Crank turning mechanism for roller blinds, has front opening formed on slit and encircling part, and front shield, perimeter profile and rectangular side profile provided with bump and central curved concave depression parts

摘要

The mechanism has a hollow box (1) provided above and below an extension coplanar part (2). An upper face of the coplanar part is formed with a hole (4). An encircling part is fixed in the box. A front side of the box is formed with a slit for passing a sheave. A front shield, a perimeter profile and a rectangular side profile are provided with a bump and central curved concave depression parts. A front opening is formed on the slit and the encircling part.