Mower Conditioner

Overview

A mower conditioner cuts a standing forage crop and crimps the cut stems in one pass, so the hay dries evenly and is ready to bale sooner. Grass and legume stems hold water far longer than the leaves do, and if the crop is only cut it can lie in the field for days while the stems give up their moisture. The conditioner solves this by cracking the waxy skin of each stem as it passes through, which lets water escape at nearly the rate the leaves lose it. The result is a faster, more uniform cure and a shorter weather window between cutting and baling.

The machine is a side-mounted implement pulled by a tractor. A Disc Cutterbar shears the crop at ground level, the cut crop is swept straight back into the Conditioner Unit rolls, and a Swath System lays it down as a wide spread or a narrow windrow. Power comes through the Driveline from the tractor power take-off, the Main Frame carries the head out beside the tractor track, the Float Suspension keeps the head pressing lightly and evenly on uneven ground, and the Hydraulics lift and fold the head for transport.

The disc cutterbar

The Disc Cutterbar is a low, sealed Cutterbar Shell that runs a row of oval Cutting Disc units in an oil bath. Each disc carries two free-swinging Disc Blade knives at its rim, and adjacent discs turn in opposite directions so the crop is sheared cleanly and carried toward the gaps between them. The discs are driven by a train of Helical Gear Pair spur gears inside the bar, riding on Ball Bearing spindle bearings, with a Skid Shoe under the bar to set cut height and slide over the field. Because a spinning disc that strikes a rock can wreck the whole gear train, each spindle sits on a Shear Hub that shears or splits to sacrifice one disc and save the rest. The blades themselves swing back on impact rather than snapping, and they are a routine wear item that operators replace in minutes.

The conditioner rolls

The Conditioner Unit is the feature that gives the machine its name. The crop passes between a Upper Conditioning Roll and a Lower Conditioning Roll whose chevron surfaces intermesh, held in time by Roll Timing Gear gears so the patterns mesh without the rolls touching. The Roll Pressure Spring springs load the upper roll down with enough force to crimp the stems yet let the roll lift over a thick slug of crop. A Roll Scraper keeps wet material from wrapping the rolls, the rolls turn on Ball Bearing journal bearings, and a Drive Belt carries power to them. Rubber chevron rolls suit legumes such as alfalfa, where they bend and crack the stems while shedding the leaves gently, while steel rolls or flails are chosen for coarse grasses.

Driveline and power

Power reaches the head through the Driveline. A telescoping PTO Shaft with two Universal Joint joints and a Shaft Guard links the tractor PTO stub to the Primary Gearbox, a bevel gearbox that turns the inline drive ninety degrees toward the bar. A Slip Clutch in the line slips above a set torque so a sudden jam cannot break the shaft or gears. From the gearbox a set of Drive V-Belt belts, kept tight by a Belt Tensioner, drive the cutterbar pulley, and a Drive Flywheel smooths the cyclic load as the discs cut in and out of the standing crop. The whole driveline is sized for the wide working width and the steady high speed the discs need.

Frame, suspension, and ground following

The Main Frame hitches to the tractor at the Headstock and carries the cutting head to the side on a Carrier Frame, offset so the tractor wheels run on the stubble rather than on the standing crop. A Swing Bracket lets the whole head swing rearward and ride up if it strikes a solid obstacle, then return to position. The Float Suspension is what keeps the cut even: Coil Spring float springs and a Float Link linkage on Pivot Pin pivots carry most of the head weight, so the bar presses on the ground lightly and follows dips and rises without scalping high spots or missing low ones. For the road the Transport Wheel casters and the Hydraulics take over.

Swath forming and use

Behind the rolls the Swath System decides how the crop lies. A Swath Hood funnels the conditioned mat, and a pair of Swath Board boards set wide throw the crop out in a broad, thin layer for the fastest dry, or set narrow gather it into a windrow ready for a baler or forage harvester. A Rear Curtain and Side Curtain curtains contain stones and stem fragments thrown by the discs. In use the operator chooses wide spread when the weather is good and a windrow when rain threatens or when a following machine wants a formed row. Mower conditioners are the standard first step in modern hay and haylage work, taking the place of the older mow-then-rake-then-condition sequence by cutting and crimping in a single pass at field speeds of ten to fifteen kilometres per hour.