EP2994207A1 - Raquette ayant des tubes d' illet allonges ayant des caractéristiques d'amortissement améliorées - Google Patents

Raquette ayant des tubes d' illet allonges ayant des caractéristiques d'amortissement améliorées

Info

Publication number
EP2994207A1
EP2994207A1 EP14795419.2A EP14795419A EP2994207A1 EP 2994207 A1 EP2994207 A1 EP 2994207A1 EP 14795419 A EP14795419 A EP 14795419A EP 2994207 A1 EP2994207 A1 EP 2994207A1
Authority
EP
European Patent Office
Prior art keywords
racquet
string
barrel
cross
barrels
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP14795419.2A
Other languages
German (de)
English (en)
Other versions
EP2994207A4 (fr
Inventor
Ronald A. GRIMES
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EF Composite Technologies LP
Original Assignee
EF Composite Technologies LP
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EF Composite Technologies LP filed Critical EF Composite Technologies LP
Publication of EP2994207A1 publication Critical patent/EP2994207A1/fr
Publication of EP2994207A4 publication Critical patent/EP2994207A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B49/00—Stringed rackets, e.g. for tennis
    • A63B49/02—Frames
    • A63B49/022—String guides on frames, e.g. grommets
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B60/00—Details or accessories of golf clubs, bats, rackets or the like
    • A63B60/42—Devices for measuring, verifying, correcting or customising the inherent characteristics of golf clubs, bats, rackets or the like, e.g. measuring the maximum torque a batting shaft can withstand
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B60/00—Details or accessories of golf clubs, bats, rackets or the like
    • A63B60/54—Details or accessories of golf clubs, bats, rackets or the like with means for damping vibrations
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B2220/00—Measuring of physical parameters relating to sporting activity
    • A63B2220/64—Frequency, e.g. of vibration oscillation
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B2220/00—Measuring of physical parameters relating to sporting activity
    • A63B2220/80—Special sensors, transducers or devices therefor
    • A63B2220/808—Microphones

