Abstract: Attaching structure to secure a fire damper in proper position in a fluid passage in a fire wall comprising an elongated bendable strap of sheet material secured to the damper frame on each side of the damper. The frame is inserted in the passage by the installing workmen and the projecting legs are then bent from their initial positions lying flat against the exterior surface of the damper frame and into embracing relationship with the building studs defining the passage opening. The bent legs of the strap securely anchor the damper in position against forces applied to the damper.

Abstract: A fire damper with mounting structure which permits the dampers easy installation in a building ventilation duct or passage without the use of conventional, external flanges which must be bolted on at the installation site. The damper includes a peripheral frame having internally threaded, tubular elements secured to the inside of the frame and aligned with apertures extending through the frame. Threaded studs in the elements have self-boring, conical noses so that the studs may be advanced into gripping engagement with the proximal building wall.

Abstract: A one-piece damper frame wherein transverse slots in a channel shaped longitudinal frame member permit the frame sections to be bent to define a frame opening and flanges integral with the channel are unsevered to provide continuous integrity throughout the frame perimeter. Tabs formed in the frame material by extensions of the transverse slots overlap the proximal frame section across the corner and are secured in a manner to rigidly hold the corners in their appropriate angled positions.

Abstract: A fire and smoke damper having an electric motor coupled with the damper to hold the damper blades open when the motor is energized. A spring associated with the motor provides torque for closing the blades when the supply of electrical energy to the motor is interrupted. A thermal responsive electrical switch is mounted on the damper and incorporated in the electric circuit which supplies energy to the motor so that the motor is de-energized and the damper is closed when the ambient temperature reaches a predetermined level.

Abstract: A damper assembly is provided which comprises a duct having an opening and a blade movable between a closed position in covering relation to a portion of the opening and an open position. A fusible retainer holds the blade in its open position and releases the blade when the retainer is sufficiently heated. When released, the blade is urged to its closed position by a hinge member which connects the blade to the duct. The blade in its closed position cooperates with the hinge member to substantially prevent flow of fluid through the opening.

Abstract: A vacuum relief and access door assembly, for use on a duct downstream of a fire or control dampers, comprises a frame including a duct facing surface with a seal member thereon, a closure member having side edges in sealing engagement with the seal member, and cooperative retaining members mounted on the frame and closure member and resiliently urging the closure member into sealing engagement with the seal member, yielding to allow the closure member to displace toward the duct to allow air flow thereby for vacuum relief and returning into sealing engagement with the seal member said retaining members being releasable for removal of said closure member.

Abstract: A vacuum relief and access door assembly, for use on a duct downstream of a fire or control dampers, comprises a frame including a duct facing surface with a seal member thereon, a closure member having side edges in sealing engagement with the seal member, and removable retaining members mounted on the frame and resiliently urging the closure member into sealing engagement with the seal member, yielding to allow the closure member to displace toward the duct to allow air flow thereby for vacuum relief and returning into sealing engagement with the seal member.

Abstract: A control damper is mounted in a building duct system for closing a control opening through a housing or frame and includes a linkage connected to the housing and to a vane positioned in the control opening and is operative for moving the vane between a flow permitting position and a position closing the control opening. The linkage includes a fusible portion permitting a resilient member to move the vane to the position closing the control opening in the event of temperature above the melting point of the fusible portion. Cooperating latch members are mounted on the housing and on the vane and are moved into vane holding engagement after melting of a fusible portion and movement of the vane to the position closing the control opening through the housing.

Abstract: A folding blade damper comprising a rectangular frame and an assembly of blades hingedly interconnected along longitudinal marginal edges by tubular hinge elements. A spring is interposed between each interconnected pair of blades to resiliently urge the blades from a folded to an unfolded flow blocking position across the frame. The spring comprises a flat member having an arcuate portion generally coaxially of the tubular hinge elements and oppositely extending arms in overlying engagement with adjacent blades with fingers extending over an edge of a respective blade to engage the opposite face thereof and cooperate with the arms to resiliently and removably secure the spring to said blades whereby the arcuate portion is contracted upon folding of said pair of blades and then exerts a torque urging the connected blades to unfolded position.

Abstract: A control damper is mounted in a building duct system for closing a control opening through a housing or frame and includes a linkage connected to the housing and to a vane positioned in the control opening and is operative for moving the vane between a flow permitting position and a position closing the control opening. The linkage includes a fusible portion permitting a resilient member to move the vane to the position closing the control opening in the event of temperature above the melting point of the fusible portion. Cooperating latch members are mounted on the housing and on the vane and are moved into vane holding engagement after melting of a fusible portion and movement of the vane to the position closing the control opening through the housing.