Archery bows have been in existence in many forms for thousands of years. Many ancient civilizations had variety of shaped bows that gave the bow unique features and more power. In recent years, crossbows, compound bows, and recurve bows have also had many improvements to increase power, improve accuracy, decrease overall size and weight, and decrease the shock that the weapon produces during and after the shot. The shape of the limbs can have a significant impact on the displaced energy.
In general terms, this disclosure is directed to a dual inverted limb for a bow. In one possible configuration and by non-limiting example, the dual inverted limb includes a pair of limbs where each limb extends from a central riser in the forward direction away from the shooter and has a limb tip that ends on the opposite side of the riser near the shooter.
According to certain aspects of the present disclosure, a bow is adapted to shoot a projectile along a direction of flight. The bow includes a riser, a first limb, a second limb, and a drawstring. The riser extends between a first end and a second end in a direction generally perpendicular to the direction of flight. The riser includes a first side and a second side that each extend between the first and the second ends of the riser. The first side of the riser is spaced from the second side of the riser along the direction of flight. The riser includes a first mount that is adjacent the first end of the riser and a second mount that is adjacent the second end of the riser. The first limb extends along a first contour from a proximal end to a distal end. The first limb is mounted to the first mount of the riser adjacent the proximal end of the first limb. The first contour includes a first attachment segment that extends from a proximal end to a distal end. The first attachment segment is positioned adjacent the first mount. The second limb extends along a second contour from a proximal end to a distal end. The second limb is mounted to the second mount of the riser adjacent the proximal end of the second limb. The second contour includes a second attachment segment that extends from a proximal end to a distal end. The second attachment segment is positioned adjacent the second mount. The drawstring is operably connected to the first and the second limbs adjacent the distal ends of the first and the second limbs. The first and the second attachment segments at least partially extend in the direction of flight from the proximal end to the distal end of the corresponding attachment segment.
Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims.
Today, most crossbow manufacturers are making crossbows with almost parallel limbs to reduce recoil, but are also faced with reducing powerstroke in accomplishing the task. Furthermore, they are increasing the size and width of the riser to position the limbs to get them in position to be mounted near parallel. Essentially, getting the limbs to this position reduces powerstroke and increases the weight of the crossbow which are both negative aspects. Finally, crossbow manufacturers have been designing the foot stirrup into the riser to take advantage of the extra space provided by the larger riser.
Most compound bow manufacturers are designing bows to reduce felt hand shock and recoil. The most common method is to get the limbs either flexed or positioned to be in a near parallel position. In doing so, the riser for the bow becomes much longer and deeper and adds weight to the overall bow. Furthermore, manufacturers are attempting to minimize limbs movement to keep the limbs on center, shot after shot. The limb designs do not pivot left/right about their neutral axis, thus causing the string to move with the slightest movement in the limb pocket tensioning system.
Modern recurve bows do not attempt to cancel recoil from the shot. Modern recurves need the limbs pointing in the near vertical direction to get enough draw length from the flexing of the limbs tips, and therefore they are very long (e.g., 38″ or more) with long slightly curved limbs to get sufficient limb tip flex to obtain the draw length.
According to the principles of the present disclosure, limb, riser, and limb tensioning systems, referred to herein as Dual Inverted Limb Systems, include configurations that provide various advantages over prior art bows using prior art limb and riser systems. The Dual Inverted Limb Systems disclosed herein can be used to make compound bows, crossbows, recurve bows, compound crossbows, and/or recurve crossbows to reduce felt hand shot recoil, improve compactness, improved energy density, and/or improve accuracy. Furthermore, the Dual Inverted Limb Systems preserve powerstroke in compound crossbows by starting the limbs in a forward direction, thereby moving cams of the compound crossbow forward. Also, the Dual Inverted Limb Systems reduce the riser size and/or weight for all types of crossbows and bows by allowing lightweight composite limbs (e.g., carbon fiber based composites, glass fiber based composites, etc.) to make up more of the bow. The Dual Inverted Limb Systems may include one or more of the following features: 1) parallel limbs or parallel limb portions; 2) reduced riser size; 3) limb contour paths continuing forward from riser mount, reversing direction, and ending reward at limb tip; 4) limb tension system that may include a pivot, a tension bolt, and a clamp and may be adjustable; 5) limbs that rotate about a neutral axis to maintain string alignment; and, 6) limbs with sweeping shape that extends a contour length of the limb for increases flex. Any one of the aforementioned items provide new improvements over prior art technologies, and, alone or combined, produce improvements to prior art bows. By combining certain of these items, a crossbow, compound bow, recurve bow, compound crossbow, and/or recurve crossbows can be produced that is shorter, lighter, more accurate, and/or lower cost. Certain embodiments provide a method of producing a recurve bow with limb portions that are near perpendicular with the riser to reduce recoil hand shock.
