Slide 1Slide 2Slide 3Horizontal Movement, Push/PullSlide 5ENERGY COST OF WORKEx. #1: Box LiftingEx. #1: Box Lifting – con’tEx. #1: Box Lifting – Total ĖSlide 10IE 5531IE 553 Engineering of Human WorkDr. Andris FreivaldsClass #29IE 5532Garg’s Model (metric)Posture, lifting/loweringIE 5533Walking, carrying, holdingIE 5534Horizontal Movement, Push/Pull•X = horizontal distance moved•F = push/pull force (friction)IE 5535Type of work (Lehmann, 1950)↑ kcal /minLight hand work (writing, keying)0.2Heavy hand work (assembly, lathe)0.6Light work, 2 arms (filing, planing)1.2Heavy work, 2 arms (hammering)2.2Lateral Arm/Hand WorkIE 5536ENERGY COST OF WORKIE 5537Ex. #1: Box Lifting 70 kg male, lifting 10 kg boxes, 10/min, from 0.76 m bench to 1.01 m conveyor1) Stoop lift 0.76 m → 0.81 mΔE = 10-2[0.325BW(0.81-h1) + (1.41L + 0. 76 S×L)(h2-h1)]ΔE = 10-2[0.325(70)(0.05) + (1.41(10) + 0. 76(10))(0.05)] = 0.022 kcal/lift2) Arm lift 0.81 m → 1.01 mΔE = 10-2[0.062BW(h2-0.81) + (3.19L - 0.52 S×L)(h2-h1)]ΔE = 10-2[0.062(70)(0.2) + (3.19(10) - 0.52(10))(0.2)] = 0.062 kcal/liftIE 5538Ex. #1: Box Lifting – con’t3) Arm lower 1.01 m → 0.81 m (no load)ΔE = 10-2[0.093BW(h2-0.81) + (1.02L + 0.37 S×L)(h2-h1)]ΔE = 10-2[0.093(70)(0.2)] = 0.013 kcal/lower4) Stoop lower 0.81 m → 0.75 m (no load)ΔE = 10-2[0.268BW(0.81-h1) + 0.675L(h2-h1)+5.22S(0.81-h1)]ΔE = 10-2[0.268(70)(0.05) + 5.22(0.05)] = 0.012 kcal/lowerStanding posture Ė = 0.024BW = 0.024(70) = 1.68 kcal/minIE 5539Ex. #1: Box Lifting – Total Ė Ėjob = [∑Ėposture × time + ∑ΔEtasks] / time∑ΔEtasks = 10×[0.022 + 0.062 + 0.013 + 0.012] = 1.09 kcal Ėjob = 1.68(1) + 1.09 = 2.77 kcal/minIE 55310HW #860 lbs7.5
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