Patent Publication Number: US-6663516-B2

Title: Game racquet with separate head and handle portions for reducing vibration

Description:
RELATED U.S. APPLICATION DATA 
     The present application is a continuation of U.S. patent application Ser. No. 09/849,965, entitled “Game Racquet With Separate Head And Handle Portions For Reducing Vibration,” filed on May 4, 2001 by Severa et al now U.S. Pat. No. 6,500,080. 
    
    
     BACKGROUND 
     This invention relates to game racquets, and, more particularly, to a game racquet with separate head and handle portions which are separated by, and joined with, shock and/or absorbing material. 
     Game racquets such as tennis racquets, racquetball racquets, and squash racquets include a head portion and a handle portion. The head portion supports a string bed, and the player holds the racquet by the handle portion. 
     When the head portion strikes a ball, shock and vibration are transmitted from the head portion through the handle portion to the player&#39;s arm. Such shock and vibration can cause discomfort and can lead to physical problems such as tendinitis or tennis elbow. 
     Shock is caused by the impact of a ball on the strings. Shock on a typical tennis racquet might last about 3 milliseconds after ball impact. 
     Vibration is caused by shock and lasts longer. Vibration might last about 1000 milliseconds in a typical tennis racquet. 
     Many prior attempts have been made to reduce the transmission of shock and vibration to the player&#39;s arm. However, any direct connection between the head portion and the handle portion can provide an area through which shock and vibration can be transmitted. A conventional one-piece racquet acts as a conduit of vibration from the head to the handle. 
     U.S. Pat. No. 4,609,198 describes a racquet in which a tubular damping pad is positioned within the grip of the racquet. 
     SUMMARY OF THE INVENTION 
     The invention provides a game racquet with separate head and handle portions The handle portion includes arms which extend along portions of the head, and the head and handle portions are separated by, and joined with, shock and/or vibration absorbing material such as urethane or rubber which reduces the transmission of shock and vibration from the head portion to the handle portion. 
     The head and handle portions are advantageously joined to the shock and/or vibration absorbing material by adhesive or an adhesive agent. If desired, an additional mechanical connection between the head and handle portions can be provided, for example, by strings which extend through string holes in both the head and the handle portions. 
     The shock and/or vibration absorbing material is advantageously urethane, natural rubber, butyl rubber, or synthetic rubber and has a Shore A hardness within the range of 0 to 90, more preferably within the range of 20 to 70, and most preferably within the range of 30 to 60. Other relatively soft polymeric materials could also be used. 
    
    
     DESCRIPTION OF THE DRAWING 
     The invention will be explained in conjunction with the attached drawing, in which 
     FIG. 1 is a front view of one embodiment of a game racquet which is formed in accordance with the invention; 
     FIG. 2 is a side view of the racquet of FIG. 1; 
     FIG. 3 is a front view of another embodiment of a racquet which is formed in accordance with the invention; 
     FIG. 4 is a side view of the racquet of FIG. 3; 
     FIG. 5 is a front view of the head portion of the racquet of FIG. 3; 
     FIG. 6 is a side view of the head portion of FIG. 5; 
     FIG. 7 is a front view of the handle portion of the racquet of FIG. 3; 
     FIG. 8 is a side view of the handle portion of FIG. 7; 
     FIG. 9 is a plan view of the strip of shock and/or vibration absorbing material which separates the head and handle portions of FIGS. 5 and 7; 
     FIG. 10 is a side view of the strip of FIG. 9; 
     FIG. 11 is a top view of a cap of shock and/or vibration absorbing material which separates the head and handle portions of FIGS. 5 and 7; 
     FIG. 12 is a side view of the cap of FIG. 11; 
     FIG. 13 is a side view of the cap of FIG. 12; 
     FIG. 14 is a front view of another embodiment of a game racquet which is formed in accordance with the invention; 
     FIG. 15 is a side view of the racquet of FIG. 14; 
     FIG. 16 is a front view of the head portion of the racquet of FIG. 14; 
     FIG. 17 is a side view of the head portion of FIG. 16; 
     FIG. 18 is a front view of the handle portion of the racquet of FIG. 14; and 
     FIG. 19 is a side view of the head portion of FIG.  18 . 
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Referring to FIGS. 1 and 2, a tennis racquet  25  includes a head portion  26  and a handle portion  27 . The handle is aligned with a longitudinal centerline CL of the racquet. Although the invention will be explained with reference to a tennis racquet, it will be understood that the invention can be used with other game racquets such as racquetball racquets and squash racquets. 