A bow 600 of
As illustrated at
The Dual Inverted Limb Systems technology allows the riser (e.g., the riser 610) to be minimized to the grip and sight window and the limbs (e.g., the limbs 650A, 650B) shaped to position the limb tips to meet the braceheight, axle-to-axle spacing, and overall size of the bow for crossbows, compound bows, recurve bows, compound crossbows, and/or recurve crossbows thereby reducing cost and weight.
In considering details of the swept shape/contour of the limbs 650A, 650B, instead of the limbs starting in a rearward direction, towards the shooter, and staying in that direction, the Dual Inverted Limb Systems technology uses limbs that are either laminated to shape, cast to shape, or molded to shape. The limbs 650A, 650B are then preloaded about 2″ to 4″ from the relaxed state to preload a draw string 194. The limb design allows for increased limb length in a very compact space by the sweeping shape/contour. More specifically, the limbs 650A, 650B are strategically started in the forward direction and then swept back in at about a 1″ to 10″ radius to position the limb tip in the ideal location. The limbs 650A, 650B can also have additional sweeps in other directions to increase preloading of the limbs 650A, 650B, but preferably end rearward of the starting point.
The Dual Inverted Limb Systems technology uses a new type of limb tension system. Unlike prior art cantilevered limbs which are tensioned with a mid point pivot and an end tensioning block (where the limb is essentially bent over a fixed mandrel and the limb is flexed by tensioning or pulling down on the limb end), the Dual Inverted Limb Systems technology does this oppositely, in that the limb end is fixed and the mid-point pivot is the tensioning means. Also, the limb tensioning means are on the opposite side of the limb or the interior of the limb side. Allowing the limb tension to work in this manner permits the limb to move about the neutral axis when combined with the limb shape.
The Dual Inverted Limb Systems technology has a cantilevered limb that has an overall arc shape that folds in a near semi-circle. Inherent to this design, when the limbs move or pivot left to right, the cam position moves about the center of rotation and keeps the cam in almost the same position. This is in contrast to a cantilevered limb that will pivot about a small arc where the limb tip or cams have significant or amplified movement with a small amount of limb movement.
The Dual Inverted Limb Systems technology allows for an extended limb length in a very compact area. The increased limb length allows the limbs (e.g., the limbs 650A, 650B) to have an extreme radius and flex over the entire length of the limb. Furthermore, the increased length can be used to allow the Dual Inverted Limb Systems technology to be used on recurve bows that naturally require increased limb movement at the limb tip without the corresponding increased size in the bow. The sweeping motion adds limb length and allows the limb to be placed near or past parallel to improve accuracy, reduce recoil, and add energy capacity to the limb.
According to the principles of the present disclosure, a riser and bow limb configuration can be adapted for use in at least four configurations of bows 100. In particular, a recurve crossbow 300, as illustrated at
Turning now to
Turning now to
Turning now to
Turning now to
Turning now to
Hereinafter, the generic bow 100 will be referred to and will further apply to bows 200, 300, 400, 500, 600, and 800, where applicable. The bow 100 is adapted to shoot the projectile 96 along a direction of flight DF. A shooter may use the bow 100 to shoot the projectile 96 at various targets. Typically, the projectile 96 is an arrow. The shooter may use the bow 100 to shoot the arrow 96 at targets such as practice targets and/or at wild game. By shooting the projectile 96 from the bow 100, the shooter may hit the target with the projectile 96 traveling at sufficient speed and with sufficient energy to bring down the target.
