Industrial revolution of Crane machine

Industrial revolution of Crane machine

With the beginning of the Industrial Revolution,the first modern cranes were installed in ports for loading goods.In 1838,industrialist and businessman William Armstrong designed a hydro-hydraulic crane.His design used a plunger in a closed cylinder that was pushed down by pressurized fluid entering the cylinder,and a valve to regulate the amount of fluid intake according to the load on the crane.This mechanism, the hydraulic jig,then pulls the chain to lift the load.A scheme began in 1845 to provide piped water to Newcastle homes from remote reservoirs.Armstrong was involved in the scheme,proposing to the Newcastle Company that excess water pressure in the lower part of town could be used to power one of his hydraulic cranes to load coal onto barges in the docklands. He claims his invention does the job faster and cheaper than conventional cranes.The company agreed to his proposal and the experiment proved so successful that three more hydraulic cranes were installed in the dock area.The success of his hydraulic cranes led Armstrong to establish the Elswick factory in Newcastle in 1847,producing hydraulic machinery for cranes and bridges.His company soon received orders for hydraulic cranes from Edinburgh and Northern Railways and Liverpool Docks,and hydraulic machinery for the gates at Grimsby Docks.The company expanded from 300 employees and an annual production of 45 cranes in 1850 to nearly 4,000 workers producing more than 100 cranes per year in the early 1860s.Over the next few decades,Armstrong continued to improve his crane designs; his most important innovation was the hydraulic accumulator.Where hydraulic cranes are not available on site, Armstrong often builds tall water towers to provide pressurized water.However,when supplying cranes to New Holland in the Humber Estuary,he was unable to do this because the foundation was sand.He ended up building the hydraulic accumulator,a cast iron cylinder with a plunger that supports a very heavy weight.The plunger will slowly rise, sucking in the water, until the downward force of the weight is sufficient to force the water beneath it into the pipe under enormous pressure.The invention allows greater volumes of water to be forced through the pipes at a constant pressure,thereby greatly increasing the load capacity of the crane.One of his cranes was commissioned by the Italian Navy in 1883 and was used until the mid-50s and still stands in Venice today in a state of disrepair

Mechanics 

The design of the crane mainly considers three aspects.First,the crane must be able to lift the weight of the load;second,the crane must not tip over; and third, the crane must not break.

Stability

For stability,the sum of all moments at the base of the crane must be close to zero so that the crane does not tip over.In practice, the size of the load that is allowed to be lifted (called "rated load" in the United States) is some value less than the load that would cause the crane to tip over,thereby providing a safety margin.According to the American Mobile Crane Standard, the stability limiting load rating for crawler cranes is 75% of the tipping load.The stability limit load rating for mobile cranes supported on outrigger beams is 85% of the tipping load.These requirements, along with other safety-related aspects of crane design, are determined by the American Society of Mechanical Engineers in ASME B30.5-2018 Mobile and Locomotive Cranes Volume.The standards for cranes installed on ships or offshore platforms are more stringent due to the dynamic loads placed on the crane by the movement of the vessel. Additionally,the stability of the container or platform must also be considered.For cranes installed on a fixed base or main column, the moment generated by the boom, arm and load is borne by the base or main column.The stress in the base must be less than the yield stress of the material or the crane will fail.