Crane normal operation, the wheel rim and the orbit must maintain a certain gap between the design maximum gap of 30-40mm, but in exceptional circumstances, the wheel is not in the middle of running its tread,hoist gantry crane rim and squeezing each side of the track friction gnawing rail failure occurred, affecting the safe operation of the crane.
First, the dangers of eating track
1. Reducing the service life of the wheel and rail. Intermediate bridge crane in the type of work under normal use, the wheels can be used for 10 years or longer, but the gnawing serious rail bridge crane, wheel life difficult than one year, or even only a few months, resulting in frequent replacement wheels. Side of the track rail friction also reduces the service life, serious, track access is only 3-5 years scrapped.
2. Increase the running resistance. According to the determination, serious gnawing rail
bridge gantry crane running resistance is the resistance of 1.5-3.5 times normal operation, causing the motor and drive mechanism to increase the load even overloaded, the motor can be severe burning or transmission failure. Bridge crane with the risk of derailment. Overhead crane rails serious bite, the wheel rim is compressional deformation, may climb the top of the track causing derailment.
3. Negative impact on the building structure. Easy to produce horizontal rail crane gnawing lateral force, causing lateral displacement of the track, the track bolts loose. In addition,sino hoist the lateral force transmitted to the plant through the roof rail, seriously affecting the bridge and plant stress conditions so trusses Itabashi partial loosening or breakage.
2013年8月20日星期二
Mobile crane are several?
Mobile crane is rotating jib crane. Since the power system on its own drive, also known as self-propelled cranes, which used to be called pneumatic tire assembly wheeled cranes. Mobile
overhead gantry crane can travel long distances and flexible conversion job site, mobility, and therefore widely used.
There are mobile crane truck crane, tire cranes and crawler cranes, their characteristics are briefly described below.
1. Used truck crane chassis, with a car driving through the performance, speed is high. Disadvantage is running can not load, lifting legs must fight. But because of its flexible, fast transfer characteristics, making the use of mobile cranes largest amount cranes.
2. Crane uses a specially designed tire tire chassis, wide track, good stability, can work around all sides, on flat ground without legs can load driving. In other countries, especially off-road tire tire hoist gantry crane more widely used, much to replace cranes trend.
3. Crawler crane with crawler chassis, walking by the crawler crane. Compared with the wheeled crane has its outstanding features: Crawler large contact area with the ground than live small, in the soft, muddy ground operations; traction coefficient is high, climbing degree, you can travel on bumpy field; crawler bearing wide, good stability, generally do not need to set outrigger devices. Weakness is cumbersome,bridge gantry crane slow driving on pavement damage effects, higher manufacturing costs.
There are mobile crane truck crane, tire cranes and crawler cranes, their characteristics are briefly described below.
1. Used truck crane chassis, with a car driving through the performance, speed is high. Disadvantage is running can not load, lifting legs must fight. But because of its flexible, fast transfer characteristics, making the use of mobile cranes largest amount cranes.
2. Crane uses a specially designed tire tire chassis, wide track, good stability, can work around all sides, on flat ground without legs can load driving. In other countries, especially off-road tire tire hoist gantry crane more widely used, much to replace cranes trend.
3. Crawler crane with crawler chassis, walking by the crawler crane. Compared with the wheeled crane has its outstanding features: Crawler large contact area with the ground than live small, in the soft, muddy ground operations; traction coefficient is high, climbing degree, you can travel on bumpy field; crawler bearing wide, good stability, generally do not need to set outrigger devices. Weakness is cumbersome,bridge gantry crane slow driving on pavement damage effects, higher manufacturing costs.
Overhead crane load sway reasons
When using material handling
sino hoist when the crane carts, trolleys and lifting mechanism motion by the respective operating instructions are usually controlled independently; when handling the material reaches the target position, due to the carts and trolley deceleration effects load swing phenomenon appears objectionable; when the load swing, the unloading operation can not be performed.
The above situation, only skilled operatives is possible by controlling the size of the car running to eliminate rocking. However, this requires highly skilled operatives operating skills and a high degree of concentration. Elimination of the load to adjust the load swing and microscopic target position takes a long operation time, which accounts for the handling about one third of the time required.
