Preparation of thread-wound golf balls

• US 5,194,191 A
• Filed: 05/31/1991
• Issued: 03/16/1993
• Est. Priority Date: 06/01/1990
• Status: Expired due to Fees

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: Nomura, Jun, Harada, Jumei
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): EASTLEY, BRIAN
• Application Number:
  US07/707,864
• Time in Patent Office: 655 Days
• Field of Search: 264/25, 264/26, 264/28, 264/234, 264/239, 273/216, 273/227, 273/231, 273/235 A, 273/235 B
• US Class Current: 264/489
• CPC Class Codes: B29C 2033/525 Cores made of frozen liquids, e.g. ice
• CPC Class Codes: B29C 2035/0855 using microwave
• CPC Class Codes: B29C 33/52 soluble or fusible in particular used in injection moulding B29C45/4457
• CPC Class Codes: B29C 35/08 by wave energy or particle radiation B29C64/00, B29C71/04 take precedence
• CPC Class Codes: B29C 53/58 helically
• CPC Class Codes: B29D 22/04 Spherical articles, e.g. balls B29D22/02 takes precedence
• CPC Class Codes: B29L 2031/54 Balls

Abstract

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.

Claims

1. A method for preparing a thread-wound golf ball, comprising the steps of:

continuously winding a length of rubber thread around a frozen core to form a core ball;

immediately after formation of the core ball, causing the core ball to thaw by exposing the core ball to microwave radiation for heat thawing, thus eliminating the possibility of moisture condensation on the core ball, the core being thawed without substantial heating of the rubber thread; and

enclosing the core ball in a cover.

2. The method of claim 1 wherein the core is a liquid center.

3. The method of claim 1 wherein the microwave irradiation is initiated within 120 seconds after the completion of thread winding.

4. The method of claim 1 wherein the microwave irradiation is continued for a time of from about 5 to about 20 seconds per core when a liquid center frozen at -70°

C. to 80°

C. is heated with microwave at an output of about 600 watts and a frequency of 2420 to 2480 MHz.