Patent Application
20240050812
The present invention relates generally to a sports racquet. In particular, the present invention relates to racquet configured with reduced resistance to bending about a longitudinal axis of the racquet in a first direction that is parallel to a string bed of the racquet and perpendicular to the longitudinal axis, while maintaining a high level of resistance to bending about a longitudinal axis in a second direction that is perpendicular to the string bed of the racquet and maintaining a high level of torsional stability.
Sport racquets, such as tennis racquets, are well known and typically include a frame having a head portion coupled to a handle portion by a throat portion. The head portion supports a string bed having a plurality of main string segments alternately interwoven with a plurality of cross string segments.
Players generally continually seek more control, more power and/or a better feel from their racquets. Highly skilled tennis players typically seek to impart spin onto the tennis ball when impacting the ball. The ability to impart a spin (a top spin or a back spin) to a ball increases a player's ability to control the ball and to hit the ball with more power during play. For example, imparting a top spin onto a tennis ball can enable a player to swing faster, hit the tennis ball harder and still keep the tennis ball in play within the court. Imparting a top spin to a ball can enable a player to aim higher, swing faster, clear the net and keep the ball in play. Skilled tennis players also seek a racquet that provides the sense or feel of an increased “dwell time” or contact time between the racquet and the ball upon impact. The increased dwell time improves not only the responsiveness of a racquet, but also its control, including the ability to impart spin on the ball. The swing used by highly skilled tennis players to impart a top spin on to a tennis ball includes an upward sweeping motion in combination with the forward swinging motion. Such a top spin swing is more difficult to perform well than a more horizontal swing because the upward and forward motion of the head portion of the racquet during a top spin swing results in a shorter time window for impacting the ball. The upward sweeping motion of a racquet swing used to impart a top spin onto a ball also produces more of a lateral load onto the racquet during impact.
Racquets are continually designed in an effort to improve performance and playability of the racquet. Many existing racquets include high racquet frame beam heights and other racquet geometries that increase the racquet stiffness in an effort to improve the performance of the racquet. Other existing racquets incorporate a larger sized hoop portion supporting a larger sized string bed (i.e., a larger head size) in an effort to increase the size of the string bed and the racquet's performance. However, as the head size of a racquet increases, so does the polar moment of inertia of the racquet. A racquet with a higher polar moment of inertia can be more difficult to maneuver, particularly at the net or upon return of serve, than a racquet with a lower moment of inertia. Other existing racquets include designs that seek to lengthen the main and cross string segments comprising the string bed in an effort to increase the performance of the racquet. However, there continues to be a need for a racquet that further improves the performance and playability of the racquet.
There is a continuing need to provide a racquet that offers improved performance such as increased control, increased power, and/or improved feel. There is an ongoing need to provide an improved racquet design that seeks to improve all forms of racquet swing motions, including the upward sweeping motion of a topspin swing. There is a continuing need for a racquet having a string bed with an enlarged sweet spot and providing an increased “dwell time,” without negatively effecting the overall performance of the racquet. It would be advantageous to provide a racquet with an enlarged sweet spot and an increased “dwell time” without increasing the polar moment of inertia of the racquet head and without negatively affecting the maneuverability of the racquet. There is also a need for a racquet having a string bed with an enlarged sweet spot that is not a radical departure in look and design from traditional sport racquet designs.
The present invention provides a tennis racquet extending along a longitudinal axis and capable of being tested under a lateral bending test and a forward/rearward bending test. The racquet lateral bending test and the racquet forward/rearward bending test include a first test fixture having a handle portion contact surface, a first clamp and a deflection indicator. The racquet lateral bending test further includes a second clamp. The racquet lateral bending test involves securely mounting the racquet in a first orientation to the first test fixture at a first longitudinal location, attaching the second clamp to the racquet at a second location, operably engaging the deflection indicator to the second clamp, applying a first predetermined weight of 3 Kg to the racquet at a third location, and removing the first predetermined weight to obtain a lateral deflection measurement of the racquet with respect to the longitudinal axis. The racquet forward/rearward bending test involves securely mounting the racquet in a second orientation to the first test fixture at the first longitudinal location, applying a second predetermined weight of 2.8 Kg to the racquet at a fourth location, operably engaging the deflection indicator to the racquet at a fifth location, and removing the second predetermined weight to obtain a forward/rearward deflection measurement with respect to the longitudinal axis. The racquet is rotated 90 degrees about the longitudinal axis from the first orientation to the second orientation.
