Store portalkraner er det mest almindelige løfte- og håndteringsudstyr, der anvendes i industri og byggeri. De bruges ofte til tunge løft og flytteopgaver i industrielle miljøer såsom havne, byggepladser og produktionsfaciliteter. Portalkraner er udstyret med en løftemekanisme, der kan løfte og sænke tunge genstande. Mekanismen omfatter normalt et kran- eller spilsystem, som kan være elektrisk, hydraulisk eller drevet af andre midler, afhængigt af krandesignet. Det er kendetegnet ved sin høje, stive stålkonstruktion, der spænder over et område, understøttet af ben eller søjler på begge sider.

Gantry cranes are widely used in various industries of the national economy such as metallurgy, electric power, ports, logistics, machinery manufacturing and marine engineering. They are important process equipment for industrial production and are related to the safety of people's lives and the safety of national economic operations. and social stability are important components of public security in all countries. The development momentum of my country's hoisting machinery industry is strong. As of the end of 2017, the number of hoisting machinery in my country reached 2.2375 million units. According to the "Notice of the State Administration for Market Regulation on the Safety Status of National Special Equipment in 2017", the accident rate and fatality rate of cranes in my country rank first among the eight categories of special equipment. Therefore, there is an urgent need for an effective means to ensure the safety of in-service cranes. Safe and reliable operation of machinery.