| 摘要 |
PURPOSE:To execute pressure seaming with a sufficient seaming strength, by raising the axial strength by pressurizing the inside of a can and pressure-reducing the outside of the can, at the time of seaming the can. CONSTITUTION:A can 20 is supplied onto a lifter 16, and a can cover 21 is supplied to a can cover supporting member 7. A chamber 15 is allowed to ascend and its upper end outside peripheral part 17 is allowed to adhere closely to the lower end outside peripheral part of a housing 2. The lifter 16 is allowed to ascend and the can cover 21 is fitted to an opening part of the can 20, and the can cover 21 is fitted to a seaming chuck 3. When the lifter 16 is ascending, a space of a seaming part surrounded by the housing 2 and the chamber 15 is pressurized by supplying air from an air supply port 8, and the inside of the can 20 and the space of the seaming part are pressurized to an equal pressure. At the time point when the can cover 21 has been chucked, a changeover valve 9 is switched to an exhaust side, the space of the seaming part is exhaust and pressure-reduced to the atmosphere side, and a pressure difference is generated between the inside and the outside of the can 20. As a result, the axial strength of the can 20 is improved. In this state, seaming is executed. According to this method, even in case of the can 20 of a soft material, it is prevented that buckling occurs, and seaming can be executed with a high sealing performance.
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