Note: Descriptions are shown in the official language in which they were submitted.
BLIND WITH LIGHT-TRANSMITTING SLATS
AND A MUTED FOR MAKING SUCH SLATS
TEC13NICAL FIELD
The present invention relates to blinds in general
and, in particular, to blinds having rotatable,
liyht-transmitting slats.
BACKGROUND OF ART
The at is generally cognizant of blinds having slats
adapted to transmit at least some of the light that
lo in1pinges on them. Malone, U.S. Patent No. 3,645,317 shows
a conventional Venetian blink in which the slats are
covered with a thin layer of metal to reflect unwanted
infer red radiation and yet remain generally transparent
to visible light. In the closed pOSitiOII, the slats of
Malone overlap, doubling the liyilt-blockiny effect of the
blind.
The art is Allah cognizant of blinds that have a
selected color on one face and a second color on the other
face. An example is Squealer, U.S. Patent No. 4t336,834.
The use of blind slats bent along their longitudinal
axis so as to acquire a crows sectional configuration
similar to an inverted V is also known. examples include
Burled, et at., U.S. Patent No. 4,091,592, Trenton, U.S.
. O " , Jo ,
25323
Patent No. 2,318,525, and Ehrenfeld, U.S. Patent No. 2,315,605. Thompson et
at. U.S. Patent No. 3,217,631, shows a similar configuration employed as a
fixed louver. In each case, the bent slat is opaque sod is adapted not to be
turned about its longitudinal axis. The purpose of the bent configuration of
the slats is to block light or provide privacy while allowing a substantial
flow of air.
BRIEF SUMMARY OF THE INVENTION
The present invention is summarized in that a blind having an interior
aide and an exterior side includes a plurality of elongated slats made of a
flexible and generally resilient material having selected light-transmitting
qualities. Each slat is cold formed to provide a transverse cross sectional
configuration in which a first longitudinally extending portion and a second
longitudinally extending portion of the slat intersect to form a selected
angle of 90~ to 160. Means are provided for suspending the slats in parallel
relation, the suspension means being adapted to rotate the slats about their
longitudinal axes between an inwardly facing position, in which the upper
surfaces of the slats are presented at the interior side of the blind with the
first portions of the slats lying substantially within a single plane, and an
outwardly facing position, in which the upper surfaces are presented at the
exterior side of the blind and the second portions of the slats lie generally
within a single plane. The suspension means is further adapted to hold the
slats at a distance from each other such that when the slats are in one of the
inwardly facing and outwardly facing positions the portions of the slats not
then co-planar extend sufficiently fax toward the slat immediately adjacent
thereto as to overlap the immediately adjacent slat, to prevent the passage of
light in a direction generally normal to the co-planar portions of the slats
without that light being interrupted by the slats.
- 2 -
53~
A primary object of the invention is to provide for a blind structure that
is adapted to substantially cover an opening to reduce the glare and light
entering through the opening but to achieve this end without blocking all of
top light that passes there through.
The predominant visual effect of the slats of the blind it that thy
present a substantially planar surface to the viewer while still allowing for
air passage there through.
The blind is capable of being selectively turned to a first position, in
which the blind has a first light-transmltting quality, and a second position,
in which the blind has a second and different light-transmitting quality.
With the blind of this invention the slats are divided into longitudinally
extending portions of differing light transmitting abilities or colors, and
the slats are adapted to exhibit predominantly one or the other
light-transmitting quality or color to an observer of the blind.
The blind and slats also preferably exhibits self-extinguishing burning
characteristics.
The method for making blinds having the qualities referred to above also
produces blind slats are strong but nevertheless light and thin enough to be
conveniently drawn up to the top of the blind, with a minimum of effort, into
a slender stack of slats.
Other objects of the invention will be apparent from the following
detailed description taken on conjunction with the accompanying drawings
showing a preferred embodiment of a blind exemplifying the principles of the
invention.
23
BRIEF DESCRIPTION OF TIE DRAWINGS
Fly. 1 is an isometric perspective view of a blind for
a window made in accord with the principles of the
invention.
Fly. 2 is a perspective view of broken away portions
of several of the adjacent slats of the blind of Fig. 1.
