Pencil having an eraser-holding ferrule secured by ultrasonic welding, and a ferrule adapted for that purpose
US5774931A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Jul 9, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB43K29/02
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
In a pencil having a central lead, provided at its top end with an eraser mounted in a ferrule fixed on the body of the pencil, both the ferrule and the peripheral body surrounding the lead are made of thermoplastic materials that are compatible, and the bottom of the ferrule is fixed to the top end of the pencil by localized interpenetration of the thermoplastic materials in at least one ultrasonic weld zone. The material of the peripheral body of the pencil is preferably expanded so as to have a relative density of about 0.5 to 0.6, and the top end of the body includes a setback in which the density has been increased, locally. The ferrule includes a shoulder on the outside face of its bottom, the shoulder being annular in shape and forming an energy director for ultrasonic welding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.