RACKET

Abstract

A face of a tennis racket includes a plain weave structure including a plurality of longitudinal threads, a plurality of high-tension transverse threads 36, and a plurality of low-tension transverse threads 38. The tennis racket includes a spin facilitating zone 46. The spin facilitating zone 46 includes: (1) a first high-tension transverse thread 36; (2) a second high-tension transverse thread 36; and (3) an odd number of low-tension transverse threads 38 positioned between the first high-tension transverse thread 36 and the second high-tension transverse thread 36. The spin facilitating zone includes no other high-tension transverse thread 36 positioned between the first high-tension transverse thread 36 and the second high-tension transverse thread 36.

Claims

1. A racket comprising: a head including a top and a bottom; and a face whose contour is formed by the head, wherein the face includes a plain weave structure including a plurality of longitudinal threads, a plurality of high-tension transverse threads, and a plurality of low-tension transverse threads, the plain weave structure includes one or more spin facilitating zones, each spin facilitating zone includes: (1) a first high-tension transverse thread; (2) a second high-tension transverse thread; and (3) an odd number of low-tension transverse threads positioned between the first high-tension transverse thread and the second high-tension transverse thread, and the spin facilitating zone includes no other high-tension transverse thread positioned between the first high-tension transverse thread and the second high-tension transverse thread.

2. The racket according to claim 1, wherein in the spin facilitating zone, the odd number of low-tension transverse threads positioned between the first high-tension transverse thread and the second high-tension transverse thread is one.

3. The racket according to claim 1, wherein a difference (T2T3) between a tension T2 of the high-tension transverse threads and a tension T3 of the low-tension transverse threads is greater than or equal to 10 pounds.

4. The racket according to claim 1, wherein a ratio (T2/T3) of a tension T2 of the high-tension transverse threads to a tension T3 of the low-tension transverse threads is greater than or equal to 1.2.

5. The racket according to claim 1, wherein a difference (T1T3) between a tension T1 of the longitudinal threads and a tension T3 of the low-tension transverse threads is greater than or equal to 5 pounds.

6. The racket according to claim 1, wherein a ratio (T1/T3) of a tension T1 of the longitudinal threads to a tension T3 of the low-tension transverse threads is greater than or equal to 1.1.

7. The racket according to claim 1, wherein the one or more spin facilitating zones include at least one spin facilitating zone that is positioned on a top side of the head with respect to a center point of the head.

8. The racket according to claim 7, wherein a number Nt of spin facilitating zones positioned on the top side of the head with respect to the center point of the head is greater than a number Nb of spin facilitating zones positioned on a bottom side of the head with respect to the center point of the head.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is an exploded front view showing a tennis racket according to one embodiment.

[0007] FIG. 2 is a side view showing the tennis racket of FIG. 1.

[0008] FIG. 3 is an exploded view showing part of the tennis racket of FIG. 1 in an enlarged manner.

[0009] FIG. 4 is an enlarged view showing part of a face of the racket of FIG. 1.

[0010] FIG. 5 is an enlarged front view showing a main string of the racket of FIG. 1.

[0011] FIG. 6 is an enlarged front view showing a high-tension cross string of the racket of FIG. 1.

[0012] FIG. 7 is an enlarged front view showing a low-tension cross string of the racket of FIG. 1.

[0013] FIG. 8 is an enlarged front view showing a head of the racket of FIG. 1 together with transverse threads.

[0014] FIG. 9 is an enlarged front view showing the head and the face of the racket of FIG. 1.

[0015] FIG. 10 is an enlarged view showing part of a cross section taken along line X-X in FIG. 9.

[0016] FIG. 11 is an enlarged view showing part of a cross section taken along line XI-XI in FIG. 9.

[0017] FIG. 12 is an enlarged view showing part of a cross section taken along line XII-XII in FIG. 9.

[0018] FIG. 13 is an enlarged view showing part of a cross section taken along line XIII-XIII in FIG. 9.

[0019] FIG. 14 is a front view showing a head of a tennis racket according to another embodiment together with transverse threads.

DETAILED DESCRIPTION

[0020] Hereinafter, preferred embodiments are described in detail with reference to the drawings as necessary.

