Caterpillar Tracks & Track Hub

---Today's Piece---

Name: Caterpillar Tracks and Track Hub

Size: varies

Color(s): varies



I was going to do these pieces as two seperate blog entries, but then I decided to combine them, since they're related.

Here we have a caterpillar track (colored black), and two hubs used for it (colored yellow). The track fits around the hubs, which are shaped to grip the track.

Here' s a close-up of one of the hubs. Notice the small bumps around the outside edges. These bumps push bumps in the inside of the track, moving the track when the hubs turn. One can also insert an axle inside the center of the hub, and use that to propel the tracks.

This is the outside of the track. The bumps help the track to grip whatever surface it is moving on, be it smooth or rough. I frequently build my robots with two tracks like this for movement, for several reasons:

• Easy to use for steering; just stop one track, or run them in opposite directions.


• Simple to build; usually only one simple gear mechanism is needed between the motor and the axle the tracks are on.


• When both motors are run the same direction, the robot usually moves in a straight or almost straight line without any correction needed.


• One motor for each track leaves a motor port spare. Since the Lego microcomputers only have three motor ports, this is a good thing.