A special reason for bad paper delivery

The YP4A-1 4-color offset press produced by the Beijing People's Printing Machinery Factory, which was acquired by the Beijing People's Printing Machinery Factory in 1996, has experienced a series of poor paper collection failures. After other people made adjustments such as tightening the chain, the normal work was less than 10 hours before the old one relapsed.
The failure performance is as follows: When the speed is below 6000, the teeth only have one or two teeth at one end of the row. Sometimes the printing speed increases slightly, and the entire row of teeth almost does not pick up paper and there is no regularity.
When I started overhauling, the operator had suggested that the delivery platoon opener had significant rocking as each opener passed. It was found that the fastening nut of the open-die fixing bar outside the machine wall plate had fallen off into the oil. However, after tightening it, there was no improvement in the poor delivery of the teeth. Although there is no fundamental change in adjusting the balance force of the row of enamel teeth at the delivery table several times, even when adjusted to be as consistent as possible with other normal teeth, the delivery effect is still not the same.
Then, where is the root cause of the fault? After splitting, I think that part of the teeth of the tooth row cannot hold the paper, and it is related to the poor side of the paper when the drum is handed over, and the other 5 rows of teeth are basically good to show that the hand-over time is basically normal. The problem is definitely on this tooth row.
Later on at the teething point at the delivery station, I occasionally heard a slight, irregular click as the tooth row turned on the turn of the delivery sprocket. After repeated trial listening, the other teeth had no such unusual abnormal sound. This indicates that the tooth row has abnormal friction when running and that there may be obstacles when the tooth row moves on the chain. So, I decided to take the tooth from the chain and check it.
The point car moves the teeth diagonally above the delivery roller, ie where the chain flat rails are connected to the descending diagonal rails, where the threaded long pins that connect the bar head cover to the chain are retracted to the chain. When it is flush, the end cap of the end row can be taken out obliquely upwards, and then the teeth row can be pulled out to the transmission surface, and the shaft head cover of the operation surface can be set out from the threaded long shaft and the teeth can be removed. Take it from the machine.
After cleaning both ends of the row of teeth, it was found that the outer end face of the two-jaw shaft head cover had obvious friction marks with respect to the link pin shaft and the rivet head at the center of the shaft head cover. This proves that the tooth row does not have an irregular frictional sticking phenomenon each time it interacts with the roller.
In this regard, I use angular grinding wheels to properly abrade the relevant chain pin rivets under fire safety conditions.
After finishing the assembly and running to 7000 prints/h (because the speed limit is 7000 in/h), the tooth is completely normal.
The above description shows that the root cause of the defective delivery failure of the original row of teeth is that the row of teeth has irregular frictional sticking when the chain runs and turns.