[0021] FIGS. 1 to 3 each show a tennis racket 2. The tennis racket 2 includes a frame 4, a grip 6, an end cap 8, a grommet 10, and a face 12. The tennis racket 2 can be used in regulation-ball tennis. In FIGS. 1 and 2, an arrow X represents the width direction of the tennis racket 2; an arrow Y represents the axial direction of the tennis racket 2; and an arrow Z represents the thickness direction of the tennis racket 2. In FIG. 1, reference character CL indicates a center line of the tennis racket 2, the center line passing through the center of the tennis racket 2 in the width direction X.

[0022] The frame 4 includes a head 14, two throats 16, and a shaft 18. The head 14 forms the contour of the face 12. In the present embodiment, the front view shape of the head 14 is substantially an ellipse. The major axis direction of the ellipse coincides with the axial direction Y of the tennis racket 2. The minor axis direction of the ellipse coincides with the width direction X of the tennis racket 2. The head 14 includes a top 20 and a bottom 22. In FIG. 1, reference sign Pc indicates the center point of the head 14. The distance from the center point Pc to the bottom 22 is equal to the distance from the center point Pc to the top 20.

[0023] One end of each throat 16 is continuous with the head 14. Each throat 16, at the vicinity of the other end thereof, merges with the other throat 16. The throats 16 extend from the head 14 to the shaft 18. The shaft 18 extends from the location where the two throats 16 merge together. The shaft 18 is formed so as to be continuous with, and integrated with, the throats 16. A portion of the head 14, the portion being positioned between the two throats 16, is a yoke 24.

[0024] The frame 4 is hollow. The material of the frame 4 is a fiber reinforced resin. In the present embodiment, the matrix resin of the fiber reinforced resin is a thermosetting resin. The thermosetting resin is typically an epoxy resin. The fibers of the fiber reinforced resin are typically carbon fibers. The fibers are filament fibers.

[0025] As shown in FIG. 2, the head 14 includes a grommet groove 26. The grommet groove 26 is recessed from the outer peripheral surface of the head 14. As shown in FIG. 1, the grommet groove 26 is formed over substantially the entire periphery of the head 14, except the yoke 24.

[0026] As shown in FIG. 3, the head 14 includes a plurality of holes 28. Each hole 28 extends through the head 14. The plurality of holes 28 are arranged over substantially the entire periphery of the head 14.

[0027] The grip 6 is formed by a tape wound around the shaft 18. The grip 6 suppresses slip between a hand of a player and the tennis racket 2 when the tennis racket 2 is swung by the player. The end cap 8 is attached to the end of the grip 6.

[0028] As shown in FIG. 3, the grommet 10 includes a base 30 and a plurality of pipes 32. The base 30 is belt-shaped. Each pipe 32 is formed so as to be integrated with the base 30. Each pipe 32 rises from the base 30.

[0029] The material of the grommet 10 is typically a synthetic resin that is softer than the frame 4. The racket 2 may include a plurality of grommets 10. Each grommet 10 may be spaced apart from its adjacent grommet(s) 10. The number of pipes 32 of each grommet 10 may be one.

[0030] The grommet 10 is attached to the head 14. In a state where the grommet 10 is attached to the head 14, the base 30 is accommodated in the grommet groove 26. The base 30 may partly protrude from the grommet groove 26. In the state where the grommet 10 is attached to the head 14, the pipes 32 extend through the respective holes 28. Each pipe 32 is passed through a corresponding one of the holes 28.

[0031] FIG. 4 shows part of the face 12. The face 12 includes a plurality of longitudinal threads 34, a plurality of high-tension transverse threads 36, and a plurality of low-tension transverse threads 38. A tension T3 of the low-tension transverse threads 38 is less than a tension T2 of the high-tension transverse threads 36. Each longitudinal thread 34 is stretched on the head 14 in the axial direction Y. Each longitudinal thread 34 crosses the plurality of transverse threads (i.e., the transverse threads 36 and the transverse threads 38). Each high-tension transverse thread 36 is stretched on the head 14 in the width direction X. Each high-tension transverse thread 36 crosses the plurality of longitudinal threads 34. Each low-tension transverse thread 38 is stretched on the head 14 in the width direction X. Each low-tension transverse thread 38 crosses the plurality of longitudinal threads 34. The face 12 generally extends along an X-Y plane.

