JP2007136182A - Mold for golf ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved golf ball, capable of restricting damage to dimples in elimination of burrs after molding to reduce labor at the work, and providing such a split line form as to improve symmetric performance, increase a dimple coverage ratio, and smooth the impression of the equatorial line. <P>SOLUTION: This mold comprises an upper hemispheric half and a lower hemispheric half. The halves are engaged with each other to be detachable along a non-flat split line that is not at a corresponding position to the equatorial line of a spherical cavity. Each half of the mold is disposed in such a way that at least one dimple crosses the equatorial line. The split line passes around and between the dimples that are set to each other without crossing the dimples. A seamless golf ball is thus generated. A non-flat surface of the upper half of the die has at least three real sprues to discharge air and excess material. It also has at least three false sprues for disposing tabs on a cover, and when the ball is rotated in a buff polisher, the golf ball can be arranged in order. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates generally to an improved golf ball mold having a non-planar dividing surface for use in making "seamless" golf balls, and more particularly to a non-planar surface for use in a computerized molding system. It is related with the method of defining.

  Conventional golf ball manufacturing techniques include several different steps depending on the type of ball, eg, one piece, two piece, three piece, or more pieces of ball. According to traditional techniques, a solid or composite elastomeric core is used and an outer dimple cover is formed around the core.

  Two standard approaches for molding a cover over a core or over a core and inner layer are compression molding and injection molding. The compression molding operation is realized by using a pair of hemispherical molds having a row of protrusions provided by machining or the like in the cavity, and these protrusions form a dimple pattern around the golf ball in the cover molding operation. To do. A pair of hemispherical cover blanks are placed on the golf ball body in opposite positions, and the golf ball body is placed in a hemispherical mold with the cover blanks and then subjected to compression molding operations. . The combination of heat and pressure applied during the molding operation causes the cover blanks to fuse together and with the golf ball body to form a uniform one-piece structure that surrounds the golf ball body. Further, the cover material plate is simultaneously molded to match the inner shape of the hemispherical mold to form a dimple pattern around the golf ball cover. When machining the dimple protrusions in the mold cavity, the protrusions are typically located below the theoretical parting line of the molded cavity to be manufactured. The parting line is typically machined after the dimple formation process. For ease of manufacture, the cavity-like parting line is machined perpendicular to the flat and dimpled surface to ensure a tight shut-off so that the cover material does not leak from the mold. Due to such dimple arrangement and flat dividing lines, dimples are basically missing from a large circular locus on the golf ball. This is commonly referred to as the ball's equator, parting line or seam. For a long time, dimple pattern studies have been conducted to compensate for the aesthetics and / or flight performance resulting from such seams.

  As with all molding operations, when the golf ball is removed from the hemispherical mold after the molding operation, it involves molding flash and other possible protruding surface defects. The molding flash is located at the fusion circular joining position of the cover material plates and the dividing line of the hemispherical mold. The molded flash is thus on the “equator” of the golf ball.

  Mold flashes and other defects protruding from the possible surface must be removed, usually by one or a combination of the following: That is, a cutting blade, an abrasive belt, a grindstone, or the like. These types of work help the appearance of the seam. Alternative finishing treatments have been developed to minimize this effect. These treatments include solvent agitation, hard brush, low temperature flash removal, and the like. Regardless of the finishing treatment, flat parting lines have been formed in areas substantially free of dimple coating.

  When the flash is removed by grinding, it is preferable to realize the molding operation so that the molding flash is disposed only on the surface of the golf ball and does not extend into any dimple. In other words, the grinding operation is difficult to reach into the dimples of the golf ball to remove the molded flash without damaging the golf ball cover. Therefore, the conventional hemispherical mold is basically processed so that the dimple-forming projections formed inside thereof are retracted from the circular rim, that is, the mouth portion of the cavity. As a result, the equator of the molded golf ball has no dimples, and the molded flash is located only on the smooth surface provided on the equator of the golf ball.

  It is widely known that the dimple pattern of a golf ball is a critical element as far as the flight characteristics of the golf ball are concerned. Dimples affect the lift, drag, and flight darkness of a golf ball. When the golf ball is properly struck, the golf ball rotates about a horizontal axis and the desired lift, drag and flight stability characteristics are achieved by the interaction between the dimples and the incoming air flow.

