The Mechanics of Cranes

01st March 2019

Have you ever seen cranes lifting heavy materials and wondered just how they do it? Comparatively skinny mechanical arms are capable of lifting over hundred tonnes during building construction. While impressive, cranes work by making good use of some basic scientific principles to carry out their important work.

Mobile crane trucks are increasingly common due to the benefits mobility offers for everything from construction and electric line maintenance, to lifting heavy furniture into second storey homes. Mobile cranes can move in various directions as well as travel on public roads, avoiding the need for additional transport equipment.

How Cranes Lift

Cranes can achieve powerful lifting capabilities in many ways. The first is the lever, used in balance style cranes. These types of cranes are common seen as the tall fixed structures used to build skyscrapers. They work by balancing the crane’s beam at the fulcrum, allowing it to lift heavier objects with a smaller amount of force.

Jib style cranes use pulleys to achieve a mechanical advantage. Mobile cranes feature several hydraulic cylinders which control the motion of the crane as well as other mechanisms. These components are subjected to large forces when handling heavy loads.

Hydraulic Arms in Mobile Cranes

Hydraulics work through the transmission of force between points through a fluid. The fluid used is incompressible, meaning its already at its maximum density. The fluid used in hydraulic arms is typically oil. When a piston applies force downwards, it pushes the fluid against another piston, driving it up the opposite direction with all of the original force.

A pump creates that necessary pressure, with most hydraulic cranes using a two-gear pump to pressurise the oil. The force created allows the arm to carry huge amounts of weight. The focused strength is capable of picking up anything from steel bridge beams to concrete cylinders. Hydraulics are also used to power a range of other technologies such as car brakes and garage jacks.

Other Key Components

Of course, there are other important components that make a hydraulic crane functional. This includes the boom, which extends the arm in the desired direction to lift the load, and a hook, which is used to pick the load up.

Another important part of mobile cranes is the stabilisers. These involve legs that come out on either side of the crane truck to offer additional support for the weight of the load and to reduce the risk of the crane truck tipping.

Crane Hire – Brisbane and Gold Coast

Do you need to hire a mobile crane for a domestic or commercial job? Surf City Cranes offer a variety of quality crane trucks for hire on the Gold Coast, Brisbane and Ipswich. Ask our friendly experts about our different cranes and their capabilities and accessories. Call us today on 0421 665 654 or 0402 269 535 or contact us online.