FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA
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drivetrain. In Figure 67, because there is an even number of gears in the drivetrain the wheels will always spin in opposite
directions, which would get that robot nowhere fast.
Figure 66: Correct All Gear Drivetrain
Figure 67: Incorrect All Gear Drivetrain
4.1.3
Sprocket and Chain Drive Train
Sprocket and chain is an efficient way to transmit torque long distances in a robot. A common example of this is a
sprocket and chain drivetrain (Figure 68). In this example the sprockets on the ends are linked to the drive wheels and the
center sprocket is driven by a motor (not shown). Because the driving and driven sprockets are all inside the chain, they
all have the same rotation direction. The smaller sprockets on the outside of the chain loop are used to increase the
amount of chain wrap on the driving sprocket.
Figure 68: Example Sprocket and Chain Drive Train
All sprockets on the same side of a chain have the same rotation. In Figure 69, the driving and driven sprocket are inside
the chain and are rotating counter clockwise while the idler sprocket is outside of the chain loop and is rotating clockwise.
