Note: Descriptions are shown in the official language in which they were submitted.
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ACTUATOR DEVICE AND METHOD FOR MANUFACTURTNG A VIEW
THROUGH WINDOW COVERING
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention generally relates to window coverings and
treatments.
More specifically, the present invention relates to an actuator device
suitable for use with
an adjustable view-through cellular shade or window covering, the cells of a
mufti-cell
window covering and a method for manufacturing the cells of a mufti-cell
window
covering.
Description of the Related Art
[0002] Partly in response to the limitations inherent in traditional window
coverings
like venetian blinds, fresh window coverings and treatments, such as mufti-
cellular shades,
were developed and welcomed by consumers. In the broad sense, a cellular shade
is a
pleated window covering having a plurality of cells arranged adjacent to one
another. The
adjacent cells are bonded at their edges to form a complete sheet for the
window covering.
These mufti-cellular shades provide significant insulating value, uniform
light diffusion
and a desirable aesthetic presentation, but they typically have no view-
through capability.
Unlike traditional venetian blinds, which provide easy modulatable view-
through and light
control by simply adjusting the orientation of the horizontally disposed slats
or vanes,
traditional mufti-cellular shades are not capable of separating the plurality
of cells, thus
preventing a view-through option. Therefore, in order for a person to see
through a
window that is outfitted with a traditional mufti-cellular shade, it is
necessary to
collectively raise and gather the plurality of cells, i.e., raise the entire
window covering.
However, raising the whole cellular window shade is laborious and time
consuming.
(0003] ~ In light of the advantages of venetian blind and mufti-cellular
window shades, a
hybrid window covering was developed that provides the characteristics of both
a venetian
blind and a mufti-cellular window covering. This hybrid window covering
includes a
plurality of cells arranged parallel to one another. Each cell has at least
one side, and a
joint unites adjacent sides of each cell. The adjacent sides are pivotable
about the joint
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such that each cell is variably adjustable between a collapsed position and an
expanded
position. By collapsing and expanding the cells, the window covering can
achieve
adjustable light-control, modulatable view-through, light diffusion, and
excellent insulation
value, all in an aesthetically pleasing design.
[0004] Included in this hybrid window covering is a means for variably
adjusting the
cells between the collapsed position, where adjacent cells are separated, and
the expanded
positioned, where adjacent cells contact one another. The adjustment means
typically
includes a pair of cords that engage and actuate the cells between the
collapsed and
expanded positions. Due to the structure of the cells, the relative position
of the cords in
each pair is not fore-and-aft (i.e., perpendicular to the plane of the window
covering), as in
a conventional venetian blind, but rather is parallel to the plane of the
window covering for
central, balanced lifting and lowering of the upper and lower portions of each
cell. A series
of beads or other suitable attachment elements are secured to the cords and
are engaged
with one or more surfaces of the cells during manufacture.
[0005] One limitation to positioning the cords along a common plane with the
width of
the cells is that the cords generally do not function properly with
conventional head-rail
mounted adjustment mechanisms. More specifically, twisting the cords from the
fore-and-
aft spacing in a conventional head-rail to a position substantially parallel
with the window
covering plane creates an uneven motion between the cords during adjustment.
This
uneven motion causes the cells' weight to be lifted or dropped during
adjustment of the
cells. Thus, the cells tend to jump away from the adjustment mechanism as the
cells
collapse and strongly resist or load the adjustment mechanism as the cells
expand.
[0006] Figure 1 of the drawings illustrates an exemplary window treatment
employing
the cell and cord arrangement described above. Note that in location "A," the
upper
surface of the cell includes a relatively small bead-engaging aperture aligned
vertically
with a larger cord clearance aperture on the lower surface of the cell.
Alternatively, at
location "B," the relatively small bead-engaging aperture is located on the
lower surface of
the cell and the larger cord-clearance aperture is located on the upper
surface of the cell.
Manufacturing alternating apertures on the upper and lower surfaces of a pre-
manufactured, multi-surface cell is generally impractical, as it would require
a separate
manufacturing operation on the upper and lower surfaces of the cell. The
difference in
aperture size alone, regardless of the orientation between dissimilar
apertures, renders their
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formation difficult with conventional punch tooling. In such a manufacturing
operation,
custom tooling is required to malce a two-stage cut in the cell. Additionally,
the scrap
material from the punched upper aperture is likely to be retained in the cell,
having no
sufficiently sized hole in the lower surface of the cell to drop through.
