US20100273583A1 - Golf ball and die for molding the same - Google Patents
Golf ball and die for molding the same Download PDFInfo
- Publication number
- US20100273583A1 US20100273583A1 US12/830,891 US83089110A US2010273583A1 US 20100273583 A1 US20100273583 A1 US 20100273583A1 US 83089110 A US83089110 A US 83089110A US 2010273583 A1 US2010273583 A1 US 2010273583A1
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- United States
- Prior art keywords
- golf ball
- protrusion
- latitude
- die
- depression
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
- B29C37/02—Deburring or deflashing
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B37/00—Solid balls; Rigid hollow balls; Marbles
- A63B37/0003—Golf balls
- A63B37/0004—Surface depressions or protrusions
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B45/00—Apparatus or methods for manufacturing balls
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B37/00—Solid balls; Rigid hollow balls; Marbles
- A63B37/0003—Golf balls
- A63B37/0004—Surface depressions or protrusions
- A63B37/0019—Specified dimple depth
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B37/00—Solid balls; Rigid hollow balls; Marbles
- A63B37/0003—Golf balls
- A63B37/007—Characteristics of the ball as a whole
- A63B37/0072—Characteristics of the ball as a whole with a specified number of layers
- A63B37/0074—Two piece balls, i.e. cover and core
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B45/00—Apparatus or methods for manufacturing balls
- A63B45/02—Marking of balls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/42—Moulds or cores; Details thereof or accessories therefor characterised by the shape of the moulding surface, e.g. ribs or grooves
- B29C33/424—Moulding surfaces provided with means for marking or patterning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14819—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the inserts being completely encapsulated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/54—Balls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/54—Balls
- B29L2031/545—Football balls
Definitions
- the present invention relates to a golf ball and a die for molding the golf ball.
- a golf ball is usually manufactured by coating a core material thereof with a cover layer by using a die.
- This die is provided with support pins and vent pins.
- the die includes an upper die and a lower die, which are joined to each other at a parting line.
- the support pins, vent pins, and parting line produce burrs on the surface of golf ball. The burrs must be removed by grinding, because they may greatly impair the aerodynamic characteristics of golf ball.
- the dimples formed on the surface of cover layer each must have a specified depth. Therefore, the depths of dimples are measured repeatedly so that the dimples each have a specified depth while the surface of cover layer is ground.
- the depth of dimple is usually measured by using a depth micrometer or similar instruments.
- this measuring procedure has a problem that it requires very much time, because the dimple has a shape curved inward. Also, a problem arises in that unless the surface of golf ball is ground properly so that the dimples each have a specified depth, the golf ball does not fly along a desired trajectory.
- Japanese Patent Application Publication No. 63-99884 describes a method comprising forming two kinds of depressions having different depths on the surface of golf ball, and then grinding the surface of golf ball until the depressions having a shallower depth disappear. According to this method, a proper grinding quantity can be determined merely by visually observing the depressions.
- Japanese Patent Application Publication No. 2003-111868 describes a method comprising forming a depression having three different depths on the surface of golf ball, and then grinding the surface of golf ball. According to this method, the grinding quantity can be readily determined by visually observing the depression, because the number of the steps in the depression which are produced by different depths is changed depending on the grinding quantity.
- an object of the present invention is to provide a golf ball in which the depths of dimples after grinding, which greatly affect the trajectory of golf ball, can be controlled readily and exactly, and a golf ball molding die for manufacturing the golf ball.
- a first aspect of the present invention provides a die for molding a golf ball, comprising two die bodies in which a cavity for molding a golf ball is formed by joining the die bodies to each other; and a protrusion formed on the cavity side surface of at least one of the die bodies, the protrusion having a uniform height from the surface or an imaginary spherical surface on which the protrusion is assumed to be absent toward the center of the cavity, wherein when a parting line is at latitude zero degree, the protrusion is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
- At least one protrusion may be formed on the surface of each of the two die bodies.
- Two or more protrusions may be formed on the surface of at least one of the two die bodies.
- the two or more protrusions may be formed at equal spaces at the same latitude.
- the protrusion may be arranged in the range of from latitude about 30 degrees to latitude about 60 degrees.
- the protrusion can be high enough that the depression formed on the surface of golf ball by the protrusion does not disappear by properly grinding the surface of golf ball.
- the height of the protrusion can be in the range of from about 5 ⁇ m to about 0.1 mm.
- the protrusion can have a shape of a letter or sign.
- a second aspect of the present invention provides a golf ball manufactured by the die described below.
