Apparatus and method for fabricating polycarbonate skylights
US4352776A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 1981 |
| Grant date | Oct 5, 1982 |
| Priority date | — |
| Expiry date | Feb 2, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C51/428
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for molding a polycarbonate plastic sheet into a skylight dome or the like. A clamp frame is preheated to a first temperature. A polycarbonate plastic sheet is thereafter clamped around its perimeter in the preheated clamp frame and preheated to approximately the first temperature. The unclamped portion of the plastic sheet is heated to about 300.degree. by ovens to soften the plastic for forming. The softened plastic sheet is then subjected to forming by a pair of coacting peripheral heated molds to form steps and pushes in the plastic sheet immediately adjacent to the clamp frames. A vacuum is drawn over the center portion of the sheet to free-form a dome. The molds are separated and the formed article is removed from the heated clamp frame. The steps of preheating the plastic sheet perimeter in the heated clamp frame and heating of the peripheral molds prevents distortion of the flange area of the slylight dome and of the step and push areas of the dome.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.