CONNECTION DEVICE FOR CONNECTING TWO FLAT PARTS TOGETHER WITHOUT AIR LEAKAGE

Connection device (10) for connecting two flat parts (2, 3) of plastic material together, the parts comprising a first wall (4) and a second wall (5), respectively, which, in an assembled condition of the two parts (2, 3), are arranged one against the other. A through opening (11) is formed through the first wall (4) and a first collar formation (12) protrudes from the first wall (4). A second collar formation (13) protrudes from the second wall (5), a flat closure portion (14) is connected to the second wall (5) through the second collar formation (13), a third collar formation (15) protrudes from the closure portion (14), and a clip (16) is formed on the third collar formation (15). The clip (16) snap-fits with a coupling seat (18) formed in the through opening (11), and the first collar formation (12) of the first wall (4) fits between the second collar formation (13) and the third collar formation (15) so as to define a labyrinth passage.