Operating device for rotating a winding roller of a window blind

An operating device for rotating a winding roller of a window blind, the winding roller being rotatable relative to a headrail about a horizontal axis for winding up or winding down a curtain cloth, said operating device comprising:

• a rotating shaft having an upper shaft end which is adapted to be coupled with the winding roller such that a counterclockwise or clockwise rotation of said rotating shaft about an upright axis transverse to a direction of the horizontal axis results in horizontal rotation of the winding roller for a corresponding winding-up or winding-down of the curtain cloth, a shaft body extending from said upper shaft end along the upright axis to terminate at a lower shaft end, said shaft body having upper and lower thread segments which are disposed on an outer shaft surface thereof and which are proximate to said upper and lower shaft ends, respectively;
• a sleeve shell which is disposed to surround and permit said shaft body to be rotatable relative thereto so as to cooperatively define an accommodation space, and which extends in a direction of the upright axis to terminate at upper and lower peripheral ends;
• upper and lower coupling members disposed in said accommodation space and proximate to said upper and lower peripheral ends, respectively, each of said upper and lower coupling members including
• an anchored end which is anchored on said sleeve shell and proximate to a respective one of said upper and lower peripheral ends, and
• at least one finger portion which extends from said anchored end away from the respective one of said upper and lower peripheral ends to terminate at a grip end, and which has a cammed surface that radially confronts said sleeve shell, said grip end having an engageable region which radially confronts a corresponding one of said upper and lower thread segments such that an upper friction engagement between said engageable region of said upper coupling member and said upper thread segment permits the counterclockwise rotation of said rotary shaft when a manual force is applied to move said sleeve shell upward, and such that a lower friction engagement between said engageable region of said lower coupling member and said lower thread segment permits the clockwise rotation of said rotary shaft when a manual force is applied to move said sleeve shell downward;
• and
• an actuating member disposed in said accommodation space and movable relative to said upper and lower coupling members in the direction of upright axis, and having upper and lower inner tubular wall portions, each of which has a camming surface that is configured to mate with said cammed surface of a respective one of said upper and lower coupling members such that, when said actuating member is moved upward from a non-actuating position to an upper actuating position, said engageable region of said upper coupling member is pressed to make the upper friction engagement with said upper thread segment as a result of an upper cam action between said upper camming and cammed surfaces, and such that, when said actuating member is moved downward from the non-actuating position to a lower actuating position, said engageable region of said lower coupling member is pressed to make the lower friction engagement with said lower thread segment as a result of a lower cam action between said lower camming and cammed surfaces.