Whole house ventilating method, system and appartus

A method of and apparatus for controlling air flow through the medium of a circular frame structure upon which is pivotally mounted a plurality of shutters, the frame being adapted to be secured to a ceiling of a room or space in which ceiling an opening has been cut to accommodate air flow and movement of the pivotally mounted shutters. The circular frame structure and shutter assemblage is substantially flush with the plane of the ceiling and a housing and ventilating fan is disposed in an attic or space above the opening in the ceiling. The ventilating fan above the shutters is rotated in a direction to draw air from the room upwardly into the attic space for dissipation through conventional air vents located in the roof or wall region of an attic space. The circular support frame structure and the shutters are molded of resinous plastic material and the shutters are pivoted by pivot pins integral with the shutters which are pivotally mounted in the circular portion of the frame structure and in a central support means or region of the frame structure.

TECHNICAL FIELD 
This invention relates to a method, system and apparatus for ventilating a 
whole house through the medium of a ventilating fan disposed above an 
opening in the ceiling below an attic space, the latter having 
conventional outside vents, The method, system and apparatus embody an 
assemblage of movable shutters or vanes arranged in an opening in the 
ceiling which are normally closed when the circulating fan is not in 
operation and which are automatically opened by reduced air pressure above 
the shutters set up by rotation of the ventilating fan in a direction for 
exhausting air from the room or whole house area and delivering the air 
through the conventional vent openings in the walls or roof of the attic 
space. 
DISCLOSURE OF THE INVENTION 
The present invention relates to a method, system and apparatus for 
ventilating a whole house through the medium of a ventilating fan disposed 
above an opening in the ceiling and which is enclosed in a housing or 
shroud in the attic space which has conventional outside vents in the 
walls or roof structure of the attic. Disposed in the opening in the 
ceiling is an assemblage of movable shutters or vanes below the fan 
housing or shroud, the shutters being actuated to open positions by 
reduced air pressure below the fan resulting from operation of the 
circulating fan to vent the whole house or the room beneath the ceiling by 
an air stream which automatically opens the shutters during operation of 
the fan for exhausting air from the whole house or space below the ceiling 
and the air exhausted from the space or whole house being driven through 
the conventional vent openings provided in the walls or roof structure 
when the fan is in operation. 
The shutter arrangement for the whole house ventilating system may be 
readily installed in an opening in the ceiling below an attic space in a 
house already constructed or installed in a new house construction. The 
shroud or housing of the circulating fan may be readily mounted upon a 
subframe supported by ceiling joists, the assembly of movable shutters 
being arranged in the ceiling opening whereby the shutters when in closed 
position are in substantially the plane of the ceiling. The fan housing, 
the circulating fan and the motor operating the fan are supported by the 
supplemental frame, and when the shutters are in open position the air is 
exhausted through the fan housing into the attic and the air dissipated 
from the attic through conventional vents in the attic walls or roof 
construction. As the assembly of movable shutters and the circulating fan 
are adjacent the ceiling structure below an attic space, the circulating 
fan and the movable shutters are not subjected to adverse weather 
conditions. 
An important feature of the invention is the provision of a shutter 
construction for controlling air flow, the shutter construction including 
a circular or annular support frame structure having a central support 
means and wherein a plurality of shutters are pivotally supported upon the 
circular region of the support frame and the central support means, the 
structure being of such character that the frame structure and the 
shutters may be readily mounted in an opening in a ceiling construction of 
a room or space.

BEST MODE FOR CARRYING OUT THE INVENTION 
The method, system and apparatus of the invention involve a ventilating 
apparatus for venting a house through a movable shutter arrangement in an 
opening in a ceiling of a room or space with a ventilated attic or space 
above the room and an air moving means above the shutter arrangement. The 
apparatus is inclusive of a frame structure supporting a plurality of 
movable shutters or vanes which, when closed, are substantially in the 
plane of the ceiling of the room, and which shutters or vanes are opened 
by an air stream set up by a fan disposed in a housing or shroud in the 
attic space above the shutters. The fan is rotated in a direction to 
provide reduced air pressure above the shutters or vanes whereby the 
pressure in the room or house being ventilated causes the shutters or 
vanes to be swung or moved upwardly to an open position and the air from 
the room or house is delivered through the attic or attic space to the 
outside atmosphere through conventional vents in the walls or roof 
structure of the attic. 
