US 4,241,748 A · Butterfly smoke/fire damper

Abstract

A pair of butterfly smoke/fire dampers are mounted on a single frame. Each damper includes a pair of blades which can be locked in the open position and which, when released, rotate about a hinge to the closed position. The frame has a flange around the inner periphery thereof which engages the edges of the blades in the closed position. Each pair of blades are moved to the open position by an operator cable which extends through a first ferrule in the frame, through a second ferrule in one of the blades and thereafter across the blades to a point of attachment complementally located on the opposing blade. The frame ferrule is offset from the blade ferrule whereby withdrawing the cable causes both blades to be drawn toward each other. The blades can be held in the open position by maintaining tension on the operator cable or by a fusible link or other heat responsive latching mechanisms.

Claims19

Dependent claims

A smoke/fire control damper for use in a duct, said damper comprising:

a. a frame adapted for mating with an opening of said duct;
b. a cross bar extending across said frame;
c. at least two substantially planar damper blades which engage said cross bar for pivotal displacement about said cross bar between open and closed positions;
and
d. operating means for pivoting said blades between the open and closed positions, said operating means comprising:
(i) a first operator cable guide means disposed in said frame;
(ii) a second operator cable guide means attached to a first one of said damper blades in a location which is offset from said first operator cable guide means;
(iii) an operator cable slidingly engaging said first and second operator cable guide means, one end of said operator cable being attached to an attachment point on a second one of said blades, said attachment point located substantially opposite said second operator cable guide means when said blades are in the open position;
and
(iv) means for exerting tension on said operator cable.

7 more elements

A smoke/fire control damper for use in a duct, said damper including a frame adapted for mating with an opening of said duct, said frame including a wall portion having a flange inwardly depending therefrom, said flange separating said damper into a first damper portion and a second damper portion, each damper portion comprising:

a. a cross bar extending across said frame;
b. at least two substantially planar damper blades which engage said cross bar for pivotal displacement about said cross bar between open and closed positions;
and
c. operating means for pivoting said blades between the open and closed position, said operating means comprising:
(i) a first operator cable guide means disposed in said frame;
(ii) a second operator cable guide means attached to a first one of said damper blades in a location which is offset from said first operator cable guide means;
(iii) an operator cable slidingly engaging said first and second operator cable guide means, one end of said operator cable being attached to an attachment point on a second one of a said blades, said attachment point located substantially opposite said second operator cable guide means when said blades are in the open position;
and
(iv) means for exerting tension on said operator cable.

6 more elements

Dependencies are inferred from the claim text.

Butterfly smoke/fire damper

Life of this patent

Butterfly smoke/fire damper

Life of this patent

Abstract

Claims19