide are greatly simplified, without being based on false premises.

Therefore, in ,FIG. 4 if A IO inches, E 2 inches, and Z 5 inches, then B 15 inches, C 5 inches and X 3 inches and if the force required, at point 0 on the bowstring to hold the string drawn be 40 pounds then F 4012 20 pounds (since both limbs are construed as producing equal forces) and the force at point R will equal 40 pounds. Taking moments about the fulcrum L, with the bow supported at R and the grip pivoting as described, the moments of the forces produced by the drawn limbs are as follows: counter clockwise, F X8 20 X 15 300 pounds/inch; and clockwise F X C 20 X 5 pounds/inch. Subtracting the limb moments it is obvious that a counter clockwise rotational force of 200 pounds/inch is supplied by the upper limb. For equilibriumof the rigid member when the bow is drawn, it is obvious that a balancing force must be ap plied at reaction point K in the magnitude of 200 pounds/inch.

Therefore, taking moments of the grip lever about fulcrum L, for equilibrium of the rigid member in the drawn bow, and subsequent equal deflection of the drawn limbs, R X X 40 X 3 200 X Y. Therefore, Y l 2 0/200= 0.6 or 6/10 inches. It is established by the above that if the reaction point K" is established at a point 0.6 or 6/10 inches below the fulcrum L" the grip lever will supply a force of 200 pounds/inch at reaction point K, when the bow is drawn, thereby balancing the counter clockwise rotational force applied by the upper limb 2, to the rigid portion, and preserving the rigid portion of the bow in equilibrium, and allowing the desired equal deflection of the limbs 2, see FIG. 4A in this regard.

. Further, if dimension E in FIG. 4 is increased to 3 inches, due to the reaction point at which force R is applied, R being moved downward on the contoured grip by means of the archers bowhand being applied to the grip in a manner not suited to the geometry of the bow, similar calculations will establish that the reaction point K must be located at a point 0.4 or 4/10 inches below fulcrum point L in order for the required balancing force of 200 pounds/inch to be applied at reaction point K.

It will be clear, therefore, that adjustment of the relationship of the fulcrum L to the reaction point K must be provided in order to allow archers to adjust the grip-leverage ratio to suit their particular hand, applied to the bow in a manner best suited to themselves.

It is appreciated that the calculations applied to the solution of the grip-lever problem are approximate in nature but it is believed that they are sufficiently accurate to establish a functional geometry for the bow of the invention, and to prove that the grip-lever principle will perform its intended function of preserving the rigid member of the bow in equilibrium, when the bow is drawn, if the appropriate bow geometry is established.

' Further, as previously stated, the preferred embodiments of the invention provide for a sufficiently wide range of adjustment of the Y" dimension in FIG. 4, to not only compensate for movement of the reaction point R by application of different hands to the bow, but also to allow compensation for errors made due to the approximate nature of the calculations applied to the problem.

FIGS. 5 and 6 show the general area of the preferred bow to which the device of the invention is applied, in a greatly enlarged form for purposes of clarity. The area shown corresponds to the encircled area in FIG. 1, the remainder of the bow being constructed generally as shown in FIG. 1, and the geometry of the bow being generally as shown in FIG. 4.

As shown in FIGS. 5 and 6 the rigid central portion of the bow 3 and the contoured grip 5 are two separate, suitably formed items. The rigid portion 3 is of substantially flat, plate like construction, being formed into an offset at its upper extremity 3' to provide the conventional sight window for the bow, and having a thicker, substantially rectangular section 25, extending fora short distance at its lower extremity. The centrally disposed rectangular aperture 16, extends completely through the rectangular section 25, for approximately two thirds of its length, and a little over halfway through the rectangular section for the remainder of its Iength,as shown in FIG. 6.

The separate contoured grip 5 is adapted to enclose a substantial area of the rigid member 3, by means of the aperture 27 formed therein, the forward extremity of the grip 5 being shown by the dotted line 31, in FIG. 6. The aperture 27 in the grip 5 is so formed as to allow the grip 5 to fit around the rigid member 3, but at no point does the inner surface of the grip 5 contact the rigid member 3.

In FIG. 5, the vertically disposed rib or protuberance indicated at 30 is shown to be approximately centrally located with respect to the grip 5, the rib 30 is also shown in FIG. 6, again it will be noted that the clearance aperture 27, does not allow contact between the 8 rib 30 and the surface of the rigid member 3. The rib 30 is provided for the twofold purpose of strengthening the grip 5, and allowing at its lower extremity for the mounting of the fulcrum plate 9, as indicated at 28 in FIG. 6.

The fulcrum plate 9 is vertically disposed within the rectangular aperture 16, in such a manner that at no point does it contact the rigid mamber 3 within the aperture l6.

As shown in FIG. 6, the fulcrum' plate 9 is of approximate L" shape, the wider portion thereof being disposed at the upper extremity, and the narrower leg portion being at the lower extremity.

