Abstract:
Devices for modifying the decay pattern of shock and vibrations set up in a bow when an arrow is released to thereby reduce bow jump and the level of sound. Those devices are fabricated in part from an elastomeric material which flexes and stretches to attenuate vibrations reaching the component. An element of the distortoring elastomeric component so touches the bow as to further dampen the vibrations with a consequent reduction in sound and bow jump.

Description:
CROSS REFERENCE TO ANOTHER APPLICATION  
       [0001]    This application is entitled to, and claims the priority of a U.S. provisional patent application No. 60/332,498 filed Nov. 15, 2001. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The present invention relates in one respect to archery bows and a more particularly, to novel accessories which improve accuracy of such bows by modifying the decay pattern of the shock and sound vibrations set up in the bow when an arrow is released.  
         BACKGROUND OF INVENTION  
         [0003]    The release of an arrow from even a modern bow sets up significant shock waves and vibrations in the limbs of the bow, and these are in large part transmitted to the riser of the bow and from there to the archer&#39;s hand. The result is a significant adverse effect on accuracy. Also, a significant fraction of these vibrations are in the audible range. The sound is loud enough to frighten an animal and thereby deprive a hunter of a second shot.  
           [0004]    A variety of accessories have been employed (or proposed) in an effort to reduce the adverse effect of shock and vibration on the accuracy of the bow. At best, such devices have proved to be of limited value.  
           [0005]    The exception is those vibration decay pattern modifiers disclosed in U.S. Pat. No. 6,298,842 issued Oct. 9, 2001 to Sims. These patented accessories significantly reduce the adverse effect on accuracy of the shock and vibration generated when an arrow is released. They also significantly reduce the level of the sound generated when an arrow is released. Different ones of these decay pattern modifiers are fixed to the limbs of the bow and/or to the end of the stabilizer typically attached to the riser of a compound bow.  
           [0006]    Decay pattern modifiers as disclosed in the 6,298,842 patent are fabricated from an elastomeric polymer and have a configuration such that the modifier can inter alia, vibrate or oscillate toward and away from the longitudinal axis of the modifier and can oscillate in directions generally parallel to the longitudinal modifier axis. Flex and stretch motions are also set up in the material of the damper. The combined result of these motions is a wiggle and jiggle effect which significantly alters the decay pattern of shock and vibrations set up in the bow when an arrow is released, effectively minimizing bow jump and reducing sound levels.  
           [0007]    Yet another, particularly important advantage of the patented invention is that there is only a small, two foot per second (typical) loss in arrow velocity appurtenant to the use of decay pattern modifiers embodying its principles.  
           [0008]    Another important attribute of the patented decay pattern modifiers is that they are light and small enough that they do not interfere with the normal drawing of the bow string and subsequent release of an arrow.  
         SUMMARY OF THE INVENTION  
         [0009]    There have now been invented and disclosed herein certain decay pattern modifying accessories which even further reduce bow jump and sound level when an arrow is released from an archery bow. These accessories are designed to be mounted to the limbs of a split limb or solid limb bow or to the limbs of a recurve or other archery bow.  
           [0010]    The accessories disclosed herein are in certain respects improvements over those disclosed in the 6,298,842 patent. These new accessories have a component fabricated from an elastomeric material, and the elastomeric component is mounted to the bow limb by way of a generally rigid mounting component which transmits shock and sound waves from the bow limb to the elastomeric material. The new accessories have a “two-step” mode of operation. In the first step, the accessory flexes and stretches and otherwise distorts (i.e. wiggles and jiggles) to modify the decay pattern of the vibrations set up in the limbs of the bow when an arrow is released such that bow jump and noise are significantly released.  
           [0011]    In the second step of the dampening process, an element of the elastomeric component touches the limb of the bow to which the decay pattern modifier is mounted. This provides a second level of bow jump and sound dampening in much the same manner that the sound of a bell is muted by touching it with one&#39;s finger.  
           [0012]    As this restoration step proceeds, an integral element of the elastomeric accessory component acts as a dampener, further reducing audible sound and shock vibrations in much the same manner that a finger touched to a ringing bell reduces the sound level of the bell and the duration of the period for which the sound is audible.  
