Apparatus and method of making hollow articles
US4130619A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 16, 1977 |
| Grant date | Dec 19, 1978 |
| Priority date | — |
| Expiry date | Jun 16, 1997 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/54
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention is directed toward making hollow racquet ball balls. This is accomplished by molding a mass of vulcanizable elastic material to hollow semi-spherical form and heating the bulk of the material substantially fully to vulcanize it while simultaneously cooling a portion around the full edge so it is only partially vulcanized at the edge area thereof. Then two of such semi-spherical forms have the edges thereof abutted under some pressure to force the uncured edges together, and heat is then applied to the uncured edges of each half to fully vulcanize them and bind them together to form a unitary seamless ball thereform. Apparatus for forming the balls includes mold means defining a hollow semi-spherical cavity with a cooling chamber being provided at the open edge of the cavity that defines an edge of the formed hollow half sphere whereby a cooling medium can be circulated at the edge to prevent vulcanization thereof while the remaining part of the hollow half sphere is heated and vulcanized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.