PURPOSE: To facilitate installation and removal of a cover and taking out and carrying in of circuit boards, etc., in a duct by installing control circuit boards, etc., in a case of the duct and engaging the cover in a specific state with the case.
CONSTITUTION: A cover 22 of a duct is divided into moderate dimensions capable of readily performing installation and removal. Each circuit board 5 is supported on a case 21 with a board supporting tool 24 and a groove 33. Grooves 31 and 32 of the case are engaged with protruding parts 41 and 42 of the cover. The cover is made of a resin material having a moderate elasticity for bending. The cover is bent while holding a semicircular groove 43 with the thumb and a recessed part 44 with the residual fingers so as to lift the case. Thereby, engagement of the groove 32 with the protruding part 42 is released.
CHIBA HIROSHI
KURITA MASANORI
