Abstract:
B/D archery bow accessories which have an elastomeric vibration dampening component mounted on an elongated, rigid support. The elastomeric component has a set of integral vibration dampening elements such as ribs. The vibration dampening elements have irregular profile configurations which make these elements capable of dampening with high efficiency the sets of vibrational frequencies generated: (a) when an arrow is shot, and (b) during and after the ensuing lock-up. Vibration dampening efficiency may be promoted by making the elastomeric component from a material of the most optimal hardness that is practical and by employing end pieces at opposite ends of the elastomeric component.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to novel, improved accessories for archery bows and, more particularly, to novel improved accessories for balancing a bow and dampening vibrations: (a) when an arrow is shot from the bow, and (b) during and after the subsequent lock-up. 
     DEFINITIONS 
     Vibration: includes: (a) shocks and vibrations with frequencies: (1) in the audible range, and (2) higher and lower than those in the audible range, and (b) shocks and vibrations with the different amplitudes present in any particular frequency spectrum. 
     B/D Accessory: an archery bow accessory with the capabilities of balancing a bow and dampening vibrations generated when an arrow is shot from the bow. 
     Lock-up: that period extending from the time the bow string is released to shoot an arrow to the time that the arrow leaves the bow. 
     BACKGROUND OF THE INVENTION 
     When an arrow is shot from an archery bow, from 10 to 25% of the energy generated when the bow string is released remains in the bow. This energy can adversely affect the accuracy of the shot. Also, the residual energy generates significant vibration. Transmission of the vibration to the shooter&#39;s hand causes discomfort and can cause the shooter to flinch, reducing the accuracy of, or entirely spoiling, the shot. The sound of the shot can also elicit an unwanted reaction from the shooter and, if the shooter is a hunter, can frighten the intended target, causing it to suddenly move, again spoiling the shot. Numerous factors and energies contribute to the vibration and to the feel of the bow when an arrow is shot. Representative of these factors are: string oscillation, limb spring, riser flex, etc. 
     Stabilizers have for a long time been employed to reduce an adverse influence on the balance of a bow when an arrow is shot from the bow and, after the shot, during the lock-up time; i.e., the time while the arrow is still in the bow. Balance is extremely important; the more balanced the bow, the easier it is to stay on target while aiming the bow. 
     Typically, these stabilizers are long, rodlike or comparable devices which extend well in front of the bow and are mounted to the riser of a compound bow or comparable component of a recurve or other bow to reduce movement of the bow when the arrow is shot. 
     Later developed bow stabilizers may be mounted to the bow with the additional goal of reducing vibration and improving the feel of the bow by aggressive attenuation of energy. One type of bow stabilizer with vibration reducing capabilities employs an elastomeric component to rapidly reduce vibration energies by visco-elastic resistance. A superior, commercially available bow stabilizer of this type is illustrated in  FIG. 1  and identified by reference character  20 . 
     Stabilizer  20  has a series  22  of integral, annular ribs  24   a  . . .  24   g  with uniformly circular peripheries. Ribs  24   a  . . .  24   g  are separated by integral stems. A representative stem is identified by reference character  26 . Ribs  24   a . . . g  are located between an integral, stemmed, mushroom-shaped end member  30  and an integral, frustoconical end member  32 . The vibrational are complex Ribs  24   a  . . .  24   g  effectively reduce these motions because they have multiple degrees of freedom which allow them to move universally; i.e., in any direction in a 360° (spherical) pattern. 
     Another, heretofore proposed bow stabilizer with an elastomeric, “energy dispersion” component is shown in FIGS. 4, 7, and 8 of U.S. Pat. No. 6,802,307 to Levin. The Levin devices are unnecessarily complex and less efficient than the type of bow stabilizer illustrated in  FIG. 1  and, to the extent that they do appreciably dampen vibrations, do so in only a very narrow frequency range. The elastomeric component of a Levin device is a rubber knuckle which houses a stabilizer weight. It is the oscillation of this weight, not the visco-elastic resistance of integral, elastomeric stabilizer elements which is relied upon to reduce vibration when an arrow is shot from a bow equipped with a Levin device. 
