Gripper Attachment for CyberBrick Forklift

How it works:

Assembly Process:
 

Background Story:

This project grew out of a grade 8 school assignment where my son needed to research and design different mechanisms. What better way to learn than by combining SOLIDWORKS with hands-on making?
He started by printing, assembling, and programming the Official CyberBrick Forklift, which gave him a good start in evaluating a mechanical design combined with robotics. 

His first custom add‑on was the Carpet Ram attachment, a simple but effective tool, though not a true mechanism.
The next challenge was to design something that moves and acts, a mechanism with purpose. Inspired by real-world forklifts that handle barrels and containers, he created this Gripper Attachment, using the 180 degree angle servo that comes with the Ultimate hardware kit.

Initially he was thinking of using just two gears with a 1:1 ratio, but that generated jerky movement. The gripper would close too fast, sometimes knocking the objects out of its reach.
That was great as a learning moment, because it force him to learn about reducers. He needed to reduce the speed by half and this is what he did in the end, by adding a first stage of 2:1 gear ratio followed by a 1:1 ratio for the fingers of the gripper.

You can see more about this thought process in this video:
 

CyberBrick Programming:

The JSON file is included but you might want to do the programming yourself. This is what we did:

For the Forklift:

Using the Forklift template, we programmed the S4 port for the 180 degree servo PG0001.
 

Modify its definition:

as follows:

For the Receiver:

Edit the L Shoulder 3-Pos functions:

as follows:

Printing process:

Do not scale anything. Minimal supports have been included, but are very easy to remove. 

Initially, we printed the fingers in PLA, but we found out that a softer material like TPU 95A would be grippier on smooth surfaces. Plate two has the TPU fingers.

Enjoy and provide feedback!

Feel free to remix it as much as you want. I imagine different finger geometry can be used for all kind of other applications. If someone does not fit properly or is not clear, simply ask me. 

We tinkered a lot to get this gripper attachment to fit perfectly and operate smoothly. That being said we are sure it can be further improved.