Patent Publication Number: US-6910472-B2

Title: Archery bow vibration dampener

Description:
This U.S. patent application is a Continuation patent application of U.S. patent application having Ser. No. 10/035,041, filed on 27 Dec. 2001, now U.S. Pat No. 6,684,874. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a device for dampening vibration and reducing shock in an archery bow. 
   2. Description of Related Art 
   Archery bows typically absorb a great deal of shock and vibration upon release of an arrow. This shock and vibration can cause problems in the field when excess noise is created. 
   The primary mode of movement of a bow limb is normal to the limb surface. After the arrow is launched, the bow limbs snap back and encounter the greatest acceleration of the release process thus resulting in a shock. Often, vibration dampeners vibrate in a symmetric manner, in phase with the bow limb movements and therefore increase shock. This is because: (1) adding dead weight to a bow limb increases adds energy to the rebound of the bow limb and thus the added weight of the dampener on the bow limb increases shock; and (2) when the dampener moves in phase with the bow limb, the mass of the dampener is reactive thus increasing the magnitude of the shock. 
   There exists an apparent need for an effective device for dampening vibration and reducing shock specifically in an archery bow, and generally in any other apparatus which includes an excited surface to which energy is imparted. 
   SUMMARY OF THE INVENTION 
   One object of this invention is to provide a device that dampens vibration and reduces shock imparted to an archery bow upon release of an arrow. 
   Another object of this invention is to provide a device for dampening vibration and reducing shock that includes a peripherally mounted mass at a distal end. 
   The above and other objects of this invention are accomplished with a device that is preferably attached to both bow limbs of an archery bow to reduce vibration and shock imparted to the archery bow when an arrow is released. The device preferably includes a base and a body integrally formed of a flexible material. The base is formed to provide an adequate attachment surface to the archery bow and integrated with a body having a non-uniform cross-section as the body extends away from the base. Preferably, the non-uniform cross-section tapers in a continuously decreasing cross-sectional area as the body approaches the distal end. 
   A peripheral mass is preferably positioned on a portion of the body opposite the base. The peripheral mass preferably comprises perimeter weighting to react out of phase with the bow limb following discharge of arrow. The peripheral mass may include a thickened or increased cross-sectional area for obtaining the necessary perimeter weighting. The peripheral mass may include one or more flanges or tabs positioned at a distal end of the body. 
   The device according to this invention may be applied to the archery bow in a system for reducing vibration and shock. According to this system, two devices are positioned in general axial alignment on either side of a mount that is positioned on each bow limb of the archery bow. The resulting system therefore includes a mount and two devices, one device on a front of the bow limb and one device on a back of the bow limb. 
   Although described in the context of archery bows, the device according to this invention may be applicable generally to any other apparatus that includes an excited surface to which energy is imparted. Examples of such an apparatus include: household appliances such as dishwashers and washing machines, specifically doors and other panels of such household appliances; vehicles, including automobiles and aircraft; engines and motors; and/or any other apparatus wherein vibration and/or shock provide particular detriments to the safe, efficient and/or smooth operation of such apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The technical features of this invention are apparent when the specification is read in view of the drawings, wherein: 
       FIG. 1  is a perspective view of a device for dampening vibration and reducing shock according to one preferred embodiment of this invention; 
       FIG. 2  is a bottom view of the device shown in  FIG. 1 ; 
       FIG. 3  is a side view of the device shown in  FIG. 1 ; 
       FIG. 4  is a top view of the device shown in  FIG. 1 ; 
       FIG. 5  is a sectional side view of the device shown in  FIG. 1  taken along section  5 — 5  of  FIG. 4 ; 
       FIG. 6  is a perspective view of a device for dampening vibration and reducing shock according to one preferred embodiment of this invention; 
       FIG. 7  is a side view of the device shown in  FIG. 6 ; 
       FIG. 8  is a top view of the device shown in  FIG. 6 ; 
       FIG. 9  is a front view of a device similar to the device shown in  FIG. 6 ; 
       FIG. 10  is a perspective view of a device for dampening vibration and reducing shock according to one preferred embodiment of this invention; 
       FIG. 11  is a top view of the device shown in  FIG. 10 ; 
       FIG. 12  is a section side view of the device shown in  FIG. 10  taken along section  12 — 12  of  FIG. 11 ; 
       FIG. 13  is a perspective view of an assembly for dampening vibration and reducing shock according to one preferred embodiment of this invention; 
       FIG. 14  is a side view of the assembly shown in  FIG. 13 ; 
       FIG. 15  is a sectional side view of the assembly shown in  FIG. 13  taken along section  15 — 15  of  FIG. 14 ; 
       FIG. 16  is a side view of an archery bow having a device for dampening vibration and reducing shock according to one preferred embodiment of this invention; 
       FIG. 17  is a side view of an archery bow having a system for dampening vibration and reducing shock according to one preferred embodiment of this invention; 
       FIG. 18  is a chart showing vibration and shock imparted to a standard archery bow; and 
       FIG. 19  is a chart showing vibration and shock imparted to a standard archery bow equipped with a device for dampening vibration and reducing shock according to one preferred embodiment of this invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1-12  show device  10  for reducing vibration and shock in an archery bow according to several preferred embodiments of this invention. As shown in  FIG. 16 , such devices  10  are preferably attached to bow limbs  19  on archery bow  17  to reduce vibration and shock imparted to archery bow  17  when an arrow is released. 