The racquet includes a frame including a head portion, a handle portion including a proximal end, and a throat portion positioned between the head portion and the handle portion. The head portion forms a hoop that defines a string bed plane, and the throat portion includes a pair of throat elements. At least the head portion and the throat portion of the frame of the racquet are formed at least in part of a fiber composite material. When the racquet is in the first longitudinal location on the first test fixture, the proximal end of the handle portion contacts the handle portion contact surface of the first test fixture and the first clamp of the first test fixture securely mounts the handle portion to the first test fixture including up to a first length that is six inches from the proximal end of the handle portion along the longitudinal axis of the bat. When the racquet is tested under the racquet lateral bending test, the racquet has a lateral deflection of at least 6.5 mm when measured in a first direction that is parallel to the string bed plane and perpendicular to the longitudinal axis. The first longitudinal location of the racquet is adjacent to the proximal end of the handle portion with the proximal end of the handle portion contacting of the handle portion contact surface of the first test fixture. The second location is at a distal end region of the head portion at a 12 o'clock position of the hoop. The third location is positioned at a side region of the head portion at the 3 o'clock position of the hoop at a distance that is 20 inches from the proximal end of the racquet along the longitudinal axis. The fourth and fifth locations are at a distal end region of the head portion at a 12 o'clock position of the hoop. When the racquet is tested under the racquet forward/rearward bending test, the racquet has a forward/rearward deflection with respect to the longitudinal axis of less than 7.3 mm when measured in a second direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis.
According to a principal aspect of a preferred form of the invention, a tennis racquet extending along a longitudinal axis. The racquet includes a frame including a head portion, a handle portion including a proximal end, and a throat portion positioned between the head portion and the handle portion. The head portion forms a hoop that defines a string bed plane. The head portion includes a distal region, first and second side regions, and a proximal region. The proximal region of the head portion includes a yoke. The throat portion includes a pair of throat elements extending from the handle portion and diverging away from the longitudinal axis toward the head portion. At least the head portion and the throat portion of the frame of the racquet are formed at least in part of a fiber composite material. Each of the throat elements merges with the head portion at the proximal region of head portion to form first and second transition regions. Each of the first and second transition regions include blend fillet at the string bed plane. The blend fillet forms a constant radius of less than or equal to 4 mm over an arc of at least 90 degrees.
This invention will become more fully understood from the following detailed description, taken in conjunction with the accompanying drawings described herein below, and wherein like reference numerals refer to like parts.
Referring to
The head portion 18 is a tubular structure that includes inner and outer peripheral walls 24 and 26. The head portion 18 can be broken down into regions, such as, a distal region 28, first and second side regions 30 and 32, and a proximal region 34, which collectively define a hoop 36 having a string bed area 38 for receiving and supporting the string bed 14. In one preferred implementation, the proximal region 34 includes a yoke 40. The string bed area 38 is also referred to as the head size of the racquet 10. In a preferred implementation, the head size or string bed area 38 of the racquet 10 is within the range of 93 to 120 square inches. In other implementations, the head size of the racquet 10 can be within the range 98 to 115 square inches. In other implementations, other head sizes can also be used and are contemplated under the present invention. The string bed area 38 has a maximum longitudinal dimension, a, and a maximum transverse dimension, b. The hoop 36 can be any closed curved shape including, for example, a generally oval shape, a generally tear-drop shape, a generally circular, a generally pear shape, and combinations thereof. In some implementations, the maximum longitudinal dimension a can be at least 1.2 times the maximum transverse dimension b (a≥1.2*b). In other implementations, the maximum longitudinal dimension a can be at least 1.25 times the maximum transverse dimension b (a≥1.25*b). In other implementations, the maximum longitudinal dimension a can be less than 1.2 times the maximum transverse dimension b.
The yoke 40 is an elongate tubular structural member that extends from the first side region 30 to the second side region 32 of the head portion 18. In one implementation, the yoke 40 is integrally formed with the frame 12 defining the proximal region 34. For example, the yoke can be formed of a fiber composite material and molded and cured with the frame 12 of the racquet 10. In alternative preferred implementations, the yoke 40 can be connected through use of adhesives, fasteners, bonding and combinations thereof. The yoke 40 is formed of a lightweight, durable material, such as a carbon-fiber composite material. Alternatively, the yoke 40 can be formed of other materials, such as, for example, other composite materials, metallic alloys, a polymeric material, wood and combinations thereof.
In a preferred implementation, the first and second side regions 30 and 32 downwardly extend from the head portion 18 to form first and second throat tubes 42 and 44 of the throat portion 22. The first and second throat tubes 42 and 44 converge and further downwardly extend to form the handle portion 20. Accordingly, in such implementations, the frame 12 can be formed of one continuous tube of material (e.g., fiber composite material) that is curved at its middle region to form the head portion 18 then each side of the continuous tube of material can converge toward each other in the throat region 22 and the end regions of the continuous tube can be arranged side by side to form the base structure of the handle portion 20. In such implementations, the frame 12 is formed as a one piece integral structure. The handle portion 20 can further include a pallet 46, a grip 48 and a butt cap 50.
