The Arnal Brothers, Clifford and Clarence, Ravenscrag, Saskatchewan, say the idea behind their major overhaul of a commercial rock picker was to streamline a tedious and never-ending task.
The Arnals, with help from Clifford's his five sons, farm what they claim is some of the rockiest soil in the world. They spend weeks every year clearing rocks from fields.
When they went shopping for a rock picker they felt that the Harley rock picker, made by Harley Enterprises of Clarissa, Minnesota, was closest to what they wanted. As heavy and well-built as it was, though, it wasn't good enough. So they proceeded to beef it up fit their needs.
The hopper on the Harley picker holds a cubic yard of material. The Arnals use 3-ton dump trucks with 2-ft. sides to haul stones away from the rock picker and it would have taken four or five hoppers to fill a truck. They wanted to dump into each truck just once, so they rebuilt the hopper to hold 4 1/2 yards. "That's about all a 3-ton truck will hold," Clifford notes.
Because of that change in the hopper, the axles and frame on the original rock picker were no longer adequate. The original design had two fixed axles with single wheels. They changed this to a walking tandem with two sets of duals on each side of the rock picker. They lengthened the frame and the feed conveyor to give it more capacity, but it still has the original tumbling cylinder that separates soil from the stones.
They left in place the second conveyor that moves rocks from the cylinder to the rock hopper, but added a paddle to help move the rocks off the conveyor into the hopper.
They had to design a new scissors-type lift in order to pick up and dump the enlarged rock hopper. They added two 4 ft. hydraulic cylinders, one mounted on either side, between the lift frame and the main frame near the axles to raise the box high enough to dump into a truck. A second set of smaller cylinders tips the hopper to dump it.
Clarence says they can use the rock picker behind a tractor as small as a 4020 John Deere, but notes that on sloping ground, it's better to have something bigger because of the weight of the rocks when the hopper is full.
Before using the rock picker, they windrow rocks with either a tooth rake or a roller rake, depending on the size of rocks in the field. After windrowing, they pick up the largest rocks with a fork-type picker. "The modified picker will handle stones up to about 14 in. in diameter," Clifford says. Once it's rolling, the big rock picker will fill up in about 5 minutes and it takes just a minute to dump it into a truck.
"If you have enough trucks, you can clear a lot of land in a short time," he says. The Arnals have hauled as many as 100 truckloads of rock in a day using the modified picker and two trucks.