Bridgestone Corporation

Bridgestone Tire Company Limited

Jumei Harada

Takashi Yokoi

Tsutomu Matsunaga

Tetsuhiko Migita

Keiji Yamamoto

Kazuhiro Nishimura

Keisuke Ihara

Kazuhisa Nishigai

Jun Nomura

Kenji Tsukamoto

Michitoshi Sorioka

Golf balls are manufactured by supplying a golf ball - forming material into a mold defining a cavity of a predetermined surface pattern, thereby forming a golf ball having a surface pattern transferred from the mold cavity surface pattern. The mold is prepared by way of electroforming. First using an elastic non-metal profiling material, a male duplicate master is fabricated from a female standard mold having at least one accessory for assisting molding or post machining such as a parting surface and reference surface. An electroformed mold is fabricated from the male duplicate master. This electroformed mold is ready for use as the ball manufacturing mold.

Method for manufacturing a golf ball mold

Thread--wound golf balls are prepared by winding a rubber thread around a frozen core to form a core ball, immediately thereafter microwave heating the core ball to thaw the core, and forming a cover over the core ball. Microwave heating causes the frozen core to be briefly thawed without heating the thread rubber layer and without moisture condensation on the core ball surface, reducing the time taken for the core thawing step and eliminating the need for a drying step.

Preparation of thread-wound golf balls

A rotary roll extruder which performs shaping of material to be extruded such as raw rubber, or the like by ejecting the material to be extruded through a mouth piece by means of an extruding roll. This extruder comprises mouth piece moving means for moving a mouth piece in a radial direction of an extruding roll to make the mouth piece approach, or separate from, the circumferential surface of the extruding roll, mouth piece positioning means for positioning the mouth piece when the mouth piece is held apart from the extruding roll, and mouth piece stocking means for preliminarily stocking various kinds of mouth pieces. Shaping of the material to be extruded is effected when the mouth piece has been brought close to the circumferential surface of the extruding roll by the mouth piece moving means and it has been positioned by the mouth piece positioning means. However, for the exchange of the mouth piece, the mouth piece is separated from the extruding roll by the mouth piece moving means, and is exchanged with one of the mouth pieces stocked in the mouth piece stocking means. Thereafter, the new mouth piece is brought close to the circumferential surface of the extruding roll by the mouth piece moving means, and is positioned by the mouth piece positioning means. The mouth piece exchange work is executed automatically without the aid of any human labor.

Rotary roll extruder

In a rubber-like material kneading apparatus having a pair of rotors with radially outwardly extended long vanes in a chamber, each of the rotors has at least three long vanes which are arranged around a rotary shaft at equal angular intervals in such a manner that the cutting angle formed by the rear surfaces of the long vanes and the tangential lines at the outermost ends of the long vanes is larger than 40.degree., whereby the rubber-like material can be kneaded with high efficiency.

Rubber-like material kneading apparatus

A variable contour rubber extruder comprises a rotary driving roller, a main body forming therein an eccentric arc chamber with the rotary driving roller, and a movable mouth piece forming with a barrel surface of the rotary driving roller an opening of variable sectional area for extruding rubber material. The movable mouth piece comprises a center piece movable toward and away from the barrel surface of the rotary driving roller and a pair of side pieces overlapping the center piece and slidably adjustable in directions in parallel with an axis of the rotary driving roller.

Variable contour rubber extruder

A rotary roll-type rubber extruder including a roll having an outer cylindrical surface rotatively driven by driving means, a housing having a stationary concave surface spaced from and in opposition to the rotating outer cylindrical surface of said roll between a pair of sidewalls close to the outer cylindrical surface of the roll to form a define chamber with the roll, and a mouthpiece detachably secured to the housing to form a defined extruding opening with the roll at an outlet of the defined chamber. The concave surface of the housing is determined such that pressure gradients at mouthpieces are within a quadrilateral area having four corners corresponding to pressure gradients 65 and 150 kg/cm.sup.3 at a 1 mm opening mouthpiece and pressure gradients 11 and 23 kg/cm.sup.3 at a 5 mm opening mouthpiece in a graph having an ordinate in logarithm showing the pressure gradients ##EQU1## and an abscissa in logarithm showing heights mm of openings of the mouthpieces.

Rotary roll-type rubber extruder

An adjustable extrusion die assembly forming part of an extruder for an elastic material, comprises: a stationary die member having an end surface; a plurality of movable die members positioned in side-by-side relationship to one another and slidably contacted with one another, the movable die members respectively having end surfaces opposing to and spaced apart from the end surface of the stationary member, the end surfaces of the stationary and movable die members defining in combination an extrusion opening through which the elastic material is to be extruded, the movable die members being individually movable toward and away from the end surface of the stationary die member with respect to one another so as to vary the distances between the end surface of the stationary die member and the end surfaces of the movable die members; a guide member having formed therein a guide slit having the movable die members guided therein; and a plurality of link members each interconnecting two adjacent movable die members.

Adjustable extrusion die assembly

A method for casting pneumatic tires by pouring a fluidized tire-forming material into a molding cavity defined between the outer peripheral surface of a separable hard core of a mold assembly and the inner peripheral surface of an outer separable hard mold member of the mold assembly. The separable hard core is composed of at least three segments and toroidal in shape. At least one segment of the separable core is retracted in a radial direction and then moved in a direction which does not hinder retractive movement of the remaining segments and subsequently these remaining segments are retracted in the radial direction, whereby the cast tire can easily be removed from the mold assembly.

Methods of casting pneumatic tires

A method of and apparatus for casting pneumatic tires by pouring a fluidized tire-forming material into a molding cavity defined between the outer peripheral surface of a separable hard core of a mold assembly and the inner peripheral surface of an outer separable hard mold member of the mold assembly. The separable hard core is composed of at least three segments and toroidal in shape. At least one segment of the separable core guidingly is retracted in a radial direction and then moved in a direction which does not hinder retractive movement of the remaining segments and subsequently these remaining segments are retracted in the radial direction, whereby the cast tire can easily be removed from the mold assembly.

Apparatuses for casting pneumatic tires

A flexible annular core for the production of hollow toroidal rubber shells, particularly pneumatic tires, composed of a pair of bead portions, each of which is composed of beads, a reinforcing layer folded back so as to enclose the beads, and elastomer layers covering the reinforcing layer, and a flexible shell portion composed of the reinforcing layer covered with the elastomer layers and extending across the bead portions. The bead portion of said flexible annular core is composed of the reinforcing layer and the elastomer layer adhered with each other. The flexible shell portion of said core is composed of the reinforcing layer and the elastomer layer not adhered with each other.

Growing community of inventors

Yokohama, Japan

Jumei Harada