10.5.4 Slewing Facility

The jib arm may be slewed by manual pushing of the load, operation of manual gear or by power operation. Selection will largely depend on the magnitude and nature of the load or nature of the task to be performed.

Small, light loads may be easily slewed by hand, but the following should be borne in mind. Pushing on the load will cause it to swing away from the vertical centre line of the jib. The greater the distance between the load and the jib arm, the more accentuated the swing will become. When the jib arm then moves it will be delayed and then tend to snatch, causing the load to swing back and forth. This could endanger the operative and place excessive loading on the structure.

Ground level obstructions, e.g. machinery, may obstruct the path of the operative when pushing a load or the load may be suspended over a pit, teagle opening or similar. In such cases, a tag line may be fitted to the end of the jib arm to enable the operative to slew the jib.

The size, shape and weight of the load may be such that it is not possible for the operative to slew the jib safely by hand. Similarly, the load may be of a hazardous nature. In such cases, manual geared or power slewing should be considered, these also having the advantage of assisting the operative to position the load accurately.

The location of the slewing jib crane must be given careful consideration taking into account any potential hazards there may be such as the proximity of overhead power systems, nearby structures, machinery and other cranes. These may necessitate restricting the slewing motion of the jib arm to prevent it colliding with them. This may be done by the use of slewing stops.