D3K

[MOC] Pneumatic Materials Handler/Excavator

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I've been playing around a lot with pneumatics lately, and want to show you one of my recent MOCs. This one has been made over the last week, from a smaller, more yellow prototype. It is fairly small (scaled to the tracks, as they are the size they are), and the width of the body is 15 studs, compared to 8043's 19.

Also, it's manual. No compressor or anything.

I'll go ahead and show it off in "Excavator mode" first :classic:

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As you can see, the range of movement is quite decent, and it folds up pretty nicely for a transport configuration. The boom is lifted by two of the old style long pneumatic cylinders, and the dipper and bucket are each controlled with one normal cylinder. There is a third pneumatic circuit going to the end of the boom, but it's not in use when it only has a normal excavator bucket mounted.

There is also a dozer blade on the chassis, operated by two small pneumatic cylinders.

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Next I have fitted the material handling claw, and as you can see this is where the extra pneumatic circuit comes in to play.

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The claw is operated with two small pneumatic cylinders.

An added feature present is many material handlers is a lifting operator's cab. This has been implemented with a normal pneumatic cylinder.

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Next up is a picture of the top of the superstructure, with the pneumatic lines and some detail of the cab lifting function

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Now, if you've made it this far. you might wonder where the pneumatic pump is ? :look: As I said, the model is afterall manual :wink:

Well, it is actually mounted horizontally inside the superstructure. The 2L black pin connector (on the right hand side of the grey "air filter") in the above picture is connected to it, and by pushing it forward, you pump air into the system.

Here is a picture from an early stage in the build that shows the principle:

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Also the valves are hidden on various places inside the superstructure.

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Well, that's it more or less, hope you guys like it. Like I said, this was put together fairly quickly, so there is definitely room for improvement both aestethically and build-wise (the inside is per now a mess of reinforcing and pneumatic tubing with not much system to it :blush:

Lastly, another picture with one of my other recent pneumatic MOCs (still a WIP):

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EDIT:

All pictures, as well as some others, can be found in a lot higher resolution in this Bricksafe folder

I have recently started using my aging DSLR again, so it might be worth a look if you want to see more details :thumbup:

Edited by D3K

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Wow! Great stuff! Compact and complex, I love things like this. Nice truck, btw :)

Edited by SilenWin

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Nice use of old cylinders! How do they compare to the new generation, any differences? Also how do you force the arm down?

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What a great build! It'd be great to see it in action with a video, if you ever get the chance.

Also, what about the truck? It seems that a little of lime light should be cast in it's direction :classic:

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Thanks, glad you like it! :classic: :classic:

Nice use of old cylinders! How do they compare to the new generation, any differences? Also how do you force the arm down?

I have five of these old cylinders, and they all act kind of differently :laugh: Some have a lot of friction, and some have little. One of them leaks a little, and one is broken. For this I chose the two with the least friction, so when I flip the valve, the boom freefalls as the air is released from the cylinders. In this setup, it can't be forced down, but I imagine the weight of the boom is enough to drive the bucket into most stuff people would dig with a Lego excavator. :wink:

What a great build! It'd be great to see it in action with a video, if you ever get the chance.

Also, what about the truck? It seems that a little of lime light should be cast in it's direction :classic:

I will make a video, and hopefully I'll get some digging action going as well.

The truck will be presented in due time, but several critical parts are currently tied up in yet another build I've been working on (have a lot of free time as of lately). The model has a couple of features that are not immediately apparent from these pictures :wink:

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Great looking excavator, the colours scheme is very pleasant and the functions are pretty sweet. Have you considered taking out the angled exhaust pipes and leaving only the black part that's used to pump the cylinder as the exhaust? Might make for a cleaner look.

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That is very nice. Love the white colour scheme. Looks really playable too.

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I love models full of pneumatics and this is no exception. Seems like all the tubing would be a tight squeeze

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Very nice model. I really like it. It looks like a perfect combination of size and features :classic:

Btw, if you ever decide to make an LDraw model, I'd love to (help) creating the pneumatic tubes.

I've recently started to use LDcad and I'd like to see how its own flexible-parts system works with such an amount of tubes :grin:

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That's a great model. Cool to see how you squeezed all that functionality in such a small space without sacrificing the looks. I'm also very curious about the truck; it looks great and the two models go exceptionally well together! Wonderful, I want to play with it :grin:

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Great looking excavator, the colours scheme is very pleasant and the functions are pretty sweet. Have you considered taking out the angled exhaust pipes and leaving only the black part that's used to pump the cylinder as the exhaust? Might make for a cleaner look.

Thanks! And no, I hadn't concidered that, but I do now :classic: However, the exhausts are actually pneumatic switches, so I'd have to use axle connectors instead.. I'll give it a try! :thumbup:

I love models full of pneumatics and this is no exception. Seems like all the tubing would be a tight squeeze

There is indeed tubing criss-crossing and going all over the place on the inside. The boom assembly is designed to be easily disconnected from the superstructure, so that tidies things up a bit, but like I mentioned, there isn't a lot of system to where the cables are routed inside the superstructure, right now they are just connected to the right places :blush:

Very nice model. I really like it. It looks like a perfect combination of size and features :classic:

Btw, if you ever decide to make an LDraw model, I'd love to (help) creating the pneumatic tubes.

I've recently started to use LDcad and I'd like to see how its own flexible-parts system works with such an amount of tubes :grin:

Thanks! And yes, I am planning to make an LDraw model of it, not sure if I'll take the time to step it and create sub assemblies though... If you would make the tubes for an otherwise finished model, that would be awesome! I haven't used LDcad, and LSynth hasn't worked properly on my computer, so I wouldn't be able to myself :thumbup: I'll give you notification when the LDR is completed!

Very nice excavator! Is it enough space for air tank in it?

Thanks! Yes, there definitely is.. somewhere.. with some minor repositioning of one of the valves :sweet: The reason I don't have one, is because of the old cylinders. Whenever you want to lower the boom, since the number two port on the boom lift valve isn't connected to anything, all the air in the system is vented, effectively making an air tankt pretty unnecessary :thumbdown: However, I plan to implement the new pneumatics being released later this year, and then I will definitely fit an air tank! :thumbup:

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I love that you have mixed the old and new cylinders! You could try using an old pneumatic distribution block to make it possible to force down the boom cylinders?

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I love that you have mixed the old and new cylinders! You could try using an old pneumatic distribution block to make it possible to force down the boom cylinders?

Thanks, glad you like it! :classic:

To get the retracting effect I would then need to have a separate circuit incorporating the old style pump as well, as the new and old types of pump work in different manners. The old one is in effect similar to the old cylinders, except it has a spring. So it is closed off. The new one lets air into the compression chamber (correct terminology?) when it moves up, which is then pumped into the system when it is pressed down again. The old system actually really sucks in the whole retracting action, as it is dependent on the negative pressure created from the spring in the pump as it moves up. Don't know how much sense this made, but I think Blakbird has a probably better explanation on his Technicopedia page concerning the updated pneumatics in 1989. :classic:

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It's a real beauty. Liking the truck too coz it looks like a small 8258 (wasn't able to get my hands on that)

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@legolijntje I have made an .mpd of the arm assembly that you can have a go at. It has six pneumatic tubes and two rigid hoses. You (and anyone else) can download the file here.

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EDIT:

Decided to give it a go, and it seems like a really neat tool!

The hoses show up in both LDview and LPub, so maybe I can actually do it myself! :classic:

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Edited by D3K

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2 D3K: Yes I've missed this problem with old cylinders. Maybe one extra valve will solve it.

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EDIT:

Decided to give it a go, and it seems like a really neat tool!

The hoses show up in both LDview and LPub, so maybe I can actually do it myself! :classic:

Did you use LDCad? It's quite nice, isn't it? :classic::thumbup:

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2 D3K: Yes I've missed this problem with old cylinders. Maybe one extra valve will solve it.

Yes, I suppose one could add another valve, to cut the old cylinders off from the rest of the system when they are to be lowered.. But I think I'll just wait for the new long cylinders to come along :classic:

Did you use LDCad? It's quite nice, isn't it? :classic::thumbup:

Yeah, it's brilliant! I've only used it to make the hoses yet though, the UI is kinda messy and has some annoying issues, but that's probably because I haven't used it before :blush: Much of it can probably be fixed in the settings, but so far so good.. I use LDcad to make the hoses, and then MLcad to fix everything else. From what I can see, it seems like the hoses and other flexible parts show up in MLcad as parts, so thay can be moved around order wise, for when one makes instructions?

Anyway, got the arm all hosed up:

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Pictures clickable for higher resolution :wink:

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[...]

Yeah, it's brilliant! I've only used it to make the hoses yet though, the UI is kinda messy and has some annoying issues, but that's probably because I haven't used it before :blush: Much of it can probably be fixed in the settings, but so far so good.. I use LDcad to make the hoses, and then MLcad to fix everything else. From what I can see, it seems like the hoses and other flexible parts show up in MLcad as parts, so thay can be moved around order wise, for when one makes instructions?

[...]

About the UI, it takes some time getting used to, But, when you're used to it, it works quite well. I believe Roland (the author) is working on some UI improvements/changes in the 1.5 update.

If you add a pneumatic tube and you choose the ".mpd submodel" option, it becomes a submodel, just like all other submodels. So, in the main model, you can move the hoses around, as you said.

And yes, you can easily use them in instructions. I did the same with PF wires and flex axles in the Alfa Romeo instructions. You only need to add some LPub meta commands so it won't generate building steps for the flexible parts (and optionally you can use some LPub commands to show the submodel in the PLI as a part*).

But, we're maybe getting a bit off topic here. :wink:

There's an LDCad topic if you have more questions about LDCad. And, I believe Roland reads there as well.

*What I mean with that is, for example the flex-axles in the Alfa Romeo. They are weirdly shaped submodels. I can let LPub ignore them or I can let LPub show them in the PLI. But, they would look still weridly shaped in the PLI. A few LPub commands can replace the submodel with another part in the PLI, so it looks like a straight flex axle in the PLI. You can do the same with PF motors, pneumatic tubes, etc etc. I have the feeling this is the worst explanation ever :grin:


Btw, another tip: if you use LDCad's pneumatic cylinder template instead of the simple LDraw part, you can easily move the piston in and out of the cylinder.

It makes your render a little better :wink:

Edited by legolijntje

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Thanks for the help! Yes, I did try to read up a bit, and saw some of Roland's videos on youtube, and off I went! Found the topic you referred to as well, and it was quite helpful.

Regarding the cylinder length; YESS!! That is awesome news, can't understand why they are not modelled as two parts for MLcad (like the LAs are). This will be really helpful indeed, especially for models where the cylinders physically can't retract or extend 100% (like the dipper cylinder in this model, it is only able to retract perhaps 97%).

Again, thanks a lot!

Now to try to make sense of the hoses havoc inside of the model! :sweet::wacko:

EDIT:

yay!

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Edited by D3K

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2 D3K: Yes I've missed this problem with old cylinders. Maybe one extra valve will solve it.

You don't need an extra valve to let gravity do it's work. Just switch the inlet and outlet on the valve. Cylinders should go to the center and pump left or right. If you want a slow descent just put a short piece of tube on the unused valve outlet, plug the end with an antenna and punch a hole in the tube with a needle. This will make the air flow out of the cylinders nice and easy. No boom crashing to the ground.

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You don't need an extra valve to let gravity do it's work. Just switch the inlet and outlet on the valve. Cylinders should go to the center and pump left or right. If you want a slow descent just put a short piece of tube on the unused valve outlet, plug the end with an antenna and punch a hole in the tube with a needle. This will make the air flow out of the cylinders nice and easy. No boom crashing to the ground.

Not a bad idea that, will definitely give it a try! :thumbup:

In the mean time, I have been busy with MLcad and LDcad, and have now made a stepped LDraw file for the entire superstructure with arm, including the pneumatics! Once I've made the undercarriage/chassis, I will make it available for anyone to do with as they please. I will not make .pdf instructions due to the time involved, but anyone wanting to build it should be able to do so quite easily (for example going through it step by step in LDcad). I really like LDcad more and more, it has some pretty genious functions! Just one thing I noticed: When you make the pneumatic hoses, you start with a short length, and then manipulate it into the shape/length you want. With the "snap to parts" function on, the ends easily snap onto outlets/inlets of solid pneumatic parts. But the true genious is this: When you select a completed pneumatic hose, it gives you the exact length of it in millimetres! Simply brilliant!

Anyway, here are a couple more renders of the completed assembly, as well as a colour coded pneumatic chart (again clickable for higher resolution):

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EDIT:

Cabin lift

Bucket

Dipper

Auxilliary

Boom lift

Pump->valves

Edited by D3K

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