Patents by Inventor Takahiro Sajima

Takahiro Sajima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Golf ball
    Patent number: 8651978
    Abstract: The golf ball 2 has a northern hemisphere N and a southern hemisphere S. The northern hemisphere N is adjacent to the southern hemisphere S across an equatorial line Eq. Each of the northern hemisphere N and the southern hemisphere S has a pole vicinity region 14 and an equator vicinity region 16. Each of the pole vicinity region 14 and the equator vicinity region 16 has a large number of dimples. The dimple pattern of the pole vicinity region 14 includes three units that are rotationally symmetrical to each other about a pole Po. The dimple pattern of the equator vicinity region 16 includes six units that are rotationally symmetrical to each other about the pole Po. The sum (Ps+Pp) of a peak value Ps and a peak value Pp of the golf ball 2 is equal to or greater than 600 mm.
    Type: Grant
    Filed: June 30, 2010
    Date of Patent: February 18, 2014
    Assignee: SRI Sports Limited
    Inventors: Takahiro Sajima, Hirotaka Nakamura, Hyoungchol Kim
  • Golf ball
    Patent number: 8647219
    Abstract: Based on a surface shape appearing at a predetermined point moment by moment during rotation of a golf ball having numerous dimples on its surface, a data constellation regarding a parameter dependent on a surface shape of the golf ball is calculated. Preferably, the parameter is a distance between an axis of the rotation and the surface of the golf ball. Another preferable parameter is a volume of space between a surface of a phantom sphere and the surface of the golf ball. Based on a maximum value and a minimum value of the data constellation, a fluctuation range is calculated. By dividing the fluctuation range by a total volume of the dimples, an evaluation value is calculated. This value is calculated for each of PH rotation and POP rotation.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: February 11, 2014
    Assignee: SRI Sports Limited
    Inventors: Hyoungchol Kim, Takahiro Sajima, Kaname Yamada
  • GOLF BALL
    Publication number: 20130324321
    Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4. The cover 6 includes an inner cover 8 and an outer cover 10 positioned outside the inner cover 8. When distances (%) from a central point of the core 4 to nine points and hardnesses at the nine points, which nine points are obtained by dividing a region from the central point to a surface of the core 4 at intervals of 12.5% of a radius of the core 4, are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is 0.95 or greater. A hardness of an innermost layer of the cover 6 is greater than a surface hardness of the core 4. Preferably, the core is obtained by a rubber composition being crosslinked. The rubber composition includes an acid and/or a salt (d).
    Type: Application
    Filed: May 31, 2013
    Publication date: December 5, 2013
    Inventors: Takahiro SAJIMA, Hirotaka NAKAMURA
  • GOLF BALL
    Publication number: 20130324317
    Abstract: A golf ball 2 includes a core 4, an inner cover 6, and an outer cover 8. The core 4 includes a center 10, an inner envelope layer 12, and an outer envelope layer 14. The inner envelope layer 12 is formed by a rubber composition being crosslinked. The rubber composition includes: a base rubber (a); a co-crosslinking agent (b); a crosslinking initiator (c); and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms.
    Type: Application
    Filed: May 3, 2013
    Publication date: December 5, 2013
    Applicant: DUNLOP SPORTS CO. LTD.
    Inventors: Takahiro SAJIMA, Hidetaka INOUE
  • GOLF BALL
    Publication number: 20130324318
    Abstract: The present invention provides a golf ball comprising a golf ball body with a spherical core having one or more layers, an intermediate layer disposed outside the spherical core and a cover disposed outside the intermediate layer and a paint film formed on a surface of the golf ball body, and having a friction coefficient calculated using a contact force tester of 0.35 or more and 0.60 or less, wherein the golf ball body has specific plurality of dimples on the surface thereof, at least one layer of the spherical core is a rubber layer having a specific hardness distribution, and the rubber layer has a hardness at the outermost point which is greater than a hardness at the innermost point, and the intermediate layer has a slab hardness (Hm) which is greater than a slab hardness (Hc) of the cover.
