Damper device and hood including damper

Claim 1

A VENTILATING HOOD HAVING A BLOWER FOR DRAWING AIR INTO THE HOOD AND DISCHARGING THE AIR THEREFROM THROUGH EITHER ROOF OR WALL DUCT WORK, SAID HOOD COMPRISING A CASING HAVING A TOP WALL AND A BACK WALL WITH AN AIR EXHAUST OPENING IN EACH OF SAID WALLS, A BLOWER HOUSING FASTENED TO THE CASING AND HAVING AN AIR INLET PORT AND WALLS DEFINING AN AIR EXHAUST PASSAGE LEADING FROM SAID INLET PORT TO BOTH SAID EXHAUST OPENINGS, A COVER FOR ONE OF SAID OPENINGS, A FRAME MEMBERS DEFINING A DAMPER PASSAGE THERETHROUGH AND HAVING A BEARING PORTION WITHIN SAID DAMPER PASSAGE, A DAMPER PLATE HAVING A BEARING PORTION, GUIDE MEANS MOUNTING AND SUPPORT SAID DAMPER PLATE THEREON IN SAID DAMPER PASSAGE WITH THE DAMPER PLATE BEARING PORTION OPPOSING THE FRAME BEARING PORTION FOR PIVOTING THE DAMPER PLATE BETWEEN A CLOSED POSITION BLOCKING SAID DAMPER PASSAGE AND AN OPEN POSITION UNBLOCKING SAID PASSAGE, SAID GUIDE SLIDING SAID DAMPER PLATE THEREON ADDITIONALLY FOR GUIDED SLIDING MOVEMENT OF SAID DAMPER PLATE AWAY FROM AND TOWARD SAID FRAME AT SAID BEARING PORTIONS, STOP PLATE MEANS ON SAID FRAME MEMBER ADJACENT SAID GUIDE MEANS AND PROJECTING INTO SAID DAMPER PASSAGE FOR STOPPING THE GUIDED SLIDING MOVEMENT OF SAID DAMPER PLATE ON SAID GUIDE MEANS AT A POSITION WITH SAID DAMPER PLATE IN CONTACT WITH SAID STOP PLATE MEANS AND WITH SAID DAMPER PLATE BEARING PORTION AWAY FROM SAID FRAME BEARING PORTION A DISTANCE INSUFFICIENT TO OPEN SAID DAMPER PASSAGE, SAID STOP MEANS BEING OF AN EXTENT BLOCKING FLOW AROUND SAID DAMPER PLATE WITH SAID DAMPER PLATE IN THE AWAY POSITION AND IN CONTACT WITH SAID STOP PLATE MEANS, ABUTMENT MEANS ON THE OPPOSITE SIDE OF SAID FRAME FROM SAID GUIDE MEANS IN SAID DAMPER PASSAGE OFFSET FROM SAID BEARING SURFACES FOR STOPPING THE PIVOTAL MOVEMENT OF SAID DAMPER PLATE AT SAID CLOSED POSITION WITH SAID DAMPER PLATE ASLANT, AND MEANS FOR RELEASABLY SECURING SAID FRAME AND COVER ACROSS EITHER OF SAID EXHAUST OPENINGS, SAID COVER AND FRAME BEING INTERCHANGEABLE ACROSS EACH OF SAID OPENINGS.