Venetian blind provided with slat-lifting mechanism having constant force equilibrium
US6012506A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jan 4, 1999 |
| Grant date | Jan 11, 2000 |
| Priority date | — |
| Expiry date | Jan 4, 2019 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE06B9/62
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A Venetian blind is provided with a slat-lifting mechanism consisting of a slat set, a slat pull cord, and a constant torque pull set. The slat set has a plurality of slats. The slat pull cord is connected with each of the slats of the slat set and is put through the bottommost end of the slat set. The constant torque pull set is disposed at the top end of the slat set and composed of a pull cord member and a constant torque spring unit which is linked with the pull cord member and provided with a constant torque spring which has a constant retrieving force enabling the pull cord member to rewind. The constant retrieving force of the constant torque spring must meet the condition of W-Fs<R<W+Fs, in which W stands for a total weight of the slat set; Fs, a system static friction force; and R, a retrievable elastic force of the constant torque spring.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.