Damper construction

Abstract

A damper controls fluid flow and includes a frame with an opening through which the fluid is intended to flow when the damper is open, and a closure cap movable between a first position in which it blocks the opening and a second position in which the opening is unblocked. In the second position, the closure cap is rotated with respect to its first position, so as to minimize interference with fluid flow through the opening. A mechanism controls the movement of the closure cap, and includes a first and second bracket fixed with respect to the frame and the closure cap, respectively. An elongate guideway is defined in one bracket and a pin on the other bracket is captive within the elongate guideway. The brackets include a stabilizing track arrangement spaced from the guideway and the pin, and being such as to require the second bracket to substantially retain a given angular orientation with respect to the first bracket while the pin slides from a first end to a second end of the elongate guideway, thus moving the closure cap in translation with respect to the frame, and to rotate with respect to the first bracket about the second end of the elongate guideway, thus moving the closure cap in rotation with respect to the frame. A cylinder or the like is provided to positively move the brackets with respect to each other.