[0032] The tennis racket 2 includes a main string 40. The main string 40 is shown in FIG. 5. The main string 40 is stretched on the head 14 in a zigzag manner. The main string 40 is passed through the plurality of holes 28 (see FIG. 3). In other words, the main string 40 is passed through the plurality of pipes 32. The plurality of longitudinal threads 34 are formed by the main string 40. In the present embodiment, sixteen longitudinal threads 34 are formed by one main string 40. These longitudinal threads 34 are arranged symmetrically with respect to the center of the head 14 in the width direction. The tennis racket 2 may include a plurality of main strings 40.

[0033] The tennis racket 2 includes a high-tension cross string 42. The high-tension cross string 42 is shown in FIG. 6. The high-tension cross string 42 is stretched on the head 14 in a zigzag manner. The high-tension cross string 42 is passed through the plurality of holes 28 (see FIG. 3). In other words, the cross string is passed through the plurality of pipes 32. The plurality of high-tension transverse threads 36 are formed by the high-tension cross string 42. In the present embodiment, ten high-tension transverse threads 36 are formed by one high-tension cross string 42. The tennis racket 2 may include a plurality of high-tension cross strings 42. The high-tension cross string 42 may be integrated with the main string 40 (see FIG. 5).

[0034] The tennis racket 2 includes a low-tension cross string 44. The low-tension cross string 44 is shown in FIG. 7. In FIG. 7, the low-tension cross string 44 is illustrated as a dotted line to distinguish it from the high-tension cross string 42. The low-tension cross string 44 is stretched on the head 14 in a zigzag manner. The low-tension cross string 44 is passed through the plurality of holes 28 (see FIG. 2). In other words, the cross string is passed through the plurality of pipes 32. The plurality of low-tension transverse threads 38 are formed by the low-tension cross string 44. In the present embodiment, nine low-tension transverse threads 38 are formed by one low-tension cross string 44. The tennis racket 2 may include a plurality of low-tension cross strings 44.

[0035] FIG. 8 shows the high-tension cross string 42 and the low-tension cross string 44. As previously described, in the present embodiment, ten high-tension transverse threads 36 are formed by the high-tension cross string 42, and nine low-tension transverse threads 38 are formed by the low-tension cross string 44. Therefore, the number of transverse threads is nineteen. The holes 28 through which the high-tension cross string 42 is passed are selected, and also, the holes 28 through which the low-tension cross string 44 is passed are selected. Accordingly, in the face 12, the low-tension transverse threads 38 do not overlap the high-tension transverse threads 36. In the present embodiment, the high-tension transverse threads 36 and the low-tension transverse threads 38 are arranged alternately from the top 20 toward the bottom 22.

[0036] In FIG. 8, reference signs 46 each indicate a spin facilitating zone. In the present embodiment, the number of spin facilitating zones 46 is nine. Each spin facilitating zone 46 includes two high-tension transverse threads 36 and one low-tension transverse thread 38 positioned between these two high-tension transverse threads 36. The high-tension transverse thread 36 positioned between two spin facilitating zones 46 that are adjacent to each other belongs to one of these spin facilitating zones 46, and belongs also to the other spin facilitating zone 46.

[0037] FIG. 9 shows the head 14 and the face 12. The face 12 is formed by the plurality of longitudinal threads 34, the plurality of high-tension transverse threads 36, and the plurality of low-tension transverse threads 38. The face 12 includes a plain weave structure. With reference to FIG. 4 in addition to FIG. 9, it is clear that in the plain weave structure, each longitudinal thread 34 crosses the plurality of transverse threads in a manner to pass their front side and reverse side alternately. When the longitudinal thread 34 passes the front side of one of two transverse threads that are adjacent to each other, the longitudinal thread 34 passes the reverse side of the other one of the two transverse threads. On the other hand, when the longitudinal thread 34 passes the reverse side of one of two transverse threads that are adjacent to each other, the longitudinal thread 34 passes the front side of the other one of the two transverse threads. In the plain weave structure, each transverse thread crosses the plurality of longitudinal threads 34 in a manner to pass their front side and reverse side alternately. When the transverse thread passes the front side of one of two longitudinal threads 34 that are adjacent to each other, the transverse thread passes the reverse side of the other one of the two longitudinal threads 34. On the other hand, when the transverse thread passes the reverse side of one of two longitudinal threads 34 that are adjacent to each other, the transverse thread passes the front side of the other one of the two longitudinal threads 34. The tennis racket 2 including the plain weave structure can conform to the rules of the International Tennis Federation.

[0038] FIG. 10 shows part of a cross section taken along line X-X in FIG. 9. FIG. 10 shows one high-tension transverse thread 36 and five longitudinal threads 34. FIG. 10 shows the cross section of each longitudinal thread 34. Since the face 12 has the plain weave structure, the high-tension transverse thread 36 crosses the plurality of longitudinal threads 34 in a manner to pass their front side and reverse side alternately. The longitudinal threads 34 restrain the high-tension transverse thread 36. The high-tension transverse thread 36 restrains the longitudinal threads 34.

[0039] FIG. 11 shows part of a cross section taken along line XI-XI in FIG. 9. FIG. 11 shows one low-tension transverse thread 38 and five longitudinal threads 34. FIG. 11 shows the cross section of each longitudinal thread 34. Since the face 12 has the plain weave structure, the low-tension transverse thread 38 crosses the plurality of longitudinal threads 34 in a manner to pass their front side and reverse side alternately. The longitudinal threads 34 restrain the low-tension transverse thread 38. The low-tension transverse thread 38 restrains the longitudinal threads 34.

[0040] It is clear from comparison with FIG. 10 that the low-tension transverse thread 38 in FIG. 11 is bent to a greater degree than the high-tension transverse thread 36 in FIG. 10. This bending occurs as a result of receiving force from the longitudinal threads 34. Due to the tension T3 of the low-tension transverse thread 38 being less than the tension T2 of the high-tension transverse thread 36, the low-tension transverse thread 38 is bent to a greater degree than the high-tension transverse thread 36. The restraining force of the low-tension transverse thread 38 to restrain the longitudinal threads 34 is less than the restraining force of the high-tension transverse thread 36 to restrain the longitudinal threads 34.

[0041] FIG. 12 shows part of a cross section taken along line XII-XII in FIG. 9. FIG. 12 shows a first longitudinal thread 34a, four high-tension transverse threads 36, and three low-tension transverse threads 38. FIG. 12 shows the cross section of each transverse thread. Since the face 12 has the plain weave structure, the first longitudinal thread 34a crosses the transverse threads in a manner to pass their front side and reverse side alternately. In a case where it is assumed that the right side in FIG. 12 is the front side of the face 12 (hereinafter, the face side), the left side in FIG. 12 is the reverse side of the face 12 (hereinafter, the back side).

[0042] FIG. 12 shows a spin facilitating zone 46a (see also FIG. 8). The spin facilitating zone 46a includes a first high-tension transverse thread 36a and a second high-tension transverse thread 36b. The spin facilitating zone 46a further includes a first low-tension transverse thread 38a. The first low-tension transverse thread 38a is positioned between the first high-tension transverse thread 36a and the second high-tension transverse thread 36b. Between the first high-tension transverse thread 36a and the second high-tension transverse thread 36b, no other high-tension transverse thread 36 is present.

[0043] The first high-tension transverse thread 36a is positioned on the face side with respect to the first longitudinal thread 34a. The second high-tension transverse thread 36b is also positioned on the face side with respect to the first longitudinal thread 34a. The first low-tension transverse thread 38a is positioned on the back side with respect to the first longitudinal thread 34a. In the spin facilitating zone 46a, the first longitudinal thread 34a is exposed to the face side. Since the restraining force of the first low-tension transverse thread 38a to restrain the first longitudinal thread 34a is small, the degree of bending of the first longitudinal thread 34a in the spin facilitating zone 46a is small.