- This golf ball molding die comprises two die bodies in which a cavity for molding a golf ball is formed by joining the die bodies to each other; and a protrusion formed on the cavity side surface of at least one of the die bodies, the protrusion having a uniform height from the surface or an imaginary spherical surface on which the protrusion is assumed to be absent toward the center of the cavity, wherein when a parting line is at latitude zero degree, the protrusion is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
- a third aspect of the present invention provides a golf ball comprising dimples formed on the surface of the golf ball; and a depression formed on the surface of the golf ball, the depression having a uniform depth from the surface of the golf ball or an imaginary spherical surface on which the depression is assumed to be absent toward the center of the golf ball, wherein when a parting line of the golf ball is at latitude zero degree, the depression is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
- the poor workability of measurement of grinding quantity can be improved, and also the grinding quantity can be measured exactly.
- the depths of dimples can be calculated from the grinding quantity with high accuracy, so that the depths of dimples after grinding, which greatly affect the trajectory of golf ball, can be controlled readily and exactly. Therefore, according to the present invention, a golf ball that flies along a proper trajectory can be manufactured stably and easily.
- FIG. 1 is a sectional view of a golf ball molding die in accordance with one embodiment of the present invention
- FIG. 2 is a schematic view of a cavity in the die shown in FIG. 1 ;
- FIG. 3 is a perspective view of a golf ball in accordance with one embodiment of the present invention.
- FIG. 4 is an enlarged perspective view showing one example of a depression on the golf ball shown in FIG. 3 ;
- FIG. 5 is an enlarged perspective view showing another example of a depression on the golf ball shown in FIG. 3 ;
- FIG. 6 is an enlarged perspective view showing still another example of a depression on the golf ball shown in FIG. 3 ;
- an injection molding die 1 is used.
- This injection molding die 1 includes an upper die 2 and a lower die 3 , which are made of a metal. By separably joining the upper die 2 and the lower die 3 to each other, a spherical cavity 4 is formed in the die 1 .
- a parting line PL of the upper die 2 and the lower die 3 is located at a position corresponding to the equator, that is, latitude zero degree of the cavity.
- a large number of convex parts (not shown) are provided to form dimples on the surface of the cover layer.
- a protrusion (not shown) is provided to form a depression on the surface of golf ball, which is used to measure the grinding quantity when the surface of golf ball is ground. This protrusion is explained in more detail with reference to FIG. 2 . In FIG. 2 , which is not drawn to scale, the protrusion is drawn enlargedly with respect to the cavity for easily explaining the configuration of protrusion.
- a protrusion 21 is formed on the cavity wall surface 7 of the die 1 .
- This protrusion 21 is formed so as to have a uniform height toward the center C of the cavity 4 from the cavity wall surface 7 or an imaginary spherical surface indicated by a broken line.
- the uniform height of the protrusion 21 produces a uniform depth of a depression formed on the surface of golf ball. Therefore, the grinding quantity can be measured readily and exactly by using a depth micrometer or similar instruments.
- the protrusion 21 has a height such that the depression formed in the surface of golf ball by the protrusion does not disappear when the surface of golf ball is ground properly.
- the lower limit of the height of the protrusion 21 is preferably about 5 ⁇ m, further preferably about 10 ⁇ m.
- the upper limit of the height of the protrusion 21 is preferably about 0.1 mm, further preferably about 30 ⁇ m. A height of the protrusion 21 exceeding about 0.1 mm is unpreferable because an excessively deep depression is formed on the surface of golf ball, and thereby an adverse influence may be exerted on the trajectory of golf ball.
- the position at which the protrusion 21 is arranged can be represented by latitude ⁇ .
- the latitude ⁇ is represented with the parting line PL, at which the upper die 2 and the lower die 3 of the die 1 are joined to each other, being latitude zero degree.
- the latitude ⁇ is represented by a positive value for both of the upper die 2 and the lower die 3 .
- the protrusion 21 is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees. By arranging the protrusion 21 in this range, the influence of burrs formed by pins near the North Pole and South Pole or burrs formed by the parting line at the equator is avoided, by which a depression having a desired depth can be formed in the surface of golf ball accurately.
- the protrusion 21 is preferably formed at a position of latitude about 30 degrees or higher. Also, the protrusion 21 is preferably formed at a position of latitude about 60 degrees or lower.
- FIG. 2 illustrates the protrusion 21 formed only on the upper die 2 .
- the protrusion 21 can also be formed on the lower die 3 in the same manner.
- FIG. 2 illustrates only one protrusion 21 .
- two or more protrusions can be formed on the upper die 2 or the lower die 3 .
- a plurality of protrusions 21 are preferably formed at positions of the same latitude ⁇ .
- a plurality of depressions are formed at positions of the same latitude of golf ball, so that the grinding quantity can be measured exactly.
