Design and performance of an adjustable three-point hitch dynamometer

Mounted implements necessitate the use of a three-point hitch dynamometer to measure the forces between the tractor and implements. In this work, an adjustable three-point hitch dynamometer was designed to fit most of the implements (standard and non-standard) available in Jordan. The dynamometer consists of three telescoping beams connected to a central T-shaped box. The system provides variable width and height of the dynamometer to satisfy a wide range of implement dimensions. Strain gages attached to cantilever beams were connected to a Wheatstone bridge in such a manner that only draft force is measured. The dynamometer was calibrated and several field tests were conducted to measure the force required to pull a chisel plow in a Jordanian clay loam soil at various depths and speeds. Different sets of strain gages can be attached and arranged in the bridge so that only the lateral or vertical forces can be measured.