Crane bridge crane "roll over" accident prevention

China's steel  bridge crane  is the most important metallurgical and other large enterprises, the most commonly used lifting, transportation and many other important equipment operation. Bridge crane known as "crane." Bridge crane "over volume" accident also called "hook heaven", belonging to one of the  overhead bridge crane  fatalities. The time of the accident, the light fixed pulley group squeeze bad, damaged wire rope scrap; severe group and the hook hanging objects fall to the ground, the consequences could be disastrous. Crane accidents nationwide class "over means" accident also accounted for a large proportion of the resulting economic losses and even very serious casualties. Therefore, the need for prevention and control of serious governance.


"Roll over" Accident Cause Analysis

People generally believe that as long as the bridge crane limit switch so that it will not happen "roll over" accident, this is a wrong understanding. Even if the limit switch itself, under normal circumstances, there are still many reasons that can cause "sky hook", such as: mechanical reasons - the brake is not enough tight, the limit caused by vertical swinging foot "over volume"; electrical Cause - Operation short circuit, then
, The wiring is wrong, main contact adhesions, the controller unit is damaged or with the gap caused by the ultra-poor "over volume"; operational reasons - control handle positioning error, excessive running hook group tour swing caused by the "roll over" and so on.
Meanwhile, we can not superstitious so-called dual limit setting, because for their own reasons not limit switch triggered by the "roll over" accident, the more the limit switch will not help. Thus, the control "over volume" accident was a comprehensive work, we must overcome the simplicity of understanding and one-sidedness of the accident in order to achieve a more comprehensive and effective containment.
Poor working conditions, accident control some metallurgical companies, mining companies, machinery manufacturers, bridge crane operating environment is very harsh. As smoke from various smelting furnace has occurred, causing serious consequences, the driver can perceive. Zhuo Lu dark sprouts for the stack: the stem police stuffed potato sets of five generations of good curly curse fog Mino kiln Ming Su steamed in a manner embroidery # 17 # day vehicles designed and installed such devices. Specific control process, crane in operation, when the hook set up, once the carom limit horizontal ruler (regardless of what caused the "roll over", hooks groups are bound to the first strike against the corresponding horizontal ruler or the other within the normal limit switch indirect action closed off point link), in the limit horizontal ruler starts lift, causing the limit switch normally closed off at the same time, with linkage alarm device for closing the normally open points, electric horn sounded, the driver will inevitably detect, immediately take emergency control measures, you can avoid the "roll over" accidents. The car previously occurred almost every year "over volume" accident, since the installation of such a warning device, has been unharmed. Such other types of alarm limits appropriately improved control system, can be used, and in the non-concentrated smoke, loud noise crane working environment is also necessary to install an alarm device in order to achieve safety.
Note base loop can be hail fog ink flow relay din bottom to take the main circuit power supply, also by lighting, bells take power with isolation transformer. Small power electric horn Wen Qian installed in Benedict driving indoors, can be prepared by suspension cables or power supply cables motorcycle spare rope two. Limit switch with L × 10 a trip to open a total of five types, which are still connected to the limit normally closed loop. Normally open alarm circuit connection.
Fast speed. High frequencies. Working conditions, long travel accidents to control some of the main bridge crane cut tired running faster, fork frequent starts and lifting height often close to or reach the limit height, in the case of the work of the crane, must require limiting devices that are able to both sensitive and accurate positioning by bite. Now for the bridge crane divination LX7-1 type limit switch is gifted Ding _ very common foot type "i Burgundy and touch-type rope swing rod limit device, because it destroyed the question is simple gears to avoid Man of the foot horn seal installed in small power Benedict driving indoors, can be prepared by suspension cables or power supply cables motorcycle spare rope two. Limit switch with L × 10 a trip to open a total of five types, which are still connected to the limit normally closed loop. Normally open alarm circuit connection.
Fast speed. High frequencies. Working conditions, long travel accidents to control some of the main bridge crane cut tired running faster, fork frequent starts and lifting height often close to or reach the limit height, in the case of the work of the crane, must require limiting devices that are able to both sensitive and accurate positioning by bite. Now for the bridge crane divination LX7-1 type limit switch is gifted Ding _ very common foot type "i Burgundy and touch-type rope swing rod limit device, because it destroyed the question is simple gears to avoid they rely on accurate positioning of the feet. Now for the overhead crane LX7-1-type line
Cheng foot switch is superior to the ordinary limits and rope-style touch-type swing rod limit device, simply because it hides between the gears to avoid foot-in limits and limits of the swing lever means some shortcomings, however, the switches for such work under inadequate conditions, which can not permanently accurate positioning, prone to sudden failure caused by "over surmise" accident. This is due to its modular positioning means is the slice, the adjustment of positioning is maintained by the spring pressure, the recovery position. However, relying on a small spring pressure, in this fast speed, often touching the condition is impossible to maintain long-term change. So, how to resolve this contradiction  After analysis research, the positioning of the switch can be combined from the original link to the overall style, we can guarantee the long-term in any case, accurate positioning. Attendant can not adjust the positioning problems brought by unscrewing three foot screws, rotate the switch to an angle, so that the passive and active wheel wheel disengagement, and then reset the rugged adjust positioning methods to solve (this switch size is not large as 16cm × 9crn × 18CITJ, easy to operate. This approach works well by practice.
General operating conditions accident prevention
We must first adjust the brake to maintain proper tightness, or by Ding brake is too loose can cause pity because inertia caused by running "over volume" accident. Always test the limit switch is sensitive and reliable, to prevent adhesions points, axes moving disorders and other causes of extreme control failure. On the small-type stroke using Lxl0-31 rape-related foot stroke limit device, to switch the bottom end of the swing arm welded non-weight top column, preventing the use of too long, because the positioning angle plate to the top of the pit bottom switch switch failure caused . When the disc prohibits protection against noise contactor armature pull extraordinary general contactor or circuit failure can not suck Park station, on top of the contactor armature forced to continue working, because forcibly held top BU Vice-limit control can cause failure.
Double limit a worm type, foot type configuration, the positioning of the worm or lower limit Ding foot-in limit position about 20cm, so can the vice segmented control, fork right foot-in limit play a protective role. So too lao protection more complete.
Regularly monitored by the limit operation circuit is normal. Line group to prevent a short circuit, grounding made garrison limit failure, to prevent incorrect wiring caused by "over volume." Good earth loop maintenance, prevent soil adhesion contacts, contacts armature catching limits resulting failure.
Vice dig remind users to use KTJl5 series controllers. In the use of credits to be torn down zero meter positioning locking device. Or they may lead to "roll over."
Educating drivers handle the operation of the controller should have a positive, driving hook group to stabilize, to prevent misuse or illegal operations led to the "hook Heaven" incidents.