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Lipko   

Here's my entry to the Pneumatic Contest:

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The goal was to build a playable, sturdy model with a nice look.

Pneumatic features:
-backhoe bucket curl
-backhoe boom elevation
-backhoe dipper/stick in-out
-backhoe boom swing
-stabilizers
-loader boom elevation
-loader bucket curl

Other features:
-four-wheel steering with Hand of God and working cockpit steering-wheel
-pendular front axle
-rotating seat
-opening bonnet

The model is not based on a particular machine and it's made in the style that's more common in the USA than is Europe: the backhoe boom is centered and fixed (no sideways movement), but the stabilizers have wider base.

Controlling:
The pneumatic switches are placed on the sides of the model. They are easy to reach and to operate carefully, but hidden enough not to be visually distracting. There are two separate circuits on each sides, so two functions can be operated at a time with two hands without the functions affecting each other.
The functions are grouped together in a convenient way for a right-handed person. Backhoe: left hand for swinging and dipper elevation, and right hand for boom elevation and bucket curl. Loader: left hand for boom elevation and right hand for bucket operation.

The model is big enough to hide the tubes so the cockpit is not crammed with tubes.

Pneumatic power source:
A Power Functions medium motor driving two pumps for the two circuits. I decided to use a compressor instead of a manual pump for one main reason: Operation is much more convenient with two hands. But two hand operation requires two separate circuits because operating two cylinders with one circuit means that the cylinder with the higher load won't move until the cylinder with the smaller load moves to its extreme position. This means two manual pumps, which is not cheap/easy to get, and it's hard to find a place for them where they aren't visually distracting.

Front axle and steering:
The first axle is pendular: not a rigid axle as in real life, but an independent suspension with the two arms connected with a beam. The wheels stay more vertical and more away from other parts which is important as the things between the wheels are already as narrow as possible (the front loader arms, body panels and battery box are all there). Another advantage to a rigid axle is the stronger chassis and wheels support (the vertical space for reinforcing the chassis and supporting the axle from both sides is limited by the battery box).
The wheels still touch parts when fully steered but there's no jamming or noticeable resistance: the front wheels can touch the arm elevator cylinders and the rear wheels can touch 1-1 rollers placed there deliberately to prevent the wheel from jamming into beams there (the extra rollers wouldn't be needed if the hub parts didn't have so much backslash).

No lubrication was applied to the parts.

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You can find the brickshelf gallery here: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=566673

Video:

 

Edited by Lipko

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Jonfensu   

Wow wow! It's like a 8455 with steroids. It's really awesome! I mean, the shape is perfect, everything is well proportioned, the details :wub:....  One thing that I really like is how you include a working steering wheel because in most of the cases,  it's omitted in construction machines. 

Waiting for the video anxiously 

(Why you make this to me,  I mean, you make me  want to build a Telehandler,  and now I want to build a Backhoe :laugh:)

 

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I am fully aware of the issues and unlikely chance that a Technic model would ever get accepted for LEGO Ideas.... .BUT, if there ever was a submission that had a chance..... I think it would be something like this.  Love the build... also waiting to see the video.

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It is very nice MOC but 1 or 2 months more have given a perfect backhoe because this one seems to me a bit unfinished. Bigger buckets or small tractor?, I don´t know what I would have done.

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Lipko   

Thanks for the replies!

Yes, there's a lot to be desired about the model, I didn't have enough time to polish the model. And yes, the both buckets are off scale. I had the idea of a pneumatic backhoe earlier than the contest, but I gave it up due to the scale issue. I picked it up only because the contest. Anyway, I'm getting to like machinery, maybe my next model will be better.

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Absolutely fantastic! It's one the best backhoes I've seen. 

My only criticism, like others have said, is the back hoe could be beefed-up a bit. Other than that, I love it. I could only dream about making such a model, but it's inspired me to try! 

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proran   

Wow! This is incredible! The thin cylinders really shine here. I love these loops you've used to route the tubing out of the cylinders at the front bucket. I was looking for an elegant solution for that for a long time and yours is perfect. Legal and compact. And the color-scheme! It shouldn't work, but it does. It is also nice to see a backhoe with the front and rear wheels of the same size for a change. Could you expand on that not-independent double wishbone suspension in the front? I understand that it behaves like a rigid axle, but I would really like to see the details of the implementation. Thanks and congrats on a great model!

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