The previous article introduced the selection of crane rails, three commonly used installation and fixing methods, and fixing methods, and potential safety hazards that may arise. This article will focus on the impact of several parameters such as the clearance of the rail top height deviation, the position deviation of the track joint, and the deviation of the gauge on the performance of the crane. You can click on the link in the previous article to jump directly to the corresponding article location. https://www.glorycranerail.com/effect-of-track-on-crane-performance-i/
1)The influence of track height on crane performance.
If the height difference of the crane track is out of tolerance, it will have an important impact on the performance of the crane. The main performance is to change the stress of the main girder of the crane. If it is within the scope of elastic deformation, that is, the track does not occur plastic deformation, then the crane in the process of operation, especially in the frequent point state, the track and the crane is easy to produce resonance, in the process of operation to produce this vibration will be very dangerous.
Due to the existence of the height difference of the track, the main girder of the crane has a certain dip Angle. In this way, the crane’s dead weight and the load it lifts will produce a component force F in the direction of the main beam of the crane. Because there is a certain gap between the crane wheel and the track, the crane will inevitably move to section B under the action of this component force. The inner rim of the B end wheel or the outer rim of the A end wheel is in close contact with the track to produce friction, resulting in biting the rail which affects the service life of the wheel and the track, increases the running resistance of the mechanism, and may cause derailment in serious cases. For gantry crane, it will not only produce the phenomenon of rail gnawing as described above, but also change the mechanical structure of the leg and main beam, affecting the stability of the whole crane. So the impact of the track height difference on the crane is very huge.
No matter for the measurement of camber value on the crane main beam newly installed pr in-use, we generally calculate the upper camber value by using the difference between the average elevation of the two ends of the main beam and the middle elevation of the main beam. For example, the camber value is (e)/2. But if the difference between the height of the track installation is too large, this method can not b used, otherwise there will be a large error. If the upper camber value of the crane is in the critical state of qualified and unqualified, conclusive errors will occur. In the above situation, the number of measuring points can be increased, the coordinate system can be established, the coordinate system can be established, the curve of the main beam can be drawn, and the correct function relation y=/(x) can be established, and then the correct camber value can be calculated through this function relation. The real camber value of the crane ca also be obtained by solving the corresponding triangle.
If the newly installed track is well controlled, the above problems will generally not occur. However, after the crane has been running for a period of time, due to changes in the track support beam or foundation, the daily inspection and maintenance is not timely, or the crane is reinstalled using the original old track. This happens easily.
2)Influence of clearance of track joint, track height and lateral deviation on crane performance.
The joint gap of the track is generally not more than 2mm, and the height and lateral deviation of the track is not more than 1mm. If it is out of tolerance, the biggest harm to the crane will be vibration and noise. In order to further reduce vibration and noise, control the installation tolerance within the range required by the standard, fill the joints of the track. And the distance between the track joint and the joint of the support beam is greater than 100mm, and the horizontal distance between the joints of the two rails is greater than 500mm.
3)Influence on electrical performance
We know that the bridge crane is a kind of electromechanical equipment, and it must be grounded according to the requirements of the standard specification. The grounding protection of hoisting machinery mainly has two parts: the grounding of electrical equipment and the grounding protection of metal structures. The grounding of electrical equipment is based on the metal structure as the grounding trunk, that is, the metal shell of the electrical equipment is connected to the metal structure. The grounding of the metal structure mainly refers to the connection of the metal structure of the whole crane to the ground. Since the crane is in motion during operation, it is common practice to use the trolley track as the connection body between the metal structure of the crane and the grounding body (or zero line), and connect the entire metal structure of the crane as a whole through wheel contact. Therefore, the track plays a vital role in the ground protection of the crane.
In order to ensure the reliability of connectivity, the track must be reliably connected with the wire in accordance with the requirements of the provisions(that is, the track joint id good jumper), so that it becomes an organic whole, and then connected with the ground body or the neutral line, and make the grounding resistance meet the standard requirements. There should be no less than two grounding devices on each side of the track of the crane with lightning protection requirements in the open air, and the grounding resistance should meet the standard requirements. According to the requirements of the need for repeated grounding should be repeated grounding treatment. Check and maintain connections in a timely manner to ensure effective grounding protection.