In addition, the overhead bridge crane load quickly run will cause much of a swing. Excessive load swing on-site operations pose a threat to personal safety. Also increases the load and the load swing around the possibility of damage to the goods being. Swinging has become a crane load limit movement of materials to improve the efficiency of a major factor.
Crane brake inspection
Brakes are important parts of the crane, the agencies directly affect the accuracy and reliability of the movement. Therefore, we must carefully check the hoist and luffing two institutions brake condition, observe the opening of the brake shoe friction elements and the wear of the brake pads. Band brake brake band to pay attention to check for cracks in steel backing, whether flexible transmission brake,hoist gantry crane brake frame is intact and the main spring and the auxiliary spring elastic compliance.
Bridge crane track to determine: the dimensions of the goods to be able to pass the legs flat steel frame. Along the mast to meet stability requirements crane track direction. Note that track B and span S proportional relationship, and generally track B = (1/4-1/6) S.
The above situation, only skilled operatives is possible by controlling the size of the car running to eliminate rocking. However, this requires highly skilled operatives operating skills and a high degree of concentration. Elimination of the load to adjust the load swing and microscopic target position takes a long operation time, which accounts for the handling about one third of the time required.
In addition, the overhead bridge crane load quickly run will cause much of a swing. Excessive load swing on-site operations pose a threat to personal safety. Also increases the load and the load swing around the possibility of damage to the goods being. Swinging has become a crane load limit movement of materials to improve the efficiency of a major factor.
Crane brake inspection
Brakes are important parts of the crane, the agencies directly affect the accuracy and reliability of the movement. Therefore, we must carefully check the hoist and luffing two institutions brake condition, observe the opening of the brake shoe friction elements and the wear of the brake pads. Band brake brake band to pay attention to check for cracks in steel backing, whether flexible transmission brake,hoist gantry crane brake frame is intact and the main spring and the auxiliary spring elastic compliance.
Bridge crane track to determine: the dimensions of the goods to be able to pass the legs flat steel frame. Along the mast to meet stability requirements crane track direction. Note that track B and span S proportional relationship, and generally track B = (1/4-1/6) S.
Several crane introduce rehabilitation programs
General
overhead gantry crane for its large carrying capacity, good stability and a series of advantages are widely used in various types of workshops, factories and warehouses. However, the lack of impact of headspace height of overhead cranes, double girder bridge crane particularly important reason to use one. The workshop or factory roof reconstruction is very difficult work; re-build the crane bearing rail beam is put too much, so by the traditional general-purpose
overhead bridge crane structural transformation, reduce machine height, is the most viable solution to this problem methods.
Crane design principles explicitly mentioned in the three basic conditions:
Cranes and mechanical parts metal structure should have sufficient strength, stiffness and resistance to buckling;
Machine must have the necessary stability against overturning;
Prime mover has to meet the requirements of the job performance power brakes provide the necessary braking torque.hoist gantry crane During crane structural transformation, they must meet three basic conditions. Traditional designs were analyzed and found the car above the rail height is the height of the main factors affecting the whole world.
Through its orbit for small frame transformation can reduce machine height. Small frame metal structure change this transformation program will be the biggest feature is the horizontal support surface placed in the car, under the car axle instead of the traditional design will be placed on the supporting surface on top of the car axle. Rack mounted in the car lifting mechanism and other components "hidden" in between the two main beams and shelves trolley car parts below the highest point of the axle.
General overhead crane technology is mature, highlight the advantages. But according to the traditional design of a large crane machine height, in some special occasions can not install and use. Through the transformation of the trolley bridge crane structure can reduce the overall height of the overhead crane applications enhance the breadth. Above describes several rehabilitation programs, and in the actual production in the applications.
Crane design principles explicitly mentioned in the three basic conditions:
Cranes and mechanical parts metal structure should have sufficient strength, stiffness and resistance to buckling;
Machine must have the necessary stability against overturning;
Prime mover has to meet the requirements of the job performance power brakes provide the necessary braking torque.hoist gantry crane During crane structural transformation, they must meet three basic conditions. Traditional designs were analyzed and found the car above the rail height is the height of the main factors affecting the whole world.
