附录AHoist crane metal structureFlows -like in the hoist crane, the majority of tire hoist crane, the crawler crane as well as the partial autohoist and special-purpose flows -like the hoist crane, all installs has clothes rack the bracket arm, and through lifts using its peak block and tackle installs changes lifts the steel wire position, thus realization heavy item fluctuation; Again changes its height of lift and the working radius through the change clothes rack bracket arm length and the angle of tilt. Therefore, maintenance clothes rack bracket arm incompleteness is extremely important. Because the hoist crane rises and falls the heavy item work content the multiplicity and all kinds of work environment, as well as the hoist crane pilot operational level high low status reason (has also contrary operation), these can create clothes rack the bracket arm varying degree damage, even folds the arm or the personnel casualtyOn clothes rack the bracket arm steel pipe is specially in the welding place, very easy to appear the crack; This must examine carefully, when necessity applies the magnifying glass careful observation. According to we many year experiences, is very small when the crater place crack, must carry on the regular track inspection, gazes at the crack closely the development change, in order to take the measure promptly. When crack width as big as 1mm above, should the prompt patching. The concrete method is, carries on first to the crack place original crater polishes, removes how many to regard the special details to decide; Then carries on the patching; Finally renovates well then.When the pit depth achieved the steel pipe the arm thick size, also the pit distortion diameter achieves when 25mm (diameter for 25mm) and a straightedge, if the pit position in clothes rack on the bracket arm steel pipe surface, then defers to the method which shown in Figure 1 to determine the pit the depth, soon chooses the good steel ball to put in the pit, if the steel ball apex up just could with right angle under along the contact, we be possible to regard the steel ball by now the diameter for the pit depth. If the pit position in the steel pipe side or under, after may use the butter to stick to first the steel ball carries on again the survey. To this kind of maintenance damage, the available general material quality and the original steel pipe same steel pipe welding reinforcement, namely takes section of steel pipes to divide into along the middle line two half, builds its nose the incline, has exempted the crater to be vertical to clothes rack the bracket arm steel pipe length direction. Must treat in front of welding the original clothes rack bracket arm steel pipe above welds place paints polishes cleanly front, prepares for welds When clothes rack the bracket arm simple root steel pipe surface damage quite is serious, should adopt its damage serious section of steel pipes removes, welds section of steel pipes the method to carry on processing, but must add on a section inside the steel pipe to strengthen the steel pipe. Front in order to cause to weld strengthens the steel pipe to be able the smooth insertion to remove in a section of clothes rack bracket arm steel pipe, strengthens the steel pipe to be supposed to make the similarly long two sections, and uses the thread successively and welds two ways to carry on the connection. Strengthens steel pipe L1 and L2s length must a section of short 20mm which removes compared to clothes rack the bracket arm steel pipe, also its outer diameter should compared to clothes rack bracket arm steel pipe inside diameter small 2040 m, cause to strengthen the steel pipe both to be possible to move in clothes rack the bracket arm steel pipe and no longer becomes less crowded. Will strengthen steel pipe L1 and L2 first inserts clothes rack in separately the bracket arm steel pipe, and will use them the screw joint not to be able to get up, then will screw tight causes two shoulders to depend on strictly, will hold looks strengthens the steel pipe after the position, after will occupy separately its screwtop the position, separately and two will weld its screwtop place the jail already to be possible. Clothes rack the bracket arm steel pipe crater must make the incline, when the steel pipe spool thread perpendicular line included angle for 1030 between, like the damage is the multi-root steel pipe, should choose 10. Here, again earnestly surveys clothes rack the bracket arm steel tube welding good after actual gap size, and refers to the shape which shown in Figure 2, the next section of steel tubing material, the both sides make 30 inclines, cuts open the welding along among in clothes rack in the bracket arm steel pipe gap; Finishing touch, paints then This time, 4 steel pipes all must weld, therefore should defer to Figure 4 requests the vehicle to make 4 inside diameters to strengthen the tube, after the inside diameter strengthens wall