Abstract:
Vibration dampeners (DTM&#39;s) designed to surround a device in which unwanted vibrations (including shocks) are set up during use or a component of the device. The DTM significantly shortens the duration of those vibrations, reducing sound levels, making the device more comfortable to use in wielded instrument applications of the invention, and/or significantly reducing the possibility that the vibrations might damage the device. A representative, but significant, use of the subject DTM&#39;s is to dampen the vibrations generated when an arrow (or bolt) is shot from a crossbow.

Description:
CROSS REFERENCE TO A RELATED APPLICATION 
       [0001]    The benefit of the filing date of provisional patent application No. 61/460,569 is claimed. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    In one aspect the present invention relates to novel, improved vibration decay time modifiers (DTM&#39;S) which can be used to advantage in a host of applications to materially reduce the adverse effects of sound and vibration generated in a device or artifact. In a second aspect, the present invention relates to cross bows equipped with DTM&#39;s employing the principles of the present invention. 
       DEFINITIONS 
       [0003]    Mushroom Configuration: one which has: (a) a symmetric or asymmetric head or lobe with a continuous periphery of regular, indented, or other shape; and (b) a stem which is integral with and extends from the head or lobe. DTM device: one which shortens sound and vibration decay time and thereby reduces the deleterious effects of those phenomena such as user discomfort and equipment damage. In the DTM devices disclosed herein, decay time modification is accomplish by the lengthening, bending, and other distortions of an elastomeric material from which the DTM is made when vibrations are generated in the device or artifact to which the DTM is mounted. Vibration: a term at times used herein to include both vibrations which are in the audible range (i.e., sound) and those that are not. The term is also intended to encompass those vibrations commonly referred to as shocks. Wielded Instrument; a device or tool or implement which is handled by a user. The term includes such diverse things as, by way of example only, tool handles, cycles, golf clubs and other sports equipment, and archery bows. 
       BACKGROUND OF THE INVENTION 
       [0004]    U.S. Pat. Nos. 5,362,046 and 6,298,843, both issued to Sims, disclose state-of-the art decay time modifiers which have been successfully employed in a wide variety of applications. The DTM&#39;s disclosed in the &#39;046 and &#39;843 patents are limited in application to the extent that they are restricted to use with devices which have a flat surface to, or between which, the DTM or a DTM-supporting mount can be attached. 
       SUMMARY OF THE INVENTION 
       [0005]    Disclosed herein are new and novel DTM&#39;S which can be used in virtually any instance in which they can be slipped onto or trained around an element of a device which vibrates in a manner that one wishes to modify. DTM&#39;s of the present invention can optionally be secured in place with a fastener such as a zip tie, a compression elastic band or clamp, a head and slot system, a dovetail and pin arrangement, etc. 
         [0006]    DTM&#39;s constructed in accord with the principles of the present invention are fabricated from elastomeric materials. They may have a head and stem, a single lobe and stem, multiple lobes separated by one or more integral stems, or a head and one or more lobes, each with an associated stem. Each head or lobe and an associated stem element constitute what is identified in the &#39;046 patent as a mushroom configuration. 
         [0007]    When vibrations are set up in the device to which the DTM is mounted, the lobe(s) and/or mushroom head and the associated stem(s) undergo 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 herein disclosed DTM&#39;s, as a class, are identified herein by the judicially approved and construed term “wiggle and jiggle”. This wiggling and jiggling of the elastomeric material from which the DTM&#39;s are made materially reduces the time required for the vibrations to die out. This results in significant advantages, not the least of which are reduced sound and, in the case of a handheld device, a device which is more comfortable to use. 
         [0008]    The heads and lobes of the DTM&#39;s disclosed herein may be either symmetrically or asymmetrically related to the axial centerline of the DTM. Asymmetrical heads and lobes have the advantage that, in many applications, they can be kept from interfering with the operation of the device. 
         [0009]    Cross bow applications are exemplary of those in which the DTM&#39;s disclosed herein can be used to particular advantage. Specifically, cross bows are commonly equipped with foot stirrups to facilitate the cocking of the cross bow. The archer places the stirrup on a supporting surface, puts his foot on the stirrup to hold it, and proceeds to cock the bow. 
         [0010]    When an arrow (or bolt) is shot from the bow, the stirrup vibrates like a tuning fork, generating significant, and unwanted, sound and vibration. The effects of this sound and vibration is materially reduced by installing vibration DTM&#39;s embodying the principles of the present invention on the foot stirrup. 