Through its orbit for small frame transformation can reduce machine height. Small frame metal structure change this transformation program will be the biggest feature is the horizontal support surface placed in the car, under the car axle instead of the traditional design will be placed on the supporting surface on top of the car axle. Rack mounted in the car lifting mechanism and other components "hidden" in between the two main beams and shelves trolley car parts below the highest point of the axle.
General overhead crane technology is mature, highlight the advantages. But according to the traditional design of a large crane machine height, in some special occasions can not install and use. Through the transformation of the trolley bridge crane structure can reduce the overall height of the overhead crane applications enhance the breadth. Above describes several rehabilitation programs, and in the actual production in the applications.
2013年8月19日星期一
Threaded connection bridge crane demolition methods and precautions
Removing the threaded connection. Threaded connection in the mechanical connection is the most widely, it has a simple, easy to adjust and multiple disassembly and assembly advantages.steel crane Its removal easier, but also often due to inadequate attention, improper selection tools, demolition method is not correct and cause damage. Bridge crane screwed General demolition method is:
First, recognize the thread rotation, use the right tools (wrench, screwdriver sizes match), forced to be uniform. Remove threaded connections generally should not use an extension, only by the force of the special threaded parts, the use of specialized forging wrench, allows the use of extensions. To reduce labor intensity and improve work efficiency, should be adopted motorized wrench. Use special wrench to remove the stud.overhead bridge crane Special circumstances Removing the threaded connections:
1 decapitated screw off the surface and below the body disassembly:
a. the screw drilled into polygonal hardened steel, then screw extruder;
b. decapitated end of the center in drilling, tapping reverse threaded screw screwed into reverse spin out;
c. the screw holes (diameter equivalent to minor diameter), with the same specifications tap tapping; drilling large diameter threaded equivalent, attack large a diameter thread.
2 decapitated screws exposed on the outer surface of the body part of the demolition:
a. at the head sawed off groove with a screwdriver screwed out;overhead gantry crane migraine processed in off the head or square head with a wrench;
b. increase in off the head or nut welded curved rod out;
c. screws thick, use a flat shovel circumferentially excised.
First, recognize the thread rotation, use the right tools (wrench, screwdriver sizes match), forced to be uniform. Remove threaded connections generally should not use an extension, only by the force of the special threaded parts, the use of specialized forging wrench, allows the use of extensions. To reduce labor intensity and improve work efficiency, should be adopted motorized wrench. Use special wrench to remove the stud.overhead bridge crane Special circumstances Removing the threaded connections:
1 decapitated screw off the surface and below the body disassembly:
a. the screw drilled into polygonal hardened steel, then screw extruder;
b. decapitated end of the center in drilling, tapping reverse threaded screw screwed into reverse spin out;
c. the screw holes (diameter equivalent to minor diameter), with the same specifications tap tapping; drilling large diameter threaded equivalent, attack large a diameter thread.
2 decapitated screws exposed on the outer surface of the body part of the demolition:
a. at the head sawed off groove with a screwdriver screwed out;overhead gantry crane migraine processed in off the head or square head with a wrench;
b. increase in off the head or nut welded curved rod out;
c. screws thick, use a flat shovel circumferentially excised.
Crane under what circumstances replace the gear should be scrapped
Check the overhead crane gear has the following defects, should be scrapped Replacement:
1 in the root of the hoisting mechanism of the first gear shaft wear more than 10% of the original thickness of the tooth,hoist gantry crane the rest of the shaft of the gear tooth wear more than the original thickness of the fox;
2 carts (car) the first shaft gear reducer operating agencies wear more than 15% of the original thickness of the tooth,steel crane the rest of the shaft of the gear tooth wear more than the original thickness;
3 open gear wear is greater than 30% of the original tooth thickness;
4 lifting red hot or molten metal, acid,bridge gantry crane explosives, flammable and toxic substances such as crane gear scrapped according to the above criteria accordingly halved;
5 due to the tooth surface and damage the gear pitting face area of more than 30% depth of more than 10% of the tooth thickness;
6 there is a tooth root or a few at the fatigue crack or a broken tooth.
