PistenBully 600

[MOC] Liebherr 250 EC-B Towercrane 1:18

Recommended Posts

Hello everyone,

My current project is the construction of a Liebherr 250 EC-B towercrane in 1:18 scale. The model is fully functional. The hoist winch is powered by one XL-Motor, the trolley winch uses one M-Motor and the slewing ring is powered by two L-Motors. All motors are controlled by an S-Brick. I have started building this model 4 months ago.

Here the crane is assembled with 110 cm tower and 180 cm jib:

29553919dm.jpg

29553917zy.jpg

29553958ql.jpg

The maximum height under hook is about 2 meters; the maximum jib length is 230 cm. The total length of the model with 230 cm jib is 330 cm.

Here the crane is assembled with 150 cm tower and 230 cm jib:

29588765cs.jpg

29588796dh.jpg

29588776vm.jpg

29837251nc.jpg

29837241ay.jpg

The crane can be disassembled into the same number of small parts as the real crane. These parts have roughly the scale measurements.

 

Thanks to efferman´s turntable support ring the slewing ring is quite stable and rotates well (in the first video above the support ring was not attached yet, that is why the crane swings so much when it lifts or drops the load). The maximum capacity of the crane is approximately 400 grams in 2 fall-operation. But there is a second trolley and hook which allow an automatic change between 2 und 4 fall operation. The mechanism is the same as used for the real Liebherr fast erecting cranes und smaller EC-Bs.

29666788nr.jpg

29666801sm.jpg

29666818be.jpg

 

Edited by PistenBully 600

Share this post


Link to post
Share on other sites

I spent the last two months in creating a climbing unit for this crane. Real tower cranes use climbing units to climb up along growing buildings during construction.

The climbing unit lifts the complete upper part of the crane, including the crane head and counter jib. A hydraulic cylinder mounted at the climbing cage braces itself on a “K” shaped strut of the tower and presses the upper part of the crane upwards. This happens 5 times until there is enough space beneath the slewing ring to insert the next tower section.

Here is an animation that shows the system developed by Liebherr:

 

 

The climbing unit was the most difficult feature of this model. At first, with the crane in its smallest configuration with 150 cm jib, it has to lift a weight of 4.2 kilograms. The finished climbing unit has a weight of 1.8 Kilograms, so the total load that has to be lifted (including one tower section in front of the climbing unit) is around 6.5 kilograms. This load is lifted by two linear actuators, extended by strings with a tear strength of 35 kilograms. Any other string I tested has torn. The two cylinders are powered by one XL-Motor using a worm gear with 1:24 reduction. But anyway the motor has to struggle with the weight.

Fortunately I found out the right dimensions of the climbing frame so that it guides the tower very well without too much friction or backlash, which is very important for the climbing process. This is because the climbing unit has to absorb all kinds of imbalance of the upper crane, which could not be adjusted by the counterweight or the position of the trolley and hook. So the climbing cage has to be very stable, too. Especially when the climbing process itself is done and the next tower section can be inserted. At this time, the climbing cage touches the tower at a length of only 15 cm. All upcoming forces have to be absorbed by this small part of the cage.

But this is enough of writing – after all there was the final load capacity test with a load of 4.8 kilograms (6.7 kilograms including the climbing unit). And what shall I say? It worked! Here is a picture of the climbing cage lifting this weight:

30217525gd.jpg

 

After adding some details such as walkways and a small trolley powered by 2 micro motors for inserting the tower sections, the climbing unit was finished:

30217558fk.jpg

30217626zw.jpg

The lifting unit:

 30217638jc.jpg

30217604us.jpg

 

30217685wz.png

30217740zi.jpg

30217594ec.jpg

30217566nd.jpg

 

Here is a video of the climbing process:

 

And a video of the crane climbing back down. In real life this happens when the construction of skyscrapers is completed and the crane can be disassembled:

 

At the moment I am improving the model and I am reducing some weight in the upper structure.

The jib lost 200 grams at a length of 200 cm:

30351504rp.jpg

30351505oa.jpg

30351507pk.jpg

30351509pe.jpg

 

All in all this is a very cool project for me and I like the result. I hope you like it, too - feel free to comment.

Share this post


Link to post
Share on other sites
11 hours ago, PistenBully 600 said:

Thanks!

@suffocation the string is 0.15 mm fishing line. I don't have a link because I didn't buy it online.

@Aleh The crane is a LTM 11200 in 1:50 scale produced by NZG: http://www.nzg.de/liebherr-ltm11200-9-5396.html

 

 

Thanks! Your Libherr 250-EC is really amazing! True stuff for any Lego or building equipment exibition!!

Share this post


Link to post
Share on other sites

A big waow. And congratulations.

Probably one on the best model I've seen these days. I'm very surprised by the stability during movement, even with a load. Very great work.

Share this post


Link to post
Share on other sites

Thanks!

I spent the last days optimizing the jib by reducing some more weight and making it more straight. I will let you know when there are some more news about this model, but it's mostly finished.

Share this post


Link to post
Share on other sites

Hi, here are some pictures of the erection of the Liebherr 250 EC-B with 147 cm tower and 200 cm jib (in reality this are 26 m tower and 35 m jib, so it's a quite small configuration. The maximum tower heigth and jib length are 70 m).

Tower and crane head were already installed:

30543394zq.jpg

30543396ve.jpg

Then the counter jib was mounted:

30543398tt.jpg

Because of the weight of the counter jib, it tilted quite a little:

30543402yr.jpg

Then the jib and 2 counterweight blocks were attached:

30543408yz.jpg

After reeving the hook, the crane is ready for any lifting operation.

