Variable speed damper means

Automatic damper means having damper blades rotatably mounted in an adjustable housing, said blades being rotatable between open and closed positions by electrically energized motor means and attaching rotating means; interchangeability of said rotating means connecting to damper blades provide for a variation in the rpm's of said damper blades.

In central heating/cooling installations having rotating damper blades 
controlling a heating/cooling medium flowing through ducts, the velocity 
of the medium and the angular velocity (rpm's) of the damper blades 
sometimes cooperate to produce undesirable sounds as the blades 
immediately leave or approach a closed position whenever the medium is 
flowing through said ducts. 
The present invention provides damper means whereby the rpm's of the damper 
blades may be changed to satisfy the user's requirement for sound 
reduction. 
The subject invention incorporates multiple damper blades rotatably mounted 
in an adjustable housing. Each blade is supported within the housing by 
means of bearing pins attached to the blades and rotates in holes formed 
in end panels of said housing. An electrically operated motor having its 
shaft attaching to a first gear rotates a second gear meshing with said 
first gear. As the second gear rotates under the influence of the first 
gear, a cam, having a shaft securing said second gear and a switch 
operator, influences one of said multiple blades to move with said cam 
into an open position. Linkage means interconnecting cam following blade 
to other blades urge all blades to an open or closed position depending on 
movement of the blade following said cam; said blades being in a fully 
open position when they are vertical. 
As the cam rotates to close the blades, a torsion spring provides a 
restoring force that returns blades to the closed position, and limit 
switches, activated by switch operators, energize and deenergize motor 
means at the open and closed positions of said blades. The rpm's at which 
the damper blades rotate are established by the ratio between the first 
and second gear diameters. 
The rpm's of the blades can also be varied when a first or primary timing 
pulley is secured to the shaft of motor means and secondary timing 
pulleys, having equal diameters with each other but different from said 
first timing pulley, connect to said damper blades, the rpm's of the 
damper blades being directly related to the diameter ratio of primary and 
secondary pulleys. 
A third and more direct method of varying blade rpm's is the use of motors 
having different speeds, and having aforesaid cam attaching directly to 
the shaft of the motor means. The rpm's of the blades will be equal to the 
rotational velocity of the motor shaft. 
It is the primary purpose of the invention to provide motor operated damper 
means that permit the rpm's of the damper blades to be varied in 
accordance with the requirements of the user.

