Electric Level Luffing Grab Duty Crane
This crane is generally mounted on Rail tracks. This crane is of fixed jib type. This machine is fitted with Close & Hold winches (Hoists). These machines are used in the Ports for handling ship cargo and having Grab bucket. Sometime Hook is also attached for lifting application.
The lifting capacities for such machines are usually radius based for Main Grab duties and usually remains the same throughout Maximum to Minimum boom radii. These cranes sometime have Goose Neck type boom.
The Indicators suitable for ELL Grab Duty crane for Wylie’s range are KY2001/FORTIUS, Safe Load Indicator / Load Moment Indicator / Total Load Moment Indicator System. The load sensing is done by Line Riders / Load Links / Load Pin.
HOW THE SLI SYSTEM WORKS ON A GRAB CRANE
The Wylie Crane Safe Load Indicator System is suited to meet the requirement of the ELL Grab/Hook Cranes. The Grab Cranes usually have two hoists viz Hold Hoist, Close Hoist. The SLI system for this machine has two separate load sensors (Dynamometer) for the individual hoist. The reason behind this scheme of load sensing is requirement of only Close Hoist, during the grabbing operation. This leads to unequal load sharing of the two hoists. During this process the hold hoist is almost tension free. When the grabbing is over the Hold Hoist comes to play. When the operator starts lifting the load, both hoist come under load. Thus SLI system for Grab cranes monitors load in both close and hold hoists. The transducers from both the Hold and Close hoists load sensors send signal to the controller. In the controller signals are summed together and utilized for display, comparison purposes to generate audio/visual alarms.