[0044] When hitting a drive shot, a tennis player swings the racket 2 such that the face 12 moves mainly in the width direction X. When the first longitudinal thread 34a collides with a tennis ball 48, force in the width direction X is exerted on the first longitudinal thread 34a. As mentioned above, the restraining force of the first low-tension transverse thread 38a to restrain the first longitudinal thread 34a is small. Accordingly, when the tennis ball 48 collides with the face side of the face 12, the first longitudinal thread 34a in the spin facilitating zone 46a receives the force from the tennis ball 48, and consequently, the first longitudinal thread 34a is sufficiently deformed in the width direction X. The first longitudinal thread 34a is restored after the deformation. The restoration imparts overspin to the tennis ball 48. This tennis racket 2 has excellent spin performance.

[0045] The degree of bending of the first high-tension transverse thread 36a and the degree of bending of the second high-tension transverse thread 36b are small (see FIG. 10). Therefore, these high-tension transverse threads 36 are less likely to hinder the deformation of the first longitudinal thread 34a.

[0046] FIG. 13 shows part of a cross section taken along line XIII-XIII in FIG. 9. Similar to FIG. 12, FIG. 13 shows the spin facilitating zone 46a. The spin facilitating zone 46a includes a first high-tension transverse thread 36a and a second high-tension transverse thread 36b. The spin facilitating zone 46a further includes a first low-tension transverse thread 38a. The first low-tension transverse thread 38a is positioned between the first high-tension transverse thread 36a and the second high-tension transverse thread 36b. Between the first high-tension transverse thread 36a and the second high-tension transverse thread 36b, no other high-tension transverse thread 36 is present. FIG. 13 further shows a second longitudinal thread 34b. The second longitudinal thread 34b is positioned adjacently to the first longitudinal thread 34a shown in FIG. 12 (see also FIG. 9).

[0047] The first high-tension transverse thread 36a is positioned on the back side with respect to the second longitudinal thread 34b. The second high-tension transverse thread 36b is also positioned on the back side with respect to the second longitudinal thread 34b. The first low-tension transverse thread 38a is positioned on the face side with respect to the second longitudinal thread 34b. In the spin facilitating zone 46a, the second longitudinal thread 34b is exposed to the back side. Since the restraining force of the first low-tension transverse thread 38a to restrain the second longitudinal thread 34b is small, the degree of bending of the second longitudinal thread 34b in the spin facilitating zone 46a is small.

[0048] As mentioned above, the restraining force of the first low-tension transverse thread 38a to restrain the second longitudinal thread 34b is small. Accordingly, when the tennis ball 48 collides with the back side of the face 12, the second longitudinal thread 34b in the spin facilitating zone 46a receives the force from the tennis ball 48, and consequently, the second longitudinal thread 34b is sufficiently deformed in the width direction X. The second longitudinal thread 34b is restored after the deformation. The restoration imparts overspin to the tennis ball 48. This tennis racket 2 has excellent spin performance.

[0049] The degree of bending of the first high-tension transverse thread 36a and the degree of bending of the second high-tension transverse thread 36b are small (see FIG. 10). Therefore, these high-tension transverse threads 36 are less likely to hinder the deformation of the second longitudinal thread 34b.

[0050] In the spin facilitating zone 46a, the plurality of longitudinal threads 34 exposed to the face side and the plurality of longitudinal threads 34 exposed to the back side are arranged alternately in the width direction X. The spin facilitating zone 46a facilitates spin in a case where the tennis ball 48 collides with the face side of the face 12, and also facilitates spin in a case where the tennis ball 48 collides with the back side of the face 12.

[0051] Each of the spin facilitating zones 46 shown in FIG. 8 facilitates spin in a case where the tennis ball 48 collides with the face side of the face 12, and also facilitates spin in a case where the tennis ball 48 collides with the back side of the face 12.

[0052] The high-tension transverse threads 36 whose tension T2 is high can contribute to the control performance of the tennis racket 2. The low-tension transverse threads 38 whose tension T3 is low can contribute to high launch speed of the tennis ball 48. Further, the low-tension transverse threads 38 can contribute also to a soft feel at impact of the tennis racket 2.

