[TC8] [WIP] GSK55 Grove Trailer Crane

[Kristof]

I honestly don't believe these outtrigers will be very functional. I mean with the crane this big, you need some real support, not only good looking fancy contraption. This will be way to bendy to effectively support that weight. Shorter but sturdier outtrigers would do much better in my oppinion.

If you decide to try this concept anyway, I suggest you to roatate the blue and yellow part 90° (along the axix of extension, so you have the axle holes facikng up and down) in order to reduce the up-down play in the mechanism.

[Erik Leppen]

Miguev, you are right, it would give smaller turning radious, BUT, since this is a trailer, not a truck (or mobile crane), it has to be like this, as he does not want to have center of the rotation in the middle (or worse, at the back) of the trailer.

You don't want it at the front either.

But I think multi-axle trailers are hard anyway, because the steering depends on the angle between trailer and truck. In reality this is probably done electronically, and, I think, this has a reason, because it's not as simple as with a fixed-body truck.

[aminnich]

The steering is good. I tried pulling it around with the truck I quickly made for this trailer and it seems to work well.

@krisandkris12; thanks for your advise regarding the outriggers. Everything u said makes sense. My thought was go wide with the outriggers for more support, but ur right they are not sturdy and won't hold up. A not as wide and stronger setup would be better. I'll try making something today to post

Like I said, im trying to make it fairly compact so it fits where i want it, but i dont have pneumatics to use as the up/down part of the outrigger

Edited September 26, 2015 by aminnich

[Kristof]

^ Width is not what you need. The height is what matters. Classic beam is the excellent example of this - the vertical part is what prevents beam from bending and yet it can be fairly thin. Those flat ends prevents twist and side to side bending but don't add to much to horizontal strength.

If you use about 3 or 4 long liftarms stacked on top of each other (holes facing up), you can easily attach 1x4 gear racks on one side (bottom) and guides for axle that provides up/down function on the other. That way you can bypass pneumatics and use small LA.

[aminnich]

Like I said, i want to experiment with the outriggers. I was hoping for a wider stance but, i think it will be better to focus on a stronger stance. I hope to get pictured posted by tonight

[miguev]

You don't want it at the front either.

But I think multi-axle trailers are hard anyway, because the steering depends on the angle between trailer and truck. In reality this is probably done electronically, and, I think, this has a reason, because it's not as simple as with a fixed-body truck.

Thanks (Milan & Erik) for clarifying, I was confused.

[theozboy]

Most trailer steering is accomplished by either steel cables or steel rods that are attached to a turntable on the 5th wheel. A small wedge shaped piece sits just to the rear of the king pin which engages in the slot on the 5th wheel. As the trailer twists on top of the 5th wheel the wedge is turned, pulling on one rope or the other which is connected to the wheels. Normally wholly mechanical.

Or the wheels are just floating and the castor of them makes sure that they follow the vehicle track. If this system is used then there is quite often a lock out to lock the wheels straight ahead for reversing.

For heavy loads such as your crane then I would expect it to be of the positively steered type. My experience is from a couple of years ago when I was an hgv mechanic, there may well be electronic versions now but I doubt it, as the trailer wouldn't be able to be used on any truck, as most trucks wouldn't have the electronics as standard to supply the data to the trailer. Also the trailer would need some sort of power on board to power any hydraulic system to steer the rear wheels. Hopefully I've explained this well enough for you to understand!

[aminnich]

Here is an updated outrigger idea... One section but a lot stronger than the double. Of course it is half the length

[aminnich]

Alright, so I made a mock up of the Outrigger design that i last posted. As you can see by the pictures it is about 6L too wide so i have to change that, but other than that, it seems to be fairly strong. The only thing i dont like about it, is that it uses a lot of parts that will be needed for the rest of the build, so that could be a problem..

[Milan]

If you feel you are using too much time and parts on the outriggers, make them dead simple, but effective. Use just the beams that can slide in and out of the outrigger box. When you want to deploy them, just attach manually some piece(s) that would represent lifting cylinder. That way,you can concentrate on the crane, and then later if you have more time, you can upgrade them.

[Kristof]

I agree with Milan and will only repeat myself - Narow, rather tall beam. This looks to bulky, both the outtriger and the 'feet' mechanism housing.

[Erik Leppen]

Same here. I think you should startg thinking about the actual crane part - the turntable and boom. Those will be the biggest challenges. If you have those, you have some idea of the size of it all, and what outriggers could fit with them.

But, that's the thing if you build a six-axle trailer. The "small models small problems, big models big problems" adage is probably even truer for cranes ;) (And, to be honest, I don't really understand why you don't just build the model from the original image with the three-axle trailer.)

