Inspiration for new models: Massive mining truck, amphibious excavator

[grindinggears]

Hi everyone,

I found a site that seems to be a virtual exhibition for construction equipment and other heavy vehicles.

Here is a link to the construction equipment section: http://www.directindustry.com/cat/equipment-construction-civil-engineering-mining-AR.html

There are two vehicles I want to highlight because I think they are excellent inspirations for builders looking for new ideas:

First a mining truck that takes a completely different approach on hauling things than the big two-axle trucks.

Each axle unit has two wheels attached to an oscillating sub-axle. The whole unit can be turned for steering and it is suspended and driven.

The dumping bed is lifted by hydraulic pistons attached to a special leverage. That one looks really useful!

The second model is an amphibious excavator (don't miss the video!). I have never seen something like this. Neither in reality nor in lego.

We definitely need more weird contraptions and lego provides us with the advantage of building them at low cost.

I hope someone got a 'click!' and maybe is able to build the axle unit (I tried but didn't get a compact solution) or even the whole mining truck. Or just browse a little on the page and look for new inspiration.

[dhc6twinotter]

Wow...that dump truck is very cool! That would be a really fun project. I'm going to add this to my list of projects, and I may do this as my next project. Very cool.

The ETF website also has some other interesting vehehicles, like the self loaders and haul trains.

Thanks for the links, grindinggears!

[allanp]

Imagine that dumper truck with 20 unimog wheels! Just the excuse I need to buy 5 unimogs

[dhc6twinotter]

Imagine that dumper truck with 20 unimog wheels! Just the excuse I need to buy 5 unimogs

LOL....exactly what I was thinking.

[Brickend]

I've tried to make the mining truck previously - ended up buying 8 turntables but failed due the implementation of a purely mechanical solution to the drive train.

The problem was that I wanted drive, steering and suspension. The sub axle must be central to the turntable, or it will not turn without massive resistance. Adding differentials was also out due to the scale of the wheels (62.4x20). When the sub axle is central, suspension with drive is very difficult without some sort of splined shaft. Unimog sized wheels would offer the chance to add a motor to each sub axle and maintain scale,thus making everything much simpler, but I find that idea quite boring, even if it is closer in principle to the transmission of the real machine.

[legodac]

I've tried to make the mining truck previously - ended up buying 8 turntables but failed due the implementation of a purely mechanical solution to the drive train.

The problem was that I wanted drive, steering and suspension. The sub axle must be central to the turntable, or it will not turn without massive resistance. Adding differentials was also out due to the scale of the wheels (62.4x20). When the sub axle is central, suspension with drive is very difficult without some sort of splined shaft. Unimog sized wheels would offer the chance to add a motor to each sub axle and maintain scale,thus making everything much simpler, but I find that idea quite boring, even if it is closer in principle to the transmission of the real machine.

Wow, what a place my friend has lead me to, my only wish at the moment is that I would be capable of completing my profile without getting a migrane, cool site eh, I hope we'll share soon. Btw, sub axles are erelevant, when taking stills.

[ManitobaMoe]

Where i am from, it is commonly known as a amphibex ice breaker. They are getting more common in colder climates that need to break up river/lake ice to allow for better flow in spring. I know they look weird, but they are actually very effective at what they do

The second model is an amphibious excavator (don't miss the video!). I have never seen something like this. Neither in reality nor in lego.

We definitely need more weird contraptions and lego provides us with the advantage of building them at low cost.

I hope someone got a 'click!' and maybe is able to build the axle unit (I tried but didn't get a compact solution) or even the whole mining truck. Or just browse a little on the page and look for new inspiration.

Edited June 26, 2011 by ManitobaMoe

[allanp]

Just a quick preliminary sketch for the sub axle. Not finished, but I really should get to bed, gettin up in the early hours for work every morning is a b*****d!

Edited June 26, 2011 by allanp

[Brickend]

Other issues I forgot to mention, is that if the axle assembly is too wide, or too deep, it may foul the tyres of the nearest bogie in the turns - assuming that the outer bogie turns at different angle to it's neighbour when in conventional steering mode. You can space the assemblies out to eradicate this, but in doing so may ruin the overall appearance of the vehicle.

The above images do look interesting - I never went above the aforementioned 62.4 tyres, with a 3 stud wide sub axle (no diff) because the vehicle was already massive. With 24x43 or larger you may get it to work, but again, if the tyres are too wide (i.e balloon), I fear the fouling issue may still arise.

You will also need to work out, when switching between crab and conventional steering, if you have to reverse the drive to the rear of the vehicle depending on the drive layout.

An additional method that I tried, was to suspend the turntable on a parallel link - it made the drive situation a lot easier, but complicated the steering, the advantage is that the drive needs to be a lot stronger than the steering.

[dhc6twinotter]

These trucks have the ability to crab?

allanp, that looks like a very nice, compact drive system.

[Brickend]

These trucks have the ability to crab?

allanp, that looks like a very nice, compact drive system.

My understanding of the literature is that they can't do a 90 degree crab, but they can crab at angles less than that - they don't have the burden of mechanics going through the turntables.

Edited June 26, 2011 by Brickend

[allanp]

The version I posted would crab anywhere you like! However it's large scale would be better suited to the unimog wheels, which would be awesome!!!!

[Cy-Gor]

Just a quick preliminary sketch for the sub axle. Not finished, but I really should get to bed, gettin up in the early hours for work every morning is a b*****d!

here is what i came up with today

[dhc6twinotter]

I need to figure out how to use that software you guys have.

I'm debating whether or not I want to tackle this project. It sounds like a fun project, but I don't know that I can justify buying 16 Unimog tires for one project.

[Erik Leppen]

here is what i came up with today

Posted image

This won't work. Because of the way you attached the shock absorbers the unit consisting of the 5 x 7 frames can't swing sideways. Exchange the two pins by just one to solve this. Also, attach them to the middle 5 x 7 frame and the other two frames can be removed.

[allanp]

I need to figure out how to use that software you guys have.

I'm debating whether or not I want to tackle this project. It sounds like a fun project, but I don't know that I can justify buying 16 Unimog tires for one project.

I'm using MLcad, Cy-Gor is isung LDD (lego digital designer) which is the easier of the two to set up and is available as a free download from lego.

It would indeed be a fun project which I am also debating although models of this size are usually not my style (sets that actually could be sold as official sets is more my thing). Fisrt I would need to be sure that the whole thing is possible in a design, functionality and complexity i'm happy with before buying any parts.

Maybe the design could be a joint poject between lots of us!

Edited June 28, 2011 by allanp

[Cy-Gor]

i changed it up a bit and here is what i have so far for drivetrain

[Brickend]

Woah! Massive.

That design kind of eats into where the load space should be. A 'blunt force' approach to giving it motive power.

I stopped working on this when it wouldn't work at 62.4 tyre scale because I realised it would require a stupid amount of motive power to move and steer. My preference is also for the Lego official sets scale; as things get bigger, they can get cruder and the strength of the Lego itself doesn't proportionally increase, the structures become larger to even support themselves.

[Cy-Gor]

i havent messed with this level of technic so some of the details might be missing.

would 10 smaller motors be enough? or should it be done with larger motors?

My current design is more of a proof of concept rather than a good working design. it is likely that i could move the servos around and gear up the motors to make it take up less space.

A problem i am running into with LDD is that its hard to judge clearances with this type of assembly so the main chassis will be hard to design. I am trying to make it have a full 360* rotation for the hubs to allow crabbing in any direction.

I will probably work on the chassis tomorrow.

[TheHammer]

I think this is a great idea for a project, i may have to build one for myself. I was thinking of using pneumatics for the suspension though. Do you mind if i borrow from your initial prototypes a little?

Also quick question, how do you get the 5x7 lift arm box to display in LDD?

[Brickend]

By having a motor on each axle, when the model is in conventional steering mode, all of the motors will be fighting each other, especially on a model of this scale.

I know the real thing has a motor on each axle, but then it would also have proportional speed control for each unit.

I think the best solution is to connect the left and right side axle assemblies into pairs, with a differential, and place the (5) drive motors in the centre. There would still be issues with competeing motor speeds from the front to the back of the model, but not side to side.

The real machine has a structural channel running down the centre, underneath the load area. This would appear to be a good place to position the motors and also create the structure to support the axle assemblies without compromising the load space.

[LLeveik]

Greetings,

I tried some setups, too.

This is what I was able to create today.

I'm not satisfied with it, but I woul like to share it with you. :)

I thought that with this setup shock absorbers are nonrelevant, correct me if I'm wrong!

http://imageshack.us/photo/my-images/846/pic1ac.jpg/

http://imageshack.us/photo/my-images/651/pic2io.jpg/

LLeveik

[allanp]

That looks cool, i'm glad you are using a diffencial in the axle otherwise steering would be difficult for the motor. I placed a red shock absorber in my original design to mimic the red cylinder pictured on the real thing. I believe they are indeed relevant for the real thing in order to not only spread the weight equally between pairs of wheels, but between all wheels. They may not be crucial for this model though it would be nice to replicate it.

[dhc6twinotter]

It appears that the middle set of wheels are not driven by the motor.

http://etftrucks.nl.vedor.com/Innovations/Tire-cost-savings/

(scroll down a bit--sorry, for some reason the forum isn't letting me post a picture with a jpg file extension )

Of course having all the wheels driven would be awesome, but it may be cheaper and/or easier to build the model with just 16 wheel drive. It would be more realistic as well. Something else to ponder.

Edited June 30, 2011 by dhc6twinotter

[Moz]

It appears that the middle set of wheels are not driven by the motor.

I think they are all motorised, the middle set are just not powered up. They talk about swapping wheel groups in and out, so it seems likely to me that there's only one type of wheel group, the powered one. I also read it as having two motors per unit, and the two sets of power cables in the images support that. This quote on the economics page:

ETF designed a diagnosis and performance test bench to achieve just that. The bench supports one full ‘wheel group’ comprising the steering turntable, swinging arm suspension, wheel motors and reduction gearbox.

Note the plural "motors".

Of course, in Lego it's hard enough to build a planetary gear system, let alone one with a motor inside it.

But this is an intriguing truck to look at. I wonder if it drives the way the 4wd/4ws telehandlers do - those are quite fun to drive, especially offroad. But given the size I suspect it's kinda boring -scaled up vehicles tend to be structurally weak and have low power to weight ratios.

Also, the way the tipping bed works looks quite cool. It seems to rotate the whole thing on a turntable, including the tipping mechanism. So it's not a conventional side tip unit, it's a rear tip unit that pivots. I suspect you'll want some supporting wheels under that to make it rotate easily and not break the turntable.