[TC8] Folding Crane

[Erik Leppen]

TC8 Folding Crane (not yet finished)

I think it's about time to show what I have been secretly working on in the past weeks. It's not done yet, but it's getting there and I feel that this time, things might just work out.

As you can see, it's not finished. The biggest question mark right now for me is, where to put the winch that will unfold the jib. There's no room anywhere! :D

Of course, I'll be showing the unfolded state later (when everything works).

So, what does it do? The carrier has two functions:

1. steering on all axles, driven from a gear on the back. Central axle has half the angle of the other two.

2. outriggers, all connected, driven from a gear on the back. Outriggers are the same system as those in 8460.

There's no engine - no room.

Slewing the superstructure is the same mechanism as 8421 - manual.

The superstructure has two winches.

1. lifting the main boom

2. extending the main boom

Both are worm-driven, to prevent backdriving.

A third winch has to be fitted somewhere to unfold the jib. This will probably end up somewhere on the boom - there's no space on the supersturcutre to add a third worm-driven winch. Unless, maybe, I sacrifice the paneling.

Last jib section has to be put on by hand. The actual crane winch and hook are also still to do. Might be that I make the last jib section a bit shorter to keep things in proportion a bit. Also, the controls for the crane winch might also be simple and close to the function itself. Controlling everything from the base is simply not possible. Sets do this too, so I don't see it as a problem.

Building a decently-working folding crane is high on my wish-list for quite some time (think years), so I really hope I can get everything to work this time.

I all goes well, I might do instructions (but without the strings). I keep a digital file, which tells me I'm at about 1400 parts right now.

Any tips are welcome, especially as to where to put that winch :P

[efferman]

Cute!

why not unfold the jib while extending the mainboom? So you would not need a winch to unfold the jib.

[MajklSpajkl]

Looks great, good to see a model on the smaller side - I hope you get it done, no Idea for the winch though.

[THERIZE]

it looks nice! how did you make the all axle steering? could you show a picture of that?

[Erik Leppen]

Cute!

why not unfold the jib while extending the mainboom? So you would not need a winch to unfold the jib.

Thanks :)

Yeah, I might try that. Although it would mean more stress on the extension part, and less flexibility. But it might be the best option indeed.

Looks great, good to see a model on the smaller side - I hope you get it done, no Idea for the winch though.

Thanks. Yes, I like smaller models myself better too. I think with these type of cranes this is the best scale. Any smaller and it's not wide enough to fit things in, any bigger and things become really heavy really quick. That's why it's only three axles :)

it looks nice! how did you make the all axle steering? could you show a picture of that?

I made a cut-out of the digital file. The steering is linkage-based.

Interestingly I spotted a few errors in the digital file when making this, so thanks :)

[TheItalianBrick]

Big battle between this and effe's one!! Really cute so far…clever steering system indeed!

Maybe a simple worm gear on top of the main boom to fold the last piece of boom.

Otherwise you need to lose the extending section of the main boom and use a lever to unfold the all crane in one step!

Looking forward to the final model Erik!

[2LegoOrNot2Lego...]

Nice build so far!

[Lakop]

Great crane and good size. I'm working on my own moc here, a bit here and there, the hardest thing i've started in all my lego years. I'm sure you will find a solution to your remaining issues.

Good luck

H

[Erik Leppen]

A small update:

why not unfold the jib while extending the mainboom? So you would not need a winch to unfold the jib.

Yeah, I might try that. Although it would mean more stress on the extension part, and less flexibility. But it might be the best option indeed.

I tried this now, and it works like a charm. I have the rope running back and forth over the boom so the amount of rope needed is doubled, and it matches almost exactly.

No picture yet, because it's hidden from sight anyway. When everything is done, I will post pictures in unfolded state.

This means there's but one hurdle remaining to overcome, which is a trolley that will slide over the boom and contain the winch and hook.

I made a first version, but it's too large for transport. So I need to devise a small and compact trolley with a hook that's heavy enough to keep the string taut.

Also I made the final jib section 10 studs shorter. It's better in proportion now. It will still be mounted by hand though.

[rhplus]

great compact crane, I can't wait to see more pictures and it looks like my favourite good old 8460

[BusterHaus]

Looking forward to more pictures. I like the mix of studded and studless.

[Erik Leppen]

It's picture time!

It's really 99.5% done now. Only the hook unit has to be remade (more compact), so it can actually be carried for transport. I have to say though that operating the thing is quite a challenge. The strings tend to get tangled up, but I don't think this can be prevented.

Also, I used an external motor to drive the functions. I just put some axles and small beams connected to an M motor, so that it grabs into the knob wheels. Everything could be done manually, but that would take ages. Putting any kind of motor anywhere in the model itself is totally infeasible.

Also, when fully extended, it's rather... wobbly. Guess that's also inevitable, given how everything rests on a single turntable, and the carrier has hardly any space to make it rigid enough. So I don't dare lifting anything with it. Fortunately that's not the point of the competition :) That fact it works at all is quite a feat :D But doing a neat video will be quite a challenge :)

Edited March 5, 2016 by Erik Leppen

[JamesJT]

I think this is brilliant. The transformation is so good it could have been in TC7. Excellent work.

[A Gallifreyan Cat]

That looks really cool! Can't wait to see the 100% done version.

[Lipko]

This is my favourite in the contest. It's cute as a puppy.

[Samer]

I love this

[Rockbrick]

as always the models that I want to build as soon as I see them are the ones that get most of my votes

this is no exception

[TinkerBrick]

Love it!

[MaxSupercars]

Erik,

very good work... I like it very much. Nice how you have integrated all the function in this smaller scale. Nice details.. White color is also pretty. I'm looking forward for video... :)

Max...

Edited October 28, 2015 by MaxSupercars

[2LegoOrNot2Lego...]

Excellent!!!

[Sir Wolf]

I love this crane. It's simply stunning! How did you thread the hook cable? Does it go on the inside of the boom?

[Sylvian]

Impressive... much wow for such scale..

[Erik Leppen]

Thanks for all the replies, folks! :D

It's now officially entered, with video. Check the entry post :)

The transformation is so good it could have been in TC7.

Haha, thanks! Even the color scheme would fit :D

How did you thread the hook cable? Does it go on the inside of the boom?

Nothing special, alas. It's running directly from a winch on the trolley.

Edited November 1, 2015 by Erik Leppen

[Sir Wolf]

Nothing special, alas. It's running directly from a winch on the trolley.

Ah, that explains why I can't see the cable :P

I saw the video and I was impressed with the self-righting mechanism, very clever, well done! I also like your battery-powered hand-crank! Now that's clever! I think I'll build one for myself, to use with something. I just like the idea a lot.

[Erik Leppen]

I had a huge update for my website recently, and I also collected all my building instructions. And there's one of the folding crane! Although it doesn't include the strings, all the parts that are in contact with strings are colored purple for easy recognizability.

Download building instructions for Folding crane (from my website, erikleppen.nl).

Use this image for all the strings.

Also, see the model on my own website.