Patent Publication Number: US-2022228833-A1

Title: Narrow crossbow with large power stroke

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/348,018, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Jun. 15, 2021, which is a continuation of U.S. patent application Ser. No. 16/779,809, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Feb. 3, 2020, which is a continuation of U.S. patent application Ser. No. 16/213,299, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Dec. 7, 2018, which is a continuation of U.S. patent application Ser. No. 15/838,561, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Dec. 12, 2017, which is a continuation of U.S. patent application Ser. No. 15/409,257, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Jan. 18, 2017, which is a continuation of U.S. patent application Ser. No. 15/261,812, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Sep. 9, 2016, which is a division of U.S. patent application Ser. No. 15/005,966, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Jan. 25, 2016, which is a continuation of U.S. patent application Ser. No. 14/937,403, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Nov. 10, 2015, which is a continuation of U.S. Ser. No. 14/302,764, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Jun. 12, 2014, which is a continuation of U.S. patent application Ser. No. 14/192,494, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Feb. 27, 2014, which is a continuation of U.S. patent application Ser. No. 13/848,880, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Mar. 22, 2013, which is a continuation of U.S. Ser. No. 13/312,161, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Dec. 6, 2011, which is a division of U.S. patent application Ser. No. 12/868,012, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Aug. 25, 2010, which is a continuation-in-part of U.S. patent application Ser. No. 11/948,319, entitled NARROW CROSSBOW WITH LARGE POWER STROKE, filed Nov. 30, 2007, which claims priority from U.S. Ser. No. 60/868,157, entitled CROSSBOW, filed Dec. 1, 2006, all of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Crossbows have been used for many years as a weapon for hunting and fishing, and for target shooting. In general, a crossbow includes a main beam including a stock member and a barrel connected to the stock member. The barrel typically has an arrow receiving area for receiving the arrow that is to be shot. The crossbow also includes a bow assembly supported on the main beam that includes a bow and a bowstring connected to the bow for use in shooting arrows. A trigger mechanism, also supported on the main beam, holds the bowstring in a drawn or cocked condition and can thereafter be operated to release the bowstring out of the uncocked condition to shoot the arrow. One characteristic of a crossbow is termed a power stroke. The power stroke is the distance along the main beam that the bowstring moves between the uncocked condition and the cocked condition. 
     One of the trends in the industry today is to advertise very large power strokes, such as 16 inches, 17 inches or 18 inches. Such very large power strokes provide the potential for more speed and energy. But there are corresponding problems. One such problem is the added difficulty in manually cocking the crossbow. More specifically, the operator must have relatively long arms in order to properly reach the bowstring for cocking purposes. Another problem with relatively large power strokes is the increased angle of the bowstring when placing it into the cocked position. This also makes it more difficult to cock the crossbow. 
     Another problem with known crossbows is related to their width. More specifically, to obtain an adequate power stroke it is known to provide crossbows that are relatively wide. Such wide crossbows may be difficult for a hunter to operate while following prey, side to side, because the crossbow is less maneuverable and the hunter is more likely to bump into surrounding objects. 
     What is needed is a relatively narrow crossbow having a relatively large power stroke. In this way the disadvantages known in the art can be overcome in a way that is better, more efficient and that provides better overall results. 
     SUMMARY 
     According to some embodiments of this invention, a crossbow may include: a main beam; a riser: 1) supported to the main beam; 2) having a first end with a first limb attachment surface; 3) having a second end opposite the first end with a second limb attachment surface; and 4) having a U-shaped opening; a first bow limb that has: 1) a first end supported to the first limb attachment surface of the riser; 2) a second end opposite the first end; and 3) a length L 1 ; a second bow limb that has: 1) a first end supported to the second limb attachment surface of the riser; and 2) a second end opposite the first end; and 3) a length L 2 ; and a bowstring: 1) adapted to propel an arrow; 2) received on the second end of the first bow limb; and 3) received on the second end of the second bow limb. The first and second limb attachment surfaces may be separated such that a minimum distance between them is: (a) at least as wide as a user&#39;s foot; but (b) not greater than about 5 inches. The U-shaped opening: (a) may extend between the first and second limb attachment surfaces; and (b) may be designed to receive a user&#39;s foot. Length L 1  and length L 2  may both be less than 15 inches. 
