cemus

Steering for Trailer Wheels?

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guys, hello.

I'm an AFOL, I own sets since 1992, had a break for a couple of years and then since 2010 my lego technic enthusiasm just grows bigger and bigger..

my biggest passion is heavy haulage, with all due respect to Jaap, 2legoornot2lego and other honorable members that created the great heavy haulage models over the years. I've been trying to build a truck and a trailer; with 60 studs in length, 19 studs width and 23 studs height for the truck and, 120 studs length, 19 studs in width and 11-13 studs in height for the trailer..

basically, I'm trying to build something like 8258, with a trailer that can safely carry my 8043/Volvo 42030 Loader..

this has been a two year project for me, but you know how time consuming is the work, wife and kids... also, I had some serious problems with the trailer stability, like bending issues with the load.. now I'm over them..

now I have two problems.. I have no knowledge of suspensions, pendulum would be nice for me but I don't think I have the parts required to build such a thing..

also, the reason this topic exists, steering of the wheels on the trailer.. you know some trailers have turning wheels for the sake of turning radius, and I know someone somehow implemented it to LEGO Technic via the position of turntable on the fifth wheel, god knows how. so any ideas would be appreciated.

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I know someone somehow implemented it to LEGO Technic via the position of turntable on the fifth wheel, god knows how. so any ideas would be appreciated.

You could buy Jaap's instructions and find out. It's an electrical solution, not a purely mechanical one, and requires the rechargable battery box, but it's simple, ingenious, expandable and robust. Perhaps he'd be willing to share the idea without a purchase, but i'm unwilling to steal his thunder and I very much like his trailer.

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One of Designer Han's trailers is steerable and I think the instructions are free.

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thanks for the replies.

this is as far as I could get.

KRi1RLc.png

the front axle had angled steering but somehow I messed it with the LDD so I couldnt show it to you..

the problem is that, I'm planning to control the truck remotely, so two things:

1- how do I make the trailer wheels turn, when I turn the truck's wheels?

2- how do I apply an ackerman geometry steering, by using that 13 studs steering arm :D? I think I'll go on with the Sariel's 13 studded ackerman steering model for that one.. servo motor doesn't work really well with it, but I'll find a way.

ToZHWaK.png

this is as far as things gone.. it'll be a lowboy trailer if I can sort things out.. that 2 red 3x5 L shaped liftarms show where the trailer starts and ends, it'll be something like 120 studs long. I already have 8258 but I think I wont be bothered to modify it for remote controlling that thing, I'll either use the AROCS I have, or I'll build a whole new truck for it.

and while we're on it, pendulum suspension for 3 axles.. what am I gonna need for it?

Edited by cemus

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Welcome to Eurobricks Clemus,you could connect the wheels of the trailer to the same port as the steering of the truck.

In order to control the wheels of the trailer you could use a servo connected to a switch to control the direction (and to turn off steering completely).

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Welcome to Eurobricks Clemus,you could connect the wheels of the trailer to the same port as the steering of the truck.

In order to control the wheels of the trailer you could use a servo connected to a switch to control the direction (and to turn off steering completely).

dear alasdair;

thanks for the welcome.

I'm planning to use only one IR receiver so, a solution that steers itself depending on the position of the fifth wheel will be a killer for me.

if not possible, then I'll be using the second IR receiver with the servo. but this will upset my Volvo A25F truck :)) or I'll buy an IR receiver with the addition of an XL motor because I feel that in a truck that big, one XL just wont do the job.

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dear alasdair;

thanks for the welcome.

I'm planning to use only one IR receiver so, a solution that steers itself depending on the position of the fifth wheel will be a killer for me.

if not possible, then I'll be using the second IR receiver with the servo. but this will upset my Volvo A25F truck :)) or I'll buy an IR receiver with the addition of an XL motor because I feel that in a truck that big, one XL just wont do the job.

You could hook up both servos on the same circuit and get them to steer opposite by hook everything up to one channel on the reciever, like this:

Battery box---Receiver

/ \

drive motor servo for truck---pole reverser (have to experiment to see which side to keep it on)---servo for trailer

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About steering axles on trailers:

You really need an system which is based on the rotation of the fifth wheel compared to the trailer.

If you hook the steering of the trailer on the same port as the steering for the truck you will end up with a combination which will be impossible to reverse in a proper way.

The 8 axle Nooteboom which i have designed uses fully automated electronic steering with 100% LEGO bricks. It's a piece of cake to reverse the Nooteboom into tight parking spots for example.

I will show a video of the trailer in action. As you can see it works totally smooth behind the truck.

For those who are interested in building such a system i can only say, have a look at my instructions which are available on my website.

1 tip for your trailer which i base on the pictures is see here. The differences between the angles of the steered axles are way to big for a trailer this long.

Your turning point will be around the middle of the trailer so when you put an non steering axle on the middle of the trailer you can clearly think about the steering angles on the rear axles.

