Retired engineer Dave Hundeby’s recent on-farm invention streamlines the effort of digging partially-buried large rocks out of a field, by blending a rock digger with a conventional rock picker.
While rock pickers take the sweat out of clearing fields of stones, they can’t handle every rock-picking job. Large, partially-buried boulders are beyond their capabilities and still need to be dug out some other way.
That is where this invention shines: it merges a rock digger and rock picker into one unit that can save time in the field.
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The attachment is capable of digging out very large rocks and carrying rocks up to three feet in diameter. It mounts directly onto a commercially available rock picker.
Other rock diggers on the market are usually designed as separate implements — so when an operator comes across a large buried stone, that means returning to the yard, unhooking the rock picker and going back out with a digger. But this invention streamlines that process down to one implement capable of both the picking and digging.
“There’s a synergy that happens when you fasten the rock digger to the rock picker,” Hundeby says.
Once a large rock is pulled out, the hole it leaves has to be filled in. The digger and picker combination makes that job easier too.
“You can use the grate of the rock picker and paddle as a bulldozer… scraping soil toward the hole and dumping it in. Then you back up and cut the tractor to the right, and the rear and front wheel of the tractor pack the soil you just dumped in the hole. If more soil is need, the process is repeated.”
Hundeby built the first digger attachment prototype in the spring of 2022 and mounted it to his Schulte reel-type rock picker. He has used it on his own farm near Saskatoon regularly since then, so it has logged a lot of use and he believes it has proven itself by saving time.
The digger attachment has now been patented in four different variations. The model Hundeby built pins to the rock picker frame on one side and has its own third wheel on the other. The tractor hitches to the digger, and the rock picker’s hitch tongue is pinned to the rock digger frame.
Another simpler variation in the patent eliminates the need for the extra wheel and allows the digger to simply be part of a rock picker frame using a rigid mounting system. The rigid-mount makes for a simpler, more compact design.
“In my opinion that would be the preferred (design),” he says. “So whoever takes it on (to manufacture commercially) could have two options. The machine could be sold as a combined rock digger and hauler — or sell the rock picker by itself, but the frame is ready for the rock digger attachment. Down the road an attachment could be purchased (separately).”
The digger could also be retrofitted to an existing rock picker a farmer might already have, by welding a suitable mounting bracket to the rock picker frame.
Once a rock is dug out of the ground, it can be released from the digger claw, then pulled into the rock picker hopper in the usual way if it’s small enough — or it can be carried directly to a rock pile and dumped there.
Hundeby has been using a 144-horsepower 4250 front-wheel assist John Deere tractor on the combination picker-digger unit, and he says the tractor has been able to handle the power and traction requirements without any problem.
As the inventor and patent holder, Hundeby says he’s interested in licensing the design to a fabricator or implement manufacturer for commercial production. Anyone interested can contact him directly via email at hundeby@sasktel.net.
