need help with dump trailer

[Sped74]

guys i cant seem to get my dump trailer to dump with using my linear servo?
i have tried to make a couple different lift mechanisms. any help you experts have would be great thank you

[Claus]

http://www.ebay.com/itm/Lifting-Mech...3D371719345417

[TRUCKMAKER]

Check out the link below for a more economical way of doing it. Start at post #14. You can do the whole screw drive for the money you'll have in the lift mechanism above. That being said I have one of the units above and pulled it out of my dump due to lift angle versus weight I could lift for the size of box I have. They're great for shorter boxes but larger trailers and dump boxes not so much unless you use a high torque motor.

http://www.rctruckandconstruction.co...ht=screw+drive

I've not tried linear servos so I cant comment on how they would do but pictures of your set up might help us help you figure it out.

[dozerbuilder]

Make your own as truckmaker says. I’ve got $800 worth of firgelli's I bought brand new lying in various stages of breakage, stripped gears and a box of broken parts of 6 of them at $75 each and a dealer who totally ignored my complaint, wouldn’t even reply to my email, so we’ve rolled our own. Now we can make any we like in any size and length in our own back yard. It's easy to do and way cheaper than a $75.00 firgellie or other proprietary type. If you can make a model, you can make these. I just finished the prototype for the lift and angle rams on my dozer build. There are many ways to make them and these heavy duty ones work well for me so far. Tilt cylinder and blade lift rams are next. These have a 55mm long stroke. If they were for a Bruder D11, they don’t need to be heavy duty. For heavy steel dozers like my one that weighs 60 lb, they need to be strong and simple in design.


The parts cost for one is as follows, all online from alibaba China:
1 x 100/150rpm GN14 gear motor = $9.80.
1 x ACME shaft 8mm dia, pitch 2, lead 4 =$4.78 for 4x200mm long acme rods including acme nuts.
6 inch length aluminium rail = $0.50
1 x bearing = $0.80
1 x ali tube 25mm O.D dia = $0.50
1 x 12mm O.D ali tube for pistons = $0.10
1 x rose joint 8mm I.D - $2.90

Of course the cost is broken down, I got bulk supplies of everything so I can roll one up anytime I need one from now on.
Now that I’ve made a pair, I could make one in about an hour, with all the parts on hand and access to a lathe to turn the end plugs to the required diameter to take the piston. You can make these any diameter, any piston length and size to fit your needs and they resemble a hydraulic ram. These ones will pull/push 7 lbs each tested on a bag weighing scale at the angle you can see in the pics which is way harder than straight up and down. I’m making a second type now with a larger planetary motor, aiming for 15lb pull. If you were making a bigger machine, the easier it gets since you can use larger dia motors and have more room each end. They are not perfect yet, but I’m nearly there. When I am, I going to make some simple jigs.

Compare these with the commercial ones. These are immensely strong and supported right through on a 16mm ali rail held with 8mm dia steel pins in each end. You can see the split plastic case on the commercial one sitting above the my DYO’s. One rip and the case split open. These are very strong, and the 8mm ACME drive rod is unbreakable in this application. Don’t use a threaded rod, it’s not designed to pull or push – an ACME rod is specifically designed for this purpose and works great. That’s the key to these, the ACME shaft, and choose your pitch and lead to match your motor speed to get the desired piston speed. These are running 8mm stroke per second. The ones I have for the blade run at 16mm per second. About right for 1/16th scale. You can see how that bearing is pounded onto the acme shaft as an interference fit and I have added Loctite. It holds it in place and puts no lateral tension on the motor shaft. It was a bit difficult to make the D in the shaft. I need to perfect that next. The motor shaft needs to “float” in the shaft D. The weakness will show itself soon and if it has one it’ll be the gear motor. I’ll simply make it stronger but they seem to work fine. Soon I will test it down at the closed coal mine ripping and we shall see how they go with 39lb of drawbar pull on them. Then we will know what to improve. Meanwhile, we can roll them up in no time to any size at all.

[TRUCKMAKER]

Nice job dozerbuilder they look good, been thinking about something like this, just don't have a lathe readily available.