Fig. 3 is a perspective view of the slats of Fig. 2 in
a closed position.
Fly. 4 is a perspective view of the slats of Fly. 2 in
an alternative closed position.
Fly. 5 is a schematic representation of a
manufacturing aLran~ement for the blind of the invention.
ivy. 6 is a schematic side elevation view of a pair of
forming rollers.
jig. 7 is a perspective view corresponding to that of
Fig. 4 showing an alternative embodiment of the slats of
the invention, with several slats broken away.
DETAILED DESCRIPTION E; TIRE PREFERRED EMBODIMENT
Referring lore particularly to the drawings, wherein
like numbers refer to like warts, Fly. 1 shows a blind
generally indicated at 10, made in accord with the resent
invention The blind 10 shown is especially adapted to be
used to cover a window, but the blind of the invention may
ye used to cover other openings or to provide a screen
independent of an openincJ. For convenience of reference,
the blind 10 is deterrlined to have an interior side 11 and
exterior side 13. A head rail 12 extends across the top
of the blind 10 and is adapted to be mounted
horizontally. The head rail 12 includes a tilt rod (not
shown) extending lengthwise therein all adapted to turn
about its longitudinal axis. Ladders 14 made of string or
other flexible materials extend downwardly from the head
rail 12. Each ladder ills parallel side strands 16
connected by spaced runts 18, shown in phantom in Fig. 1.
The side strands are wound on the tilt roll, so that, as
tile tilt rod is rotated about its longitudinal axis one
--5--
way or the other, each side strand 16 of each ladder 14 is
alternately raised or lowered. Preferably a wand 20 is
provided that is attached to the tilt rod by a
conventional mechanical linkage (not shown) such that when
the wan is turned about its longitudinal axis, the tilt
rod turns in a correspolldiny fashion.
The blink I has elongated slats 22 that, in the
embodiment shown in Fly. 1, extend the width of the blind
and are Cypriot by rungs 18 of at least two ladders 14
or by comparable means for support. In the embodiment of
the irlventioll Shelley in Fig. 7, the rungs 18 are omitted,
and adhesive tabs 23 are employed as an alternative means
for support. The tabs 23 are flexibly attached to the
side strands 16, effectively moving in hinged relation
thereto. The tabs 23 are securely adhered to the slats
22, to support them on the side strands 16. Other
conventional support means are familiar to one skilled in
the art and fall within the scope and spirit of the
invention.
As the side strands 16 of the ladders 14 are moved as
a consequence of tile rotation of the tilt rod, each slat
22 may be coated about its longitudinal axis in concert
with the other slats. Each slat has an upper surface 24
and all under surface 26. The slats 22 may be held in a
neutral position, shown in Fix. 2, in which the upper
surface 24 is presented toward the head rail 12. From
tins neutral position, the slats may be rotated to an
inwardly facing position, shown in Fly. 3, in which the
upper surface 24 is presented at the interior side 11 of
the blind 10, and to an outwardly facing position, shown
in Fly. 4, in which the upper surface 24 is presented at
the exterior side 13 of the blind.
'Lowe ladders 14, with their side strands 16 and rungs
I (ox equivalent support means such as the adhesive tabs
23) constitute means for suspension of the slats 22
adapted to selectively rotate the slats about their
longitudinal axe. Clearly alternative suspension means
are possible. Slats 22 could be supported from their ends
and rotated by ally of Many meals known in the auto The
;
ISLE
--6--
susperlsion means Shelley is adapted to support the slats 22
in a generally horizolltal orientation. However,
conventional suspension means are known whereby the slats
22 could be held so as to extend cJenerally vertically.
All such alternative embodiments are within) the scope and
spirit of the invention.
In the embodiment shown in Fix. 1, a sill rail 28 is
located beneath the slat 22 most emote from the head rail
12. 'rho side strands 16 of the wadders 14 are fastened to
the sill rail, which rotates along its longitudinal axis
as the slats 22 are rotated. Each slat 22 has cord slots
30 extending between the upper and under surface 24, 26
thereof. Each slat 22 has at least two cord slots 30,
each slot preferably located at a point at which the slat
is supported by the support means of a ladder 14. Lift
cords 32 extend from the sill rail 2B upwardly through
each set of corresuos~ding cord slots 30 of the slats 22.
