The present disclosure includes a retrofitted door brake cam. The retrofitted door brake cam may, in various embodiments, comprise a hub comprising a cylindrical central axle, a plurality of projections extending radially away from an outer circumference of the central axle, and/or a cam comprising a plurality of pins that hold the projections away from a channel wall of a brake housing. The pins may be configured to break away from the cam to release the projections into contact with the channel wall, and the pins may be fitted with a cover, such that the pins are capable of withstanding abrasion and wear. The cover may comprise a cylinder having an axially running aperture, and/or a beveled edge that shaves a layer of the outer surface from one of the plurality of pins as it is fitted over the pin.

A door includes a door leaf (1) with a vertical running direction and a drive (7) for opening and closing the door. A braking device (8) is provided, and this is configured such that the door leaf (1) cannot be moved in the closure direction solely by a weight force thereof, but only with the assistance of the drive (7).

A chain assembly includes a wheel secured on a shaft. A chain manually rotates the wheel and the shaft. A one way bearing has an inner race secured to the shaft and has an outer race that can freely rotate in only one direction in relation to the inner race. A brake drum is coupled to the outer race. Brake shoes are in operative contact with the brake drum to apply friction to the brake drum when there is relative motion between them. A brake adjuster adjusts the braking force applied by the brake shoes on said brake drum. The one way bearing is arranged to maintain the brake drum stationary in one direction of rotation of the shaft and rotate the brake drum in the opposite direction of rotation resulting in a degree of braking of the shaft as determined by the brake adjuster.

A position-fixing system for a window covering, which has a roller tube, includes a variable diameter screw, a guiding portion, and an elastic member. The variable diameter screw has a working section gradually broadening in a radial direction thereof. The guiding portion extends along an inner wall of the roller tube in an axial direction thereof. The elastic member fits around the variable diameter screw, and is movable along the guiding portion. The elastic member has a meshing portion provided on an inner side thereof to mesh with the working section, and a guided portion provided on an outer side thereof to slide along the guiding portion. When the roller tube rotates in a direction, the elastic member moves along the working section and deforms, whereby to exert a gradually increasing unit tightening force to the variable diameter screw in the radial direction, dampening its rotation.

A door braking system includes: a shaft; a brake pad configured to be mounted to the shaft; a plate for mounting on the shaft adjacent to the brake pad; a spring for urging the plate to the brake pad, the spring configured to be mounted on the shaft; a nut dimensioned and sized to be mounted on the shaft for adjusting an amount of force the spring urges the plate against the brake pad. A method of applying variable amount of braking force to a door includes: attaching a brake pad and brake plate to a shaft; configuring a spring to urge the brake plate against the brake pad; mounting an adjustment piece to the shaft; and configuring the adjustment piece to move axially on the shaft as the shaft rotates to thereby vary a force the spring urges against the brake plate.

An adjustable door braking system includes a shaft, a brake pad configured to be mounted to the shaft, a plate for mounting on the shaft adjacent to the brake pad, a spring for urging the plate to the brake pad, an adjustment piece, and a seat. The spring is configured to be mounted on the shaft. The adjustment piece is dimensioned and sized to be mounted on the shaft for adjusting an amount of force the spring urges the plate against the brake pad. The seat allows the adjustment piece to move axially along the shaft and limit the adjustment piece from rotating with the shaft. The seat is movable between an engaged position where it contacts the adjustment piece to prevent rotation of the adjustment piece and a disengaged position where it does not contact the adjustment piece.

The invention relates to an operating mechanism for a cordless window covering such as a roller blind, comprising at least one substantially stationary inner shaft which is connectable to the fixed world and at least one axially rotatable drive shaft configured for driving and thereby lowering and/or raising the window covering. The system is in particular configured to provide controlled operation of a cordless window covering.

A speed regulating assembly for coupling to a roller tube for regulating a deployment speed of a covering of an architectural-structure covering is disclosed. The speed regulating assembly may include a detachable adapter for enabling a singular sized speed regulating device to be used regardless of the size of the roller tube. That is, by utilizing a detachable adapter for coupling to the roller tube, any change in the size of the roller tube only requires a different sized adapter. In addition, the speed regulating assembly may be configured so that during covering retraction, the speed regulating assembly is disengaged so that any input rotation from the roller tube is not transmitted to the speed regulating device. However, during covering deployment, the speed regulating assembly is engaged so that any input rotation from the roller tube is transmitted to the speed regulating device thereby regulating the speed of covering deployment.

A brake arrangement, for a retractable screen arrangement in which the a screen roller applies a retraction force to the screen and brake arrangement, includes a brake arrangement, for providing a braking force between the brake arrangement and a track which guides the brake arrangement, to resist retraction. The brake arrangement provides a brake member with a friction surface for contacting the bearing surface; a brake member support for supporting the brake member; and a forcing arrangement for forcing the friction surface against the bearing surface. The forcing arrangement includes a biasing arrangement for biasing the friction surface onto the bearing surface, and a force-increasing arrangement for increasing the force with which the friction surface engages the bearing surface. The force increasing arrangement converts a frictional force between the friction surface and the track into additional contact pressure force of the friction surface onto the guide track.

A control structure for a window covering includes a base, a revolving wheel having an axial post, a restriction means including a bushing fitting around the axial post, a transmission member provided on a side of the bushing, and at least one pawl connected to the axial post. The revolving wheel is connected to the base. The restriction means has at least one cutting groove. The transmission member has at least one abutting portion on an inner wall thereof. The pawl is pivotable within a width of the cutting groove. When the revolving wheel is rotated forward, an end of the pawl passes through the cutting groove to mesh with the abutting portion. When the revolving wheel is rotated backward, the pawl disengages from the abutting portion, and the transmission member is rotatable relative to the revolving wheel. Whereby, it could prevent generating noise while operating the window covering.