Hitching and unhitching

Using either a category 2 or 3 linkage, the SM 310 requires two hydraulic services, one single-acting and one double-acting. The first controls the pressure on the cutterbar, while the second is used for folding/unfolding. Hitching and unhitching can be a bit involved and it’s important to get it right to avoid problems.

The pressure in the circuit has to be released before unhitching, so the operator needs to get out of the cab.

First, the single-acting spool is put in float position, with the other services in neutral. Once out of the cab, circuit pressure can be released by pressing a button on the cylinder.

A pressure gauge indicates the drop, and once it’s at the right level the operator has to get back in the cab to put the spool into neutral.

Folding

Two cables in the cab allow the driver to fold and unfold the mower. The black rope releases the safety mechanism on the main ram and the red activates the hydraulic valve to shift from work into transport position. A single-acting cylinder controlled by the second spool controls headland lift.

The mower can be transported in two ways: either vertically on the right-hand side of the tractor, or by unlatching the hitch and swivelling and moving the tractor slowly forward, it can be folded vertically in-line with the tractor instead.

Power transmission

A transfer gearbox transmits power via a shaft through a gear assembly which powers the cutterbar and conditioner. Each of the disc beds on the bar is driven by the main shaft running across the back of the beds. The transmission is protected by a slip clutch in case of any blockages.

Protection

If the mower hits an obstacle, it swings up and backwards thanks to a mechanical protection system. Two polythene blocks compress on hitting an obstacle, allowing the mower to swing back. It returns to working position thanks to gravity once it has passed the object.

Suspension

The cutterbar adapts to contours thanks to a hydropneumatic suspension system, controlled by a single-acting cylinder. The cylinder is attached close to the mower’s centre of gravity, allowing the operator to adjust the pressure from the cab using the single-acting spool valve.

Conditioner

The conditioner is driven using shearbolt-protected UJs. Unlike other conditioning units on test, the 2.2m rotor is fitted with spring tines, similar to those used on a tedder. Four rows of 12 double tines can be set to four different positions, and the gap between the plate and the tines can only be adjusted between 1cm and 3cm. To adjust the plate position, pull hard on the lever located by the pivot point on the front of the mower bed.

Swathing

To shift from spreading to swathing, there are two boards that need to be adjusted. This isn’t as easy as it could be, as it involves using a 17mm spanner to unscrew the bolts. There are four positions which adjust the width of the swath between 1.45m and 2.2m.

Cutterbar: Reduced maintenance costs

The mower bed on the Fella is made up of six disc beds, each carrying two knives and giving a total working width of 3.01m.

The knives are reversible, which cuts maintenance costs. The SM 310 tested didn’t have a quick change system, however that is an option.

The cutterbar is protected from foreign objects by a fin-shaped wear strip between the two discs, which can be removed by undoing four bolts. The protective skids can also be removed and replaced if worn.

Technical spec

Working width: 3.01m

Weight distribution: 140kg/200kg (inside/outside)

Number of cutting discs: 6

Conditioner speed: 900rpm

Price: £16,065

Likes:

Breakback suspension

Transport position

Mower bed protection

Gripes:

Awkward to release pressure before uncoupling

Two ropes needed

Limited conditioning settings