公开(公告)号：US3767740A

公开(公告)日：1973-10-23

申请号：US3767740D

申请日：1971-06-24

Applicant: DUNLOP LTD

Inventor： JONES HINTON J ,  GRAY T

IPC: B29C51/10 ,  B29C65/00 ,  B29C65/04 ,  B29C65/72 ,  B29C69/00 ,  B29D22/04 ,  B29C17/04 ,  B29C17/08 ,  B29C27/04

CPC classification number: B29D22/04 ,  B29C51/10 ,  B29C51/267 ,  B29C65/04 ,  B29C65/72 ,  B29C66/1312 ,  B29C66/3282 ,  B29C66/54 ,  B29C66/71 ,  B29C66/73921 ,  B29C66/81415 ,  B29C66/81423 ,  B29C66/81427 ,  B29C66/81431 ,  B29C66/8322 ,  B29L2031/54 ,  B29K2077/00 ,  B29K2069/00 ,  B29K2061/04 ,  B29K2055/02 ,  B29K2027/06 ,  B29K2023/16 ,  B29K2023/065 ,  B29K2001/14 ,  B29K2001/12

Abstract: A METHOD FOR FORMING TABLE-TENNIS BALLS FROM A LARGE NUMBER OF THERMOPLASTIC MATERIALS INCLUDING POLYVINYL CHLORIDE AND TERPOLYMER OF ACRYLONITRILE WITH BUTADIENE AND STYRENE, WHICH INCLUDES THE STEPS OF ALIGNING TWO HEMISPHERES OF A RIGID THERMOPLASTIC MATERIAL TO FORM A SPHERICAL CAVITY, SUBJECTING THE EDGES OF EACH HEMISPHERE TO A HIGH FREQUENCY, ALTERNATING ELECTRIC CURRENT TO SOFTEN AND ADHERE TOGETHER THE EDGES TO FORM A BUTT-JOINT AND FORMING A REINFORCING BEAD ON THE INSIDE SURFACE OF THE BALL AROUND THE BUTT-JOINT.