Inch Worm

This is the base for the inch worm.
The most important part of the Inch Worm is the pawl and ratchet on each axle.
At this point the motor block Green G instructions are added.
The only difference is that a crown gear is used instead of the 24 tooth spur so that two could be used for ratchets.
Place a 40 tooth gear on the 4 axle. Add a gray connector in an outside hole.

The pawl and ratchet are to be set so that both the front and the back wheels roll only forward.
The middle folds up and the 16 beam connects to the connector in the 40 tooth gear.
As the motor rotates the 40 tooth gear the 16 beam  moves back and forth (actually it is reciprocating motion).
Take care that the axle through the crown gear in the gear box does not come out
of the 40 tooth gear as it would then bind against the beam and stall the motor.

The complete LEGO CAD model of The Inch Worm
using LEGO Educational Motorized Simple Machine set.

LEGO Links of Linda Hamilton