Harvesting System Design and Performance - Engineering and Science of Biomass Feedstock Production and Provision - page 89

a

2

b

a

1

c

b

Fig. 5.4 ( a ) Types of sickle bar cutters: (a) finger bar with lip, (b) finger bar without lip, and (c)
dual-action cutter bar. Adapted from [ 19 ]. ( b )Constructionaldetailsofatypicalcutterbarsection.
Adapted from [ 16 ]

speeds(8-9 km h −1 ). The dual oscillating elements either have dual oscillating
knives (see Fig. 5.5B 1 ) or an oscillating knife and an oscillating finger bar
(see Fig. 5.5B 2 ). The oscillating knife and oscillating finger bar type (see Fig. 5.5B 2 )
are more robust and better suited for cutting crops close to the ground, whereas the
dual oscillating knives type (see Fig. 5.5B 1 ) is vulnerable to soil and rocks because
it is not protected by the guards.

5.3.1.2 Vertical Axis Rotary Mowers

Vertical axis mowers avoid many of the complications of reciprocating mowers.
They cut the crop with freely pivoting blades attached to the rotating disks
(see Fig. 5.5c, d ). The pivoting action of the blades allows them to freely swing
away from rocks and other obstacles. In all rotary mowers, the crop is unsupported
during cutting. For a clean cut, the cutting force must be absorbed by the rigidity of the