Smart and safe cranes

When it comes to smart cranes, safety, emissions, and vehicle and operator productivity are vital to the health of construction companies, crane operators and the environment.

Developing cranes that are safe, smart and easy to operate helps reduce crane accidents, injuries and deaths, downtime and damage to the crane itself as well as the surrounding project area. If a crane tips over at a construction site, the damage to the site and the consequential downtime can cost millions of dollars. More subsystems and electronics that constantly monitor and control the many phases of crane operations help make improvements to safety and ease of operation.

A ‘smart’ network of sensors, switches and controllers can automatically alert and resolve problems before a danger becomes imminent, rather than relying solely on the instincts of a crane operator.

When it comes to emissions, a network of sensors and sophisticated electronics monitor the engine and hydraulic operations of a crane to ensure that all the systems are operating at maximum efficiency. As the overall crane operation is optimized and runs more effectively, less time and overall energy is needed to complete a task or project. If a crane can finish a complex task in five hours versus seven, for example, less fuel is used and harmful by-product emissions are reduced.

A closer look at a smart crane

A smart crane can use a diverse range of sensors and switches to provide safety, efficiency and higher accuracy for crane movement and load placement (see illustration on page 23). For example, at the top end of the crane boom, a hook load sensor (sensor 22a) measures the weight of what is being lifted to ensure that it does not surpass the crane’s safe operating specifications. A similar type of load switch (sensor 22b) is used on the outriggers used to stabilize the crane on rough ground, ensuring that the crane is evenly balanced and will not tip over.

Temperature sensors measure the temperature of the various oils and fluids used to operate the crane to prevent overheating and system failure (sensor 2), while a similar temperature sensor located in the cabin (sensor 1) ensures that the operator is working in a pleasant climate.

Limit switches are found in most cranes, and are used to measure and sense position—more specifically when a moving part has reached its defined operating limit. The limit switch that measures the jib and boom extension (sensors 17 and 18) helps to reduce the possibility of the jib and/or the boom being extended too far, which could cause the boom to be damaged during a lift or even topple over.

To ensure that there is an adequate amount of gas, oil and brake fluid to continue safe operation, pressure sensors measure the amount of fluid within a tank. If the pressure drops below a certain level, an alarm alerts the operator (sensors 11a, 11b and 11c).

Wireless and robust

A recent development within industrial and OEM manufacturing is the replacement of standard wired switches and sensors with wireless alternatives. On the crane illustrated, wired limit switches that used to measure the boom extension have been replaced by wireless switches using industrial 802.15.4 technology.

Wireless technology is especially effective for industrial situations where a wire might be subjected to repeated stretching and twisting, or contact with a wide range of hazardous materials and extreme environmental conditions. Wear and tear, and the subsequent downtime and expense is eliminated along with the wire.

Another important development is the improved robustness of the sensor technology itself, as well as the development of customized packaging options. Sensors and switches need to be designed to function well in the harsh environments that cranes and other construction equipment are subjected to, which requires resistance to vibration and shock, water, extreme environmental conditions and hazardous chemicals.

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