Referring initially to FIGS. 1 and 2, there is illustrated a ventilating 
fan and one form of frame and shutter arrangement mounted in an opening in 
the ceiling of a room above which is a ventilated attic space. The shutter 
arrangement or assembly 10 comprises a plurality of movable vanes or 
shutters pivotally mounted by a support frame in an opening in the ceiling 
14 of the space or house being ventilated and the ventilating fan and 
housing or shroud construction 12 extends into the attic or attic space 
above the ceiling. 
A circular opening is cut in the ceiling 14 to accommodate the shutter 
arrangement or assembly 10. Disposed above the ceiling construction 14 are 
conventional joists, three of which are indicated at 16, 18 and 20. The 
fan housing or shroud 22 is of circular cylindrical shape as particularly 
shown in FlGURE 1. The shroud or housing 22 preferably comprises a strip 
of comparatively thin metal formed into an annulus with the ends of the 
strip overlapping and secured together by rivets 24. The housing or shroud 
may be cast or molded of suitable material to a circular configuration. 
A subframe or frame structure 26 is provided for supporting the fan and 
housing assembly from the joists. The subframe 26 comprises two strips 28 
of wood extending transversely across the joists. Disposed between the 
strips 28 are wood strips 30, the strips 28 being secured to strips 30 by 
means of nails 31. The subframe 26 is supported by engagement of the 
strips 28 with the joists 16, 18 and 20. The strips 28 and 30, when 
assembled, are of a dimension to receive the housing or shroud 22 as shown 
in FIG. 2. 
The strips 28 are nailed to the joists 16 and 18 by toed nails 32. As shown 
in FIG. 2 the fan housing or shroud 22 is secured to the strips 28 and 30 
by means of screws 34. The central axis of the fan housing or shroud 22 
passes through the center of the joist 18. The fan 36 comprises a 
plurality of fan blades 37 which are mounted upon a central hub member 38, 
the hub member 38 being mounted upon a shaft 39 of an electrically 
energizable motor 40. The fan 36 is driven by the motor 40. 
A motor supporting frame or bracket means 42 is of one piece construction 
preferably of metal having four outwardly extending arm portions 44, two 
of which are shown in FIGURE 2, which are integrally connected together by 
a central portion 48. The housing of the motor 40 is secured to the 
central portion 48 of member 42 by means of bolts 50. The four arm 
portions 44 project to the interior surface of the housing or shroud 22. 
Each of the end regions of the projections 44 is fashioned with a flange 
52 which is secured to the support or shroud 22 by rivets 53. Through this 
means the motor is rigidly supported from the housing or shroud 22. 
The fan blades 37 are of a length slightly less than the inner diameter of 
the housing or shroud 22 as shown in FIG. 2 so as to have a minimum 
running clearance within the housing or shroud 22. The electrically 
actuated motor 40 may be controlled by a switch means (not shown) mounted 
within the room or space defined below the ceiling 14 for convenient 
operation of the motor. 
The fan blades, as shown in FIG. 2, are contoured so that when the motor 
rotates the fan in a counterclockwise direction the fan blades move air 
upwardly through the housing or shroud 22 and exhaust the air into the 
attic where the air flows outwardly through the attic vents. 
The shutter assembly 10 is inclusive of a plurality of generally circular 
sector-shaped shutters or vanes 60. The vanes or shutters are particularly 
shown in FIGS. 2 and 3. The shutters are illustrated in closed position in 
FIGS. 2 and 3 in which position the shutters prevent flow of air from the 
attic to the room or house being ventilated. 
The shutters or vanes 60 are supported by and journaled for movement 
relative to a circular or annular frame or member 64 and a central support 
means or member 70. It should be noted from FIG. 2 that when the shutters 
60 are in a closed position, the lower surfaces of the shutters are 
substantially in the plane of the lower surface of the ceiling 14. The 
circular or annular frame 64 is fashioned of molded resinous plastic 
material such as high impact polystyrene. 
Extending transversely at the mid region of the frame is a bar or member 66 
of resinous material molded integrally with the annular frame 64. 
