Valve gated injection molding apparatus with a spring in the piston
US5334010A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 19, 1994 |
| Grant date | Aug 2, 1994 |
| Priority date | — |
| Expiry date | Jan 19, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/281
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Valve gated injection molding apparatus with a spring mounted on a central pin adjacent the head of a valve member in a spring chamber in each of the pistons. The spring is compressed between the base of the pin and the cap of the piston to preload it. When the valve member and piston are driven forwardly to the closed position, the head of the valve member retracts somewhat into the spring chamber against the force applied forwardly against the head of the valve member by the spring. This cushions the impact of the front end of the valve member in the gate and provides for tight seating of the front end of the valve member in the gate without requiring all of the components to be made to precise tolerances with exact allowance for thermal expansion. The spring is a number of selected disc springs stacked in sets facing in opposite directions, from which the force applied to the head of the valve member is predetermined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.