Control device of window covering system

A control device for reducing an expansion speed of a covering material of a window covering system, the window covering system comprises the control device, the covering material and a weight member attached below the covering material to provide a weight force to the covering material, and the control device comprising:

• a driving module comprising:
• a drive member;
• and
• a spring having two ends, wherein one end is connected to the drive member to provide a restoring force to the drive member to resist the weight force of the weight member, and the restoring force is less than the weight force;
• a lifting module comprising:
• a winding device configured to operate with the drive member and the covering material simultaneously, and wherein the winding device is rotated in a first direction when the covering material is expanded;
• an unlocking module comprising:
• a rotating member configured to operate with the winding device simultaneously;
• a locking member configured to lock the rotating member so as to restrict the first direction rotation of the winding device;
• and
• a control member configured to drive the locking member to unlock the rotating member so as to allow the winding device to rotate in the first direction;
• and
• a damping module configured to operate with the winding device simultaneously in only one direction for providing a damping force to the winding device selectively, wherein the damping force is provided to the winding device for reducing the expansion speed of the covering material when the winding device is rotated in the first direction, and wherein no damping force is provided to the winding device when the winding device is rotated in a second direction opposite to the first direction;
• wherein the control member is configured to be moved by a force other than the restoring force provided by the spring, whereby to drive the locking member to unlock the rotating member so as to allow the winding device to rotate in the first direction;
• wherein a speed change module is provided between the rotating member and the damping module, and the speed change module comprises gears of different gear ratios.