Integrally molded with the member or bar 66 and the circular frame 64 at 
its central region is the support member 70 supporting the inner ends of 
the vanes or shutters 60 in a manner hereinafter described. 
Each of the sector-shaped shutters or vanes 60 is formed at one radial edge 
with a ridge portion 72 of circular cross section as shown in FIGS. 4 and 
5, the circular cross section of the member 72 extending beyond the outer 
circular edge of a shutter 60 forming a cylindrical pintle, pin or shaft 
74 as shown in FIG. 6 which is also of plastic material as each of the 
shutters 60 is of molded resinous material such as high impact 
polystyrene. 
The annular or circular frame member 64 is fashioned with a circular flange 
76 which is integrally joined with a circular or cylindrical wall or band 
78, the band 78 being concentric with the flange 76 as shown in FIGS. 3, 6 
and 8. The circular band 78 adjacent each of the pintles 74 is provided 
with a slot 79 terminating in flat base portions 80 as shown in FIG. 6. 
The band 78 is provided with comparatively narrow slots 82 which in 
assembly receive the pintles 74 of the shutters or vanes 60. 
The molded resinous central support means 70 has portions 84 of reduced 
thickness, shown in FIG. 9, adjacent the pintle, pin, or shaft portion 86 
extending inwardly from each of the shutters 60. The reduced portions 84 
of the central member 70 molded integrally with the bar 66 and the 
circular frame 64 have slots 88 for receiving the pintles, pins or shaft 
portions 86 of the shutters or vanes 60 as shown in FIGURES 9 and 11. 
Thus the outer pins or pintles 74 of the shutters 60 are received in slots 
82 in the circular band 78, and the inner extending pins or pintles 86 of 
the shutters 60 are received in slots 88 in the central support portion 
70. In this manner each of the shutters 60 through the engagement of its 
pintles 74 and 86 in the respective slots 82 and 88 provides a pivotal 
mounting for each of the shutters in the circular frame or support 64 and 
the central support means 70. 
The opposite radial edge region of each of the shutters 60 is provided with 
a raised edge extension 92 which overlies the ridge or shaft portion 72 of 
the adjacent shutter or vane 60 in the manner shown in FIG. 5 thus 
providing an overlapping of edge regions of the circular sector-shaped 
shutters or vanes when in closed positions so as to prevent air movement 
through the shutter assemblage from the attic into the living space or 
room beneath the attic. 
As shown in FIG. 2, the lower planar surface of the ceiling 14 is engaged 
by the outwardly extending flange 76 of the circular shutter supporting 
member or frame 64. The cross member 66 integral with the circular support 
frame 64 is in alignment with the center joist 18 shown in FIG. 2. The 
peripheral band 76 of the circular support frame 64 is provided with 
openings 77 adapted to receive securing screws (not shown) for securing 
the frame 64 to the plaster ceiling 14. 
The securing screws extending through the openings 77 in alignment with the 
horizontal member or bar 66 of the support frame are threaded into the 
central joist 18, and the two screws entering the other two openings 77 in 
the band 76 are threaded into threaded clips or nuts (not shown) disposed 
above the plaster ceiling 14 providing additional support for the support 
frame. 
The screws accommodated in the openings 77 secure the center support frame 
64 and the shutter assembly to the ceiling 14 in the position shown in 
FIG. 2. The pintles 74 of the circular ridge 72 on each of the shutters or 
vanes 60 rest in slots 72 in the band portion 78 of the circular support 
frame 76, and the inner extending pintles 86 of the raised or shaft 
portions 72 of each of the shutters or vanes 60 rest in grooves 88 in the 
central support portion 70. 
Thus the pintles on each of the shutters or vanes 60 disposed in the slots 
82 and 88 are rotatable about the axes of the pintles of each of the 
shutters or vanes so that each of the shutters readily opens under the 
reduced air pressure provided by the fan when in operation. 
The apparatus or arrangement includes means for retaining the pintles 74 
and 86 in the notches, grooves or slots 82 and 88 in the support members 
64 and 70 without impairing swinging movement during open and closing 
movements of the shutters or vanes. The means for retaining the pintles 74 
of the shutters or vanes in the slots 82 include a clip, retaining means 
or fastener 96 for each of the pintles, one form of retaining means being 
shown in FIGS. 3, 6, 7 and 8. 