The fulcrum plate 9 is rigidly secured to the lower extremity of the rib 30, at 28, by means of three screws, 10a, 10b and extending through horizontally disposed circular apertures formed therein, and into threaded apertures in the-fulcrum plate 9. The fulcrum plate 9 is adapted to pivot on the conically formed tips 6a and 6b of the adjustment screws 8a and 8b, respectively, which extend horizontally within threaded apertures formed in the rectangular section 25 of the rigid member 3, as shown in FIG. 5 at 6 and in FIG. 7

. in enlarged form and which therefor form the fulcrum Retention of the fulcrum plate 9 in a predetermined desired position, is assured by means of entry of the conically formed tips 6a and 6b of the adjustment screws 8a and 8b, respectively, into conically formed apertures in the fulcrum plate 9 as shown in FIG. 7, rotation in the vertical plane of the bow being the only subsequent movement permitted thereof. By means of rotation of the adjustment screws 8a and 8b, the fulcrum plate 9 may be centralized in the clearance aperture l6, and the clearance aperture 27 in the attached grip 5, may be centralized about the rigid member 3, thereby ensuring that contact does not occur between either the inner surfaces of the grip 5, or the fulcrum plate 9, and the rigid member 3. The adjustment of the conical tips 6a and 6b of the adjustment screws 8a and 8b is also desirable so that variations in the depth of the conical apertures, formed in the fulcrum plate 9, due to manufacturing tolerances, may be compensated for by adjustment of the screws 8 a and 8b. It being understood that while the fulcrum plate 9 is permitted to pivot freely on the conical tips 6a and 6b of the adjustment screws 8a and 8b, maximum surface contact is required between the conical tips 6a and 6b of the adjustment screws 8a and 8b and the surfaces of the conical apertures, formed in the fulcrum plate 9, so that an absolute minimum of side to side movement is permitted on the part of the fulcrum plate 9, and the attached grip 5. Once the adjustment screws 8a and 8b are adjusted to the desired position, they may be locked by means of tightening the-locking nuts 7a and 7b, respectively, which are adapted to bear against the flat surfaces 26a and 26b of circular bosses which are integrally formed with the rectangular section 25 of the rigid member 3.

When force is applied, by the archer, in the act of drawing the bow, to the grip 5, at the approximate point indicated by the arrow R in FIG. 6, the grip 5 and the attached fulcrum plate 9 rotate in the plane of the bow until the flat surface 18 of the fulcrum plate 9 contacts the curving surface formed on the pin 11, at reaction point K. A reaction point for the grip-lever is thereby established, integrally with the rigid member 3.

The pin 11 is disposed at a slight angle to the vertical, for manufacturing purposes, and is adapted to slide freely within the circular bore 29 formed in the rigid member 3. As shown in FIGS. 8 and 9, the pin 11 is of substantially circular contour, having formed thereon the curving area 32 and the flat clearance area 19 toward the upper extremity and the reduced threaded portion 21 at the lower extremity. The end view of the pin 1 1, shown in FIG. 9, illustrates that the curving area 32 in FIG. 8 is transversely formed so as to provide a straight portion 33 lying in the same plane as point K, and parallel to the flat clearance area 19.

Approximately vertical adjustment of the pin 11 is provided by means of the adjustment nut 12 which is in threaded engagement with the threaded portion 21 of-the pin 11, and in sliding .frictional engagement with the surfaces of the slot 22 which extends transversely through the rigid member 3. As shown in FIG. 5, the adjustment nut 12 is large enough in diameter to protrude on either side of the rigid member 3, sufficiently so that said outside diameter, which may be knurled or similarly roughened, can be gripped by the fingers for purposes of rotation thereof. Since the nut 12 is frictionally entrapped within the slot 22, rotation of the nut 12 causes linear motion of the threaded portion 21 of the pin 11 and consequently the entire pin 11 within the aperture 29. Rotation of the pin 11 is prevented by engagement of the straight area 33 at point K, with the flat portion 18 of the fulcrum plate 9. The flat clearance area 19 is provided to allow contact of the flat area 18 of the fulcrum plate 9 at point K on the pin 11 only. The pin 11 may be freed for motion within the aperture 29, or locked in position after adjustment by loosening or tightening the set screw 13 which is in threaded engagement with the horizontally disposed threaded aperture 34 which extends through the wall of the rectangular section 25 of the rigid member 3, and into the circular aperture 29. The reduced circular aperture 20 is a vertical extension of the circular aperture 29, and is provided in sufficient depth to allow the maximum downward adjustment necessary to the lowest extremity of the reduced threaded portion 21 of the circular pin 11.

The resilient pads 23 and 24a and 24b, shown in FIG. 6 which are inserted in the clearance apertures 16 and 27, between the inner surface of the grip 5, and the rigid member 3, and between the lower forward extremity of the fulcrum plate 9, and the inner surface of the cover plate 14, are designed in the case of the pads 24a and 24b to offer the minimum resistance to rotation of the grip 5, whilst preventing rattling or vibration of the grip 5, due to shock or vibration transmitted to the area by the limbs of the bow, in the act of discharging an arrow, and in the case of the pad 23, to offer the maximum resistance to rotation of the fulcrum plate 9, in order to prevent excessive rearward rotation of the grip 5, and vibration between the pin 11 and the fulcrum plate 9, at the contact point K.

The cover plate 14 is provided for decorative purposes to conceal the aperture 16 in the rigid member 3, and to provide an inner surface against which the resilient pad 23 may bear. The pad 23 may be glued or similarly bonded to the appropriate surface of the cover plate 14 before said cover is fastened to the rigid member 3, by means of the screws 15 which extend through circular apertures formed therein, and into threaded apertures formed in the rigid member 3. In a like manner, the pads 24a and 24b may be suitably affixed to the appropriate surface of either the grip 5 or the rigid member 3.

