Cable tray is a commonly used support and protection device for cable laying in electrical equipment. As a commonly used cable tray, trough type cable tray has been widely used. In order to prevent some materials from falling inside the tray, a cover plate is usually installed on the cable tray. By setting a cover plate, materials can be prevented from falling inside the tray. However, after falling on the cover plate, materials will continue to accumulate over time, It has a significant impact on the cover plate or bridge: for example, the contact position between the material and the cover plate is prone to rust due to lack of air circulation, and excessive material accumulation increases the load bearing capacity of the cover plate and damages the cable bridge.