A window shade system may comprise a drive mechanism having a friction slip ring inside a brake hub, wherein the brake hub is configured to rotate with respect to the friction slip ring, in response to an at least partial rotation of the drive mechanism. The brake hub may be configured to overcome a break-away force between the drive hub and the friction slip ring. The brake hub may be configured to overcome a break-away force between the drive hub and the friction slip ring. The brake hub may be configured to overcome a break-away force of about double a maximum force that a window shade exerts on the friction slip ring. The system may include a spring plunger system abutting a bracket, wherein the spring plunger system may be configured to reduce friction against the bracket in response to a first at least partial rotation of a drive mechanism.

Proposed is a roller blind drive device preventing an accident due to a drive cord, the drive device being configured to lower or raise a curtain fabric by performing forward/reverse rotation of a drum on which the curtain fabric is wound, the drive device including a fixed part, a rotating part mounted rotatably to the fixed part and configured to perform the forward/reverse rotation of the drum, a circular drive cord having a front cord and a rear cord, and a manipulating part connected to the drive cord exposed to the lower side of the fixed part. Accordingly, the drive cord is covered so as not to be seen from the outside, and any one drive cord of the two drive cords is held by the rotating manipulation of the manipulation tube.

Proposed is a roller blind drive device preventing an accident due to a drive cord, the drive device being configured to lower or raise a curtain fabric by performing forward/reverse rotation of a drum on which the curtain fabric is wound, the drive device including a fixed part, a rotating part mounted rotatably to the fixed part and configured to perform the forward/reverse rotation of the drum, a circular drive cord having a front cord and a rear cord, and a manipulating part connected to the drive cord exposed to the lower side of the fixed part. Accordingly, the drive cord is covered so as not to be seen from the outside, and any one drive cord of the two drive cords is held by the rotating manipulation of the manipulation tube.

A roller blind assembly includes a blind roller, a clutch assembly that includes a bracket engagement member, and a pre-torsioned spring assembly that includes a spring. The pre-torsioned spring assembly is positioned in an interior cavity of the blind roller, and exerts a torque proportional to a preset torsion of the spring to promote rotation of the blind roller relative to the bracket engagement member. Rotation of the blind roller relative to the bracket engagement member in a first direction decreases torsion in the spring while rotation of the blind roller relative to the bracket engagement member in a second direction increases torsion in the spring. The pre-torsioned spring assembly is preferably selected from a group of at least two pre-torsioned spring assemblies, each spring assembly having a different spring preset torsion.

The present disclosure concerns a roller blind limiter assembly comprising a support-engaging member, a limit screw and a limit nut threadedly engaged therewith, operatively connectable to a roller blind tube and travelling along the screw upon extension and retraction of a blind, wherein, in use, the limit nut abuts a winding stopper of the limit screw when the blind reaches upper and/or lower end positions. The roller blind limiter assembly is configurable in a locked configuration wherein the limit screw is fixedly mountable to the roller blind support, and an unlocked configuration wherein the support-engaging member is pivotable about the longitudinal direction with respect to the limit screw. The present disclosure also concerns a roller blind mechanism and a roller blind system comprising such a limiter assembly, and a method for adjusting an end position of a roller blind.

Disclosed is an electromechanical actuator including a spring brake including a helical spring, a drum, an input member and an output member. The drum includes a friction surface configured to cooperate with at least one turn of the spring. The output member includes at least one lug. The lug includes a recess provided with at least a first bearing surface configured to cooperate with one of the first and second legs of the spring. The first bearing surface of the recess is inclined with respect to an axis of rotation of the brake at an angle of inclination of non-zero value.

Disclosed is an electromechanical actuator including a spring brake including a helical spring, a drum, an input member and an output member. The drum includes a friction surface configured to cooperate with at least one turn of the spring. The output member includes at least one lug. The lug includes a recess provided with at least a first bearing surface configured to cooperate with one of the first and second legs of the spring. The first bearing surface of the recess is inclined with respect to an axis of rotation of the brake at an angle of inclination of non-zero value.

A cordless roller blind includes a roller tube, a blind fabric wound around the roller tube, and at least one brake device. A coil spring is arranged in the roller tube, and the torsion of the coil spring changes as the roller tube rotates. The torsion force of the coil spring, the friction force provided by the brake device and the weight of a hanging portion of the blind fabric are mutually balanced, so that the blind fabric remains stationary at any position without an external force. When the external force pushes the blind fabric to move upward, pressure acting on the brake device decreases as the external force offsets the weight of the blind fabric, and the friction decreases accordingly, and the torsion force of the coil spring drives the blind fabric to wind up.

A cordless roller blind includes a roller tube, a blind fabric wound around the roller tube, and at least one brake device. A coil spring is arranged in the roller tube, and the torsion of the coil spring changes as the roller tube rotates. The torsion force of the coil spring, the friction force provided by the brake device and the weight of a hanging portion of the blind fabric are mutually balanced, so that the blind fabric remains stationary at any position without an external force. When the external force pushes the blind fabric to move upward, pressure acting on the brake device decreases as the external force offsets the weight of the blind fabric, and the friction decreases accordingly, and the torsion force of the coil spring drives the blind fabric to wind up.

Disclosed is an electromechanical actuator including a spring brake including a helical spring, a drum, an input member and an output member. The drum includes a friction surface configured to cooperate with at least one turn of the spring. The output member includes at least one lug. The lug includes a recess provided with at least a first bearing surface configured to cooperate with one of the first and second legs of the spring. The first bearing surface of the recess is inclined with respect to an axis of rotation of the brake at an angle of inclination of non-zero value.