It will be obvious from the above, that by means of the device described, the force applied to the grip by the archers hand, when the bow is drawn, is applied in a reversed direction, to an adjustable reaction point, integral with the rigid central portion of the bow. It being simply a question of providing the correct dimensional relationship between the interacting components of the device to ensure that the force applied to the reaction point on the rigid central portion of the bow is of the correct magnitude to balance the counterclockwise rotational force applied to the rigid member, when the bow is drawn, by the upper limb of the bow, thereby maintaining the rigid central portion in equilibrium, and providing for equal deflection of the identical limb members of the bow. Thus, the primary object of the invention is achieved. It will also be obvious that adjustment is provided for the reaction point integral with the rigid member, to compensate for changes in the location of the point about which the bow is drawn, which may be caused by changes, either in the form or the manner of application, of archers hands to the bow. Thus, another object of the invention is achieved.

FIGS. 11 through 16 illustrate another embodiment of the invention. As in the previous embodiment, the device is shown in greatly enlarged form for clarity, and corresponds to the encircled area in FIG. 1. The remainder of the bow being constructed generally as shown in FIG. 4. In fact, in all of the embodiments to be hereinafter described, those portions of the bows which are not shown or described may be construed as being similar in form and geometry to the complete bows shown in FIGS. 1 and 4. Thus, for example, the reference numeral 3 will be used throughout to desig nate the rigid member while the reference numeral 5 will be used throughout to describe the hand grip portion.

As shown in FIGS. 11 through 16, the functioning components of the second embodiment are located at the lower extremity of the grip 5. The grip 5 is adapted for rotation in the vertical plane of the bow by means of the fulcrum pin 43 which forms a fulcrum L about the axis of the pin. FIGS. 11 and 13 show the V-shaped aperture 36 which is centrally disposed with respect to the rectangular section 25 of the rigid member 3, and extends approximately half way through section 25 as shown in FIG. 13. The tenon 35, formed integrally with the lower extremity of the grip 5, extends in an angular direction into the aperture 36, the sides thereof being in sliding frictional engagement with the outer extremities of the aperture 36, as indicated at 38a and 38b in FIG. 11, said frictional engagement being sufficiently close to allow the minimum of side to side movement of the tenon within the aperture 36, while permitting said tenon to slide or rotate freely in the vertical plane of the bow.

As shown in FIGS. 11 and 13 there is a bushing 37 pressed into a circular aperture formed in the lower extremity of the tenon 35, in sufliciently close frictional engagement to prevent rotation or movement thereof. In FIG. 11 it can be seen that the bushing 37 is shorter in length than the tenon 35 is wide, thereby allowing both lengthwise extremities of the bushing 37 to be beneath the outer surfaces of the tenon 35, thereby avoidalloy steel in order to minimize wear due to repeated rotation of the grip with respect to the rigid member 3.

Two lugs 41a and 41b formed integrally with the lower extremity of the grip 5, extend vertically on either side of the rectangular section 25, of the rigid member 3, the inner surfaces of'said lugs being in sliding frictional engagement with the outer surfaces of the rectangular section 25, as indicated at 39a and 39b in FIGS. 11 and 15.

Rectangular bosses 42a and 42b protrude from the outer surfaces of the rectangular section 25 on either side of the rigid member 3, and are formed integrally therewith. In FIG. 12, the vertically disposed wear strips 44a and 45b can be seen, attached by means of the horizontally disposed pins. 46a, 46b and 460 to the flat surfaces 61 and 62 formed on the lugs 41 and the rectangular bosses 42a and 42b, respectively. Frictional engagement of the horizontally disposed pins 46a, 46b,

and 460 within the circular apertures formed in the lugs 41a and 41b the bosses 42a and 42b and the wear strips 44a and 44b and 45a and 45b is sufficiently close to prevent disengagement of the pins 46a, 46b and 460.

Force, applied by the archers bowhand at the point on grip 5 indicated by the arrow R in FIG. 12, causes rotation of the grip 5, the integral tenon 35, and the integral lugs 41a and 41b about the fulcrum pin 43, and subsequent pincer-like entrapment of the reaction pins 40a and 40b between the inner surfaces of the wear strips 44a and 44b and 45a and 45b. The reaction pins 40a and 40b are horizontally disposed with respect to the vertical plane of the bow, on either side of the rigid member 3, as shown in FIG. 11, but the inner extremities of the pins 40a and 40b do not contact the outer surfaces 39a and 39b of the rectangular section 25 as FIGS. 14 and 15 clearly illustrate.

The pins 40a and 40b are held in a predetermined fixed-adjustable position in the vertical plane by means of frictional entrapment in circular apertures formed in the arms 60d and 60b of the U shaped yoke member 58. The yoke member 58 is itself held in a fixedadjustable position in the vertical plane by means of the threaded thumb screw 50 which is in threaded engagement with the vertically disposed threaded aperture formed in the yoke 58.

The thumb screw 50 consists of a circular head which may be knurled on the outside diameter, a reduced, threaded portion 48, and a further reduced, plain portion 54, in which an annular groove 52 is formed, see FIG. 16. The threaded portion 48 of the thumb screw 50 is rotatably secured within the threaded aperture in the yoke 58 by means of the smaller knurled thumb screw 49 which is horizontally disposed within another threaded aperture in the yoke 58, and is adapted to bear against the outside diameter of the threaded portion 48 of the thumb screw 50 when tightened, see FIGS. 13 and 15.