SUMMARY OF THE INVENTION
[0007] An actuator device is provided for use in a view-through window
covering
having a plurality of cells. The actuator device includes at least one
cooperating pair of
control members including a first control member that supports an upper
portion of each
cell and a second control member that supports a lower portion of each cell.
The
cooperating pair of control members support the cells along a plane parallel
to the plane of
the window covering. Relative movement of the control members modifies the
size of the
space between the cells.
[0008] The actuator device may also include an actuator mechanism selectively
operable to create opposite movement of the first and second control members.
A guide
member may also be provided between the actuator mechanism and the control
members to
transition the control members from being aligned substantially perpendicular
to the
window covering plane to being aligned substantially parallel with the window
covering
plane.
[0009] A cell and method of manufacturing a cell for a multi-cell window
covering is
also disclosed. The method begins with the step of providing a flexible
material defined as
an elongated member having axial and transverse directions. A portion of the
flexible
material is then stiffened to create at least one axially extending flexible
junction. At least
one control engagement formation and at least one control clearance formation
are then
created in axially extending sections of the stiffened flexible material that
will become an
upper portion and a lower portion of the cell. The flexible material is then
folded to create
a closed element and the flexible material is secured to itself to maintain
the shape of the
closed element.
[0010] The method of the present invention enables the manufacture of
expandable and
collapsible cells for a window covering, using common raw materials. The
proposed
method uses relatively inexpensive tooling to produce cells having distinct
features in the
upper and lower surfaces of the cells. The ability to create distinct features
in the top and
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bottom surfaces of the cells enables the use of cords that selectively engage
either the
upper or lower portions of the cells at predetermined locations.
[0011] Various additional aspects of this invention will become apparent to
those
skilled in the art from the following detailed description of the preferred
embodiments,
when read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an exploded perspective view showing an actuator device
according to
the principles of the present invention;
[0013] FIG. 2 is a side view of a window covering employing an actuator device
according to an embodiment of the present invention, wherein a plurality of
cells are
arranged in an open (collapsed) position;
[0014] FIG. 3 is a side view of the window covering of FIG. 2, wherein the
cells are
arranged in a closed (expanded) position;
[0015] FIG. 4 is a cross-sectional view of a cord element and cord for use in
expanding
and collapsing the cells of the window covering of FIGS. 2 and 3;
[0016] FIG. 5 is perspective view showing the cord element of FIG. 4 relative
to an
opening in a cell; ,
[0017] FIG. 6 is a top view of a cradle and guide according to the present
invention;
[0018] FIG. 7 is a side view of a window covering employing another embodiment
of
the actuator device of the present invention, wherein a plurality of cells are
arranged in an
open (collapsed) position;
[0019] FIG. 8 is a side view of the window covering of FIG. 7, wherein the
cells are
arranged in a closed (expanded) position;
[0020] FIG. 9 is a side view of a window covering employing another embodiment
of
the actuator device of the present invention, wherein a plurality of cells are
arranged in an
open (collapsed) position;
[0021] FIG. 10 is a cross-sectional view of a sliding cord element, fixed cord
element
and cord for use in expanding and collapsing the cells of the window covering
of FIG. 9;
[0022] FIG. 11 is a side view of a window covering employing another
embodiment of
the actuator device of the present invention, wherein a plurality of cells are
arranged in a
closed (expanded) position;
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[0023] FIG. 12 is a side view of a window covering employing another
embodiment of
the actuator device of the present invention, wherein a plurality of cells are
arranged in a
closed (expanded) position;
[0024] FIG. 13 is a plan view of a laminate prior to folding the laminate into
a cell;
[0025] FIG. 14 is a side view of the laminate of FIG. 13 after folding the
laminate into
a cell; and
[0026] FIG. 15 is a simplified perspective view of an exemplary manufacturing
line for
manufacturing the cells of FIGS. 13 and 14.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Referring now to the drawings, various embodiments of the present
invention
are described in detail. Referring to FIG. 2, an exemplary window covering 10
is shown
within which an actuator device 12 according to the principles of the present
invention may
be advantageously employed. Window covering 10 may include a plurality of
horizontally
disposed elongated cells 14, all of which are preferably arranged parallel to
one another.