In other implementations, the head portion 18 can be directly connected to one or both of the throat portion 22 and the yoke 40 through the use of conventional fasteners, adhesives, mechanical bonding, thermal bonding, or other combinations thereof. In one implementation, the head portion 18 can be separated from one or both of the throat portion and the yoke by a vibration and shock absorbing material, such as an elastomer.
The racquet 10 is configured for supporting a string bed 14 and is formed by a plurality of main string segments 52 alternately interwoven or interlaced with a plurality of cross string segments 54. The string bed 14 is preferably generally uniform with constant spacing between the string segments 52 and 54. Alternatively, the string bed 14 can have some spacing variability provided that the spacing of the main and cross string segments of the string bed is most dense at the center of the string bed 14 (or near the geometric center of the string bed or string bed area). The main and cross string segments 52 and 54 can be formed from one continuous piece of racquet string, or from two or more pieces of racquet string. The racquet string is formed of a high tensile strength, flexible material. In preferred implementations, the racquet string can be formed of a polyester material, a nylon, a natural gut material and/or a synthetic gut material. The racquet string can be formed in a monofilament construction or in a multiple-filament construction, and can be formed of various different diameters (or gauges). Preferably, the diameter of the racquet string is within the range 1.10 to 1.55 mm.
The inner and outer peripheral walls 24 and 26 of the hoop 36 can include string holes 59 for receiving the racquet string. The string holes 59 can be sized to be just larger than the diameter of the racquet string, or the combination of the racquet string and a grommet, or a size that is larger to accommodate movement or deflection of the racquet string and/or grommet. The head portion 18 of the racquet 10 can also include one or more grommets or bumper guards for supporting and protecting the racquet string as it extends from one string hole to another. Additionally, the number of string holes 59 can be varied to produce different string arrangements or numbers of main string segments 52 and cross string segments 54 resulting in different string patterns. Referring to
Referring to
Conventional tennis racquets are typically formed of fiber composite material and/or aluminum, and are typically formed to be stiff structures that resist deflection about the longitudinal axis of the racquet. A stiff racquet construction is generally considered to be desirable because it is believed to improve the power and/or control of the racquet. Conventionally, the stiffness of a racquet generally refers to the racquet's resistance to bending along the longitudinal axis of the racquet and with respect to the string bed plane in a forward/rearward direction with respect to the string bed. Racquet stiffness is typically measured in a forward/rearward bending test (or a racquet stiffness test) wherein the handle portion of the racquet is fixedly secured in a test fixture with the string bed (and the string bed plane) positioned generally horizontal to the ground, a load is applied to the distal region of the head portion in a direction that is perpendicular to the string bed plane. The load causes the racquet to bend, flex or deflect with respect to the longitudinal axis and the string bed plane. The amount of deflection is measured to ascertain the stiffness level of a racquet.
High quality racquets are also typically designed to provide high levels of torsional stability. A torsionally stable racquet resists rotational movement of the head portion of the racquet upon an off-center impact with a tennis ball which improves the control of the racquet. Accordingly, conventional racquet design seeks to produce racquets with high levels of racquet stiffness and torsional stability at a predetermined racquet weight or weight range.
The shape and geometry of the head portion 18 and the throat portion 22 of the frame 12 of the racquet 10 also contributes to the racquet's stiffness level and/or torsional stability. For example, racquets with high racquet beam heights are generally stiffer than racquets with lower racquet beam heights. The shape and geometry of the throat tubes 42 and 44 can also affect the stiffness of the racquet.
Contrary to conventional racquet design, the co-inventors of the present invention have identified and developed racquet constructions with increased racquet stiffness with respect to the longitudinal axis and the string bed plane of a racquet (increased forward/rearward bending stiffness in a direction perpendicular to the string bed plane 56 and parallel to second plane 58) and decreased lateral racquet stiffness with respect to the longitudinal axis and a second plane (bending in a direction that is parallel to the string bed plane), while maintaining desired levels of torsional stability. Contrary to conventional racquet design and expected results, the co-inventors of the present invention have discovered that racquets produced with decreased longitudinal deflection along the longitudinal axis of a racquet with respect to the string bed plane (increased bending stiffness in a direction perpendicular to the string bed plane) and increased longitudinal deflection along the longitudinal axis of the racquet with respect to the string bed plane (increased lateral deflection in a direction that is parallel to the string bed plane and perpendicular to the longitudinal axis) produce a significantly improved feel with improved control and/or increased power that many advanced players prefer. For example, implementations of the present invention with decreased flexibility with respect to the longitudinal axis 16 in a direction that is perpendicular to the string bed plane 56 and increased flexibility with respect to the longitudinal axis 16 in a direction that is parallel to the string bed plane 56 and perpendicular to the longitudinal axis 16), can improve the dwell time, control and performance of the racquet. In other implementations, with increased flexibility with respect to the longitudinal axis 16 in a direction that is parallel to the string bed plane 56 and perpendicular to the longitudinal axis 16, the racquets 10 can flex in response to a lateral load, such as the lateral load that is applied to the racquet upon execution of a top spin swing. The racquets of the present invention provide a significantly better feel, and a sensation of increased interaction with the ball particularly during topspin swings which can result in better control and increased power for the player.
