High thermal efficiency window

A high thermal efficiency window which is comprised of a low conductivity ame carrying a spaced pair of panes or lites. The space between the panes is divided into a series of vertically spaced-apart cells by a blind structure disposed between the panes, the slats of the blinds being essentially in contact with the interior faces of the panes whereby convection losses are minimized. The device is characterized by the blind being shiftable between an open or see-through configuration and a privacy configuration, the longitudinal edges of the elements defining the blinds being in contact with the interior faces of the panes in both said see-through and privacy configurations thereof.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention is in the field of windows and is directed more 
particularly to a thermal window construction having minimum heat transfer 
looses. 
The invention is more particularly directed to an improved window of the 
type having two or more panes, a blind structure being interposed between 
the panes, the blind being shiftable between privacy and see-through 
configurations. 
2. The Prior Art 
With the increasing costs of energy, greater emphasis is placed upon the 
provision of window structures having minimal heat loss. Numerous 
expedients have been relied upon to reduce heat loss through window 
devices. Such expedients have included the provision of double pane 
windows, the frame portion of which has been formed either of a low 
conductivity material such as wood or plastic or, where high conductivity 
materials are used, the provision of a thermal break between inner and 
outer high conductivity components. 
It is also known, in order to reduce convection losses resulting from 
currents generated within the space between the panes, to employ blind 
structures, such as Venetian blinds. 
Desirably, such blind structures are adjustable to pass maximum radiation 
during the winter and minimum radiation during the summer. 
U.S. Pat. Nos. 2,239,528 of Apr. 22, 1941 to Knudsen, 3,022,549 of Feb. 27, 
1962 to Cummings, 4,076,068 of Feb. 28, 1978 to Archer, 4,091,592 of May 
30, 1978 to Berlad, for example, pertain to blind structures interposed 
between the glass panes of a window structure. Such blind structures, when 
they are adjusted to their so-called see-through condition wherein the 
blades or slats defining the blind are essentially horizontally arrayed, 
tend to divide the space between the windows into a series of vertically 
stacked air spaces which reduce heat loss through convection to a greater 
degree than if the entire space between the panes were not subdivided. 
From the standpoint of thermal efficiency, the blind structures heretofore 
known lose much of their convection impeding function when the same are 
shifted from a see-through to a privacy mode. The reason for such loss is 
that in the see-through mode the slats defining the blinds extend 
substantially across the entire space between the panes and function as an 
effective means for dividing the space into vertically stacked seals. 
However, as soon as the slats of the blinds are tilted to provide a 
privacy mode, the edge portions thereof are shifted away from the inner 
surface of the panes, with resultant formation of spaces adjacent the 
panes, with consequent increase in convective activity and resultant heat 
loss. 
SUMMARY OF THE INVENTION 
The present invention may be summarized as directed to an improved thermal 
insulating window of the type which comprises a convection resistant frame 
carrying two or more parallel panes or lites of glass. The space between 
the panes is occupied by a blind structure which is shiftable between a 
see-through and a privacy mode. In accordance with the invention, the 
blind structure, in both the see-through and privacy modes maintains a 
closed cell condition wherein convection losses experienced in window 
structures heretofore known are eliminated in all modes or positions of 
the blind. 
The invention is further directed to a device of the type described wherein 
adjustment of the blind between its see-through and privacy modes is 
readily effected and the apparatus for achieving such adjustment is simple 
and inexpensive. 
Still more particularly, the present invention is directed to a thermal 
window device wherein two or more panes or lites of glass are supported in 
spaced parallel relation and between which panes there is mounted a blind 
structure including a first series of slats having longitudinal edges 
engaging a inner face of one pane, the slats extending part way toward the 
other pane. A second series of slats is supported with its longitudinal 
edges engaging against or disposed immediately adjacent the other pane, 
the slats of the second series extending part way toward the first 
mentioned pane. The edge portions of the slats overlap, with the free 
edges of the slats of one series resting upon and being supported by the 
slats of the other series. 
The slats of both series are pivotally mounted about horizontal pivot axes 
coincident with or closely adjacent the respective panes. 
Operating means are provided for lifting the free edges of the overlapped 
series of slats whereby a concomitant and opposite tilting movement is 
applied to the overlapping series of slats, whereby the slats of the first 
and second series are angularly oriented relatively to each other to 
provide a privacy mode. 
