Technical Description of Bridge Crane with Grab
1.1 Applicable working conditions
The bridge crane with grab is applicable to the working conditions requiring grab and hook at the same time. It is used for lifting materials, installation and maintenance of equipment.
1.2 Main structural features
Main structure: the whole equipment is mainly composed of bridge, long traveling mechanism, trolley, grab, cab and electrical equipments.
The crane adopts the structural type of double beam, double rail and single trolley.
The crane trolley is equipped with a set of grab type lifting mechanism and hook type lifting mechanism.
The crane is mature and reliable, easy to operate, stable operation and advanced technology. It is a mature product of our company for many years.
2 Main design, manufacturing and inspection standards
1) GB/T 3811—2008 Crane Design Code
2) GB 6067—1985
Safety Regulations for Hoisting Machinery
3) GB/T 14405—1993 General Purpose Overhead Crane
4) GB/T 10183—2005
Tolerances for Bridge and Gantry Crane Fabrication and
5) GB/T 5905—1986
Crane Test Specifications and Procedures
6) JB/T 4315—1997 Crane Electric Control Equipment
7)GB/T 6974-1986 Hoisting Machinery Terminology
Technical Performance and Acceptance Documents of
Cranes and Lifting Machinery
Cab of Crane First Part
3 Main technical data
4 Technical description of main structure
The bridge is the main load-bearing component of the crane, which adopts the structural form of double beam and double rail, with the main beam and end beam as the main load-bearing parts, supplemented by trolley track, walking platform, railing, ladder and other auxiliary metal structures.
The main beam is a normal rail box structure. The section of the main beam is systematically analyzed and calculated by ANSYS finite element calculation method to ensure that it has sufficient strength, stiffness and overall stability.
The main stress-bearing parts of the main beam are made of Q235-B (Q 345-B), and the minimum thickness of plate is not less than 6mm.
The transverse butt welding joints of the cover plate and web plate of the main beam and end beam and the connecting welds between the web plate and the cover plate shall adopt submerged arc welding or gas shielded welding, and NDT shall be carried out after welding.
The camber of the main beam is (1～1.4)S/1000, and the position of the maximum camber is controlled within 1 / 10 of the middle of the span.
The trolley track adopts the whole track with welded joints to ensure good operation of the trolley.
The end beam is a box structure, and the connection between the end beam and the main beam is rigid. Where the end beam is disconnected, it is connected with high-strength bolts. Each connecting plate is positioned with reamed bolts, the positioning number matching marks have been made when leaving the factory.
The tread of bridge walking platform adopts anti-skid checkered plate with a thickness of 3mm.
The walking platform of the bridge are provided with railings with a height of 1050mm. The railings are provided with horizontal cross bars with a spacing of 350mm, and the bottom is provided with toe guard with a height of 70mm. Any part of the railings can bear 1 kN (100kgf) load from any direction without plastic deformation.
In order to facilitate transportation, loading and unloading and site installation and hoisting, lifting lugs and holes for hoisting are set on the main components. The strength and location of these lugs and holes shall fully consider the safety and convenience of hoisting.
The cab is the workplace where the operator operates the crane. It adopts closed (open) and tempered glass (thermal insulation) cab. The design of its structural not only considers various functional requirements, firmness, durability, safety and reliability, but also considers good vision, comfort and beauty, so that the driver feels comfortable during operation. A cold and warm air conditioner is equipped indoors, and the temperature in the cab is maintained within the range of + 20 ~ 35 ℃, so that the driver can work in a good environment.
In order to ensure the wide field of vision of the operator, tempered glass is installed on the front upper, front lower side wall and rear wall of the cab. The maximum elevation angle of the driver on the seat is 55 ~ 60 °, the maximum depression angle is 70 ~ 75 °, the maximum front viewing angle of the driver is 120 °, and the front viewing angle of seat can be up to 270 °.
The framework of the cab is welded by rolled section steel and stamped sheet steel, and the floor is paved with insulating rubber carpet. The inner and outer sides of the glass can be wiped safely and conveniently. The upper part of the window frame is fixed with the cab frame.
An alarm is also set in the cab to ensure the safe operation of the crane.
The layout of various settings in the cab fully considers the convenience of driver maintenance and operation, activity space and smooth walking. Ensure that the driver can withdraw quickly and safely in case of accident.
4.3 Long traveling mechanism
The long traveling mechanism is supported by X wheels, and two sets of independent driving systems are used to drive the crane respectively
The transmission type of long traveling drive system is: one motor drives a reducer through gear coupling and transmission shaft, and the low-speed shaft of the reducer is connected with wheel shaft by coupling. The driving wheel ratio is 1:2. When starting, the driving wheel does not slip, and when braking, it is stable and reliable. This structure is convenient for installation, maintenance and disassembly of various components of the drive system.
The selection of wheel diameter and material of crane operating mechanism is based on the maximum bearing force of wheels under the most unfavorable working conditions to ensure that some wheels will not be overloaded.
4.4 Hoisting mechanism
The crane trolley is equipped with a set of grab and hook as lifting mechanism.
Grab hoisting mechanism: two sets of double drums are adopted, which are arranged symmetrically. The work is done by the hoisting motor, the speed is changed by the reducer, and then the drum is driven by the drum coupling. Through the steel wire rope winding system, the support rope and open and closed rope of the grab are operated respectively to control the lifting, lowering, opening and closing of the grab.
Hook type lifting mechanism: work is done by the lifting motor, speed is changed by the reducer, then the drum is driven by the drum coupling, and the lifting of the hook is completed through the steel wire rope winding system.
The braking of the lifting mechanism adopts the scheme of supporting braking and controlling braking. The control braking adopts electrical braking, and the supporting braking is to set the brake on the high-speed shaft of the motor for braking, so as to make the braking of the lifting mechanism stable, safe and reliable.
4.5 Cross travel
The cross traveling mechanism is supported by four wheels, and a set of independent driving system is used to drive the trolley centrally.
The transmission type of the trolley drive system is: a motor drives a vertical reducer through the gear coupling. The two low-speed shafts of the reducer are connected with the two wheel shafts by the coupling and transmission shaft. The driving wheel ratio is 1:2. When starting, the driving wheel does not slip, and when braking, it is stable and reliable. This structure is convenient for installation, maintenance and disassembly of various components of the drive system.
The wheel diameter and material of the cross traveling mechanism are selected according to the maximum bearing force of the wheel under the most unfavorable working conditions to ensure that some wheels will not be overloaded.