    Type: Application
    Filed: May 31, 2013
    Publication date: December 5, 2013
    Inventors: Kazuhiko ISOGAWA, Kosuke TACHIBANA, Takahiro SAJIMA, Toshiyuki TARAO
  • GOLF BALL
    Publication number: 20130324314
    Abstract: A golf ball 2 includes a core 4 and a cover 6. The core 4 includes a center 8 and an envelope layer 10 each of which is formed by a rubber composition being crosslinked. At least one of the rubber compositions of the center 8 and the envelope layer 10 includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness H(Ie) at an innermost portion of the envelope layer 10 is greater than a hardness H(Sc) at an outermost portion of the center 8. A hardness Ho of the cover 6 is greater than a hardness Hs at a surface of the core 4.
    Type: Application
    Filed: April 19, 2013
    Publication date: December 5, 2013
    Applicant: Dunlop Sports Co. Ltd.
    Inventors: Hidetaka INOUE, Takahiro SAJIMA
  • GOLF BALL
    Publication number: 20130324319
    Abstract: An object of the present invention is to provide a golf ball having a novel core structure and traveling a great flight distance on driver shots. The present invention provides a golf ball comprising a core composed of a spherical center and an envelope layer and at least one cover layer disposed outside the core, wherein the spherical center has an internal hardness difference between a maximum hardness and a minimum hardness of less than 5 in JIS-C hardness, the envelope layer is formed from an envelope rubber composition containing (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) an crosslinking initiator and (d) an acid and/or a salt thereof, and the outermost cover layer has a highest hardness among the constituent members of the golf ball.
    Type: Application
    Filed: May 31, 2013
    Publication date: December 5, 2013
    Inventor: Takahiro SAJIMA
  • GOLF BALL
    Publication number: 20130316851
    Abstract: A golf ball 2 includes a core 4, an inner cover 6, and an outer cover 8. The core 4 includes a center 10 and an envelope layer 12. The envelope layer 12 is formed by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness Hi of the inner cover 6 is greater than a hardness Hs at a surface of the core 4. A hardness Ho of the outer cover 8 is less than the hardness Hi.
    Type: Application
    Filed: April 26, 2013
    Publication date: November 28, 2013
    Applicant: DUNLOP SPORTS CO.LTD.
    Inventors: Takahiro SAJIMA, Hidetaka INOUE
  • GOLF BALL
    Publication number: 20130316850
    Abstract: A golf ball 2 includes a core 4, an inner cover 8, a mid cover 10, and an outer cover 12. Nine points are determined by dividing a region from a central point of the core 4 to a surface of the core 4 at intervals of 12.5% of a radius of the core 4. When distances (%) from the central point to the nine points and hardnesses at the nine points are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95. A hardness Hi of the inner cover 8 is greater than a hardness Hs at the surface of the core 4. A hardness Ho of the outer cover 12 is greater than the hardness Hi. A difference (Hi?Hs) is 1 or greater. A difference (Ho?Hi) is 5 or greater but 30 or less.
    Type: Application
    Filed: March 14, 2013
    Publication date: November 28, 2013
    Applicant: DUNLOP SPORTS CO., LTD.
