Page 231 - Lego Mindstorms

Robot 8 • The ULK (Useful LEGO Knowledge)

Arm Motor Step 2 Arm Motor Step 3

Bricks & Chips…
Worm Gears

The efficiency of a worm gear is much lower than that of normal gears
because the worm works primarily by sliding, thus increasing frictional
losses. This has an unusual side effect in that the worm gear is asym-
metric and self-locking. You can turn the input shaft to drive the output
shaft, but you cannot turn the output shaft to drive the input shaft.
ULK uses the worm gear’s self-locking feature to hold the arm in the
raised position.

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