Toggle seat,upper

First stop the machine and clean the crack surface; use dye penetrant or magnetic particle inspection to confirm the crack direction and length. If the crack does not extend to the main load-bearing rib plate and is short, it can be repaired by welding per procedure. If it penetrates the main load-bearing zone or deformation exceeds limits, the frame must be replaced.

Common causes include: insufficient or deteriorated lubricating oil, improper bearing clearance, excessive bearing housing concentricity deviation, seal failure allowing dust ingress, and poor cooling water flow. Check lubrication status, assembly precision and the cooling system item by item.

Usually caused by excessive wear clearance in eccentric shaft bearings, worn moving jaw bearing bushings, insufficient tie rod spring tension, or worn toggle plate and toggle plate seat. Measure each fit clearance and replace parts exceeding the limit.