Pencil comprising a marking core and a porous resin sheath
US3993408A · kind A · utility
14Cited by
5References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1974 |
| Grant date | Nov 23, 1976 |
| Priority date | — |
| Expiry date | Oct 29, 1994 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/12
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Pencils made with a resin-based sheath to replace wood sheaths. A sheath material consisting essentially of a resin binder, a fibrous filler and a metallic soap is extruded around a marking core. The resulting extrudate is immediately chilled after leaving the die, and cut into pencil lengths. The apparatus includes core feeding and transport means, core preheating means and chilling means. The resulting pencils possess the physical qualities associated with wood-sheathed pencils due to the fine, closed cell structure of the sheath material. The surface of the sheath is smooth and may be coated with a pigmented resin or painted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.