Each cell 14 is adapted to be expanded and collapsed so as to provide variable
light control
and see-through capability for window covering 10. FIG. 3 depicts cells 14 in
the
expanded position, wherein adjacent cells 14 are in contact with one another,
while FIG. 2
depicts cells 14 in a partly collapsed position, wherein adjacent cells 14 are
separated from
one another. The design and configuration of window covering 10 is by way of
example
only and is not intended to limit the scope of the invention as claimed.
Accordingly, the
components of the exemplary window covering 10, more particularly cells 14,
can be
arranged and designed in a wide variety of different configurations.
[0028] In order to achieve the collapsibility and expandability of cells 14,
actuation
device 12 employs at least one cooperating pair of control members that are
engaged with
cells 14 along a plane parallel to the plane of the window covering. In the
embodiment
illustrated in FIGS. 1-3, the control members include a cooperating pair of
cords, i.e., a
first cord 16 and a second cord 18. As illustrated in FIG. 1, it is
contemplated that a
plurality of cord pairs could be disposed along the length of cells 14, the
number of pairs
employed generally depending on the width of window covering 10. At their
upper .
extreme, cords 16 and 18 are secured to an actuator mechanism that is housed
in a head-rail
22. In the embodiment illustrated in FIGS. 1-3, the actuator mechanism is a
rotatable
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member 20 that preferably includes a pair of integrally formed arms 23 to
which cords 16,
18 are attached, but is not intended to be limited thereto. As will be
described in further
detail below, rotatable member 20 can be rotated in a direction that causes
first cord 16 to
move upward and second cord 18 to simultaneously move downward, and vice
versa.
[009] Actuator device 12 may include a plurality of rotatable members 20
corresponding in number to the number of cord pairs positioned along the width
of window
covering 10. Each rotatable member 20 is mounted on an axle 24, which in turn
is
supported by a plurality of cradles 26 that are positioned along the length of
axle 24
proximate each rotatable member 20. As illustrated in FIG. 1, each cradle 26
is preferably
a U-shaped structure defining a pair of spaced apart arms 28 each having a
notch 30 that is
sized to receive axle 24. Once assembled, each rotatable member 20 is disposed
on axle 24
substantially between arms 28. Alternatively, rotatable member 20 may be
provided to
one side (i.e., cantilevered) relative to the two arms 28, or only one arm 28
may be
employed per cradle 26, with the plurality of cradles 26 providing the
required stability of
axle 24.
[0030] Referring still to FIG. 1, each cradle 26 preferably includes a guide
member or
portion 32 that is disposed in an opening in head-rail 22. As will be
described in detail
below, guide portion 32 functions to re-position cords 16 and 18 from the fore-
and-aft
spacing at the connection with rotatable member 20 to a side-by-side spacing
substantially
parallel with the plane of window covering 10.
[0031] It will be appreciated that the means of moving cords 16, 18 is not
limited to
rotatable members 20 and that other actuator mechanisms may be employed in
head-rail
22, such as those described in U.S. Patent No. 3,269,453, U.S. Patent No.
5,778,956 and
GB 1,032,124 (the disclosures of which are incorporated herein in their
entirety). For
example, the actuator mechanism may include a cylindrical drum upon which
cords 16, 18
are collected. In another example, the actuator mechanism may include pair of
push rods
within head-rail 22 to which cords 16, 18 are connected. The push rods are
moveable
along the length of head-rail 22 to move cords 16, 18 in opposing directions.
A
conventional rack-and-pinion arrangement could be provided to regulate
movement of the
push rods and a rotatable wand or control rod could be employed to rotate the
pinion. In
yet another example, rotatable members 20 may be mounted in head-rail 22
parallel with
cells 14 such that no twisting of cords 16, 18 is necessary between cells 14
and rotatable
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member 20. A mufti-axle drive mechanism would be required to drive rotation of
the
rotatable members 20 since, in this embodiment, rotatable members 20 would not
share a
common pivot axis.