Thus there are eight clips for retaining the eight pintles 74 of the eight 
shutters or vanes in the slots 82 of the support frame 64. Each of the 
clips or retaining means 96 is formed of sheet metal. Each of the 
retainers 96 is of generally U-shaped configuration as shown in FIGS. 6, 7 
and 8 having a central portion 98 and side walls 100 and 102. 
The space between the side walls 100 and 102 is of a dimension to be snugly 
received over the adjacent portions of the band portion 78 of the frame or 
support 64. The lower central region of the wall 100 is provided with a 
projection, pad or tab portion 104 which extends substantially at right 
angles to the wall portion 100 as particularly shown in FIGS. 6 and 8. 
When the clip or retaining means 96 is assembled with the circular frame 
member 64 as illustrated in FIG. 8, the flat or planar surface of the pad 
or tab portion 104 is adjacent the pintle 74 so that during swinging 
movements of the shutter the metal pad will not cause any wearing or 
abrasion o the pintle 74 which is of resinous plastic material. 
The outer wall 102 of each retainer 96 is fashioned with inwardly extending 
projections or lug portions 106 which are bent inwardly as in FIGS. 6 and 
8 so that when a clip or retainer 96 is assembled in position on the band 
portion 78 of the circular frame 64, the edge regions of the projections 
or lugs 106 snugly or frictionally engage the band 78 so as to retain the 
clip or retainer 96 on the band 78 of the circular support member 64. 
Each of the base portions 98 of the retainers 96 is fashioned with a tab, 
stop means or member 108 which is engaged by a shutter 60 when the same is 
moved by the air stream to an open position, the edge region of the 
shutter 60 engaging the stop means 108 when the shutter is open to the 
position shown in broken lines at 60' in FIG. 8. 
This stop means limits the opening movement of each of the shutters 60 so 
that when the ventilating fan motor is deenergized all of the shutters 60 
will return by the force of gravity into their proper closed positions 
where one shutter overlaps another shutter as illustrated in FIGS. 3, 4 
and 5. The retaining means, retainers or clips 96 maintain the pintles 74 
in the recesses 82 in the band 78 in all positions of the shutters. 
It has been previously pointed out that the inner pins, pintles or shaft 
portions 86 of the molded plastic shutters 60 extend into the recesses 88 
in the central support portion 70 of the frame 64. The pins, pintles or 
shaft portions 86 are retained in the recesses 88 by means of metal 
retainers, clips or fasteners 112 shown in FIGS. 3, 9, 10 and 11. 
The retaining means, clips or fasteners 112 are similar to the clips, 
retainers or fasteners 96. Each of the retainers, clips or fasteners 112 
is of generally U-shaped configuration comprising a base portion 114 
andside walls 116 and 118. The lower central edge region of the side wall 
116 is provided with a tab or projection 120 integral with and extending 
inwardly of the wall 116 and overlapping the edge of the wall 118 as shown 
in FIG. 10. 
When a retaining means, clip or fastener 112 is assembled with the central 
member portion 70 in the manner shown in FIG. 11 the flat or planar 
surface of the tab or projection 120 is above the pintle 86 so that the 
metal of the clip or retaining means 112 will not abrade or bind against 
the plastic pintle 86. 
The wall 118 of each of the retaining means, clips or fasteners 112 is 
formed with inwardly extending lugs or projections 122. When the retaining 
means, clips or fasteners 112 are assembled with the central support 
portion 70 of the frame 64 in the manner illustrated in FIG. 11, the sharp 
edges of the inwardly extending projections 122 of each of the clips 
snugly engages the portions 84 of the central support member portion 70 so 
that the clips or retainers 112 are prevented from dislodgment after they 
are assembled to hold the pintles 86 in the recesses or slots in the 
manner shown in FIG. 11. 
In such assembled positions the flat surfaces of the metal tabs or 
projections 120 are adjacent the cylindrical plastic pintles or pins 86 
molded with the shutters 60 so that the pintles will not be abraded by the 
metal retainers by reason of pivotal movement of the shutters. 
