Cantilever gantry crane is commonly found in open storage areas such as freight yards and ports to lift and transfer bulk cargoes and piece cargoes. The span can have one or two cantilevers depending on your specific application. Double cantilever gantry crane is the most common structural form that is subjected to the force reasonably and also effectively utilizes the working area. Single cantilever is used where the work site is constrained.
Cantilever Gantry Crane Specifications
Single girder gantry crane with one cantilever parameters:
- Load capacity: 3-20t
- Span: 8-35m
- Lifting height: 6-18m
- Lifting speed: 0.33-8m/min
- Trolley running speed: 20m/min
- Crane running speed: 20m/min
- Work duty: A3, A4
Double girder gantry crane with cantilever parameters:
- Load capacity: 5-500t
- Span: 18-35m
- Lifting height: 6-18m
- Lifting speed: 1.5-11.5m/min
- Trolley running speed: 10-40.1m/min
- Crane running speed: 16-50m/min
- Work duty: A3-A7
|Technical Parameter of AQ-MH Electric Hoist Single Girder Gantry Crane|
|Track type||P24||P24 P30||P30 P38||P38||P38 P43|
|Technical Parameter of AQ-MG Double Girder Gantry Crane|
|Track type||P43||P43||P43 QU70||P43 QU70||P50 QU80|
Functions of Cantilever Gantry Crane
The cantilever of a gantry crane is the part beyond the span of the main beam. Its length cannot exceed one third of the span, and electric hoists or trolleys can run on the cantilever. The cantilever can be box type or truss structure according to the structure of the main beam.
Gantry crane with cantilever can increase the working range and improve the work efficiency to a certain extent. It also makes the use of the gantry crane more convenient.
The main function of the cantilever is to increase the convenience of operation and easy unloading. If the vehicle is not very convenient to park in the middle of the main beam, you can park it outside, and let the hoist trolley run to the cantilever end for lifting, loading and unloading operations. In this way, you can load and lift cargo while not wasting space within the span.
Because the legs of some double girder gantry cranes with cantilever are tilted inwardly in the plane of the gantry frame, which generates an inward horizontal component force, these cranes usually have saddles on the main beams to prevent the legs from deforming inward.
Some gantry cranes do not require a cantilever, such as indoor use, which is inconvenient to use. The use of the cantilever depends on your specific situation.
How to Size A Gantry Crane
It is very important to determine the size of a gantry crane when designing and manufacturing a crane.
First of all, determine the span and cantilever length of the crane:
The span is the distance between the centers of the crane tracks, which is determined according to the use conditions and process requirements.
The size of the cantilever also depends on the use requirements. The reasonable length of the cantilever should be determined according to the principle of equalizing the large bending moment of the cantilever and the mid-span bending moment under the action of its own weight and active load. Or you can also choose not to make the cantilever and saddle according to the actual situation.
Determine the lifting height:
Lifting height refers to the vertical distance from the rail of the cart to the bottom of the spreader when the spreader is raised to a high position, the unit is m. Lifting height depends on the type of goods to be loaded and unloaded and the type of spreader used. For example, for grab bucket gantry cranes or gantry cranes used for loading and unloading bamboo and wood, the lifting height is required to be larger.
When determining the lifting height of a gantry crane, one important thing to consider is to reduce the lifting height as much as possible under the premise of meeting the requirements of usage. Because when the lifting height is large, the crane weight increases, and at the same time, the swing of the load will increase under the action of horizontal force, which will adversely affect the distribution of wheel pressure.
Determine the size of the legs:
Generally, when the span of the crane is within 30m, rigid legs are used on both sides. When the span is greater than 30m, flexible legs are used on one side, and rigid legs are used on the other side to compensate for temperature-induced deformation or the error of the crane’s deflection.
Determine the height and width of the girder section and the wheelbase:
Generally, the cross-section height of the main beam is determined according to the use conditions and process requirements. It also needs to be checked for strength and stiffness.
Criteria that determine the wheelbase: the stability of the crane in the direction of the running track; the size of the loads can pass through the outrigger plane frame; consider the span length.
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