     The head and handle portions can be formed from any conventional material for game racquets. For example, either or both of the head and handle portions could be made from thermoplastic or thermoset materials or a combination of thermoplastic and thermoset materials. The preferred material is a graphite and resin composite. The head and handle portions can be formed from the same or different materials. 
     The head portion includes a hoop  28  and a generally V-shaped throat portion  29 . The hoop includes a top portion  30 , side portions  31  and  32 , and a bottom or yoke portion  33 . The throat includes a pair of arms  34  and  35  which converge downwardly and inwardly from the sides of the hoop. 
     A string bed  36  is supported by the hoop  28  in the conventional manner. The string bed includes longitudinally extending main strings  37  and cross strings  38 . 
     The handle portion  27  includes a grip portion  40  which is wrapped with grip material and a throat portion which is formed from a pair of arms  41  and  42  which diverge outwardly and upwardly from the grip portion. Each arm includes an upper end  43  which is adjacent the juncture between the yoke  33  and the sides  31  and  32  of the hoop. 
     As will be explained in detail with respect to the embodiment illustrated in FIG. 3, material which absorbs shock and/or vibration is positioned between the head and handle portions and isolates the head and handle portions. Each of the head and handle portions is attached to the shock and/or vibration absorbing material, advantageously by adhesive or an adhesive agent, and the head and handle are thereby connected to each other. 
     FIGS. 3 and 4 illustrate another embodiment of a racquet  44  which is similar to the racquet  25 . The racquet  44  includes a head portion  45  and a handle portion  46  which extends along the centerline CL of the racquet A bumper strip  47  can protect the top of the head portion if desired. 
     Referring to FIGS. 5 and 6, the head portion includes a hoop  48  and a V-shaped throat portion  49 . The throat portion includes a pair of arms  50  and  51  which extend downwardly from shoulders or undercuts  52  and  53  in the hoop  48  toward the longitudinal centerline CL. The lower ends of the arms are joined by a connecting portion  54 , and a tapered projection  55  extends downwardly from the connector  54 . Shoulders  56  extend laterally between the projecting  55  and the front and rear faces of the head portion. 
     Referring to FIGS. 7 and 8, the handle portion  46  includes a grip portion  62  and a throat portion which is formed from a pair of diverging arms  63  and  64 . Each arm includes an inside surface  65  and an angled upper end  66  which mates with one of the shoulders  52  or  53 . A socket  67  extends into the top of the grip portion between the arms  63  and  64 . 
     FIGS. 9 and 10 illustrate a panel or sheet  68  of material for absorbing shock and/or vibration which is positioned between the outer surfaces  57  of the throat portion and the inside surfaces  65  of the handle portion. The particular panel illustrated includes a flat end portion  69  which is provided with cutouts or recesses  70  and a pair of elongated parallel strips  71  which are joined by a crosspiece  72 . The strips are separated by recesses  73  and  74 . The recesses  70 ,  73 , and  74  are intended primarily to reduce the weight of the panel  68 . However, the panel could be any shape and could be solid, i.e., without any openings or recesses. Alternatively, the shock and/or vibration absorbing material could be formed from a plurality of separate pieces. 
     The panel  68  can be formed from any material which provides shock absorbing and/or vibration dampening properties. Such materials include rubber, synthetic or butyl rubber, Kraton rubber, and urethane. One specific embodiment was made from soft chlorobutyl rubber which included filler and oils sufficient to provide a Shore A hardness of 33. 
     The panel  68  preferably has a Shore A hardness within the range of 0 to 90, more preferably within the range of 20 to 70, and most preferably within the range of 30 to 60. Shore A hardness is measured in accordance with ASTM D-2240-00. 
     FIGS. 11-13 illustrate a cup  80  of shock absorbing material which is positioned between the projection  55  of the head portion and the socket  67  of the handle portion. The cup includes a sidewall  81  which has the same dimensions as the socket  67  and a socket  82  which has the same dimensions as the projection  55 . Flanges  83  extend upwardly from two sides of the sidewall  81 , and flanges  84  extend laterally from the other sides of the sidewall  81 . 
     The cup  80  is attached to both the projection  55  and the socket  67 , preferably by adhesive or an adhesive agent which will not separate during normal use of the racquet. The preferred adhesive bonding agent is Loctite  496 , which is a Cyanoasrylate Ester adhesive. The flanges  83  extend upwardly between the arms  50  and  51  of the head portion and the arms  63  and  64  of the handle portion. The flanges  84  extend between the top of the socket  67  in the handle portion and the shoulders  56  of the head portion. Similarly, a panel  68  is attached to the outer surface  57  of each of the throat arms  50  and  51  and to the inside surface  65  of each of the handle arms  63  and  64 . The strips are also preferably bonded by an adhesive, for example, Loctite  496 . 