   Device  10  preferably includes base  20  and body  40  integrally formed of a flexible material. Appropriate materials include butyl rubber or other suitable elastomer having similar properties including a proper balance of elasticity, rigidity and durability. 
   Base  20 , such as shown in  FIG. 2 , is preferably generally flat across a bottom surface  30  and provides an adequate footprint to attach with respect to archery bow  17 . According to one preferred embodiment of this invention, base  20  is attached directly to archery bow  17  using adhesive, tape or other suitable manner of attaching an elastomer to a composite archery bow limb  19 . 
   Body  40  is integrally formed with base  20 , preferably during a molding process. However, base  20  and body  40  may be integrally molded, insert molded, overmolded with respect to each other or otherwise integrated to comprise a unitary device  10 . Body  40  includes a non-uniform cross-section as body  40  approaches a distal end, specifically, the cross-section of body  40  changes as body  40  extends away from base  20 , i.e. across a longitudinal length of body  40 . According to one preferred embodiment of this invention, the non-uniform cross-section tapers in a continuously decreasing cross-sectional area as body  40  extends away from base  20 . According to a preferred embodiment of this invention shown in  FIGS. 1-5 , body  40  and base  20  have footprints of generally the same dimensions. 
     FIGS. 1-5  show device  10  wherein body  40  comprises a tapered, inverted pyramid shape having a generally hollow center.  FIGS. 6-9  show device  10  wherein body  40  comprises a tapered “V” shaped profile. According to one preferred embodiment of this invention, each arm  45  of the “V” shaped profile includes a tapered cross-section that reduces in cross-sectional area as it approaches a distal end of body  40 . 
   Peripheral mass  60  is preferably positioned on a portion of body  40  opposite base  20 . Peripheral mass  60  preferably comprises perimeter weighting along body  40 . Perimeter weighting, when properly placed on or within device  10 , assists in reducing shock. Perimeter weights, or more accurately masses such as peripheral mass  60 , are preferably integrally molded with body  40  and base  20  or may comprise one or more separate components. Peripheral mass  60  preferably reacts with bow limb  19  following discharge of arrow. As a result of a combination of a non-uniform cross-section of body  40  and peripheral mass  60 , the shock imparted to archery bow  17  during arrow launch is greatly reduced. 
   As discussed above, body  40  preferably has a broader cross-section toward base  20  and a narrower cross-section toward peripheral mass  60 . Peripheral mass  60  may include a thickened or increased cross-sectional area for obtaining the necessary perimeter weighting. For example, peripheral mass  60  may include two or more flanges  65  extending laterally across body  40 . 
   According to a preferred embodiment of this invention shown in  FIGS. 1-5 , peripheral mass  60  may include one or more tabs  70  positioned in generally parallel alignment with a bottom surface  30  of base  20 . Tabs  70  are preferably positioned to vibrate out of phase with bow limb  19  and also out of phase with the remainder of body  40 . Preferably tabs  70  extend over a hollow area of body  40  to permit free motion of tab  70  relative to body  40 . 
   According to another preferred embodiment of this invention, one or more ribs  80  are positioned between peripheral mass  60  and base  20 . Ribs  80 , such as shown in hidden lines in  FIG. 9 , may be positioned to strengthen device  10  as a unit but still permit free vibration of body  40  and peripheral mass  60 . 
   As shown variously in  FIGS. 1-12 , device  10  may further comprise through hole  50  extending through a center of body  40 . Through hole  50  both encourages vibration of body  40  and also provides an attachment point for hardware to connect device  10  relative to archery bow  17 . 
   As shown in  FIGS. 13-15  and  17 , device  10  may be applied to archery bow  17  in a system  15  for reducing vibration and shock. According to this system, mount  90  is positioned on limb  19  of archery bow  17 . Mount  90  may be adhered or integrally formed with a conventional archery bow or anchored or otherwise positioned in the split of a split limb archery bow. 
   Device  10 , such as various embodiments described above, is then positioned on either side of mount  90  and connected to mount  90  so that device  10  on a top side of mount  90  is axially aligned with device  10  on a bottom side of mount  90 . The resulting system  15  therefore includes mount  90  and two devices  10 , one device  10  on a front of bow limb  19  and one device  10  on a back of bow limb  19 , each device  10  in axial alignment with the other. As shown in  FIGS. 13-15 , hardware may be used to connect devices  10  to mount  90  through through hole  50  positioned through each device  10 . 
     FIG. 18  shows vibration over time in a typical archery bow following release of an arrow.  FIG. 19  shows vibration over time in the same archery bow having system  15  mounted with respect to each bow limb. As evident, the initial vibration (measured displacement) which translates to shock is greatly reduced using system  15  according to this invention. In addition, vibration over time is greatly reduced when using system  15  according to this invention. 
   While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described can be varied considerably without departing from the basic principles of the invention.