DIY 12 volt trailer tugger

[TimC-TNT]

I've decided to pursue a project that will help me get my trailers out of my back yard so I don't have to drive across my yard anymore. I see a few online examples of DIY tuggers made from a typical manual trailer dolly such as this...

I am less than impressed with the one I have and doubt the wheels and frame would stand up to the torque of a drive motor pulling my trailers (700# and 1500#). The tires/wheels being cheap and with little tread are not really made for pulling so I would have to upgrade the wheels. Instead I think I will start from scratch. I'm not much of an engineer so I will ask a few questions to get a start on this thing.

The drive motor will be a small 12v winch (lose the cable and add a sprocket and chain) that will drive the axle. I don't think I need a separate battery since my trailers already have a batteries installed and I can just tie into that circuit off the battery (properly fused of course). My question before I start designing this thing... should the tugger have three wheels to assist steering? Or is one axle/two wheels sufficient to allow steering? And if three wheels is best should the coupling ball be mounted in the center of that triangle?

I'm guessing I will need to add some extra weight to the rig to give it proper traction. And the frame will be plywood and lumber since I don't weld. Anyone tried something like this? I know there are tuggers out there for $250 and up that would do the job. I prefer to DIY this thing.

 

[olddawgsrule]

I do love a project! I'd go 3 wheels. I just think of my dolly for boxes and handling/balancing those loads being well under what you'll be dealing with. Also thinking steering.. I see the steering solo wheel closest to you and the ball with less weight on it. Ball I see as placed much like your trailer axle, 1/3 rule or less. Should place just enough weight to steer and not dig into the ground.

Of course all that wheel placement will be tossed once you add the torque of the motor.. Might be useful to put that 3rd wheel in a slot, unistrut comes to mind.

Interesting project!

My go to site for engineering: The Engineering ToolBox
I'm certain there's a formula in there.

 

[KCStudly]

I think the 2 wheels on one axle would be better, so long as you have adequate leverage in the handle to keep the wheels from driving out from under the ball.

Me? I'd just rig something to the hitch point on my garden tractor.

In fact, you might want to look at garden tractor transmissions on market place or somewhere used. Having a variable speed transmission with differential axle would be a good starting point. Cable winches typically have short duty cycles and high current draw... you might easily overheat (or trigger thermal protection) and/or quickly discharge your battery if moving any significant distance. something to think about, anyway.

 

[Pmullen503]

In fact, you might want to look at garden tractor transmissions on market place or somewhere used. Having a variable speed transmission with differential axle would be a good starting point.........

https://www.surpluscenter.com/Power...ward-Transaxle-w-Pull-Brake-Lever-13-1621.axd

 

[TimC-TNT]

Thanks guys. I can always count on you'se guys to set me in the right direction...

I had a lawn tractor but sold it several years ago. Dang! I've watched a guy modify an old snow blower. Too much welding requirements there but a good idea for someone who welds. I think you are right that the continuous load on the winch motor, even the five minutes I'd need to pull it to the driveway, would probably stress the motor beyond its capability. I'll keep drawing up plans and see what I come up with.