by GJ Stoltz (Reg Eng Tech)

The brief time available for getting the forage harvest done makes it vital to achieve high work rates. A multiple-rotor rake gets the job done faster than rakes with only one or two rotors.

We thank the ARC Agricultural Engineering in South Africa for making their manual on rakes and tedders available to the readers of ProAgri Zambia.

A rake can, for instance, be equipped with four rotors to speed up the raking process. The rotors are hydraulically controlled from the tractor cabin, enabling the operator to reach the peak of productivity with the least effort (see Figure 1). All the functions required in the field are controlled with the buttons on the control panel at the driver’s seat (see Figure 2).

The four rotors effectively double the work rate compared to the double rotor rakes. In one single run, they turn 12,5 metres of material into a uniformly shaped windrow laid in the centre of the machine. The working width is variable from 9,9 to 12,5 metres and the windrow width from 1,2 to 2 metres.

This big windrow can then easily be picked up by a baler or a forage harvester, chopped and blown onto a truck or a trailer (see Figure 3).

Hitching

The main frame of the rake is hitched to the two lower links of the three-point hitch system on a tractor. The articulated PTO-drive shaft enables the rake to make tight turns.

Rotors

Each rotor is supported by four guide wheels and has a fully floating suspension, independent from the chassis. This enables the rotors to take any ground contour in its stride (see Figure 4).

Land wheels

The four-rotor rake has two land wheels with high flotation tyres to reduce damage to the stubble and ensure good road travel characteristics. Some of these big rakes are equipped with hydraulic or air brakes that are controlled from the tractor. It all depends on the weight of the machine and legislation prescriptions (see Figure 5).

Transport

For transport purposes, the rotors can be folded upwards into a vertical position by means of hydraulic cylinders that will shrink the machine to a 3-metre width (see Figure 6).

Specifications:

This big machine is an important component in a high-performance forage harvesting system and it is also important to keep in mind that it can weigh as much as 4 140 kg. It requires a tractor of approximately 60 kW with a PTO-speed of 540 rpm.

It is possible to rake 8 to 10 hectares of lucerne per hour with this machine, but one must still be very cautious to prevent leaf losses that may occur if lucerne is handled too roughly.

Next month we shall discuss the rotary tedder and windrower.

Published with acknowledgement to the ARC Agricultural Engineering for the use of their rakes and tedders manual. Visit www.arc.agric.za for more information.