The shooter typically stores energy in the bow 100 by drawing a drawstring arrangement 190 from an undrawn configuration 92 (see
The drawstring arrangement 190 includes a first connection arrangement 192A that is connected to a first string mounting arrangement 178A of the first limb 150A and a second connection arrangement 192B that is connected to a second string mounting arrangement 178B of the second limb 150B. The connection arrangements 192A, 192B and the string mounting arrangements 178A, 178B may include any known components, techniques, configurations that join a drawstring to a limb.
In the recurve crossbow 300 and the recurve bow 400, the drawstring arrangement 190 includes the drawstring 194, and the drawstring 194 includes the first and the second connection arrangements 192A, 192B (e.g., a knot) at opposite ends 194A, 194B of the drawstring 194. The first limb 150A includes a first string engaging portion 904A (see
In the compound crossbow 500 and the compound bows 600 and 800, the drawstring arrangement 190 includes the drawstring 194, a first cam 908A, and a second cam 908B (see
In the bows 200, 300, and 500, the drawstring arrangement 190 may be released by the shooter pulling a trigger 920 (see
The shooter may hold the bows 400, 600, and 800 by the handle 914 (i.e., the grip). The shooter may draw the drawstring 194 of the drawstring arrangement 190 with his/her fingers and thereby deliver energy to the first and the second limbs 150A, 150B. By releasing the drawstring 194, the drawstring 194 propels the projectile 96 along the direction of flight DF.
According to the principles of the present disclosure, the riser 110 and the limbs 150A, 150B include unique and beneficial relationships with each other. The first limb 150A is connected to the second limb 150B by the riser 110.
The riser 110 includes the first mounting arrangement 120A and the opposite second mounting arrangement 120B. The riser 110 extends between a first end 112 and a second end 114. The riser 110 generally extends between the first end 112 and the second end 114 in a direction DR. The direction DR is generally perpendicular to the direction of flight DF. The bows 200, 300, and 500 typically orient the riser 110 with the direction DR extending generally horizontally. The bows 400, 600, and 800, typically have the riser 110 oriented with the direction DR extending in a vertical direction. The riser 110 includes a first side 116 and a second side 118. The first and the second sides 116, 118 generally extend between the first and the second ends 112, 114 of the riser 110. The first side 116 is generally spaced from the second side 118 along the direction of flight DF. The first side 116 of the riser 110 may generally define a first plane P1. The second side 118 of the riser 110 may generally define a second plane P2.
The first mounting arrangement 120A may include a first mount 122A adjacent the first end 112 of the riser 110. In certain embodiments, the first mount 122A adjoins the first end 112 of the riser 110. As illustrated at
An included angle α may be defined between the first mount 122A and the second mount 122B and/or may be defined between the first mounting plane P3 and the second mounting plane P4. In certain embodiments, the included angle α may range from about 0° to about 160°. In other embodiments, the included angle α may range from about 15° to about 145°. In still other embodiments, the included angle α may range from about 30° to about 130°. In still other embodiments, the included angle α may range from about 45° to about 75°. In yet other embodiments, the included angle α may range from about 55° to about 65°. The nominal value of the included angle α may be 60°, as illustrated. As illustrated, the included angle α opens in the direction of flight DF. In certain embodiments, the included angle α may form a vertex positioned on the bow 100 (see
The first limb 150A may include a first attachment arrangement 156A. The first attachment arrangement 156A may be mounted to the first mounting arrangement 120A of the riser 110. In particular, the first limb 150A may be attached to the first mount 122A adjacent the proximal end 152A. In certain embodiments, the proximal end 152A may be adjacent the first mount 122A. In other embodiments, the proximal end 152A may adjoin the first mount 122A. By holding the first limb 150A, the first mounting arrangement 120A may angle the held portion of the first limb 150A about the first mounting plane P3. The second limb 150B may include a second attachment arrangement 156B. The second attachment arrangement 156B may be mounted to the second mounting arrangement 120B of the riser 110. In particular, the second limb 150B may be attached to the second mount 122B adjacent the proximal end 152B. In certain embodiments, the proximal end 152B may be adjacent the second mount 122B. In other embodiments, the proximal end 152B may adjoin the second mount 122B. By holding the second limb 150B, the second mounting arrangement 120B may angle the held portion of the second limb 150B about the second mounting plane P4.
