Cordless, balanced window covering
US5531257A · kind A · utility
89Cited by
18References
20Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 9, 1994 |
| Grant date | Jul 2, 1996 |
| Priority date | — |
| Expiry date | Sep 9, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S160/17
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A cordless, balanced venetian blind or shade with a constant, or a variable force spring motor includes conventional window covering components without the outside hanging lifting cords or cord locking mechanisms. One or more spring motors are employed. A cord spool, in the preferred embodiment, is coupled to one of the spring drums to serve to wind the cords to cause the blind to be raised or lowered, simply by manipulation of the bottom bar of the blind system. Due to the spring forces, the system compensates for the increasing weight on the cords as the window covering is raised and for the decreasing weight as it is lowered.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.