How Does a Winch Work?

[generalbrando]

Originally Posted by Raul

The van door motor can be back driven unless the bearing screw (at the end of the worm gear) is tightened quite a bit. The problems with doing this are:
1) You lose power output by tightening it
2) It wears out and you have to keep tightening it to keep it from backdriving

Plus it might still back drive if it sees excessive force.

Also, if you're worried about keeping a motor from slipping (such as when the power gets cut at the end!) you could use a little pneumatic piston to lock something in place. If you were pulling in a cable on spindle like thing (i'm bad at the right names, forgive me) then on the side of that you could have ridges (think raised spokes) and then all you have to do is fire the piston into the side of the thing to lock the spindle in place. As long as you set up the pneumatics right, it won't move when the power gets cut.