Problem with rope climbing mechanism

[satman1]

Hi,
I need to figure out how to design a device that should climb on a rope without any
electrical or chemical plant (see the attached file for drawing).
I need a good idea how to generate sufficient lifting force in order to compensate weight
and friction?

 

[Travis_King]

You can use a mechanical power supply, right? Such as a winded/loaded spring?

 

[NascentOxygen]

I've been pondering this, and can't decide whether my scheme needs > 100% efficiency. I'm sure someone will soon set me right.

Allow that weight on the string to slowly fall and unravel from the pulley, and this turns the pulley so it advances up the rope. Is there a payload to lift, or just the light-weight pulley?