[0053] In light of spin performance, control performance, launch speed, and feel at impact, a tension difference (T2T3) is preferably greater than or equal to 10 pounds, more preferably greater than or equal to 15 pounds, and particularly preferably greater than or equal to 20 pounds. In light of the durability of the face 12, the difference (T2T3) is preferably less than or equal to 50 pounds, more preferably less than or equal to 40 pounds, and particularly preferably less than or equal to 35 pounds.

[0054] In light of spin performance, control performance, launch speed, and feel at impact, a tension ratio (T2/T3) is preferably greater than or equal to 1.2, more preferably greater than or equal to 1.3, and particularly preferably greater than or equal to 1.4. In light of the durability of the face 12, the ratio (T2/T3) is preferably less than or equal to 3.0, more preferably less than or equal to 2.7, and particularly preferably less than or equal to 2.5.

[0055] In light of control performance, the tension T2 of the high-tension transverse threads 36 is preferably greater than or equal to 40 pounds, more preferably greater than or equal to 45 pounds, and particularly preferably greater than or equal to 50 pounds. In light of launch speed and feel at impact, the tension T3 of the low-tension transverse threads 38 is preferably less than or equal to 50 pounds, more preferably less than or equal to 45 pounds, and particularly preferably less than or equal to 40 pounds.

[0056] When stretching the high-tension cross string 42 on the head 14, the tension T2 of the high-tension transverse threads 36 can be adjusted. When stretching the low-tension cross string 44 on the head 14, the tension T3 of the low-tension transverse threads 38 can be adjusted. The high-tension cross string 42 is not integrated with the low-tension cross string 44. Therefore, a decrease in the tension T2 of the high-tension transverse threads 36 will not cause an increase in the tension T3 of the low-tension transverse threads 38. Further, an increase in the tension T3 of the low-tension transverse threads 38 will not cause a decrease in the tension T2 of the high-tension transverse threads 36.

[0057] A tension T1 of the longitudinal threads 34 may be greater than the tension T2 of the high-tension transverse threads 36. The tension T1 of the longitudinal threads 34 may be equal to the tension T2 of the high-tension transverse threads 36. The tension T1 of the longitudinal threads 34 may be less than the tension T2 of the high-tension transverse threads 36 and greater than the tension T3 of the low-tension transverse threads 38. The tension T1 of the longitudinal threads 34 may be equal to the tension T3 of the low-tension transverse threads 38. The tension T1 of the longitudinal threads 34 may be less than the tension T3 of the low-tension transverse threads 38.

[0058] In a case where the tension T1 of the longitudinal threads 34 is equal to the tension T2 of the high-tension transverse threads 36, the plurality of longitudinal threads 34 and the plurality of high-tension transverse threads 36 may be formed by one string. In a case where the tension T1 of the longitudinal threads 34 is equal to the tension T3 of the low-tension transverse threads 38, the plurality of longitudinal threads 34 and the plurality of low-tension transverse threads 38 may be formed by one string.

[0059] Preferably, the tension T1 of the longitudinal threads 34 is greater than the tension T3 of the low-tension transverse threads 38. In light of spin performance, control performance, launch speed, and feel at impact, a tension difference (T1T3) is preferably greater than or equal to 5 pounds, more preferably greater than or equal to 10 pounds, and particularly preferably greater than or equal to 15 pounds. In light of the durability of the face 12, the difference (T1T3) is preferably less than or equal to 45 pounds, more preferably less than or equal to 35 pounds, and particularly preferably less than or equal to 30 pounds.

[0060] In light of spin performance, control performance, launch speed, and feel at impact, a tension ratio (T1/T3) is preferably greater than or equal to 1.1, more preferably greater than or equal to 1.2, and particularly preferably greater than or equal to 1.3. In light of the durability of the face 12, the ratio (T1/T3) is preferably less than or equal to 3.0, more preferably less than or equal to 2.7, and particularly preferably less than or equal to 2.5.

[0061] In the present embodiment, in each spin facilitating zone 46, the number of low-tension transverse threads 38 positioned between the first high-tension transverse thread 36 and the second high-tension transverse thread 36 is one. Alternatively, the number of low-tension transverse threads 38 positioned between the first high-tension transverse thread 36 and the second high-tension transverse thread 36 in each spin facilitating zone 46 may be an odd number different from one. Specifically, it may be three or five. Ideally, it is one.

