The 30- pressure chain block, also known as the chain linker, is suitable for the general mining SGB420 / 30 type scraper conveyor and is located on the head frame of the transmission section to prevent the chain from jumping when the scraper chain is running on the head to ensure scraping The safety of the operation of the trigger. When the scraper chain jumps, it is easy to cause the scraper chain to break, which will bring serious safety accidents.