     According to some embodiments of this invention, a crossbow may include: a main beam; a riser: 1) supported to the main beam; 2) having a first end with a first limb attachment surface; 3) having a second end opposite the first end with a second limb attachment surface; and 4) having a U-shaped opening; a first bow limb that has: 1) a first end supported to the first limb attachment surface of the riser; 2) a second end opposite the first end; 3) a hinge point; and 4) a thickness that varies along the length of the first bow limb from the first end to the hinge point; a second bow limb that has: 1) a first end supported to the second limb attachment surface of the riser; 2) a second end opposite the first end; 3) a hinge point; and 4) a thickness that varies along the length of the second bow limb from the first end to the hinge point; and a bowstring: 1) adapted to propel an arrow; 2) received on the second end of the first bow limb; and 3) received on the second end of the second bow limb. The first and second limb attachment surfaces may be separated such that a minimum distance between them is: (a) at least as wide as a user&#39;s foot; but (b) not greater than about 5 inches. The U-shaped opening: (a) may extend between the first and second limb attachment surfaces; and (b) may be designed to receive a user&#39;s foot. 
     According to some embodiments of this invention, a crossbow may include: a main beam having an axis of elongation; a riser: 1) supported to the main beam; 2) having a first end with a first limb attachment surface; 3) having a second end opposite the first end with a second limb attachment surface; and 4) having a U-shaped opening; a first bow limb that has: 1) a first end supported to the first limb attachment surface of the riser; and 2) a second end opposite the first end; a second bow limb that has: 1) a first end supported to the second limb attachment surface of the riser; and 2) a second end opposite the first end; a first wheel: 1) mounted to the second end of the first bow limb; and 2) pivotal with respect to the first bow limb about a first pivot axis; a second wheel: 1) mounted to the second end of the second bow limb; and 2) pivotal with respect to the second bow limb about a second pivot axis; and a bowstring: 1) adapted to propel an arrow; 2) movable between a cocked position and an un-cocked position; and 3) operatively engaged to the first and second wheels. The first and second limb attachment surfaces may be separated such that a minimum distance between them is: (a) at least as wide as a user&#39;s foot; but (b) not greater than about 5 inches. The U-shaped opening: (a) may extend between the first and second limb attachment surfaces; and (b) may be designed to receive a user&#39;s foot. When the bowstring moves between the cocked position and the un-cocked position it may move along the axis of elongation a power stroke distance (PD). The first pivot axis and the second pivot axis may be separated by a wheel distance (WD) when the bowstring is in the un-cocked position. The ratio of WD to PD (WD/PD) may be less than 2.0. 
     One advantage of this invention according to some embodiments is that a relatively narrow crossbow having a relatively large power stroke is provided. 
     Another advantage of this invention according to some embodiments is that a crossbow may be easy to manually cock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may take physical form in certain parts and arrangement of parts embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein: 
         FIG. 1  is a top perspective view of a crossbow according to certain embodiments of the invention. 
         FIG. 2  is a side view of a crossbow similar to that shown in  FIG. 1 . 
         FIG. 3  is a top view of the crossbow of  FIG. 2 , showing the crossbow in the cocked condition. 
         FIG. 4  is a perspective end view of the crossbow shown in  FIG. 3 . 
         FIG. 5  is a perspective end view of a portion of the crossbow showing the compound bow. 
         FIG. 6  shows limb dimensions according to one embodiment of this invention. 
         FIG. 7  is a close-up top perspective view of a riser according to one embodiment of this invention. 
         FIG. 8  is a perspective view of a crossbow showing how a foot stirrup may engage a ground surface. 
         FIG. 9  is a close-up top perspective view showing how the bow limbs may be received within riser pockets according to one embodiment of this invention. 
         FIG. 10  is a close-up top perspective view showing how the riser may be connected to the main beam according to one embodiment of this invention. 
         FIG. 11  is a close-up end view of the riser shown in  FIG. 10 . 
         FIG. 12  shows various riser views and dimensions according to one embodiment of this invention. 
         FIG. 13  is a perspective side view of two wheels according to one embodiment of this invention. 
         FIG. 14  is a top view of the wheels shown in  FIG. 13 . 
         FIG. 15  is a perspective top view wheels shown in  FIG. 13 . 
         FIG. 16  shows various wheel views and dimensions according to one embodiment of this invention. 
         FIG. 17  illustrates how bushings may be positioned within one of the pulley wheels according to one embodiment of this invention. 
         FIG. 18  is a close-up perspective view showing how a wheel may be attached to the crossbow limbs and to the bowstring. 
         FIG. 19  is a top view of the wheels shown in  FIG. 18 . 
         FIG. 20  is a top view of another wheel attached to crossbow limbs and to the bowstring. 
         FIG. 21  is a graph of an example draw weight to power stroke line. 
     