[0032] Referring again to FIGS. 2 and 3, in order to adjust the shape of each
cell 14,
first cord 16 is adapted to support the lower portion 14A of each cell 14 and
second cord 18
is adapted to support the upper portion 14B of each cell 14. By raising and
lowering first
cord 16 and second cord 18, each cell 14 can be expanded (see FIG. 3) or
collapsed (see
FIG. 2).
[0033] To support the lower portion 14A of each cell 14, first cord 16
includes a
plurality of beads or cell engaging elements 34 positioned along its length.
Elements 34
are preferably spaced equally apart, such as in a bead chain, and each element
34 is adapted
to abut an outer surface of the lower portion 14A of a corresponding cell 14.
When first
cord 16 is raised, each element 34 presses upwardly against and "lifts" the
lower portion
14A of its associated cell 14. This lifting action results in the collapsing
of each cell 14, as
illustrated in FIG. 2. Collapse of each cell 14 is further facilitated by the
lowering of cord
18 (as described below), which occurs simultaneously with the raising of cord
16 due to the
pivotal movement of rotatable member 20. In the fully expanded condition of
each cell 14
(as shown in FIG. 3), elements 34 drop through an enlarged aperture in the
next lower cell,
so as not to interfere with the desired face-to-face contact between adjacent
cells 14 in the
fully closed or view-blocking condition of cells 14.
[0034] Similarly, second cord 18 includes a plurality of beads or cell
engaging
elements 36 positioned along its length. Each element 36 serves the function
of providing
support to the upper portion 14B of a corresponding cell 14. As illustrated in
FIGS. 4 and
5, elements 36 are preferably formed like small spools having a slot 38 that
is slightly
larger than the wall thickness of a mating cell 14 and is preferably
horizontally annular
about each element 36. The upper and lower outer surfaces 37, 39 of elements
36 are
preferably conical to facilitate entry into an opening 40 in cell 14. The
above-described
structure of element 36 is not intended to be limited thereto, but may include
other
configurations such as clips, knots, loops and the like.
[0035] Referring to FIG. 5, opening 40 includes a first portion 42 that is
large enough
for elements 36 to be inserted into, and a second smaller portion 43 separated
from first
portion 42 by a tapered channel 44. Connecting elements 36 to cells 14 is
accomplished by
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inserting element 36 into first portion 42 of opening 40 and subsequently
sliding element
36 into second portion 43. Although not required, connecting elements 36 with
the upper
portion 14B of each cell 14 at portions 43 advantageously reduces the tendency
of cells 14
to flutter when collapsed or nearly collapsed.
[0036] As illustrated in FIG. 2, each element 36 is used to support each cell
14 from
the upper portion 14B thereof. Therefore, when second cord 18 is raised along
its
longitudinal axis, each engaged element 36 supports each cell 14 from the
upper portion
14B thereof, wherein each cell 14 tends to "hang" from its engaged element 36.
By raising
cord 18, each cell 14 is suspended from its upper portion, while the
simultaneous lowering
of cord 16 and associated elements 34 allows the lower portion to move
downwardly,
resulting in the expansion of cells 14.
[0037] Because the operative plane of cooperating cords 16 and 18 is
substantially
parallel with the plane of window covering 10, the expansion of cells 14 is
effected by the
relative raising of second cord 18 and lowering of first cord 16 without
significant fore-
and-aft rotation or tilting of any cell 14 (as opposed to the case of intended
tilting in
conventional venetian blinds). In achieving the collapsibility and
expandability of cells 14,
it is particularly preferred that the ratio of the stiffness of each cell
juncture to the weight of
each cell 14 be selected so as to facilitate cell expandability and
collapsibility. More
specifically, the stiffness to weight ratio should be such that when the cells
are supported
from the upper portion, the weight of each cell 14 is sufficient to facilitate
the opening of
the cell, and when cells 14 are supported from the lower portion, the
stiffness of each cell
is low enough to facilitate the collapsing of the cell. Accordingly, expansion
of cells 14 is
gravity-driven, requiring that cord 16 regulate the expansion of cells 14, not
force it.
