Method of operating a two-shot injection-molding machine
US4444711A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1981 |
| Grant date | Apr 24, 1984 |
| Priority date | — |
| Expiry date | Dec 21, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/425
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
There is disclosed a method of operating an injection-molding machine to produce a composite item that includes a portion of soft material such as a set of bristles tending to cling to a mold cavity in which it is formed. At a first station, a relatively flexible plastic material is injected into a first cavity shaped to define the portion of soft material of the composite item, that portion including a backing layer. The portion of soft material is then allowed to cool, and at a subsequent station there is injected a relatively rigid plastic material into a second cavity bounded by the backing layer. The second cavity defines a harder portion of the composite item such as a brush handle. After the latter portion has also cooled, the portion of soft material is separated from the first cavity by pulling on the harder portion at a rate of speed slow enough to avoid rupture of the portion of soft material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.