The implementation of " going out" strategy, and actively expand the international footprint

  Implementation of the enterprises "going out " strategy, carrying out international capital operation "Dances with Wolves " is the transformation of economic development to the country 's positive practice .
    Chinese enterprises international operations provides us with an opportunity to close in the international market ,hoist gantry crane will effectively enhance the international competitiveness of Chinese enterprises , and promote China from a manufacturing power to create powerful shift from extensive , quantity to quality , and efficiency transformation.
Throughout the dominating international world-class enterprises, they have similar characteristics - the main business income in the world, with a global brand image and leading-edge technology , leading the industry change and innovation , with advanced management tools and unique development strategy , with professional, professional staff. These companies provide products and services to the world , while also convey their country 's culture.
    China's  Steel crane  manufacturing industry , the general supply of spare parts is very adequate , however , such as transmission components , control components , diesel engines and hydraulic parts and other key high-tech, high value-added core components of the primary still dependent on imports, serious restricting China's equipment manufacturing industry to the development of high- technology products . With China's economic structural adjustment, change the mode of development to accelerate the pace of domestic enterprises have been trying to break through the key components of the core technology , more and more Chinese enterprises to the sea voyage , to strengthen international capital operation , hoping to obtain cross-border mergers and acquisitions abroad advanced technology to enhance their core competitiveness.
    Indeed, over the 2012 , China 's construction machinery industry staged more than the case of overseas mergers and acquisitions of Chinese enterprises "going out " shows not only its own brand image , it is the country's image .
To sum up, China issued two sessions on " construction machinery " sound , the sound piercing the current construction machinery industry, the existence of various deficiencies and shortcomings , but also for China 's future development of construction overhead gantry crane  clear . Waits for no man , we need to further cultivate internal strength , a positive innovation , efforts to expand overseas markets , to participate fully in international competition. Only in this way , China 's construction machinery to be able to really strong , we are able to China from a large industrial country into an industrial powerhouse !

The safe operation of cranes

Truck crane is mounted on the chassis or regular car a special  gantry crane  chassis on its driving cab and crane cab be set separately. This crane has the advantage of good mobility shift rapidly. Disadvantage is that when working legs, can not load driving, do not fit in soft or muddy work on site. Truck crane lifting operation is part of the general or special vehicle mounted  bridge gantry crane  chassis, and has a truck driving performance. In order to meet the requirements of driving under adverse conditions, derived with off-road performance truck cranes. Crane in front of prohibited jobs, that the center of gravity hook lifting operation shall not exceed the rotation center of the front leg (left) ground connection to the centerline. In the starting weight indicating device malfunction can not be used with the case should be lifting performance shall be determined from the weight of the table, we must standardize  hoist gantry crane  operation behavior, to ensure safe and correct. Lifting heavy objects are not allowed off the arm; must drop the weight down to re-arm rises when the job; fall when the throttle arm is smaller, Raise when the throttle should be large; rotary action should be smooth, not allowed to sudden stops; Job ago to carefully check, prohibit the use of substandard steel wire rope and lifting chain; lifting heavy objects are not allowed off the arm; must drop the weight down to re-arm rises when the job; fall when the throttle arm is smaller.