[0038] Referring to FIG. 6, guide portion 32 of cradle 26 preferably includes
a pair of
passages 46, each having a first region 48 large enough to allow passage of
elements 34, 36
and a second region 50 that allows passage of cords 16 and 18, but not
elements 34, 36.
Second regions 50 are aligned in the operative plane of cords 16, 18 so that
cords 16, 18
remain aligned in their operating location. Cords 16 and 18 extend up though
guide
portion 32 and are twisted from a plane substantially parallel with the plane
of window
covering 10 to a relative position substantially perpendicular to the window
covering plane,
wherein cords 16, 18 are attached to rotatable member 20. The attachment of
cords 16, 18
to the ends of rotatable member 20 can be made in any of several known
manners,
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including but not limited to, tying and crimping cords 16, 18 to a pair of
posts 51 on
rotatable member 20.
[0039] The upper and lower surfaces of each cell 14 remain substantially
equidistantly
spaced from the cell's central plane A-A with equal and opposite movement of
cords 16
and 18. However, unequal movement of cords 16, 18 undesirably causes the cells
to lift
and fall as a whole rather than a balanced expansion or collapse of each cell
14. Unequal
movement of cords 16, 18 is typically due to a relatively large change in the
angle of cords
16, 18 relative to guide portion 32 as rotatable member 20 rotates.
[0040] To limit the angular change of cords 16, 18 relative to guide portion
32, the
distance between posts 51 on rotatable member 20 is preferably not less than
about twice
the distance between elements 34 and 36 in a single cell 14 when cells 14 are
collapsed. In
the embodiment of FIG. 2, the suggested distance restricts the rotation angle
of rotatable
member 20 to less than about thirty degrees above and below horizontal for
full actuation
of cells 14 between the expanded and collapsed positions. Additionally, the
axis of
rotatable member 20 should be raised above guide portion 32 not less than
approximately
one-half the distance between posts 51 or approximately the distance between
elements 34
and 36 in a single cell 14 when cells 14 are collapsed. Such a restriction
limits the angular
change of cords 16, 18 relative to guide portion 32 as rotatable member 20
rotates.
[0041] Any conventional means may be employed to rotate axle 24, e.g., a
vertically
rotatable wand or control rod, a slide'stick or an electric motor (none
shown).
Additionally, as desirable in most window covering applications, a means of
raising and
lowering window covering 10 may be employed. One means of raising and lowering
window covering 10 utilizes lift cords, which are separate from cords 16 and
18, to lift a
bottom rail (neither shown) and cells 14 therebetween. The lift cords pass up
through cells
14 and into head-rail 22 where they are wound around a turning guide that
brings the lift
cords into alignment within the head-rail. The lift cords pass through a cord
lock in the
head-rail and are tied together at a pull handle that is selectively operated
to raise the
bottom rail and cells 14.
[0042] Alternatively, the lift cords may be accumulated on and paid-out from
axle 24
by fitting each rotatable member 20 with a slip clutch. In this embodiment,
rotation of axle
24 in either direction initially rotates each rotatable member 20 to its
limit. Thereafter,
continued rotation of axle 24 causes each clutch to slip allowing the lift
cord to be
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accumulated on or paid-out from axle 24 while rotatable member 20 is prevented
from
further rotation. This embodiment allows actuator device 10 and the means for
raising and
lowering window covering 10 to be controlled by a single user interface, such
as a loop
cord, rotatable wand and the like.
[0043] Referring to FIGS. 7 and 8, another embodiment of the present invention
is
shown in detail. In this embodiment, a window covering 110 is disclosed that
is
substantially similar to window covering 10 with at least one exception,
namely, elements
36 are not connected with cells 14. Instead, elements 36 abut the upper
portion of cells 14
from underneath similar to the manner in which elements 34 abut the lower
portion of cells
14. Supporting the upper portion of cell 14 in this manner eliminates the need
to
individually connect elements 36 with cells 14 during manufacture. In another
embodiment of the present invention (not illustrated), elements 34 and 36 are
both
connected to the lower and upper portions of cells 14, respectively, in a
manner
substantially similar to that described above.