In one implementation of the present invention, the shape and geometry of the throat tubes 42 and 44 contribute to the flexibility of the racquet 10 with respect deflection of the racquet 10 in a direction that is parallel to the string bed plane 56 and perpendicular to the longitudinal axis 16, while contributing to the torsional stability of the racquet 10. In another implementation of the present invention, the lay-up of the fiber composite material used to form the head portion 18 and the throat portion 22 contributes to the enhanced flexibility of the racquet 10 in a direction that is parallel to the string bed plane 56 and perpendicular to the longitudinal axis 16 while maintaining a high level of torsional stability and a high level of resistance to bending in a forward/rearward direction (a direction that is perpendicular to the string bed plane 56 and to the longitudinal axis 16).
As used herein, the term “fiber composite material” or “composite material” refers to a plurality of fibers within and permeated throughout a resin. The fibers can be co-axially aligned in sheets, layers or plies, or braided or weaved in sheets or layers, and/or chopped and randomly dispersed in one or more layers. A single ply typically includes hundreds or thousands of fiber bundles that are initially arranged to extend coaxially and parallel with each other through the resin that is initially uncured. Each of the fiber bundles includes a plurality of fibers. The fibers are formed of a high tensile strength material such as carbon. Alternatively, the fibers can be formed of other materials such as, for example, glass, graphite, boron, basalt, carrot, Kevlar®, Spectra®, poly-para-phenylene-2, 6-benzobisoxazole (PBO), hemp, flax, other natural fibers and combinations thereof. In one set of preferred implementations, the resin is preferably a thermosetting resin such as an epoxy or a polyester resin. In other sets of preferred implementations, the resin can be a thermoplastic resin. The composite material is typically wrapped about a mandrel and/or a comparable structure, and cured under heat and/or pressure. While curing, the resin is configured to flow and fully disperse and extend throughout the matrix of fibers. In multiple layer or ply constructions, the fibers can be aligned in different directions with respect to the longitudinal axis 16, and/or in braids or weaves from layer to layer.
Referring to
Conventional fiber composite racquets are formed of fiber composite layers including plies having angular pluralities of 30 degrees or less, with the exception of a small percentage of layers having a 90 degree ply. The use of layers having plies of angular values of 30 degrees or less are used because layups including such arrangements of layers can provide the desired high levels of stiffness and also result in less manufacturing waste when preparing or cutting plies from large uncut sheets of fiber composite material. Conventional racquet design teaches away from plies having angular polarities of greater than 30 degrees because such higher angled plies would negatively affect the stiffness of the racquet and would result in unnecessary material waste that would unnecessarily increase the manufacturing cost of the racquet.
During heating/molding and curing, the resin 54 can flow between plies 62 and within the fiber bundles 66. The plies 62 preferably typically have a thickness within the range of 0.002 to 0.018 inch. In other implementations, other thickness ranges can also be used.
Referring to
Referring to
The mandrel 74 is a body that is generally shaped to form the internal surface of the molded component and serves as a core upon which the layers 60 of fiber composite material can be wrapped or applied over. In one implementation, the mandrel 74 is an elongate body having a generally rectangular cross-sectional area with rounded corners. In other implementations, the mandrel can have other cross-sectional shapes. A bladder 76 is placed over, and fits around the outer surface of, the mandrel 74. Each layer 60 is wrapped or formed about a bladder 76 and mandrel 74 and follows the form or shape of the bladder 76 and mandrel 74. In the example arrangement of
In other implementations, other numbers of layers 60, lengths of layers 60 and angular orientations of layers 60 can be used. In implementations of the present invention, a plurality of the layers 60 (or ply arrangements) include high angle plies, meaning plies having angles greater than or equal to 35 degrees with respect to the composite axis 70. In one implementation, at least two layers (or ply arrangements) in a lay-up 80 (see
In other implementations, the lay-up 80, or plurality of ply arrangements, can include at least five layers 60, at least six layers 60, at least seven layers 60 and higher. In such lay-ups, the number of layers 60 being at least 35 degree angles can be at least three layers, or four layers, or five layers or more layers. In other implementations, the lay-up 80 or plurality of ply arrangements can include at least five layers 60, at least six layers 60, at least seven layers 60 and higher, and the number of layers 60 being at least 40 degree angles can be at least three layers, or four layers, or five layers or more layers. In still other implementations, the lay-up 80 or plurality of ply arrangements can include at least five layers 60, at least six layers 60, at least seven layers 60 and higher, and the number of layers 60 being at least 45 degree angles can be at least three layers, or four layers, or five layers or more layers.
