Automatic lead advancing mechanism for a mechanical pencil
US4538934A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 5, 1983 |
| Grant date | Sep 3, 1985 |
| Priority date | — |
| Expiry date | Aug 5, 2003 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB43L13/024
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
An automatic lead advancing mechanism for a mechanical pencil has at its writing point a lead guide tube which is movable axially against a clamping member to cause radially movable components of the clamping member to clamp the lead therein during the writing position of the pencil. The lead guide tube moves axially inwardly against a force exerted by a compression spring interposed between the clamping member and a thrust member, a portion of which is engaged by the lead guide tube and another portion of which has a beveled surface engaging a correspondingly beveled surface on the clamping member. The co-acting beveled surfaces exert both axial and radial forces to the clamping member.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.