Frequency converter in the crane electronic control system application

Introduction
Lifting industry using PLC- inverter gradually in recent years to promote and popularize , especially in large lifting equipment , with PLC program control to replace the traditional relay - contactor control ; replaced with a variable speed motor winding series resistance rotor speed ; asynchronous motor with inverter motor or replace the motor winding , coupled with advanced fieldbus technology and HMI system to improve the control accuracy and stability of the equipment , reduce the failure rate , and the energy-saving effect is remarkable , easy repair and maintenance , improve production efficiency to become a good way .
Control scheme
A large heavy machinery manufacturing plants, bears all the bulky equipment assembly , positioning, docking and other tasks, the  overhead gantry crane  high performance requirements , the use of an overhead crane used QD250/50t siemens S7-400 PLC, ABB inverter , touch screen and other high-performance configuration, application of advanced Profibus fieldbus technology , with encoder feedback direct torque control, and advanced human-machine interface system.
Divided into the main bridge crane hook, deputy hook , carts , trolleys and other four parts. Due to the main  eot crane  hoisting mechanism in most typical applications , control is also the most complex , so the main hoisting example in this chapter detailing its control.
1, PLC
The whole system S7-400 PLC as the core of electronic control , the main power supply module , CPU, input and output modules and interface modules and other components. Acquisition by a limit switch input modules , thermistors, inverter and other equipment fault feedback signal state ; receiving master controller , buttons, switches send control commands concentrated in the CPU operation and program operation result output module and Profibus fieldbus send contactors and inverters perform device to the drive motor , hydraulic brake , cooling fan and other complete various production tasks.
2, Profibus fieldbus system serial communication
Profibus is an open serial communication standard that enables data exchange between various automation components . In this system with S7-400 as the main station to the agencies as a slave drive by DP interface module and RS485 shielded twisted rapid real-time data exchange .
Set the inverter communication parameters :
98.02 = fieldbus communication module activation
51.01 = Profibus-DP field bus type selection
51.02 l = 3 to set the main inverter station address
51.03 = 1500 selected communications transmission rate of 1.5Mbit / s
51.04 = PPO4 select data type 4 ( 6 process data as a standard block )
As a master PLC CPU reads from the slave state of various input information, namely primary l read from the drive status word and actual values, including the drive is ready , power- response operation, the torque verification OK, inverter failure , the actual motor speed and other information ; and write information to a variety of output from the station , about the control word and speed reference written inverter. Including communications test position, from fieldbus PLC system Drive on, the start signal from the host system , fault reset signal and the actual frequency reference and so on. The complex signal conversion , monitoring, feedback process all data transmission via Profibus chain , and CPU quick focus easily .
3 , advanced man-machine interface system
TP270 touch screen and PLC Profibus bus is also used for data transmission and exchange , real-time display and monitor the operational status of the agencies and the voltage, current, torque, speed and other operating parameters , and can use its own real time fault diagnosis system Symptom judge , recording failure of various parameters , so that operators and maintenance personnel can fully understand the state of the system in a timely manner , and may prompt fault information to inspection and maintenance , to achieve accurate and fast troubleshooting effect , the real achieve a human intelligence .
4, the frequency control system
1 ) Lifting conditions and requirements
Hoisting mechanism requires a larger speed ratio and mechanical characteristics of hardness to suit the precise weight lifting requirements ; require a large starting torque ,bridge gantry crane excellent dynamic torque response ability to adapt to sudden load change , ensure that the heavy secondary lifting capacity ; must solve regenerative braking energy feedback and processing, in order to shorten the deceleration stopping time ; slide the hook must solve the problem .
2 ) conversion function application
According to the hoisting mechanism characteristics and technical requirements , the drive uses with a tachometer feedback interface 800 series drives, with ACC 7.2 Special upgrade software , form a closed loop direct torque control, through the pre-excitation function and starting torque setting , the motor starts instantaneous torque up to 300 %, achieved an excellent starting characteristics . built-in brake chopper , external braking resistor , braking process so that the generation of energy through regenerative braking resistor to be released , to achieve the purpose of rapid braking . Using a mechanical brake control function, so that the motor torque and brake release closely with better improve the safety of the equipment , the ability to withstand the impact of frequent starting and reliability also increased significantly .

320T double girder overhead crane

The crane mainly by the box-shaped bridge,  bridge crane  trolley traveling mechanism and electrical control system. Extract device is a hook.
Main beam is off-track width box girder, electrical equipment and traveling mechanism are installed in the main beam interior.
Operation with wireless remote control and two operating cab form. Cab with open, closed two, there are adjustable seat, floor laying insulation pad, windows with tempered glass, with a fire extinguisher, electric fans, according to user requirements heating and air conditioning, transducers, walkie-talkies and other items .
The crane suitable for ambient temperature -10 ℃ ~ 40 ℃, relative humidity less than 85% of factories, warehouses and garages, etc. for loading and unloading lifting work prohibited on the flammable, explosive and corrosive gases filled environment.
The crane mainly by the box-shaped bridge,  hoist gantry crane  trolley traveling mechanism and electrical control system. Extract device is a hook.
Main beam is off-track width box girder, electrical equipment and traveling mechanism are installed in the main beam interior.
Operation with wireless remote control and two operating cab form. Cab with open, closed two, there are adjustable seat, floor laying insulation pad, windows with tempered glass, with a fire extinguisher, electric fans,bridge gantry crane according to user requirements heating and air conditioning, transducers, walkie-talkies and other items .

