Patent ID: 8893763
Filing Date: 2014-11-25
Classification: E06B

Abstract:
1. A pull cord device adapted to control raising and lowering of a base rail relative to a header rail of a window covering in an upright direction, said pull cord device comprising: a container to be disposed on one of the base rail and the header rail; a spring driving unit disposed in said container and including a cord spool and a spring motor that biases said cord spool to rotate in a cord-winding direction; a pull cord having one end coupled to said cord spool, extending out of said container, and further having an opposite end to be coupled to the other one of the base rail and the header rail; a braking unit disposed in said container and operatively associated with said cord spool and said pull cord for retaining releasably the base rail at a desired height relative to the header rail; and a one-way damper unit including: