Process for forming string

• US 4,168,606 A
• Filed: 05/31/1977
• Issued: 09/25/1979
• Est. Priority Date: 05/31/1977
• Status: Expired due to Term

• Current Assignee: Goodyear Tire & Rubber Company
• Original Assignee: Goodyear Tire & Rubber Company
• Inventors: Callander, Douglas D.
• Primary Examiner(s): Watkins, Donald
• Application Number:
  US05/801,490
• Time in Patent Office: 847 Days
• Field of Search: 57/139, 57/140 R, 57/140 C, 57/149, 57/153, 57/162, 57/164, 57/3, 57/6, 57/34 HS, 57/144, 57/157 R, 57/157 TS, 57/ 157 MS, 57/236, 57/241 , 57/242, 57/287, 57/288, 57/292, 57/310
• US Class Current: 57/310
• CPC Class Codes: A63B 51/02 Strings; String substitutes; Products applied on strings, e.g. for protection against humidity or wear
• CPC Class Codes: D02G 3/28 Doubled, plied, or cabled threads D02G3/32, D02G3/36 take precedence; effect yarns D02G3/34; details of spindles, e.g. bearings D01H7/86
• CPC Class Codes: D02G 3/444 Yarns or threads for use in sports applications strings for tennis rackets A63B51/02

Abstract

The invention of this application relates to strings for game rackets which are formed of large monofilaments of thermoplastic, fiber-forming resin in which the monofilaments are twisted to form a bundle and two or more bundles are cabled and twisted in the opposite direction from the twist of the bundle, the composite string being oriented and heat set to prevent unravelling of the string. The strings are laced into a game racket such as a tennis racket under a tension of about 50 pounds to form a racket which has good playing properties as well as tensile retention and good resilience retention.

Claims

1. A game racket strung with a string of from 45 to 60 mils in diameter and having a convoluted surface and consisting of at least one bundle of at least two polyethylene terephthalate monofilaments, said monofilaments ranging from 8-30 mils in diameter and wherein said string is prepared by orienting said monofilaments to provide tensile strength, tensile retention and resiliency then combining and twisting together said oriented monofilaments into the bundle forming the string and then heat setting the string so formed.

2. The game racket of claim 1 wherein the string has a denier of at least 14,000 and a breaking strength of 100 pounds at 20 percent elongation.

3. A game racket strung with a string having a convoluted surface said string characterized by consisting of a bundle of three large polyethylene terephthalate monofilaments (3×

27 mils (0.69 millimeter)), wherein said string is prepared by a method comprised of orienting said monofilaments to provide tensile strength, tensile retention and resiliency and then combining and twisting together said monofilaments at 3.5 turns per inch into the bundle forming the string and then heat setting the string so formed in an oven, said string further being characterized by having a diameter of about 54 mils (3.7 millimeters) and a breaking strength greater than 100 pounds at an elongation of 20 to 40 percent.