The lift cords 32 extend to the head rail 12 and are
routed over pulleys or comparable mechanisms (not shown)
to a convenient side location. Preferably a cord lock
(not shown) it fastened to the head rail 12, and the lift
cords 32 are routed there through. The cord lock is
adapted to selectively lock and release the lift cords 32,
so that a user of the blind may pull the lift cords 32,
moving the sill rail I and the slats 22 to a raised
position, and then lock the lift cords 32 by means of the
cord lock to cause that raised position to be maintained.
The roared embodilslellt of toe slat 22 of the
invention has a V-shaped transverse cross sectional
configuration, as is apparent in Figs. 2, 3, and 4.
Preferably the V-shape opens generally downwardly, but a
yenerall~ upwardly opening orientation is also possible,
as are sideways opelliny orientations in the event that the
slats are held vertically by an alternative suspension
means, as is discussed above. All such alternative
embodiments are within the scope and spirit of the
invention. Each slat has a first portion 34 and second
portion 36 corresponding to the two sides of the V. the
first and second portions 34, 36 intersect (at the apex of
~2S323
--7--
tile V) at an angle A. The angle A is selected to be
generally between 90 and 160, with all of the slats
22 within a single blind 10 exhi~itiny the same angle A.
The first and second portions 34, 3G form the interior and
exterior portion respectively of the slat 22 when it is in
the neutral position. The first and second portions 34,
36 terminate in first and second edges 38, 40 that extend
parallel to the longitudinal axis of the slat 22.
When the slats 22 of the blind 10 are in the inwardly
facirlg position, the first portion 34 of each of the slats
I lies substantially within a single vertical plalle, as
can be appreciated by reference to Fig. 3. Similarly,
when the slats 22 are in the outwardly facillg position,
the second portion 36 Ivies generally within a single
vertical plalle, as is illustrated in ivy 4. Preferably
the distance between the support means of the ladders 14
is selected to be SUCtl that when the slats 22 are in the
inwardly facing position, the second portion 36 of each
slat extends sufficiently aye toward the slat 22
iml;lediately adjacent thereto to overlap the first portion
34 of the adjacent slat 22. Similarly when the slats 22
are in the outwardly facing position, the first portion 34
of each slat extends sufficiently far toward the slat I
immediately adjacent thereto to overlap the second portion
36 of the adjacellt slat. Thus, when the slats 22 are in
either the inwardly or outwardly facing position, light
cannot sass through the blind 10 in a direction generally
normal to the common plane in which either the first or
second portions 34, 36 of the slats 22 lie without
impinging on the slats.
The basic V cross sectional slat shape disclosed has
various advantages, includillg those disclosed herein.
Ilowever~ it will be apparent to one swilled in the art
that two such V shaves may be combined to create related
shapes. For example, two V-shaped slats joined at an eye
I 40 of each (off expressed alternatively, having a
portion 34, I in common) with both V's opening generally
in the same direction form a flat-bottomed channel. Two
V's similarly joined but opening in generally opposite
;;3~3
directions form a Z-sllaped cross sectional shape.
Similarly, the first and second portions of Roth single
and corllbined V's may differ in length, all within the
scope and spirit of the invention.
The slots 22 are made of a material having selected
light transmitting qualities. Preferably at least one of
the first and second portions 34, 36 is transparent so
that a user of the blilld 10 may see out through the
transparent portions with minimal obstruction. If the
first portions 34 are transparent and the slats 22 are in
the inwardly facing position with the first portions
substantially within d single plane, a minimum of
distortion of the view seen through the blind 10 will
occur. In the event the second portion 36 is transparent,
the same analysis holds when the slats 22 are in the
outwardly facing position. The transparent material from
which the slats 22 Jay be made may be colored to screen
out glare or provide an anesthetically pleasing tint when
viewed from either the interior or exterior sides 11, 13.