     The panels  68  and the cup  80  separate or isolate the head portion from the handle portion so that there is no direct contact between those parts. However, since each part is securely bonded to the panels  68  and the cup  80 , the parts are connected together by the panels and cup and will not separate during normal use of the racquet. The panels  68  and cup  80  significantly reduce the transmission of shock and vibration from the head portion to the handle portion. 
     If desired the projection  55  and socket  67  could be omitted. In that event the cap  80  can be replaced by a suitably shaped piece which prevents direct contact between the head and the handle. 
     A mechanical connection between the head portion and the handle portion can be provided by the racquet strings. Referring to FIG. 5, the head portion is provided with at least one string hole  85  which extends through the undercuts  52  and  53  of the throat arms  50  and  51 . A corresponding string hole  87  (FIG. 8) extends through the upper end of each of the handle arms  63  and  64 . The holes  85  and  87  are aligned when the head and handle portions are connected by the panels  66  and cup  80 . When the racquet is strung, one of the main strings  37  extends through the holes  85  and  89  on each side of the racquet and further secure the head and handle portions together. The strings extend through the middle recesses  70  in the panels  68 . Alternatively, the panels  68  could be shaped so that the strings do not pass through the panels. 
     The mechanical connection which is provided by the strings is located near the upper ends of the handle arms  63  and  64 . The lower ends of the handle arms are therefore free to move slightly relative to the lower ends of the throat arms  50  and  51  as the panels  68  and cup  80  are compressed by forces which are exerted on the racquet. Such relative movement assists in absorbing shock. 
     It is not necessary to have the racquet strings extend through the head and the handle. The head and handle could be connected solely by the adhesive bond to the vibration and/or shock absorbing material. 
     FIGS. 14-19 illustrate another embodiment of a racquet  90  which includes a head portion  91  and a handle portion  92  which extends along the centerline CL. The head portion  91  includes a hoop  93  which has a top portion  94 , side portions  95  and  96 , and a bottom or yoke portion  97 . A pair of short throat portions  98  and  99  extend downwardly from the yoke. 
     The side portion  95  includes a first outer edge  101  and a second recessed convex outer surface  102  which extends downwardly from about an undercut  103  at 4:00 o&#39;clock to the end of the throat portion  98 . Similarly, the side portion  96  includes a first outer edge  104  and a recessed convex outer surface  105  which extends downwardly from an undercut  106 . Referring to FIG. 17, the recessed portions of the sides  95  and  96  taper inwardly at  107  so that the top and bottom edges  108  are offset toward the midplane MP from the top and bottom edges  110  and  111  of the remainder of the head. 
     The handle portion  92  includes a grip portion  114  and a throat formed by a pair of diverging arms  115  and  116  which extend away from the centerline CL. The arm  115  includes a lower portion  117  which has a concave inside surface  119  which mates with the convex outer surface  102  of the head. The arm  116  similarly includes a lower portion  120  and an upper portion  121  which has a concave inside surface  12  which mates with the convex surface  105  of the head. 
     A panel  124  of shock and/or vibration absorbing material is inserted between each of the arms  115  and  116  and the head and secured by a chemical or an adhesive bond. Each panel  124  is preferably similar to the panel  68  and is secured by Loctite  496  to both the head and handle portions. The panels isolate the head and handle portions 
     A plurality of string holes  126  (FIG. 17) are provided in the recessed side portions  102  and  105 , and a plurality of string holes  127  (FIG. 19) are provided in the upper portions  118  and  120  of the arms of the handle portion. Strings which extend through the string holes  126  and  127  provide an additional mechanical attachment between the head and the handle. 
     If desired, the arms  115  and  116  of the handle portion can extend upwardly for a greater distance along the sides of the head portion. Also, the short throat portions  98  and  99  of the head can be omitted if desired. The head portion can be entirely hoop-shaped, and the arms of the handle portion can follow the contour of the hoop for any portion of the head which is desired. The handle portion can also extend along the centerline of the racquet up to the head portion so that the racquet does not have an open throat between the head and the handle. 
     While in the foregoing specification a detailed description of specific embodiments of the invention has been set forth for the purpose of illustration, it will be understood that many of the details hereingiven can be varied considerably by those skilled in the art without departing from the spirit and scope of the invention.