Telescopic Boom
The crane has a telescoping boom. This allows the boom to be extended or retracted, depending on the working height or the radius required to perform the lift.
Rubber Tracks
Tracks are used on spider cranes to manoeuvre the crane into position.
The use of rubber tracks allows the crane to be taken on many types of ground from muddy sites to load-sensitive floors.
They also allow the crane to climb stairs and ramps with ease.
Motor
Maeda mini cranes, or spider cranes as they are also known, can be fitted with motors powered with diesel, petrol or LPG.
The cranes can also be powered with an electric motor for zero-emissions and a low-noise operation, either indoors or outdoors.
Outriggers
Articulating outriggers (which have resulted in the machines being called spider cranes) act as stabilisers. They allow Maeda Mini Cranes to safely lift much heavier loads than their small size would otherwise allow.
Outriggers can be positioned in multiple configurations and lengths to allow the crane to work in the most challenging and restricted areas. Mats are placed under the outrigger feet to spread the load being transferred to the ground.
Hook
All cranes need a hook block. This device allows the crane to be adjusted and set up safely for the load it is required to lift.
The heavier the load, the more times the wire rope is passed through the hook block and back up to the jib-head from which the block hangs.
This method, using pulleys to exert greater force on a load so it can be lifted more easily, was first developed by the ancient Greeks and Egyptians.
Lifting Height / Working Radius
Cranes work in many different areas and no lift is identical to previous ones. Therefore, the crane has to be able to meet the needs of each and every lift it is being used for.
Lifting heights and working radius change every time, so operators have the ability to change the boom configuration to meet the requirement of every lift.
Operator Controls
Multi-function controls are part of every crane. Some cranes are available with remote controls so the operator can be positioned away from the crane to get the best view of the lift, improving safety and operational effectiveness. The latest cranes come with touch screen technology allowing the operator to see every aspect of the crane and its function. However most cranes still have levers and switches for operations.
Safe Working Load + Load Chart
Every mini crane must carry two clearly-visible signs. One gives its maximum safe working load (SWL). The other displays its load chart.A load chart provides data that defines each mini crane’s capabilities. The data can be used to calculate safe lifting capacities, depending on the distance the crane is from the load and the angle of the boom.
The information given by these signs is used by the crane operator to ensure the mini crane is always set up to carry out a safe lift. All cranes with a SWL over 1,000kg must be fitted with a LMI (Load Moment Indicator) or SLI (Safe Load Indicator).
At 95% of the SWL, an amber warning light comes on. At about 105% of SWL, a red warning light is activated. At this point, the mini crane’s function is automatically restricted. When this happens, the mini crane can only be operated in a way that brings the load back into radius, or lowers it off.
Slewing Ring
Most cranes come fitted with a slew ring. The slewing ring allows the crane to move the load through 360 degrees.