Definitions

  • Today's sports racquets such as tennis, racquetball, squash and badminton racquets, each have a frame with a head portion supporting a string bed, coupled to a shaft or handle.
  • the size and length of the head varies, depending on the particular sport for which the racquet is being used.
  • a projectile such as a ball or shuttlecock
  • the strings deflect and propel the projectile from the racquet, but the strings vibrate after the initial impact.
  • the resulting string vibration is transmitted to the frame of the racquet and eventually the handle or shaft, and, finally, to the hand, arm and shoulder of the user. This string vibration may cause user discomfort, or an incorrect feel for ball response.
  • Vibration damping devices have been incorporated into racquets in an effort to absorb and reduce these vibrations, which may lead to reduced performance because of incorrect feel, discomfort or fatigue. While there are many different types of damping devices, most attempt to absorb the vibration in the string bed before it is transmitted to the frame. Many such devices attach to the strings themselves in or near the throat of the racquet and are made of a rubber or silicone material that is conducive to absorbing vibration. Because these devices must be lightweight in order to minimally affect the balance and feel of the racquet, and because many of them are located to be remote from the main racquet hitting area, they may not provide sufficient damping to significantly reduce the vibration. Further, many are difficult to install and some are prone to fall off during play.
  • grommets are usually incorporated into racquets to prevent premature string wear.
  • a light-weight damping device into a racquet, near the hitting area, in the form of an elongated grommet, made from an elastic material that minimally affects the weight, balance and feel of the racquet, yet significantly reduces unwanted vibration in the string bed.
  • Such vibration as is felt should be better correlated to how well the ball has been struck, and should be more uniform between on-center and off-center hits.
  • the invention accordingly provides a sports racquet in which many of the cross strings are equipped with grommets having vibration-dampening extended barrels.
  • the preferably plastic barrels extend into the string bed from the boundary which the string bed makes with the racquet frame, so that at least about 75% of the cross string, from the cross string boundary to the first main string, is covered.
  • a free end of the barrel is disposed so as to no more than about 15 mm from the nearest main string.
  • the string gauge and interior diameter of the barrel are chosen such that there is at least 0.14 mm, preferably at least 0.16 mm, and more preferably at least 0.19 mm of clearance between the interior surface of the barrel and the exterior surface of the string.
  • an interior diameter of the barrel should be at least 21% greater than an exterior diameter of the string, and more preferably should be at least 33% greater than an exterior diameter of the string. It has been discovered that if at least this amount of clearance is maintained, the result is a dampened racquet with good stability and without an unwanted "buzz" or undamped vibration.
  • the barrels may be integrally formed with one or more grommet strips which are placed in proximity to the grommet holes of the frame, preferably on the lateral exterior of the frame.
  • the lengths of the barrels on any one grommet strip generally, but not always, increase as one proceeds from the top of the frame head to the throat.
  • Figure 1 is an isometric view of a sports racquet showing a head, a handle, a string bed, and grommets according to the prior art
  • Figure 2 is a plan view of a sports racquet according to a first embodiment of the invention.
  • Figure 3 is a plan view of a second embodiment of the invention, in which most of the cross strings are jacketed or enclosed by long-barrel grommets having free ends that are within a predetermined distance of the nearest main string;
  • Figure 4 is a side view of the prior art grommet strip having grommets with short barrels
  • Figure 5 is a side view of a grommet strip having grommets with elongated barrels
  • FIG. 6 is a side view of a grommet strip having grommets with elongated barrels and varied lengths, ends of the barrels disposed at a more constant distance from the nearest main string once the grommet strip is installed;
  • Figure 7 is a detail of an individual grommet with an elongated barrel
  • Figure 8 is a sectional detail taken substantially along line 8 - 8 of Figure 3;
  • Figure 9 is a cross section taken substantially along line 9 - 9 of Figure 8;
  • Figure 10 is an isometric view of a test fixture used to test the vibration damping effects of the invention;
  • Figure 11 is a top view of the test fixture
  • Figure 12 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 2, strung with 16 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 13 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, the barrels having an internal diameter of 1.5 - 1.6 mm and being strung with 16 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 14 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 2.6 mm and as strung with 16 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 15 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 2, strung with 17 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 16 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, the barrels having an internal diameter of 1.5 - 1.6 mm and being strung with 17 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 17 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 2.6 mm and as strung with 17 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 18 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 2, strung with 18 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 19 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, the barrels having an internal diameter of 1.5 - 1.6 mm and being strung with 18 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on a center of the string bed;