I've transparent material may be blackened to a desired
shade. Likewise, a transparent material Inlay be selected
that is opaque to ultra violet fight or any selected range
of light wavelengths. Alternatively, the slats 22 may be
made of a material that both transmits and diffuses
visible light, a quality that hereinafter will be referred
to as n translucency
In one referred embodiment of the invention, the
first and second portions 34, I of the slats 22 are made
of the same material and have the same light-transmitting
qualities. Louvre, in an alternative embodiment, the
liyht-transmitting abilities of the first and second
portions differ. Thus, one portion may be transparent and
have a selected color. Roy remaining portion may be
transparent and of a different color, translucency,
opaqueness, reflectiveness, or the like. It will be
appreciated that in either the inwardly facing or
outwardly facing pOSitiOllS, whichever portions 34, 36 of
the slats 22 are substantially co-planar will be
responsible for the predominating effect on light passing
-I q~3
through the blind 10 in a direction generally normal to the plane. Thus,
slats 22 in which the first and second portions 34, 36 hstve different colors
may be changed from the inwardly facing to the outwardly facing position with
the effect of changing the perceived color of the blind 10. One of the first
and second portions 34, 36 may be made darker than the other, allowing the
selection of the degree to which the glare of a bright day can be eliminated.
If the ankle A is made approximately equal to 90, as is shown in Fig. 7, and
if one of the first and second portions 34, 36 is made of a material that is
translucent, opaque, or reflective, that portion can be moved to the co-planar
position and completely obstruct the view through the blind, providing
privacy, darkness, the reflection of radiant energy, or comparable effects,
depend on the nature of the material used. The other portion may be
transparent, for example, providing in a single blind 10 the option of
subjecting substantially all of the light entering through the blind to two
entirely different light modifying treatments.
The slats 22 of the invention may be made of any suitable, sufficiently
rigid material. It is preferred that the slats be made of plastic,
polycarbonate plastics being preferred. The term "polycarbonate" as used
herein includes alloys of polycarbonate. Polycarbonate plastics alloyed with
ABS plastics are known in the art and likewise art well suited to many
embodiments of the invention disclosed herein. A wide variety of
light transmitting qualities may be imparted to such plastics, by mixing
coloring material in with the plastic when it is formulated, coating plastic
stock material on either one or all sides, laminating, and the live. Such
plastics may by immersed in or sprayed with materials that chemically bond
with the plastic, may be painted or otherwise treated with materials that
simply adhere to the surface of the underlying plastic, or may be subjected to
a mechanical surface treatment selected to render a transparent plastic
translucent as, for example, by roughening the surface. Selected parts of a
slat 22 may by subject to such treatments independent of the rest of the slat.
_ g _
to
5323
-10-
Polycarbollate plastics are preferred also because they
have important fire-resisting qualities. Such plastics
are available that, in thicknesses of 0.062 inches,
achieve an SE-l ("self-extinguishiny--l") rating under the
Underwriters Lab flammability Test Bulletin 94~ and an SE
("self-extinyuishing~) rating under the ASTIR D635-68
flammability test. Bromine-modified forms of the plastic
are available that, whelp subjected to the same tests and
in the same thicknesses, attain an SE-O Underwriters Lab
rating and an Lowe ("l30n-burning") ASTM D635-68 rating. The
~olycarbonate plastics sold by the General Electric
Comply under the trademark ALEX AN" are examples of such
plastics. Favorable flammability characteristics are very
important when many slats 22 are used even in a sibyl
blink 10. Control of fire hazards is even more important
when many blinds 10 are located within a riven area or
Building .
In the method for making slats 22 of the invention, a
strip 42 of planar, plastic stock material of a selected
width is prepared. commonly plastic is manufactured in
rolls of considerable width, in which case strips 42 may
be prepared having a width substantially that of the slat
22 to be manufactured my sawincJ, shearillg, or the like
Preferably, the strip 42 of planar, plastic stock material
so wrapper is of indefinite length and is of sufficient
flexibility that the strip may be stored as a reel 44 for
convenient Heinlein.
he strip 42 is then cold-formed to impart to it the V
shape disclosed above. "Cold-formillg~ is the process of
Shannon the shape of a stock material by mechanical
manipulation without the application of heat sufficient to
renter the stock material plastic. Preferably, the strip
42 is directed lengthwise between male and female forming
rolls 4G, 48. The focminy rolls 46, I are generally
circular and are adapted to rotate about their central
axes.
