| 摘要 |
PURPOSE:To provide a filter case without producing clearance and small holes in a caulking part due to loosening, and mass-produce it at a low cost by permitting a small projection on a second side plate to penetrate a small hole formed in a bent part of a first side plate and collapsing and flattening a head of said small projection. CONSTITUTION:A first side plate part 4 has a bent part 9 overlapped on a second side plate part 5 adjoining thereto, which bent part includes a small hole 10 therethrough. In addition, a small projection 12 is embossed on the second side plate part 5. After the small projection 12 is allowed to penetrate the small hole 10, a movable guide cylindrical part d of a die D is projected and inserted into the small projection 12, and a punch P2 is lowered, whereby a head part of the small projection 12 is collapsed and flattened. Bonding by such caulking is applied likewise between the first side plate part 4 and a fourth side plate 7 as well as among a third side plate part 6, the second side plate part 5, and the fourth side plate part 7. |
