What Is a Rubber Tyred Gantry Crane?

Gantry crane is a variant of bridge crane. In the port, it is mainly used for loading and unloading of outdoor cargo yards, storage yards, and bulk cargoes. Its metal structure resembles a door-shaped frame. Two feet are installed under the main beam, which can directly walk on the ground track. The main beam can have outriggers at both ends. Gantry cranes have the characteristics of high site utilization, large operating range, wide adaptability, and strong versatility. They have been widely used in port cargo yards.

Gantry crane, commonly known as gantry crane, gantry crane. It is the pictograph of gantry crane, which is actually gantry crane. Gantry cranes are generally used for project installations, such as large equipment, but require a large site. Many times it is used for heavy loads. Its structure is as the word says, like a gantry, the track is tiled on the ground, old-fashioned motors at both ends, dragging the crane to move back and forth on the track, many gantry types also use frequency conversion motors and Servo-driven. ^[1]

The gantry crane can be classified according to the structure of the door frame, the form of the main beam, the structure of the main beam, and the type of use.

According to the industry standard GB / T14406, the gantry crane is mainly composed of the following parts

I. Selection of gantry cranes It complies with the relevant regulations of general gantry cranes GB / T14406-1993 and GB5905-86.
In general, the lifting capacity is below 50t and the span is within 35m. There is no special use requirement, and the single main beam type should be used. If the width of the door legs is required to be large, the working speed is high, or heavy and long pieces are often hoisted, then a double-beam portal crane should be selected.
Second, span and cantilever length <br /> The span of the gantry crane is an important factor affecting the quality of the crane itself. In the selection, the span should be reduced as much as possible on the premise that the equipment use conditions are met and the span series standards are met.
Third, the determination of the track
(A) It can meet the stability requirements of the mast in the direction of the crane track;
(B) The overall dimensions of the goods must be able to pass through the flat steel frame of the legs smoothly;
(C) Pay attention to make the wheelbase B proportional to the span S. Generally, take the wheelbase B = (1 / 4-1 / 6) S.
Fourth, the determination of the size of the distance between the gantry crane < brIn work, there should be a certain space size between the external dimensions of the gantry crane and the cargo and transport vehicle passageway of the yard to facilitate loading and unloading operations. When loading and unloading within the span of a general transport vehicle, the distance from the door legs should be kept at least 0.7m. When not working, the spreader should have a distance of more than 0.5m from the transport vehicle, and the cargo should have a distance of more than 0.5m when it passes through the door legs. ^[1]

One,

Gantry crane walking failure and its maintenance

1. Reason

Gantry crane

The main reason for walking failure is that because of the high level of structural rigidity of the entire gantry crane, normal operation, especially during the execution of the walking action, it is difficult to ensure that the four fulcrum points are in the same plane. The connection mode of the walking motor oil circuit is parallel. At the same time, considering that the pressure value of the hydraulic system will be affected by the load force factor, the unevenness of the track results in different pressure levels required to drive the hydraulic motor. For a walking wheel with the smallest pressure value, it first performs a turning action. In this way, the traveling wheel may be caused to be suspended, and the corresponding drive motor load value is minimized, and the idle or stop is not continuous.

2.Treatment measures

In the case of a walking failure of the gantry crane, the specific maintenance methods can be considered from the two aspects of the configuration of the number of driving wheels and the oil connection method:

Path one: Increase the four driving wheels provided by the original gantry crane to eight, and each two driving wheels are connected by pins to form a balanced driving wheel to ensure that the walking wheels can still accompany the track fluctuations under the track fluctuations , Increase the contact area between the two (the improved connection diagram is shown in Figure 2 below).

In the second way, the motor oil circuit connected in parallel is changed to the oil circuit connection mode in which series and parallel are combined. In this way, it is ensured that at least one motor at each fulcrum drives the wheels to do work, avoiding the problem of idling and slipping due to uneven force. ^[2]

Failure of wheel gantry of gantry crane and its maintenance

1. Reason

There are two main factors that cause the wheel track failure:

First of all, the problem of wheel deflection in the horizontal direction mainly refers to the fact that during the installation of the wheel, the control of the horizontal deflection is not taken seriously. The track centerline and the wheel centerline do not overlap, forming a certain angle. In the case where the included angle is greater than 0.5 °, the failure of the wheel track will occur.

Secondly, the problem of vertical wheel deflection mainly refers to the influence of the structural deformation factors of the gantry crane. The angle between the vertical line and the center line of the wheel tread is poor, resulting in an increase in the wheel's running radius and a significant distance per week. increase. In addition to the above factors, deviations in the transmission performance of the transmission system as well as the design and installation defects of the track itself will increase the incidence of wheel and track failures.

2.Treatment measures

First of all, considering that the track will be subjected to various external forces to varying degrees during the actual operation of the gantry crane, which will cause problems in displacement and deformation, it will induce wheel track failure under long-term effects. Therefore, in order to ensure the good working condition of the track, it is necessary to pay attention to the flexible adjustment of the track. Before the track adjustment, check whether there are any cracks or cracks on the outer surface of the track. At the same time, measure the track gauge and adjust the height of the whole process. The straightness of the track is corrected by the wire rope. Then check whether the bolt or the track plate is loose. If the deformation is slight, you can directly adjust it locally. If the deformation is serious, you should replace it with a new track or expand the track foundation. Secondly, the installation accuracy of the wheel set needs to be controlled reliably. The commonly used methods are the following three types: First, the application of large rim height: according to the original height, floating 50%, to improve the wheel rim under stress The pressure contact condition on the side of the track reduces the stress level, avoids rim wear, and improves the durability. Second, adjusting the wheel group gauge: In view of the current relevant design specifications, it is required that for gantry cranes in the general sense, In other words, the gauge error should be strictly controlled within the range of ± S (span) / 1000. There are two specific adjustment methods: adjusting the fixed key plate made of the wheel set bearing; adjusting the length of the sleeve on both sides of the bearing. The adjustment range is recommended to be controlled within 8.0 to 10.0mm. Third, the diagonal adjustment of the wheel set is reasonably adjusted. In view of practical work experience, it is considered that in order to ensure the coaxiality of the mechanical transmission system and reduce the maintenance workload, it should be passive. Adjust the wheels, avoid adjusting the driving wheels as much as possible, and solve the problem of diagonal installation. ^[2]