The first limb 150A extends from the proximal end 152A to the distal end 154A. The first limb 150A may extend along the first contour 180A. The first contour 180A may include a first attachment segment 182A. The first attachment segment 182A may extend along the first limb 150A running adjacent to the first attachment arrangement 120A. The second limb 150B extends from the proximal end 152B to the distal end 154B. The second limb 150B may extend along the second contour 180B. The second contour 180B may include a second attachment segment 182B. The second attachment segment 182B may extend along the second limb 150B running adjacent to the second attachment arrangement 120B.
The first limb 150A may include the first string mounting arrangement 178A. The first string mounting arrangement 178A may be positioned adjacent the distal end 154A. In certain embodiments, the first string mounting arrangement 178A adjoins the distal end 154A of the first limb 150A. The first attachment segment 182A may extend from a proximal end 182AP to a distal end 182AD. The first attachment segment 182A may be substantially linear and the first limb 150A may define substantially planar mounting surfaces adjacent the first attachment segment 182A. The second limb 150B may include a second string mounting arrangement 178B. The second string mounting arrangement 178B may be positioned adjacent the distal end 154B. In certain embodiments, the second string mounting arrangement 178B adjoins the distal end 154B of the second limb 150B. The second attachment segment 182B may extend from a proximal end 182BP to a distal end 182BD. The second attachment segment 182B may be substantially linear and the second limb 150B may define substantially planar mounting surfaces adjacent the second attachment segment 182B.
As the limbs 150A, 150B extend along the contours 180A, 180B, the contours 180A, 180B may define various curvatures, tangencies, inflexion points, reversals of curvature, and otherwise define a winding path. A length LC may define a length of the contours 180A and/or 180B as they extend along their path (see
In certain embodiments, the limb 150A includes a single monolithic structural member. In certain embodiments, the limb 150B includes a single monolithic structural member. In other embodiments, the limbs 150A and/or 150B may include a pair of the limb members 150A1 150A2 and/or 150B1 150B2, respectively. The pair of the limb members 150A1 150A2 and/or 150B1 150B2 may straddle at least a portion of the mounting arrangements 120A and 120B, respectively. In embodiments with the single monolithic structural member, the limbs 150A, 150B may include a fork at the proximal ends 152A, 152B, respectively, and thereby straddle at least a portion of the mounting arrangement 120A, 120B. The single monolithic structural member and/or the pair of limb members 150A1 150A2 and/or 150B1 150B2 may taper as the limbs 150A, 150B extends along the contour 180A, 180B. The limbs 150A, 150B may taper both in thickness and/or in width, and thereby match structural loads (e.g., bending moments) placed on the limbs 150A, 150B as the limbs 150A, 150B are moved between the undrawn configuration 92 and the drawn configuration 94 and/or otherwise actuated.
The limbs 150A, 150B may be made of a composite material (e.g., a carbon fiber based composite material, a glass fiber based composite material, etc.). The limbs 150A, 150B may be molded. The limbs 150A, 150B may be laid up over a mandrel and thereby receive their shape from the mandrel. The proximal ends 152A, 152B of the limbs 150A, 150B may include a round, a hole, a pin, and/or other member that allows for rotational mounting. The mounting arrangements 120A, 120B may include a cradle, a pin, and/or a round that receives the proximal ends 152A, 152B of the corresponding limb 150A, 150B. The limbs 150A, 150B may thereby connect at the proximal ends 152A, 152B, respectively, with the mounting arrangements 120A, 120B and thereby form a rotationally free mount 950. The rotationally free mount 950 may include friction. The rotationally free mount 950 may allow the corresponding limb 150A, 150B to rotate relative to the corresponding mounting arrangement 120A, 120B and thereby substantially relieve bending moments that may otherwise be transferred from the limb 150A, 150B to the mounting arrangement 120A, 120B at the proximal end 152A, 152B or adjacent to the proximal end 152A, 152B.