[0062] Preferably, the material of each string is a synthetic resin or a natural material. Preferable examples of the synthetic resin include nylon and polyester. The natural material is preferably natural gut. The material of the high-tension cross string 42 may be the same as or different from the material of the main string 40. The material of the low-tension cross string 44 may be the same as or different from the material of the main string 40. The material of the low-tension cross string 44 may be the same as or different from the material of the high-tension cross string 42.

[0063] FIG. 14 shows part of a tennis racket 50 according to another embodiment. FIG. 14 shows a head 52, a plurality of high-tension transverse threads 54, and a plurality of low-tension transverse threads 56. Each high-tension transverse thread 54 is illustrated as a solid line, and each low-tension transverse thread 56 is illustrated as a dotted line. Similar to the tennis racket 2 shown in FIGS. 1 to 13, the tennis racket 50 includes a plurality of longitudinal threads. The illustration of the longitudinal threads is omitted in FIG. 14. Similar to the tennis racket 2 shown in FIGS. 1 to 13, the tennis racket 50 includes a grip, an end cap, a grommet, throats, a shaft, etc.

[0064] The tennis racket 50 includes three spin facilitating zones 58. Each spin facilitating zone 58 includes two high-tension transverse threads 54 and one low-tension transverse thread 56 positioned between these two high-tension transverse threads 54. Each spin facilitating zone 58 is positioned on the top side with respect to the center point Pc. Similar to the spin facilitating zones 46 shown in FIGS. 12 and 13, each spin facilitating zone 58 facilitates spin in a case where the tennis ball 48 collides with the face side of the face, and also facilitates spin in a case where the tennis ball 48 collides with the back side of the face.

[0065] When hitting a drive shot, the hitting point is often on the top side with respect to the center point Pc. The spin facilitating zones 58 positioned on the top side with respect to the center point Pc can contribute to the spin performance when hitting a drive shot.

[0066] The tennis racket 50 may include spin facilitating zones 58 positioned on the bottom side with respect to the center point Pc as well as the spin facilitating zones 58 positioned on the top side with respect to the center point Pc. The spin facilitating zone 58 that includes the center point Pc and whose center point in the axial direction Y is positioned on the top side with respect to the center point Pc is the spin facilitating zone 58 positioned on the top side with respect to the center point Pc. The spin facilitating zone 58 that includes the center point Pc and whose center point in the axial direction Y is positioned on the bottom side with respect to the center point Pc is the spin facilitating zone 58 positioned on the bottom side with respect to the center point Pc.

[0067] Preferably, the number Nt of the spin facilitating zones 58 positioned on the top side with respect to the center point Pc is greater than the number Nb of the spin facilitating zones 58 positioned on the bottom side with respect to the center point Pc. This tennis racket 50 is excellent in terms of spin performance when hitting a drive shot. A difference (NtNb) is preferably greater than or equal to 1, more preferably greater than or equal to 2, and particularly preferably greater than or equal to 3. In the embodiment shown in FIG. 14, the number Nt is 3, and the number Nb is 0. Accordingly, the difference (NtNb) is 3.

EXAMPLES

Example 1

[0068] The tennis racket shown in FIGS. 1 to 13 was fabricated. The racket included: longitudinal threads having the tension T1 of 50 pounds; high-tension transverse threads having the tension T2 of 60 pounds; and low-tension transverse threads having the tension T3 of 40 pounds.

Examples 2 to 4 and Comparative Examples 1 to 5

[0069] Tennis rackets of Examples 2 to 4 and Comparative Examples 1 to 5 were obtained in the same manner as Example 1, except that the tension of each type of threads was varied as shown in Tables 1 and 2.

[Hitting Test]

[0070] Advanced tennis players did a rally by using each tennis racket. The tennis players evaluated the flight performance, spin performance, feel at impact (softness), and control performance of each racket on the scale of 1 to 10. The evaluation results are shown in Tables 1 and 2 below.