The small thumb screw 49 is formed from softer material than the thumb screw 50, so that damage to the threaded portion 48 of the screw will not occur when the thumb screw 49 is tightened against it. A block 56, is secured to flat surfaces 63, formed on the grip 5 at the upper extremities of the lugs 41, see FIG. 13. As shown in FIG. 16, the block 56 is horizontally disposed and is rigidly secured to the grip 5 by means of the screws 57, which FIG. 12 shows to be extending through circular apertures formed in the block 56, and into threaded apertures formed in the grip 5.

The plain reduced portion 54, of the thumb screw 50 is secured in rotatable frictional engagement with the circular aperture 64 formed in the block 56, by means of the horizontally extending pin 53, shown in dotted outline in FIG. 13, which is frictionally entrapped within a suitably formed horizontally disposed circular aperture in the block 56.

FIG. 16 illustrates the fact that the pin 53 is so disposed that the outside diameter thereof is in tangential relationship to the circular inner extremity of the annular groove 52, formed in the reduced portion 54 of the thumb screw 50. This is a device which is well known in mechanical engineering and provides for the rotation of the end portion 54 of the thumb screw 50, whilst vertical motion thereof is prevented. Dual pins 55a and 55b extend vertically downward from the block 56, and into sliding frictional engagement with the vertically disposed circular apertures formed in the yoke 58, being designed to guide vertical adjustment, and prevent horizontal rotation thereof. The pins 55a and 55b are in frictional engagement with vertical circular apertures formed in the block 56, said engagement within the block 56being sufficiently close to prevent vertical movement of the pins 55a and 55b with respect to the block 56. 7

As shown in FIG. 16, if the knurled screw 49 is loosened, and the thumb screw 50 rotated, the yoke 58 will slide vertically on the pins 55a and 55b, the uppermost possible position of the yoke 58 being shown by the dotted outline 59 thereof. When the yoke 58 is in the desired position vertically, it may be locked in that position by simply tightening the knurled screw 49, and preventing further rotation .of the screw 50. Obviously, as the yoke 58 is adjusted vertically, the reaction pins 40a and 40b which are entrapped in the apertures in the arms 60 of the yoke 58, are carried with the yoke 58 to its new vertical position. Equally obviously the adjustment vertically of the yoke 58 must be carried out while no force is applied to the point indicated by the arrow R on the grip 5, in FIG. 12, so that the reaction pins 40a and 40b are not entrapped by the pincerlike grip of the wear strips 44a and 44b and 45a and 45b and verticalmovement of the pins 40a and 40b is not restricted.

From a study of the above with reference to FIGS. 11 through 16 of the accompanying drawings, it will be clear that the embodiment described achieves the desired objects of the invention with the exception of the measuring device to be later described.

FIGS. 17 through 19 illustrate another embodiment of the invention similar to that shown in FIGS. 5 and 6, in that the grip 5 is adapted to pivot about conically formed tips of adjusting screws, which tips are seated within conically formed apertures integral with rigid member 3 to form a fulcrum L.

The construction of the grip is similar to the grip shown in FIGS. 11 through 15 with the exception that the centrally disposed tenon 35 at the lower extremity of the grip 5 is no longer present, nor is the centrally disposed rectangular section 25, containing the V- shaped aperture 36.

The horizontally disposed insert 72, shown in FIG. 17 is in sliding frictional engagement with the-circular aperture 74 formed in the rigid member 3. The general form of the insert 72 is cylindrical, but rotation thereof is prevented by means of the pin 68 which is disposed at ninety degress thereto, as more clearly shown in FIG. 18, and which is adapted to engage the semi-circular aperture 73 which is formed in the insert 72 as is more clearly shown in FIG. 19.

As indicated at 6a and 6b in FIG. 17 and more clearly shown in FIG. 19 conical apertures are formed in the ends of the cylindrical insert 72, for the purpose of seating the conically formed tips of the adjustment screws 8a and 8b. The insert 72 may be formed of alloy steel, or similar material, in. order to resist Wear which may be caused by constant rotation of the conically formed tips of the adjustment screws 8 within the conical apertures formed in the insert 72. The adjustment screws 80 and 8b are in threaded engagement with horizontally disposed threaded apertures formed in the lugs 41a and 41b of the grip 5. Adjustment of the screws 8 is required for the same reasons given with respect to the embodiment shown in FIGS. 5 and 6. Once adjusted to the desired position, the screws 8 may be locked in position by means of the lock nuts 7a and 7b which are adapted to bear against the flat faces 26a and 26b of the circular bosses formed integrally with the lugs 41a and 41b of the grip 5.

As shown in FIG. 17, by means of vertical extension of the clearance aperture 27 in the grip 5, the inner extremities of the lugs 41a and 41b do not contact either the rigid member 3 or the outer surfaces of the plates 67a and 67b. Force, applied by the archers bow hand to the point on the grip 5 indicated by the arrow R, causes the grip 5 to rotate about the fulcrum L provided by entry of the conical tips of the screws 8a and 8b into the conical apertures formed in the insert 72, causing the inserts 45a and 45b which are formed of wear resistance material to bear against the reaction pin 65. The inserts 45a and 45b are affixed to the flat surfaces 61 formed on the lower extremities of the lugs 41a and 41b by means of the pins 47a and 47b which are frictionally entrapped within suitable circular apertures formed in the inserts 45a and 45b and the lugs 41a and 41b.