By appropriate operation of the operator controlling the overlapped series 
of slats, the slats of the first and second series may be arrayed in 
parallelism to provide a see-through function or by an angular orientation 
to provide a privacy function, the pane-adjacent edges of the slats in all 
instances remaining immediately adjacent the inner surfaces of the panes 
whereby a series of closed, vertically offset cells are formed at all 
adjusted positions of the blind, the cells including the panes as 
boundaries in all instances. 
The structure of the invention maintains the sealed cell configuration not 
only in the see-through mode but also in the privacy mode, resulting in an 
improved thermal isolation of interior from exterior environments. 
Accordingly it is an object of the present invention to provide an improved 
thermal window construction. 
A further object of the invention is the provision of a thermal window 
construction of the type described wherein there is included between a 
spaced parallel pair of panes a blind structure shiftable between 
see-through and privacy configurations, the blind structure dividing said 
space into a series of vertically offset closed cells under all conditions 
of operation. 
A further object of the invention is the provision of a device of the type 
described wherein articulation of the blind structure may be accomplished 
without the formation of spaces between the longitudinal side edges of the 
blind structure and the glass panes. 
A still further object of the invention is the provision of a device of the 
type described wherein adjustment of the blind may be accomplished by a 
simple operator mechanism.

Referring now to the drawings, there is shown in FIG. 1 a window 
construction including a frame 10 having a head member 11, a sill member 
12 and side members 13, 14. The frame 10, which has been illustrated with 
a minimum of detail, is comprised either of a material such as wood having 
a high degree of resistance to thermal flow, or may be comprised of 
aluminum or like metal. In the latter case, as is conventional, the frame 
structure may be formed of an inner rectangular frame and an outer 
rectangular frame separated by a thermal break of rubber, vinyl or like 
insulating material to prevent the formation of a high conductivity heat 
bridge between the inside and the outside environments. Since thermal 
break windows are well known per se, there is no advantage to be derived 
from illustrating details of the construction thereof. However, reference 
may be made to Persson U.S. Pat. No. 2,838,109 of June 19, 1958 and 
3,318,360 of May 9, 1967. 
The frame structure 10 supports an inner glass lite or pane 15 and an outer 
glass lite or pane 16, which panes define a space or chamber 17 
therebetween. 
A blind structure 18 is disposed within the space 17, which blind structure 
in all modes of operation divides the space 17 into a series of vertically 
displaced cells 19, 19', 19". As is known, division of the space 17 into a 
series of discrete cells running essentially the entire width of the 
window minimizes convective currents which form a significant means of 
heat transfer between the inner and outer panes. 
The blind structure 18 of the present invention is comprised of a first 
series of slats 20 and a second series of slats 21. The slats 20 of the 
first series have their free edge portions 20' supported immediately 
adjacent or in abutting engagement with the inner face 22 of pane 16 by 
pivotal connection of the slats 20 with the vertically extending ladder 
assembly 23. 
The ladder assembly may comprise merely a series of vertically extending 
fabric tapes 24, 24 adjacent the inner and outer panes, the vertical tapes 
being connected by transversely extending webs or rungs 25. 
Optionally, the free edges 20' of the slats 20 may be pivotally connected 
to the vertical tapes 24 by physical connection at or adjacent the edges. 
Alternatively, the slats 20 may merely be laid atop the transverse webs 
25, the migration away from the tapes 24 being effected in the manner 
hereinafter set forth. 
For optimum isolation and absolute minimized convection losses, the edges 
20' of the slats 20 may be slightly recessed in the areas in registry with 
the tapes 24 such that the edges 20' may extend slightly beyond the tapes 
and into engagement with the inner face of the window pane 16. As a 
practical matter, however, it is sufficient if the edges 20' are separated 
from the inner face of the pane by only the thickness of the tapes, which 
are typically 1/32" or less in thickness. 
Slats 21 are similarly supported on the transversely extending webs or 
rungs 25, with the longitudinal edge portions 21' disposed immediately 
adjacent the inner face of the pane 15. As noted in respect of slats 20, 
an actual physical connection may be effected between the edges 21' and 
the tape 24. However, normally it is adequate to rely upon the parts, as 
hereinafter described, to maintain the desired juxtaposition of the edges 
21' and interior face of the pane 15. 
