Racquet having elongated grommet barrels with improved damping characteristics

Abstract

A sports racquet with enhanced string vibration damping has grommets with elongated barrels on many of the cross strings. The internal diameter of the barrels is selected so as to preserve a minimum clearance between the cross string and its enclosing barrel, thereby mitigating vibration. The barrel lengths vary as a function of their distance from the top of the frame, so that their free ends are positioned near the nearest main string.

I claim: 
     
         1 . A sports racquet comprising:
 a racquet frame having an axis, a head of the racquet frame laterally surrounding a string bed, the head having a lateral interior surface, the string bed residing in a string bed plane, a string bed boundary formed by the intersection of the interior surface of the head and the string bed plane;   a plurality of spaced-apart grommet holes formed through the frame and disposed around at least a portion of the head;   the string bed having a plurality of strings including main strings and cross strings, the cross strings strung at an angle to the axis, strung in spaced relation to each other, and strung to intersect the main strings, at least some of the cross strings received into respective grommet holes in the head, an outer length of the cross string defined to extend between the string bed boundary and an intersection of the cross string with the nearest main string;   each of the grommet holes being provided with a grommet, a plurality of elongated, vibration-dampening barrels formed as portions of ones of the grommets, each barrel enclosing a respective enclosed cross string, each barrel extending through a grommet hole and extending into the string bed, the barrel covering at least about 75% of said outer length.   
     
     
         2 . The racquet of  claim 1 , wherein the barrel covers between about 76% and about 90% of said outer length of said enclosed cross string. 
     
     
         3 . The racquet of  claim 1 , wherein each barrel has an inner wall with an inner radius and the cross strings have an outer surface with an outer radius, a difference between the inner radius and the outer radius preselected to be at least about 0.14 mm. 
     
     
         4 . The racquet of  claim 3 , wherein the difference between the inner radius and the outer radius is preselected to be at least about 0.16 mm. 
     
     
         5 . The racquet of  claim 4 , wherein the difference between the inner radius and the outer radius is preselected to be at least about 0.19 mm. 
     
     
         6 . The racquet of  claim 5 , wherein the difference between the inner radius and the outer radius is preselected to be in the range of 0.64 mm to 0.69 mm. 
     
     
         7 . The racquet of  claim 1 , wherein each of a majority of the cross strings strung on the racquet are strung through at least one of said barrels. 
     
     
         8 . The racquet of  claim 1 , wherein each of more than seven cross strings strung on the racquet is strung through at least one of said barrels. 
     
     
         9 . The racquet of  claim 1 , wherein the barrels are provided in pairs, one barrel of each pair extending into the string bed from the frame on one side of the string bed, a second barrel of the pair extending into the string bed from the frame on an opposite side of the string bed, a respective cross string being strung through each pair of barrels. 
     
     
         10 . The racquet of  claim 1 , wherein each barrel has an inner diameter and the cross strings each have an outer diameter, the inner diameter of the barrel being greater than the outer diameter of the cross string enclosed by the barrel by at least 21%. 
     
     
         11 . The racquet of  claim 10 , wherein the inner diameter of the barrel is greater than the outer diameter of the cross string enclosed by the barrel by at least 33%. 
     
     
         12 . The racquet of  claim 11 , wherein the inner diameter of the barrel is in the range of about 1.9 to about 2.2 times the cross string diameter. 
     
     
         13 . The racquet of  claim 1 , wherein a plurality of the barrels are integrally formed with a grommet strip disposed laterally exterior to the frame. 
     
     
         14 . The racquet of  claim 13 , wherein the racquet frame has a top, barrels formed on the grommet strip having lengths which generally increase as a function of the barrel's distance from the top of the racquet frame. 
     
     
         15 . The racquet of  claim 13 , wherein first and second grommet strips are disposed on opposite sides of the frame, a plurality of elongated barrels integrally formed with and extending from each grommet strip. 
     
     
         16 . The racquet of  claim 1 , wherein the racquet frame has a top, the plurality of barrels include a spaced-apart array of barrels enclosing respective cross strings, a length of the barrels in the array generally increasing as a function of the barrel's distance from the top of the frame. 
     
     
         17 . The racquet of  claim 1 , wherein each elongated barrel is made of a material consisting essentially of a polyether with an amide blocker. 
     
