5 September 1997

Checks make sense

Preventive maintenance helps keep potato harvesters working without a hitch.

Mike Williams went to Lincolnshire to find out what routine checks are needed

MAINTENANCE standards have improved considerably within the potato harvesting sector. But some growers still put up with breakdowns which could be avoided by spending just a few hours checking the harvester before and during the lifting season.

That is the view of Stuart Smith, technical specialist with Grimme UK. "Checking the machine over can help to reduce the risk of an accident as well as improving the reliability. It doesnt take very long, and its the sort of job that can be fitted in on a wet day as well as when the pressure is off during the winter."

A demonstration of the checks needed was provided by Tommy Cook who operates a Grimme Variant DL1700 harvester for the Glentworth Bulb Co at Owmby Cliff Farm, Lincoln. The harvester, now in its third season, lifts about 140ha of potatoes a year, including 30ha (346 acres) of contract work, and it also harvests 10ha (25 acres) of onions.

Thorough pre-season health checks are an important part of the farms machinery maintenance policy. After 10 years with various Grimme harvesters Mr Cook knows his way around this type of machine.

His routine starts with safety. If the harvester is hitched to a tractor the first job is to remove the key. Safety points covered on the harvester include checking the pto guard for damage and then the various safety guards covering drive mechanisms and other moving parts.

This is not as straightforward as it sounds. The screw type latches which secure the guards must all be working properly and are tested individually with a screwdriver.

Mr Cooks harvester has an optional picking table which means extra guards to check.

The Variants hydraulic components are next. There are two indicator dials to show the condition of filters – the usual one for the RS separator drive system plus a second one for the hydraulic drive to the optional powered wheels on this machine.

Mr Cook says these need checking at frequent intervals during the season as well as the pre-season check. "It is cheaper to change a filter than have a major breakdown in the field." A third filter, for the oil from the tractor hydraulics, is changed annually.

Hydraulic system checks also include examining pipes and connections for leaks or signs of damage due to chafing.

Maintaining the correct tension of drive chains is another job which starts with a pre-season check and continues through the harvest.

The drive mechanisms on the Variant include three gearboxes which need more than an annual check.

Another drive mechanism to be checked is the bank of four vee belts which deliver the power from the tractor pto. To simplify the maintenance routine there is a slit in one of the guards so a screwdriver can be inserted to check the tension. An inspection hole allows visual checks on the belts.

Checking the lifting and separation mechanisms starts with the share blades. Wear to the webs and joiners also needs watching. "It is easy to fit a new web in the workshop, but much more difficult in the harvest field."

Each steel haulm feeding finger has a rubber sleeve which should be checked carefully – both before and during the season. If a sleeve is damaged, the rough edge can get tangled with the haulm, and exposed metal on the fingers can damage the potatoes.

Next in the checking sequence are the smooth haulm roller and the star rollers. These are examined for excessive wear which could increase potato damage and losses.

Damage to the rubber covering on the RS rollers can also allow potatoes to squeeze through gaps. The rollers should be checked visually from above and below. Getting beneath the rollers also allows the setting of the scrapers to be checked.

Grease points need attention before and during the season. This is easier than it used to be, says Mr Cook. "Sealed bearings on the latest harvesters make the job much easier."

When replacement parts are needed have the information from the machine identification plate ready, advises Mr Smith. "The plate gives the production year and the serial number, and if you quote this information when you order it helps to make sure you get the right parts."

HARVESTER CHECKLIST

&#8226 Pto guard

&#8226 Safety guards

&#8226 Hydraulic filters

&#8226 Hydraulic pipes and connections

&#8226 Drive chains

&#8226 Drive gearboxes

&#8226 Drive vee belts

&#8226 Share blades

&#8226 Webs and joiners

&#8226 Haulm feeding finger

&#8226 Haulm roller

&#8226 Star rollers

&#8226 Scrapers

&#8226 Grease points

CHECKLIST

&#8226 Pto guard.

&#8226 Safety guards.

&#8226 Hydraulic filters.

&#8226 Hydraulic pipes and connections.

&#8226 Drive chains.

&#8226 Drive gearboxes.

&#8226 Drive vee belts.

&#8226 Share blades.

&#8226 Webs and joiners.

&#8226 Haulm feeding fingers.

&#8226 Haulm rollers.

&#8226 Star rollers.

&#8226 Scrapers.

&#8226 Grease points.

Maintenance saves harvest delays, say Stuart Smith of Grimme (far left) and Tommy Cook of Glentworth Bulb Co, Lincs. Checks such as gearbox oil level (above) need doing more than once a season to avoid downtime.