- the protrusions 21 are preferably formed at equal spaces at the same latitude ⁇ .
- the plurality of depressions are formed at equal spaces at the same latitude, so that the grinding quantity can be measured exactly over the whole surface of golf ball, and also the grinding error can be reduced.
- the shape of the flat part at the tip end of the protrusion 21 can be, but is not limited to, slender so that the depth of the depression formed in the surface of golf ball can be measured easily.
- the shape of the protrusion 21 can be made a shape of a letter or sign.
- the shape of the protrusion 21 is preferably a shape of a letter or sign having symmetry such as line symmetry or point symmetry. By the provision of symmetry, the grinding quantity can be measured exactly, and also the grinding error can be reduced.
- a gas vent pin 5 for venting gas is provided at the North Pole point and the South Pole point, that is, at positions of latitude 90 degrees of the cavity 4 .
- a plurality of support pins 6 for supporting a core material 11 are provided at positions such as to be capable of stably supporting the core material 11 of golf ball so as to be capable of advancing and retreating.
- a ring-shaped runner 8 is provided so as to surround the equator of the cavity 4 .
- a plurality of molding material injection gates 9 that are open to the interior of the cavity 4 are provided at equal spaces along the circumferential direction in an inner peripheral part of the ring-shaped runner 8 .
- Such a die can be manufactured by using a method for directly cutting out three-dimensionally or by the electrical discharge machining by using 3DCAD or CAM.
- the core material 11 of golf ball is placed between the upper die 2 and the lower die 3 , and the upper die 2 and the lower die 3 are joined to each other to form the cavity 4 .
- the core material 11 is supported at the central part by the support pins 6 , and then a cover material whose main component is a thermoplastic resin is injected into the cavity 4 through the molding material injection gates 9 .
- the cover material flows in a void part between the core material 11 and the cavity wall surface 7 , and joins at the North Pole point and the South Pole point of the cavity 4 , by which the whole surface of the core material 11 is coated with the cover material.
- Air that is present in the clearance between the core material 11 and the cavity wall surface 7 and a gas such as a volatile component released mixedly with a resin are discharged to the outside of the die 1 via the gas vent pin 5 .
- the rubber-made elastic body which is the core material 11
- the cover layer by which a golf ball formed with a plurality of dimples on the surface of the cover layer is manufactured.
- FIG. 3 shows one example of a golf ball molded as described above.
- a plurality of dimples 12 are formed on the surface of a golf ball 10 formed with the cover layer on the core material.
- each of the dimples 12 has a shape that is circular in plan view and depressed so as to be curved to the center side.
- the shape of the dimple 12 is not limited to this shape.
- the dimple 12 can have an elliptical shape or polygonal shape in plan view, or can have a shape such as to be curved in two stages to the center side.
- depressions 14 for measuring the grinding quantity are formed at positions between the dimples 12 .
- the depression 14 is formed by the protrusion 21 of the die 1 .
- the depression 14 has a fixed depth from the surface of golf ball or the imaginary spherical surface drawn assuming that the depression is absent toward the center of golf ball.
- the lower limit of the depth of the depression 14 is preferably about 5 ⁇ m, further preferably about 10 ⁇ m.
- the upper limit of the depth of the depression 14 is preferably about 0.1 mm, further preferably about 30 ⁇ m.
- the depressions are located in the range of from latitude about 10 degrees to latitude about 80 degrees.
- the preferable range is from latitude about 30 degrees to latitude about 60 degrees.
- the parting line of golf ball is usually straight along the equator of golf ball. In this case, usually, the dimples are not formed on the parting line. Therefore, the parting line can be found from the appearance of golf ball.
- the present invention can be applied to a golf ball in which the parting line has a waveform shape along the equator of golf ball. In this case, the positions corresponding to the North Pole and the South Pole of die are made latitude 90 degrees, and with these positions being a reference, the position of latitude zero degree is made a parting line.
- FIGS. 4 to 6 show specific examples of the depression 14 formed on the surface of the golf ball 10 .
- a depression 14 A having a T shape is formed.
- an O-shaped or round sign shaped depression 14 B is formed.
- I-shaped or minus sign shaped depression 14 C is formed.
- the shape of the depression 14 is not limited to these shapes, and a shape such as a shape of letter such as H or a shape of any other sign can be adopted.
- the whole surface of the golf ball 10 is ground.
- the conventional grinding method can be used.
- the grinding quantity can be calculated from the depth at the start of formation of depression by measuring the depth of the depression 14 by using a depth micrometer etc. Since the depth of the depression 14 is fixed at all locations of the depression 14 as described above, the grinding quantity can be measured easily and exactly. Also, since the depth of the depression 14 is formed accurately, the grinding quantity can be calculated with high accuracy by measuring the depth of depression.
