A tower crane
must have automatic travel limit switches and automatic overload prevention devices that prevent overloading at any trolley position, the load block from travelling
beyond the highest allowable position specified by the manufacturer and the trolley from travelling
beyond the allowable limit specified by the manufacturer. limit devices on a tower crane must be tested before the crane is first used on each work shift
Any malfunction of an automatic limit or safety device on a tower crane must be remedied before the crane is used. If it is not practicable, due to the configuration of the workplace, to position sufficient test weights to test the maximum load limit switch before the crane is first used on each work shift, the maximum load limit switch must be set to activate at a load of less than 80% of the maximum rated capacity for the crane and tested using test blocks, and be reset to the maximum load limit for the crane and tested using test blocks before making any lift that is greater than the load limit setting established under paragraph .
A tower crane with a luffing boom must have an automatic limit device that prevents the boom being raised beyond the maximum permitted boom angle. "Luffing boom" means a boom that is raised and lowered about a pivot point to change the load radius.
Test blocks for testing overload prevention devices on a tower crane must be available at the tower crane site. The weights of test blocks required by subsection must be as specified by the crane manufacturer if the crane is erected in accordance with the manufacturer’s instructions, or a professional engineer if the crane has been erected other than in accordance with the manufacturer’s instructions. The weight of each test block required by subsection must be accurately determined and durably and legibly marked on that block. Test blocks, including the lifting point, must be designed by the crane manufacturer or a professional engineer.
UNIQUE brand Tower crane basic configuration was include limit device,welcome to visit us.