  In order for the golf ball to consistently perform optimal flight, the dimples need to be arranged with respect to multiple axes of symmetry. Otherwise, it will fly differently depending on the direction. Most conventional golf balls include a single dimple-free equator dividing line, which naturally limits the number of axes of symmetry to one. In order to achieve consistently good flight, it is often necessary to adjust the position and / or size and / or shape of a given dimple to compensate for this constraint. Alternatively, an axis of symmetry can be added by incorporating an additional non-dimple “false” parting line. However, this practice increases the amount of non-dimple surface on the ball, which in turn reduces the flight distance of the ball.

  In order to improve performance and to provide consistency, it is preferable to use a dimple pattern that does not require adjustment or addition of a false dividing line. It is therefore preferable to remove the equator dividing line, and it is best to do so by including dimples that intersect the equator. Some US patents aimed at placing dimples on the equator of the ball are US Pat. Nos. 6,632,078 (Patent Document 1, Ogg et al.), US Pat. No. 6,200,322 (Patent Document 2, Kasashima et al.), US Pat. (Patent Literature 3, Inoue et al.), And No. 4653758 (Patent Literature 4, Solheim). These patents introduce "stepped" or "zigzag" dividing lines. This leads to the possibility of increased symmetry fit, but they were not sufficient to improve dimple coverage. This is because the dividing line includes a straight line segment and the dimples are not interlaced on both sides of the equator. The stepped path prevents many dimples from becoming interlaced and often leads to a loss of dimple coverage. US Pat. No. 6,936,208 (Patent Document 5, Ogg) describes the formation of a partial or continuous tab formed by the overlap of adjacent concave and convex tabs to reduce the size of the seam around the ball. Teaching.

Therefore, it reduces dimple damage during flash removal, improves symmetric performance, increases dimple coverage, softens the equator's visual impression, and reduces the effort and effort to remove it There is a need for a mold that produces a new and improved golf ball having a parting line shape.
U.S. Pat. No. 6,632,078 US Pat. No. 6,200,272 US Pat. No. 5,840,351 US Pat. No. 4,653,758 US Pat. No. 6,936,208

  The present invention provides a mold for forming a castable cover (for example, urethane) on a golf ball. The mold includes a hemispherical mold cup that removably engages along a non-planar parting line, ie, an upper mold cup and a lower mold cup. Both cups have internal cavity details and, when assembled, form a generally spherical cavity and provide a dimple pattern on the golf ball. The upper and lower mold cups have non-flat engagement surfaces, each surface having a plurality of peaks and valleys, formed by a computer modeling system. In the assembled state, the dividing line follows the contour pattern of the dimple, and the contour pattern of the dimple of one mold cup interpenetrates with the contour pattern of the dimple of the other mold cup. A golf ball that is substantially seamless is formed. The non-planar surface of the upper mold has at least three genuine sprues and three false sprues, and more preferably has five genuine sprues and five false sprues. Another embodiment includes a lower mold having these sprues on a non-planar surface. The false sprue has a retraction where a tab is added to the cover to align with the golf when the golf rotates in the buffing machine. The tab is then removed by knife processing.

  The invention ensures that tabs that are later removed and discarded occupy less than 15% of the non-planar surface. This can substantially reduce the amount of material disposed.

  The present invention implements a method for molding a non-flat golf ball split surface, which first generates a three-dimensional computer model representing the golf ball, and then represents it as a two-dimensional curve on a specified plane. Building a parting line profile to be performed. Second, the parting line profile is projected onto the three-dimensional surface of the golf ball model, and this profile produces an illuminated surface that includes parting lines that form the parting plane of the golf ball mold model. Finally, a non-flat split surface is manufactured on a golf ball mold using a CNC machining tool.

  The present invention uses a computerized modeling system such as CAD (Computer Aided Design) or CAE (Computer Aided Engineering) to generate a non-planar parting line profile.

  Another object of the present invention is to form a parting line profile composed of arc segments that are connected to each other and interweave the paths around and between the dimples without intersecting.