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- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
There are provided a golf ball in which the depths of dimples after grinding, which greatly affect the trajectory of golf ball, can be controlled readily and exactly, and a golf ball molding die for manufacturing the golf ball. The golf ball molding die in accordance with the present invention comprises two die bodies in which a cavity for molding a golf ball is formed by joining the die bodies to each other; and a protrusion formed on the cavity side surface of at least one of the die bodies, the protrusion having a uniform height from the surface or an imaginary spherical surface on which the protrusion is assumed to be absent toward the center of the cavity, wherein when a parting line is at latitude zero degree, the protrusion is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
Description
- This is a divisional of application Ser. No. 11/960,132 filed Dec. 19, 2007. The entire disclosure of the prior application, application Ser. No. 11/960,132 is hereby incorporated by reference.
- The present invention relates to a golf ball and a die for molding the golf ball.
- A golf ball is usually manufactured by coating a core material thereof with a cover layer by using a die. This die is provided with support pins and vent pins. Also, the die includes an upper die and a lower die, which are joined to each other at a parting line. The support pins, vent pins, and parting line produce burrs on the surface of golf ball. The burrs must be removed by grinding, because they may greatly impair the aerodynamic characteristics of golf ball.
- If the surface of golf ball, i.e., the surface of cover layer is ground for removing burrs, the dimples formed on the surface of cover layer each must have a specified depth. Therefore, the depths of dimples are measured repeatedly so that the dimples each have a specified depth while the surface of cover layer is ground.
- The depth of dimple is usually measured by using a depth micrometer or similar instruments. However, this measuring procedure has a problem that it requires very much time, because the dimple has a shape curved inward. Also, a problem arises in that unless the surface of golf ball is ground properly so that the dimples each have a specified depth, the golf ball does not fly along a desired trajectory.
- Japanese Patent Application Publication No. 63-99884 describes a method comprising forming two kinds of depressions having different depths on the surface of golf ball, and then grinding the surface of golf ball until the depressions having a shallower depth disappear. According to this method, a proper grinding quantity can be determined merely by visually observing the depressions.
- Japanese Patent Application Publication No. 2003-111868 describes a method comprising forming a depression having three different depths on the surface of golf ball, and then grinding the surface of golf ball. According to this method, the grinding quantity can be readily determined by visually observing the depression, because the number of the steps in the depression which are produced by different depths is changed depending on the grinding quantity.
- However, these technique described in the above-mentioned documents may impair the aerodynamic characteristics of golf ball, because deep depressions should be formed on the surface of golf ball. Also, an exact grinding quantity cannot be readily measured by these methods described in the above-mentioned documents, though a rough grinding quantity can be determined by them. Therefore, the exact depth of dimple after grinding cannot be readily measured or controlled by these techniques.
- Accordingly, an object of the present invention is to provide a golf ball in which the depths of dimples after grinding, which greatly affect the trajectory of golf ball, can be controlled readily and exactly, and a golf ball molding die for manufacturing the golf ball.
- To achieve the above object, a first aspect of the present invention provides a die for molding a golf ball, comprising two die bodies in which a cavity for molding a golf ball is formed by joining the die bodies to each other; and a protrusion formed on the cavity side surface of at least one of the die bodies, the protrusion having a uniform height from the surface or an imaginary spherical surface on which the protrusion is assumed to be absent toward the center of the cavity, wherein when a parting line is at latitude zero degree, the protrusion is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
- At least one protrusion may be formed on the surface of each of the two die bodies. Two or more protrusions may be formed on the surface of at least one of the two die bodies. The two or more protrusions may be formed at equal spaces at the same latitude. The protrusion may be arranged in the range of from latitude about 30 degrees to latitude about 60 degrees.
- The protrusion can be high enough that the depression formed on the surface of golf ball by the protrusion does not disappear by properly grinding the surface of golf ball. The height of the protrusion can be in the range of from about 5 μm to about 0.1 mm. The protrusion can have a shape of a letter or sign.
- A second aspect of the present invention provides a golf ball manufactured by the die described below. This golf ball molding die comprises two die bodies in which a cavity for molding a golf ball is formed by joining the die bodies to each other; and a protrusion formed on the cavity side surface of at least one of the die bodies, the protrusion having a uniform height from the surface or an imaginary spherical surface on which the protrusion is assumed to be absent toward the center of the cavity, wherein when a parting line is at latitude zero degree, the protrusion is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
- A third aspect of the present invention provides a golf ball comprising dimples formed on the surface of the golf ball; and a depression formed on the surface of the golf ball, the depression having a uniform depth from the surface of the golf ball or an imaginary spherical surface on which the depression is assumed to be absent toward the center of the golf ball, wherein when a parting line of the golf ball is at latitude zero degree, the depression is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
- According to the present invention, in grinding the surface of golf ball, the poor workability of measurement of grinding quantity can be improved, and also the grinding quantity can be measured exactly. Further, the depths of dimples can be calculated from the grinding quantity with high accuracy, so that the depths of dimples after grinding, which greatly affect the trajectory of golf ball, can be controlled readily and exactly. Therefore, according to the present invention, a golf ball that flies along a proper trajectory can be manufactured stably and easily.
