allanp Posted October 19, 2015 Posted October 19, 2015 (edited) If you are already planning for it to be a long build, I suggest you build a full size, fully featured prototype that looks like utter crap. Have you ever seen the first prototypes for some official Technic sets? They look horrendous, but the point of them is to find out all the problems you are going to run into and then to solve them. After you have done that you can build a second version where it starts to take on the shape of a finished model, then you build a third version and as many versions as it takes to get your finished model. The point is, for now don't concern yourself with what it looks like or having all the parts being the same colour. Just be sure to finish it so that it is complete and working before you move on the next version, and repeat as needed. Edited October 19, 2015 by allanp Quote
aminnich Posted October 19, 2015 Author Posted October 19, 2015 I was actually going to do a lot of pre building in LLD, but you never get to test the functions in LDD. So building mutliple prototypes is probably the rest way to go. Thanks for the suggestion Quote
allanp Posted October 19, 2015 Posted October 19, 2015 (edited) LDD is a great tool, but not for this project. It's size, weight and structural stability are going to be some of the problems you will have to deal with. LDD will not help you there. Take for example the slewing of the boom or the drive to the wheels. These functions due to the size and weight are going to put huge strain on gears and axles. Slewing (rotating) the crane might require a custom built turntable with rollers and multiple drives. But you don't know yet. This is why you need to build a functional proof of concept that doesn't have to look anything like the finished model, but it will have all the functions and will give you an idea of how best to go forward. Here's an artical on how they designed 8043 over at TechnicBRICKS. http://www.technicbr...43-part_19.html Edited October 19, 2015 by allanp Quote
aminnich Posted October 19, 2015 Author Posted October 19, 2015 Thx allanp, This is indeed a huge project and your right LLD will not be much help. Making prototypes is the way to go Quote
aminnich Posted October 20, 2015 Author Posted October 20, 2015 I have been messing around on LDD for awhile ( im not home to actually build) to figure out a driven steering axle with 13L gear racks. I want their to be differentials and i dont want to change the steering angle by changing the length of the arm. So im wondering if anyone has come across with kind of axle. I also dont want suspension, just so you know. My only thought is to make all the steering arm longer and the same length and gear up or down the steering. this way making the arms longer i can fit a differential into the axle, otherwise it isnt wide enough Quote
allanp Posted October 20, 2015 Posted October 20, 2015 (edited) Only 2 days since your first post and you are asking for designs for your axles? This is not good. Not trying to be rude, I would really like to see you succeed in designing and building this massive crane yourself. There is absolutely no way you have reached your current design potential after only two days of work in LDD. Give yourself more time to be the great designer that you can be, you got this man, so JUST DO IT! Edited October 20, 2015 by allanp Quote
aminnich Posted October 20, 2015 Author Posted October 20, 2015 Your totally right, i guess im too lazy haha. No more asking for help on my end just posting WIP pictures. Quote
aminnich Posted October 21, 2015 Author Posted October 21, 2015 So you wanted to see some bricks, well i have some virtual bricks to show you. It is with LDD because it is easier to make internal changes in LDD than it is actually building. I started actually building, but changed over to LDD. Here are some screenshots of the design and with 12 of them lined up (but keep in mind that only 6 of the 12 axles will be driven) I have a bunch of ideas to change the steering modes, but im going to actually build that because i hate doing gears in LDD Quote
TheItalianBrick Posted October 21, 2015 Posted October 21, 2015 Ok, I would use normal hubs to keep things simpler and cleaner. Any of those pins you are using could snap out due to the weight of the crane. Then, you will need different gear reductions for the steering racks (not different rack arm lengths) so when you apply the crab mode they will all go on the same directions at the same angle. With 12 axle to steer will end with a massive "gearbox" just for steering.....so if you can avoind crab steering. Quote