  • Figure 20 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 2.6 mm and being strung with 18 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the center of the string bed;
  • Figure 21 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 2, strung with 16 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 22 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, the barrels having an internal diameter of 1.5 - 1.6 mm and being strung with 16 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 23 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 2.6 mm and as strung with 16 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 24 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 2, and being strung with 17 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 25 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 1.5 - 1.6 mm and being strung with 17 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 26 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 2.6 mm and as strung with 17 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 27 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 2, strung with 18 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location;
  • Figure 28 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, the barrels having an internal diameter of 1.5 - 1.6 mm and being strung with 18 gauge string, as measured using the test fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location; and
  • Figure 29 is a graph showing vibration intensity versus time for a racquet substantially as shown in Figure 3, with barrels having an internal diameter of 2.6 mm and being strung with 18 gauge string, as measured using the text fixture of Figures 10 and 11 after a ball is dropped on the string bed at a predetermined off-center location.
  • a sports racquet indicated generally at 100, has a frame 102 with a handle 103, a head 104, a string bed 105, and a plurality of grommet holes 106 disposed around at least a portion of the head 104.
  • the frame 102 is defined to exclude any throat piece (not shown) or other structure at the throat area of the racquet where the head 104 and the handle 103 or shaft join.
  • the string bed 105 substantially resides in a string bed plane P.
  • the string bed has a number of cross strings 107 that laterally traverse the head 104 of the racquet 100 and a number of main strings 108 that longitudinally traverse the head 104.
  • the cross strings 107 intersect the main strings 108 at a considerable angle, and typically intersect the racquet longitudinal axis X (Figs. 2 and 3) at ninety degrees. Even though the cross strings 107 and main strings 108 are referred to in the discussion below as individual strings, it is contemplated that each of the cross strings 107 and main strings 108 be segments of a longer string or strings which are used to string the racquet 100. No limitation regarding the string bed, the strings themselves, the number, diameter, or length of the strings, the connectivity of the strings, the string physical or chemical composition, or any other string quality should be inferred by the discussion of the strings individually. Thus, each cross string 107 and main string 108 may have the same diameter as the other strings or may have its own separate string diameter. Cross strings 107 typically are parallel and spaced apart from each other.
  • the cross strings 107 extend between and enter respective grommet holes 106.
  • the frame head 104 has a laterally inward facing surface 112.
  • a string bed boundary 111 is defined as the intersection of the plane P with surface 112.
  • Grommet holes 106 each adjoin the string bed boundary 111.
  • One or more grommet strips 109 may be adjacent to the grommet holes 106 and are usually assembled to the lateral exterior of the frame 102.
  • sports racquet 100 may be a racquetball racquet of the "long string" type in which most or all of the main strings 108 are fed into a hollow handle 103 and are anchored at an anchor (not shown) at or near a handle end 110, or may be of a more conventional type in which some or all of the main strings 108 have lower anchoring points on the frame 102 or throat piece (not shown).
  • the invention may also be employed on other racquets such as those used for tennis, badminton or squash. If one end of a main string 108 is fed into a hollow handle, the opposing end will extend into a grommet hole 106 on top of the racquet.
  • each of the grommet holes 106 is fitted with a grommet that does not appreciably extend into the string bed, as its primary purpose is to serve as a bushing for the string as the string is routed through the frame 102.
  • FIG. 2 a sports racquet of the type of Figure 1 is shown, but with some of the grommets including or constituting barrels 202 being disposed on seven cross strings 107.
  • Barrels 202 are of a moderate and mostly uniform length.
  • This racquet has barrels 202 which extend about 29 mm from their junctions with the grommet strips 109 to their free ends 204, and extend into the string bed 105 by a substantially uniform 26 to 27 mm.
  • the free ends 204 are disposed at greatly varying distances from the nearest or most lateral main strings 210 (that is, the main strings closest to the string bed boundary 111), ranging from zero to more than 18 mm away from these closest main strings 210.
  • the cross strings 107 jacketed by barrels 202 may make up a portion of the "sweet spot," the center of which is illustrated by point or center 206, for the racquet or the specific location on the racquet string bed 105 where optimal contact with the projectile is desired.
  • the sweet spot is a general area on the string bed 105 where the coefficient of restitution is closest to one or at a maximum.
  • the sweet spot may vary according to user, string tension, materials, string type, frame construction, and style of play.
  • the sweet spot center 206 was controlled to be in the same place in terms of its distance from the frame top 212 and always to be on the racquet longitudinal axis X.
  • an intentionally off-center target 208 that has been displaced toward the handle 103 and is off-axis. The location of target 208 was controlled to stay the same, from one racquet to the next, for the off- center ball drop tests illustrated by Figures 21 - 29.
