Diffuser unit for air conditioning system

A diffuser unit for air conditioning systems includes an air supply duct having an air inlet and two air outlets, two dampers for adjusting the open area of the respective air outlets, and a linkage mechanism interconnecting the dampers and a drive unit. The dampers include arcuate end portions for contacting an inner wall of the duct and for preventing the generation of wind noise from air being supplied through the duck. The linkage mechanism is so constructed as to displace a selected one of the dampers while holding the other damper in its closed position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a diffuser unit for air conditioning 
systems adapted to be mounted on the sidewall or ceiling of a house or 
building, a vehicle or the like. 
2. Prior Art 
A diffuser unit of this type is disclosed in Japanese Utility Model 
Laid-open Publication No. 60-34009. The disclosed diffuser unit includes 
an air supply duct having two air outlets adapted to be selectively opened 
and closed by a single damper disposed in the duct. When one of the air 
outlets is closed by the damper, the temperature controlled air is 
supplied solely from the other air outlet. When the damper is turned to an 
intermediate position, the air is blown-off from both air outlets. In this 
instance, the ratio of the flow rate of blown-off air from the one air 
outlet to the flow rate of blown-off air from the other air outlet is 
proportional to the angular position of the damper. 
In an application in which the diffuser unit is mounted on the ceiling of a 
house or building, it is highly desirable that one of the air outlets is 
selected depending on the desired air conditioning mode and cold air or 
hot air is blown-off exclusively from the selected air outlet at a 
controlled flow rate while closing the other air outlet, thereby 
increasing the air conditioning efficiency. 
However, such desirable air conditioning is not attained by the known 
diffuser unit described above because the flow rate of blown-off air from 
each respective air outlet is not controlled independently. Any angular 
movement of the damper to adjust the flow rate of blown-off air from the 
selected air outlet will necessarily cause the non-selected air outlet to 
be partially opened, thereby letting cold air or hot air pass through the 
non-selected air outlet. Due to this unintended air distribution, an 
efficient air conditioning is difficult to achieve. 
SUMMARY OF THE INVENTION 
It is accordingly an object of the present invention to provide a diffuser 
unit for air conditioning systems which is capable of adjusting the flow 
rate of blown-off air while directing a stream of blown-off air to a 
desired direction. 
The foregoing and other objects are attained by a diffuser unit for air 
conditioning systems, comprising: 
an air supply duct having an air inlet and two air outlets; 
two dampers for regulating the open area of the two air outlets; and 
a linkage mechanism operatively connecting the dampers with a drive means 
for moving a selected one of said two dampers while holding the other 
damper in its closed position. 
With this construction, only the selected damper is angularly moved to 
adjust the flow rate of blown-off air passing therethrough. Furthermore, 
the air outlets are opened and closed independently from one another. The 
open area of each air outlet is variable with the angular displacement of 
a rocking plate. 
Many other advantages and features of the present invention will become 
manifest to those versed in the art upon making reference to the detailed 
description and the accompanying sheets of drawings in which a preferred 
structural embodiment incorporating the principles of the present 
invention is shown by way of illustrative example.

DETAILED DESCRIPTION 
A preferred embodiment of the present invention is described below with 
reference to the accompanying drawings. 
As shown in FIGS. 1 and 2, a diffuser unit embodying the invention includes 
an air supply duct 1 mounted on the ceiling 2 of a house or a vehicle. The 
duct 1 has an elongate hollow body of a generally T-shaped cross section 
and includes an air intake portion 4 projecting through the ceiling 2 into 
a space above the ceiling 2, a pair of first and second air discharge 
portions 5a, 5b extending contiguously from an inner end of the air intake 
portion 4 in substantially opposite directions and overlying the inner 
surface of the ceiling 2, and a power unit chamber 7 defined at an end of 
the duct 1 and separated from the discharge portions 5a, 5b by a partition 
wall 6. The first discharge portion 5a has a first air outlet 9a facing in 
a direction parallel to the general plane of the ceiling 2. Likewise, the 
second discharge portion 5b has a second air outlet 9b facing in a 
downward direction perpendicular to the general plane of the ceiling 2. A 
plurality of parallel spaced first baffle plates 8a are disposed in the 
first discharge portion 5a adjacent to the first air outlet 9a. A 
plurality of parallel spaced second baffle plates 8b are disposed in the 
second discharge portion 5b adjacent to the second air outlet 9b. The air 
intake portion 4 has an air inlet 10 facing in an upward direction 
perpendicular to the general plane of the ceiling 2. The temperature 
controlled air supplied from a non-illustrated air conditioning unit is 
introduced through the air inlet 10 into the duct 1. The air is then 
blown-off from a selected one of the air outlets 9a, 9b in which instance 
the direction and the flow rate of blown-off air are adjusted by first and 
second dampers 11, 12. 
