Blocchi a catena, noto anche come paranco a catena, are a type of lifting device that uses a chain to raise and lower loads. They provide mechanical advantage through a system of pulleys. When selecting and using chain blocks, it is important to consider the working load limits and safety factors to ensure safe and efficient lifting.
What Is A Safety Factor?
UN chain hoist safety factor is the ratio of breaking strength to working load limit. It indicates the block’s maximum load capacity relative to its forces under normal operation. Safety factors are incorporated into chain block design to account for dynamic loads, forze d'impatto, wear and other unforeseen stresses.
I fattori di sicurezza tipici per i paranchi a catena vanno da 3 A 5. This means the block has 3 A 5 volte la capacità nominale per l'uso normale. Gli organismi di regolamentazione come l'OSHA richiedono un fattore di sicurezza minimo di 5 for most general purpose lifting equipment. Tuttavia, specialized chain blocks can have lower safety factors depending on the application, ad esempio paranco della puleggia della catena 20 tonnellata.
Chain Working Load Limit (WLL)
Il limite del carico di lavoro (WLL) refers to the maximum load a chain block is as designed to safely lift under normal operation. The WLL takes into account the safety factor incorporated into the block’s design and components. I blocchi di catena sono generalmente classificati con un WLL specifico che è significativamente inferiore alla loro resistenza alla rottura massima.
Under normal usage, the sum of all loads acting on a chain block should not exceed its stated WLL. Il sovraccarico dei blocchi della catena aumenta il rischio di guasto dei componenti e rilascio accidentale del carico. Fare sempre riferimento al marchio WLL o alla targhetta dati quando si seleziona il paranco a catena della dimensione appropriata per una determinata attività di sollevamento.
Factors That Impact Safety
Come professionista produttori di paranchi, we are very responsible to tell you that there are several factors that affect the safety factor and WLL of the chain block:
- Pulley Size & Number – More/larger pulleys provide higher mechanical advantage but lower load capacity.
- Grado della catena – Higher grade chain with greater breaking strength allows for higher WLLs.
- Qualità dei componenti – Better material and construction techniques increase rated capacities.
- Certificazioni – Certified chain blocks by reputable standards organizations provide a defined WLL.
- Applicazione – Specialized blocks for severe service have lower safety factors for cost efficiency.
Overview For The Safety Factors Of Chain Blocks
The safety factor and working load limit of chain blocks indicate their rated lifting capacity relative to their actual breaking strength. Safety factors of 3 A 5 times are common for general purpose chain blocks, providing a buffer for unforeseen loads and stresses.