Hopefully that will help you out with the angles.

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About steering axles on trailers:

You really need an system which is based on the rotation of the fifth wheel compared to the trailer.

If you hook the steering of the trailer on the same port as the steering for the truck you will end up with a combination which will be impossible to reverse in a proper way.

The 8 axle Nooteboom which i have designed uses fully automated electronic steering with 100% LEGO bricks. It's a piece of cake to reverse the Nooteboom into tight parking spots for example.

I will show a video of the trailer in action. As you can see it works totally smooth behind the truck.

For those who are interested in building such a system i can only say, have a look at my instructions which are available on my website.

1 tip for your trailer which i base on the pictures is see here. The differences between the angles of the steered axles are way to big for a trailer this long.

Your turning point will be around the middle of the trailer so when you put an non steering axle on the middle of the trailer you can clearly think about the steering angles on the rear axles.

Hopefully that will help you out with the angles.

dear jaaptechnic;

I'm really flattered by your response. the idea of building a trailer is inspired by your and designer-han's excellent trailer sets. especially yours look effing brilliant!

it'll be a only 3 axle trailer, so I got the exact steering idea from the 42009 mobile crane mk II set.. I don't know how it works yet so, I'll adjust the steering angles accordingly..

I'm thinking maybe a system with the outer teeth of the 60-tooth turntable would work wonders for the rear steering.. when it turns with the correct level of gearing, rear wheels would turn.

thanks for the ideas, really appreciated!

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I'm currently working on a 3 axle trailer in 42024 scale and I have chosen for a mechanical solution based on linkages. Using gears poses a danger of the mechanism skipping a tooth and getting out of alignment under strain. I don't have any pictures at the moment, so I will try to describe my setup:

I used an extra pin in the 5th wheel to "detect" the angle between the truck and the trailer and send this via some linkaged to the trailer axles. At this scale I haven't bothered with ackerman geometry, but the steering of the second and third axle is proportional with the aid of different link lengths, the first trailer axle is not steered.

I have found that my prototype is very reliable and smooth, but I have ran into an issue with this: When the trailer is loaded, the inevitable bending causes the link getting caught and as a result the steering become jerky.

Good luck.

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i used a turntable and a gear to steer the trailer. it didnt work though. There was too much backlash and the trailer did'n steer properly. Maybe a linkage would work. see cumulonimbus' post

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I dont think a linkage would work for trailer steering... actually my mind cannot comprehend a way to work that out..

I think I'm going to cancel steering on trailer.. but help on pendulum suspension would really be appreciated..

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I made a 3 axl lowloader for my Arocs slt. Made the steering in a flashlight just like the Arocs.

This is a simple way.

Didn't want to use any motors and the neck is detacheble so links wound't work eighter.

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I tried making a steerable drawbar trailer years ago using a simple linkage setup.

http://vid98.photobu...AxleTrailer.mp4

I think I ended up making the middle 2 wheels nonsteerable.

this is excellent. now only if I can find a way to implement this to a lowboy..

I made a 3 axl lowloader for my Arocs slt. Made the steering in a flashlight just like the Arocs.

This is a simple way.

Didn't want to use any motors and the neck is detacheble so links wound't work eighter.

actually I'm now building the AROCS from scratch to understand the flashlight steering mechanism and robustness, but I dont think I can work it out that way.

the trailer consists of 3 parts; deck, back with wheels and gooseneck. I can say it's now %15 done. the deck is almost done.

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ok now; after weeks flied past, I've been able to install and sort my huge table, got LEGO's sorted, installed PC and speakers... now time to build as long as my baby allows me to :D

I've been going through ingmar's (2legoornot2lego) and designer han's trailers and I've come up with this info

So how does the rear steering works? A technic turntable (with inner axle) is used as kingpin to couple on the truck's 5th wheel. The turntable is locked on the truck in such a way that it's gear 'measures' the position of the truck irw the trailer. The turntable's gear position is passed via chains to a 2nd technic turntable in the inner middle of the trailer. That turntable passes (with a fixed inner axle) the position to an PF Rechargable Battery Box's motor speed control. The motor speed control dial can turn 90 degrees in both directions in 7 steps and therefore precisely being able to control the PF Servo Motor in the same way. The PF Servo Motor drives a traditional double 1x4 gear rack, passing it's output to a technic turntable whereof the rear twin wheels are mounted.

Remark: I tried a 3rd steered rear twin wheel but the PF Servo Motor was not powerfull to operate a double steered twin-wheel setup.

further reading on http://designer-han.nl/lego/index.htm ...

extremely hard for me to understand.. also, I don't have the required electronics. I have a couple of ideas lined up so we'll see what I can come up with.

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I have done this in the past just by linking the steered trailer wheels to the angle between the bogie and the trailer body. In the crudest case, a pin down from the trailer body attached to a leading steering arm will turn the bogie in the direction the trailer is turning, but with the lag you want. I used something a little more controllable but that is the basic idea.

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