30543413qt.jpg

30543415dc.jpg


I hope you like this short report.

 

Share this post


Link to post
Share on other sites

Amazing MOC!! :) This is the most realistic Lego model of a tower crane so far that I have met! I can see You are a tower crane- and a ropeway fan too, just like I am. :) Cool!

Share this post


Link to post
Share on other sites

Oh wow, I don't think I've ever seen a Lego tower crane with a functional climbing frame before, and the automatic switching between falls of rope is brilliant. Keep up the great work.

 

do you think you could post an LDD file for the hook block with the auto switching? I'd really like to see how that mechanism works.

Edited by Saberwing40k

Share this post


Link to post
Share on other sites
On 10.11.2017 at 1:22 AM, Saberwing40k said:

Oh wow, I don't think I've ever seen a Lego tower crane with a functional climbing frame before, and the automatic switching between falls of rope is brilliant. Keep up the great work.

 

do you think you could post an LDD file for the hook block with the auto switching? I'd really like to see how that mechanism works.

Hi, At first sorry for the late answer. I didn't check this topic for too long.

I don't have a lxf of this mechanism yet. But here you can see a video of how it works at a real crane:

I just rebuilt this mechanism with Lego. I hope the video helps you. Otherwise let me know.

Share this post


Link to post
Share on other sites

There have been some updates to the crane this year and I want to show you these.

 

In april I assembled the crane outdoors with a jib length of 2 meters and an overall length of 3 meters. For the first time I assembled the crane with an overall heigth of 290 cm.

35574102vu.jpg

35574103ds.jpg

35574105dd.jpg

35574109di.jpg

35574110vc.jpg

35574112sk.jpg


 

Share this post


Link to post
Share on other sites

Since may I am optimizing and rebuilding the crane. First I built a new hook block an trolley. Their measurements fit to the scale measurements of the real crane. In addition they have less weight now, what is good for the crane performance.

Next I optimized the jib. This means that the connection points between the liftarms along the top of the jib and the technic bricks along the ground sides of the jib became smaller and less heavy by this. I also changed the profile and lattice work of some jib sections in order to make the jib more straight.

Befor this modification the maximum usable jib length was 200 cm. During a former test with a 230 cm long jib it bended quite a lot and the end of the jib hang quite down. But because of the mentioned improvements the "standard long jib" configuration for work and exibitions increased to 240 cm jib. With this lengt the jib is still perfectly straight and the crane needs less counterweigth than the early version with 230 cm jib. The new maximum jib length is 270 cm - as much as my Liebherr 280 EC-H with tower top and pendant bars has. But the jib of the 250 EC-B is even much more straight. So this modifications brought a hugh benefit to the size and performance of the crane.

In the next step I built a complete new crane head with the slewing ring and "tower top". The slewing ring is now 100% built of lego and the slewing speed was decreased using a 1:3 gearing before the worm gear which turns the turntable. This decreased the slewing speed to a very nice speed range from a fine-positioning slow speed up to a quite fast but good controlable and scale top speed.

Here are some pictures which show the crane after this first improvements at the ABSolutSteinchen exibition in june. The crane was assembled with 240 cm jib (340 cm total length) and a heigth of 211 cm. It worked a lot at during the exibition and it was a lot of fun operating it and sleving overhead the other exibitors :D

First a picture of the new crane head:

36045715vb.jpg

36045309zk.jpg

36045308pf.jpg

36045310kr.jpg

36045312vr.jpg

36045313yk.jpg

 

Here are three videos of the crane during the exibition:

 

 

 

Edited by PistenBully 600

Share this post


Link to post
Share on other sites

The next point to improve was the hook assembly for changing the number of falls of rope. The old mechanism worked quite fine but it was big, heavy and did not look the most realistic. So I rebuilt the trolley and hook block in order to make it look more realistic and to decrease the size. Also the changing operation is much more smoothe now.

36291198bx.jpg


 

Two fall of rope mode for light loads:

36291199wo.jpg

Four fall of rope mode for heavy loads:

36291203fm.jpg

Trolley in working position (red flaps point downwards) :

36291205no.jpg

Trolley in switching position (red flaps are pushed apart to indicate that the switching process is working properly and to indicate the end of the switching process - just like the real crane's mechanism:

36291206bl.jpg


 

And a video showing the switching process:

 

Share this post


Link to post
Share on other sites

During the last days I developed a new counter jib using the Lego Digital Designer. The aim was to make it more straight, to reduce the weight and to make it look much more like the real counter jib.

The new counter jib is build out of usual bricks and plates - instead of technic bricks - to create a much better look. Unfortunately the new jib is one part, both the old jib and the real counter jib consist of two parts which can be taken apart for more compact transport loads. But this was not possible for the new counter jib because I wanted it to be straight and in addition a possible connecting point would not be easy to realize with the new building technique.

The new hoisting winch drum has the scale measurements and is driven by a L-motor. The drum itself has an integrated planetary gear with 1:4 reduction to increase the load capacity of the crane.

During the next weeks I want to collect all the needed bricks to build the counter jib in real. I hope it will be as stabile and strong as needed.

I think the final design meets the real counterjib quite good - what do you think? Here is a picture of the real one for comparison (the upper crane);

 

Liebherr 250 EC-B 12 Litronic

source

the old counter jib:

36855049cr.png

The new version:

36891008cr.png

36891011bl.png

36891009bg.png

36891010dd.png

36891012vy.png

The real hoisting winch drum uses the old turntables. But these are no separate parts in LDD.

36918788of.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.