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A double extended octagonal ring (DEOR) drawbar force transducer is presented. This transducer utilizes two extended octagonal ring (EOR) transducers one located on each side of the drawbar to measure drawbar draft and vertical and side loads with minimum alteration of the tractorimplement hitch point configuration. Side loads are derived from the differential draft outputs of the two EOR's. The transducer was calibrated in a special calibration jig capable of simultaneously and independently applying draft, vertical, and side loads. The DEOR exhibited excellent linearity with draft and vertical sensitivities of98.0 and 94.8 J..lV Vol kN", respectively. Cross-sensitivity ranged between 2 and 7% of the primary DEOR output. Including cross sensitivity in the predictive force equations derived from mUltiple regression on 3-D calibration data compensated for this systematic error. The DEOR dynamometer was used to measure drawbar force components of secondary tillage tools in an on-farm research program. The portable device proved to be very sensitive, versatile, and suitable for measuring draft and moderate vertical and side drawbar forces exerted by most pull-type implement hitch configurations.
N.B. McLaughlin. S. Tessier and A. Guilbert 1998. IMPROVED DOUBLE EXTENDED OCTAGONAL RING DRAWHAR TRANSDUCER FOR 3-D FORCE MEASUREMENT. Canadian Agricultural Engineering 40(4):257-264.
Canadian Society for Bioengineering