  • FIG. 3 shows a sports racquet 298 in which the long barrel grommets 300— 320 are of substantially different lengths, with their free ends 324 tending to be disposed at a closer and more even distance from a nearest main string 210.
  • the barrels range in length from about 24 to 26 mm at the top jacketed string (barrel 300) to about 39 to 42 mm at the bottom jacketed string (barrel 320). These barrel lengths are measured from the string bed boundary 111, or the point at which the string departs from the interior sidewall 112 of the frame 102, to the free end 324 of the barrel.
  • the distance between the free end 324 of the barrel and the nearest main string 210 also has a tendency to increase (with some exceptions) as the handle 103 is approached.
  • This distance is as short as about 2 mm at barrel 300 and may be as long as 15 mm at barrel 318. In an embodiment, the range of distances can be 2mm to 13mm.
  • More than seven cross strings 107 can be jacketed, and it is preferred that most of the cross strings 107 be jacketed or equipped with long barrels. In the embodiment illustrated in Figure 3, eleven cross strings 107, or the fifth through fifteenth cross strings 107, have end segments which are mostly enclosed or jacketed by barrels 300 - 320.
  • the amount of cross string 107 from the interior racquet frame sidewall 112 to the nearest main string 210 (as sometimes used herein, the string's "outer length") that is jacketed by a barrel also varies by percentage as one proceeds from barrel 300 to barrel 320.
  • Barrel 300 covers as much as 90% of the outer length of string 107; barrel 318 covers as little as 75% of the outer length of its respective cross string 107. More preferably this coverage is in the range of about 76% to 90%.
  • the percentage of coverage has a tendency to drop as one approaches the handle 103.
  • prior art grommets 401 attached to the prior art grommet strip 109 are prior art grommets 401 which have not been elongated into a vibration damping barrel.
  • the prior art grommets 401 are typically of a length that extends about 3 mm into the string bed from the string bed boundary.
  • the length of prior art grommets 401 is conventionally chosen to be enough to extend through frame 102 at a respective grommet hole 106. While grommets 401 are shown to be of uniform length, their length can be variable if the racquet head cross section thickness varies from place to place.
  • a grommet strip 500 has attached to it vibration damping grommets 501 with moderately elongated barrels 503.
  • the primary purpose for the elongated grommet barrels 503 is to dampen the vibration of the string bed 105 when the string bed 105 impacts a projectile. When the string bed 105 receives vibratory forces from the strike of a projectile, those forces are transferred to head 104 of the racquet 100 and eventually to the user.
  • Grommets 501 may also act to produce a more stable playing surface. Also present on the illustrated embodiment of grommet strip 500 are grommets 502 that do not have elongated barrels.
  • a grommet strip 500 may contain a combination of short grommets 502 and grommets 501 with elongated barrels 503.
  • Each grommet 501 with an elongated barrel 503 extends into the string bed 105 from the string bed boundary 111 by about at least 0.55 inches.
  • the grommets 501 extend into the string bed 105 from the string bed boundary 111 by about 26.7 to about 28.2 mm, and are each a little more than about 29 mm long as measured from their grommet strip backing.
  • a set of three improved grommet strip segments is seen in Figure 6.
  • a grommet strip segment 600A has, integrally molded with it, barrels 300 - 320.
  • Grommet strip 600A will be assembled to the left side of the racquet 298 and receives eleven cross strings 107.
  • barrels 300 - 320 have lengths which generally increase as a function of the distance from frame top 326 and as a function of their increasing proximity to the handle 103.
  • barrels 300 - 320 have respective lengths approximating 27.6 mm, 30.4 mm, 33.0 mm, 35.6 mm, 37.7 mm, 39.3 mm, 42.8 mm, 42.9 mm, 42.5 mm, 42.9 mm and 43.0 mm as measured from the grommet strip to the free end.
  • Barrels 312 - 320 are nearly of the same length while the length of barrels 300 - 310 increases more dramatically as a function of their distance from the top 326 of the frame. As inserted into grommet holes 106, a varying amount of these barrel lengths will be taken up in proceeding through the frame 102. Hence, a length of the barrels 300 - 320 as measured from the string bed boundary 111 to their free ends 324 will exhibit more variance as installed.
  • Strip segment 600A terminates, at an end proximate to barrel 300, with a grommet 602 without an extended barrel. This end grommet 602 receives a peg or sleeve 604 of a head grommet strip segment 606.
  • the head grommet trip segment 606 has no elongated barrels on it in the illustrated embodiment.
  • Grommet strip segment 606 is assembled to the frame 102 around the top of the head 104.
  • a grommet strip 600B identical to the previously described grommet strip segment 600A, is provided for the right side of the racquet frame 102.
  • a unitary grommet strip may be provided, or more grommet strip segments could be provided, as is convenient for molding or assembly.
  • a single grommet 700 with an elongated barrel 702 may be provided separately from a multiple-grommet grommet strip segment 600 A, 600B.
  • the single grommet 700 and any of the barrels 300 - 320 on grommet strips 600A, 600B has a barrel interior diameter 704 and a preferably a slightly tapered exterior diameter for ease in injection-molding the barrel-equipped grommets 700, 300 - 320.
  • An individual grommet 700 may be extended through a respective grommet hole 106 ( Figure 2).
  • Rhommets 298 according to the invention may be provided with one or more grommet strip segments, such as grommet strip segments 600A, 600B, a plurality of single long-barreled grommets 700, or both. It is contemplated that the grommets or barrels 700, 300-320 be placed on many, and preferably most, of the cross strings 107 of racquet 298 ( Figure 3).