In preferred implementations, the length of the high angle layers (at least 35 degree angle layers, at least 40 degree angle layers, or at least 45 degree angle layers) extend over at least 40 percent of the total length of the lay-up the head portion 18 of the racquet 10. In other implementations, the length of the high angle layers extend over at least 50 percent of the total length of the lay-up the head portion 18 of the racquet 10. In other implementations, the length of the high angle layers extend over at least 70 percent of the total length of the lay-up the head portion 18 of the racquet 10. In preferred implementations, the length of the layers 60 or ply arrangements can be sufficiently long such that, when molded and cured, the high angle layers (at least 35 degree angle layers, at least 40 degree angle layers, or at least 45 degree angle layers) extend over at least the head portion 18 of the racquet 10. In other implementations, the length of the layers 60 or ply arrangements can be sufficiently long such that, when molded and cured, the high angle layers (at least 35 degree angle layers, at least 40 degree angle layers, or at least 45 degree angle layers) extend over at least the head portion 18 and the throat portion 22 of the racquet 10.
In one implementation, the lay-up 80, or plurality of ply arrangements, can include a plurality of 0 degree plies 60g. A 0 degree ply 60g is a ply of fiber composite material having an arrangement of fibers 64 and fiber bundles 66 in a resin 68, wherein the fibers 64 and the fiber bundles 66 are arranged and aligned such that the fibers 64 and the fiber bundles 66 generally extend coaxially with respect to each other and are generally parallel to one another. The 0 degree plies 60g include fibers 64 or fiber bundles 66 that are formed such that they extend along the ply 62 at a zero angle or in a direction that is substantially parallel to the composite axis 70.
In one implementation, the lay-up or plurality of ply arrangements includes at least two 0 degree plies 60g and the length of the plies extend over at least 40 percent of the total length of the lay-up the head portion 18 of the racquet 10. In other implementations, the length of the 0 degree plies 60g can extend over at least 50 percent of the total length of the lay-up the head portion 18 of the racquet 10. In other implementations, the length of the 0 degree plies 60g can have a length of at least 80 cm. In other implementations, the length of the 0 degree plies 60g can extend over at least 70 percent of the total length of the lay-up the head portion 18 of the racquet 10. In other implementations, the length of the 0 degree plies 60g can have a length of at least 100 cm. In preferred implementations, the length of the 0 degree plies 60g can be sufficiently long such that, when molded and cured, the 0 degree plies 60g extend over at least the head portion 18 of the racquet 10. In other implementations, the length of the 0 degree plies 60g can be sufficiently long such that, when molded and cured, the 0 degree plies 60g extend over at least the head portion 18 and the throat portion 22 of the racquet 10. In one implementation, the lay-up includes at least two 0 degree plies 60g and at least two 45 degree ply arrangements, and each of the 0 degree plies and the 45 degree ply arrangements has a length of at least 80 cm. In another implementation, the at least two 0 degree plies and the at least two 45 degree ply arrangements have a length of at least 100 cm. In another implementation, the lay-up includes at least three 0 degree plies 60g and at least three 45 degree ply arrangements, and each of the 0 degree plies and the 45 degree ply arrangements has a length of at least 80 cm. In another implementation, the lay-up includes at least three 0 degree plies 60g and at least three 45 degree ply arrangements, and each of the 0 degree plies and the 45 degree ply arrangements extend over at least the head portion 18 of the racquet 10. In another implementation, the lay-up includes at least two 0 degree plies 60g and at least three 45 degree ply arrangements, and each of the 0 degree plies and the 45 degree ply arrangements extend over at least the head portion 18 and the throat portion 22 of the racquet 10.
In one implementation, at least 50 percent of the layers 60 of a lay-up or plurality of ply arrangements can be formed with carbon fibers. In another implementation, at least 75 percent of the layers 60 in a lay-up or ply arrangement can be formed of carbon fibers. In one implementation, each of the high angle layers (at least 35 degree angle layers, at least 40 degree angle layers, or at least 45 degree angle layers) in the lay-up 80 include a resin and have a fiber area weight of at least 100 g/m2. In another implementation, each of the high angle layers (at least 35 degree angle layers, at least 40 degree angle layers, at least 45 degree angle layers, or at least 60 degrees) in the lay-up 80 include a resin and have a fiber area weight of at least 120 g/m2.
