| 摘要 |
<p>The invention concerns a preform in the form of a sheet (51) of plastic material of substantially rectangular shape, apt to be transformed by milling - in known manner - into an eyeglass frame. Said sheet preform comprises hollow parts (F4, F5), with no material, at least in correspondence of the two eye circles and of the nose-piece (F6) of the frame, as well as - possibly - a main portion of narrow thickness and supplementary portions of further thickness at least in correspondence of the nose-piece (8a) and of the supports for the hinges (8c, 8d) of the frame bars. The mold to produce such a preform essentially consists of a flat rectangular chamber (3), wherein a mixture of plastic materials in scales, grains and/or pieces is introduced and hot-pressed, said chamber comprising occlusion inserts (4, 5, 6, 7) apt to define in the preform said hollow parts with no material. Said inserts (9) can also be made of inexpensive yielding material, which is pressed simultaneously with the material in scales, grains and/or pieces.</p> |