     Yet another prior art stabilizer with an elastomeric component, though one of significantly different construction, is the NAP Blackjack illustrated at: http://www.cabelas.com/prod-1/0039028417438a.shtml and http://www.keystonecountrystore.com/NAP_Stabilizer.html. This complicated device is said to reduce recoil and dampen sound when an arrow is shot from a bow due to the provision of “energy fins” on a sleeve. 
     SUMMARY OF THE INVENTION 
     Superficially, the novel, improved bow B/D accessories disclosed herein resemble prior art stabilizer  20  in that they have an elastomeric component which includes a set of axially aligned, annual ribs separated by integral stems and embraced by integral end pieces 
     However, the B/D accessories of the present invention are, significantly more effective in reducing vibration than the  FIG. 1  type stabilizer  20 , and they work effectively with a significantly wider variety of bows than prior art, stabilizer type devices and are as effective as those devices as far as the balancing of a bow is concerned. The increase in efficiency is attributable in large part to a rib configuration which has a margin-defining edge with an irregular profile or, stated otherwise, a margin-defining edge which has a variable height relative to the axial centerline of the elastomeric component. 
     The rib configurations of the present invention as described in the preceding paragraph produce ribs having a relatively stiff inner segment which efficiently dampens vibrations (including shock and sound) that have a high frequency and a more flexible outer segment which efficiently dampens vibrations which lower frequencies. 
     In these inner and outer regions or segments of the rib, vibrations are dampened by oscillation, fore-and-aft and side-to-side bending, elongation, twisting, contraction, rippling, flopping, and other distortions of the elastomeric material. These motions of the elastomeric B/D accessory components, as a class, are identified herein by the judicially approved and construed term “wiggle and jiggle”. The rib configurations of the present invention described above promote, to an important extent, vibration dampening wiggling and jiggling of the elastomeric material because they have multiple operating modes. Specifically, each rib segment of different size and/or shape effectively dampens a particular set of vibrational frequencies or a number of such sets. And the segments are configured to most effectively dampen different sets of vibrational frequencies such that all of the frequencies in a target spectrum are efficiently dampened. 
     The feature, advantages, and objects of the present invention will be apparent to the reader from the foregoing, the claims, and the ensuing detailed description of the invention taken in conjunction with the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a prior art archery bow stabilizer; 
         FIG. 2  is a perspective view of an archery bow equipped with an archery bow B/D accessory which embodies and is constructed in accord with the principles of the present invention; 
         FIG. 3  an enlarged scale fragment of  FIG. 2 ; 
         FIG. 4  is a fragmentary exploded view showing how the B/D accessory is attached to the bow; 
         FIG. 5  is a longitudinal section through the B/D accessory, taken substantially along line  5 - 5  of  FIG. 3 ; 
         FIG. 6  is an enlarged scale transverse section through the B/D accessory, taken substantially along line  6 - 6  of  FIG. 5 ; and 
         FIG. 7  is a fragment of  FIG. 5  drawn to an enlarged scale to better show representative rib and stem elements of an elastomeric component of the  FIG. 1  B/D accessory. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings,  FIG. 2  depicts a compound archery bow  40  of the character disclosed in previously filed application Ser. No. 12/287,506, which has a filing date of 9 Oct. 2008 and is hereby, in its entirety, incorporated in this specification. An arrow  42  is flocked to bow string  44 , and the bow is equipped with a B/D accessory  46  embodying, and constructed in accord with, the principles of the present invention. 
     Bow  40  has a riser  48  and upper and lower limbs  50  and  52  mounted to riser  48  in articulated limb pockets  54  and  56 . Rotatable, axle-mounted cams  58  and  60  are mounted to the tips of upper and lower limbs  50  and  52 . Buss/control cables collectively identified by reference character  62  and the aforementioned bow string  44  are strung between upper and lower cams  58  and  60  with the buss/control cables  62  being trained through a riser-mounted cable guide  64 . 
     Details of the bow  40  just described appear in the above-cited &#39;506 application. 