Referring to
In one implementation, the mandrel 74 may include a pull tab 82 for facilitating the pulling or removal of the mandrel 74 from the plurality of layers 60 wrapped about the bladder 76 and the mandrel 74. The lay-up 80 of
Referring to
Referring to
The incorporation of high angle layers 60 (at least 35 degree angle layers, at least 40 degree angle layers, at least 45 degree angle layers, or at least 60 degree angle layers) into the lay-up 80 of the frame 12 of the tennis racquet 10 provides unique combination of performance characteristics that unexpectedly and significantly improve the feel and playability of the racquet. The incorporation of high angle layers 60 into the lay-up 80 of the frame 12 of the tennis racquet 10 can result in the racquet 10 having a high, typical or low amount of deflection in a forward/rearward racquet stiffness test, a high amount of deflection in a lateral racquet stiffness test, while maintaining a high level of torsional stability under a racquet torsional stability test. The incorporation of high angle layers 60 into the lay-up 80 of the frame 12 of the tennis racquet 10 can also result in the racquet 200 (see
Racquets built in accordance with the present invention can provide a number of significant advantages to users of the racquets. Characteristics such as, (1) racquet deflection measured with respect to the longitudinal axis of the racquet in a forward/rearward direction with respect to the string bed plane 56 can by decreased, and (2) racquet deflection measured with respect to the longitudinal axis of the racquet in a lateral direction, a direction that is parallel to the string bed plane 56 and perpendicular to the longitudinal axis, can be substantially increased through use of racquets built in accordance with the present invention. Additionally, racquets built in accordance with the present invention exhibit desirable levels of torsional stability of the racquet. Further, racquets built in accordance with the present invention exhibit relatively low vibration levels contributing to improved feel of such racquets.
Racquets built in accordance with the present invention, when tested in a racquet lateral bending test, can provide a lateral deflection of at least 6.0 mm when measured in a direction that is parallel to the string bed plane and perpendicular to the longitudinal axis. Accordingly, racquets built in accordance with the present invention have a reduced resistance to bending with respect to the longitudinal axis in a direction parallel to the string bed plane and perpendicular to the longitudinal axis of at least 6.5 mm. In other implementations, a racquet built in accordance with the present invention, when tested in a racquet lateral bending test, can provide a lateral deflection of at least 7.0 mm when measured in a direction that is parallel to the string bed plane and perpendicular to the longitudinal axis. Additionally, in other implementations, a racquet built in accordance with the present invention, when tested in a racquet lateral bending test, can provide a lateral deflection of at least 7.5 mm when measured in a direction that is parallel to the string bed plane and perpendicular to the longitudinal axis. Still further, in other implementations, a racquet built in accordance with the present invention, when tested in a racquet lateral bending test, can provide a lateral deflection of at least 8.0 mm, or at least 8.5 mm, when measured in a direction that is parallel to the string bed plane and perpendicular to the longitudinal axis.
Racquets built in accordance with the present invention, when tested in a racquet forward/rearward bending test, can provide a forward/rearward deflection of less than 7.3 mm when measured in a direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis. Accordingly, racquets built in accordance with the present invention have a higher level of resistance to bending with respect to the longitudinal axis in a direction perpendicular to the string bed plane and perpendicular to the longitudinal axis. In other implementations, a racquet built in accordance with the present invention, when tested in a racquet forward/rearward bending test, can provide a forward/rearward deflection of less than 7.0 mm when measured in a direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis. In other implementations, a racquet built in accordance with the present invention, when tested in a racquet forward/rearward bending test, can provide a forward/rearward deflection of less than 6.5 mm when measured in a direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis. Additionally, in other implementations, a racquet built in accordance with the present invention, when tested in a racquet forward/rearward bending test, can provide a forward/rearward deflection of less than 6.0 mm when measured in a direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis. All of the above mentioned forward/rearward deflection values can be incorporated into racquets that also have high levels of lateral deflection, such as the values described above (e.g., lateral deflections greater than or equal to 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, and 8.5 mm).
Racquets built in accordance with the present invention, when tested in a racquet torsional stability test, can also provide an angular deflection of less than 5.5 degrees. In other implementations, a racquet built in accordance with the present invention, when tested in a racquet torsional stability test, can provide an angular deflection of no more than 5.0 degrees. In other implementations, a racquet built in accordance with the present invention, when tested in a racquet torsional stability test, can provide an angular deflection of no more than 4.0 degrees. In still other implementations, a racquet built in accordance with the present invention, when tested in a racquet torsional stability test, can provide an angular deflection of no more than 3.5 degrees. The high levels of torsional stability described above, can be incorporated into racquets that also have low levels of forward/rearward flexibility, and high levels of lateral flexibility, as described above.
