Tri-axle half pipe tipper trailer

[ricm]

OK, so it's more than twin axle but it is for on-road use so have put this thread here instead of under the 'Construction Equipment' section.

The fabricated Aluminium body for my next project arrived from in Canada earlier this week, built to my specs by RCP57 who mostly builds tipper bodies to fit the standard King Hauler chassis:







1st class quality fabrication, really happy with it.

FYI, the pics above were taken before RCP57 put it in the mail to me - so don't ask me about the things in the background!

This is going to be a bit of a slow build, but will update as I make progress.

Chassis will be based on the Tamiya container trailer, with the whole axle group moved forwards by 1 axle spacing. Plan is to build in motorised support legs and everything fully wireless, with a screw drive mechanism for tipping using a 540 motor and 100:1 gear reduction which -should- be able to shift almost anything. I need this thing to cope with a full load of sand, otherwise what's the point....! All electronics have already puchased and/ or designed, built and tested.....

Got the chassis rails back from the machine shop. As usual, first class job. Both sides drilled with a few extra holes for the new axle locations

one side built here, showing custom chassis cross members to allow all the extra bits to be fitted. Black box at the back is the receiver board for the wireless control

decided to ditch the lower swing arms on the original suspension, they do nothing more than restrict axle movement





Adding the motor, gearbox and tipping drive screw



Other side rail....core chassis complete





So it'll look something like this but still loads to go.....

[Claus]

Sooooo NICE!!!!

[heavy_duty]

Great vision and great execution. That trailer looks prepared for any load you can throw at it. AWESOME.

Ed

[Espeefan]

That's awesome. I always thought Reg should start building tubs for the end dump trailers too. Looks like he made one!

So I have to ask, where did you get the Hayes truck in the background? Just kidding!

[Stuff]

I wanted to do a tipper on the container chassis... just cant find a cheap container chassis lol

you got this one in the bag for sure!

[ricm]

Originally Posted by Stuff

I wanted to do a tipper on the container chassis... just cant find a cheap container chassis lol

you got this one in the bag for sure!

I bought a brand new container trailer then separately sold off the unbuilt container, the decal sheet (since 95% of the decals are for the container anyway), and all the twistlocks with their brackets. Recovered enough cash to make the effective chassis price with axles etc around $100 which I think is decent value compared to scratch building the equivalent....

[avel]

Very nice looking dumper!

[4X44DAD]

this is awesome who makes the screw drive mechanism and 100:1 gear reduction motor?

[ricm]

Originally Posted by 4X44DAD

this is awesome who makes the screw drive mechanism and 100:1 gear reduction motor?

check out these guys for gear motors - massive range covering almost any parameter (voltage, RPM, reduction ratios, physical size). this was the best selection I could find anywhere. They also stock a good range of bearings, brackets, hardware and electrical items for the DIY model enthusiast....

http://www.technobotsonline.com/inde...ategory_id=176

I basically went for the biggest motor I could fit between the chassis rails with 7.2V supply, then picked a gear ratio to provide reasonable tipping speed which should be about 30 seconds each way.

machined stainless steel screw drive came from these guys in the UK who will cut and sell to almost any length if you email them, I wanted only 250mm with matching nut and they charged the proportion based on the 'per metre' price:

http://www.worldofcnc.com/collections/trapezoidal

a but more expensive than buying standard threaded bar from your local DIY store, but the screw is 100% STRAIGHT (!) and since it is CNC machined it will have much less friction - especially under stress - than cheaper alternatives.

[Lmackattack]

I like that screw drive. looks well made. wish I had seen this before I used a ace hardware threaded rod in my end dump.

I also used tecnobotsonline for a reduction unit on my 1/4 frame. I went with a 50:1 and it lifts a full box of wet sand in about 20 seconds. power comes from a 7 cell battery. You can hear the motor is working to get the box moving but once its a few degrees off the tractor its smooth sailing. your 100:1 should be just fine for the task.


Keep the pics coming!

[1985 kenworth]

nice trailer so far keep those pics coming

[RCP57]

Hey Ric, it's great to finally see what I was building the tub for! I hope everything I did works out as planned. It looks like a great setup you have created and I can't wait to see the finished product.

Thanks again for allowing me to be part of it!

Reg

[ricm]

Originally Posted by RCP57

Hey Ric, it's great to finally see what I was building the tub for! I hope everything I did works out as planned. It looks like a great setup you have created and I can't wait to see the finished product.