The reaction pin 65 is of circular form, consisting of acentrally disposed body 75, and two slightly reduced ends 76a and 76b. The reaction pin 65 is horizontally disposed within the aperture 71 which is vertically disposed with respect to the rigid member 3, and extends completely therethrough.

The vertically disposed slot 71 is adapted to allow the body 75, of the pin 6, and the threaded portions of the screws 66a and 66b to pass freely therethrough and to move freely in a vertical direction within the aperture provided by the slot 71. Vertically disposed plates 67a and 67b formed of alloy steel or similar material, are seated within recesses 70a and 70b formed in the rigid member 3 and are adapted to slide freely in a vertical direction within the outer extremities 77b of the recesses 70. In FIG. 17 it can be seen that the pin 65 is retained in a horizontal direction since the reduced diameters 76a and 76b are in close sliding engagement with circular apertures formed in the plates 67a and 67b, the apertures being smaller in diameter than the body of the pin 75, and not adapted to permit passage of the body 75, of the pin 65 in a horizontal direction.

In FIG. 17, the horizontally disposed screws 66a and 66b can be seen, each screw passing through a circular aperture in one of the plates 67a and 67b, and through the vertically disposed slot 71 into a threaded aperture, formed in the other plate 67a or 67b, so that as FIG. 17 shows each of the plates 67a and 67b contains one plain circular aperture, and one threaded circular aperture. Obviously, when the screws 66a and 66b are tightened, the plates 67a and 67b are clamped against the inner surfaces of the recesses 70, and remain rigidly fixed in the vertical plane. If the screws 66a and 66b are loosened, manual adjustment of the plates 67a and 67b is possible by sliding them in a vertical direction. Vertical adjustment of the plates 67a and 67b and the integral pin 65 is measured by comparison of the line 78 marked on one of the plates 67, to the scale 79, marked on the rigid member 3, as shown in FIG. 18. it will be readily appreciated that this or a similar method of measuring fulcrum to reaction point adjustment could be readily adapted to any of the embodiments of the invention described herein which provide for said adjut ment, and need not necessarily be confined to the present embodiment.

Rattling, and excessive rotation of the grip 5 toward the archer is prevented by means of the resilient pads 24a and 24b and 33, and the block 80. As illustrated in FIGS. 17, 18 and FIG. 23 (which is drawn to another embodiment but which is also relevant to the instant embodiment,) the block 80 is u"-shaped, and provides two flat surfaces 81a and 81b which bear against similar fiat surfaces on the forward extremity of the grip 5. The block 80 is secured to the grip 5 by means of the screws 57a and 57b which extend horizontally through circular apertures formed in the block 80 and into threaded apertures formed in the grip 5. As shown in FIGS. 17 and 18 the resilient pads 24a, 24b and 33 are inserted between the rigid member 3 and the inner surface of the grip 5 and between the outer surface of the rigid member 3 and the inner surface of the block 80. The resilient pads 24 and 33 may be glued or bonded to the grip 5, therigid member 3 or the block 80 or seated within suitable recesses formed in the block 80, the grip 5 or the rigid member 3. As previously stated the resilient pads 24 are designed to offer the minimum resistance to rotation of the grip 5 whilst preventing rattling due to vibration when the bow is in' use. The form of the block 80 is clearly shown in FIG. 23 and is identical thereto.

FIGS. 20 through 27 illustrate embodiments of the invention in which,-whilst equal limb deflection is provided for there is no adjustment of the grip-leverage ratio. It is anticipated that these embodiments may be employed in bows designed for hunting, or in less expensive bows in which precision adjustment of the performance of the bow is not required.

Once again, the functioning area of the device is at the lower extremity of the grip 5.

The vertically disposed aperture, 82 shown in FIG. 21 extends approximately halfway through the rigid member 3 in a forward direction for approximately half of its length, at the upper portion of the aperture, and

the rest of the way through the rigid member 3 at the lower portion. The aperture 82 is centrally disposed with regard to the width thereof with respect to the thicker, rectangular section 25 of the rigid member 3 as shown in FIG. 20. Raised pads 83a and 8312 are formed within the aperture 82 towards the upper and lower extremities thereof. The inner surfaces of the pads 83a and 83b and 87a and 87b are adapted to bear against the outer flat surfaces of the tenon or lug 85 which is formed integrally with the lower extremity of the grip 5, and extends into the aperture 82. The surfaces of the pads 83a and 83b and 87a and 871) are adapted to bear against the flat surfaces of the tenon 85 on both sides thereof as indicated at 92a and 92b in FIGS. and 22 and provide a sliding frictional engagement between the respective surfaces of sufficiently close nature to prevent side to side motion of the tenon 85 within the aperture 82, thereby maintaining the lower extremity of the grip 5 in a fixed position in the horizontal plane of the bow. A similar function is performed by the bosses 89a and 89b and 90a and 9012 which are integrally formed with the surfaces of the clearance aperture 27 in the grip.5 and with the outer surfaces of the rigid member 3, toward the upper extremity of the grip 5, as shown in FIGS. 20 and 21. As indicated at 91a and 91b in FIG. 20 the flat surfaces of the respective bosses are adapted to bear against each other in sliding frictional engagement which is sufficiently close to prevent side to side motion of the upper extremity of the grip 5 in the horizontal plane of the bow. It will beappreciated that similar bosses for similar purposes could be provided in suitable areas in any of the embodiments of the invention described herein, and need not necessarily be restricted to the present embodiment.