Referring to
The first test fixture 102 includes a handle portion contact surface 103 upon which the proximal end 51 of the handle portion 20 contacts when the racquet 10 is positioned in the first orientation at the first location 104. In one implementation, the first test fixture 102 can include a pneumatic clamp 105. The pneumatic clamp 105 and the first test fixture 102 are sized such that, when in clamped position, the pneumatic clamp 105 securely mounts the handle portion 20 to the first test fixture 102. The pneumatic clamp 105 securely mounts the handle portion 20 such that the most distal point of the clamp 105 away from the proximal end 51 of the handle portion results in a first length, l1, from the handle portion contact surface 103 and from the proximal end 51 of the handle portion 20 along the longitudinal axis 16. The first length l1 is 6 inches. When the racquet is in the first longitudinal location on the first test fixture 102, the proximal end 51 of the handle portion 20 contacts the handle portion contact surface 103 and the clamp 105 of the first test fixture 102 securely mounts the handle portion 20 to the first test fixture 102 including up to the first length l1 of 6 inches from the proximal end 51 of the handle portion 20. Accordingly, the racquet 10 is unsupported by the clamp 105 beyond the first length l1 in a direction toward the head portion 18 of the racquet 10 along the longitudinal axis 16. In other implementations, other forms of clamps can be used. In other implementations other forms of test fixtures can be used. In such other implementations, the first length l1 is incorporated into such test fixture configurations. Referring to
Referring to
Referring to
Referring to
The inventors have discovered that designing a racquet with a high degree of lateral flexibility with a low degree of forward/rearward flexibility and a high level of torsional stability fits many tennis players needs. Racquets built in accordance with embodiments of the present invention provide these features.
Like the head portion 18, head portion 218 is a tubular structure that includes inner and outer peripheral walls 224 and 226. The head portion 218 can be broken down into regions, such as, a distal region 228, first and second side regions 230 and 232, and a proximal region 234, which collectively define a hoop 236 having a string bed area 238 for receiving and supporting the string bed 14. In one preferred implementation, the proximal region 234 includes a yoke 240. The string bed area 238 is substantially the same as the string bed area 38. The yoke 240 is an elongate tubular structural member that extends from the first side region 230 to the second side region 232 of the head portion 218. The yoke 240 is integrally formed with the frame 212. For example, the yoke can be formed of a fiber composite material and molded and cured with the frame 212. The yoke 240 is formed of a lightweight, durable material, such as a carbon-fiber composite material.
The first and second side regions 230 and 232 downwardly extend from the head portion 218 to form first and second throat tubes 242 and 244 of the throat portion 222. The first and second throat elements or tubes 242 and 244 converge and further downwardly extend to form the handle portion 220. The handle portion 220 can further include a pallet 246, a grip 48 (shown in
The throat portion 222 includes the pair of throat elements or tubes 242 and 244 that extend from the handle portion 220 and diverge away from the longitudinal axis 16 toward the head portion 218. Like the head and throat portions 18 and 22, the head portion 220 and the throat portion 222 of the frame 212 of the racquet 200 are formed at least in part of a fiber composite material. Each of the throat elements 242 and 244 merge with the head portion 220 at the proximal region 234 of head portion 220 to form first and second transition regions 260 and 262. Each of the first and second transition regions 260 and 262 include a blend fillet 264. The blend fillet 264 defines a constant radius R that extends over a circular arc, a. A shown in
Referring to
Referring to
The advantages of the present invention were illustrated by performance of the racquet lateral bending test, the racquet forward/rearward bending test and the racquet torsional stability test on racquets made in accordance with implementations of the present invention and on several existing racquet models. Table 1 below lists the results of the racquet lateral bending test, the racquet forward/rearward bending test and the racquet torsional stability test on a total of 27 existing, prior art racquet models, including 2 representative Wilson® Clash® tennis racquets models from the 2019 model year, and three 2022 model year Solinco Whiteout tennis racquets. All of the racquets were tested unstrung. Table 1 also lists the results of the racquet lateral bending test, the racquet forward/rearward bending test and the racquet torsional stability test of three prototype racquets built in accordance with implementations of the present invention (Hi Lsi Prototype 1, Hi Lsi Prototype 3 and Hi Lsi Prototype 2).