TABLE-US-00001 TABLE 1 Evaluation Results Example Example Example Example 1 2 3 4 Tension (lbs) Longitudinal thread T1 50 40 60 60 High-tension 60 60 60 60 Transverse thread T2 Low-tension 40 40 40 30 Transverse thread T3 T1 T3 10 0 20 30 T2 T3 20 20 20 30 T1/T3 1.3 1.0 1.5 2.0 T2/T3 1.5 1.5 1.5 2.0 Evaluation Flight 7 8 6 7 Spin 8 7 9 9 Feel at impact 6 7 5 6 Control 7 6 8 7 Overall evaluation 7.0 7.0 7.0 7.3

TABLE-US-00002 TABLE 2 Evaluation results Comp. Comp. Comp. Comp. Comp. Example Example Example Example Example 1 2 3 4 5 Tension (lbs) Longitudinal 50 40 60 60 40 thread T1 High-tension 50 40 60 40 60 Transverse thread T2 Low-tension 50 40 60 40 60 Transverse thread T3 T1 T3 0.0 0.0 0.0 20.0 20.0 T2 T3 0.0 0.0 0.0 0.0 0.0 T1/T3 1.0 1.0 1.0 1.5 0.7 T2/T3 1.0 1.0 1.0 1.0 1.0 Evaluation Flight 6 9 4 6 6 Spin 5 3 5 3 6 Feel at 6 9 3 5 6 impact Control 6 3 9 7 4 Overall 5.8 6.0 5.3 5.3 5.5 evaluation

[0071] It is clear from Tables 1 and 2 that the tennis racket of each Example is excellent in terms of flight performance, spin performance, feel at impact (softness), and control performance. These evaluation results clearly indicate the superiority of the racket of each Example.

[Disclosure Items]

[0072] The following items each disclose a preferred embodiment.

[Item 1]

[0073] A racket including: a head including a top and a bottom; and a face whose contour is formed by the head. The face includes a plain weave structure including a plurality of longitudinal threads, a plurality of high-tension transverse threads, and a plurality of low-tension transverse threads. The plain weave structure includes one or more spin facilitating zones. Each spin facilitating zone includes: (1) a first high-tension transverse thread; (2) a second high-tension transverse thread; and (3) an odd number of low-tension transverse threads positioned between the first high-tension transverse thread and the second high-tension transverse thread. The spin facilitating zone includes no other high-tension transverse thread positioned between the first high-tension transverse thread and the second high-tension transverse thread.

[Item 2]

[0074] The racket according to item 1, wherein in the spin facilitating zone, the odd number of low-tension transverse threads positioned between the first high-tension transverse thread and the second high-tension transverse thread is one.

[Item 3]

[0075] The racket according to item 1 or 2, wherein a difference (T2-T3) between a tension T2 of the high-tension transverse threads and a tension T3 of the low-tension transverse threads is greater than or equal to 10 pounds.

[Item 4]

[0076] The racket according to any one of items 1 to 3, wherein a ratio (T2/T3) of a tension T2 of the high-tension transverse threads to a tension T3 of the low-tension transverse threads is greater than or equal to 1.2.

[Item 5]

[0077] The racket according to any one of items 1 to 4, wherein a difference (T1-T3) between a tension T1 of the longitudinal threads and a tension T3 of the low-tension transverse threads is greater than or equal to 5 pounds.

[Item 6]

[0078] The racket according to any one of items 1 to 5, wherein a ratio (T1/T3) of a tension T1 of the longitudinal threads to a tension T3 of the low-tension transverse threads is greater than or equal to 1.1.

[Item 7]

[0079] The racket according to any one of items 1 to 6, wherein the one or more spin facilitating zones include at least one spin facilitating zone that is positioned on a top side of the head with respect to a center point of the head.

[Item 8]

[0080] The racket according to item 7, wherein a number Nt of spin facilitating zones positioned on the top side of the head with respect to the center point of the head is greater than a number Nb of spin facilitating zones positioned on a bottom side of the head with respect to the center point of the head.

[0081] The racket as described above is suitable also for use in, for example, soft tennis, squash, and badminton. The above descriptions are merely illustrative examples, and various modifications can be made without departing from the principles of the present invention.