OFFSET AND TANDEM DISC HARROW

Offset disc harrow is commonly employed as secondary tillage implement but occasionally adapted and it is adjustable to suit primary tillage operation. An offset disc harrow is made of two gangs of concave discs which are operating in the tandem. The front gang of the concave discs moves the soil to the right while the rear gang of concave discs moves the soil to the left.

Unlike the offset disc harrow, the tandem disc harrow is much more of a secondary tillage implement and it is usually with four or more gangs of discs and smaller concave discs than the former. Basically, the tandem disc harrows consist of the front single-acting disc harrow and two rear gangs of concave discs operating in it. The front single-acting disc harrow of rear gangs throws the soil outward of the centre of the tilled strip while the rear gangs of concave discs throws the soil towards the centre of the tilled strip.

The trailed disc harrow is usually equipped with transport wheels and control hydraulic cylinders permitting the harrow to be lifted off the ground for turns. A disc harrow is made of a number of component parts which include concave discs, disc gangs, frame, standards, bearing, scrapers, weight boxes, bumpers and leveling devices.