Detailed Description of the Invention

  1 to 4 show an improved mold of the present invention, which is indicated by reference numeral 30, and referring to these figures, a mold 30 having a spherical cavity 31 is used for a golf ball. Used to form a cover. Here, the mold 30 has a hemispherical mold half, ie, an upper mold half 32 and a lower mold half 33, both halves having dimple cavity details 34a, 34b, respectively, Details of upper mold half 34a are shown in FIGS. 2, 2A and 2B, which are for a castable cover on the core, in FIGS. 3 and 3A to form a cover manufactured from Surlyn. The molds are designed so that when the halves are engaged, the halves define a dimple arrangement. Arbitrary dimple arrangements, for example, icosahedron, octahedron, cube octahedral, bipyramid, etc. have a dimple pattern. Although preferred dimples are circular from the above, the dimples may be oval, triangular, quadrangular, pentagonal, hexagonal, heptagonal, octagonal, and the like. Possible cross-sectional shapes include, but are not limited to, arcs, truncated cones, flattened trapezoids, and profiles defined by parabolas, ellipses, hemispherical curves, dished curves or sine curves. Other possible dimple designs include dimples in the dimple and dimples at a constant depth. Furthermore, if necessary, a plurality of shapes or types of dimples may be used for a single ball.

  Upper and lower mold halves 32 and 33 have non-planar dividing line surfaces 35 and 36, respectively, which are stepped as best shown in FIG. There are peaks and valleys, which are generated by a definition, modeling and manufacturing method using a computerized modeling system as discussed below. When assembled, the non-flat dividing line 37 follows the dimple contour, and the dimples on one mold half are interdigitated with the dimples on the mold half on the engagement side, resulting in a substantially seamless appearance. Can be formed.

  The non-flat parting line 37 is machined to follow the profile of the equator dimple. Typically, the non-planar parting line is at least 0.001 inches away from the equator dimple when machined so that it does not collide with the perimeter of the dimple. This forms a corrugated dividing line, which has a plurality of peaks and troughs. Typically, the peak (the highest point of the dividing line) is located above the theoretical center of the cavity half, and the valley (the lowest point) is located below the theoretical center of the cavity half. Is done. The offset distance between the peak and valley is about half the diameter of the dimple, that is, about 0.001 inch. Designs incorporating offsets of the order of 0.001 inches have the advantage that the dimples are interdigitated and only cause a small amount of cutout in the cavity. Such alternating geometry is consistent throughout the dividing line plane of the mold halves 32 and 33.

  The cavity design of this invention can be applied to any golf ball molding process including injection molding, compression molding and casting. This is applicable to non-flat dividing lines used to produce “seamless” golf balls in addition to standard flat dividing lines.

  The cavity design of the present invention is incorporated into the above-described method for generating the stepped rim definition required for the non-flat parting line 37 of the golf ball. As explained below, the basics of design apply regardless of whether the ball has a Surlyn or castable cover. However, the mold has a different structure depending on the cover material.

  Many today's “seamless” molding methods define groups of dimples that traverse the theoretical midplane of a non-planar parting line. The above-described method of the present invention allows the position of each dimple to be easily and individually defined (rather than as a group of dimples) regardless of the dimple pattern, thereby defining the undulating surface of the cavity.

  The main inventive idea of this invention is shown in FIGS. 2, 2A and 2B, which includes a mold surface 35 that engages a lower mold 33 to produce a castable covered ball. The upper metal mold | die 32 which has is shown. The cavity design of the non-flat parting line of the present invention utilizes three or more drains (sprues) spaced at equal intervals and depends on the dimple pattern. As shown, FIGS. 2, 2A, and 2B show five true drains 40 and five false drains 50. FIG. The design of the fake drain 50 (FIG. 2B) is such that small portions of material (“tabs”) are intentionally molded onto the ball and remain on the ball until they are removed by a knife process. This tab is due to a land area 51 having a weir 52 and a relatively small recess 53 is filled with a cover material to form a “tab”. In addition to the fake drain 50, this cavity design incorporates five real drains 40, as shown in FIG. 2A. The real exhaust 40 provides an exhaust hole that allows trapped air and / or excess material in the material surrounding the core to flow out as much as necessary. As described above, in the preferred embodiment, only the upper mold 32 comprises the discharge sections 40 and 50, but both the mold sections 32 and 33 have the discharge sections 40 and 50 without departing from the technical scope of the present invention. Note that 50 may be included.

