Gantry Crane Introduction

Gantry cranes are a variant of bridge cranes. In the port, it is mainly used for the loading and unloading operations of freight yards, yard goods, and bulk cargoes. Its metal structure is like a gantry frame, carrying two feet under the main beam, and can directly walk on the track of the ground. Both ends of the main beam can have an outrigger cantilever beam. The gantry crane has the characteristics of high site utilization, large operating range, wide adaptability, and versatility, and is widely used in the port cargo yard.

1. Types of gantry cranes Gantry cranes are generally classified according to the gantry structure, main beam form, and spreader form.

(1) According to the structure of the door frame, it is divided into (a) full-gantry cranes: the main beam has no overhang, and the trolley is carried out within the main span.

(b) Semi-gantry cranes: The height difference of the legs can be determined according to the civil engineering requirements of the site of use.

(c) Double-overhead gantry cranes: The most common form of structure is the rational use of the structure's force and the effective use of the site area.

(d) Single cantilever gantry crane: This type of structure is often chosen due to site constraints.

(2) According to the main beam structure points (a) Single main beam gantry crane: The single main beam cantilever gantry crane has simple structure, easy manufacture and installation, small self-quality, and the main beam is mostly eccentric rail box structure. Compared with double-girder gantry cranes, the overall stiffness is weaker. Therefore, when the weight Q≤50t and the span S≤35m, this form can be used. The single main beam crane has two types of door legs: L-shaped and C-shaped. The L-shape is easy to manufacture and install, and the stress conditions are good. The quality of the L-shape is small. However, the space for lifting cargo through the legs is relatively small. The C-shaped legs are made to be inclined or curved so as to have a large lateral space for the cargo to pass through the legs.

(b) Double-girder bridge cranes Double-girder bridge cranes have strong bearing capacity, large span, good overall stability, and many varieties, but their own quality is larger than single-girder gantry cranes with the same weight, and the cost is also high. Higher. According to the different main beam structure, it can be divided into two forms of box beam and truss. At present, generally more box-shaped structure.

2. The representation of the gantry crane represents the model of the gantry crane using the four major elements of code, rating, mass, span, and work level.

(1) Code Meaning M: Indicates the gate type. The symbol after M is a double beam gantry crane. Its symbols are: MG, ME, MZ, MC, MP, MS, plus two symbols for the single main beam gantry crane, its symbols are: MDG, MDE,

MDZ, MDN, MDP, MDS.

MG—double-beam single-car hook gantry crane;

ME - double beam double trolley hook gantry crane;

MDN—single-girder single-grab grapple grab gantry crane;

MDS—Single girder trolley three-purpose gantry crane.

3. Selection of gantry crane (1) Selection of single main beam and double girder gantry crane Under normal circumstances, the lifting capacity is below 50t and the span is within 35m. There is no special use requirement and a single girder type should be used. If it is required that the width of the door legs is large, the working speed is high, or heavy items or long and large pieces are often hoisted, double-girder gantry cranes should be selected.

(2) Span and Cantilever Length The span of gantry cranes is an important factor affecting the quality of the crane itself. In the selection, the span should be minimized on the premise of satisfying the conditions of equipment use and meeting the span series standards.

(3) The principle of wheel alignment (a) can meet the stability requirements of the gantry in the direction of the crane track;

(b) The size of the cargo must be able to pass through the leg flat steel frame smoothly;

(c) Pay attention to make the distance between track B and span S in a certain proportion, generally take the track distance B = (1/4 - 1/6)S.

(4) Determination of the gantry crane spacing In operation, there should be a certain spatial dimension between the external dimensions of the gantry crane and the cargo of the yard and the passage of the transport vehicle to facilitate loading and unloading operations. When a typical transport vehicle is loaded or unloaded within a span, it should be kept at a distance of more than 0.7m from the door legs. When the spreader is not working, it should have a spacing of more than 0.5m from the transport vehicle, and when the goods pass the door legs, there should be a spacing of more than 0.5m.

(5) The selection of gantry crane electrical equipment It should comply with the relevant provisions of the general gantry crane GB/T14406-1993.