Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
It is well known that open chimney flues present
opening for unwanted a~mission of rain, insects, animals, and
birds to homes or other buildings. Further it is well known
that significant heat loss occurs through open chimney flues
during the winter when a damper or other means is not provided
to close off the chimney opening when there is no fire in the
associated fireplace.
Various means have been provided for closing a
chimney or flue when not in use such as the well known fire
box damper, and various other prior arrangements. Some such
prior arrangements are illustrated in U.S. 2,704,502, Rainey,
and U.S. 2,856,839, Soderberg, as well as U.S. 3,267,832,
Hinkle.
Such prior arrangements have certain disadvantages
and it is an object of the present invention to overcome many
of the difficulties encountered in the use of the prior art
arrangements.
Specifically, such previous arrangements have per-
mitted wind blown rain to enter the chimney even though the
damper located at the top of the chimney is closed. Moreover
in most such arrangements it has been provided for the damper
to be normally closed so that when the means to secure the
damper are not functioning the damper is in a closed position
and if a fire is built in the fireplace, when the damper is
closed, the associated rooms are filled with smoke.
In an arrangement shown in U.S. Patent 3,945,307,
Lyemance, a normally open damper arrangement is shown to in-
clude a sealing arrangement to prevent leakage of rain or snow
into the chimney which further provides a seal to reduce heat
loss from the chimney. It has been found that such normally
open dampers, which provide safety features that the damper
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normally -Eails to open freezing rain and snow, under severe
conditions prevent opening of the damper.
The present invention provides a damper arrangement
to be received by the top of a chimney where a generally rec-
tangular frame is provided defining an opening from the chimney
with a damper flap which is pivotably mounted on the frame.
Devices in accordance with the present invention prevent wind
blown rain from entering the chimney flue and likewise provides
straight forward inexpensive damper arrangements where the
damper flap is pivotably mounted on the frame member to be
retained in a normally opened position so that in the event of
failure of the means provided to close the damper flap, or upon
release of the retaining means the damper flap moves to an open
position and also provide means to open the damper flap when
it is forzen closed during cold weather and does not pivot to
open position when the associated retaining device is reclosed.
Briefly, the present invention provides a naw and use-
ful safety arrangement for use in a pivotable chimney damper to
selectively open and close the outlet from the flue of a chimney
where the damper includes an open frame of substantially rec-
tangular shape to be received on the top of the chimney defining
an outlet opening from the chimney flue where a damper flap is
cooperatively and pivotably carried by the frame where the flap
: is formed with a periphery substantially identical to the peri-
phery of the frame to engage the frame when the damper is pivoted
to the closed position, to prevent air and water from flowing
into the chimney. The damper flap is advantageously pivoted to
and includes bias means to urge the damper flap to a normally
open position with respect to the frame when unrestrained and
carries closure means, which can include flexible pull means to
be attached at a first location to the damper flap to pull the
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damper flap to a closed position against the frame mer~her when
the pull means is drawn taught where the pull means can be
secured ko hold the damper in closed position. An expansible
spring means is attached between the damper flap and the pull
means to be pulled to extended position when the damper flap is
closed. In accordance with the present invention a flexible
connector is joined to the pull rneans at a locatian below the
spring means and the damper flap at a second location where
pulling the connector urges the damper toward open position
where the length of the flexible connector is such that upon
selected extension of the spring means the flexible connector
becomes taught and the for¢e exerted on the second location is
in excess of the force exerted on the first location so the
damper flap is urged toward open position.
The invention is illustrated by way of example in the
accompanying drawings wherein:
FIGURE 1 shows a perspective view partly in section
of one example of a damper in accordance with the present
invention as described hereinafter.
FIGURE~ 2A-2B, present a schematic illustration of
operation of the arrangement shown in Figure 1.
The example of the present invention shown in
Figure 1, includes a generally rectangular frame member 1 which
is provided to rest on the top at the outlet of the flue of a
chimney (not shown) in which the damper arrangement is installed.
A depending flange 2 can be provided to extend downwardly from
frame 1 over the outer surface of the chimney flue, Frame 1
likewise includes an upstanding generally rectangular flange
provided with an inverted channel mernber 6 at the top edge
thereof, which extends partially around the periphery of flange
4 as shown. A sleeve 3 can be provided, as shown, to extend
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downwardly into the flue liner adjacent the wallsof the chimney.
