The Worm Winch has arrived! It has been mated to the test stand and has gone through preliminary testing. With a simulated 40 pound load and a battery powered 0.5 In. drill, the system is able to move the load in about 12 seconds.
Please see the test video below.
The other critical test is the self braking test. If the drill is stopped at midpoint, the load does not move back down the track. In winch speak, this means there is no freewheeling. This also means that when the cart is empty, Dave must reverse the drill to move the cart to base of the stairs. Safety appears to have been attained with lifting. My only other concern is pinch points.
As the worm gear is exposed, there is the risk of pinching / entanglement. A guard will need to be designed to eliminate this risk. Overall, very pleased with lab testing.
Next step, field testing!