The male Eorlniny roll I has an annular male forming
merger 50 that terminates in a V-shaped male forming
surface 52. The apex of the male forming surface 52 has a
radius selected to impart a generally V-shaped transverse
cross sectional configuration to the strip 42 in which
first and second portions of the strip (destined to become
the first and second portions 34, 36 of the slat 22 being
formed) correspond to the two sides of the V, intersecting
at the apex of the V at the selected ankle A of 90 to
160 desired in the finished slat 22.
The furl forming roll 48 has two, annular female
forming members 54 separated by a selected distance.
Preferably the female forming members 54 terminate in a
generally rounded female forming surfaces 56, although the
female forming surface may also be flat, or even present
an eye toward the male forming roll 46, all within the
scope and Spoil it of the invention. The axes of the male
an female forming rolls 4G, 43 are oriented parallel to
each outlawry with the male forming surface 52 extending
between the female forming surfaces 56. As a strip 42 is
directed between the male and female forming rolls, 46,
48, the male forming surface 52 deflects the strip into a
V shape of the sort exhibited by the slats 22~ as
disclosed above. The male forming roll 46 is so located
relative to the female forming roll 48 that as the male
forming surface 52 is inserted further and further between
the female forming surfaces 56, the ankle A imparted to
the strip 42, corresponding to the ankle A as defined
relative to slats 22, is made smaller and smaller
alternative means for cold-forminy the strip 42 are
possible. For example, either one or both of the
generally circular forming rolls 46, I disclosed above
may be replaced by endless Betsy. Such bullets may be held
tautly by pulleys or be otherwise supported in an
orientation relative to each other analogous to that
disclosed for the circular forming rules 46, 48. One belt
ran present outwardly a male forming surface analogous to
that discussed above. The male forming surface may ye
inserted between two parallel belts, each presenting one
female forming surface toward the male forming surface.
It will be apparent that circular forming rolls and such
endless belts may be used together, as well. For example,
issue
12-
one or more male forming rolls 46, having the structure
disclosed above, may be used with a pair of endless belts
each presenting a female forming surface toward the male
forming roll, one on either side thereof. The use of such
systems as well as the use of breaks and other
cold-forming machinery known in the art, is well within
the scope and spirit of the invention.
Many plastics exhibit a pronounced resilience,
requiring that they be considerably deformed before the
elastic limit of the plastic is exceeded and a permanently
remaining shape may be successfully impacted to the
plastic in a cold-forming process. As a consequence,
gradual curves are difficult to impart to certain plastics
by a cold-Eorming process. The plastic can be deformed
lo into those curves while held between the forming members,
but, if the curve is within the elastic limit of the
plastic, when the forming members are withdrawn, the
plastic returns to its original shape. Thus, the radius
of the apex of the male forming surface 52 must be chosen
to be such that the deformation of the plastic strip 42
over that radius is sufficient to exceed the elastic limit
of the strip
When a flat piece of material having a given thickness
is bent, the part to the outside of the bend experiences
the greatest strain. Thus, the elastic limit in the piece
of material is exceeded first in that part, to result in a
permanent change of shape. As the material is selected to
be increasingly thick, the elastic limit is exceeded with
wends of increasingly large radii. When polycarbonate
plastics are used to make slats 22, it has been found
desirable to restrict the thickness of the slats to 1/16
inch or less. This is done to minimize weight, bulkiness,
and expense, 1/16 inch polycaKbonate plastic can be
cold-formed will a male forming surface 52 having an apex
with a radius of 1/4 inch or less. The preferred slat
thickness when the slats 22 are made of polycarbonate
plastic is from 0.0l5 to 0.030 inches, in which case it
has been found desirable to reduce the radius nearly to 0
and in any event to not more than 1/8 inch. Polycarbonate
~2~5~23
slats 22 of this thickness are lightweight and easily
manipulated. Because of the V-shaped cross sectional
configuration disclosed above, the slats 22 are desirably
stiff and do not sag between the supporting means or at
the ends of tube slats, even when the thickness is less
than 0.015 inches. Nevertheless, the polycarbonate
material is sufficiently flexible and resilient to
withstand a great deal of the bending and flexing
incidental to the normal use of a blind.
