Veliki portalni žerjavi so najpogostejša dvižna in manipulativna oprema, ki se uporablja v industriji in gradbeništvu. Pogosto se uporabljajo za dvigovanje težkih in premikanje v industrijskih okoljih, kot so pristanišča, gradbišča in proizvodni obrati. Portalni žerjavi so opremljeni z dvižnim mehanizmom, ki lahko dviguje in spušča težke predmete. Mehanizem običajno vključuje sistem žerjava ali vitla, ki je lahko električni, hidravlični ali drugače gnan, odvisno od zasnove žerjava. Zanj je značilna visoka, toga jeklena konstrukcija, ki se razteza čez območje in je na obeh straneh podprta z nogami ali stebri.

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.