The complete component of the hoist
The crane block or hook block is considered the complete component of the hoist and it’s linked to the crane by the rope pulleys/sheaves through the rope.
Its design depends on the crane's purpose and concept design whereas rope pulleys or sheaves and hook assembly design will be the key factor to achieving customer requirements and expectations. Sheaves must keep a proportional relation and must be symmetric to the gravity centre of the Crane Block.
Last decades sheaves diameter has decreased thanks to wire ropes advanced technology using more flexible wire ropes, reducing rope diameter and increasing strength thanks to very advanced materials, having decreased the historical factor (rope diameter (d1) x factor=sheave diameter (D).
The number of sheaves in the Hook Block will depend on the total WLL of the Hook Block and individual sheave WLL: falls are called to the twisted rope, whereas 1 sheave has always 2 falls and 2 sheaves have 4 falls.
The fall must have a certain angle for safety reasons: regularly the maximum angle is regulated by International Standards.
Modern hook block designs need to respond to the latest customer demands:
- Easy to disassemble to exchange hook type and replace inner components and accessories such as bearings and sheaves.
- Easy to grease it during maintenance, in order to keep all turning parts lubricated.
Proof Test Load (PTL) is being performed at Irizar Forge benches in order to cover a full guarantee to the crane operator.
A complete maintenance manual is being delivered to the customer full of recommendations and good practices from the original manufacturer for a safe and long-lifetime component.