         [0011]    The DTM&#39;s of the present invention can of course be used to modify sound and vibration in a host of other devices and artifacts including, but not limited to: handle bars; luggage racks; the shafts of golf clubs and components of other wielded instruments; lawn mowers and edgers; industrial machinery; and bars, pipes, and rods. In actuality, the list is almost endless. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIGS. 1-6  are, respectively, perspective, front, top, left-hand, right-hand, and rear views of an elastomeric, asymmetric lobe DTM fabricated in accord with, and embodying, the principles of the present invention 
           [0013]      FIGS. 7-13  are two perspective views and front, top, left-hand, right-hand, and rear views of a second, asymmetric lobe DTM embodying the present invention; 
           [0014]      FIGS. 14-22  are four perspective views, a top view, a front view, left-hand and right-hand views, and a bottom view which illustrate a third, in this case symmetric head, embodiment of the invention; 
           [0015]      FIG. 23  illustrates the steps employed in attaching a  FIGS. 14-22  DTM to a component. 
           [0016]      FIGS. 24-29  are, respectively, a perspective view, a front view, a top view, and left-hand and right-hand views of a fourth embodiment of the invention which features multiple, symmetric lobes; 
           [0017]      FIG. 30  is a perspective view of a cross bow equipped with DTM&#39;s embodying the principles of the present invention to dampen vibrations set up in the crossbow stirrup when an arrow is shot from the crossbow; 
           [0018]      FIG. 31  is a fragment of  FIG. 30  drawn to an enlarged scale; and 
           [0019]      FIGS. 32-37  are, respectively, a perspective view, a front view, a top view, left- and right-hand views, and a rear view of two asymmetric lobe DTM&#39;s with which the  FIG. 30  crossbow cross bow is equipped; both DTM&#39;s are of the same construction and configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]      FIGS. 1-6  depict a first embodiment of the invention, which is a DTM  40 . The DTM  40  has two asymmetric lobes (mushroom heads)  42  and  44  with continuous peripheries that are in part generally straight and in part of an arcuate configuration; integral stems,  46 ,  48 , and  50 ; and an empty, unobstructed bore  52  extending end-to-end through an integral, axially oriented, stem and lobe—including DTM hub  53 , the lobes and stems being centrally apertured to form the bore  52 . 
         [0021]    The straight segments of the lobe peripheries are identified by reference characters  42 - 1  and  44 - 1 , and the arcuate segments of the peripheries are identified by reference characters  42 - 2  and  44 - 2 . 
         [0022]    The hollow DTM hub  53  is split (see reference character  54 ) so that it can be spread apart and DTM  40  installed on a device or artifact (not shown). Once the DTM has been installed, it is secured in place as by installing clamps, elastic bands, zip ties, etc. (not shown) on stems  46  and  50 . Flanges  56  and  58  on the outer ends of stems  46  and  50  keep the DTM-securing components from slipping off the stems. 
         [0023]    In the lobes and stems  42  . . .  50  of DTM  40 , vibrations are dampened by the wiggling and jiggling of the elastomeric material from which DTM  40  is made. 
         [0024]    DTM&#39;s like the one identified by reference character  40  have the significant advantage that they can by rotated about their axial centerlines (see the axial centerline  60  of DTM  40  in  FIG. 2 , for example). As pointed out above, this capability, and the asymmetric configuration of lobes  42  and  44 , make it possible to rotate the protruding, arcuate segments  42 - 2  and  44 - 2  out of the way and thereby keep the lobes  42  and  44  from interfering with the operation of the device to which DTM  40  is mounted. 
         [0025]    A second, two-lobe DTM embodying the principles of the present invention is shown in  FIGS. 7-13  and identified by reference character  70 . 
         [0026]    DTM  70  differs from DTM  40  in one respect in that a dovetail  72  and a pin  74  are employed to retain the DTM in place on the device or artifact (not shown) to which it is mounted; 
         [0027]    Dovetail  72  has a mortise  76  and a tenon  78  at opposite sides of DTM  70 . DTM hub  79 , which is split from end-to-end, is spread apart, allowing DTM  70  to be slipped onto a device or artifact. The pressure forcing hub edges  79 - 1  and  79 - 2  apart is then released, and tenon  78  slides into mortise  76  as best shown in  FIG. 9 . Pin  74  is then inserted through the mortise  76  and tenon  78  to fasten the edges  79 - 1  and  79 - 2  of DTM hub  79  together and secure DTM  70  to the device or artifact with which is is associated. 
