Crawler Crane: A LEGO® creation by Halhi 141 : MOCpages.com

Crawler Crane

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A technic crawler crane. It uses a motor and a lever to move the boom and hook.

About this creation

This crawler crane has several functions. It can pivot the top half of it, it can raise and lower the boom, and it can move the hook. Additionally, it can drive on its wide tracked driving base.

The model can split into two halves. This made it easier to build, especially when building the pivoting mechanism (the last part that I built).

Here you can see the medium motor with a 12t gear connected to it. It turns 3 20t gears. It turns 3 instead of just one because the axle that the 20t gears are on moves back and forth.

On that axle, there are also two gears and a structure made out of some castor wheels. This is the multiplexer that allows just one motor to control two functions. It is switched by a manual switch that you can see on the right of the picture. Two technic teeth are used to move the castor wheels and the rest of the axle back and forth.
The multiplexor has three positions. The first position is when the lever is pointed forward. When it is pointed forward, the axle moves backward so that the gears at the bottom of the picture engage. These gears control the hook. The second position is the middle, neutral position in which neither of the two gears are engaged and the motor does not move any functions. The third and final position is when the motor is pointed backward. The axle moves forward and the gears near the top of the picture engage. These gears move the boom.
In the picture, the multiplexor is in the second position.

The multiplexor in the third position.

The multiplexor in the first position.

The gear shift can be controlled by the grey lever or the red lever in the cabin. The cabin's door can open.

When the multiplexor is in the third position, the motor controls the mini linear actuator that moves the boom.

When the gear shift is in the first position, the motor controls the winch via a worm gear and 24t gear.

The winch, made with 2 24t gears and 4 3m friction pegs.

The boom and hook. The boom is reinforced with lots of trapezoids so that it is realistic and sturdy.

I used an IR remote and receiver to control this rather than just using the battery box. This is because when only the battery box lever is used, often when I try to turn the motor off, it just moves in the opposite direction. I would have used a PF switch, but I do not have one,
The battery box is covered by a small scoop to continue the yellow color scheme.