كتل السلسلة, تُعرف أيضًا باسم كتل البكرة المتسلسلة, 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?
A 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, قوى التأثير, wear and other unforeseen stresses.
تتراوح عوامل السلامة النموذجية للكتل المتسلسلة من 3 إلى 5. This means the block has 3 إلى 5 أضعاف السعة المقدرة لها في ظل الاستخدام العادي. تتطلب الهيئات التنظيمية مثل OSHA الحد الأدنى من عامل الأمان 5 for most general purpose lifting equipment. ومع ذلك, specialized chain blocks can have lower safety factors depending on the application, مثل كتلة بكرة السلسلة 20 طن.
حد حمل العمل (ذ.م.م)
حد حمل العمل (ذ.م.م) 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. عادةً ما يتم تصنيف كتل السلسلة بـ WLL محدد أقل بكثير من قوة الكسر النهائية.
Under normal usage, the sum of all loads acting on a chain block should not exceed its stated WLL. يؤدي التحميل الزائد على كتل السلسلة إلى زيادة خطر فشل المكونات وإطلاق الحمل العرضي. قم دائمًا بالرجوع إلى علامة WLL أو لوحة البيانات عند اختيار كتلة السلسلة ذات الحجم المناسب لمهمة رفع معينة.
Factors That Impact Safety
هناك عدة عوامل تؤثر على عامل الأمان و WLL لكتل السلسلة:
- Pulley Size & Number – More/larger pulleys provide higher mechanical advantage but lower load capacity.
- درجة السلسلة – Higher grade chain with greater breaking strength allows for higher WLLs.
- جودة المكونات – Better material and construction techniques increase rated capacities.
- الشهادات – Certified chain blocks by reputable standards organizations provide a defined WLL.
- تطبيق – 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 إلى 5 times are common for general purpose chain blocks, providing a buffer for unforeseen loads and stresses.