In FIG. 21 it can be seen that the forward upper extremity of the aperture 82 is formed into a curving contour which is adapted to allow contact between the flat forward surface of the tenon 85 and the inner curving surface of the'aperture 82 only at the point indicated as 86. Thus, is the fulcrum point L provided for the grip 5.

Similarly, it will be noted that the curving rear lower extremity of the tenon 85 is adapted to contact the flat rearmost surface of the lower portion of the aperture 82 only at-a point indicated as 94. Thus, is the reaction point K provided for the grip-lever. When force is applied at the point indicated by the arrow R in FIG. 2i the grip 5 rotates in a forward direction in the plane of the bow, and transfers the force applied at the point indicated by the arrow R in a magnified form to the reaction point K, via the fulcrum point L.

Downward vertical motion of the grip 5 is restricted by means of the curving lower extremity of the tenon 85 contacting the horizontal, flat lower surface 88 of the aperture 82 at the point indicated as 93 in FIGS. 21 and 22. Upward vertical motion is restricted by the resilient pad 33 seated on the previously described block 80, which is affixed to the grip 5 in such a manner as to cause the resilient pad 33 to bear against the flat, angular foremost surface of the rigid member 3. The relationship described being clearly illustrated in FIGS. 21 and 23. It will be appreciated from a study of the drawings that since the pad 33 is adapted to resist rearward rotation and vertical motion of the grip, it may be formed from material which is only slightly resilient in order to offer greater resistance to said motions, without affecting the vital forward rotation of the grips 5, except perhapsto the point of assisting said forward r0- tation.

It will be readily appreciated by those skilled in the art that the deflection of the limbs of the bow of the present embodiment will only be approximately equal due to form variations of hands which will be applied to the grip. But the present embodiment provides an improved bow, since identical limb members may be used in the construction of the bow. The archer will benefit from the provision of such a bow, since more nearly identical forces will be applied to the arrows by the identical limb members. Further it may be possible to reduce the purchase price of such a bow, since identical limb members are not so difficult to construct as prior art limbs, and consequently manufacturing costs may be reduced, which reduction may in turn be passed to the archer in the form of reduced purchase price.

FIGS. 24 through 27 illustrate another embodiment similar to that shown in FIGS. 20 through 23 in that the relationship between the fulcrum and the reaction point is non-adjustable.

FIGS. 24 and 25 show the slightly thicker portion of the rigid member 3, indicated as 95, which extends from a point just below the lowest extremity of the lugs 98a and 98b for approximately one third of the length of the grip 5, to points indicated as 103a and 103k in FIGS. 24 and 25. Similar raised areas are provided within the clearance aperture 27 of the grip 5. The raised surfaces 95a and 95b of the rigid member 3 are adapted to be in sliding frictional engagementwith the raised surfaces within the clearance aperture 27 of the grip 5. As shown in FIG. 25, the clearance aperture 27 extends vertically the entire length of the grip 5 so that contact does not occur between the rearmost extremity of the clearance aperture 27 and the rearmost extremity of the rigid member 3 which is within the clearance aperture 27. The sliding frictional engagement between the surfaces indicated as 102a and 102k in FIGS. 24 and 27, prevents side to side movement of the grip 5 in the horizontal plane of bow while permitting rotation of the grip 5 in the vertical plane of the bow. L shaped bosses 97a and 9712 are disposed at the lowest extremity ofthe raised areas 95a and 95b and protrude outwardly therefrom. Circular bosses 96a'and 96b are disposed at the foremost extremity of the rigid member 3 at a point approximately halfway upthe raised surfaces a and 95b of the rigid member 3, the circular bosses 96a and 96b also protrude outwardly therefrom.

Lugs 98a and 98b extend from the lower extremity of the grip 5, being formed integrally therewith. When force is applied to the grip 5 at the point indicated by the arrow R in FIG. 25, the grip 5 rotates in the vertical plane until the forward flat areas 104a and 1041) of the lugs 98a and 98b contact the circular bosses 96 at the points designated as 101 on the periphery of the circular bosses 96. Thus, is a fulcrum point L established for the grip-lever. FIG. 25 also illustrates that the curving lowest extremities of the lugs 98a and 98b are adapted to permit contact of the lugs 98a and 98b on the vertically disposed flat surfaces 105a and l05b of the bosses 97a and 97b only at the points designated as a and 10Gb. Thus, is a reaction point K provided for the grip-lever. As in previously described embodiments, force applied at the point indicated by the arrow R in FIG. 25 is applied in magnified form to the reaction point K, via the fulcrum point L Downward vertical motion of the grip is restricted by means of contact of the circular lowest extremities of the lugs 98a and 98b at points designated as 99 on the horizontal flat surfaces 106a and 10611 of the L shaped bosses 97a and 97b. Upward vertical motion of the grip 5 is restricted by means of the block 80 and the resilient pad 33 operating with respect to the grip 5 and the rigid member 3 in a manner previously described and clearly illustrated in FIGS. 21 and 23.

The remaining embodiments of the invention are to be described with reference to FIGS. 28 through 40.

It will be noted that FIGS. 28 through 34 are confined to the functioning areas of the devices comprising the remaining embodiments of the invention. As previously stated, those areas of the bows not shown or described with reference to FIGS. 28 through 40 can be construed as being similar to those bows illustrated in, or previously described with reference to, FIGS. 1 through 27.