    
    
     DEFINITIONS 
     The following definitions are controlling for the disclosed invention: 
     “Arrow” means a projectile that is shot with (or launched by) a bow assembly. 
     “Bow” means a bent, curved, or arched object. 
     “Bow Assembly” means a weapon comprising a bow and a bowstring that shoots or propels arrows powered by the elasticity of the bow and the drawn bowstring. 
     “Bowstring” means a string or cable attached to a bow. 
     “Compound Bow” means a crossbow that has wheels, pulleys or cams at each end of the bow through which the bowstring passes. 
     “Crossbow” means a weapon comprising a bow assembly and a trigger mechanism both mounted to a main beam. 
     “Draw Weight” means the amount of force required to draw or pull the bowstring on a crossbow into a cocked condition. 
     “Main Beam” means the longitudinal structural member of a weapon used to support the trigger mechanism and often other components as well. For crossbows, the main beam also supports the bow assembly. The main beam often comprises a stock member, held by the person using the weapon, and a barrel, used to guide the projectile being shot or fired by the weapon. 
     “Power Stroke” means the linear distance that the bowstring is moved between the uncocked condition and the cocked condition. 
     “Trigger Mechanism” means the portion of a weapon that shoots, fires or releases the projectile of a weapon. As applied to crossbows, trigger mechanism means any device that holds the bowstring of a crossbow in the drawn or cocked condition and which can thereafter be operated to release the bowstring out of the drawn condition to shoot an arrow. 
     “Weapon” means any device that can be used in fighting or hunting that shoots or fires a projectile including bow assemblies and crossbows. 
     DETAILED DESCRIPTION 
     Referring now to the FIGURES wherein the showings are for purposes of illustrating multiple embodiments of the invention only and not for purposes of limiting the same,  FIGS. 1-4  show a crossbow  10  according to one embodiment of this invention. While the crossbow shown uses a compound bow, it should be understood that this invention will work well with any type of crossbow chosen with sound judgment by a person of ordinary skill in the art. The crossbow  10  has a main beam  12  including a stock member  14  and a barrel member  16 . The main beam  12  may be made by assembling the stock member  14  and the barrel member  16  together as separate components or, in another embodiment, the main beam  12  may be made as one piece. A handgrip  18  may be mounted to the main beam  12  in any conventional manner chosen with sound judgment by a person of ordinary skill in the art. A trigger mechanism  20  suitable for shooting an arrow is mounted to the main beam  12  in any suitable manner. It should be noted that the crossbow  10  may comprise any trigger mechanism chosen with sound judgment by a person of ordinary skill in the art. The crossbow  10  also includes a bow assembly  30  adapted to propel an arrow and having a bow  32  and a bowstring  34 . The bow  32  includes a pair of limbs  36 ,  36  that receive the bowstring  34  in any conventional manner chosen with sound judgment by a person of ordinary skill in the art. For the embodiment shown, a pair of wheels or pulleys  38 ,  38  mounted to the limbs  36 ,  36  receive the bowstring  34  in a known manner. The bow may also include a riser or block  40  having a pair of limb pockets  42 ,  42  that receive the limbs  36 ,  36 , as shown. Many other crossbow components may be optionally used with a crossbow using this invention. The crossbow  10  shown, for example, includes a scope  50  attached to a scope mount  52  that is supported on the main beam  12 , and one or more swivel studs  54  (see  FIG. 2 ). Other optional components shown include a cocking unit  56  and an arrow retention spring  58 . As the operation of these components is well known to those of skill in the art, no further details will be provided. 
       FIG. 1  shows the crossbow  10  in an uncocked condition while  FIGS. 2-4  show the crossbow  10  in a cocked condition. The power stroke is thus shown, in  FIG. 1 , with reference PD. For this invention the power stroke PD is at least 10 inches. In a more specific embodiment the power stroke PD is at least 12 inches. In yet a more specific embodiment the power stroke PD is about 13 inches. With reference to  FIGS. 2 and 4 , each wheel  38 ,  38  pivots about a pivot axis A-A. When the crossbow  10  is in the uncocked condition, the distance between the two pivot axes is shown with reference WD, see  FIG. 1 . To illustrate the relative narrow design of the crossbow according to this invention, in one embodiment the ratio WD/PD is less than 2.0. In a more specific embodiment the ratio WD/PD is less than 1.8. In getting more specific embodiments the ratio WD/PD is less than 1.6. 