         [0028]    DTM  70  also differs from DTM  40  in that its lobes  80  and  82  have integral, continuous, peripheral segments  80 - 1  and  82 - 1  that are in part generally arcuate but have centrally located indentations or scallops  84  and  86 . 
         [0029]    The DTM  70  is a highly efficient shock and vibration dampener. This is attributable in part to the above-discussed, scalloped configuration of arcuate lobe segments  80 - 1  and  82 - 1 . This scalloped lobe configuration produce lobes having a relatively stiff inner region  84 - 1  or ( 86 - 1 ) which efficiently dampens vibrations (including shock and sound) that have a high frequency and more flexible, integral outer regions ( 84 - 2  and  84 - 3  or  86 - 2  and  86 - 3 ) which efficiently dampen vibrations with lower frequencies. 
         [0030]    In lobes  80  and  82 , and in the integral stems  88 - 1  and  88 - 2  between those lobes, the scalloped configurations of lobes  80  and  82  described above promote, to an important extent, vibration dampening wiggling and jiggling of the elastomeric material because they have multiple operating modes. Specifically, the inner and outer regions  84 - 1 - 84 - 3  of lobe  80  and  86 - 1 - 86 - 3  of lobe  182  have different sizes and shapes and, consequentially, effectively dampen 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 most efficiently dampened. 
         [0031]      FIGS. 14-22  depict a DTM which is a third embodiment of the invention and which is identified by reference character  90 . DTM  90  has a generally frustoconical mushroom head  92  with a regular periphery, an integral stem  94 , and an also integral strap  96  which terminates at an integral loop  98 . 
         [0032]    Equiangularly spaced apart scallops  92 - 1  and  92 - 2  are formed on opposite sides of head  92  in the continuous periphery  100  of the head. Scallops  92 - 1  and  92 - 2  are symmetrically located with respect to the axial centerline  99  of DTM  90 . As discussed above in conjunction with DTM  70 , the scalloped configuration of the continuous periphery  100  promotes the wiggle and jiggle, vibration effecting capabilities of DTM  90 , 
         [0033]    As suggested above, one important use of the present invention is to minimize the vibrations set up in a crossbow stirrup when an arrow (or bolt) is shot from the crossbow. This can be easily and effectively accomplished by mounting a DTM such as the DTM  90  described above to a leg of the crossbow stirrup or, preferably, by mounting such DTM&#39;s to both stirrup legs. 
         [0034]    The steps involved in doing this are shown in  FIG. 23 . In that figure, a DTM  90  as disclosed above is shown in the process of being mounted to the leg  101  of a cross bow foot stirrup  102 . Specifically, DTM strap  96  is trained around foot stirrup leg  101 . Then mushroom head  92  of the DTM is then displaced through loop  98  until the bottom  104  of the mushroom head (see  FIG. 15 ) engages the loop to complete the installation process. The strap  96  is in a stretched condition at this point, and friction therefore keeps DTM  90  from sliding along foot stirrup leg  101 . 
         [0035]      FIGS. 24-29  depict a fourth embodiment of the invention, a DTM which is identified by reference character  120 . 
         [0036]    DTM  120  has two lobes  122  and  124  and a hollow, axially extending, DTM-mounting hub  125 . Lobes  122  and  124  have circular peripheries  122 - 1  and  124 - 1  centered on the longitudinal centerline  126  of the DTM (see the solid and dotted peripheral lines in  FIG. 26 ). 
         [0037]    DTM  120  is designed to be slid onto the device or artifact to which it is to be mounted. 
         [0038]    The circular periphery  122 - 1  or  124 - 1  of each lobe  122  or  124  is interrupted by shallow arcuate scallops  130  and  132  and by U-shaped indentations  134  and  136  that divide each lobe into segments which can move (i.e., wiggle and jiggle) independently and thereby increase the effectiveness of DTM  120  as discussed above in conjunction with DTM  70 . Scallops  130  and  132  are spaced 180 degrees apart around the periphery  122 - 1  or  124 - 1  of the lobe in which they are formed. Indentations  134  and  136  are also located 180 degrees apart in periphery  122 - 1  or  124 - 1 , and they are located between and at equal angular distances from scallops  130  and  132 . 
         [0039]    The DTM  120  also has flanged stems  138  and  140  and a stem  142  between lobes  122  and  124 . These stems, together with lobes  122  and  124 , make up hub  125 . 