  3 and 3A show an upper mold 32a for molding Surlyn as a cover material. When molding the Surlyn cover, the mold does not include the fake discharge 50, but rather includes an open discharge 55, which extends across the entire molding surface 35a.

  Regardless of whether the cover material is Surlyn, and whether it is compression molded or retracted pin molded, regardless of whether it is a castable cover, such as urethane or urea, the resulting golf The ball will have a “seamless” appearance.

  Molded in the form of three elements: first, a non-planar dividing line, second, a tab left behind from the molded and implemented discharge, and third, a false discharge. The combination of tabs allows the seamless balls to be oriented to enter the buffing machine. When the golf ball is rotating at the orientation station of the buffing machine, the molded tab determines the actual buff line position. If alignment is not completed within a predetermined time, the ball will not be buffed and will be ejected as an unpolished ball, later requiring another pass through the machine. The core concept of the present invention is to create a tab that minimizes excessive flushing to be removed, thereby reducing time and material waste. The maximum amount of tab material to be removed is maintained below 15% of the surroundings. Another particular advantage of the tab produced by this invention is that it can be removed with a cutting knife, which saves time over flash buffing and grinding.

  The non-planar parting line of the mold 30 described above uses a computerized modeling system, such as CAD (Computer Aided Design), CAE (Computer Aided Engineering), or similar types of systems with CNC machining tools. This is a result of incorporating a cavity design having a stepped rim shape (non-flat dividing surface) generated in the mold. Preferably, the modeling system incorporates parametric three-dimensional solid modeling capability, which is necessary to properly manufacture or process a golf ball with a surlyn or castable cover, often referred to as a “seamless” golf ball It is said.

  Many dimple patterns incorporate repeating segments, which are used to determine the overall dimple sequence. In such cases, only the portion of the golf ball or mold that is sufficient to define the entire golf ball or mold is required.

  A so-called “seamless” golf ball can be manufactured by using a mold having a non-flat dividing surface. In this case, the dividing line on the molded product is not a large circle. Rather, the dividing line typically includes corrugations, steps, or other shapes that allow the dividing line to pass around and between the intricate dimples without intersecting the dimples. Once the parting line workpiece has been removed by buffing or other finishing process, the appearance of the ball becomes seamless.

  The method of the present invention employs six basic steps to achieve a seamless appearance. These steps are as follows:

(1) Generating a three-dimensional computer model representing a golf ball. This model can be built in many different ways, depending on the system employed and the designer's preference. It is preferably performed on the smallest golf ball portion that is sufficient to sufficiently define the dimple pattern. FIG. 5 shows an example of the golf ball partial model 100.

(2) A dividing line profile plane is constructed as a two-dimensional curve on a plane arranged for convenience. The plane 102 is preferably arranged parallel to the polar axis of the ball and separated by a distance greater than the radius of the ball. Such a plane is shown in FIG. To construct the parting line profile 104, it is convenient to use a line of sight perpendicular to the plane, as shown in FIGS. Here, the profile 104 can be constructed from arc segments, line segments, or any other type of curve component supported by the system. Typically, the profile 104 turns around and between the dimples without intersecting the dimples. It is very useful to define the profile geometry by a parameter method using reference points and constraint points based on the dimple pattern geometry. For example, the profile 104 of FIG. 8 includes arc segments constrained to be concentric with adjacent dimples, and the radius parameter is set to a specific value greater than the dimple radius. The curved segments must be continuous with one another and preferably tangentially connected when possible. In this example, it is only necessary to generate a parting line profile for half of the ball segments in the figure from the mirror symmetry of the dimple pattern.

(3) Projecting the parting line profile 104 onto the three-dimensional surface of the golf ball as shown in FIG. Projection occurs along a direction selected to properly position the dividing line of the ball and is typically orthogonal to the plane of the two-dimensional dividing line profile. In this case, two half of the dividing line is generated as a mirror image.

