Abstract: An environmental control system of a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system. A switching unit is used to selectively couple the inlet and outlet of an environmental control system to the upper and lower vents.

Abstract: A heating and cooling system for a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system.

Abstract: A retractable vent system includes extendable portions that can be extended or retraced to position an inlet or outlet end of the vent at different locations. The extendable portion may be manually movable or power operated.

Abstract: An environmental control system of a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system. A switching unit is used to selectively couple the inlet and outlet of an air handling unit to the upper and lower vents.

Abstract: A heating and cooling system for a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system.

Abstract: An environmental control system of a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system. A switching unit is used to selectively couple the inlet and outlet of an air handling unit to the upper and lower vents.

Abstract: An environmental control system of a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system. A switching unit is used to selectively couple the inlet and outlet of an environmental control system to the upper and lower vents.

Abstract: An environmental control system of a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system. A switching unit is used to selectively couple the inlet and outlet of an environmental control system to the upper and lower vents.

Abstract: A heating and cooling system for a building utilizes lower vents which open into lower portions of rooms of a building, and upper vents which open into upper portions of rooms of the building. When the system is operating in a heating mode, heated air is delivered into the upper portions of the rooms through the upper vents and air is removed from the rooms through the lower vents. When the system is operating in a cooling mode, cool air is delivered into the rooms through the lower vents, and air is removed from the rooms through the upper vents. Operating the heating and cooling modes in this fashion provides the most efficient operation of the heating and cooling system.

Abstract: A safety device for a power saw, such as a miter saw, includes an interference stop mounted on the frame or other support of the saw. The stop prevents a lower pivotal blade guard of the saw from being pushed away from a covering relationship with respect to the saw blade when the saw is moved from a "cutting" position to a fully raised "home" position, thereby preventing accidental exposure of the saw blade.

Abstract: Supplemental guards are pivotally mounted on opposite sides of a conventional saw blade housing associated with miter saws. The supplemental blade guards are mounted so as to normally extend outwardly beyond the cutting blade whenever a miter saw blade is not engaged with a workpiece. The supplemental guards are positively guided as they are pivoted relative to the saw blade by contact with a workpiece as the miter saw blade is lowered to a cutting position.

Abstract: A radial arm saw is provided with pairs of outside and inside lower blade guards which normally extend outwardly beyond the cutting blade of the saw. The lower blade guards are normally locked in covering relationship relative to the saw blade unless released by the operation of a safety lock assembly including a pair of pivotable stop members which are engageable with the lower blade guards. The safety lock assembly includes a handle for pivoting and releasing the stop members when the radial arm saw is used in a crosscutting mode and a separate release rod which extends from the forward end of the saw assembly to the rear end thereof and which is operable to release the stop members when the saw is utilized in a rip cut mode.