[aminnich]

And, to be honest, I don't really understand why you don't just build the model from the original image with the three-axle trailer.

The very first original plan before i started building was to make this model exact, but since the crane is a concept and their are not a lot of actual cranes, just a few drawings and a few actual cranes for expos and what not. I dont really have specs to follow to match the crane. So the only part that would mirror the crane would be the 3 axles. So i figured, just base my crane off of the GSK55 trailer crane a little bit.

I made a list of the functions i am my build to be, but im sure 50% of them are not on the GSK55, so then again i would not be making the exact crane. Good thought, but their is not enough information about it to build it

[aminnich]

I think i am going to do a complete redo on this project. I think i am leaning more towards trying the recreate the actual crane, with a few upgrades. Ill probably make it a 4 axle crane though.

[Milan]

You have enough time, keep up!

[aminnich]

You have enough time, keep up!

time is only only concern. but i think i could manage it

[Kristof]

Good luck. I think this might be the right choice ;)

[aminnich]

I still do not have a lot of pictures to base the trailer crane off of. but i did a bunch of research on the crane and cranes that the company is basing it off of, so i have a little bit more to work off of.

[MaxSupercars]

Aminnich... you got my support... The crane must not be perfect and accurate copy of existing one... Lego is about compromises... The most important is that you have fun by building... :)

I like your multiaxle trailer... :)

Max...

[aminnich]

Thanks, but now i have a question for all of you, just to get a general idea of how far off of the actual crane you think i should go. I mean have have ideas from all kinds of cranes and i wanted to put them of this one.

I did a bunch more research of this crane and im going to do some more cool stuff and still making it more like the original GSK55. Im working on a boom good strong boom design in LDD right now, hoping for 4 good solid sections, but im afraid the first main section will get too large in diameter. we will see.

Thanks for all of your support guys!!!

[aminnich]

Ok, so i have been messing around with LDD for awhile. here are 4 sections of the boom, they are not at full length the boom will be 55L. On top of the second section will be gear racks for extension, the other sections will extend via fishing line. Here is a picture that shows a design of the beams, if you have any questions, i am all ears. Thanks

[Milan]

As we all told, use the first picture as a reference and build that. Why?

1.Its unique, you will probably be the only guy having that kind of crane.

2. It does not have drive/steer axle

3. You got plenty of space in the trailer for the outriggers/motors/stuff

But make it with just three axle + truck.

Watch out for the 4 sections. Better to finish one with half that size, and if it works, then upgrade it. 4 section will be very wide and heavy, maybe too much for the wheels you are using (see kiwi's Ltf, he will made smaller one). Its no so much about too thick boom, but about weight.

Edit: wow, your 4 section boom looks just like your outrigger design :)

Edited September 30, 2015 by Milan

[Kiwi_Builder]

I can attest to what Milan says. I built a two stage extending boom and I quickly found that while the boom worked perfectly and looked good, it weighed far too much. This caused major problems because with the current limitations of the lengths of LA's, they were unable to raise the boom because of the sheer weight with the pivoting point in a terrible location relative to the LA. This large amount of weight meant that there was incredible stresses on all parts of the boom and the areas surrounding it. No matter where you mount the boom on the superstructure, the counterweight required would be very large, causing yet more strain on all parts of the crane. All of this weight hanging off to the side of the carrier means that the stabilizers required would have to be massive and strong just to give it a better chance of not falling over.

Here's my thread with my problems with the boom: http://www.eurobricks.com/forum/index.php?showtopic=114888

[aminnich]

With the research I did, I found that the trailer has different optional add ons to the trailer. One of which is that the last axle to a free float steering axle, I have to figure out what exactly that is but I'll probably incorporate that. As for the number of axles I'm still debating 3 or 4 because of the weight that will be on the trailer. But i will b building a 3 axle first and test that would with some cans as weight.

Thank you both for your boom suggestions regarding the weight, the boom pictures I shared on the first page was a 5 section boom and it was heavy and strong. It was crazy big. What I made on LDD is basically the same thing except the 5th section wouldn't be used. I'm going to cut out a section and make the outside section of the boom smaller.

Edit: wow, your 4 section boom looks just like your outrigger design :)

And I can't figure out if this is a good thing or bad

[Kiwi_Builder]

How long are each of the sections because if two sections on mine are too heavy to be able to be lifted with anything Lego and refuses to do anything other than fall over there's no way you're going to be able to have four successfully. But I hope you will be able to somehow pull it together.