Ventilation – Chimney or stack – Chimneytop or stacktop structure
Reexamination Certificate
1999-07-30
2001-03-27
Joyce, Harold (Department: 3749)
Ventilation
Chimney or stack
Chimneytop or stacktop structure
C454S030000, C454S359000
Reexamination Certificate
active
06206774
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to devices for ventilating building structures, and in particular, to roof mounted, environmental exhaust ducts, i.e. dryer, bathroom, kitchen, range, microwave oven, grill, etc. In particular, the invention relates to environmental moisture-exhaust ducts for assembly with dryer vent hoses commonly used for venting household clothes dryers.
2. Description of the Related Art
Many types and designs of exhaust ducts are known, some of which are specifically designed for venting clothes dryers. Conventional dryer vents have a short tubular section which is installed through an outside wall so that when connected to the dryer vent hose, the exhaust air is expelled outside the house. Various designs of dryer vents are known.
U.S. Pat. No. 2,754,748 (Daggett), U.S. Pat. No. 3,285,155 (Maltenfort) and U.S. Pat. No. 4,151,789 (Grobard) disclose various dryer vents specifically designed for installation in a building wall. U.S. Pat. No. 5,711,091 to Bos discloses a dryer vent specifically designed for mounting in a soffit. U.S. Pat. No. 5,632,678 to Doelfel discloses a roof dryer vent with a downwardly facing air outlet, and a removable lint screen attached to the outlet. Various roof exhaust vents are known, each with some type of cover, and a hinged flap over the air shaft. U.S. Pat. No. 2,741,972 (Pryne), U.S. Pat. No. 3,250,206 (Strouth) and U.S. Pat. No. 5,344,464 (Pollock) disclose roof vents in which the rear wall extends over the air shaft in a dome-like structure to act as a cover. U.S. Pat. No. 5,662,522 to Waltz discloses an exhaust vent suitable for installation in either a roof or wall. The vent of Waltz is complicated and requires many parts, and has a horizontal outside opening to the air shaft.
None of the prior art devices provide a simple, easily manufactured device which allows for ventilating gases through a building roof without obstructing the air flow. It is an object of the instant invention to provide such a roof environmental exhaust duct.
SUMMARY OF THE INVENTION
The roof environmental exhaust duct of the instant invention is designed to allow exhaust gases to be vented through a building roof without obstructing the air flow, eliminating potential lint build-up while preventing rain, snow, birds, rodents, insects and debris from entering the duct. The roof environmental exhaust duct of the invention does not require maintenance or filter cleaning or replacement. In accordance with an embodiment of the instant invention, the roof environmental exhaust duct comprises a hollow tubular member having first and second open ends. The first end is adapted to be inserted into the opening in the roof from the outside and to extend through the opening for delivering exhaust gases from the building to the outside atmosphere. The second end has a smoothly sloping edge extending from a low point arbitrarily designated as the front of the tubular member to a high point arbitrarily designated as the back of the tubular member. First and second vertical support members extend upwards from the sloping edge with free ends remote from the sloping edge. The vertical support members, which may be integral with the tubular member, or distinct parts affixed to the tubular member, are symmetrically disposed about the high point of the sloping edge. A flap is pivotally mounted to the sloping edge of the back of the tubular member between the first and second vertical members such that the flap is gravity biased to close the open second end of the tubular member, wherein the flap is slightly larger than the open second end of the tubular member to prevent the flap from entering the tubular member in the closed position. The flap acts as a back-draft damper to prevent water, birds, rodents, insects and debris from entering the air shaft without the requirement for a screen. A conical cap is attached to the free ends of the vertical supports and spaced apart from the flap to allow the flap to be pushed up by exhaust gases, and the cap extends horizontally beyond the tubular member to prevent water and debris from entering the building through the tubular member.
REFERENCES:
patent: 764965 (1904-07-01), Tousley
patent: 1053508 (1913-02-01), Hiett
patent: 1725971 (1929-08-01), Zacharias
patent: 2060231 (1936-11-01), Malone et al.
patent: 2695554 (1954-11-01), Jenson et al.
patent: 2741972 (1956-04-01), Pryne
patent: 2754748 (1956-07-01), Daggett
patent: 2923225 (1960-02-01), Massey
patent: 3085490 (1963-04-01), Field
patent: 3250206 (1966-05-01), Strouth
patent: 3270656 (1966-09-01), Cood
patent: 3285155 (1966-11-01), Maltenfort
patent: 3324784 (1967-06-01), Lambie et al.
patent: 3472150 (1969-10-01), Strawsine
patent: 3785271 (1974-01-01), Joy
patent: 4151789 (1979-05-01), Grobard
patent: 4546919 (1985-10-01), Wells
patent: 5344363 (1994-09-01), Pollock
patent: 5632678 (1997-05-01), Doelfel
patent: 5662522 (1997-09-01), Waltz
patent: 5711091 (1998-01-01), Bos
Dexter Jim
Weinman Richard
Joyce Harold
Oppendahl & Larson LLP
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