(4) forming the radiation surface 108 including the dividing line 37 and defining the molding dividing surface 110; As shown in FIGS. 10-11, the dividing line path is used as a profile to generate a radial geometric component 112 that defines the dividing surface of the golf ball mold. Depending on the particular system being used and the designer's preference, the geometric component can be a radial surface component 112 (as shown), a radially protruding solid component, or other types of radial components. There is. The radiant component 112 may be generated as part of a golf ball model or as part of a mold model. The origin of radiation is along the polar axis of the ball or cavity, and the direction of radiation is parallel to the equatorial plane of the ball or mold cavity.

(5) forming a split surface of the golf ball mold using the radiating surface 108; An example of an exploded view is shown in FIG. 11, in which the split operation is performed using the radiating surface 108. Radiation surface 108 scrapes waste material along the edges of the mold, leaving the desired non-planar mold parting line 110.

(6) Forming a split surface of the golf ball mold 106 using at least one result of Steps 3 to 5. The split surface of the golf ball mold is machined using the geometry generated in the above steps. This is preferably accomplished using a CNC machining tool controlled by a program generated directly from the model.

  This method makes it easy to define the non-planar surface of any cavity, whatever the dimple pattern.

  In manufacturing a golf ball, it is important to accurately engage the divided surfaces of the mold. This minimizes the amount of flash and other parting line workpieces, improves the appearance of the finished golf ball, increases uniformity, and further increases or decreases the size, weight and roundness of the golf ball. Many golf ball molds employ a flat dividing surface to achieve extremely fine engagement. However, as discussed above, the resulting large circular dividing line on the molded ball restricts the arrangement of dimples and adversely affects aerodynamic characteristics. As a result, the distance decreases, the accuracy decreases, and the performance changes depending on the direction of the golf ball. Also, for some golfers, large circle dividing lines without dimples are not attractive.

  While it will be appreciated that the exemplary embodiments of the invention described herein will satisfy preferred embodiments of the invention, it should be understood that various modifications and other embodiments can occur to those skilled in the art. Examples of such changes include slight changes in the numerical values described above. Accordingly, the numerical values recited above and in the claims include such numerical values and include values that are close to or very close to the values described above and recited in the claims. Accordingly, the claims are intended to cover all such modifications and other embodiments, and are to be understood as falling within the spirit and scope of this invention. The dimple pattern of the present invention can be employed in connection with any type of golf ball with any playing characteristics. For example, the dimple pattern can be used with a normal golf ball, i.e., solid or pincushion. These balls typically have at least one core layer and at least one cover layer. A wound ball typically winds a tensioned elastomeric thread around a spherical solid rubber or liquid filled center. However, pincushion balls typically fly a shorter distance when hit, compared to two-piece balls. Solid ball cores are generally manufactured from polybutadiene compositions. In addition to the one-piece core, the solid core may include multiple layers as in the case of a dual core golf ball. Solid or wound ball covers are generally made of ionomer resin, balata, or polyurethane, and include a single layer or multiple layers, optionally including at least one intermediate layer disposed around the core.

  All patents and patent applications described by number are incorporated herein.

  Although preferred embodiments of the present invention have been described above, it should be noted that they have been described by way of example and not limitation. It will be apparent to those skilled in the art that various changes in form and detail can be employed without departing from the spirit and scope of the invention. For example, although a preferred dimple size has been described above, other sizes of dimples can be employed. The invention is not limited to the above-described exemplary embodiments, but is defined only in accordance with the following claims and their equivalents.

It is an expansion schematic diagram which shows the discharge | emission part on an upper mold half of the metal mold | die containing both mold halves. FIG. 3 is a plan view of an upper mold half of a mold designed for a urethane cover ball. It is an enlarged view of the A section of FIG. It is an enlarged view of the B section of FIG. It is a schematic diagram of the upper mold | die explaining the discharge part designed for the balls of Surlyn cover. It is an enlarged view of the A section of FIG. It is a schematic diagram of the completed metal mold | die which shows a non-flat parting line. It is a golf ball segment based on the method for defining a dividing line of the present invention. It is a golf ball segment explaining a parting line profile construction plane. FIG. 7 is a view perpendicular to the construction plane of FIG. 6. It is a figure explaining the arc line segment restricted so that it might be concentric with the nearby dimple. It is a figure explaining projecting a two-dimensional parting line profile on the surface of a ball, and generating a three-dimensional parting line path. FIG. 10 is a diagram illustrating generation of a radial geometric component that defines a dividing surface of a golf ball mold using the dividing line path of FIG. 9. It is an enlarged view explaining how the division | segmentation surface of a shaping | molding die cavity is produced | generated using the radiation | emission component of FIG.