    Inventors: Hidetaka INOUE, Takahiro SAJIMA
  • Golf ball
    Patent number: 8409033
    Abstract: A golf ball 2 includes a center 12, a mid layer 14, a reinforcing layer 6, a cover 8 and a paint layer 10. The golf ball 2 has a large number of dimples 16 on the surface thereof. The cover 8 is formed of a resin composition including thermoplastic polyurethane (A) and a polyisocyanate mixture (B). The polyisocyanate mixture (B) includes a urethane prepolymer (B1) having two or more isocyanate groups or an isocyanate compound (B2) having three or more isocyanate groups. The polyisocyanate mixture (B) further includes a thermoplastic resin (B3) which substantially does not react with an isocyanate group. The golf ball 2 is obtained by a mold having protrusions which project from the equator of the mold. Each protrusion includes a part of a pimple.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: April 2, 2013
    Assignee: SRI Sports Limited
    Inventors: Keiji Ohama, Kazuya Kamino, Takahiro Sajima
  • Golf ball
    Patent number: 8409034
    Abstract: A golf ball 2 includes a center 12, a mid layer 14, a reinforcing layer 6, a cover 8 and a paint layer 10. The golf ball 2 has a large number of dimples 16 on the surface thereof. The cover 8 is formed of a resin composition including thermoplastic polyurethane (A) and a polyisocyanate mixture (B). The polyisocyanate mixture (B) includes a urethane prepolymer (B1) having two or more isocyanate groups or an isocyanate compound (B2) having three or more isocyanate groups. The polyisocyanate composition (B) further includes a thermoplastic resin (B3) which substantially does not react with an isocyanate goup. The golf ball 2 is obtained by a mold having protrusions which projects from the equator of the mold. Each protrusion includes a part of a pimple.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: April 2, 2013
    Assignee: SRI Sports Limited
    Inventors: Kazuya Kamino, Toshiyuki Tarao, Keiji Ohama, Takahiro Sajima
  • Golf ball
    Patent number: 8388466
    Abstract: A golf ball 2 includes a core 4, a cover 6, and a paint layer 8. The golf ball 2 has numerous dimples 10 on the surface thereof. The cover 6 is formed of a resin composition including thermoplastic polyurethane (A) and a polyisocyanate mixture (B). The polyisocyanate mixture (B) includes a polyisocyanate compound (B1) having two or more isocyanate groups or a urethane prepolymer (B2) having two or more isocyanate groups. The cover 6 has a hardness of 30 or greater and 55 or less. The cover 6 has a thickness of 1.0 mm or greater and 2.0 mm or less. The ratio of the total volume of all the dimples 10 to the surface area of a phantom sphere of the golf ball is less than 75%. The dimples 10 have a curvature radius at the edge thereof in a range of 0.1 mm to 10 mm.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: March 5, 2013
    Assignee: SRI Sports Limited
    Inventors: Keiji Ohama, Hirotaka Nakamura, Takahiro Sajima
  • GOLF BALL
    Publication number: 20130005507
    Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4. The cover 6 includes an inner cover 8 and an outer cover 10 positioned outside the inner cover 8. The core 4 is obtained by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and a carboxylate (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. The amount of the carboxylate (d) is equal to or greater than 1 parts by weight but less than 40 parts by weight per 100 parts by weight of the base rubber (a). A hardness of an innermost layer of the cover is greater than a surface hardness of the core.
    Type: Application
    Filed: April 26, 2012
    Publication date: January 3, 2013
    Inventors: Takahiro SAJIMA, Hirotaka Nakamura
  • GOLF BALL
    Publication number: 20130005505
    Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4 and including an inner cover 8 and an outer cover 10 positioned outside the inner cover 8. The core 4 is obtained by crosslinking a rubber composition. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and a carboxylate (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. The amount of the carboxylate (d) is equal to or greater than 1 parts by weight but less than 40 parts by weight per 100 parts by weight of the base rubber (a). A hardness of an innermost layer of the cover is equal to or less than a surface hardness of the core.
    Type: Application
    Filed: April 26, 2012
    Publication date: January 3, 2013
    Inventors: Takahiro Sajima, Hirotaka Nakamura
  • GOLF BALL
    Publication number: 20120270684
    Abstract: The surface of a golf ball 2 is divided by four comparting great circles CG into six spherical quadrangles Ss and eight spherical triangles St. The eight spherical triangles St are composed of four first spherical triangles St1 and four second spherical triangles St2. Dimple patterns of the six spherical quadrangles Ss are the same. Dimple patterns of the four first spherical triangles St1 are the same. Dimple patterns of the four second spherical triangles St2 are the same. The dimple pattern of each first spherical triangle St1 is different from the dimple pattern of each second spherical triangle St2. The comparting great circles CG are obtained by projecting the 24 sides of a cuboctahedron inscribed in a phantom sphere of the golf ball 2 on the surface of the phantom sphere.