MaxSupercars Posted October 21, 2015 Posted October 21, 2015 (edited) Aminnich... just notice... count with that with U-joint you are limited to 45 degrees by driven steered axles... So use driven axles just in the middle if you then use bigger angles at the ends... Max... Edited October 21, 2015 by MaxSupercars Quote
aminnich Posted October 21, 2015 Author Posted October 21, 2015 Ok, I would use normal hubs to keep things simpler and cleaner. Any of those pins you are using could snap out due to the weight of the crane. Then, you will need different gear reductions for the steering racks (not different rack arm lengths) so when you apply the crab mode they will all go on the same directions at the same angle. With 12 axle to steer will end with a massive "gearbox" just for steering.....so if you can avoid crab steering. The problem with your suggestion, is that i dont have hubs you are talking about. I wish I did because that would have been very helpful. As for the change in steering modes, all of the steering arm lengths are the same and i was planning on doing a lot of gearing up and down to get different gear ratios. The 'gearbox' is going to be just a long axle going down the middle that will move back and forth to change the gear ratio from 1:1 (crab) or whatever the other ratios are. Like I said, i want to test out different ideas. Aminnich... just notice... count with that with U-joint you are limited to 45 degrees by driven steered axles... So use driven axles just in the middle if you then use bigger angles at the ends... Max... Thanks Max, The plan was to use the axle idea above for the middle 6 axles, 2 of which when in regular steering mode wont be steering at all, The other axles, 3 front and 3 back, will not be powered and will have a larger tuning radius. Thanks for the reminder tho :) Quote
TheItalianBrick Posted October 21, 2015 Posted October 21, 2015 The problem with your suggestion, is that i dont have hubs you are talking about. I wish I did because that would have been very helpful. As for the change in steering modes, all of the steering arm lengths are the same and i was planning on doing a lot of gearing up and down to get different gear ratios. The 'gearbox' is going to be just a long axle going down the middle that will move back and forth to change the gear ratio from 1:1 (crab) or whatever the other ratios are. Like I said, i want to test out different ideas. Well can I be honest with you? a 12 axle crane it's something that could end up being a 5000-10.000 pieces...depends on how well is designed. Sounds like you don't have all these parts or not willing to buy some.....if this is the case then the result will be the same as may other fail attempts: poorly designed cranes, unstable, understuctured and with a color scheme similar to a parrot! Anyway, regarding the steering...don't underevaluate the problem....creating a switchable steering system it's a very very very complicated thing.....on a 12 axle crane even more complicated! Quote
Alasdair Ryan Posted October 21, 2015 Posted October 21, 2015 Before you rush into making such a big crane,you should first try to make a small crane (3-4 axle) if it works then you can scale it up. Doing this will highlight any problems that may arise in building a bigger crane. Quote
aminnich Posted October 21, 2015 Author Posted October 21, 2015 Well can I be honest with you? a 12 axle crane it's something that could end up being a 5000-10.000 pieces...depends on how well is designed. Sounds like you don't have all these parts or not willing to buy some.....if this is the case then the result will be the same as may other fail attempts: poorly designed cranes, unstable, understuctured and with a color scheme similar to a parrot! Anyway, regarding the steering...don't underevaluate the problem....creating a switchable steering system it's a very very very complicated thing.....on a 12 axle crane even more complicated! Bricklink is going to be my new best friend for this build, if hubs are necessary, when i will buy some, but id rather try out building something with what i have first. Before you rush into making such a big crane,you should first try to make a small crane (3-4 axle) if it works then you can scale it up. Doing this will highlight any problems that may arise in building a bigger crane. Im going to do this with my steering ideas. Im going to build a 4 axle (basically the middle of the 12 axle crane) and try to get the steering right. From there, i can add steering axles on both ends of the 4 axle setup until 12 of them for present. Quote