           [0013]    The result of the two steps described above is significantly improved performance in terms of bow jump and sound reduction.  
           [0014]    Another significant difference between the vibration pattern modifying accessories disclosed herein and those disclosed in the 6,298,842 patent is that the former have a lower profile. This makes it less likely that the bow to which they are attached will snag on brush or clothing or the like.  
           [0015]    Also, the accessories disclosed herein have a longer service life and are less susceptible to failure.  
           [0016]    In addition, the novel accessories of the present invention have all of the features and advantages of those accessories disclosed in the 6,298,842 patent.  
           [0017]    The objects, advantages, and features of the present invention will be apparent ot the reader from the foregoing and the appended claims and from the ensuing description and discussion of the invention, taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is a fragmentary and pictorial view of a solid limb compound bow equipped with a shock and sound dampening accessory embodying the principles of the present invention; the accessory is mounted to the inner side of the limb;  
         [0019]    [0019]FIG. 2 is an exploded view showing the components of the FIG. 1 accessory: viz., an elastomeric component, a generally rigid attachment plate, and a peel away cover for an adhesive coating on the side of the mounting plate component opposite from the elastomeric component;  
         [0020]    [0020]FIG. 3 is a perspective view of the elastomeric accessory component;  
         [0021]    [0021]FIG. 4 is a section through the FIG. 1 accessory with the cover partly peeled away from the adhesive;  
         [0022]    [0022]FIG. 4A is a view showing, pictorially, one of the many paths of deflection the elastomeric component of a decay pattern modifier embodying the principles of the invention may take in dampening vibrations in accord with the principles of the present invention.  
         [0023]    [0023]FIGS. 4B and 4C are side views of, respectively, a prior art decay pattern modifier and a decay pattern modifier as disclosed herin; a comparison of the two figures show the desirability lower profile of the decay pattern modifiers disclosed herein;  
         [0024]    [0024]FIG. 5 is a fragmentary and pictorial view of: a split limb compound bow and a second specie of shock and sound reducing accessory which embodies the principles of the present invention and is mounted to the inner (string) side of the bow limb;  
         [0025]    [0025]FIG. 6 is a view similar to FIG. 5 but looking at the outer side of the bow and showing one of the accessory&#39;s two rigid mounting components. The bow limb is clamped between this component and the second rigid mounting component (see FIG. 5) by a threaded fastener for drawing the mounting plates toward each other to mount the accessory to the bow limb;  
         [0026]    [0026]FIG. 7 is a cross-section through the accessory of FIG. 5 as assembled to the bow limb; the components of the accessory as shown in FIG. 7 are: the two rigid accessory mounting components and fastener discussed above, and a shock and sound reducing elastomeric component; that component is permanently attached to the second of the mounting components;  
         [0027]    [0027]FIG. 8 is an exploded view of the FIG. 5 accessory;  
         [0028]    [0028]FIG. 9 is a graph showing the decay pattern of the shock wave transmitted to the limb of a Darton Mav Twin Cam 27-31 compound bow when an arrow is released;  
         [0029]    [0029]FIG. 10 is a graph like FIG. 8; in this case the bow was equipped with decay pattern modifiers as described in the 6,298,842 patent;  
         [0030]    [0030]FIG. 11 is a graph like FIG. 8; in this case the bow was equipped with decay pattern modifiers embodying the principles of the present invention;  
         [0031]    [0031]FIG. 12 is a graph showing the decay pattern of the sound generated when an arrow was released from a Bear compound bow;  
         [0032]    [0032]FIG. 13 is a graph like FIG. 11 but showing the sound decay pattern when the arrow was released from the Bear bow equipped with decay pattern modifiers as disclosed in the 6,298,842 patent; and  
         [0033]    [0033]FIG. 14 is a graph like FIG. 11 but showing the sound decay pattern when an arrow was released from the Bear bow equipped with decay pattern modifiers embodying the principles of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]    Referring now to the drawing, FIG. 1 depicts, in fragmentary form, a bow  20  equipped with vibration decay pattern modifiers constructed and operating in accord with the principals of the present invention. Bow  20  has the customary, flexible limbs mounted to opposite ends of a riser  22 . One of these limbs is shown in FIG. 1 and identified by reference character  24 . Bow  20  also has a bow string  26  trained around cams rotatably mounted at those ends of the limbs opposite riser  22 . Only the cam mounted to limb  24  is shown in FIG. 1. That cam is identified by reference character  28 .  