The sharp edges of the lugs 106 of the retainers 96 and the sharp edges of 
the lugs 122 of the retainers 112 tend to bite into the resinous plastic 
material of the band 78 and the portions 84 of the central portion 70 of 
the circular frame structure 64 so that the retainers will be frictionally 
secured to the band 78 and the portions 84 of the support portion 70 of 
the frame thereby retaining the pintles of the shutters in the slots 
without impairing free movement of the shutters to open and closed 
positions. 
Referring to FIGS. 1 and 2 it will be noted that the lower edge of the 
shroud or housing 22 terminates adjacent the lower edges of the frame 
members 28 and 30 of the subframe or supplemental frame 26. Disposed 
between the flange 76 of the circular support frame 64 and the lower 
terminus of the shroud or housing 22 is an open space equal to the height 
of the joists 16, 18 and 20. 
Enclosing this space is a housing extension comprising strips 126 of metal, 
such as aluminum, which form a continuation of the cylindrical housing or 
shroud 22, the strips engaging the upper surface of the flange portion 76 
of the circular frame 64. 
These strips 126 forming an enclosed extension of the housing or shroud 22 
are of the contour of the circular housing or shroud 22 and are secured to 
the center joist 18 so that when the shutters 60 are in open position the 
upwardly directed air stream provided by the rotation of the ventilator 
fan 36 will cause the shutters to be opened to ventilate the space or 
house area below the ceiling 14. 
The upper portion of the metal strips 126 may be overlapped if desired with 
the lower edge region of the shroud or housing 22 and the junctures of the 
strips 126 with the housing or shroud 22 are covered with adhesive or duct 
tape 128 shown in FIG. 1 so that there is no leakage of air at the 
juncture of the shroud or housing 22 with the strips 126. 
When the circulating fan 36 is not operating, the circular sector-shaped 
shutters 60 are in closed position and completely obstruct movement of air 
between the attic space and the whole house or room area below the ceiling 
14. The switch for controlling the electrically operated motor 40 for 
rotating the fan 36 may be disposed in any desired position for 
convenience in operation anywhere in the house. 
It is important to the most efficient operation of the ventilating system 
to have the outside air vents of the attic of a size to accommodate the 
exhaustion of air from the attic space sufficient to provide an air stream 
effective to open the shutters 60 to their full open or near open 
position. 
For an average circulating fan of a diameter of about twenty inches the 
vent openings for the attic space should total about seven hundred twenty 
square inches of free ventilating area to assure movement of the air 
stream through the fan housing or shroud 22 to effectively open the 
shutters 60 of the shutter assembly. 
If a larger diameter circulating fan is utilized the area of the attic air 
exhaust vents should be proportionately increased. Through the use of the 
stop means 108 on the clips or retainers 96 the opening movement of the 
shutters 60 to near full open position is attained without the shutters 
reaching a position where they would not return by gravity to their proper 
overlapping relation in closed position. 
Through the provision of shutters which, in closed position, are 
substantially in the plane of the ceiling 14, the closed shutters do not 
present an unsightly appearance in the room or living space of a building 
or house, and the shutters, when in closed position, prevent flow of air 
from the attic into the room or living space of a building or house. 
FIGS. 12 through 21 illustrate a modification of frame structure and 
shutter assembly particularly for use with a ventilating fan housing and 
fan construction of larger size, for example, for use with a housing of an 
inner diameter of about thirty inches or more and a fan of slightly less 
diameter. In this form of the invention the shutter support frame 
construction 130 comprises two sections or components 131 and 132, each 
component being of semiannular or semicircular shape. 
The component 131 has a semicircular planar configuration 133 and the other 
component 132 has a semicircular planar configuration 133'. The component 
131 has a central support means, section or portion 135 and the component 
132 has a central support means, section or portion 135'. 
FIG. 12 illustrates each of the frame components 131 and 132 in 
disassembled relation and FIGS. 13 and 14 illustrate these components in 
assembled relation. 
The end regions of the semicircular configuration 133 of the component 131 
are joined with the central support means or section 135 by a bar or 
member 138 and the end regions of the semicircular configuration 133'of 
the component 132 are joined with the central support means or section 
135' by a bar or member 138'. The semicircular configuration 133 of the 
component 131 is also joined by a bar 140 with the central support means 
or section 135 and the semicircular configuration 133' of the component 
132 is joined with the central support means, section or portion 135' by a 
bar or member 140'. 