MaxSupercars Posted October 21, 2015 Posted October 21, 2015 (edited) Aminnich... don't let to talk it out... If your project just ends with 12 axle chassis because of other problems it will be not so bad because you test new things... If everything will be heavy you can cancel it or rebuild any time... And to ordering new parts or missing parts... no one says that you must finish this project in 2 months... you can work on it also half a year or whole year... I got my 9 axle mobile crane 5 months in WIP status because of lack of time and other projects like my Tatra 8x8 (which I rebuilded maybe 10x) etc... For me is sometimes not important final vehicle but WIP vehicles and semi-solutions where I test my ideas and got a lot of fun by building... Max... Edited October 21, 2015 by MaxSupercars Quote
aminnich Posted October 23, 2015 Author Posted October 23, 2015 (edited) I just wanted to warn everyone not to use the axle above, it sucks I had time to build it and it doesnt hole up to weight at all, the pins pop out of the 5x7 beam. I want to give a shout out to TheItalianBrick for your help! It was recommended to use hubs for strength, and im thinking that is the best possibility. EDIT: how many driven axles do you think something like this would need. I was originally thinking the 6 middle axles Edited October 23, 2015 by aminnich Quote
Saberwing40k Posted October 23, 2015 Posted October 23, 2015 I'd say that you're about right. Most cranes, even the big ones, only have 8 wheels driven. I don't know anything about the Zoomlion Qay 2000, but the Terex AC-1000 has 4 axles driven. However, they are not the center axles, for reasons not quite clear to me. This model shows where the driven axles are. I presume that they work that way so that no driveshafts have to pass through the the area directly under the turntable, because that area is so critical. Also, all cranes with star outriggers have the base of the outriggers connected directly to the turntable support. That way, the crane chassis does not have to support the weight of the boom, counterweights, and load when the crane is in use. And, it means that any load is translated more directly to the ground. Quote
aminnich Posted October 23, 2015 Author Posted October 23, 2015 Good to know, thanks. I'm wondering how many axles you think it will take to move this beast? Quote
bonox Posted October 23, 2015 Posted October 23, 2015 I presume that they work that way so that no driveshafts have to pass through the the area directly under the turntable, because that area is so critical. this quote may be of interest http://www.eurobricks.com/forum/index.php?showtopic=99748&st=550#entry2363641 A cross type outrigger set may well negate the design rules that force certain configurations with stabilisers running across the frame. Quote
MaxSupercars Posted October 23, 2015 Posted October 23, 2015 (edited) I'm wondering how many axles you think it will take to move this beast? The number is not so important as the good grip (contact with the ground)... You can move it also with 2 axles... for ex. in my crane when I put the main weight of superstructure on non driven axles, I got problems with grip because driven axles were not so loaded... from this reason is very good solution to use suspension at least on driven axles to maintain good contact with the ground... as I said... you can move the crane also with 2 axles but with that under the turntable... Max... Edited October 23, 2015 by MaxSupercars Quote
aminnich Posted October 24, 2015 Author Posted October 24, 2015 So you guys wanted to see some bricks, well i took my Friday night to build a prototype chassis. I didn't build the change in steering gearbox and the drive motors are not hooked up, but the idea is there. I need to add a space in between the first and second half sets of wheels for future regular steering. 12 axles, 24 wheels, 2 servos Quote
JJ2 Posted October 24, 2015 Posted October 24, 2015 (edited) Looks at picture *Rubs Eyes* Looks at again..... Assumes that he is hallucinating. 1 Min later... HOLY MEGABLOKCKS! That this is huge! Looking good so far One thing though, wont only 2 servos limit the steering angle to only 2 different angles? Or am I wrong? It seems like if that is true it might put huge forces on the chassis. I need to read more :) Edited October 24, 2015 by JJ2 Quote
aminnich Posted October 24, 2015 Author Posted October 24, 2015 Hahaha, thanks JJ. How you can see why I call it the massive crane Quote
750ACE Posted October 24, 2015 Posted October 24, 2015 Dave21 posted what looks to be the same axles in the axle thread a few hours ahead of your post. Was his post inspirational? Quote
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