FIGS. 28 and 29 illustrate that the device of the invention is readily adaptable to the use of compound levers. The grip 5 is pivoted at its lower extremity by means of the horizontally disposed pin 43 which extends through the lugs 41a and 41b which are integral with the lower extremity of the grip 5, the pin 43 is in sliding frictional engagement with the inside diameter of the bushing 37 which is housing within a horizontally disposed circular aperture formed in the rigid portion 3. The pin 43 is horizontally retained by means of the pins 47 which are adapted to engage semi-circular ap-' ertures formed in the pin 43, the arrangement ofthe respective pins being similar to those previously described with reference to FIGS. 17, 18 and 19.

Horizontal side to side motion of the grip 5 with respect to the rigid member 3, is prevented by means of the flat surfaces 108a and 108b of the circular bosses 107a and 1071) and 119a and 119b, which are formed integrally with theinner surfaces of the lugs 41 and the outer surfaces of the rigid portion 3, being in sliding frictional engagement with respect to the vertical plane of the bow. The wear inserts 45, are attached to vertically disposed flat surfaces formed on the forward portions of the lugs 41a and 41b at points above the fulcrum pin 43, in a manner and for reasons previously described with reference to other embodiments of the invention under the same reference numerals.

Dual levers 110a and lb are vertically disposed on either side of the rigid member 3, and are adapted to pivot by means of the pin 112. The pin 112 is formed to comprise a body 128, two plain reduced portions 120a and 12% and two further reduced threaded portions 121a and l21b. The body 128 of the pin 112 is in sliding engagement with the inside diameter of the bushing 113, which is horizontally disposed within a circular aperture formed in the rigid member 3 and retained horizontally therein, by means of a pin device 117 similar to those previously described used to retain the fulcrum pin 43, and the cylindrical insert 72 shown in FIGS. 17 through 19.

The ends 183a and 183b of the bushing 113 are adapted to restrict side to side horizontal motion of the pin 112 within the bushing 13 when the levers 110a and 11012 are assembledto the pin 112 and clamped to the shoulders 125a and 12512, formed on the pin 112, by means of the locknuts 112a and 122b. Since the fixed bushing 113 is only slightly shorter than the body 128 of the pin 112, very little horizontal motion of the body 128 of the pin 112 is required before an end 183a or 183b of the bushing 113 bears against the inner surface of a lever 110a or 110b and further horizontal motion of the entire lever-pin assembly is prevented.

In FIGS. 28 and 29, it can be seen that bosses 118a and 11812 of approximately rectangular form are disposed at the lower extremities of the levers 110a and 11% on either side of the rigid member 3. The bosses 118a and ll8b are formed integrally with the rigid member 3, and protrude outwardly therefrom. The bosses 118a and ll8b are positioned at the rear extremity of the rigid member 3 and bear affixed to the flat vertical surfaces on their forward extremities, wear inserts 114a which may be affixed in a similar fashion to the wear strips 45a which are illustratednear the upper extremity of FIG. 29.

The levers 110a and 11% are fonned at their rear upper, and rear lower extremities, into curving areas which are designed to permit contact between said upper and lower extremities and the wear inserts 45 and 114 only at the points designated as 109 and 115 in FIG. 29. The vertically disposed, flat clearance areas 123 and 1231; and 124, are provided to further ensure that contact between the levers and the wear inserts 45a and 45b and 114a and 1141) occurs only as specified.

Vertically disposed, centrally located slots 116a and 11617 are formed completely through the levers 110a and 110b toward the lower extremities thereof, and are adapted to be in sliding frictional engagement with the plain reduced portions 120a and 120b of the pin 112. Locknuts 112a and 122b are located in threaded engagement with the threaded portions 121a and 12119 of the pin 112. Tightening the locknuts 122a and 12212 causes the inner surfaces of the levers 110a and 1l0b to be firmly clamped against the shoulders 125a and 12512 of the pin 112, which shoulders, are formed by the reduction of the diameters 120a and 12% relative to the diameter 128 of the body of the pin 112.

When the locknuts 122a and 122b are loosened, the levers 110a and 110b are freed for manual vertical adjustment within the restrictions of the vertically disposed slots 116a and 11612. And subsequent vertical adjustment of the contact points 109 and 115 on the wear inserts 45a and 45b and 114a andv 114b may be achieved.

It will be readily appreciated that, although the present embodiment provides for independent vertical adjustment of the levers 110a and 110b, the levers 110a and l10b may be quite easily linked together by means of a yoke, similar to the one identical at 58 in FIG. 15, thereby assuring identical vertical adjustment of both of the levers 110.

It will also be readily appreciated that measurement of the vertical adjustment of the levers 110a and 110b could be easily achieved in a fashion similar to that shown in FIG. 18, if a fixed pointer were attached to the forward extremity of the rigid member 3, and so positioned that the fixed tip of the pointer could be compared to horizontal lines or scale graduations marked on the upper surface of a lever 110a or 11%.

