Self-Propelled Windrower

Overview

A self-propelled windrower, also called a swather, cuts standing hay or seed crop and lays it in a fluffy row called a windrow so it can dry in the field before baling or combining. It is a purpose-built machine rather than a tractor implement: the operator sits in a cab over a wide cutting header and drives the machine itself across the field. Putting the engine, drive, and header on one self-propelled unit makes for fast, precise cutting and the visibility to lay neat windrows, which is why large hay and canola operations use windrowers instead of pull-behind mower-conditioners.

The machine is built around a Tractor Chassis driven by a Diesel Engine through a Hydrostatic Drive system, with a wide Cutting Header up front to cut the crop and a Crop Conditioner behind it to speed drying. The operator runs everything from the Operator Cab, while the Hydraulic System and Electrical System systems power and coordinate the working parts.

Chassis, drive, and steering

The Tractor Chassis carries the whole machine on two front Drive Wheel units and two rear Caster Wheel units. There is no mechanical transmission or steering linkage: each front wheel has its own Wheel Motor, and the machine steers by driving one wheel faster than the other while the rear casters follow. This is the same idea as a skid-steer and it gives a very tight turn at the end of a pass. The Hydrostatic Drive system uses a Hydrostatic Pump for each wheel; tilting the pump swash plate sets that wheel's speed and direction, a Charge Pump keeps the closed loops fed, and a Control Valve ties the cab handle to both pumps so one lever both drives and steers.

Engine and cooling

Power comes from the Diesel Engine, a diesel Engine Block fed by a Fuel System with its own Fuel Tank and Injection Pump. Because windrowing throws dust and chaff, the Cooling Package package pairs a Radiator with a Oil Cooler for the hydrostatic oil and a Rotary Screen that self-cleans so the cores do not plug. The Air Intake uses a Pre-Cleaner cyclone ahead of the Air Filter for the same reason, and the Exhaust System carries a Particulate Filter to meet emissions limits.

The cutting header

The Cutting Header does the cutting. A Disc Cutterbar runs a row of Cutter Disc units, each spinning near three thousand rpm and carrying free-swinging Cutter Blade knives that shear the crop and fold back harmlessly if they strike a stone. The discs are driven in opposing pairs by an in-line Cutterbar Gear Train housed in the Cutterbar Bed, which rides the ground on Skid Shoe units that set the cut height. Above the cutterbar a Pickup Reel with tined Reel Bat units sweeps the cut crop rearward, and a Gathering Auger gathers it in from the ends. A Header Motor drives the whole header, and Header Lift Cylinder cylinders set its working height.

Conditioning and windrow forming

Hay dries faster if the waxy outer skin of the stem is cracked, so the Crop Conditioner passes the cut crop between two intermeshing Conditioning Roll units. A Roll Spring sets the squeeze: hard enough to crimp the stems, gentle enough to leave the leaves on, since the leaves carry most of the feed value in legumes like alfalfa. After conditioning, adjustable Windrow Shield panels form the crop into a windrow of the chosen width, wide for fast drying or narrow to feed a baler pickup, which is the operator's main field decision.

Cab, hydraulics, and electrical

The Operator Cab is an enclosed, rollover-rated Cab Shell with full Cab Glazing so the operator can watch both the header and the windrow. A Multifunction Handle sets ground speed, steering, and header functions from one grip, a Cab Display shows speed, header height, and engine data, and a Suspension Seat and Cab HVAC keep the operator comfortable over long days. The Hydraulic System system supplies the header lift and conditioner from a Implement Pump through a Valve Bank, and the Electrical System system ties it together with a Machine Controller that coordinates drive, header, and engine.

Use in the field

Self-propelled windrowers are used to cut alfalfa and grass hay, and to swath canola and cereal crops that are laid down to ripen evenly before a combine picks them up. Their speed and tight turning let one machine cut large acreage in the short window when the crop and weather are right, and the cab visibility lets the operator lay straight, even windrows that dry uniformly and feed cleanly into the baler or combine that follows. A windrower is reversible in concept with the header removed for transport, so the same chassis can carry different headers for hay or small grain, which spreads its cost across more of the season.