     Referring still to  FIG. 2 , but also to  FIGS. 3-7 , B/D bow accessory  46  has an axial line of symmetry  65  (see  FIG. 5 ) and an elastomeric component  66  mounted on, and surrounding, an elongated, rigid member  68 . B/D accessory  46  is mounted to the riser  48  of bow  40  by an externally threaded, integral end segment  70  of rigid component  68  (see  FIG. 4 ). This segment is threaded into a complementary, internally threaded hole  72  in the front side of riser  48 . Flats on rigid member  68  adjacent threaded end segment  70  accommodate a wrench if one is employed to tighten the rigid member  68  after its end segment  70  is threaded into riser hole  72 . A representative one of these flats is identified by reference character  74  in  FIG. 3 . 
     The elastomeric component  66  of representative B/D accessory  46  has a set  76  of integral, annular; vibration dampening elements. In accessory  46 , these elements are ribs  78 . Six of these ribs are divided into two subsets  80  and  82  disposed in mirror image-relationship on opposite sides of a central rib  78   d . Subset  80  contains ribs  78   a - 78   c , and subset  82  contains ribs  78   e - 78   g . From outer to inner end, the ribs in each set increase in thickness with ribs  78   b  and  78   f  being thicker than ribs  78   a  and  78   g  and ribs  78   c  and  78   e  being thicker than the adjacent ribs  78   b  and  78   f . The central rib  78   d  is thicker than the adjacent ribs  78   c  and  78   e  in rib subsets  80  and  82 . 
     Each of the ribs  78   a - 78   g  is separated from its neighbor by an annular, associated and integral, longitudinally-extending stem. One of these stems is shown most clearly in  FIG. 7  and identified by reference character  84 . A like stem  86  separates the seventh annular rib  78   g  from an integral, frustoconical, end component  87  of elastomeric B/D accessory component  66 . The end number  87  of B/D accessory  46  and each of the seven head/stem units such as  78   a / 84  function, in this respect, in a manner akin to that of the damping devices disclosed in the above-cited &#39;046 patent 
     At the opposite end of the elastomeric component  66  of B/D bow accessory  46  is a second, also integral, mushroom-shaped end member  88 . This component has an annular head  90  and a longitudinally oriented stem  92  which extends from the head to annular rib  78   a.    
     End members  87  and  88  and the combination of ribs  78   a - 78   g  and integral stems such as that identified by reference character  84  ( FIG. 7 ) rapidly, and efficiently, reduce vibration energies via visco-elastic resistance when arrow  42  is shot from bow  40 . The effect of frustoconical end member  87 , mushroom-shaped end member  88 , and each of the rib/stem units such as the one made up of rib  78   a  and stem  84  is cumulative, resulting in B/D device  46  being appreciably more effective than a dampening device such as one of those dampening devices shown in FIGS. 2 and 7 of the &#39;046 patent, for example. 
     An important feature of B/D bow accessory  46  is that each of the seven annular ribs  78   a - 78   g  has a margin-defining edge with an irregular profile which divides the rib into regions with different sizes and/or shapes. In this instance the profile has a variable height relative to the axial centerline of the accessory component  66  as is preferred in the practice of the present invention. Specifically, each of the ribs  78   a - 78   g  of the representative B/D accessory  46  illustrated in  FIGS. 2-7  has a cruciform external configuration defined by cutouts such as those identified by reference characters  94   a - 94   d  spaced around the periphery of the rib (see  FIGS. 3 and 6 ). In representative B/D accessory  46 , these cutouts are scallops, but this particular configuration is not essential; and cutouts with other configurations and/or spaced unequally around the rib may prove superior in other embodiments of the invention. 
     The scallops, which extend only part way to the rib-associated stems such as  84 , provide in each rib protrusions  93   a - 93   d  with convex external surfaces such as the one identified by reference character  95   a  in  FIG. 6 . The scallops d  94   a - 94   d  have concave exterior surfaces, one of these being identified by reference character  95   b.    
     Thus, each of the ribs  78   a - 78   g  of B/D accessory  46  meets the requirement that it have an irregular profile and, further, satisfies the strong preference for a rib which has a variable height relative to the axial centerline of the elastomeric accessory component  66 . In particular, each of the ribs  78   a - 78   g  varies in height from a minimum height h 1  relative to the axial centerline  65  of the B/D accessory  46  to a maximum height h 2  relative to that centerline (see  FIG. 6 ). As discussed above this produces an inner rib region  95   c  and outer rib regions such as  95   d  ( FIG. 6 ) which are relatively stiff and flexible, respectively; which have different sizes and shapes; and which therefore provide optimal, multimode dampening of high frequency and low frequency vibrations. 