     With reference now to  FIGS. 1-6 , a limb design according to one embodiment of this invention will now be described. Each limb  36  has a first end  60  that is received within the corresponding pocket  42  and a second end  62  that is operatively connected to the bowstring  34 . Each limb  36  also has, as seen the best in  FIG. 6 , a length L 1 , a height H 1  (measured from bottom to top when the crossbow is held in the normal operating position), and a thickness T 1 . Each limb  36  also has a hinge point HP which is the point along the length L 1  at which the thickness T 1  is at a minimum. It should be noted that the thickness T 1  of the limb  36  according to one embodiment varies continuously along its length L 1  from the first end  60  to the hinge point HP. This is believed to be a first in the industry as known limbs maintain a constant thickness for at least a portion (2 to 4 inches, for a non-limiting example) of the pocket engaging end. Applicants have discovered, however, that the use of a varied thickness at the first end limb provides unexpected advantages. Specifically, the varied thickness provides limbs that can withstand greater bending forces prior to failing under load and reduced vibrations. The position of the hinge point HP to respect to the first end  60  of the limb  36  can be any position chosen with sound judgment by a person of ordinary skill in the art. In one embodiment, shown in  FIG. 6 , the hinge point HP is at least 6 inches from the first end  60  of the limb  36 . It should also be noted that the pockets  42  were not modified. Thus, it is clear that the varied thickness limbs provide the advantage. As a result, the limb length L 1  can be shorter than previously thought possible. This also may contribute to the reduced ratio WD/PD described above. In one embodiment, the limb length L 1  may be less than 15 inches. In a more specific embodiment, the limb length L 1  may be less than 13 inches. In yet a more specific embodiment, shown in  FIG. 6 , the limb length L 1  maybe about 12 inches. In yet a more specific embodiment, the limb length L 1  maybe about 11 inches, the distance between the two pivot axis WD may be about 17.5 inches uncocked and about 13 inches when cocked. For this embodiment, the power stroke distance PD may be about 12 inches or greater. 
     With continued reference now to  FIGS. 1-6 , each limb  36  may substantially completely comprise a composite carbon fiber. The composite carbon fiber may provide each limb  36 , and therefore the crossbow  10 , with a reduced weight. In one embodiment, the composite carbon fiber limb  36  may have a reduced weight relative to a conventional limb thereby resulting in a lighter weight crossbow. The composite carbon fiber limb  36  may also cause a greater attenuation of sound and vibration when firing the crossbow  10 . Each composite carbon fiber limb  36  may be pre-engineered and may consist at least partially of actual carbon fibers. Each composite carbon fiber limb  36  may include a decorative design applied thereon. The decorative design may comprise a camouflage pattern that at least partially provides a camouflaged appearance to the crossbow  10  that at increases the user&#39;s ability to remain undetected while hunting game, such as, for example, deer. In one embodiment, the decorative design may comprise an epoxy outer layer that is applied over each composite carbon fiber limb  36  during the manufacturing process. In another embodiment, the decorative design may be painted onto the limbs  36  using other methods known in the art. 
     With reference now to  FIGS. 2 and 5 , in another embodiment each pocket  42  has first and second portions  42   a,    42   b.  Each of these portions  42   a,    42   b  receives a separate limb  36 . In this way, the crossbow  10  may use dual limbs on each end of the riser  40 . It should be noted that these inventive limb designs are not only applicable to a crossbow but would also apply to a compound bow or other bows when applied with sound judgment by a person of ordinary skill in the art. 
     With reference now to  FIGS. 1-4 and 7-12 , a riser design according to one embodiment will now be described. The riser  40  may have a first end  64  with one pocket  42  and a second end  66  with another pocket  42 . The riser  40  may also include a connection portion  68  for use in connecting the riser  40  to the first end  11  of the main beam  12 . The connection portion  68  may be connected to the main beam  12  in any manner chosen with sound judgment by a person of ordinary skill in the art, such as, for example, using bolts. The riser  40  may include one or more cutouts  70  in order to minimize the riser materials required while still providing sufficient strength. In one embodiment, the riser  40  may substantially completely comprise a composite carbon fiber. The composite carbon fiber may provide the riser  40 , and therefore the crossbow  10 , with a reduced weight. The composite carbon fiber of the riser  40  may also cause a greater attenuation of sound and vibration when firing the crossbow  10 . The composite carbon fiber riser  40  may be pre-engineered and may consist at least partially of actual carbon fibers. The composite carbon fiber riser  40  may include a decorative design applied thereon. The decorative design may comprise a camouflage pattern that at least partially provides a camouflaged appearance to the crossbow  10  that at increases the user&#39;s ability to remain undetected while hunting game, such as, for example, deer. In one embodiment, the decorative design may comprise an epoxy outer layer that is applied over the composite carbon fiber riser  40  during the manufacturing process. In another embodiment, the decorative design may be painted onto the composite carbon fiber riser  40  using other methods known in the art. 