-
FIG. 1 is a sectional view of a golf ball molding die in accordance with one embodiment of the present invention; -
FIG. 2 is a schematic view of a cavity in the die shown inFIG. 1 ; -
FIG. 3 is a perspective view of a golf ball in accordance with one embodiment of the present invention; -
FIG. 4 is an enlarged perspective view showing one example of a depression on the golf ball shown inFIG. 3 ; -
FIG. 5 is an enlarged perspective view showing another example of a depression on the golf ball shown inFIG. 3 ; and -
FIG. 6 is an enlarged perspective view showing still another example of a depression on the golf ball shown inFIG. 3 ; - One embodiment of the present invention will now be described with reference to the accompanying drawings. As a specific example, a case is explained in which a two-piece solid golf ball is manufactured by molding a cover layer around a rubber-made elastic body, which is a core material, by injection molding. The present invention is not limited to this embodiment, and can be applied to other types of gall balls.
- As shown in
FIG. 1 , when the golf ball is manufactured by the injection molding, aninjection molding die 1 is used. This injection molding die 1 includes anupper die 2 and alower die 3, which are made of a metal. By separably joining theupper die 2 and thelower die 3 to each other, aspherical cavity 4 is formed in the die 1. - A parting line PL of the
upper die 2 and thelower die 3 is located at a position corresponding to the equator, that is, latitude zero degree of the cavity. On thecavity wall surface 7 of themolding die 1, a large number of convex parts (not shown) are provided to form dimples on the surface of the cover layer. Also, on thecavity wall surface 7, a protrusion (not shown) is provided to form a depression on the surface of golf ball, which is used to measure the grinding quantity when the surface of golf ball is ground. This protrusion is explained in more detail with reference toFIG. 2 . InFIG. 2 , which is not drawn to scale, the protrusion is drawn enlargedly with respect to the cavity for easily explaining the configuration of protrusion. - As shown in
FIG. 2 , aprotrusion 21 is formed on thecavity wall surface 7 of thedie 1. Thisprotrusion 21 is formed so as to have a uniform height toward the center C of thecavity 4 from thecavity wall surface 7 or an imaginary spherical surface indicated by a broken line. The uniform height of theprotrusion 21 produces a uniform depth of a depression formed on the surface of golf ball. Therefore, the grinding quantity can be measured readily and exactly by using a depth micrometer or similar instruments. - The
protrusion 21 has a height such that the depression formed in the surface of golf ball by the protrusion does not disappear when the surface of golf ball is ground properly. Specifically, the lower limit of the height of theprotrusion 21 is preferably about 5 μm, further preferably about 10 μm. Also, the upper limit of the height of theprotrusion 21 is preferably about 0.1 mm, further preferably about 30 μm. A height of theprotrusion 21 exceeding about 0.1 mm is unpreferable because an excessively deep depression is formed on the surface of golf ball, and thereby an adverse influence may be exerted on the trajectory of golf ball. - The position at which the
protrusion 21 is arranged can be represented by latitude α. In this specification, the latitude α is represented with the parting line PL, at which theupper die 2 and thelower die 3 of thedie 1 are joined to each other, being latitude zero degree. Also, the latitude α is represented by a positive value for both of theupper die 2 and thelower die 3. Theprotrusion 21 is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees. By arranging theprotrusion 21 in this range, the influence of burrs formed by pins near the North Pole and South Pole or burrs formed by the parting line at the equator is avoided, by which a depression having a desired depth can be formed in the surface of golf ball accurately. Therefore, the grinding quantity can be measured exactly, and the depths of dimples can be controlled exactly. Theprotrusion 21 is preferably formed at a position of latitude about 30 degrees or higher. Also, theprotrusion 21 is preferably formed at a position of latitude about 60 degrees or lower. -
FIG. 2 illustrates theprotrusion 21 formed only on theupper die 2. However, theprotrusion 21 can also be formed on thelower die 3 in the same manner. Also,FIG. 2 illustrates only oneprotrusion 21. However, two or more protrusions can be formed on theupper die 2 or thelower die 3. In this case, a plurality ofprotrusions 21 are preferably formed at positions of the same latitude α. Thereby, a plurality of depressions are formed at positions of the same latitude of golf ball, so that the grinding quantity can be measured exactly. Also, theprotrusions 21 are preferably formed at equal spaces at the same latitude α. Thereby, the plurality of depressions are formed at equal spaces at the same latitude, so that the grinding quantity can be measured exactly over the whole surface of golf ball, and also the grinding error can be reduced. - Preferably, the shape of the flat part at the tip end of the
