motor\pulley that can hold weight (appox 10lbs) when not being used

I am trying to create a remote for my shades. My shades are top down\bottom up, meaning there is a cord on each side (one raises the bottom, the other raises the top). Currently you need to pull the string to the side to unlock the string, then pull up and down like a regular shade.

My plan was to break the locking mechanism so that if you pull the string, the shade goes up (or down) and you need to hold it. I need a pulley and motor so that when it is at the proper setting, the pulley would stop and be able to hold without power.

If I could find a motor like that, I would simply have to go in one direction to pull up, in the other direction to go down, then stop when at the right height. I can’t supply tension using the motor since most of the time it will be off.

I also need something that is somewhat small so that it can be mounted below the window. I will probably need two for each shade, one for the top and one for the bottom. I will also need a set of these for each of my 4 shades. I have seen small motors, but nothing that will suite my needs.

You should consider attaching the motor to the winder with a worm drive. The worm drive can't be driven by the load so it just stays when the motor stops.

...R

As a bonus, worm drive can give a substantial gear reduction in a compact space.

+1 on the worm drive, simple, fool proof. However worm drives have a drawback, they can damage the driven mechanism through having too much torque. A weaker motor can't always solve this as there is lots of friction in a worm drive so the motor needs enough torque to overcome this, and is thus torquier than really needed... A slipping clutch on the output or limit switches may be needed to protect the shade mechanism (or care when operating it!)

You could counter balance the weight of the shade with a weight on the cord. As a better choice you might consider the below cordless screw driver to wind the cord. Wal-Mart usually carries these for less than $10.

http://www.youtube.com/watch?v=Aw_FJY1ybXo