Let's take a look at this winch in this youtube video [link below](way to small to lift an elevator but still the same principle). If I were to use this winch in a dumbwaiter to lift a load of 100lbs (no counterweight / lifting straight up) are you saying that the 100lbs load would turn the input (the worm) and descend?
https://www.youtube.com/watch?v=LUYqVE1R2KA Firstly I would assume that when it states its 'self locking' (depending on any 'locking feature' on the worm gear ie caravan winders that have that clicking sound which is a reverse lock), I would imagine it has a load maximum and that it depends on runaway characteristics as well ie if the load is down hill. So if the winch is over loaded then it can runaway. Remember to that a dumbwaiter is also an 'old style' hoist ie a drum drive system which also has a braking system either a drum brake on the old units or a disc brake on the new units like a overhead crane motor.
