移动式起重机吊装作业的安全管理.ppt

* * * * * * * * * * * * * * * * * * * * * 7 * * * * * * * * * * * * * * * * * * * * * * * Fiber cores are ropes made from fibers formed into yarns, then into strands and finally into the finished core form. There are two general types of fiber: natural vegetable material, such as sisal, manila and cotton and synthetic filaments, such as polypropylene or polyethylene. Steel cores may be an independent wire rope (IWRC) or, in the case of small diameter ropes and some rotation-resistant ropes, a wire strand core (WSC). These steel cores provide more support than fiber cores to the outer strands during the rope’s operating life. Steel cores resist crushing, are more resistant to heat, reduce the amount of stretch, and increase the strength of the rope. * Have the class members provide their thoughts of suitable allowances Write the student ‘guess’ on the board for future discussion Do not provide comment at this stage * Disadvantage of Fiber core rope is that it is not suitable for being wound onto a winch drum. The pressure created by the outer wraps will crush the fiber core of the underlying wraps. * The reason for left hand or right hand lay is to accommodate the different winch designs from various manufacturers. The end of the winch to which the rope is anchored and the direction of winch loading each effect the decision of which lay is the correct lay. The incorrect lay will result in rapid wear of the rope, increased number of broken wires and difficulty in maintaining an orderly laying of the rope onto the winch drum. Has any class member ever experienced problems with a FSWR when trying to wind it onto a winch drum? The most probable cause is that it was the wrong direction lay for the winch! * Fiber cores are ropes made from fibers formed into yarns, then into strands and finally into the finished core form. There are two general types of fiber: natural vegetable material, such as sisal, manila and cotton and synthetic filaments, such as polypropylen