protrusion 21 can be, but is not limited to, slender so that the depth of the depression formed in the surface of golf ball can be measured easily. For example, the shape of theprotrusion 21 can be made a shape of a letter or sign. Also, the shape of theprotrusion 21 is preferably a shape of a letter or sign having symmetry such as line symmetry or point symmetry. By the provision of symmetry, the grinding quantity can be measured exactly, and also the grinding error can be reduced. - In the
cavity wall surface 7, agas vent pin 5 for venting gas is provided at the North Pole point and the South Pole point, that is, at positions of latitude 90 degrees of thecavity 4. Also, in thecavity wall surface 7, a plurality of support pins 6 for supporting acore material 11 are provided at positions such as to be capable of stably supporting thecore material 11 of golf ball so as to be capable of advancing and retreating. - In the
die 1, a ring-shapedrunner 8 is provided so as to surround the equator of thecavity 4. A plurality of molding material injection gates 9 that are open to the interior of thecavity 4 are provided at equal spaces along the circumferential direction in an inner peripheral part of the ring-shapedrunner 8. Such a die can be manufactured by using a method for directly cutting out three-dimensionally or by the electrical discharge machining by using 3DCAD or CAM. - According to the configuration of the
die 1 explained above, first, as shown inFIG. 1 , thecore material 11 of golf ball is placed between theupper die 2 and thelower die 3, and theupper die 2 and thelower die 3 are joined to each other to form thecavity 4. Thecore material 11 is supported at the central part by the support pins 6, and then a cover material whose main component is a thermoplastic resin is injected into thecavity 4 through the molding material injection gates 9. The cover material flows in a void part between thecore material 11 and thecavity wall surface 7, and joins at the North Pole point and the South Pole point of thecavity 4, by which the whole surface of thecore material 11 is coated with the cover material. - Air that is present in the clearance between the
core material 11 and thecavity wall surface 7 and a gas such as a volatile component released mixedly with a resin are discharged to the outside of thedie 1 via thegas vent pin 5. By the above-described process, the rubber-made elastic body, which is thecore material 11, is covered with the cover layer, by which a golf ball formed with a plurality of dimples on the surface of the cover layer is manufactured. -
FIG. 3 shows one example of a golf ball molded as described above. On the surface of agolf ball 10 formed with the cover layer on the core material, a plurality ofdimples 12 are formed. As shown inFIG. 3 , each of thedimples 12 has a shape that is circular in plan view and depressed so as to be curved to the center side. However, the shape of thedimple 12 is not limited to this shape. Thedimple 12 can have an elliptical shape or polygonal shape in plan view, or can have a shape such as to be curved in two stages to the center side. - On the surface of the
golf ball 10,depressions 14 for measuring the grinding quantity are formed at positions between thedimples 12. Thedepression 14 is formed by theprotrusion 21 of thedie 1. Thedepression 14 has a fixed depth from the surface of golf ball or the imaginary spherical surface drawn assuming that the depression is absent toward the center of golf ball. For example, the lower limit of the depth of thedepression 14 is preferably about 5 μm, further preferably about 10 μm. The upper limit of the depth of thedepression 14 is preferably about 0.1 mm, further preferably about 30 μm. Also, when the parting line of thegolf ball 10 is assumed to be at latitude zero degree, the depressions are located in the range of from latitude about 10 degrees to latitude about 80 degrees. The preferable range is from latitude about 30 degrees to latitude about 60 degrees. - The parting line of golf ball is usually straight along the equator of golf ball. In this case, usually, the dimples are not formed on the parting line. Therefore, the parting line can be found from the appearance of golf ball. The present invention can be applied to a golf ball in which the parting line has a waveform shape along the equator of golf ball. In this case, the positions corresponding to the North Pole and the South Pole of die are made latitude 90 degrees, and with these positions being a reference, the position of latitude zero degree is made a parting line.
