| 摘要 |
The present invention provides a roller shade with a variable load brake and, in a modification thereof with a lift assist. The load brake includes a compressible spring surrounding a threaded rod, the spring acting against a traveling nut mounted on the rod. The compressive friction of the traveling nut against the threads of the threaded rod continually varies during raising and lowering of the shade to provide the variable load braking capability. The lift assist uses at least one torsion spring, also associated with a shaft and coupled between a nonrotating flange and a nipple rotationally anchored to the shaft. The torsion spring system is increasingly loaded when the shade is lowered.
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