# US 2014/0194225 A1 · Golf ball having a hollow center > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194225 A1 - Document ID: US20140194225A1 - Status: Published application - Kind: A1 - Application number: 13/737,041 - Filed: 2013-01-09 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: Acushnet Company - Applicants: Acushnet Company - Inventors: Michael J. Sullivan; Mark L. Binette; Brian Comeau - Web page: https://patentgrep.com/patent/US20140194225A1 ## CPC - A63B 37/0056: {Hollow; Gas-filled} - A63B 37/0027: {Polyurea} - A63B 37/0039: {characterised by the material} - A63B 37/0041: {Coefficient of restitution} - A63B 37/0044: {Hardness gradient} - A63B 37/0064: {Diameter} - A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers} - A63B 37/00776: {Slab hardness} - A63B 37/00922: {whereby hardness of the cover is lower than hardness of the intermediate layers} - A63B 37/0031: {Hardness} - A63B 37/0043: {Hardness} - A63B 37/006: {Physical properties} - A63B 37/008: {Diameter} - A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H) ## Abstract A golf ball includes a thermoset spherical inner core shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; a thermoset outer core layer formed about the shell layer; and an inner and outer cover layer formed about the outer core layer. The inner cover includes an ionomeric material and the outer cover layer includes a polyurea or a polyurethane having a hardness less than the inner cover layer. The hollow center has a diameter of about 0.51 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 3 to 25 Shore C to define a first hardness gradient, and the outer core layer has a second hardness gradient different from the first. ## Claims ### Claim 1 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer comprising a first thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; an outer core layer disposed about the shell layer, the outer core layer comprising a second thermoset material; an inner cover layer disposed about the outer core layer, the inner cover comprising an ionomeric material and having a first hardness; and an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a second hardness less than the first; wherein the hollow center has a diameter of about 0.51 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 3 to 25 Shore C to define a first hardness gradient, and the outer core layer has a second hardness gradient different from the first. ### Claim 2 (depends on 1) The golf ball of claim 1, wherein the shell layer has a surface hardness greater than about 55 Shore C. ### Claim 3 (depends on 1) The golf ball of claim 1, wherein the spherical inner core shell layer has a coefficient of restitution less than about 0.700 when measured at an incoming velocity of 125 ft/s. ### Claim 4 (depends on 1) The golf ball of claim 1, wherein the outer core layer has a coefficient of restitution, measured at an incoming velocity of 125 ft/s, higher than the coefficient of restitution, measured at an incoming velocity of 125 ft/s, of the inner core shell layer by 10-50%. ### Claim 5 (depends on 1) The golf ball of claim 1, wherein the second hardness gradient is about 0 Shore C. ### Claim 6 (depends on 1) The golf ball of claim 1, wherein the second hardness gradient is a negative hardness gradient of about 2 to 25 Shore C. ### Claim 7 (depends on 1) The golf ball of claim 1, wherein the second hardness gradient is a positive hardness gradient of about 3 to 10 Shore C. ### Claim 8 (depends on 1) The golf ball of claim 1, wherein the inner cover has a hardness of greater than about 60 Shore D and the outer cover layer has a hardness of less than about 60 Shore D. ### Claim 9 (depends on 1) The golf ball of claim 1, wherein the golf ball has a first volume and the hollow center has a second volume that is about 2% to 30% of the first volume. ### Claim 10 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a first thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; an outer core layer comprising a second thermoset material; a thermoplastic intermediate core layer disposed between the shell layer and the outer core layer; an inner cover layer disposed about the outer core layer, the inner cover comprising an ionomeric material and having a material hardness greater than about 60 Shore D; and an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a material hardness of less than about 60 Shore D; wherein the hollow center has a diameter of about 0.15 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 10 to 25 Shore C to define a first hardness gradient, and the thermoset outer core layer has a second hardness gradient different from the first. ### Claim 11 (depends on 10) The golf ball of claim 10, wherein the second hardness gradient is about 0 Shore C. ### Claim 12 (depends on 10) The golf ball of claim 10, wherein the second hardness gradient is a negative hardness gradient of about 2 to 25 Shore C. ### Claim 13 (depends on 10) The golf ball of claim 10, wherein the second hardness gradient is a positive hardness gradient of about 3 to 10 Shore C. ### Claim 14 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a first thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; an outer core layer comprising a second thermoset material; a thermoset intermediate core layer disposed between the shell layer and the outer core layer, the intermediate core layer comprising a third thermoset rubber composition different from the first and the second; an inner cover layer disposed about the outer core layer, the inner cover comprising an ionomeric material and having a first hardness; and an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a second hardness less than the first; wherein the hollow center has a diameter of about 0.15 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 10 to 25 Shore C to define a first hardness gradient, and at least one of the thermoset outer core layer or thermoset intermediate core layer has a hardness gradient different from the first. ### Claim 15 (depends on 14) The golf ball of claim 14, wherein the second hardness gradient is about 0 Shore C. ### Claim 16 (depends on 14) The golf ball of claim 14, wherein the second hardness gradient is a negative hardness gradient of about 2 to 25 Shore C. ### Claim 17 (depends on 14) The golf ball of claim 14, wherein the second hardness gradient is a positive hardness gradient of about 3 to 10 Shore C.