The tractor leaves long swathes of hay in its wake. It pulls a hay tedding machine which turns and loosens the hay.

A hay tedding machine consists of several arms rotating about a top. Large rakes on the arms grip the hay on their right side and release it again on the left side.

The hay tedding machine is driven by the tractor via a power take-off shaft.

The tractor pulling the hay tedder drives the top with the large rakes via a power take-off shaft. The rotary motion of the shaft is transmitted to the top via a bevel gearbox.

The swivel motion of the rakes is controlled by track rollers running on a track about the centre point of the device.

There is also an adjusting shaft which allows the tractor driver to adjust the height of the unit.

The requirements on the bearings are typical of those placed on bearings used in agricultural equipment:

• shock-type loads

• rough treatment

• severe contamination

• moisture

• long stationary periods, for example in winter

• long periods of operation, when large quantities of hay need turning.

During periods of operation, the bearings must operate with practically no maintenance. They must also operate reliably.