Brakes

[Tristan Lall]

Originally Posted by Lil' Lavery

A drive system which utilizes worm gears.

Worm gears are nearly impossible to backdrive, so when you're not driving them with your motors, anything powered by a wormgear won't move. Therefore in a drive system, the wheels don't turn when you don't want them to. Worm gears are also terribly inneficient, and you can potentially lose 30% or more of your power in a system using them.

If anyone cares, 772 (Sandwich SS from LaSalle, ON) used a worm drive on each side of their drivetrain (with two small CIMs in total).

The trick with worm gears is that as their efficiency increases, the ability to backdrive them also increases—it's that inefficiency (sliding contact, mostly) that's common in so many of them that permits them to resist being backdriven. Sandwich, if I remember correctly, used custom two-start worms, which were supposed to be reasonably efficient, given the substantial reduction.