Patent ID: 8156993

Claim:
A roll screen control member comprising: a sprocket wheel, a chain protection cover arranged at one side of the sprocket wheel, a sprocket support having a plurality of projecting locking parts whose surfaces project inwardly from a longitudinally extending inner wall of a hole extending therethrough while the sprocket support is inserted through the other end of the sprocket wheel, the surfaces being spaced from opposite ends of said longitudinally extending inner wall, at least one cover spring disposed around one end of the sprocket support that inserts through the sprocket wheel, a splined bush engaged with a roll screen tube, and a central pin including a central pin head with a plurality of flat cut surfaces only at one end thereof and each cut surface matching and corresponding to and matingtly engaged with the corresponding projecting locking parts of the sprocket support after the central pin is locked into the sprocket support while a rear end of the central pin is assembled with the splined bush.