Patent ID: 7624785

Claim:
A control mechanism for a self-raising window covering, the window covering including a head rail, a suspended shade element, a bottom rail, and at least one raising cord operatively connected at a first end to the bottom rail, the control mechanism comprising: a drive axle; a drive unit operatively connected with the drive axle to apply a substantially constant rotational force on the drive axle; at least one cord winding assembly mounted on the drive axle and including a winding portion having a first end with a first diameter and decreasing in diameter to a second end having a second diameter less than the first diameter, wherein the cord winding assembly is operable under the rotational force applied by the drive unit, to wind the raising cord for raising a suspended weight comprised of at least the bottom rail and a portion of the shade element that is stacked on the bottom rail, wherein the cord winding assembly includes a threaded tubular member that engages with one or more toothed rollers to cause an axial translation of the cord winding assembly along the drive axle as the cord winding assembly rotates; and a clutch member operatively connected with the drive axle, the clutch member being operable to lock the drive axle and block rotation of the drive axle against the rotational force applied by the drive unit, the clutch member further being operable to unlock the drive axle in response to a rotational force provided to the drive axle that is opposite to the rotational force of the drive unit.