The existing, prior art racquets include several older racquet models and several current racquet models, all of which are formed at least in part of fiber composite material. The older racquet models tested included the following racquets: Wilson® Profile®; Wilson® Profile® Comp™, Wilson® Ultra® 2; Wilson® Ultra® 2 MP; Wilson® Ultra® 85; Wilson® Ultra® 100; Wilson® Galaxy™; Wilson® Hammer® 6.2; Wilson® ProStaff® 5.5 SI; Wilson® Sting™; Wilson® Aggressor® and Prince® Graphite MP. The Wilson® branded racquet models were produced from Wilson Sporting Goods Co. of Chicago, Illinois from the years 1980 to 2018. The Prince® Graphite MP racquet was produced in 1983 by ABG-Prince OPCO, LLC of New York, New York. The current prior art racquet models tested included the following racquets: Wilson® Blade® 98; Babolat® Pure Drive™; Babolat® Aero™; Head® Radical® Tour™; Head® Radical® MP and Prince® Tour™ 100. The Babolat® branded racquets were produced by Babolat VS of Lyon, France. The Head® branded racquets were produced by HEAD Sport GmbH of Kennelbach, Austria. The more recent prior art racquet models include: Wilson® Clash® models and Solinco Whiteout models.
The three Hi Lsi prototypes racquets include frames of fiber composite material including several 45 degree layers and a plurality of 0 degree plies. The three Hi Lsi Prototype racquets are all 27 inches in length. The head size or string bed area 38 of each of the three Hi Lsi Prototype racquets were 99 sq. inches.
The three Hi Lsi Prototype racquets exhibited exceptionally high lateral bending in the racquet lateral bending test compared to existing, earlier racquets. The three Hi Lsi Prototype racquets demonstrated lateral deflection values of 7.7 mm, 7.8 mm and 8.0 mm. The lowest lateral deflection reading of the three Hi Lsi prototype racquets (the Flex Prototype 3) was over 35 percent greater than the highest lateral deflection value of the 19 existing, prior art racquet models. The other two Hi Lsi prototype racquets exhibited a lateral deflection values that are at least 37 percent greater than the highest lateral deflection value of the 19 existing, earlier racquet models, respectively. The three Hi Lsi Prototype racquets also have lateral deflection values that are greater than the recent prior art racquets.
Importantly, when the three Hi Lsi prototype racquets were tested under the racquet forward/rearward bending test, the three Hi Lsi prototype racquets have forward/rearward deflection values with respect to the longitudinal axis that are less than 7.3 mm, when measured in a second direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis. The three Hi Lsi prototype racquets have forward/rearward deflection values of 6.1, 6.0 and 6.2, which is over 43 percent less than the Wilson® Clash® racquet and over 16 percent less than the Solinco Whiteout racquets. Although many the 19 existing, earlier racquet models have forward/rearward deflection values that are similar or lower than the three Hi Lsi prototype racquets, these existing earlier racquet models also have very low lateral deflection values.
The results of testing the Hi Lsi prototype racquets and 19 existing prior art racquet under the racquet torsional stability test demonstrates that despite the exceptionally and uniquely high lateral bending flexibility, the Hi Lsi prototype racquets maintain a high level of torsional stability. The Hi Lsi prototype racquets provided unprecedented combinations of high levels of lateral flexibility and low levels of forward/rearward flexibility while maintaining a desirable level of torsional stability. The three Hi Lsi prototype racquets also provide exceptional feel, with increased levels of control, particularly for players who impart spin onto the ball during play, while maintaining a high level of torsional stability. With a high level of torsional stability, racquets built in accordance with the present invention, provide exceptional control even on off-center hits. The three Hi Lsi prototype racquets exhibited torsional deflection measurements under the racquet torsional stability test of 4.4 degrees, 3.05 degrees and 3.85 degrees.
A modal analysis was performed on the three prototype racquets built in accordance with implementations of the present invention and the existing prior art racquets. Referring to
The modal analysis vibration results of prior art racquets and the three Hi Lsi prototype racquets are shown in Table 2 below. The three Hi Lsi prototype racquets exhibit vibration values of 164 Hz, 156 Hz and 166 Hz.
The incorporation of the present invention significantly improves the racquet's performance by increasing the lateral flexibility of the racquet while maintaining a high level of torsional stability and a low level of forward/rearward flexibility. Racquets built in accordance with the present invention provide a racquet with better feel and increased dwell time for the player, particularly for players who seek to impart a topspin onto a ball during play. Racquets built in accordance with the present invention address the lateral load that is applied to the racquet during the performance of a topspin swing and flex to improve the playability and performance of the racquet during such topspin swings, while maintaining a low level of forward/rearward flexibility. The present invention provides a racquet with increased lateral flexibility and reduced levels of racquet vibration while maintaining high levels of torsional stability and a low level of forward/rearward flexibility. Racquets built in accordance with the present invention improve the playability and performance of the racquet without requiring a significantly larger head size negatively affecting the moment of inertia of the racquet. The result is a significantly improved racquet that is particularly suited for highly skilled players.
While the preferred implementations of the present invention have been described and illustrated, numerous departures therefrom can be contemplated by persons skilled in the art. Therefore, the present invention is not limited to the foregoing description but only by the scope and spirit of the appended claims.
