Page 224 - Lego Mindstorms

Robot 8 • The ULK (Useful LEGO Knowledge)

Bricks & Chips…

LEGO Connections
LEGO connections are really strong in compression (the force that
pushes the bricks together) and in shear (the force that tries to slide the
bricks across each other), but they are relatively weak in tension (the
force that tries to pull them apart).
When I first built ULK, I supported the #10 axle on both ends using
1x2 beams reinforced with plates on the top and bottom. The snap-on
connections proved too weak (in tension) to hold the bevel gears
together when ULK tried to raise its arm. The improved support bracket
is attached directly to the side beams. The large forces that used to tear
the arm apart are now in shear across the three-quarter length pins.
The pins can easily counteract the forces, allowing ULK to raise and
lower its arm without concern.

Arm Step 3

Arm Step 4

The double-
high stack of plates
on the bottom of
the arm provides
mounting holes for
ULK’s light sensor.

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