Making reference to the particular drawing Figures, FIG. 1 shows an 
automatically operated damper means 10 having damper housing 11 formed of 
side panels 12 and 13, end panels 14 and 15, and an interior panel 16. As 
shown in FIG. 11, said damper housing is adjustably supported by bracket 
56 having slotted opening 57 capable of moving vertically along an axis 
containing fasteners 58. The horizontal leg of bracket 56 is constructed 
to be supported on means external to said damper means, such as floor, 
wall, or ceiling members when vertical leg of said bracket is secured to 
panels of damper housing 11 by fasteners 58 (FIGS. 5 and 6). 
The top and bottom sections of the damper housing are open, but a series of 
intermediate damper blades 17 open and close to control and regulate the 
flow of a heating/cooling medium passing through said damper housing 11. 
Damper blades 17a and 17b, representative of the multiplicity of blades 
that can be mounted in the damper housing, have bearing pins 26 mounted on 
off-center axes of said damper blades and are rotatably supported in holes 
in end panel 14 and intermediate panel 16. Motor means 18 is mounted on 
end panel 15 by fasteners 19. The shaft 18a (FIG. 2) captures gear 20b, 
said gear 20b meshing with gear 20a which attaches to shaft 25a of damper 
operating cam 25. As shown in FIGS. 1, 5, and 6, damper blade 17b rests on 
a ledge of cam 25, and on resilient means 9 bonding to housing panels, 
when blades are in a closed position. As cam 25 rotates counterclockwise, 
blade 17b is moved to the vertical or open position by the leading edge of 
said cam. Linkage means 28, being comprised of a connector bar 28a and 
plates 28b and 28c interconnect blade 17a to 17b forcing blade 17a to 
rotate with cam follower blade 17b. 
The preceding rotation of damper blades occurs when thermostatic means 35 
of FIG. 7 requests that the temperature of the controlled environment be 
increased from that of the present status. Accordingly, switch lever 35a 
of thermostatic means 35 moves to position 35b-35d, energizing light means 
34, relay coil 33 and solenoid 30 of fuel control means 29. 
Simultaneously, motor means 18 is energized through switch lever 21a 
(dashed position) and contacts 31 (said contacts were closed when relay 
coil 33 was energized). The resulting rotation of motor means 18 
culminates in the opening of said damper blades 17 by cam 25. During the 
described operation simultaneous functions were performed by the switch 
operating cams 22 and 24 attached to motor shaft 18a and bearing pin 26a 
respectively. 
As motor means 18 was energized, switch operating cam 22 (FIG. 2) engaged 
motor switch 21 maintaining it in a closed position for continuous 
energization of motor means 18 during the present cycle. In like manner, 
switch operating cam 24 engaged hold-in switch 23 to maintain an auxillary 
closed circuit between thermostatic means 35 and motor means 18 should 
switch lever 35a inadvertently be moved to position 35b-35e while switch 
lever 21a was being held in position 21c-21d by switch operating cam 22. 
Hold-in switch 23 continued to provide a closed circuit for motor means 18 
until damper blades are rotated to the position consistent with the 
operational status of the heating/cooling device. Damper blades 17 remain 
in an open position during the time thermostatic switch lever 35a is 
energizing fuel control means 29. 
Upon reaching the desired temperature, thermostatic switch lever 35a moves 
to the dashed position, releasing control over relay means 33, fuel 
control means 35, light means 34, and reenergizes motor means 18; switch 
lever 21a being in position 21c-21d. As motor shaft 18a rotates damper 
operating cam 25 counterclockwise, torsion spring 27 (FIG. 6) influences 
damper blade 17b to follow said damper operating cam 25; said blade 17b 
riding along the curvature of cam 25 until damper means are in a closed 
position. During this cycle, switch operating cam 22 does not contact 
switch 21 thereby leaving switch lever 21a (FIG. 7) in position 21c-21d, 
compatible with position 35c-35e for thermostatic switch lever 35a. 
However, the hold-in switch 23 is again maintained in a closed position as 
switch operating cam 24 rotates in a clockwise direction with damper blade 
17b. 
In FIG. 7 it can be observed that relay means 33 and fuel control means 29 
are subject to control by a multiplicity of thermostats connecting to 
conductor 40; thermostatic means 35 being representative of other 
thermostats downstream. Thus, whenever current is flowing in conductor 40, 
the relay means will be energized and normally open contacts 31 will be 
closed allowing motor means 18 to rotate when required. However, when 
thermostatic means 35 are the last means of all thermostats to go off 
line, relay coil is deenergized and contacts 31 opened when switch lever 
35a moves to position 35b-35e; hi-temperature switch 32 mounted in a hot 
zone of the heating/cooling device remains in an open position thereby 
preventing motor means 18 from being energized to close damper blades 17. 
This delay in closing said damper blades allows residual conditioned air 
in the heating/cooling device to be transported into the room. As said 
heating/cooling device cools, hi-temperature switch 32 closes, completing 
the previously open circuit of the motor means, and motor means 18 rotate 
damper blades 17 to the closed position shown in FIG. 5. 
When conditions require that all thermostatic means be disengaged from the 
fuel control means 29, manual switch 38 provides a central on-off station. 
A second manually operated switch 36, having light means 37 provides for 
manual operation of motor means 18 independently of thermostatic means 35; 
said light means 37 communicating the open/close position of said damper 
blades 17. 
Based on the foregoing description of the operation of the damper means and 
the spatial relationship of gear means 20 shown in FIG. 2, it can be seen 
that a change in the diametric ratio of gears 20a and 20b will change the 
rpm's of said damper blades 17. 
An alternate means for varying the rpm's of the damper blades incorporates 
the transmission means shown in FIGS. 8-10. Where component numbers shown 
in these Figures are identical to previously used numbers, it indicates 
that said components are also identical in both cases. 
FIG. 8 shows the damper means having a multiplicity of damper blades 
17a-17c rotatably supported by bearing pins 26a-f. Each of said bearing 
pins extending through intermediate panel 16 captures a timing pulley 51 
through 53, said pulleys being partially encircled by belt 54. Continuous 
belt 54 also partially encircles drive pulley 50, said drive pulley 
attaching to motor means 18. 
Bearing pins 26a and 26c have attaching switch operating cams 24 and 22 for 
operation of motor switch 21 and hold-in switch 23 respectively as 
heretofore explained. 
Referring to FIG. 7, when switch lever 35a of thermostatic means 35 moves 
to position 35b-35c and motor means 18 are energized to open damper blades 
17, motor shaft 18a rotates pulley 50 through an arc sufficient to rotate 
pulleys 51-53 through an angle of 90 degrees, whereupon switch operating 
cams 22 and 24 disengage said switches to deenergize motor means. Upon 
being satisfied thermostatic means 35 moves switch lever 35a to position 
35b-35e and motor means, being again energized by switch lever 21a 
presently in position 21c-21d, rotates pulley 50 until pulleys 51-53 have 
rotated 90 degrees and closed damper blades 17, whereupon switch operating 
cam 22 and 24 deenergize motor means as previously stated. Belt 54 serving 
to transmit rotation from pulley 50 to pulleys 51-53 is maintained in a 
tensile condition by belt tensioners 55 having rotating sleeves 55a to 
reduce friction on said belt as said belt 54 passes over said sleeves. 
As with the gear means in FIG. 2, the rpm's of the damper blades can be 
altered by changing the diametric ratio of pulley 50 versus pulleys 51-53. 
When independent means are utilized to determine the most favorable rpm's 
for a given system of blades, motor means 18 can be selected from a rather 
wide range of timing motors having specified rpm's; and shaft 18a (FIG. 3) 
can be connected directly to damper operating cam 25 via opening 25b. As 
cam 25 operates damper blades 17 as previously described, all other 
functions, including operation of torsion spring 27 (FIGS. 6 and 7), 
switch operating cams 22 and 24, and switches 21 and 23, are performed in 
the same manner described for the operation of the motor means having gear 
means rotating said damper operating cam 25. 
As shown typically in FIGS. 4, 9, and 11 all housing means incorporate 
motor covering means 59 for sealing off motor compartment and protecting 
motor means. 
Thus, there has been shown and described a novel automatic damper means 
which fulfills all of the objectives and advantages sought after. Many 
changes, modifications, variations and other uses and applications of the 
present device will, however, become apparent to those skilled in the art 
after considering this specification and accompanying drawings. All such 
changes, modifications, variations, and other uses and applications which 
do not depart from the spirit and scope of the invention are deemed to be 
covered by the invention which is limited only by the claims which follow: