Ivan_M

[MOC]Truck with concrete pump - PF/pneu - 1 motor/5 functions

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Posted (edited)

Let me introduce my latest build:

Truck with concrete pump

Introduction

I got the inspiration for this kind of truck very long ago from this spectacular build from Waler: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=558238 . It was one of the first builds I saw when my dark age ended and I kept returning to it ever since. I knew I had to build my own when the time is right. I tried it once already (not published) in smaller scale 3 years ago but I wasn't skilled enough, the scale was wrong and I lacked the parts. I hope it is better this time. I also knew that I want to build it with very different features, Waller's truck if fully RC and I have found out that I prefer single motor and gearbox and steering and drive.

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Features & build

The list of features I wanted to implement were clear from the begining - full suspension, one motor for 6 functions, 3-section pneumatic arm, gearbox with two way switches and modular build. I wanted similar build/experience like Arocs so I have borrowed few features from it, most important is the way how the 3 modules (front axles with cabin and "crane", central gearbox, rear axles) are connected together. So I took the size of the gear box and its attachment points from Arocs and made my own one within the limits. Later I had to drop the 6th output that was supposed to drive some sort of lever ("pump") inside of the hopper because of complexity. The first iteration of the gearbox was quite fine, but it struggled when the long outriggers were hood on it because I have used clutch gear before the whole gearbox. That was major flaw so I had rebuild it again (almost) from scratch and even managed to add second penumatic pump to it. Each function is proteced either by white clutch gear, rubber band or LA clutch. The gearbox is powered by one L-motor which is powerfull enough to drive everything.

32903207377_090918752c_c.jpgConcrete pump gearbox

There are two switches on either side between the axles, on right there is switch for spreading outriggers and extending front ones, on left there is switch for lowering them and for pneumatic pump. Switch for arm rotation is under the turntable. The X-style outriggeres are as close to each other as possible. The problem is that the gears for the 4 mLA that spread outriggers have to turn in opposite direction on left/right side AND in opposite direction on front/rear side as well. You can probably see more from picture above.

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Rear axles are build in similar way like on arocs, the difference is that the springs are serured much better and there is build-in 1:3 reduction. Front axles are live axles with ackerman geometry and different steering angle. I'm really happy how they turned out, the spring is mounted to lower suspension arm so I was left with more space on chasis. The steering angle is very high at the cost of force required to steer. It is necessary to drive by one hand and steer by other one, the model is very heavy and steering at place is not very convenient. Rear axles are connected to V8 engine under the cabin.

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The cabin can tilt to reveal engine. there are two seats (of course in blue), dahsboard, gear stick and two pedals inside. I have also added screen wipers and all mirrors.

Arm is 3 sections. This was real science to make it as long as possible and light so the pistons can lift it. I have moved the pistons that operate 2nd and third section to opposite direction of the arm. This prooved very effective as it allowed me to make both sections at least 10 studs longer. I also wanted tubbing as nice as possible and thick tube for concrete as well.

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Full gallery:

https://flic.kr/s/aHskUypnbW

Video

Instructions

Yea, they are on the way :classic:

 

Edited by Ivan_M

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I like it. especially how You made that concrete tubing.

Does those plates (4L, 3L) really hold connection? Especially at the connection to pneumatic cylinder "axle" end?

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2 minutes ago, Jurss said:

I like it. especially how You made that concrete tubing.

Does those plates (4L, 3L) really hold connection? Especially at the connection to pneumatic cylinder "axle" end?

Thank you, the availablility of those 90° round tubes were the reason I started this project, they look splendid. Do you mean plates holding beams? It is very sturdy connection, to the point where 6L plate is too much to disassemble without big force

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Brilliant work! And you're a true legend for sharing instructions to this behemoth! I love the little detail of using a chain for the cabin tilt mechanism limiter. 

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I liked a lot and I recogniced the music from the begining :laugh: , I used the same in my Komatsu.

Spoiler

 

 

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Great build. We had one of these towering over our house yesterday pumping concrete to a neighbours property.

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Fantastic looking MOC:wub: It almost looks like a real set (only the connection with plates in the beam would never be made by LEGO, but then again, they would just make a special part for this connection). I really like the wealth of features, the complicated gearbox and the colourscheme. And knowing the quality of your instructions I am sure they will be as good as this model.

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I really like your MOC's you make.

That boom arm stays so straight when when fully extended it looks fantastic with such minimalist design.

the pneumatic switches look a little hard to get to perhaps :laugh: but didn't look like too much difficulty in the Video.

so many functions in the one motor is splendid. that gearbox makes my brain hurt.

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Posted (edited)

Thanks everyone for your kind words.

21 minutes ago, MangaNOID said:

the pneumatic switches look a little hard to get to perhaps :laugh: but didn't look like too much difficulty in the Video.

it is quite fine, the two switches for lower sections are on sides so they are very easy to reach, only the switch for 3rd section is more difficult to reach. I wanted them above the turntable because in that way only one pneumatic tube goes through it and rotation is not very limited, it can even perform 360° turn without blocking it

\\edit: I'm working on 3D model and once it is complete I will post colored details about all functions

Edited by Ivan_M

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Fantastic! Superb idea to move pistons to the begining of each section of the arm. I kinda envy you as I always wanted to try this one, but never got the balls to tackle the problems of making it. Well done again!

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