FIG. 18 illustrates the cross sectional shape of the bar 140, and the cross 
sectional shape of the bar 140' is of the same configuration. The 
component 131 comprising the semicircular configuration 133, the bar or 
member 138, and the bar or member 140 are formed and joined integrally by 
molding and preferably fashioned of resinous plastic material such as high 
impact polystyrene. 
The component 132 comprising the semicircular configuration 133', the bar 
or member 138', and the bar or member 140: are joined integrally by 
molding and preferably fashioned of resinous plastic material such as high 
impact polystyrene. The bars 138 and 138' are formed with regions which 
are interlocked for securing the two components in assembled relation as 
shown in FIGS. 13 and 14. Reference is made to the sectional view, FIG. 
15, which shows an arrangement for interlocking and securing the 
components 131 and 132 together in assembled relation as shown in FIG. 14. 
In FIG. 15 the portion 144 of the bar or member 138 is provided with two 
parallel spaced portions or furcations 146 extending from the circular 
configuration 133 to the central support section 135. The portion 144 has 
a reinforcing ridge 148 to impart rigidity to the bar or member 138. 
The adjacent portion of the bar 138' below the central section 135 is 
provided with a portion 150 which extends between the furcations 146 as 
shown in FIG. 15. The furcations 146 overlapping the portion 150 in FIG. 
14 are provided at their lower ends with registering openings 152 which 
receive a screw (not shown) for securing the lower ends of the 
semicircular configurations 133 and 133' together. 
If a joist is in alignment with the furcations 146 the screw in the 
openings 152 will be threaded into the joist to support the frame 130 from 
the joist. The furcations 146 on the portion 138 below the center of the 
assembly terminate just below the central support means 135'. As shown in 
FIG. 15 the portion 138' is provided with a reinforcing ridge 148'. 
It should be noted in FIGS. 12 and 14 that the portions of the upper half 
of the bar or member 138' are reciprocal or in reverse position to the 
same portions in the lower half below the central support means 135'. Thus 
in the upper half of the bar 138 the portion 150' is between the 
furcations 146', one of which is shown in FIG. 14, and the portion 144' in 
FIG. 14 is between the furcations 146'. 
The portion 144' and the furcations 146' in assembly have registering 
openings 152' to receive a screw (not shown) for holding the upper 
portions of the semicircular configurations 133 and 133' in assembled 
relation. If a joist is above the bar 138, the screw in the opening 152 
may be threaded into the joist as support means for the support frame 130. 
The semicircular frame portions 133 and 133' have openings 156 which 
register with openings in the ceiling and are adapted to receive screws 
threaded into nuts or clips (not shown) above the ceiling as added means 
for securing the frame structure 130 to the ceiling. 
The support frame 130 and the central support means 135 and 135' are 
adapted to support a plurality of shutters. It will be noted from FIGS. 
12, 13 and 14 that in the embodiment illustrated there are twelve 
shutters. The shutters are in two groups of six shutters in each group. 
The shutters in the right-hand group in FIG. 14 are designated 160 and the 
shutters in the left-hand group are designated 160' Each of the shutters 
is preferably molded of resinous plastic material such as high impact 
polystyrene. 
Each of the shutters 160 and 160' is provided along one edge with a ridge 
162 of circular cross section which terminates at its end regions in 
cylindrical pivot pins, pintles or shaft portions 163 and 174. As shown in 
FIG. 21 each of the circular portions 133 and 133' of the components 131 
and 132 is provided with a horizontal flat or planar circular portion 165 
having an outer upward circular flange 167 and an inner circular flange 
169. The outer upstanding flange 167 engages the ceiling just outside of 
the hole that is cut in the ceiling to accommodate pivotal movement of the 
shutters. 
Spaced outwardly of the inner flange 169 is an upstanding circular portion 
or band 171. The band 171 of each of the circular configurations 133 and 
133' is provided with openings receiving the cylindrical pins, pintles or 
shaft portions 163 thereby providing a pivotal support for the outer ends 
of each of the shutters on the semicircular frame configurations 133 and 
133'. 
