Rock Windrower

Overview

A rock windrower clears loose stones from a field by raking them into a single long row, a windrow, that a separate picker or loader can then collect in one pass. Stones work up to the surface every year through frost heave and tillage, and a field full of them dulls tillage tools, jams harvesters, and damages tyres. Hand picking is slow and back-breaking; a windrower lets one tractor sweep a wide swath, flick the rocks out of the soil, sift the dirt back out, and leave a clean row ready for pickup. The machine is a wide spring-tine reel working just below the surface, backed by a grid that separates rock from soil.

The implement combines the raking Raking Reel, a separating Separating Grid, a folding Main Frame, a PTO Driveline from the tractor, a Depth Control to set how deep the tines run, a Hydraulic System for wing folding, and a Three-Point Hitch to the tractor.

The raking reel

The Raking Reel is the heart of the machine. A central Reel Shaft carries several Tine Bar bars, and each bar holds a long row of Spring Tine coiled fingers clamped on by Tine Clamp clamps. As the reel spins, the tines sweep down into the top of the soil, catch stones, and flick them up and back. The tines are spring steel so they whip rocks free yet trip and spring back when they hit a fixed boulder or root rather than snapping. The bars tie into Reel End Disc end discs that turn on Ball Bearing mounts. Tines are wear items: they round off and break against abrasive ground, so they clamp on individually for quick replacement.

Separating rock from soil

Behind the reel sits the Separating Grid, the part that makes the difference between a windrow of clean rock and a windrow of rock mixed with good topsoil. The reel throws everything it lifts, stones and soil together, onto a sloped bed of spaced Grid Bar bars held in a Grid Frame. The gaps are sized so that dirt and small pebbles sift straight back down to the field while pickable stones ride over the bars. A curved Rock Deflector then guides the rocks off the end of the grid into a single tidy row. The grid bars and the Wear Shoe skids beneath them are hardened, since they ride in constant grinding contact with stone and abrasive ground.

Frame and folding

The Main Frame carries the working parts across a wide swath and folds down for the road. A box-section Main Beam is the spine, and two Folding Wing sections extend the working width. Each wing pivots on a Wing Hinge so the machine can be folded under three metres wide for transport between fields, then unfolded to its full working width in the field. Sheet Metal Panel shrouds keep thrown stones contained, and a Fastener Set holds the structure together. Folding matters because a useful working width is far wider than any road allows.

Driving the reel

The reel is spun from the tractor through the PTO Driveline. A PTO Shaft takes power from the tractor power take-off into a Gearbox Housing whose Helical Gear Pair bevel set turns the drive across the machine, and a pair of Drive Chain roller chains carry it out to the reel sprocket. A Slip Clutch protects the line: when the reel locks on a buried boulder the clutch slips instead of shearing the shaft or stripping the gears. The gearbox runs in oil behind two Oil Seal seals on four Ball Bearing units. Tine speed is set to match ground speed so the reel sweeps cleanly without throwing rock too far.

Depth control

How well the machine works depends on running the tines at the right depth, and the Depth Control sets that. Several Gauge Wheel wheels roll on the surface and hold the reel at a fixed height, adjusted through Depth Link links. On soft or uneven ground a pair of Depth Skid skids limit how deep the tines can dig. Too shallow and the reel skips over half-buried stones; too deep and it loads itself with soil and bogs down, so depth is set carefully for each field, all on Ball Bearing gauge wheel mounts.

Hydraulics, hitch, and use

The Hydraulic System fold the wings and lift the reel from the cab. Two Fold Cylinder rams swing the wings, a Lift Cylinder raises the reel clear at headlands, and a Control Valve splits tractor oil between them through a Hose Set, sealed by an O-Ring Set. The Three-Point Hitch mounts the implement on a Hitch Frame A-frame with Lower Link Pin and Top Link Pin pins, and a Parking Stand holds it when parked. Rock windrowers are used on stony fields before planting, often paired with a rock picker that follows the windrow: the windrower gathers a season of surfaced stones into rows, and the picker lifts them clean in one slow pass, leaving the field workable.