[0044] Referring to FIG. 9, another embodiment of the present invention is
shown in
detail. In this embodiment, a window covering 210 is disclosed that is
substantially similar
to window covering 10 with at least one exception, namely, first cord 16
includes two
elements per cell 14 instead of the one element 34 described above. More
specifically, for
each cell 14, first cord 16 includes a fixed element 60 and a sliding element
62. As
illustrated in FIG. 10, sliding element 62, which is substantially similar in
structure to
element 36 described above, includes an interior channel 64 that is slightly
larger in
diameter than the diameter of cord 16. Interior channel 64 allows sliding
element 62 to
slide freely on cord 16, while remaining aligned with the orientation of cord
16.
[0045] Sliding element 62 may be made by separately manufacturing two discrete
halves and attaching the halves together around cord 16. Alternatively,
sliding element 62
may be molded onto cord 16 at the same time fixed elements 60 are molded
around cord
16. In this manner, a thin tubular member (not shown) is temporarily inserted
between
cord 16 and sliding member 62 during the molding operation. The tubular member
is
removed after sliding member 62 is molded around cord 16 to create interior
channel 64.
[0046] Like element 36 described above with respect to cord 18, sliding
element 62 is
connected to its mating cell 14. In contrast, fixed element 60 is affixed to
cord 16 and
supports sliding element 62, which rests on top of fixed element 60 unless
otherwise
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disturbed. In this manner, the lower portion 14A of each cell 14 is indirectly
supported and
laterally guided, but not vertically positioned by fixed element 60 during
closure. While
sliding elements 62 provide no vertical positioning of cells 14, each sliding
element 62
functions to resist tilt and flutter of its mating cell 14. Thus, a third cord
(not illustrated)
may be used to guide sliding elements 62, instead of using cord 16 to guide
both sliding
elements 62 and move fixed elements 60. The upper portion 14B of each cell 14
preferably remains fully engaged with element 36, to provide uniform cell
spacing and
flutter resistance.
[0047] Referring to FIG. 11, another embodiment of the present invention is
shown in
detail. In this embodiment, the axis of rotatable member 20 is raised above
guide portion
32 a distance significantly greater than the spacing between elements 34 and
36 in a single
cell 14 when cells 14 are collapsed. In this embodiment, the angle of cords 16
and 18
relative to guide portion 32 is reduced as compared to the embodiment
illustrated in FIGS.
2 and 3, resulting in a smaller angular change in cords 16, 18 relative to
guide portion 32 as
rotatable member 20 rotates.
[0048] Referring to FIG. 12, another embodiment of the present invention is
shown in
detail. In this embodiment, rotatable member 20 includes a pair of arc-shaped
cam
members 52. Cam members 52 arc about the center of rotation of rotatable
member 20 so
that rotation of rotatable member 20 does not substantially change the angle
of cords 16; 18
relative to guide portion 32.
[0049] As illustrated in FIG. 13, a single cell 14, according to an embodiment
of the
present invention, is fabricated from a strip of a flexible material 76, such
as a woven
fabric. In a first manufacturing step, flexible material 76 is stiffened, such
as by applying a
curable stiffening compound to flexible material 76, or by laminating flexible
material 76
with at least one stiffening member 78, such as, for example, a narrow strip
of plastic film,
stiffened fabric or metal ribbon.
[0050] In an exemplary embodiment of the present invention, flexible material
76 is
laminated with at least two stiffening members 78, each spaced a predetermined
distance
apart, to form a laminate 80. Optionally, for aesthetic reasons, at least one
of stiffening
members 78 may be colored prior to laminating flexible material 76. The
colored
stiffening members) 78 is secured to flexible material 76 in an area that will
be visible
from within a room where the window covering is extended. Because the flexible
material
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76 selected may be translucent, the colored stiffening members) is visible
through the
material, permitting cells 14 of the window covering to match the decor of the
room.
[0051] Preferably, for reasons that will be explained below, the stiffening
members that
help form the upper and lower portions of cells 14, depicted as stiffening
members 79 in
FIG. 13, are a substantially rigid, yet formable material, such as metal. The
gaps 82
provided between stiffening members 78, 79 permit flexible material 76 to act
as a living
hinge, allowing laminate 80 to be folded into a multi-sided tubular element
84. A closure
seal 86, such as an adhesive or double sided tape, is provided between
opposing edges 88,
90 of laminate 80 to retain tubular element 84 in tubular form. The joint
between edges 88,
90 may be created as an overlapping joint, as illustrated in FIG. 14 or,
alternatively, a butt-
type joint (not shown).
