[WIP] Crawler Crane

[gvo25]

Dear all,

While the news went out that lego was designing a new liebherr crawler crane, I decided immediately to build my own version, with 6 PU motors, 3 L ones and 3 XL's. the boom will have 9X9 dimension. The body uses the turntable of the 42082 rtc. Untill now the body is more or less finished, but it needs still tweaking and further adjusting while the build advances. Now I'm waiting for parts for the boom including some weights for the hook.

Here are some photos, including 1 with the previous 42042 crawler crane

This is an early work in progress, the cogs are better reinforced and everything is working smoothly now

Here the main body is more or less finished, including cabin and ballast (2 times 9 big panels)

Here is an image from behind, I used the linear actuators for support of the ballast, and to connect the ballast directly to the axle of the pulleys. I thought it looked very cool a construction like this. The batteries of the batterybox can be easily replaced (no screws). You can also see part of the drivetrain, maybe this has to be geared down a little bit more, the crane runs still a bit too fast.

And last but not least a photo for compairison of scale.

I hope you liked it for now, as always comments or questions are always welcome

 

[technicfanatic]

Looking great! The battery box looks to be riding very close to the ground.

[gvo25]

3 minutes ago, technicfanatic said:

Looking great! The battery box looks to be riding very close to the ground.

Yes it is exactly the height of one liftarm

[whitepen]

This looks awesome! Looking forward to more progress, maybe i will build a crane!

[Aleh]

What does the black gear on the side of the track used for?

[Gray Gear]

What are the two shocks on the boom for?

[gvo25]

2 hours ago, Aleh said:

What does the black gear on the side of the track used for?

It is the tensioner of the track, each track has this gear rack inside (I don't know how the part is called). so the track has the optimal tension

1 hour ago, Gray Gear said:

What are the two shocks on the boom for?

It's to be sure that the main boom goes down when it's lifted in its highest position. The shock absorbers help gravity a little bit to lower the boom. I saw that liebherr cranes have these types of struts too, this is my version.

[Gray Gear]

@gvo25 Thanks for the explanation, I should have thought of that myself tbh

[Aleh]

9 hours ago, gvo25 said:

It's to be sure that the main boom goes down when it's lifted in its highest position. The shock absorbers help gravity a little bit to lower the boom. I saw that liebherr cranes have these types of struts too, this is my version.

If I'm not wrong real model uses hydroylic cylinder for every boom. I/m I right? Your solutionn is cool, of course!
And about the track tension- this is your decision and not taken from the real model, right?

[gvo25]

1 hour ago, Aleh said:

If I'm not wrong real model uses hydroylic cylinder for every boom. I/m I right? Your solutionn is cool, of course!
And about the track tension- this is your decision and not taken from the real model, right?

The track tensioning system is indeed my solution, I didn't want to use springs as I find it a very bulky and piece-heavy system.

It looks like they are hydraulic shocks, the lego black shock absorbers are very good to make large rods like the ones on my crane.

[gvo25]

Hello all,

So at last my bricklink orders arrived and I could finish the base crane with a slightly modified A-frame and a main boom. The A-frame is a lot stronger now with less torsion. The wire is now double reeved on the same winch to have a better distribution of the load.

The main hoisting hook is reeved 3 times, and inside the main pulley block there is a ballast weight of 30g. There's also a secondary lego metal hook which is double reeved. The construction for the secondary hook can be easily dissassembled.

(sorry for the blurred picture)

At last a photo with the cat for scale, now the total height of the crane is 110cm with the boom on it's max position

Coming soon will be a video to demonstrate all the functions

Next on the list will be a luffing jib. I also will install a 4th winch situated inside the main boom. Maybe I also redesign the undercarriage because under load the undercarriage flexes a lot. Also I would like to make the tracks longer.

[Gray Gear]

Lookoing good! Only thing I don't like is the height of the tracks. Using the smaller drive wheels and a loger trackbase would be more visually pleasing for me.

[technicfanatic]

This is very impressive. I'm guessing about $1000 worth of parts? What is the part that you use to make the "wires" that are holding up the boom? The axle like parts that are held together by the 41677s? Thanks.

[gvo25]

4 minutes ago, technicfanatic said:

This is very impressive. I'm guessing about $1000 worth of parts? What is the part that you use to make the "wires" that are holding up the boom? The axle like parts that are held together by the 41677s? Thanks.

The part is called 'Technic link 1X16' in Light bluish grey, bricklink nr. is 2637, lego technic ID is 4211556

9 minutes ago, Gray Gear said:

Lookoing good! Only thing I don't like is the height of the tracks. Using the smaller drive wheels and a loger trackbase would be more visually pleasing for me.

I fear the smaller drive wheels won't fit the scale of the crane body very well, but a modification of the undercarriage is on my to do list

[technicfanatic]

Cool, thank you. In a "real" crane would these be steel cables under tension? Could you have used thread instead of these links? Or might that cause too much wobbling or indeed, do you need these links to work both in tension and compression?

[gvo25]

3 minutes ago, technicfanatic said:

Cool, thank you. In a "real" crane would these be steel cables under tension? Could you have used thread instead of these links? Or might that cause too much wobbling or indeed, do you need these links to work both in tension and compression?

In the real cran they use rods (in the liebherr cranes anyway), my guess would be that wires would stretch too much under load, and you would have to use real big diameter cables. I think rods are lighter to use then cables. Compression is no issue because everything is under suspension.

[Saberwing40k]

I've seen it done both ways. Some cranes use solid pendant bars, while others use steel cables. I'm not entirely clear on if one is better than the other, or if one works better under some circumstances. One thing I have noticed is that often times it is so called duty cycle cranes like the Liebherr HS 855 tend to have wire rope pendants, but not all machines of this type do. Duty Cycle cranes are often used as draglines, or with various types of foundation equipment, so that might explain why those sometimes have wire rope pendants.

[suffocation]

Looks really good and I love the 42055-ish colour scheme

The only - very minor - tweak I'd suggest would be to extend the tracks by half a dozen studs or so.

[Aleh]

The main photo with the Sir cat is cool!

I've noticed that you implemented double winch to the A-frame, like the real crane - high attention to details, greaat!

 

[Bartybum]

On 3/22/2022 at 6:51 AM, gvo25 said:

The part is called 'Technic link 1X16' in Light bluish grey, bricklink nr. is 2637, lego technic ID is 4211556

I fear the smaller drive wheels won't fit the scale of the crane body very well, but a modification of the undercarriage is on my to do list

I think you should try it out. You'll get more torque with smaller wheels anyway so the performance will improve. Other than that I do love a good crawler crane MOC, so great job

[Johnny1360]

When I first saw this great crane moc a couple of weeks ago, I thought the boom looked a little out of place on this model. Then today I saw a real life crane with a very similar boom. It was being used to lift huge, obviously extremely heavy concrete slabs for a commercial building so I have to say, well done, looks great.

[frechettemj]

Here's what I've got for tracks. They're geared way down, so it'll drive and turn on carpet. 

20220325_223415 by Matthew Frechette, on Flickr

Edited March 26, 2022 by frechettemj

[Aleh]

But this is a bigger scale model I assume

[frechettemj]

13 hours ago, Aleh said:

But this is a bigger scale model I assume

Indeed. Just offering an example. 

[Aleh]

10 hours ago, frechettemj said:

Indeed. Just offering an example. 

Ah, got it. Obviously your tracks have the form like the original real model, not an oval.