Pull-rod mechanism and window covering having same

A pull-rod mechanism applied to a window covering for operating retraction and extension of the window covering, the window covering having a roller and a covering material connected to the roller, the pull-rod mechanism comprising:

• a drive connector, fixedly connected to an end of the roller so that the roller is rotatable with the drive connector, the drive connector having an inner surface provided with at least one first abutting portion;
• a base, disposed to correspond to the end of the roller;
• a pull rod, disposed below the base, comprising:
• a fixed shaft, fixedly connected to the base;
• an unlocking shaft, at least partially protruding from below the fixed shaft and retractable with respect to the fixed shaft;
• and
• a lift operating member, at least partially protruding from below the unlocking shaft and retractable with respect to the unlocking shaft;
• a lift mechanism, disposed within the base and in mechanical communication with the lift operating member of the pull rod through a lift cord, comprising:
• an annular cord wheel, rotatable around an axial direction of the roller and having an inside circumferential surface formed with plural second abutting portions;
• a rewinding unit, connected to the annular cord wheel such that the rewinding unit drives the annular cord wheel to rotate and thereby resets the annular cord wheel after the annular cord wheel stops being subjected to force;
• and
• a driven member, coaxially disposed with the annular cord wheel within the base and having an outer periphery formed with plural teeth, the driven member comprising plural elastic arms corresponding to the second abutting portions respectively, wherein an end of the lift cord is fixedly connected to the annular cord wheel while another end of the lift cord extends out from the base into the pull rod and is fixedly connected to the lift operating member;
• when the lift operating member is subjected to force and thereby protrudes with respect to the unlocking shaft, the lift cord moves with the lift operating member and thereby drives the annular cord wheel to rotate in a forward direction, making the elastic arms abut against the second abutting portions respectively and drive the driven member to rotate in the forward direction with the annular cord wheel concurrently;
• an unlocking mechanism, disposed within the base and in mechanical communication with the unlocking shaft of the pull rod through an unlocking cord, comprising:
• a moving member, movably disposed within the base and comprising a pushing portion, wherein an end of the unlocking cord is fixedly connected to the moving member while another end of the unlocking cord extends out from the base into the pull rod and is fixedly connected to the unlocking shaft;
• when the unlocking shaft is subjected to force and thereby protrudes with respect to the fixed shaft, the unlocking cord moves with the unlocking shaft and thereby drives the moving member to move in a first direction, making the pushing portion of the moving member engage with the plural teeth formed on the outer periphery of the driven member and drive the driven member to rotate in a reverse direction opposite to the forward direction;
• and
• an actuating mechanism, connected between the lift mechanism and the drive connector, comprising:
• a drive shaft, extending along the axial direction of the roller in which an end of the drive shaft extends into the drive connector and another end of the drive shaft is fixedly connected to the driven member such that the drive shaft is rotatable co-directionally with the driven member;
• and
• at least one swinging pawl, swingably disposed between the drive shaft and the drive connector;
• wherein when the lift operating member is subjected to force and thereby makes the annular cord wheel, the driven member, and the drive shaft rotate in the forward direction, the at least one swinging pawl engages with the at least one first abutting portion of the drive connector and transmits a torque to the roller for retracting the covering material;
• wherein when the lift operating member stops being subjected to force, the rewinding unit drives the annular cord wheel to rotate in the reverse direction;
• while the annular cord wheel rotates in the reverse direction, the elastic arms skid over tops of the second abutting portions, and the annular cord wheel does not drive the driven member to rotate;
• wherein when the unlocking shaft is subjected to force and thereby protrudes with respect to the fixed shaft and makes the driven member rotate in the reverse direction, the driven member drives the drive shaft of the actuating mechanism to rotate in the reverse direction concurrently, making the at least one swinging pawl disengage from the at least one first abutting portion of the drive connector and configuring the drive connector and the roller to rotate freely with respect to the drive shaft under a weight of the covering material for extending the covering material.