Abstract: Fire ventilation pipe is one of important parts of building for smoke exhaust and ventilation. At present, sewing the two sides of the rectangle fire ventilation pipe by manual operation brings to low efficiency and high labor intensity. Therefore, it is necessary to finish automatically the process with machines. However, the rectangular fire ventilation pipe has many characteristics, including various?sizes, poor body stiffness and easy deforming of thin wall, which lead to the difficulty to sew automatically the pipe. In order to solve the problem of automatic sewing fire ventilation pipe, a method is proposed that sews the two sides of fire ventilation pipe with hydraulic double heads and double rolling heads driven by hydraulic mechanism. The two right angle ends of the stitching edge are used for positioning and clamping, which solves the problem of requiring multi specification tooling and frequent replacement of tooling during processing; Hydraulic double ends are used to clamp and support the rolling surface, which effectively increases the stiffness of pipe and solves the problem of deformation of the fire ventilation pipe during rolling; The rolling head uses a gradual four-wheel design to reduce the pressure on the pressed surface and ensure that the fire ventilation pipe is not deformed during one -time sewing. The experimental results of the prototype show that the automation can meet the side sewing process requirements of fire ventilation pipes of different specifications, the processing time is less than 1 minute, and the efficiency is improved by more than 80%.

Key words: fire ventilation pipe; roll forming; automatic sewing machine