US Patent 11060347 Window shade assembly

A window shade assembly includes a top box with two end members respectively connected to two ends of the top box, a shaft, a shade and a scrolling unit. The scrolling unit is received in the shaft and located between the two end members. The scrolling unit includes two end parts, a head, a spring and a movable member. By rotating the head to activate the spring to store a scrolling force, such that when pulling the shade, the end part drives the shaft to rotate and lower the shade. The spring does not pulls the shade upward and keeps its scrolling force at a level. When the shade is pushed upward, the shade is lifted automatically.