  • the illustrated and tested frame 102 is a dual barrel frame, but no limitation as to the type of frame should be inferred.
  • the frame 102 has a grommet hole 106 through which a grommet with an elongated barrel 800 is inserted.
  • the long barreled grommet closely encloses a cross string 107.
  • a grommet barrel will be considered to closely enclose a string 107 if it has a vibration-damping effect thereon.
  • the string 107 has an outer diameter 900.
  • Common string sizes used in sports racquets include 18 gauge, with an outer diameter of 1.22 mm +/- 0.02 mm; 17 gauge, with an outer diameter of 1.27 mm +/- 0.02 mm; and 16 gauge, with an outer diameter of 1.32 mm +/- 0.02 mm.
  • the grommet barrel 800 as found on the "Invasion" and for which test results are illustrated by Figs. 13, 16, 19, 22, 25 and 28, may have an interior diameter 704 that is in the range of about 1.5 - 1.6 mm for racquetball, tennis and squash applications. This interior diameter is therefore from 1.2 times to about 1.33 times the string diameter 900.
  • the grommet 800 may be attached to a grommet strip 600A, 600B ( Figure 6) or may be an individual grommet 700 ( Figure 7). It is preferred that the inner diameter of the barrel be at least 21% greater than the string diameter. In another embodiment, the inner diameter of the barrel can be 33% greater than the string diameter. [0047] In the tested "Invasion X" embodiment, the barrel interior diameter is about 2.6 mm. As enclosing 18 ga. - 16 ga. strings, this means that the interior diameter of the barrel 800 is about 1.9 to 2.2 times the outer diameter of the cross string it is enclosing.
  • the clearance 902 is in the range of about 0.64 to 0.69 mm.
  • the clearance 902 should be at least 0.14 mm, preferably should be at least 0.16 mm, and more preferably should be at least 0.19 mm.
  • the inventors have determined that a non-brittle polymer which will flex and not break upon the impact of a projectile into the string bed should be used.
  • the polymer should be more flexible than the frame, yet should still be plastic enough to exhibit damping properties.
  • the polymer should have a flexural modulus in the range of 280-1730 MPa as measured under ISO 178 test methods. More preferably the flexural modulus is 390 MPa as measured under ISO 178 test methods.
  • the polymer should have a Charpy Notched Impact Strength of between about 5 and 125 kJ/m 2 under ISO 179 test methods.
  • the polymer should have a Charpy Notched Impact Strength of 120 kJ/m 2 at 23 degrees Celsius and 20 kJ/m 2 at -30 degrees Celsius. Preferably the polymer should not break in Charpy Unnotched Impact Strength tests under ISO 178 test methods.
  • a preferred polymer can be a polyether with an amide blocker, such as the amide formulation sold under the mark PEBAX 7033 SP 1. Another polymer that may be considered is a polyamide, such as the formulations commercially available as nylon 11 or nylon 12.
  • the tested strings were E-Force OxygenTM 16 - 18 gauge strings each strung to a finish tension of 30 pounds.
  • the OxygenTM strings are made from hundreds of composite microfibers bonded together.
  • a test apparatus 1000 was constructed to perform the tests on the vibration damping qualities of the grommets with elongated barrels.
  • Commercial embodiments of racquets 200 (Fig. 2) and 298 (Fig.3) were tested.
  • the racquet being tested was positioned in the fixture 1000 and held in a fixed position. In the fixed position, the racquet frame 102 did not move, only the strings moved when struck with a ball.
  • a Pro Penn HD racquetball ball with a diameter of 2.5 inches and a weight of 1.4 ounces was dropped from a fixed position height 1002 of two feet and oriented to strike a point 206 equidistant from both sides of the racquet frame and four inches from the top of the frame 102.
  • the vibration was measured via a microphone 1004 (Fig. 11) located five inches above the string bed just above the top of the racquet frame 102.
  • the microphone 1004 identified sound waveforms caused by vibration when the racquet was struck with the ball.
  • the microphone 1004 was connected to a computer that was using a software bundle called NCH Audio Essentials 2012 Edition which includes the following sub-programs:
  • Figure 14 shows a racquet similar to that tested in Figure 13, the only difference being that the barrels used in this racquet have an internal diameter of 2.6 mm rather than 1.5 - 1.6mm. There is a noticeable increase in dampening characteristic and the dampening is also superior to the shorter- and thinner-barrel version tested in Figure 12.
  • Figures 15 - 17 show similar vibration test data, for a racquet strung with 17 gauge string rather than a 16 gauge string. The improvement in dampening is still present as seen in Figure 17, although the improvement is not as dramatic as that seen for 16 gauge string.
  • Figures 18 - 20 record the same data for racquets in which 18 gauge string is used.
  • increasing the diameter of the longer-length barrels (Fig. 20) produces a dampening that is better than that produced by the narrow long barrels seen in Figure 19.
  • Figures 21 - 29 display data from intentionally off-center hits, and correspond to the data for center hits appearing in Figures 12— 20. For each of these experiments, a ball was dropped on location 208 on the racquet. This set of data is useful for analyzing the "stability" of the racquet, which is its propensity to behave in a more uniform way regardless of where on the string bed the ball hits.
  • Figures 21 - 23 are racquets strung with 16-gauge string and may be compared with Figures 12 - 14. The differences between a center hit and an off-center hit on a racquet equipped with narrow long barrels (1.5 - 1.6 mm interior diameter; Figures 13 and 22) are noticeable. Increasing the internal diameter of these barrels to 2.6 mm ( Figures 14 and 23) makes this difference go away, and thus a more "stable" racquet results. This effect is most pronounced in racquets strung with 16 - gauge string.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biophysics (AREA)
  • Professional, Industrial, Or Sporting Protective Garments (AREA)
  • Vibration Prevention Devices (AREA)

Abstract

L'invention concerne une raquette de sport ayant un amortissement de vibration de corde amélioré, qui comprend des œillets ayant des tubes allongés sur la plupart des travers. Le diamètre interne des tubes est choisi de façon à conserver un jeu minimal entre le travers et son tube de fermeture, en atténuant ainsi une vibration. Les longueurs de tube varient en fonction de leur distance à partir du haut du cadre, de telle sorte que leurs extrémités libres sont positionnées près de la corde principale la plus proche.
EP14795419.2A 2013-05-09 2014-05-08 Raquette ayant des tubes d' illet allonges ayant des caractéristiques d'amortissement améliorées Withdrawn EP2994207A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US13/890,846 US20140335979A1 (en) 2013-05-09 2013-05-09 Racquet having elongated grommet barrels with improved damping characteristics
PCT/US2014/037241 WO2014182869A1 (fr) 2013-05-09 2014-05-08 Raquette ayant des tubes d'œillet allonges ayant des caractéristiques d'amortissement améliorées

Publications (2)

Publication Number Publication Date
EP2994207A1 true EP2994207A1 (fr) 2016-03-16
EP2994207A4 EP2994207A4 (fr) 2017-01-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP14795419.2A Withdrawn EP2994207A4 (fr) 2013-05-09 2014-05-08 Raquette ayant des tubes d' illet allonges ayant des caractéristiques d'amortissement améliorées

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JP5992471B2 (ja) * 2014-05-20 2016-09-14 ヨネックス株式会社 ラケット、および、グロメット
US11612792B2 (en) * 2020-09-22 2023-03-28 Paul Marshall Pickleball paddle assembly
US20220203188A1 (en) * 2020-12-29 2022-06-30 East Coast Dyes, Inc. Clear lacrosse head

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JPH0751407A (ja) * 1993-08-20 1995-02-28 Bridgestone Sports Co Ltd ラケット
JP4143725B2 (ja) * 2004-02-27 2008-09-03 Ｓｒｉスポーツ株式会社 テニスラケット
US20060172827A1 (en) * 2005-01-28 2006-08-03 Soekahar Frans J String dampered with variable weight & balance racket sports
US8834306B2 (en) * 2011-07-20 2014-09-16 Ef Composite Technologies, L.P. Racquet with elongated grommet barrels

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EP2994207A4 (fr) 2017-01-11
US20140335979A1 (en) 2014-11-13
CA2911911A1 (fr) 2014-11-13
KR20160005121A (ko) 2016-01-13
JP2016521182A (ja) 2016-07-21
WO2014182869A1 (fr) 2014-11-13

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