         [0035]    Referring still to FIG. 1, the decay pattern modifier attached to bow limb  24  is identified in FIG. 1 by reference character  30 . Referring now to more specifically, to FIGS.  2 - 4 , decay pattern modifier  30  has two components—an elastomeric, decay pattern modifying, component  34  and a rigid plate  36  for attaching the elastomeric component to the limb of a bow. The particular decay pattern modifying component of FIGS.  1 - 4  is designed to be mounted a bow limb of the solid type, and the bow limb  24  depicted in FIG. 1 is of that type.  
         [0036]    The second, mounting component  36  of decay pattern modifier  30  is fixed in any convenient manner to the end  38  of elastomeric decay pattern modifier component  34 . Component  36  is employed to mount the decay pattern modifier to the limb of a bow and is fabricated from a material with sufficient flexibility to conform to the contour of the limb surface to which it is fixed. In the exemplary application of the invention under discussion, this is the surface  40  of the bow limb  24  illustrated in FIG. 1.  
         [0037]    Mounting component  36  is adhesively, or otherwise, firmly fixed to end  42  of modifier component  34  as is best shown in FIGS. 2 and 3. The exposed side  46  of component  36  is coated with an adhesive  48  protected by a peel off covering  50 . This makes the attachment of the decay pattern modifier to the associated limb of bow  20  of the utmost simplicity. All that is required is the removal of protective cover  50  and the subsequent pressing of the decay pattern modifier onto the limb of the bow at the selected location there along.  
         [0038]    In this regard, decay pattern modifiers such as the one identified by reference character  30  are preferably located near the outer ends of the bow limbs to which they are attached. The placing of the decay pattern modifiers at these locations has been found to be the most effective in mitigating the effects of shock and vibrations set up in bow  20  when an arrow is released.  
         [0039]    It is also preferred that the decay pattern modifiers be mounted on the inner faces—such as  40 —of the bow limbs to which they are affixed. This keeps the modifiers from being snagged as a bowman moves through brush or bushes, for example. Significant, worthwhile modification in the vibration decay patterns set up in the bow limbs when an arrow is released can nevertheless be obtained by mounting the decay pattern modifiers on the opposite, outer faces of the bow limbs.  
         [0040]    Another deleterious phenomenon occurring when an arrow is released is the generation of unwanted sound. This is many times loud enough to scare away an animal being hunted, precluding the possibility of a second shot, leading to the often onerous task of tracking down a wounded animal. The level of the sound generated by an arrow released from a BEAR company compound bow with no vibration decay pattern modifiers is shown in FIG. 12. FIG. 13 shows that a significant, worthwhile reduction in the sound level can be obtained by adding to the BEAR bow, decay pattern modifiers as disclosed in the 6,298,842 patent, and FIG. 14 shows that an even greater reduction in sound level can be obtained by substituting decay pattern modifiers as disclosed herein for those of the just referred to patent.  
         [0041]    Referring still to the drawing, FIGS.  5 - 8  depict a second decay pattern modifier  60  designed so that it can be readily assembled to the limbs (such as the illustrated limb  62 ) of a split limb bow.  
         [0042]    Decay pattern modifier  60  has an elastomeric component  64  of the character described above, and modifier mounting components or fittings  66  and  68 , which are located on opposite sides of limb  62 . Fittings  66  and  68  are fabricated of a material which is generally rigid but it has sufficient flexibility to conform to the outer and inner surfaces  70  and  72  of the limb. Decay pattern modifier  60  also includes an internally threaded sleeve  74  which is fixed in mount  66  and is extends through the slot  78  between the elements  80  and  82  of limb  62 . An externally threaded, screw like component  84  is seated in an aperture  86  through mounting component  68  and is threaded into the complementary, internally threaded component  74  of the modifier. By rotating component  84 , the mounting components  66  and  68  are drawn together to clamp those components against the opposite sides of limb  62 .  