It Many plastics exhibit memory," the tendency to return
to or toward an undeformed state after deformation.
Consequently, it is sometimes necessary to impart an
initial deformation to the strip 42 that exceeds that
eventually desired. Then, after the strip 42 has
exhibited such memory as it has been determined by
experiment to have, tile final deforl,lation will be the
desired one. The degree of deformation can be controlled
by so locating the male and female forming rolls 46, 4
relative to each other that the male forming surface 52
extends increasingly between the female forming members
54. Depending on the plastic used to make the strip 42,
it may be desirable to direct the strip between a series
of male and female forming rolls 46, 48, as is illustrated
schematically in Fig. 5, each pair of rolls increasingly
deforming the strip to achieve a final. degree of
Reformation.
The preferred plastic from which to prepare the strip
42 is yolycarbonate plastic material of tile sort discussed
above. SUctl plastics may be conveniently coated with an
acrylic plastic material to impart. desired
liyht-translnittin~ qualities to the strip 42. The
polycarbonate plastic is immersed in a solvent containing
the acrylic plastic, which is deposited Oil the surface of
the strip 42. Acrylic plastics are generally more brittle
than polycarbollate plastics and cannot be conveniently
cold-for-r,le~, especially when considerable deformation is
required. Consequently, when an acrylic-coated
~olycarbonate plastic strip 42 is prepared, it is
desirable to float the strip to a temperature of at least
-14-
125F but not more than 200F before subjecting the
strip to cold-forminy. This is especially desirable when
an acrylic coating is applied to both surfaces of the
strip 42. The acrylic-coated strip 42 should not be
S elevated in temperature to the point that the rigidity of
the polycarbonate plastic is substantially changed.
However, by heating the strip within the temperature range
indicated, the acrylic plastic coating is rendered
thermoplastic and capable of moving with the polycarbonate
plastic strip through the cold-forming process without
separating therefrom or otherwise being rendered
unsatisfactory. The result is a conformed plastic strip
I having a surface coated with acrylic plastic exhibiting
a hardness and optical qualities unobtainable in uncoated
I polycarbonate plastic.
Either before or after the strip 42 has been deformed
by the male and female formillg rolls 46, 48, is is
directed to conventional punches adapted to cut potions
of the strip to desired slat lengths and to create cord
slots 30. Such punches are shown schematically in Fig. 5,
where first punch 58 is adapted to create cord slots 30.
The strip 42 is then advanced through a second punch 60
until the desired slat length extends beyond the second
punch. The second punch 60 is adapted to cut off the slat
22, imparting a desirably curved contour both to the end
of the slat 22 so separated from the strip 42 and to the
now leading end of the strip 42 remaining. By this means,
a single punch 60 in one step imparts the desired shape to
the trailing end of first slat 22 and the leading end of
the next slat 22. The slats 22 so formed may be fed into
the ladders 14 and suspended upon rungs 18 or other
support means, as disclosed above, by conventional
automatic machinery.
It will be appreciated that the method of manufacture
disclosed above has many advantages. The method provides
for a continuous feed of stock material and a continuous
production of slats 22. As opposed to a molding process,
the cold-forming process is fast and efficiently requires
no molding time or the procurement of sophisticated
: '.
;23
-15-
molds. The male and female forming rolls 46, 48 may be
adjustable so that a single forming operation may be
adapted to manufacture swats 22 exhibiting a variety of
angles A. Furthermore, since the process is one of
cold forming the movement of the strip 42 may be
interrupted or periodic if that is desirable to aid the
fullctioning of the punches or other aspects of the
machinery. Upon being stopped in its movement through the
cold-forming machinery, no portion of the strip 42 remains
lo between heated rollers that might cause it to be unevenly
deformed.
It is understood that the present invention is not
limited to the particular construction and arrangement of
parts illustrated and disclosed, nor to the particular
materials disclosed, nor to the particular steps disclosed
herein. Instead, it embraces all such modified forms
thereof as come within the scope of the following claims.