As may be recognized from an inspection of FIG. 2, for example, the slats 
21 of the second series overlap the slats 20 of the first series. 
The slats 21 are provided with transversely directed slots 26 which are 
disposed perpendicular to the longitudinal axes of the slats--see FIG. 3. 
The slats 20 and 21, while illustrated as being essentially flat, may be of 
a slight arcuate configuration in order to afford additional structural 
integrity. 
The slats 20 and 21 are articulated between the see-through position of 
FIG. 2 and the privacy position of FIG. 4 by an operator member comprising 
one or more vertically directed operator cords 27 extending downwardly 
through the vertically aligned slots 26 of the slats 21. The operator 
member or members 27 are pivotally fixed, as at points 28, to the free 
edge portion 29 of the slats 20. 
The lowermost ends 30 of the cords 27 are affixed to weight levers 31 
recessed in the sill and pivotally secured therein as by pivot pins 32, 
the function of the weight members 30 being to provide a downward 
restoring force to the cords 27 when the same are lifted. 
The upper ends 33 of the cords 27 are secured to a control mechanism 34 for 
lifting and lowering the cords 27. Illustratively the control mechanism 
may be comprised of a cylindrical drum 35 recessed in the head 11 of the 
frame, the rotated position of the drum 35 being governed by a manually 
available control cord or like mechanism (not shown). 
The operation of the device will be apparent from the preceding 
description. 
When the drum 35 is rotated in an anti-clockwise direction from the 
position shown in FIG. 2, the cord or cords 27 will be lifted, causing the 
slats 20 to pivot about pivot points 20' in an anti-clockwise direction. 
The lifting of the slats 20 is accompanied by a clockwise pivotal movement 
of the slats 21, which are stacked or layered atop the slats 20, causing 
the parts to move to the position of FIG. 4 and causing the weighted lever 
31 to shift an anti-clockwise direction. 
Clearance for the pivotal movement of the slats 21 is provided by the slots 
26 in the slats 21. 
The weight member 31 provides a constant downward force maintaining the 
cords 27 in a tautened condition. 
It will be observed from an inspection of FIG. 4 tht when the slats are 
shifted to their privacy position, the weight of the slats of both series 
will tend to urge the pane-adjacent edges thereof 20' and 21' in an 
outward direction or toward the panes. 
It will further be observed that the movement from the see-through to the 
privacy condition is unaccompanied by any movement of the side edge 
portions away from the inner faces of the panes. 
Preferably, stop means are provided for the drum 35, limiting the amount of 
upward movement of the cords 27 to prevent over-lifting or dislocation of 
the blind components. 
When it is desired to return the blind to its see-through condition, it is 
merely necessary to rotate the drum 35 in a clockwise direction, whereby 
the weight 31 draws the cords 27 in a downward direction, carrying with it 
the slats 20 and, concomitantly, the slats 21 which rest atop the slats 
20. 
Although not illustrated, it will be apparent to those skilled in the art 
that the blind structure may be arranged to be lifted entirely as by a 
conventional lift mechanism for storage adjacent the upper edge of the 
window. 
If the device is to be adapted to a lift configuration, it will be evident 
that, in view of the weighted lever affixed to the sill, the weighted base 
slat as conventionally employed in Venetian blind constructions should be 
employed. 
From the foregoing description it will be evident that there is provided in 
accordance with the present invention a thermal window construction 
incorporating a simple blind structure shiftable between privacy and 
see-through configurations and providing in both said configurations a 
plurality of vertically stacked cells employing slats whose pane-adjacent 
edges remain against or in immediate juxtaposition to the opposed inner 
surfaces of the panes in the privacy and see-through configurations of the 
slats and, indeed, at all intermediate positions. 
The construction is highly advantageous in that the weight of the slats 
tends to urge the free edges of the slats nearest the panes laterally 
outward toward the panes, whereby the possibility of the formation of any 
significant gaps between the slates and the panes is eliminated. By 
minimizing clearances between the edges of the slats and the panes, the 
formation of convective currents, with attendant heat loss, is avoided. 
As will be evident to those skilled in the art and familiarized with the 
instant disclosure, numerous variations may be made in details of 
construction of the invention hereof without departing from the spirit of 
the invention. Accordingly, the invention is to be broadly construed 
within the scope of the appended claims.