[dozerbuilder]

Nearly there truckmaker, I think the larger planetary motors will just seal the deal when they arrive from China. These can be made any length, like a few mm stroke or 10 inches, just lengthen or shorten the rail, acme shaft and tubes accordingly. No limit. Yes a lathe is needed to turn off the aluminium end cap to fit inside the outer barrel tube, drill it in the chuck dead straight and turn off a nice end on it to look authentic like a hyd ram. That only took 10 mins on the lathe so a shop would not cost much. Going to make two more in the morning to complete the 4 x barrel ripper set. When I have them nailed I'll put up a set of pdf plans and material list here so those that want to go all-electric can use them and mod to suit.

[Rvjimd]

Dozerbuilder,

Thanks for the actuator info! Can't wait to see the plans! Not sure I understand the attachment from the D shaft of the motor to the screw? Did you have to broach a D into the end of the screw? That would be hard for me to do. Where do you get the acme shafts?

Sorry for the thread creep.

Jim

[dozerbuilder]

Originally Posted by Rvjimd

Dozerbuilder,

Thanks for the actuator info! Can't wait to see the plans! Not sure I understand the attachment from the D shaft of the motor to the screw? Did you have to broach a D into the end of the screw? That would be hard for me to do. Where do you get the acme shafts?

Sorry for the thread creep.

Jim

Hey Jim.

No broach, don't know how to use one. I'm just a bush mechanic having learned the trade over several decades working on big dozers in the coal mines here. To make the D in the shaft, drilled a 3mm dia hole dead centre in the end of the shaft centered in the lathe chuck, ground the acme thread off about a quarter of the diameter of the end to weaken it, laid it on an anvil and with a piece of heavy flat and a hammer, whacked it till the weak side formed the shape of the flat on the D to fit the motor shaft loosley. Pounded the thrust bearing (actually a roller bearing)on over the ground off bit.ACME Lead screws are on aliexpress

I've sort of unintentionally taken over sped74's thread, I will make a tech forum build thread for these soon. Sorry sped74. How are you getting on with yours anyhow?

[Sped74]

Originally Posted by dozerbuilder

I've sort of unintentionally taken over sped74's thread, I will make a tech forum build thread for these soon. Sorry sped74. How are you getting on with yours anyhow?

No Problem, this is great, thank you very much.

i think i need more help with like linkage and stuff to actually get my dump to function correctly

[Sped74]

[Sped74]

http://s1036.photobucket.com/user/sp...railer%20build

http://s1036.photobucket.com/user/sp...railer%20build

[TRUCKMAKER]

[Rvjimd]

Cool! Are you mig welding or brazing? That is 1/4" square stock right? I don't even have the gas setup for my welder but I would really like to try my hand at welding some AL. That trailer looks serious, I like it!

Jim

[Sped74]

having a guy at work TIG it. i'm the fabrication manager at a fab shop lol

[dozerbuilder]

Originally Posted by Sped74

No Problem, this is great, thank you very much.

i think i need more help with like linkage and stuff to actually get my dump to function correctly

Rolled up two more prototype barrels yesterday. Now we have a complete set all dims to 1/16th scale as per the original 1:1. These are what I'm calling MK2 prototypes. They work nicely, how long they will last in the motor connection is unknown, that's the weakness. So I'm working on that next. This will be my last pic here on your thread sped74, we need to get back to your neat dump body, but you can see now you can make your own.

[frizzen]

Sorry this wasn't showing up in your last post.

Great looking trailer

[dozerbuilder]

Originally Posted by frizzen

Sorry this wasn't showing up in your last post.

Great looking trailer

Ah thanks frizzen, don't know why. I could see an icon and click on it and get the pic. BTW, the trailer is commonly known as a Rear Mounted Quadrilateral-type Single-Shank Ripper.
(Edit: before had no pic, now we've got two! I dunno)

[frizzen]

I'm not sure how you embed them the way you were that doesn't display well, i just copy the pic url and threw it between a set of (img) (/img) tags. Change ( to [ and ) to ]

So it looks something like this:
(img)dozerbuilder.com/coolstuff.jpg(/img)