Cordless, balanced venetian blind or shade with consistent variable force spring motor
US5482100A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1994 |
| Grant date | Jan 9, 1996 |
| Priority date | — |
| Expiry date | Apr 6, 2014 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE06B9/60
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A cordless, balanced venetian blind or shade with a constant variable spring motor includes conventional window covering components without the outside hanging lifting cords or cord locking mechanisms. One or more constant variable force spring motors are employed, preferably comprising springs which vary in thickness or in width along their length as they are wound around storage drums. 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 difference in thickness or width of the spring, 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.