1 in the root of the hoisting mechanism of the first gear shaft wear more than 10% of the original thickness of the tooth,hoist gantry crane the rest of the shaft of the gear tooth wear more than the original thickness of the fox;
2 carts (car) the first shaft gear reducer operating agencies wear more than 15% of the original thickness of the tooth,steel crane the rest of the shaft of the gear tooth wear more than the original thickness;
3 open gear wear is greater than 30% of the original tooth thickness;
4 lifting red hot or molten metal, acid,bridge gantry crane explosives, flammable and toxic substances such as crane gear scrapped according to the above criteria accordingly halved;
5 due to the tooth surface and damage the gear pitting face area of more than 30% depth of more than 10% of the tooth thickness;
6 there is a tooth root or a few at the fatigue crack or a broken tooth.
Lifting tire maintenance process should pay attention to use what issues
Lifting tires for your analysis process should be maintained in the use of primary attention to the following three points:
1 Pressure Normal
The tire pressure must be maintained properly. Pressure is normal, tread contact area with the road,sino hoist bear the load evenly, normal wear and tear, if the pressure was too low, the tire stiffness degradation, bearing deformation after serious because the tire shoulder wear increased local ground deformation will be serious carcass caused fever, fatigue caused by cords, and other early loss carcass stratification; if pressure is too high, will tire stiff, elasticity, cords and broken due to excessive stretching, and because of the ground area smaller, accelerated tire crown local wear and increasing the load per unit area, causing early damage or puncture,overhead bridge crane this phenomenon is particularly serious in summer. Therefore, the driver should pay attention to before work check the tire pressure, insufficient to timely inflated.
2 smooth start-up and shutdown
Machinery at the very start, tire rotation by a sudden standstill, if starting excessive speed, tire and road generates intense friction, can accelerate tread wear. Therefore, construction machinery started, not too much should tie loose clutch and accelerate properly,overhead gantry crane so that the machinery started slowly and smoothly without shaking to avoid dragging the tire and the ground accelerated tread wear.
3 Maintenance timely
Machinery in motion, if there is weakness, operational difficulties, body tilt, abnormal noise, jitter or a burning smell, immediately stop and check tire condition. Way to rest, you should check the tire pressure and temperature is normal, the wheel nut is loose, the tire is being scratched and so on, and carefully check whether the debris embedded in the tread, if it is found to be promptly removed.
1 Pressure Normal
The tire pressure must be maintained properly. Pressure is normal, tread contact area with the road,sino hoist bear the load evenly, normal wear and tear, if the pressure was too low, the tire stiffness degradation, bearing deformation after serious because the tire shoulder wear increased local ground deformation will be serious carcass caused fever, fatigue caused by cords, and other early loss carcass stratification; if pressure is too high, will tire stiff, elasticity, cords and broken due to excessive stretching, and because of the ground area smaller, accelerated tire crown local wear and increasing the load per unit area, causing early damage or puncture,overhead bridge crane this phenomenon is particularly serious in summer. Therefore, the driver should pay attention to before work check the tire pressure, insufficient to timely inflated.
2 smooth start-up and shutdown
Machinery at the very start, tire rotation by a sudden standstill, if starting excessive speed, tire and road generates intense friction, can accelerate tread wear. Therefore, construction machinery started, not too much should tie loose clutch and accelerate properly,overhead gantry crane so that the machinery started slowly and smoothly without shaking to avoid dragging the tire and the ground accelerated tread wear.
3 Maintenance timely
Machinery in motion, if there is weakness, operational difficulties, body tilt, abnormal noise, jitter or a burning smell, immediately stop and check tire condition. Way to rest, you should check the tire pressure and temperature is normal, the wheel nut is loose, the tire is being scratched and so on, and carefully check whether the debris embedded in the tread, if it is found to be promptly removed.
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