Types of Snatch Block
Maintenance of Snatch Block
The pulley should be checked termly according to the condition of operation and working environment. The period should be one time for every 3months at least. If available, static loading experiment on the basis of 1.6 times of rated capacity is suggested.
When examining and repairing the pulley, the parts should be cleaned with gasoline and coated with lubricant and anti-rusty oil, then re-assembled.
In the handling process, the pulley is not allowed to throw and smash to avoid component deformation.
If you do not use the pulley for a long time, it should be cleaned and then coated with anti-rusty oil, stored in a ventilated, dry place to avoid corrosion.
Regulations of Safe Use the Snatch Block
Overload is prohibited, no stands under the lifting objects .
Confirming the pulley is intact prior to use, the lubrication of the transmission part is well and idling situation is normal.
The hook should be scrapped if one of the following cases appears
a) Crack
b) If worn, the actual height of the dangerous section is less than 95% of the basic dimensions
c) Deformation of hook mouth is more than 10% of former size
d) Torsional deformation is more than 10%
e) Dangerous section or hook neck generates plastic deformation
a) crack
b) radial wear of wheel groove reaches 25% of the nominal diameter of the wire rope
c) the wear of the groove reaches 10% of basic dimensions.
d) Unequal wear of the groove reaches 3mm
e) other defects
The total load of the pulley should not exceed its rated capacity. When only part of wheels is used for lifting for the multiple sheave blocks, the loading capacity should be lowered and the reduced data is determined by numbers of ratio wheel. The gravity centre of the object should also through the centre line of the pulleys.
When the pulley is used under the rated capacity, movement speed of the wire rope shall not exceed 30 m/min. If the impact load is comparatively bigger during the lifting, upper grade pulleys should be adopted, otherwise accident may occur.
When use the pulleys lift the high temperature or corrosive medium, if there is thermal radiation or contact with corrosive medium, upper grade pulleys should be adopted
If the wear of the middle diameter of the centre shaft reaches 2% of basic dimensions, the pulley should be scrapped.
The pulleys should be scrapped when the wear of sliding bearing thickness reaches 20% of basic dimensions defects on the ball bearing.