         [0040]    DTM  120  may be retained in place by friction between it and the device of device component to which it is mounted. Optionally, retainers such as zip ties, cable clamps, elastic bands, etc. (not shown) may be installed on flanged stems  138  and  140  after the DTM has been mounted to the device or artifact. The retainers more securely hold the DTM  120  in place on the device or component to which it is mounted than friction alone does. The flanges  144  and  146  on, and at the exposed ends of, stems  138  and  140  keep the retainers from sliding off the stems. 
         [0041]      FIGS. 30 and 31  illustrate a crossbow equipped with DTM&#39;s embodying the principles of the present invention to dampen vibrations set up in the crossbow stirrup when an arrow is shot from the crossbow. 
         [0042]    The crossbow, identified by reference character  160 , has the customary stock  162 ; trigger mechanism  164 ; riser  166 ; flexible, riser-mounted limbs  168  and  170 ; and limb-supported, rotatable cams  172  and  174  of a binary cam system. Riser-mounted foot stirrup  176  facilitates the cocking of the bow, the archer placing his foot in the stirrup to hold the bow fast during the cocking process. DTM&#39;s  178  and  180  are installed on the legs  182  and  184  of foot stirrup  176  to modify the decay time of vibrations set up in the stirrup when an arrow (or bolt) is shot from cross bow  160 , This reduces the level of sound and the level of vibrations including those in the audible range that may make the bow less than comfortable to shoot. The DTM&#39;s  178  and  180  have scalloped lobes  178 - 1 / 178 - 2  and  180 - 1 / 180 / 2 . These lobes are purposely located outside the foot stirrup legs to which they are mounted. This keeps the DTM&#39;s from interfering when the bowman puts his foot in the stirrup (see especially,  FIG. 31 ). 
         [0043]    The scalloped lobes of DTM  178  identified by reference characters  178 - 1  and  178 - 2  are best shown in  FIGS. 30 and 31 , and the similarly scalloped lobes of DTM  180  identified by reference characters  180 - 1  and  180 - 2  are best shown in  FIG. 30 . Reference characters  178 - 3  and  178 - 4  identify scallops in the peripheries of arcuate lobe  178  segments  178 - 5  and  178 - 6 . The scallops in lobes  180 - 1  and  180 - 2  of DTM  180  are similarly located and configured. 
         [0044]    Shown in  FIG. 31  are foot stirrup leg  182 , the DTM  178  mounted on that leg, and one of two zip ties used to secure the DTM in place. The zip tie is identified by reference character  186 , and it is secured around stem  187  of DTM  178 . A second zip tie (not shown) is secured around DTM stem  188 . Integral flanges  190  and  192  at the outer ends of stems  187  and  188  keep the zip tie from sliding off the stems. 
         [0045]    DTM  180  is assembled in the same manner to the leg  184  of foot stirrup  176  that DTM  178  is mounted to foot stirrup leg  182 . 
         [0046]    Referring now to  FIGS. 30-37 , in addition to lobes  178 - 1  and  178 - 2  and the outer or end stems  187  and  188  with integral flanges  190  and  192 , DTM  178  has integral, inner stems  194  and  196  between lobes  178 - 1  and  178 - 2 . Lobes  178 - 1  and  178 - 2  and stems  187 ,  188 ,  194 , and  196  are centrally apertured and combine to form an axially extending hub  198  with a central bore  200  which extends from end-to-end through the hub, The hub  198  is concentric with the axial centerline  202  of the hub (see  FIGS. 33 and 34 ). 
         [0047]    Hub  198  is split from end-to-end as indicated by reference character  204  in  FIG. 31 . This allows DTM  178  to be spread apart to install it on foot stirrup leg  182 . Then, the forces keeping the DTM  178  spread apart are removed. This allows DTM  178  to relax to the configuration shown in  FIG. 31  and grip foot stirrup leg  182 . Finally, the zip tie  186  is installed around stem  187 , and a second zip tie (not shown) is installed on stem  188  to complete the process of securing DTM  178  to foot stirrup leg  182 . 
         [0048]    There are a number of elastomeric materials from which the DTM&#39;s of the present invention may be fabricated. Appropriate materials are those in the Sims Vibration Laboratory, Inc. NAVCOM® family of elastomers. 
         [0049]    The principles of the present invention may be embodied in forms other than those specifically disclosed above and in the drawings. As a single example, DTM&#39;s employing the principles of the present invention may have more than two lobes. Therefore, the embodiments presented herein are 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 the drawings; and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.