     While equiangular spacing of the scallops is employed in representative B/D accessory  46 , and while all of the scallops are of the same size and shape as are the ribs (except for thickness), this is not a requirement of the invention. Variations such as ribs of different sizes and shapes and/or scallops which likewise vary in size and/or shape and/or are spaced at other than equiangular distances may equally well be employed in other embodiments of the present invention. Also, as stated above, cutouts of any other appropriate shape may be employed instead of scallops. 
     As shown  FIG. 3 , the head  90  of representative elastomeric component end member  88  and the frustoconical end member  87  of that component also have symmetric, cruciform configurations of the same character as ribs  78   a - 78   g . Reference characters  96  and  98  in  FIG. 3  identify a convex protrusion and a concave scallop  98  of end member head  90 , and reference characters  100  and  102 , respectively identify a protrusion and a scallop of elastomeric component end member  87 . However, in other applications of the invention, either or both of the end members  87  and  88  may have a different irregular profile configuration; and the cross-sectional configuration of the end member(s) may not be symmetrical. 
     Each of the B/D bow accessory ribs  78   a - 78   g , the head  90  of mushroom-shaped end member  88 , and the frustoconical end member head has four quadrants, each having a protrusion  93   a - 93   d  as an active element. The quadrants of one rib are identified in  FIG. 6  by reference characters  104   a - 104   d ; and exemplary quadrants of head  90  and end member  87  are identified in  FIGS. 3 and 4  respectively by reference characters  106  and  108 . 
     Each of the rib quadrants and the mushroom-shaped and frustoconical end members can wiggle and jiggle independently. Each rib quadrant, the frustoconical end member, and the head and stem of the mushroom-shaped end member can therefore independently dampen vibration energies in multiple, different (though perhaps overlapping) sets of vibrational frequencies and amplitudes; and the effects of these independent actions are cumulative. The result of this multi-mode method of operation is that vibrations, are dampened at a significantly higher rate than has heretofore been achieved, resulting in a quieter shot, a smoother feel, significantly reduced movement of the bow when an arrow is shot and during and after lock-up, and an all-around better experience for the shooter because, as suggested above, the foregoing elements have maximum vibration dampening efficiencies with respect to different ones of the vibrational frequency sets in a spectrum of frequencies generated when an arrow is shot. 
     Vibration dampening efficiency is further promoted by optimizing the hardness of the elastomeric material from which the elastomeric component  66  of B/D accessory  46  is fabricated. Appropriate materials are those in the Sims Vibration Laboratory NAVCOM® family of elastomers. Optimum hardnesses are those in the Durometer A range of 7-40 Elastomeric B/D accessory components as disclosed herein are made from NAVCOM® materials having a hardness in the 12 to 20 Durometer range. 
     A B/D bow accessory such as the one discussed above and illustrated in  FIGS. 2-7  has, in this regard, been found more effective in mitigating the effects of shock, vibration, and sound energies than the prior art bow stabilizer  20  illustrated in  FIG. 1 , the prior art bow stabilizers disclosed in the above-cited &#39;307 patent, and the stabilizer disclosed in the above-cited Cabela&#39;s and Keystone Country Store websites. 
     The principles of the present invention may be embodied in forms other than the one specifically disclosed herein. A number of alternate forms are identified above. As further examples, for optimum efficiency in a particular application of the invention it is not necessary and may even be preferred that the ribs or comparable elements of the B/D device have an asymmetrical configuration rather than the symmetric configuration described above. Ribs or comparable elements of B/D devices optimized for particular applications of the invention may not be arranged in mirror image sets as in the embodiment of the invention disclosed herein or have the pattern of increasing thicknesses or generally uniform spacing of the ribs also disclosed herein, and a different method of supporting the ribs or the like from the rigid member of the device may be employed as may any of the alternate features identified above in this specification and still other features within the purview of the present invention. Therefore, the present embodiment is to be considered in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.