Method for producing injection molded and centrally apertured disc records
US4085178A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1976 |
| Grant date | Apr 18, 1978 |
| Priority date | — |
| Expiry date | Jun 9, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/81
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Heated material is injected into an annular cavity, defined by a pair of mold-halves, through a sprue passage, defined by a sprue bushing and an end portion of a punch. The annular cavity and the sprue passage form, respectively, the centrally apertured part and a sprue. After partial cooling of the heated material, the punch is locked in place while the annular cavity is displaced relative to the sprue passage so that the sprue is severed from the part along the peripheral surface of the punch end portion. The mold halves are separated to open the annular cavity while the sprue is resting on the punch end portion, and while the part is held by the punch end peripheral surface. After the mold halves are separated, a sprue ejector member and a part ejector member are actuated to eject, respectively, the sprue and the part from the punch end portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.