The mounting arrangements 120A, 120B may further include a clamp 952 that holds (i.e., constrains) the corresponding limb 150A, 150B from rotating about the corresponding mounting arrangement 120A, 120B. In certain embodiments, the clamp 952 is adjustable and thereby allows the limb 150A, 150B to be angularly adjusted with respect to the riser 110 about the rotationally free mount 950. As illustrated at
As illustrated in the figures, various components and features of the bow 100 may have various relative positions to other components and features of the bow 100. In particular, the proximal ends 152A, 152B of the limbs 150A, 150B may each be spaced in the direction DS from the plane P2 that generally bounds the second side 118 of the riser 110. Alternatively, the proximal ends 152A, 152B may each be positioned along the plane P2, or the proximal ends 152A, 152B may each be positioned between the first plane P1 that generally bounds the first side 116 of the riser 110 and the second plane P2 of the riser 110. The distal ends 154A, 154B of the limbs 150A, 150B may each be spaced from the plane P2 in the direction DS. Alternatively, the distal ends 154A, 154B may each be positioned along the plane P2 when the bow 100 is in the undrawn configuration 92. Alternatively, the distal ends 154A, 154B may each be positioned between the first plane P1 and the second plane P2 when the bow 100 is in the undrawn configuration 92. Alternatively, the distal ends 154A, 154B may each be spaced from the plane P1 in the direction of flight DF when the bow 100 is in the undrawn configuration 92. Alternatively, the distal ends 154A, 154B may each be spaced from the plane P2 in the direction DS when the bow is in the drawn configuration 94.
As illustrated in the figures, the interface geometry between the limbs 150A, 150B and the riser 110 may vary in various embodiments. In particular, at least opposite portions of the first and the second attachment segments 182A, 182B may be angled relative to each other such that the opposite portions of the attachment segments 182A, 182B extend outwardly away from each other as the attachment segments 182A, 182B at least partially extend in the direction of flight DF. In certain embodiments, at least a portion of each of the first and the second attachment segments 182A, 182B are substantially linear. In certain embodiments, the first and the second attachment segments 182A, 182B are substantially parallel to each other, at least about the substantially linear portions. In other embodiments, the first and the second attachment segments 182A, 182B are angled relative to each other, at least about the substantially linear portions. In certain embodiments, the first and the second attachment segments 182A, 182B are angled relative to each other, at least about the substantially linear portions, such that the first and the second attachment segments 182A, 182B extend outwardly away from each other as the attachment segments 182A, 182B partially extend in the direction of flight DF. In other embodiments, the first and the second attachment segments 182A, 182B may continuously curve, and the included angle α may be defined between positions on opposite curves.
As illustrated at
As illustrated in the figures, the first contour 180A and the second contour 180B may have unique and beneficial shapes. In particular, as illustrated at
In certain embodiments, the protruding segments 180AP 180BP of the first and the second contours 180A, 180B each follow the corresponding attachment segment 182A, 182B. The protruding segments 180AP, 180BP may each extend beyond the plane P1. The proximal end of each of the protruding segments 180AP, 180BP may adjoin the distal end of the corresponding attachment segment 182A, 182B. Each of the protruding segments 180AP, 180BP may linearly extend adjacent the proximal end of the corresponding protruding segments 180AP, 180BP in the direction DM.
As illustrated at
As illustrated at
As illustrated at
As illustrated at
According to the principles of the present disclosure, the bow 100 includes a unique and beneficial mounting arrangement between the riser 110 and the limbs 150A, 150B. In particular, as illustrated at
The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/489,736, filed on May 25, 2011, titled DUAL INVERTED LIMB, which is hereby incorporated by reference in its entirety.
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Classic-bow.com, Traditional, recurve bows, Bow Shop, Handmade Traditional Hungarian Mongolian Schytian recurve. |
Number | Date | Country | |
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20130042848 A1 | Feb 2013 | US |
Number | Date | Country | |
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61489736 | May 2011 | US |