JP2863591B

PURPOSE:To improve the sealing property and reduce the degree of risk in emergency by preventing the vertical sliding of the rising wall of a gasket at the time of shrinkage, and shrinking the opening section of a metal case to the outer diameter size of the barrel section of the case. CONSTITUTION:An insulating gasket 9 and a sealing cover body 10 are mounted on a step member 2 below the rising section 3 of a case 1. The rising wall 9a of the insulating gasket 9 is made thick near its upper section, and the outer periphery above the thick section is cut and made thin. It is pushed up into the cylinder hole 22 of a drawing die 23 to be shrunk, and the rising section 3 is folded inward near its upper end by a bumping die 26 to fix the sealing plate 11 of the sealing cover body 10. It is then pushed up into the cylinder bole 27 of the drawing die 28 to be shrunk until it is brought into contact with the lower face of a knockout 30. The outer diameter of the rising section 3 of the cylindrical case 1 is made equal to the outer diameter (phi1) of the case 1, and a shrunk section 15 formed at the opening end of the case 1 is further shrunk in diameter, and its inner diameter is made phi8. The circular bent section 14 of the cylindrical case 1 is further bent inward, and its inner diameter is made phi9.