Shock absorber Sizing Examples Typical Shock Absorber and Crane Applications

Overview

Shock Absorber Sizing Examples Please note that this example is not based on any particular standard. The slung loadcan swing freely, and is therefore not taken into account in the calculation.

CalculationExample for Harbor Industrial cranes as Application 1

Total Weight of Crane:837,750 lbs.Weight of Trolley:99,200 lbs. Span:z = 3,940 in. Trolley Impact Distance:x = 3,540 in. Crane Velocity:V
Crane = 60 in./sec.Required Stroke:24 in. Trolley Velocity:V
Trolley = 160 in./sec.Required Stroke:40 in. Industrial bridge Weight per Rail = crane weight
total - trolley weight2Bridge Weight per Rail = 837,750 lbs. - 99,200 lbs. = 369,275 lbs.2W

Determination of theMaximum Impact Weight W

Dmax = Bridge Weight per Rail + Trolley Weight in Impact PositionW
Dmax

per BufferDetermine Sizeof Shock Absorber for Crane Determine Sizeof Shock Absorber for Trolley Given Values

Dmax = 369,275 lbs. + (99,200 lbs. • 3,540 in.)3,940 in. W
Dmax = 458,404 lbs. E
K = W
Dmax 772E • V
r2 V
r = V
A Application 1E
K = 458,404 lbs. • (60 in./sec.)
2 772
K = Kinetic Energy E
K = 2,137,635 in-lbs. η = Efficiency V Selecting for required 24-inch stroke: HD 5.0 x 24, maximum shock force ca. 104,786 lbs. = F
s = E
K s • η W
D = Trolley Weight per Shock AbsorberW
D = 99,200 lbs.2 W
D = 49,600 lbs. = V Application 1 E
r A K = W
D 772E •V
r2 K = 49,600 lbs.• (160 in./sec.)
2 772 E
K = 1,644,767 in-lbs. Selecting for required 40-inch stroke: HD 4.0 x 40, maximum shock force ca. 48,376 lbs. = F
s = E
K s • η
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