Each of the first and second dampers 11, 12 is composed of a damper body 
11a, 12a and a cushioning member 11b, 12b overlying the damper body 11a, 
12a. The dampers 11, 12 are connected at one end to a pair of parallel 
spaced drive shafts 13a, 13b, respectively, pivotably disposed between the 
first and second air outlets 9a, 9b. The other or distal end of each 
damper 11, 12 is bent arcuately so as to prevent the generation of wind 
noise. The arcuate portion of the distal end of the damper 11, 12 is 
sealingly engageable with a lining 14 of the duct 1 when the damper 11, 12 
is held in its closed position. The dampers 11, 12 are normally urged 
toward their closed positions by means of torsion springs (not shown) 
disposed around the respective drive shafts 13a, 13b and acting between 
the duct 1 and the dampers 11, 12. The dampers 11, 12 are operatively 
connected with a drive means or unit 15 via a linkage mechanism described 
later on. 
The linkage mechanism includes first and second levers 16a, 16b operatively 
connected with the first and second dampers 11, 12, respectively, and 
movable in unison with the latter, and a rocking plate 17 coupled with the 
levers 16a, 16b. The levers 16a, 16b are connected with ends of the 
respective drive shafts 13a, 13b extending through the partition wall 6 
into the power unit chamber 7. The levers 16a, 16b extend perpendicular to 
the axes of the drive shafts 13a, 13b and have lateral pins projecting 
perpendicularly from the distal end of the levers 16a, 16b. As best shown 
in FIG. 3, the rocking plate 17 is in the form of a sector and connected 
at its lower end to a dirve shaft 21 of the drive unit 15 such as a 
reversible motor actuator. The rocking plate 17 thus connected is turned 
about the drive shaft 21 in opposite directions when the motor actuator 15 
is energized. The rocking plate 17 includes a central sector portion 20 
having an arcuate peripheral edge 19, first and second radial arms 22a, 
22b disposed on opposite sides of the sector portion 20 and projecting 
radially outwardly beyond the arcuate peripheral edge 19, and first and 
second radial grooves 23a, 23b defined respectively between the first arm 
22a and the sector portion 20 and between the second arm 22b and the 
sector portion 20, the radial grooves 23a, 23b being contiguous to the 
arcuate peripheral edge 19. 
The rocking plate 17 is disposed in confronting relation to the first and 
second levers 16a, 16b in such a manner that the arcuate peripheral edge 
19 of the sector portion 20 slidingly engages the lower surfaces of the 
pins 18a, 18b on the levers 16a, 16b upon angular movement of the rocking 
plate 17. When the dampers 11, 12 are disposed in their closed positions, 
the pins 18a, 18b on the respective levers 16a, 16b are held in abutment 
with corresponding arms 22a, 22b. When the rocking plate 17 is turned in 
one direction, one of the pins 18a, 18b is forced by the corresponding arm 
22a, 22b to move into the radial groove 23a, 23b while the other pin 18b, 
18a slides along the arcuate peripheral edge 19 of the sector portion 20. 
As described above, the dampers 11, 12 are normally held in closed 
positions. When the rocking plate 17 is turned in a direction indicated by 
the arrow shown in FIG. 3, the pin 23a on the first lever 16a is guided 
into the raidal groove 23a. At the same time, the lever 16a is tilted in 
the same direction as the rocking plate 17, thereby progressively opening 
the first outlet 9a to an extent proportional to the tilted position of 
the damper 11. During that time, the pin 18b on the second lever 16b 
slides along the arcuate peripheral edge 19 of the sector portion 20 with 
the result that the second damper 12 remains immovable in its closed 
position. 
With this arrangement, the opening area of one air outlet is adjusted 
independently from the other outlet. One of the air outlets 9a, 9b is 
selected according to the temperature of air, i.e. the desired air 
conditioning mode. 
For instance, when cold air is supplied to the duct, the first air outlet 
9a is opened. The cold air is therefore blown-off from the first air 
outlet 9a along the ceiling 2 at a flow rate proportional to the angular 
position of the damper 11, i.e. the open area of the first air outlet 9a. 
Conversely, when the supplied air is hot, the second air outlet 9b is 
opened. The hot air is blown-off from the second air outlet in a downward 
direction at a flow rate proportional to the angular position of the 
damper 12, namely the open area of the second air outlet 9b. 
It is possible, according to the invention, to vary the position of the 
dampers 11, 12 in a stepwise manner. Further, the pivot angle of the 
rocking plate 17 may be adjusted depending on the temperature of a room to 
be air-conditioned. The levers 16a, 16b may be connected to a single drive 
shaft. As a further alternative, the levers 16a, 16b may be connected 
directly to the respective dampers 11, 12. 
Obviously, various modifications and variations of the present invention 
are possible in the light of the above teaching. It is therefore to be 
understood that within the scope of the appended claims the invention may 
be practiced otherwise than as specifically described.