It has never been easier to build a complete Great Ball Contraption (GBC) loop yourself! The GBC 50 Tow Lift features 4 modules which brings GBC Balls from one side to the other. The GBC can be used as a self contained loop or participate in a GBC layout.

This GBC is entirely built using only parts from the LEGO 42128 Heavy-duty Tow Truck set and can be referred to as Alternate Build of the 42128. This GBC makes sure you master the GBC building techniques and tricks so that you eventually also can build your own GBCs. By default the whole machine is powered by hand but it can easily be upgraded with any LEGO motor (more information in the building instructions).

Taking on some new tension!

The GBC 50 Tow Lift combines so many cool aspects that we know for sure you are going to like this one. To name a few: pulleys, pneumatics, timings mechanisms, clever universal joint usage and so much more! On top of this there are also interactive play elements included so you there is always something to do, instead of just watching.

Let start at the beginning. The GBC 50 Tow Lift features 4 main modules starting with the Tow Lift Module, hence the name. This module is inspired by those maintenance bridges you see hanging on the side of those tall sky scrapers. When you rotate the drive handle to the left the platform lowers to pick up the GBC Balls at the bottom. An automatic gate will open up once the platform is al the way down. Then it up to the user to confirm the correct loading of GBC Balls and rotate the drive handle to the right again. This will raise the platform again all the way to the top. Another automatic gate opens up at the top so the balls can pas through. We have implemented a safety timings feature which makes sure that you can never overdrive the mechanism and break something. This safety feature does also come in handy when the platform is in the lower position to keep the rope properly tensioned.

Next up is our GBC Funnel XL – Left. This funnel is, as always, optional but I can’t tell you how fun it is to watch a dozen of GBC Balls go into the GBC Funnel at the same time. The sound it makes, oh stop it!
This leads the GBC Balls to the Rotating Cups Module which has a few tricks upon its sleeve. A timings mechanism will pick up one GBC Ball at a time and put it into one of the rotating cups. As this module is put on a slope the cups with GBC Balls will slowly go up. Due to gravity affecting the cups they will always level out which makes for a neat side effect. At the top the cups are being rolled over and the GBC Balls can exit the module. As you are constantly switching the drive direction of the drive handle (due to the Tow Lift Module operation) this would normally result in the Rotating Cups Module to also change rotation direction every time. However due to the timings mechanism and output direction this is a no go. To make sure that the Rotating Cups Module is always rotating in the correct direction we have implemented an automatic direction change mechanism. So no-matter which direction you rotate the handle, things will continue to operate smoothly.

The slope of this module is customizable and can be interacted with during play. 2 long pneumatic cylinders hold the complete weight of the module and can fully raise and lower it. Tip: you can also block the pneumatic cylinders in halfway position by simply putting the valve switch in the middle position. This blocks the complete air flow and you set the slope exactly as you like.

Last but certainly not least there are our Xylophone Keys which can optionally be added to the layout. Depending on the slope you set for the Rotating Cups Module these give a different sound and ring to it. Experiment and discover!

A neat feature of the GBC 50 Tow Lift is its ability to convert with ease into a GBC Layout Module. You can simply add your other GBC Modules to the right side and drop the GBC Balls in the beginning of the Tow Lift Module. You can rotate the Xylophone Keys path and use it as a path to the next module. In this way you can easily connect this GBC to all our other GBCs to make the loop even bigger. More information in the building instructions. Clean and simple: Convert with ease.

Be default the GBC is powered by hand but you can motorize it. However, to make the Tow Lift Module go up and down automatically you need to switch the motor direction manually. Of course you can also automate this and use a motor which can be programmed via e.g. LEGO Powered Up, NXT/EV3 or SBrick/Buwizz. You only have to make a simple program which spins the motor clock-wise for an certain amount of time and followed by spinning the motor counter-clock-wise for the same time. In the building instructions we have carefully explained how to do this in the LEGO Powered Up App.

Fun Fact

LEGO sets which include a rope always gets us thinking of all the possibilities. We have tried multiple ideas like a flying carpet (hold by ropes) or a ski lift. For some reason the idea of a maintenance bridge on a tall skyscraper stuck with us and we tried to pursuit this. To make this a success we set ourselves some goals to make sure everyone can build this. First of all the calibration/fine-tuning should be a simple and straight forward and above all a one time set procedure. Secondly the rope should be hold in place when moving the GBC. And at last of course esthetics are also very important to us. Many iteration came across, all working slightly different but in the end we made is work beautifully.

Building Instructions Preview

Preview

Upgrade your GBC 50 Tow Lift

GBC Funnels

Power & Automate

The GBC 50 Tow Lift all over the world

This model is also included in the GBC Pro Pack