         [0043]    The illustrated exemplary elastomeric components  34  and  64  are virtual duplicates. Accordingly, only component  34  will be described herein with the understanding that this description is equally applicable to component  64 .  
         [0044]    The  88  elastomeric component  34  has what maybe termed a head  88  and an integral stem  90 . These terms are employed for the sake of convenience and clarity and are not intended to limit the scope of the appended claims except as is expressly called for in those claims.  
         [0045]    “Elastomer” and “elastomeric” are words of art. Elastomers are polymeric materials which can be rapidly stretched to their elastic limit (typically 200-1000 or more percent) and which snap or rebound to their original shape and dimensions when the “stretching” force is removed. Elastomers are thus defined in terms of their physical properties. Elastomeric is the adjective counterpart of, and has essentially the same meaning as, elastomer.  
         [0046]    One suitable material is NAVCOM. NAVCOM is a soft, amorphous, rubber-like elastomer which contains a mixture of chloroprene and butyl polymers. NAVCOM is available from Sims Vibration Laboratory, Shelton, Wash.  
         [0047]    The selected elastomeric material may or may not be viscoelastic. If it is, the response of the material to the imposed load arising from shock and vibration will have both viscous and elastic qualifiers.  
         [0048]    Referring now to FIGS.  2 - 4  and  4 A, integral gussets  92  and  94  extend between the elements  88  and  90  of elastomeric modifier component  32  at locations spaced 180 degrees apart around the circumference of the component.  
         [0049]    [0049]FIG. 4A shows, in stylized form, and by way of arrows  96  and  98  one of the many shock and vibration decay pattern modifying deflection paths  56  elastomeric component  32  may follow when an arrow is released from bow  20  and vibrations are consequently set up in the limb  24  of the bow. As component  34  distorts along this path, the stretching and flexing elastomeric elements  88  and  90  absorb energy and dampen the vibrations. In addition, as the flexing and stretching continues, one and then the other of the integral gusset elements because of rebounding comes into contact with the surface  40  of bow limb  40 . This results in the transfer of additional kinetic energy from the bow limb to the modifier, further, and significantly, contributing to the dampening providing by the decay pattern modifying component.  
         [0050]    Ths terms “shock” and vibration are recognized as closely related distinct phenomena. However, because both shock and vibration are closely related, both will be subsumel under the term vibration as is commonly done here for the sake of conscience and clarity. Both contribute to unwanted bow jump and sound with shock playing the major role in contributing factors in bow jump.  
         [0051]    The vibration dampening efficiency of decay pattern modifiers employing the principles of the present invention are demonstrated by the graphically plotted results of tests of a Darton Mav Twin Cam 27-31 compound bow with: (a) no decay pattern modifiers (FIG. 9); (b) modifiers of the character disclosed in above cited U.S. Pat. No. 6,298,842 (FIG. 10;) and (c) decay pattern modifiers as disclosed herein (FIG. 10). Siginificant dampening and consequent reduction of unwanted phenomena such as bow jump which can cause flinching in terms of initial vibration amplitude and duration of vibration of significant amplitude were realized by employing the patented decay pattern modifiers; additional important gains in terms of initial amplitude and duration of vibrations of consequence were realized by employing the modifier of the present invention. This in much the same manner that the sound of a bell is muted by touching it with one&#39;s finger. The principles of the present invention have a lone been developed in the context of a device designed to reduce bow jump and the sound arising when an arrow is released from a bow. This is by no means the only application of such decay pattern modifiers. They can be fabricated of many sizes and shapes and mounted to other components of a bow or a bow mounted accessory (see e.g., FIGS. 12-14 of the 842 patent) to also reduce the unwanted consequences of arrow release. And, they can be used in countless other applications where the modification of vibration decay and shock patterns is beneficial.  
         [0052]    It will therefore be apparent to the reader that the invention may be embodied in many forms in addition to those disclosed herein without departing from the spirit or essential characteristics of the invention. The present embodiments are therfore to be considered in all respects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description and the drawings, and all changes which come within the meaniing and range of equivalency of the claims are therefore intended to be embraced therein.