     
         18 . The racquet of  claim 1 , wherein each elongated barrel is made of a material consisting essentially of a polyamide. 
     
     
         19 . A sports racquet comprising:
 a racquet frame having an axis, a head laterally surrounding a string bed, the head having a lateral interior surface, the string bed residing in a string bed plane, a string bed boundary formed by the intersection of the lateral interior surface of the head and the string bed plane;   a plurality of spaced-apart grommet holes formed through the frame and disposed around at least a portion of the head;   the string bed having a plurality of strings including main strings and cross strings, the cross strings strung at an angle to the axis, strung in spaced relation to each other, and strung to intersect the main strings, at least some of the cross strings received into respective grommet holes in the head, an outer length of the cross string defined to extend between the string bed boundary and an intersection of the cross string with the main string nearest to the string bed boundary;   a plurality of grommets inserted into the grommet holes, a plurality of elongated, vibration-dampening barrels formed as portions of ones of the grommets, each barrel having a free end and enclosing a respective enclosed cross string, each barrel extending through a grommet hole and into the string bed so that the free end of the last said barrel is no more than about 15 mm from the main string nearest the string bed boundary.   
     
     
         20 . The racquet of  claim 19 , wherein the free ends of the barrels are each displaced from the nearest main string by a distance in the range of about 2 mm to about 13 mm. 
     
     
         21 . The racquet of  claim 19 , wherein the grommets with elongated barrels are disposed on at least eleven cross strings. 
     
     
         22 . The racquet of  claim 19 , wherein a plurality of the barrels are integrally formed with a grommet strip disposed laterally exterior to the frame. 
     
     
         23 . The racquet of  claim 19 , wherein first and second grommet strips are disposed on opposite sides of the frame, a respective plurality of elongated barrels integrally formed with each of the first and second grommet strips. 
     
     
         24 . The racquet of  claim 19 , wherein each elongated barrel is made of a material consisting essentially of a polyether with an amide blocker. 
     
     
         25 . The racquet of  claim 19 , wherein each elongated barrel is made of a material consisting essentially of a polyamide. 
     
     
         26 . The racquet of  claim 19 , wherein the cross string has a predetermined diameter, an interior diameter of each barrel being at least 21% greater than the enclosed cross string diameter. 
     
     
         27 . The racquet of  claim 26 , wherein the interior diameter of each barrel is at least 33% greater than the cross string diameter. 
     
     
         28 . The racquet of  claim 27 , wherein the interior diameter of each elongated barrel is in the range of about 1.9 to about 2.2 times the cross string diameter. 
     
     
         29 . The racquet of  claim 19 , wherein a clearance between an inner surface of each elongated barrel and an outer surface of the cross string enclosed by the last said elongated barrel is at least 0.14 mm. 
     
     
         30 . The racquet of  claim 29 , wherein the clearance between the inner surface of each elongated barrel and the outer surface of the cross string enclosed by the last said elongated barrel is at least 0.16 mm. 
     
     
         31 . The racquet of  claim 30 , wherein the clearance between the inner surface of each elongated barrel and the outer surface of the cross string enclosed by the last said elongated barrel is at least 0.19 mm. 
     
     
         32 . The racquet of  claim 31 , wherein the clearance between the inner surface of each elongated barrel and an outer surface of the cross string enclosed by the last said elongated barrel is in the range of about 0.64 mm to about 0.69 mm. 
     
     
         33 . The racquet of  claim 19 , wherein at least 22 grommets with elongated barrels are disposed on the cross strings. 
     
     
         34 . The racquet of  claim 19 , wherein for each cross string on which a grommet with an elongated barrel is disposed, a second grommet with an elongated barrel is disposed at an opposed intersection of the string bed boundary and the cross string. 
     
     
         35 . The racquet of  claim 19 , wherein each of the elongated barrels is integrally formed on one of a first and a second grommet strip segment. 
     
     
         36 . The racquet of  claim 19 , wherein each grommet with an elongated barrel is made of a material consisting essentially of polyether with an amide blocker. 
     
     
         37 . The racquet of  claim 19 , wherein each grommet with an elongated barrel is made of a material consisting essentially of a polyamide.