     With continued reference now to  FIGS. 1-4 and 7-12 , an opening  72  may be formed in the riser  40  and may define a foot stirrup  74  which is used, as is well known, in cocking the crossbow  10 . In one embodiment, the opening  72  is positioned at least partially directly between the pockets  42 ,  42 . This arrangement provides an opening  72  sufficient to receive most boot sizes yet simultaneously provides a reduced overall length for the crossbow  10  making it easier to manually cock the bowstring  34 . In another embodiment, the pockets  42 ,  42  extend at least partially longitudinally beyond the first end of  11  off the main beam  12 . This arrangement also provides for an overall reduced length for the crossbow  10 . In yet another embodiment, the foot stirrup  74  is made with the riser  40  as a single piece. This permits, for one non-limiting example, the riser  40  and the foot stirrup  74  to be machined from a single piece of material. In one embodiment, the foot stirrup  74  comprises a generally U-shaped member extending from the riser body. The U-shaped member has a pair of leg portions  110 ,  110  and a mid-portion  112 . The mid-portion  112  has an outer surface  114  that is substantially planar and is used in contacting a ground surface (as shown in  FIG. 8 ) when cocking the crossbow  10 . The mid-portion  112  in one embodiment is on the same plane as the leg portions  110 ,  110 . In another embodiment, shown, the mid-portion  112  has an offset  116 . This offset  116  permits the crossbow  10  to be easily balanced on a ground surface when a user is cocking the crossbow  10 . As shown in  FIGS. 11-12 , the offset  116  may extend downwardly. In one embodiment, the leg portions  110 ,  110  extend substantially perpendicular from an inner surface of the mid-portion  112 . In another embodiment, shown in  FIG. 12 , each leg portion  110  has an offset  118  that may extend outwardly. This offset  118  permits the opening  72  to be larger to thereby receive a user&#39;s foot that is larger and also provides for a longer mid-portion  112  that assists in balancing the crossbow  10  to a ground surface. It should be noted that this inventive riser design is not only applicable to a crossbow having a compound bow but also to a crossbow having other bows when applied with sound judgment by a person of ordinary skill in the art. 
     With reference now to  FIGS. 1-4 and 13-20 , a wheel design according to one embodiment will now be described. The wheel  38  may have first and second sides  82 ,  84  and an opening  86  (referenced in  FIG. 16 ). The opening  86  is used to receive a shaft  88  that is operatively connected to the limbs  36  of the crossbow  10 . The wheel  38  may then rotate about the shaft  88  any manner chosen with sound judgment by a person of ordinary skill in the art. Rather than having the wheel opening  86  rotate directly around the shaft  88  as is commonly known, at least one bushing  90  may be used. The bushing  90 , as seen in best in  FIG. 17 , may have an opening  92  that rotatably receives the shaft  88 . The bushing  90  may also have a first end  94  that is received within the opening  86  in the wheel  38  and a second end  96  that has a flange  100 . The flange  100  has an outer diameter that is greater than the outer diameter of the first end  94 . As a result, the flange  100  contacts the first side  82  of the wheel  38 . It is to be understood, however, that the outer shape of the bushing  90  need not be circular in cross-section, as shown, but could have other shapes. In another embodiment, a second bushing  90  may be inserted into the opposite end of the wheel opening  86 . In this case, the flange  100  contacts the second side  84  of the wheel  38 . In still another embodiment, there is a space  102  between the first end  94  of one bushing  90  and the first end  94  of the other bushing  90  when they are properly installed onto the wheel  38 . For the embodiments shown, each wheel  38  comprises a pair of pulleys and comprises a cam. It should be understood, however, that the bushings described herein will work with wheels having any number of pulleys and wheels that may or may not comprise a cam. It should be noted that this inventive wheel design is not only applicable to a crossbow but would also apply to a compound bow when applied with sound judgment by a person of ordinary skill in the art. 
       FIG. 21  illustrates an example graph  2100  of a crossbow&#39;s draw weight to power stroke data, illustrating a resulting power curve  2102 . In this example graph  2100 , the draw weight of a crossbow is represented by the ‘Y’ axis  2104  and the power stroke (e.g., power distance (PD)) of the crossbow is represented by the ‘X’ axis  2106 . Further, in this example, the draw weight  2104  comprises units in pounds (lbs), and the power stroke  2106  comprises units in inches (in). As an example, the data used to generate the plot of the power curve  2102  is derived from experimental data for a given crossbow; however, different data may be derived from a different crossbow, such as one comprising different materials and/or configurations. The following table 1 represents the power stroke to draw weight plots indicated by the example graph  2100  for the given crossbow: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Draw Weight to Power Stroke data. 
               
