Make a GBC of the Cat D11 Bulldozer

So many things are happening, GBC balls are rolling everywhere in the GBC 51 Gravel Works. With 6 modules and many paths for the balls to roll over, this GBC has a little bit of everything. PV-Productions, the famous makers of GBC machines (Great Ball Contraptions), have made another great machine. This time from the set 42131 Cat D11 Bulldozer (App-Controlled). Happy to tell all about this amazing GBC themselves.

"One of our new models at the GBC 51 Gravel Works is the Wave Machine. As the name suggests, it generates a wave that pushes the GBC balls forward. It is built using the large angled panels that create a zigzag pattern across the 7 individual surfaces. Because the surfaces are very wide, it can hold many GBC balls at once. This is why it is also used to hold the large tilt plate. The whole machine is driven by a long shaft at the bottom, which in turn drives all 6 levers synchronously. With 7 colorful sections, it is one of the largest modules we have made to date and it is so much fun to see in action. A big upsell is the height gain where the GBC balls roll up 7 studs higher when they reach the end. Always important for most GBC modules."

"As the GBC balls leave the wave machine, they roll at their own pace to the loading stage of the vertical elevator platform. Here, many balls can wait for the platform to lower and pick them up. Another motor will lower the platform and pick up the GBC Balls. After a few seconds, the platform will automatically rise again to the top where the GBC balls are dropped onto the dual conveyor module. All timing is done software-wise, as this offers so many possibilities for users to easily change the behavior and get more interaction."

"With the new yellow conveyors, we knew the Dual Conveyor Module would take the classic module from the GBC 15 Mining Plant to a new level. With the black bars on the belt, this module can handle many more GBC balls. By default, the support legs are fixed and the GBC Balls will move up 23 cm (9 inches). However, if you decide to use the module as a standalone, you can move it up and down by changing the linear actuators in the support structure."

"Once atop 33 cm (13 inches), the GBC Ball rolls down along multiple routes. A flip flop mechanism ensures that the GBC Balls are evenly distributed along the 2 paths. The left path carries the GBC Balls directly to the golf machine so that this module never runs dry. The right path carries the GBC Balls along the zig-zag path where optionally 2 GBC Funnels can also be installed. If you want that extra epic-nes, you can purchase our GBC Funnel XL - Left and our GBC Funnel Gravity Well - Right. After installation, it takes about 25 seconds, if not longer, for the GBC balls to roll down onto the tilt plate. Note that the GBC funnel is completely optional and the GBC can also operate without a funnel."

"We always love it when at certain times in the GBC a lot of GBC balls enter the modules at the same time. That's where the tilt plate comes in. Don't you also love the tension when the plate tilts and drops the GBC balls? In the past we have also included this in our GBC 41 Power Pit Mania where the big shovel from the LEGO 42100 set acts as a bucket. The tilt plate can hold just over 40 GBC balls, after which it falls. It is important that the next module in line can handle these loads of GBC balls. It is also important that the GBC Balls find a way to come back apart in smaller quantities. This brings us back to the Wave Machine which can solve both problems."

Building this model yourself

Want to get started making this GBC yourself? Then you can purchase the instructions for it through PV-Productions. On their website you can also purchase the optional Funnel or USB power box. Have you made this machine or designed your own GBC and want additional balls for your machine? These are available from ToyPro in 3 different colors and with different prints. That way you can easily track the balls as they roll through the machine.