Hoist equipment in the peri-China economic sectors have a wide range of applications in modern production occupies an important position, is essential to the process of modernization of production aids. hoist equipment in orbit, due to manufacturing or installation error, equipment failure in use or wear, may the emergence of different levels of car "three legs" phenomenon, easily lead to equipment failure, lower productivity, causing safety problems. Based on the three-legged crane runtime phenomena cause analysis, to find solutions crane, "three-legged" an effective way to prevent lifting Machine because "three-legged" as a result of accidents, and ensure the safety of life equipment and high-ranking officials.
1， lift hoist , "three-legged" phenomenon
Crane "three-legged" phenomenon multi-finger bridge crane trolley anomalies occur, crane trolley stop often four o'clock the ground, but if the entire structure of the crane very rigid manufacturing precision low (especially for lifting trolley or a small span Crane purpose machine), it may
Will result in only three wheels with the ground, and a wheel floating phenomenon, a phenomenon known crane, "three-legged" phenomenon
hoist and trolley "three legs" phenomenon resulting security risks
Car to a "three-legged" phenomenon, resulting in four wheels only three wheels in contact with the track running, this will be the operational performance of the crane have some impact. If the wheel is vacant, even the safe use of cranes will produce great harm.
1) Start the car and braking causing twisting body shake, shake the whole crane, running instability, there are security risks;
2) a floating wheel, trolley wheel loads by only three could cause maximum wheel load exceeds the design value. Crane normal circumstances, the wheel material is generally used steel ZG310-570 above, after the heat treatment of deep wheel tread surface hardness of HB300-380
You can use a decade or more. Wheel pressure exceeds its design value causes the wheels badly worn or broken due to the instability of the wheels and the wheels need to be changed frequently, affecting the normal production and operation of enterprises;
3) causing gnawing rail car, damaged car track, increasing the running resistance, wheel wear serious, could easily lead car derailment;
4) If the car for a long time in the "three-legged'' phenomenon run, could easily lead to deformation of the bridge due to uneven force, reduce the service life.
3 car "three-legged" phenomenon Cause Analysis
Causing car "three-legged" phenomenon are: trolley and trolley tracks own fault, deformation, installation does not meet the requirements or wear. Common situation now is as follows:
1) the car frame shape defects or deformation due to a fault, resulting in four wheel tread is not on the same plane.
2) trolley wheel configuration, because the chosen wheel diameter is inconsistent, or tread wheel material hardness and heat treatment is not enough, wheel tread hardness as a result of inconsistent use of wheel wear inconsistent.
3) installation not in the same plane or axis of the wheel taper direction installation error, which is likely to cause a wheel vacant; certain wheel assembly, in order to achieve self-adjusting at both ends runtime synchronization wheels, wheel tread often active in the system at 1:1 0 taper; installation Must pay attention to two opposite wheels taper and cone outwards, if the direction of the tapered tread and wheel installed anti, not only can not achieve the role of self-adjustment, it will cause a wheel unconnected.
4) Since the parallelism and flatness rail, rail and rail joints bending levels caused by excessive height difference between two wheels on the same side of the
lift hoist are, respectively, at a certain track is not in contact with the track; rail mounting plate is not compacted, not keep track of bearer level bearer rail
Road subsidence causes a wheel vacant, for those who often run at full capacity cranes, this phenomenon is more common.
4 "three-legged" phenomenon inspection
1) checking the wheel trolley: clothes when the wheel diameter tolerances and deviations wheel inspection; in wheel size measured using a crane, wheel wear test are consistent.
2) check the track: track elevation measurement deviation is within the allowable range.
3) car "three-legged'' comprehensive examination: car" three-legged'' Sometimes the combined effects of a variety of reasons, both wheels reasons, but also because the track. Detection, open car brakes, vigorously promote the trolley travel, in orbit segmentation analysis. If the car The whole stroke is always a floating wheel, the wheel diameter and the tolerance specification, the axis of the wheel is judged not in the same plane; if only the local area a "three-legged 'phenomenon, shown in Figure 2, the wheel A is a gap appears at chu, plugs with a feeler or obtain data sheet To promote the car into the big wheel makes a point C, there is a gap, indicating the track at a low; A wheel at a point there is a gap, C wheel into a point of no gap, then it is determined that the wheel diameter deviation caused.
trolley "three-legged" phenomenon measures for improvement
Run for the crane trolley wheel occurred during the "three-legged" phenomenon, according to the site inspection and testing, analysis of its causes, propose practical measures for improvement were:
1) Since four trolley wheels ranging in diameter caused by the "three-legged" phenomenon, replace the wheel. If diagonal two wheel diameter is too big or too small to cause a wheel vacant, should also replace the two wheels on the diagonal. Active diameter of the wheel should be consistent, to avoid
While for the new drive wheel and the other side of the old active case of a wheel; tread surface has worn, and to wear different tread surface the diameter of a set of wheels in a lathe into the same diameter and the specified tolerance range, and then re-heat treatment step.
2) Since the car body deformation and a "three-legged'' phenomenon, should be corrected body until four wheel axis in the same plane. If it is due to improper installation of the" three-legged'' phenomenon, installation should be adjusted errors. Car repair deformed, generally a more simple
Single shimming method. First, determine which wheels suspended in a relatively flat track wheels and rails measured gap, loosen the screws fixing the bearing housing on the key inserted in the horizontal gap as thick gasket and then tighten the nut; course, if the car seriously deformed , it must
Shaping up for the car. Under normal circumstances in order to adjust the driven wheel as well, if adjustments need to take the initiative to check and adjust the rear wheel trolley drive system.
3) As the track rugged, depression lead to "three-legged'' phenomenon, we should begin to eliminate depressions track for track exist smaller local depression, can be added to adjust the track pad, use an ordinary steel, its thickness measured error according to the election fixed, plate requirements smooth surface, No punch, the track may not have floating phenomenon, with belt bolts fixed to the lower plate and beam. For the track there is a serious depression and under the main beam deflection, deformation of the "three-legged crane'' phenomenon should be used flame straightening, correcting or application prestressed prestressed tension, etc.
Ways to repair the main beam, a fundamental solution to the problem of rail dent.