-
FIGS. 4 to 6 show specific examples of thedepression 14 formed on the surface of thegolf ball 10. InFIG. 4 , adepression 14A having a T shape is formed. InFIG. 5 , an O-shaped or round sign shapeddepression 14B is formed. InFIG. 6 , I-shaped or minus sign shapeddepression 14C is formed. The shape of thedepression 14 is not limited to these shapes, and a shape such as a shape of letter such as H or a shape of any other sign can be adopted. - To remove burrs etc. formed on the surface of golf ball, the whole surface of the
golf ball 10 is ground. As the grinding method, the conventional grinding method can be used. The grinding quantity can be calculated from the depth at the start of formation of depression by measuring the depth of thedepression 14 by using a depth micrometer etc. Since the depth of thedepression 14 is fixed at all locations of thedepression 14 as described above, the grinding quantity can be measured easily and exactly. Also, since the depth of thedepression 14 is formed accurately, the grinding quantity can be calculated with high accuracy by measuring the depth of depression. - The above is an explanation of a specific embodiment of the golf ball molding die in accordance with the present invention and the golf ball manufactured by the die. The present invention is not limited to the above-described embodiment, and all changes and modifications apparent to those skilled in the art are embraced in the technical scope of the present invention.
Claims (8)
1. A golf ball manufactured by using a die, the die comprising:
two die bodies in which a cavity for molding a golf ball is formed by joining the die bodies to each other;
a protrusion formed on the cavity side surface of at least one of the die bodies, the protrusion having a uniform height from the surface or an imaginary spherical surface on which the protrusion is assumed to be absent toward the center of the cavity; and
a plurality of dimple forming projections, wherein the protrusion is formed at a position between the plurality of dimple forming projections in order to form a depression which is used for measuring the grinding quantity of a surface of the golf ball, and
wherein when a parting line is at latitude zero degree, the protrusion is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
2. The golf ball according to claim 1 , wherein at least one protrusion is formed on the surface of each of the two die bodies.
3. The golf ball according to claim 1 , wherein two or more protrusions are formed on the surface of at least one of the two die bodies, and the two or more protrusions are formed at equal spaces at the same latitude.
4. The golf ball according to claim 1 , wherein the protrusion is arranged in the range of from latitude about 30 degrees to latitude about 60 degrees.
5. The golf ball according to claim 1 , wherein the protrusion is high enough that a depression formed on the surface of golf ball by the protrusion does not disappear by properly grinding the surface of golf ball.
6. The golf ball according to claim 5 , wherein the protrusion has a height range from about 5 μm to about 30 μm.
7. The golf ball according to claim 1 , wherein the protrusion has a shape of a letter or sign.
8. A golf ball comprising:
a plurality of dimples formed on the surface of the golf ball; and
a depression used for measuring the grinding quantity of a surface of the golf ball, the depression being formed on the surface of the golf ball, being positioned between the plurality of dimples, and having a uniform depth from the surface of the golf ball or an imaginary spherical surface on which the depression is assumed to be absent toward the center of the golf ball,
wherein when a parting line of the golf ball is at latitude zero degree, the depression is arranged in the range of from latitude about 10 degrees to latitude about 80 degrees.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/830,891 US20100273583A1 (en) | 2007-12-19 | 2010-07-06 | Golf ball and die for molding the same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/960,132 US7780887B2 (en) | 2007-12-19 | 2007-12-19 | Golf ball and die for molding the same |
US12/830,891 US20100273583A1 (en) | 2007-12-19 | 2010-07-06 | Golf ball and die for molding the same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/960,132 Division US7780887B2 (en) | 2007-12-19 | 2007-12-19 | Golf ball and die for molding the same |
Publications (1)
Publication Number | Publication Date |
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US20100273583A1 true US20100273583A1 (en) | 2010-10-28 |
Family
ID=40787647
