Jib crane bracket fails8 December 2004
The US Navy has issued a crane safety advisory for components of Gorbel wall-mounted jib cranes following a Navy load test incident in which a connection plate buckled on a Gorbel series WB100 and the crane boom lowered until a test load reached the floor. According to the Navy, the crane consists of a wall bracket, a rotating boom connection and a hinge pin. Two small plates are welded to the bracket to act as boom rotation stops. According to the Navy investigation, the rotating connection contacted the bracket. “Excessive contact of boom connection plate with the rotation stops can cause deformation in the connection plate resulting in reduced buckling strength. Deformation or damage to the boom connection plate may be undetectable by normal operator daily checks,” the Navy said. It also said that Gorbel is revising the installation and maintenance manuals for proper installation and use of the rotation stops. Gorbel sales and marketing VP David Butwid, however, told Hoist he had no knowledge of the report. In the meantime, the Navy is recommending its crane users inspect the wall brackets for damage, and if any is found or suspected the crane should be taken out of service. It also advises users to remove rotation stops that are hitting rotating boom connections, or to install additional ones along the boom or the wall so that the rotating boom does not hit the wall bracket.