Means is provided at the central support means 135 and 135' for pivotally 
supporting pivot pins, pintles or shaft portions 174 provided on the inner 
ends of the shutters 160 and 160'. Reference is made to FIG. 20 which 
illustrates the mounting arrangement supporting the shutter pins 174 and 
the retainer means for maintaining the pins 174 in slots in central 
portions 135 and 135'. The retainer means associated with the central 
portions 135 and 135' are substantially the same except that the means 135 
has a portion 150 extending between the furcations 146. 
FIG. 19 illustrates one of the retainer means for retaining the pivot pins, 
pintles, or shafts 174 in slots in the central support means 135 and 135'. 
In further reference to FIG. 20 the means 135 and 135' have upwardly 
extending flanges 178 which are engaged by the pins 174 of the shutters 
160 and 160'. 
The central support means 135 has an upwardly extending flange 180 and the 
central support means 135' has an upwardly extending flange 180'. The 
upper portion of the flanges 180 and 180' are provided with slots which 
receive the pivot pins 174 on the inner ends of the shutters. 
A retaining means or member 182 is for retaining the pins or pintles 174 on 
the inner ends of the shutters 160' in slots in the flange 180, and the 
retainer means 184 is for retaining the pins 174 of the shutters 160 in 
the slots in the portion 180'. 
As shown in FIG. 19 the retainer means 182 has two depending portions 186 
and 187 which fit inside the upwardly extending projections 180 on the 
support section 135. The horizontal portion of the retaining means 182 is 
fashioned with square projections 188 having slots or openings 189. 
Extending upwardly from the horizontal portion 135 in FIGURE 19 are two 
projections 190, the upper end of each of the projections 190 having a 
laterally extending tooth or lug 191 which engages and hooks over a 
portion 192 projecting into the openings 189. 
As the upwardly extending portions 190, shown in both FIGS. 19 and 20, are 
of resinous plastic material they have a certain amount of flexibility so 
that normally when the retainer 182 is snapped into pin retaining 
engagement, the members 190 are flexed so that the teeth 191 hook over the 
projecting portions 192 of the retaining means or retainer 182. 
The retainer 184 is of the same construction as the retainer 182 and 
retains the pins 174 of the shutters 160 in the grooves in the flange 
180'. In this manner the inner pins or pintles 174 of the shutters are 
pivotally supported on the central support means or structures 135 and 
135'. 
FIG. 17 illustrates the overlapping relationship of a shutter with an 
adjacent shutter. Each of the shutters has a ridge 162, and an edge of the 
adjacent shutter is provided with a raised portion 195 shown in FIG. 17 
adapted when the shutters are in closed position to overlap the adjacent 
shutter in the manner illustrated in FIG. 17. 
FIG. 18 illustrates the ridge 162 of a shutter 160' in close position to an 
upwardly extending portion 196 of the member 140. Another portion 196' on 
the member 140 is engaged by a shutter 160' in the manner shown in FIG. 18 
when the shutters are in closed position. 
Means is provided for limiting the open position of each of the shutters. 
As shown in FIGS. 16 and 21, the horizontal portion 165 of each circular 
configuration 133 and 133' is fashioned adjacent the outer end of each 
shutter with an upwardly extending projection 197, and the edge of the 
shutter is provided with a projection 198 which extends laterally of each 
of the shutters. lt will be noted from FIG. 16 that when a shutter is 
rotated in a clockwise direction from closed to open position, each 
lateral projection 198 will engage a stationary projection 197 to limit 
the open position of each of the shutters. This feature is important in 
that it enables the shutters to readily move to closed position by force 
of gravity when air flow ceases through the shutter assembly. 
Through the provision of two components 131 and 132, each group of shutters 
may be preassembled with a component and the components with the shutters 
assembled therewith may be brought together as shown in FIGS. 13 and 14 
during installation of the assemblage in the hole in the ceiling. 
Through the utilization of a large number of shutters, the shutters may be 
of smaller size and hence of lighter weight so that the air stream created 
by the ventilating fan will readily open all of the shutters. 
It is apparent that, within the scope of the invention, modifications and 
different arrangements may be made other than as herein disclosed, and the 
present disclosure is illustrative merely, the invention comprehending all 
variations thereof.