The invention pertains to the art of flue or vent damper construction.
As a result of the desirability of energy conservation, a number of different types of flue or vent dampers have recently become available. Of the types with which we are familiar, all except the thermally actuated, bimetal type, have some kind of actuating means external of the flue pipe. If the external actuating means must be removed for any reason, such as service or replacement for example, the damper plate in the damper assemblies of which we know are generally free to assume any position between open and closed. That is, it is the external actuator which imposes control of the damper plate position and in the absence of the actuator there is no automatic control of the damper position. This can lead to a potentially unsafe condition in the event steps are not taken to insure that the damper is moved to an open position and then somehow fastened in that position if the actuator is to be detached for any significant period. An example would be if a replacement actuator was required during a service call, but the serviceman did not have one available in his mobile stock and had to leave the premises for some undetermined time during which it would be desirable that the furnace operate.
Accordingly, one aim of our invention is to insure that the damper plate automatically assumes an open position when the actuator is detached for any reason.
Another aim is to provide an arrangement in which biasing means associated with the damper plate shaft will automatically hold the damper plate and associated parts in the right position to facilitate coupling of the particular actuator means with the remainder of the damper assembly.