(b)No jib crane having either a fixed or a derricking jib shall be used after one year of the coming into effect of this Rule unless it is fitted with an accurate automatic indicator which-(i)indicates clearly to the driver or person operating the crane when the load being carried or lifted approaches the safe working load of the crane for the radius of the jib at which the load is being carried or lifted; and(ii)gives an efficient sound signal when the load being carried or lifted is in excess of the safe working load of the crane at that radius: