Exhaust coupling with an adjustable airway

A coupler for connecting a vehicle exhaust pipe to an exhaust extraction hose, said coupling including a housing (32,116) having an inlet end (34,124) adapted for connection to the exhaust pipe, an outlet end (36,118) adapted for connection to the extraction hose, and a curtain wall assembly (68,122) positioned adjacent the inlet end for sealing contact with an exhaust pipe when in use, characterized in that:

• said curtain wall assembly (68,122) comprises at least a pair of facially abutting flexible curtain wall members (70,126) defining a plurality of flexible, mutually offset, adjacent flap member (78,140), and a clamping ring member (80,128) peripherally clamping the curtain wall members (70,126) together;
• air passageway means (52,145) extend through said housing downstream of said curtain wall assembly, and an adjustable slider member (56,144) is provided on said housing, said slider member having air passage means (58,144) which can be moved into and out of registry with said air passageway means to increase or decrease airflow through the air passageway means.