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/960,132 Expired - Fee Related US7780887B2 (en) | 2007-12-19 | 2007-12-19 | Golf ball and die for molding the same |
US12/830,891 Abandoned US20100273583A1 (en) | 2007-12-19 | 2010-07-06 | Golf ball and die for molding the same |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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US11/960,132 Expired - Fee Related US7780887B2 (en) | 2007-12-19 | 2007-12-19 | Golf ball and die for molding the same |
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US (2) | US7780887B2 (en) |
JP (1) | JP2009148563A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7803070B2 (en) * | 2006-03-30 | 2010-09-28 | Bridgestone Sports Co., Ltd. | Golf ball and golf ball mold |
JP6351933B2 (en) * | 2013-06-13 | 2018-07-04 | キヤノンメディカルシステムズ株式会社 | Magnetic resonance imaging system |
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US5566943A (en) * | 1995-01-03 | 1996-10-22 | Acushnet Company | Golf ball |
US5874038A (en) * | 1996-11-01 | 1999-02-23 | Bridgestone Sports Co., Ltd. | Injection mold for golf balls and method for preparing golf balls |
US6050803A (en) * | 1996-12-19 | 2000-04-18 | Bridgestone Sports Co., Ltd. | Golf ball mold |
US6238194B1 (en) * | 1997-12-03 | 2001-05-29 | Bridgestone Sports Co., Ltd. | Golf ball injection molds |
US6379138B1 (en) * | 2000-11-08 | 2002-04-30 | Acushnet Company | Injection molding apparatus |
US20030054902A1 (en) * | 1999-03-05 | 2003-03-20 | Yutaka Masutani | Golf ball mold and golf ball |
US20060082020A1 (en) * | 2001-12-04 | 2006-04-20 | Veilleux Thomas A | Method and Apparatus for Forming a Golf Ball |
US20060281583A1 (en) * | 2005-06-09 | 2006-12-14 | Bridgestone Sports Co., Ltd. | Golf ball |
US20070026971A1 (en) * | 2005-07-28 | 2007-02-01 | Steven Aoyama | Golf ball dimples forming indicia |
US7367905B2 (en) * | 2006-01-17 | 2008-05-06 | Bridgestone Sports Co., Ltd. | Golf ball |
US7481724B2 (en) * | 2002-05-23 | 2009-01-27 | Acushnet Company | Golf ball dimples |
US7625303B2 (en) * | 2005-04-08 | 2009-12-01 | Callaway Golf Company | Dimples composed of letters or symbols inset into cover |
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JPS6399884A (en) | 1986-10-17 | 1988-05-02 | 株式会社ブリヂストン | Production of golf ball |
JPH1189966A (en) * | 1997-09-22 | 1999-04-06 | Bridgestone Sports Co Ltd | Golf ball |
JP3468154B2 (en) * | 1999-03-24 | 2003-11-17 | ブリヂストンスポーツ株式会社 | Mold for golf ball and golf ball |
JP2003111868A (en) | 2001-10-03 | 2003-04-15 | Yokohama Rubber Co Ltd:The | Golf ball molded body and mold thereof |
JP4330958B2 (en) * | 2003-08-29 | 2009-09-16 | Sriスポーツ株式会社 | Golf ball manufacturing method |
US7354358B2 (en) * | 2005-07-15 | 2008-04-08 | Bridgestone Sports Co., Ltd. | Golf ball |
US7803070B2 (en) * | 2006-03-30 | 2010-09-28 | Bridgestone Sports Co., Ltd. | Golf ball and golf ball mold |
-
2007
- 2007-12-19 US US11/960,132 patent/US7780887B2/en not_active Expired - Fee Related
-
2008
- 2008-12-19 JP JP2008323465A patent/JP2009148563A/en active Pending
-
2010
- 2010-07-06 US US12/830,891 patent/US20100273583A1/en not_active Abandoned
Patent Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5566943A (en) * | 1995-01-03 | 1996-10-22 | Acushnet Company | Golf ball |
US5874038A (en) * | 1996-11-01 | 1999-02-23 | Bridgestone Sports Co., Ltd. | Injection mold for golf balls and method for preparing golf balls |
US6050803A (en) * | 1996-12-19 | 2000-04-18 | Bridgestone Sports Co., Ltd. | Golf ball mold |
US6238194B1 (en) * | 1997-12-03 | 2001-05-29 | Bridgestone Sports Co., Ltd. | Golf ball injection molds |
US20030054902A1 (en) * | 1999-03-05 | 2003-03-20 | Yutaka Masutani | Golf ball mold and golf ball |
US6379138B1 (en) * | 2000-11-08 | 2002-04-30 | Acushnet Company | Injection molding apparatus |
US20060082020A1 (en) * | 2001-12-04 | 2006-04-20 | Veilleux Thomas A | Method and Apparatus for Forming a Golf Ball |
US7481724B2 (en) * | 2002-05-23 | 2009-01-27 | Acushnet Company | Golf ball dimples |
US7625303B2 (en) * | 2005-04-08 | 2009-12-01 | Callaway Golf Company | Dimples composed of letters or symbols inset into cover |
US20060281583A1 (en) * | 2005-06-09 | 2006-12-14 | Bridgestone Sports Co., Ltd. | Golf ball |
US20070026971A1 (en) * | 2005-07-28 | 2007-02-01 | Steven Aoyama | Golf ball dimples forming indicia |
US7303492B2 (en) * | 2005-07-28 | 2007-12-04 | Acushnet Company | Golf ball dimples forming indicia |
US7367905B2 (en) * | 2006-01-17 | 2008-05-06 | Bridgestone Sports Co., Ltd. | Golf ball |
Also Published As
Publication number | Publication date |
---|---|
US20090160088A1 (en) | 2009-06-25 |
JP2009148563A (en) | 2009-07-09 |
US7780887B2 (en) | 2010-08-24 |
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