Explanation of symbols

30 Mold 31 Cavity 32 Upper mold half 33 Lower mold half 34a, 34b Dimple cavity details 35 Dividing line surface 37 Dividing lines 40, 50 Discharge part 52 Damping part 53 Retreat part 55 Discharge part

Claims (21)

In a mold for producing a golf ball having a non-flat dividing line,
Having hemispherical upper and lower mold halves that removably engage along a non-planar line different from the position corresponding to the equator line of the spherical cavity;
Each mold half has an internal cavity detail to form a dimple pattern on the golf ball cover, at least one dimple is disposed across the ball equator, and the dividing lines interlace with each other. Without passing the dimples around and between dimples,
Each metal half has internal cavity details, and each mold half has a non-planar split surface generated by a computerized modeling system and a CNC machining tool,
The non-planar surface of the upper mold half has at least three real exhausts for exhausting air and excess material;
The non-planar surface of the upper mold half allows at least three tabs to be added to the cover that are used to align the golf ball as it is rotated in a buffing machine. A mold characterized by having a fake discharge part.   The mold according to claim 1, wherein the cover is formed of a urethane or urea material.   The mold of claim 1, wherein the tab occupies less than 15% of the non-planar surface.   The mold of claim 1, wherein the non-planar dividing surface is at least 0.001 inches away from adjacent dimples.   5. The mold according to claim 4, wherein the non-flat dividing line includes an arc segment that is constrained to be concentric with an adjacent dimple and has a radius parameter larger than the radius of the dimple.   The mold according to claim 5, wherein the arc segments are continuous with each other.   The mold according to claim 1, wherein the tab is removed by a knife process.   2. The mold according to claim 1, wherein the dimples of the molded golf ball have an icosahedron arrangement pattern.   2. The mold according to claim 1, wherein the dimples of the molded golf ball have an octahedral arrangement pattern.   The mold according to claim 1, wherein the dimples of the molded golf ball have a cubic octahedron arrangement pattern.   The mold according to claim 1, wherein the dimples of the molded golf ball have a bipyramidal arrangement pattern.   The mold of claim 1, wherein the non-planar surface of the upper mold has five real discharge sections and five false discharge sections.   The mold of claim 1, wherein the non-planar surface of the lower mold half further comprises at least three true discharges and at least three false discharges. The mold according to claim 1.   14. A mold according to claim 13, wherein the non-planar surface of the lower mold half has five real discharge parts and five false discharge parts. The mold according to claim 1. In a method for producing a non-flat golf ball split surface,
Generating a three-dimensional computer model representing the golf ball;
Constructing a dividing line profile plane as a two-dimensional curve on the arranged plane;
Projecting a parting line profile onto a three-dimensional surface of the golf ball model to define a parting line;
Generating a radiating surface on the golf ball model including the projected dividing line profile to define a mold dividing surface;
Forming a split surface of the model of the golf ball mold using the radiation surface;
Forming the non-flat split surface of the golf ball mold.   The method of claim 15, wherein the ball has a radius and the disposed plane is parallel to the polar axis of the ball by a distance greater than the radius.   16. The method of claim 15, wherein the profile of the dividing line comprises a circular arc segment that winds around and between the dimples without describing the dimple.   18. The method of claim 17, wherein the arc segment is concentric with an adjacent dimple and has a radius parameter greater than the radius of the dimple.   The method according to claim 17, wherein the arc segments are continuous with each other.   The method of claim 15, wherein the non-planar parting line profile is constructed by a computer aided design or computer aided engineering system.   The method of claim 15, wherein the formation of the non-planar dividing surface is performed using a CNC machining tool.

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