In the present embodiment, when force is applied to the grip 5, at the approximate point indicated by the arrow R, in FIG, 25, the grip 5 rotates in the vertical plane, about the fulcrum L provided by the pin 43, and the force is applied in magnified form to point 109 on

Claims (19)

1. In a long bow the combination comprising limbs joined together by a rigid central portion, a handgrip having a fulcrum means for pivotally mounting said handgrip about an axis that is perpendicular to the longitudinal axis of the bow and only pivotable in the plane of the bow and bowstring, a reaction point on said central portion for limiting the pivoting of said handgrip about the fulcrum means so that any force exerted by a user on the handgrip on one side of the fulcrum means, to flex both limbs when drawing the bow, will be transmitted through the handgrip to the rigid central portion at said reaction point on the other side of the fulcrum means and be resisted by a force offered by the reaction point whereby the moment produced by the force exerted by a user on the handgrip about the fulcrum means will be substantially equal to and opposite to the moment produced by the force produced at the reaction point about the fulcrum means, and an abutting means on said central portion to limit the pivotal movement of said handgrip after release of an arrow.

2. The bow recited in claim 1, further including means for adjustably varying the distance between said fulcrum means and said reaction point.

3. The bow recited in claim 2, wherein said fulcrum means is fixed and said reaction point is movable.

4. The bow as recited in claim 3, wherein a scale means is formed upon said rigid central portion and a pointer is formed upon said abutting means in a position to register with said scale so as to indicate the setting of said reaction point.

5. The bow recited in claim 2, wherein said reaction point is fixed and said fulcrum means is movable.

6. The bow as recited in claim 2, wherein said fulcrum means comprises a pair of screws threadedly mounted to said rigid central portion having conicAl tips which engage opposite sides of a plate secured to said hand grip and said reaction point comprises a protuberance on a pin threadedly mounted by its stem in said rigid central portion by means of a knurled finger wheel in threaded engagement with said stem which is mounted for rotating movement within said rigid central portion whereby the displacement of said pin may be varied.

7. A bow as recited in claim 2, in which said fulcrum means comprises a bushing close fitted in an aperture in said hand grip and a pin received in a sliding fit within said bushing and projecting from the ends of said bushing, the ends of said pin being tightly received in said rigid central portion, and said reaction point comprises lugs integral with said hand grip and depending therefrom which contact pins mounted upon a yoke and disposed so as to be in contact with said rigid central portion when squeezed between said lugs and said rigid central portion, said yoke being adjustably connected to said hand grip portion.

8. The bow as recited in claim 2, wherein said fulcrum means comprises screws threadedly mounted to said hand grip portion and axially aligned with recesses in opposed sides of said rigid central portion, the conical tips of said screws being aligned with said recesses, and said reaction point comprising pin means secured to a pair of plates slidably mounted within a recess of said rigid central portion which pin means is adapted to abut lugs depending from said hand grip, said plates being clamped against the opposed sides of said rigid central portion by screws extending through each of said plates threadedly engaging said plates.

9. The bow as recited in claim 2, wherein said reaction point comprises a lever pivotally mounted to said rigid central portion and engaging said rigid central portion at one end thereof, the other end thereof engaging said hand grip to form a compound lever between said hand grip and said rigid central portion.

10. The bow as claimed in claim 2, wherein said fulcrum means comprises a circular portion of said hand grip slidably engaged within a mating aperture within said rigid central portion and said reaction point comprises a pin mounted to said rigid portion for engaging a spherical end of a stem which is threadedly mounted for adjustable motion with respect thereto.

11. The bow as recited in claim 2, wherein said fulcrum means comprises a sphere mounted to said hand grip by means of a stem threadedly engaged within said hand grip so that said fulcrum is adjustable with respect to said hand grip, said sphere contacting a flat surface formed upon said rigid central portion and said reaction point comprises a point formed upon said rigid central portion which contacts a flat surface formed upon said hand grip.

12. The bow as recited in claim 2, wherein said fulcrum means comprises members having conical tips mounted to said hand grip which engage axially aligned depressions in a member which is secured to said rigid central portion and said reaction point comprises a nut threadedly mounted on a screw which is, in turn, secured to said rigid central portion and, said nut being adapted to engage in point contact a pin secured to said hand grip.

13. The bow as recited in claim 1, further including means for determining the orientation of the rigid central portion of said bow with respect to a vertical plane whereby the balance of moments about the fulcrum means may be determined.

14. The bow as recited in claim 13, wherein said determining means includes a member pivotally mounted to said rigid central portion and weighted at its free end to operate as a plumb.

15. The bow as recited in claim 14, further including a scale marked in degrees formed upon said rigid central portion adjacent said member, the free end of said member being formed at a point to indicate upon said scale the degree of tilt of said bow with respect to the vertical plane.

16. The bow as recited in claim 1, further including at least one reSilient pad means disposed between said hand grip and said rigid member to absorb shocks accompanying release of an arrow.

17. The bow as recited in claim 1, wherein said fulcrum means comprises a curved portion on said rigid central portion which contacts a flat portion of said hand grip and said reaction point comprises a lug having a flat face extending upwardly from said rigid central portion which abuts a circular portion of said hand grip, said hand grip surrounding three sides of said rigid central portion in a U-shaped manner and having at least one member closing the U about said rigid portion and including a resilient pad for abutting said rigid member.

18. The bow as recited in claim 1, wherein said fulcrum means comprises circular members extending from opposite sides of said rigid central portion which engage flat portions of said hand grip and said reaction point comprises lugs on said rigid central portion having flat faces which abut curved portions of said hand grip at point contact.

19. The bow as recited in claim 1, wherein said fulcrum means comprises a pin longitudinally engaged between a first V-shaped slot formed in said hand grip and a second V-shaped slot formed in said rigid central portion and said reaction point comprises a sphere engaging an aperture formed in a lug extending upwardly from said rigid central portion and an aperture formed in said hand grip.

Images