    Type: Application
    Filed: April 4, 2012
    Publication date: October 25, 2012
    Inventors: Takahiro SAJIMA, Hirotaka NAKAMURA
  • GOLF BALL
    Publication number: 20120252604
    Abstract: An object of the present invention is to provide a golf ball having an improved controllability and shot feeling while maintaining a flight distance on driver shots. The present invention provides a golf ball having a core, an intermediate layer disposed around the core, and a cover disposed around the intermediate layer, wherein the core has a center and an envelope layer disposed around the center, and has a specific hardness distribution, and the intermediate layer is formed from an intermediate layer composition comprising, as a resin component, (A) a modified polyester elastomer and (B) a binary ionomer resin, and having a flexural modulus ranging from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a repulsive modulus of 55% or more, and a slab hardness ranging from 60 to 90 in JIS-hardness.
    Type: Application
    Filed: March 27, 2012
    Publication date: October 4, 2012
    Inventors: Satoko OKABE, Takahiro Sajima, Yoshiko Matsuyama
  • GOLF BALL
    Publication number: 20120165127
    Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Ce) of an amount of compressive deformation Co of the center 10 to an amount of compressive deformation Ce of the core 4 is greater than 2.0 but less than 3.0. The ratio (Vo/Ve) of the volume Vo of the center 10 to the volume Ve of the core 4 is equal to or greater than 0.01 but equal to or less than 0.13.
    Type: Application
    Filed: October 12, 2011
    Publication date: June 28, 2012
    Inventors: Takahiro SAJIMA, Yoshiko Matsuyama
  • GOLF BALL
    Publication number: 20120165126
    Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Do) of an amount of compressive deformation Co of the center 10 to the diameter Do of the center 10 is equal to or greater than 0.085 but equal to or less than 0.130. The ratio (Ce/De) of an amount of compressive deformation Ce of the core 4 to the diameter De of the core 4 is equal to or greater than 0.015 but equal to or less than 0.020.
    Type: Application
    Filed: October 12, 2011
    Publication date: June 28, 2012
    Inventors: Takahiro SAJIMA, Yoshiko Matsuyama
  • GOLF BALL
    Publication number: 20120165128
    Abstract: A golf ball 2 includes a core 4, amid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio (Do/De) of an amount of compressive deformation Do of the center 10 to an amount of compressive deformation De of the core 4 is equal to or greater than 1.5 but equal to or less than 2.5. The ratio (Do/Dc) of the amount of compressive deformation Do of the center 10 to an amount of compressive deformation Dc of the golf ball 2 is equal to or greater than 1.8. The diameter of the center 10 is equal to or less than 20 mm. The difference (He-Ho) between a surface hardness He of the core 4 and a central hardness Ho of the center 10 is equal to or less than 40.
    Type: Application
    Filed: November 4, 2011
    Publication date: June 28, 2012
    Inventors: Yoshiko Matsuyama, Takahiro Sajima, Keiji Ohama
  • GOLF BALL
    Publication number: 20120158372
    Abstract: Based on a surface shape appearing at a predetermined point moment by moment during rotation of a golf ball having numerous dimples on its surface, a data constellation regarding a parameter dependent on a surface shape of the golf ball is calculated. Preferably, the parameter is a distance between an axis of the rotation and the surface of the golf ball. Another preferable parameter is a volume of space between a surface of a phantom sphere and the surface of the golf ball. Based on a maximum value and a minimum value of the data constellation, a fluctuation range is calculated. By dividing the fluctuation range by a total volume of the dimples, an evaluation value is calculated. This value is calculated for each of PH rotation and POP rotation.
    Type: Application
    Filed: February 24, 2012
    Publication date: June 21, 2012
    Inventors: Hyoungchol KIM, Takahiro SAJIMA, Kaname YAMADA