Thanks again for allowing me to be part of it!

Reg

no worries Reg - I've shown the tub to a few folk here in Aus and they've been quite impressed....I'll see if I can convert a few for you

[ricm]

So I said this would be a slow build, but I got some more done over last few weeks...

rear end with hinge and bumper brackets



rear under-run bar



light lenses missing but otherwise mostly done






Underside view of the sub-frame for the main body, got the control for the tailgate hooks underway. The push/ pull rod will be activated by a part of the tipping mechanism

[bigford]

looking real good post up a vid soon!!

[JAMMER]

Great job on the trailer and the dump angle looks good it will dump anything with out a lot of problems. Ed

[Exclusive RC]

Reg does some beautiful work for sure... This looks like it's going to be a pretty sweet trailer when done..., keep those pics coming, good work

[ricm]

moving house over Christmas break - I'll put up some more pics in January.

got to make the telescoping hoist ram, sort the limit switches for the mechanism, then powder coat the bin....then should be done...

[ricm]

I figured time for an update....only 10 months since last one....but 2x house moves later.....



got all the parts made so stripped the trailer right down to get all the Aluminium bits anodized. Now in the process of final build:











Close up of right hand side 'tool box', contains the battery pack for the motorized legs









Some technical challenges...



1) tipper drive control

I originally designed a relay H-bridge for the tipper control (shown earlier in this thread as a small circuit with 2x blue relays side by side), the advantage being that the motor receives maximum power from the battery. This tested fine in manual 'over-ride' mode, and the relays also worked fine with the wireless control when not hooked up to the motor. I found that with everything connected up for final test, the relays would click on and off at high frequency when using the wireless control....but all still OK in manual over-ride mode. After some head scratching, I realized that the motor is drawing too much current at the instant of being turned on because it is, for a short time, effectively a short circuit (the stationary motor has no electrical resistance...only when the motor starts to turn, thereby creating a back EMF, does it have some electrical resistance). The voltage was drops right down below what is needed for the wireless control board to work (the wireless controller and the motor share the same battery pack), therefore the whole thing was shutting down, relay turns off, voltage goes back to 7.2V, then the relay comes back on and the cycle starts again. Testing with separate batteries for motor and wireless controller, which worked fine, proved the point....



So, I've had to revert to finding a basic speed controller with limit switch inputs for both directions (my motor and screw drive is powerful enough to do some damage if it over-runs the mechanical limits of the tipping mechanism!)



http://www.robotpower.com/products/wasp_info.html



The speed controller prevents the initial current surge to the motor, thereby making sure that the wireless controller will always have enough power from the same shared battery.



It also means that I've had to completely rebuild the manual over-ride control, which now consists of a servo tester which can provide a signal to the ESC instead of the wireless controller. You can see this at the bottom of the pic of the underside of the trailer. This will all get built into the left side 'tool box'.



Learning point....for big fat motors, use a dedicated power supply if using a direct 'switched' control (like a relay) to protect anything else from current surges. Otherwise ESC is the way to go.





2) axle heights

this chassis was based on the container trailer, with the whole axle set moved forwards by 1 axle spacing. If you have a container trailer, you may have noticed that the front axle is often just off the ground because I don't think Tamiya quite got the axle heights right. Effectively, the trailer isn't quite horizontal when hooked up to a prime mover and the suspension doesn't allow for the difference to be absorbed. This design problem becomes more obvious with a shorter trailer (like I now have), since the chassis sits at more of an angle. So I added some spacers between the axles and the springs to allow the trailer to sit at the right angle whilst also allowing full movement in the suspension. Without the spacers, the suspension system does take up -some- of the inequality but it is then limited as to how much more movement exists for a bumpy road surface. So no spacers on the rear axle, 3mm spacer on the middle axle and 6mm spacer on the front axle. This is why there is more clearance between the wheel and the arch at the front axle compared to the rear axle. It also meant that the king pin was a the right height for the auto-support legs to work, which are sensitive to too much variation with the height of the coupler on the prime mover....



Next update....hope to have chassis fully built, all wiring installed and tested. Yet to get the bin powder coated (white)

[ricm]

should have uploaded these a while ago....build ended up being a bit more $$ than I budgeted for but really happy with the result :-) I did a dump test with over 10kg load at the very front end of the tipper body. Worked so easily I wondered if I had well over-engineered the whole thing. But rather that way than the alternative!