            
           
           
               
               
               
            
               
                   
                 Power Stroke (PD) in inches 
                 Draw Weight in pounds 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 1 
                 43.5 
               
               
                   
                 2 
                 75.7 
               
               
                   
                 3 
                 111.4 
               
               
                   
                 4 
                 139.7 
               
               
                   
                 5 
                 166.4 
               
               
                   
                 6 
                 181.5 
               
               
                   
                 7 
                 185 
               
               
                   
                 8 
                 179.6 
               
               
                   
                 9 
                 166.3 
               
               
                   
                 10 
                 147.4 
               
               
                   
                 11 
                 122.7 
               
               
                   
                 12 
                 103.4 
               
               
                   
                 13 
                 87.7 
               
               
                   
                 14 
                 89.4 
               
               
                   
                   
               
            
           
         
       
     
     Further, when given data regarding power stroke (PD) and data for wheel distance (WD) to PD ratios (WD/PD), a wheel distance for the given data can be calculated as, WD=(PD)(WD/PD). Table 2 below illustrates potential WD values that may be calculated using various combinations of values described above: 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Wheel Distance (WD) values based on 
               
               
                 known WD/PD ratios and known PD data. 
               
            
           
           
               
               
               
               
            
               
                   
                 PD = 10 
                 PD = 12 
                 PD = 13 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 WD/PD &lt; 2.0 
                 WD &lt; 20.0 
                 WD &lt; 24.0 
                 WD &lt; 26.0 
               
               
                   
                 WD/PD &lt; 1.8 
                 WD &lt; 18.0 
                 WD &lt; 21.6 
                 WD &lt; 23.4 
               
               
                   
                 WD/PD &lt; 1.6 
                 WD &lt; 16.0 
                 WD &lt; 19.2 
                 WD &lt; 20.8 
               
               
                   
                   
               
            
           
         
       
     
     Based on the forgoing, in one implementation, as illustrated in Table 2, when the WD is less than 26, in any of the example WD/PD ratios, the PD is 13 or less. Further, in this implementation, as illustrated in Table 1, when the PD is 13 the draw weight may be greater than eighty-seven pounds. 
     The word “exemplary” is used herein to mean serving as an example, instance or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Further, at least one of A and B and/or the like generally means A or B or both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims may generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of the claimed subject matter. 
     Also, although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The disclosure includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the disclosure. 
     In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” 
     The implementations have been described, hereinabove. It will be apparent to those skilled in the art that the above methods and apparatuses may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.