As shown, damper flap 7 is provided to be pivotably
mounted in cooperation with flange 4 for example by means of a
pivot 9. Pivot 9 is advantageously journaled, for example in
flange 7 so that when damper flap 7 is unrestrained, the damper
flap is rotatable in a clockwise direction out of engagement
with channel 6 to open generally vertical position exposing the
opening defined by flange 4 and opening the chimney flue, a
weight 17 can be provided to provide additional force tending
to open flap 7.
As shown, damper flap 7 includes a downwardly extend
ing lip 5 which can, advantageously extend substantially around
a portion of damper flap 7 which extends beyond the limits of
flange 4. An upstanding flange 8 is provided around a portion
of the periphery of flap 7 to be received in channel 6 to pro-
vide a seal between flange 4 and damper 7 extending substantially
around flange 4 and the periphery of damper 1 from one end of
pivot 9 to the other.
A bracket 12 can be provided on the underside of flap
7 to be connected to a flexible damper pull means, for example
a chain 11 by means of an expansible spring 13. Chain 11 ex-
tends downwardly through the chimney to fireplace associated
with the chim~ey for closing damper 7 and can be retained
therein to hold damper 7 in closed position by latch means (not
shown).
Spring 13 is provided to provide a selected tension
when chain 11 i9 pulled after damper 7 is closed, to provide
additional bias to hold damper 7 in a closed position and
securely fasten damper 7 in sealing relation with flange 4,
when chain 11 is pulled to extend spring 13,
Additionally, in accordance with one feature of the
present invention, spring 13 also provides means, as described
hereinafter to alleviate the force components on damper 7 to
release damper 7 where damper flap 7 is frozen or stuck closed.
In accordance with another feature of the present
invention a sealing compound 14 can be provided on the under- -
side of frame 1 between flange 2 and sleeve 3 to seal the under-
side of flange 1 to the top of the chimney to which the apparatus
is placed, In the alternative,bolts (not shown) can be provided
to extend through cooperative openings in sleeve 3 and fastened
to the chimney flue to secure the damper arrangement in place.
In operation, frame 1 is received on the chimney to
which the damper arrangement to be installed, with flanges 2
extending downwardly along the outer surface of the chimney
while a sleeve 3 is received by the flue defined within the
chimney,
The normally open characteristic can be achieved by
locating pivot 9 off center so that the portion 7A of damper
flap 7 opposite bracket 12 in portion 7B of damper flap 7 is
heavier so that flap 7 pivots about pivot 9, when unrestrained
to fall to the open position. If faster or more certain action
is desired, a weight 17 can be added to portion 7B of flap 7
to accentuate the off-center character of pivot 9.
Damper flap 7 as previously-described is normally open~
As previously discussed, damper flap 7 is closed by pulling
connector 11 and fastening to suitable fastener means and which
is located with:in the fire box in the fireplace (not shown).
As further previously described, connector 11 can then
be pulled further to extend spring 13 to provide a resultant
force urging damper flap 7 into closed position.
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Upon release of chain 11 damper flap 7 is then rotated
by gravitational force, resulting from the location of pivot 9
to an open position extending generally vertically into coll~r
3 and the chimney flue so that the flue is open and ready for
use. It will be noted that in the event spring 11 breaks, damper
flap 7 will always "fail safe" by rotating to an open position
so that the chimney is available for use. In arrangements
where the damper is opened by pulling a chain or similar meansJ
considerable difficulty is experienced when the chain breaks
so the damper return to normally closed position. Extreme
difficulties arise when the opening means break after a fire
is already set in the associated fireplace.
In the event water accumulates on the upper surface
of flange 7 and freezes damper flap closed, or if accumulation
of foreign materialaround the edge of dampér flap 7 which causes
the damper to stick,chain 11 can be drawn to extend spring 13.
In accordance with one feature of the present inven-
tion, as illustrated in Figure 2B, when damper flap 21 is stuck
closed so that it does not open by gravity chain 27 is pulled
to extend spring 24, so connector 23 is pulled taught and the
point of application of force by chain 27 moves in and are
determined by the length of connector 23 toward an area beneath
the center of damper 21 and the portion of the force exerted by
chain 27 on connector 23 increases while the force component in
spring 24 decreases to the point where the force on connector
23 exceeds that on spring 24 and damper 21 is pulled open.
