A survey on the actuating force on brake and clutch pedal controls in agricultural tractor in use in Iran

IntroductionThe focus of farm tractor operator is on forward and reverse hydraulic arm's movements in addition to leg-pushing on brake and clutch pedals. Performing all these, with respect to the machine model and operator's position, determines the posture and the loading pattern of the operator's body.AimThe objective here has been the assessment of the pedal control to improve the operator's functionality.Material and methodsIn this study, 1500 operators were subject to close interviews by the researcher for 3 years in Isfahan Province. Operators with different anthropometries were involved by sitting on MF285, U650, JD3140 and JD950 combiner seats. The operator's knees were photographed in: free (no force enforcement), ready (beginning of force enforcement) and active (force enforcing) conditions. The thigh and leg angle at the knee joint was measured and the exerted force on the leg during leg-pushing was calculated too.Results and discussionAnalysis of the obtained data indicated that the MF285 tractor clutch exerted less maximum force on the knee due to the clutch mechanism. The JD3140 clutch needed more maximum force in relation to MF285. The least maximum force was exerted on the brake pedal of JD3140. Under operating conditions, the widest knee extension angle in leg-pushing was of the U650 and JD3140 tractors.ConclusionsThe U650 and JD3140 model tractors under ‘ready’ and ‘active’ conditions need less leg-pushing force. This force exertion from the knee occurs at the widest extension angle. These two models have higher ergonomic level with the least possible disturbance in the knee joint.