From the weight of the basic functions of the limiter

From the weight lifting torque limiter limiter and collectively overload protection device. Overload caused by  jib crane  operation is one of the major accident, the light damaged crane parts, so click on overload, structural deformation; heavy causing broken beams, inverted tower, folding arm, the machine overturning a major accident. Using sensitive and reliable overload protection device is to improve the intrinsic safety of the crane, effective measures to prevent overloading the accident.

From the weight of the basic functions of the limiter

1, dynamic load suppression. Overload protection device should be able to distinguish between the actual overload  gantry crane  hanging objects in the normal operation lifting, braking, running and other effects arising from the dynamic load. Hanging objects Guaai (or consolidation with the ground), you should be able to work immediately. Hanging objects caused by the additional dynamic load lifting operation is inherently dynamic phenomenon. Prevent dynamic load effects can be taken latency technologies. However, this delay may be working blind. If within this time stuck hanging objects, the rope tension in a very short time to achieve the degree of damage to the crane, the use of this technology products should solve this problem.

2, automatic job functions. Overload protection devices work properly, you should be able to automatically perform specified functions, should not increase the additional operating the bridge gantry crane  driver.

3, the fail-safe function. Promote product has an automatic safety feature, when failure occurs inside the product, you can send an alarm signal indicative.

General requirements for the design of crane hook

Crane hook is the main component, once corrupted very easily lead to serious injury or death. Therefore, we must strengthen the professional manufacturer of hook and general manufacturing enterprise with a hook in the hook and safety supervision and inspection work.  eot crane  hook design generally requires the following 10 points:

One should consider the use of environmental requirements.

2, should meet the strength, plasticity and toughness, fatigue resistance and shock functional requirements.

3, to meet the requirements of design and technology.

4, forging hook fiber orientation, should seek to comply with a hook shape distribution. Forged hook should be performed after heat treatment.

5-piece hook rolling direction of the laminations and fiber orientation, should strive to be consistent direction of the pressure must be eliminated using cutting heat-affected zone formation.

6-piece body and suspension hook and plywood does not allow access.

7, the use of forged or rolled materials can not meet the performance requirements or difficult to manufacture,hoist gantry crane the use of a casting manufacturing, must demonstrate its use or through practical experience confirms it applies only when permitted.

8, the surface and inside the hook should not be sufficient to impair its usability shortcomings.

9, manufacturing materials and purchased parts hook should have manufacturing units certificate and other technical documents, or should be tested to identify performance qualified before use.

10, after the inspection of the hook, the manufacturer shall make an appropriate position in the hook is not easy to be worn marks, and issue certification. Tag should include at least the rated weight,hoist crane production number, date of manufacture, manufacturing units, the original opening degree hook other items.

Type of crane lifting limiter

overhead bridge crane overload protection devices according to their different functions can be integrated into automatic stop-and-two. Classified according to their institutional forms, there are two kinds of electrical and mechanical type.

Auto-stop type. It refers to lifting the quality of more than nominal weight, they can stop the crane to unsafe direction (lifting, outriggers, drop arm, etc.) continues to operate, while allowing the crane to a safe direction movements.

Integrated lifting limiter. When lifting the quality is reached nominal weight of about 90% can be audible or visual alarm signal, lifting weight of more than nominal weight, they can stop the overhead gantry crane  unsafe direction to continue action, concurrent sound and light alarm signals, and allow the crane to a safe direction movements.

Electric-type lifting limiter. Refers to mechanical energy to electrical energy conversion between, to achieve protection. That the detected amount of the load and other mechanical converted into corresponding electrical signals, and then zoom, comparing, computing and processing. Habits become electronic, electric, electromechanical and microprocessor-based products are of this.

Mechanical load limiter. Refers to the conversion of mechanical energy and switch between fit to achieve protection.bridge gantry crane Machinery products is relatively simple, using leverage, eccentric, spring or hydraulic system to detect load, through limit switch (control valve) the product movements.