Towable All-terrain Pallet Jack

I live in a house that uses an open fireplace as the main source of heat. We have plenty of firewood from fallen trees and limbs, but moving it from the wood pile to the house is a constant daily task using a wheelbarrow. I thought that a system of stillages that could be loaded at the wood pile and then moved to the house would be a good solution.

We have a tractor with lifting forks, but this is not suitable to be driven across the lawns to deliver the stillages of wood to somewhere near the house. I checked out a few Instructables on putting forks on the 4-wheel ATV but a quick test showed that the suspension modifications were going to be extensive and complicated. I decided the best solution was a trailer that could function as a pallet jack. To pick up the stillages the trailer can be manually maneuvered. To transport from the storage area to the house, it can be hitched to the ATV.

Some quick research showed that rough terrain pallet jacks rely on two long arms to put the load-bearing wheels near the centre of the load. This means the load width is constrained by the width of the space between these arms. I decided to go for a 1m wide load, with a nominal depth of 600mm. Most logs are 450mm, but can be up to 540mm as that's the size that fits on the splitter.

In writing this Instructable, I'm not attempting to teach you to measure, cut, drill or weld. If you can do those things then you'll be able to build this machine fairly easily. My approach for this project has been to construct an evolving prototype and see if it works as a time saver. I didn't worry too much about getting everything perfect, but rather chose to see what breaks or could be improved, and then return to reinforce or redesign the parts that break or don't work well. Spoiler alert: it works well, and I've already made several improvements.

I mostly constructed this from leftover bits of steel, but I did buy a few things, too.

Steel:

50x50x2 SHS, 40x40x1.2 SHS, random gal tubing 50-75mm RHS, various bits of angle, 6 and 8mm thick. You could probably substitute lots of different tube or angle sections, my choices were based on what was lying around.

Fixings and sundries:

Some M8 x 25mm galvanised bolts, one M10 x 150mm galvanised bolt, rust converter paint, grease.

Purchased items:

250mm trolley/hand-cart wheels with 16mm axle

Towing hitch for 50mm towball

Solid rubber trailer jockey wheel with jacking screw

1500kg bottle jack, 220mm lift

All of the purchased items were around $50AUD each, with some advanced planning I could have gotten better deals online, but I purchased them at local retailers.

Tools:

MIG Welding machine with 0.6mm mild steel wire and Argon/CO2 gas mix.

Angle Grinder

Plasma Cutter

Stand drill

The idea was to build a chassis that partially surrounded a square load sitting on a stillage. This would place the wheels slightly behind the centre of gravity of the load. A trailer hitch extending forwards would allow the chassis to be towed and a 360-degree rotating jockey-wheel would support the load when maneuvered manually. The lifting forks would sit in between the wheels, and a manual hydraulic bottle jack would provide the lifting force. The load would need to be lifted at least as high as the axles of the wheels to provide clearance over rough ground.

I had some tubes welded into a 'U' shape that I'd recovered from our cattle yards, this had an internal width of about 1050mm, which would be perfect for the main chassis. I later discovered this steel was very soft and the big tube at joining the two arms was quite thin-walled, so some re-inforcing was needed, but I won't waste too much time on that as I'd recommend using something a bit stronger, like 50x50x2 SHS. I wanted the frame to ride about 250mm off the ground, so I welded two legs to take the axles for the wheels. I had intended to put a diagonal brace on these legs but didn't get around to it, and they don't seem to need it. Some left over tube with an internal diameter of 16mm was welded onto the bottom of the legs as axle carriers.

The tow point for the 4x4 is quite a long way under the rear load deck, and our existing trailer has a very long hitch, so I decided to make the hitch tube about 1m long which works out well when you are manually steering the jack and gave me enough space for the jockey wheel and jack. The frame ended up being a kind of squared-off 'Y' shape.

I decided to use an 830mm fork width which was copied from the tractor forks. I chose to make them a bit longer than the planned 600mm load depth for some more versatility. I used some very light 40mm SHS steel that had come as a disposable pallet with some fencing on it. I expected this would be too light and would need re-enforcing but I had it on hand. I welded the forks to the ends of a tube at right angles. I then created an A shape vertical frame attached to the forks. This would provide the jacking point for the bottle jack at the centre and transfer the load efficiently from the horizontal forks.

I had not really worked out the geometry of the fork system yet, I figured I was going to have some sort of track welded to the fork A-frame, and then some sort of guide welded to the chassis to keep the forks steady, while the bottle jack provided lifting force to the centre of the A-frame. I wanted the forks to tilt a little as the load comes up so the load would tend so sit hard against the A-frame, and is less likely to bounce free during transport. After some sketching of various arrangements, I realised the best way to achieve this is to have a long arm pivoting from a long way up the towing hitch and attaching to the top of the A-frame. This would give the forks a slight tip forward as they were raised, and by using a thick square section and heavy cheek plates at both ends, it would provide some stabilising effect to the forks to keep them level. The forks would have two vertical guides inside the depth of the frame to prevent them from slopping around in case the loading was eccentric. Thes tracks would need to be slightly curved to cope with the tipping of the forks during the lift, but nothing was too accurate, so I decided to simulate this with two straight sections.

I spent some time playing around with the mounting of the lift jack, eventually deciding on a plate that sat on a bolt as a pivot. I changed the jack controls a little to add a permanent up/down valve handle and to offset and permanently attach the lift handle. I made the control arm pivot points on the hitch tube adjustable while I experimented with the loading/lifting. This was made a bit tricky be the slow but steady failure of the thick main tube which turned out to be very weak. rather than replace it I stiffened the corners and hitch connection with some scrap angle, which seems to have worked. I probably should get some new tube and replace that part of the frame, but it's working for now. Likewise the A-Frame guides need a bit of tweaking and greasing. They are a bit more agricultural than I'd like, but again, they seem to work. I bolted on the towing hitch, and screwed on the jockey wheel. This second method wasn't going to last but I wanted to test the operation and ground clearance before doing some more elaborate fixing.

Once the jack was working I built a timber stillage with a pallet floor and a back fence, with two struts forming side barriers. Logs can be stacked on the floor against the back fence. I used recycled timber to keep it simple and cheap. Once I had proved the concept, I built a steel tube stillage that is lighter and easier to use. I intend to make a few more of these. The advantage of the system is that dry timber can be stacked onto the stillage, transported with the jack, and dropped at the house to be used. Meanwhile, the empty stillage is returned to the yard for loading. I have found it is most efficient to do all the jobs in one go, so when I return the stillage I reload it then and there and leave it with a cover ready for the next change-over.