Anti-Two Block Crane Safety Solution

Anti-Two Block System – Safety Always Comes First!

At some point of time, all of us involved in the heavy construction activities have seen workers being carried in their man-baskets using the hook of a crane. The whole process surely does look dangerous but is that in reality the case? The answer would be a yes. Construction workers sometimes put themselves in great danger while getting their tasks done, even if it means being lifted in a crane to great heights to reach and come back to/from their working points. Though we don’t condone this man lifting, it is a reality of construction work and as such requires a great deal of safety forethought and equipment.

The anti-two block system

One device which aids the safety of the workers being carried in the man baskets (as illustrated above) is an anti-two block system or A2B system for cranes. To know what an “anti-two block system” is, you must first know what a two block is.

What’s two-block?

Two-Block is described as the very dangerous occurrence during which the lower load block (or hook assembly) comes in contact with the upper load block (or boom point sheave assembly), interfering with safe operation of the crane to a great degree. When this occurs, life-endangering forces are applied on the hook which carries the workmen, creating a strong probability of them (the load in the man-basket) falling off thereby putting the life of the men and the safety of the surroundings in a great deal of danger.

How it works?

The A2B System is an electrical device which has a built in sensor. It facilitates the task of preventing the hook from coming in contact and colliding with the sheave. This effectively mitigates the chances of the workers or load crashing to the ground.

The technicality behind this can be explained in simple words. The anti two-blocking device comprises of a weighted ring round the hook line; this ring is suspended on a chain which can be traced to a limit switch which is attached at the boom tip. When the hook assembly comes in contact with this above mentioned suspended weighted ring, the switch opens and triggers an alarm in the cab. This warns the man operating the crane to stop hoisting further to mitigate any danger to the lives of the people involved. Some switches also activate a lockout solenoid that automatically prevents further hoisting.

Check if your crane has the device installed!

All the modern cranes incorporate the compatibility of an anti-two block system. As a matter of fact, if your crane does not, it is highly unsafe and may well be prohibited by the project/infrastructure/construction rules of the site. Furthermore your insurance may be negated if you have an accident without one installed.

The varied uses

The benefits of this A2B system to a crane are numerous. Apart from increasing the safety of your crew, it also makes sure that when you lift extremely heavy loads up to heights which test the maximum capability of your crane, the load does not fall off due to rope breakage.

Modern anti-two block systems come as wireless devices with great battery lives. However, apart from having an anti-two block system in place, you must also ensure that the ground-level operators and the crane-operator keep their eyes open to any encumbrances that might occur on site.Choose what’s right! For more information take a look at some good Anti-Two Block systems on the LSI Wireless site. These are excellent, fully certified anti-two block switches and anti-two block displays which are fully wireless. You can order them with ease and it will ship within days!