Crane Load Moment
Calculate a crane's load moment, M = W·R, from the load weight W (N) and the operating radius R (m, the horizontal distance from the crane's rotation center to the load). The load moment is the product of the load weight and its distance to the crane's rotation axis, and it GOVERNS the TIPPING stability — the most feared and catastrophic crane failure mode. A crane tips when the load moment (tending to overturn it forward, toward the load) exceeds the STABILIZING moment (the crane's own weight and counterweight, acting backward). The genius — and danger — is in the RADIUS: the SAME load generates a much larger moment when far (boom extended) than near (boom retracted). So a crane's capacity is NOT a single number, but a LOAD CHART that drops drastically as the radius grows — a crane lifting 50 tonnes at 5 m radius may lift only 5 tonnes at 30 m. Exceeding the maximum load moment (the 'load curve') is the main cause of crane tipping, so cranes have load moment indicators (LMI) locking operation near the limit. Computing the load moment and comparing it with the allowable moment for that radius is the fundamental safety check in every crane operation. Enter the load weight and the operating radius.
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Momento de carga do guindaste
O momento de carga de um guindaste é M = W·R, a partir do peso da carga W e do raio de operação R (a distância horizontal do centro de rotação do guindaste até a carga). É o produto do peso da carga pela sua distância ao eixo de rotação, e é o parâmetro que governa a estabilidade ao tombamento — o modo de falha mais temido e catastrófico de guindastes. Um guindaste tomba quando o momento de carga (que tende a virá-lo para frente, na direção da carga) supera o momento estabilizante (o peso próprio do guindaste e do contrapeso, atuando para trás). A genialidade — e o perigo — está no raio: a mesma carga gera um momento muito maior quando afastada (lança estendida) do que perto (lança recolhida). Por isso a capacidade de um guindaste não é um número único, mas uma tabela de cargas que diminui drasticamente conforme o raio aumenta — um guindaste que levanta 50 toneladas a 5 m de raio pode levantar só 5 toneladas a 30 m. Exceder o momento de carga máximo (a 'curva de carga') é a principal causa de tombamento de guindastes, por isso eles têm limitadores de momento (LMI) que travam a operação ao se aproximar do limite. Calcular o momento de carga e compará-lo com o admissível para aquele raio é a verificação fundamental de segurança em toda operação de guindaste. Informe o peso da carga e o raio de operação.
Related Tools
Wire Rope Safety Factor
Calculate a wire rope's safety factor, SF = breaking load ÷ working load, from the minimum breaking load (MBL, N) and the applied working load (N). Wire ropes, used in cranes, elevators, cableways, bridges, lifting and mooring, work with HIGH safety factors — far higher than static structures — for several reasons: the load is rarely static (there are impacts, accelerations, swings), the rope wears and loses strength over use (wires break, corrosion and fatigue occur), and a rupture is catastrophic (load drop, life risk). Codes prescribe minimum safety factors per application: typically 5 for general load lifting, 6-8 for people-carrying ropes (elevators, cableways), 3-4 for static stays and moorings, and specific values per use. The safety factor is the ratio between the load that would break the rope (its rated strength, from the maker) and the load it actually carries in service. Checking that the real safety factor meets the code minimum is the basic safety check of any wire-rope application — and the rope must be DISCARDED when wear reduces its strength enough for the factor to fall below the limit. Enter the breaking load and the working load.
Wire Rope Working Load Limit (WLL)
Calculate a wire rope's allowable working load, WLL = MBL ÷ SF, from the minimum breaking load (MBL, N) and the required safety factor. The working load (WLL — Working Load Limit, or SWL — Safe Working Load) is the MAXIMUM load that can be safely applied to a rope, fitting or lifting equipment — the information STAMPED on slings, shackles, hooks and equipment plates, and what the operator uses to decide whether a given load can be lifted. It is obtained by dividing the breaking load (the real strength that would break the component) by the code safety factor (5 for general lifting, more for special situations). Respecting the WLL is an absolute safety rule in lifting and material-handling: exceeding the working load dangerously approaches the component to rupture, eliminating the safety margin covering dynamic effects, wear and uncertainties. The WLL is not the rope's strength — it is the SAFE fraction of it. Every rigging operation starts by checking that the load to lift is below the WLL of each component in the load line (rope, slings, shackles, hook, eye), since the chain is only as strong as its weakest link. Enter the breaking load and the safety factor.
Linear Explosive Charge
Calculate the linear loading density of a blast hole, q = (π/4) × d² × ρ, from the hole diameter d (mm) and the explosive density ρ (g/cm³). The result, in kg of explosive per meter of hole, is how much explosive fits in each meter of charged column — a central parameter of rock blast design. Multiplied by the hole charge height, it gives the charge per hole; combined with the blasted rock volume, it gives the powder factor. Larger diameters and denser explosives raise the linear charge. Enter the hole diameter and the explosive density.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.