M 6076 M
rev 8 – 06.2021
Page 13/40
GB
DESCRIPTION AND APPLICATIONS OF THE EQUIPMENT
Simple yoke pulley is a return pulley dedicated to slow applications.
DD range is used with rope, ES range is used with wire-rope.
A simple yoke pulley permits
lifting or deviation
- without limit on use height or
distance (limit only depends on length of the rope/wire-rope).
The cast iron sheave is rotation free.
Suspension of the pulley is fitted with a swivel hook with safety latch.
Important height of bearing flanges permits easy installation of the rope
or wire-rope, and ensures space for splice.
It is important to control if anchoring point of the pulley is safe and warrants the
pulley cannot slip out of its hanging point (translation stop).
Mechanical resistance of anchorage point of the pulley must at least correspond
to WLL of the pulley.
Calculation of loading of a snatch blocks
The maximum Working Load Limit (WLL) written on the side of the block is the maximum load that should
be exerted on the block and its connecting fitting.
This total load value F varies with the angle (
α
) between the incoming and departing lines to the block.
The following table indicates the factor to be multiplied by the line pull to obtain the total load F on the
block.
Angle
α
Effort applied on suspension « F »
0°
WLL winch x 2
15°
WLL winch x 1,98
30°
WLL winch x 1,95
45°
WLL winch x 1,85
60°
WLL winch x 1,73
90°
WLL winch x 1,41
120°
WLL winch x 1
150°
WLL winch x 0,52
180°
WLL winch x 0
Always ensure :
F < pulley WLL
F < anchoring point resistance.
Cast
iron
sheave
Bearing
flange
Safety latch
Hooking
suspension