[0052] In the process of manufacturing tubular element 84, it is desirable to
maximize
the longitudinal bending stiffness of laminate 80 to minimize the number of
pairs of
support cords 16, 18 needed to support cells 14 in window covering 10.
Referring to FIG.
15, to increase the bending stiffness of laminate 80, stiffening members 79
are roll-formed
or otherwise processed by a forming device 89 to give stiffening members 79 a
curved,
transverse cross-sectional shape (not illustrated). Forming the metal
stiffening members 79
in this manner increases their effective section modulus, thereby increasing
the longitudinal
bending stiffness of laminate 80 as a whole. Alternatively, stiffening members
79 may be
formed with a slight curve prior to laminating flexible material 76,
particularly when
stiffening members 79 are made from materials other than metal.
[0053] Prior to closing cell 14, stiffening members 79 are punched with a
series of
openings 40 by a punching tool 91. The spacing between openings 40 is
generally a
function of the bending stiffness of cells 14 and the relative vertical
position of cords 16,
18. Because the portions of laminate 80 that will later become aligned at each
location in
top and bottom arrangement are, at this step, side-by-side transverse to the
length of
laminate 80, the punching operation can be accomplished simultaneously with
one tool for
both top and bottom openings 40. Alternatively, openings 40 may be created in
laminate
80 by slitting, stitching or otherwise forming an engagement feature in
laminate 80 for
receiving elements 34, 36 or allowing passage of cords 16, 18. In addition,
punching of
adjacent openings 40 can also be achieved either simultaneously or in timed
sequence with
multiple punching tools, instead of the single punching tool described above.
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[0054] The punched laminate 80 is then moved over a series of guides 92 that
fold
laminate 80 along at least two predetermined hinge lines, bringing the upper
and lower
surfaces of laminate 80 into an over-and-under position, as shown in FIG. 15.
Closure seal
86 is then adhered to opposite edges of laminate 80, in an overlapping manner,
to form the
closed element 84. The cross-sectional profile of closed element 84 and
finished cells 14
are not limited to the profile shown in FIGS. 2 and 3. It will be appreciated
that the
method of the present invention may be used to manufacture cells having
different cross-
sectional profiles, including, but not limited to, the cells disclosed in U.S.
Patent No.
5,680,891 to Kendall Prince.
[0055] Referring still to FIG. 15, each closed element 84 is then directed
through a
shearing machine 94, which is continuously timed by a measurement of the
position of
laminate 80, so as to be in register with the position of the punched openings
40. The
position of laminate 80 may be continuously determined, for example, by a
conventional
encoder on pulling rolls 96, which act to pull laminate 80 through the
manufacturing line,
or by other means known in the art. This shearing operation generates a
plurality of cells
14 with regularly spaced openings 40, symmetrically located between the
sheared ends of
cells 14. Cells 14 may then be strung together with cords 16 and 18, as
described above,
and attached to the actuator mechanism in head-rail 22 to form window covering
10.
Alternatively, closed element 84 may be sheared into discrete cells before
punching, such
as by using a set of substantially identical punches on a self-spacing
pantograph linkage
(none illustrated), to provide for substantially equal spacing of the punches
between
sheared ends.
[0056] The disclosed method enables the manufacture of expandable and
collapsible
cells for a window covering, using common raw materials. The proposed method
uses
relatively inexpensive and ordinary tooling to produce cells having distinct
features in the
upper and lower surfaces of the cells. The ability to create distinct features
in the top and
bottom surfaces of the cells enables the use of cords that selectively engage
either the
upper or lower portions of the cells at predetermined locations. Such
selective engagement
permits independent, but coordinated, control of the expansion and collapse of
the cells in a
cellular window covering.
[0057] Although certain preferred embodiments of the present invention have
been
described, the invention is not limited to the illustrations described and
shown herein,
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which are deemed to be merely illustrative of the best modes of carrying out
the invention.
A person of ordinary skill in the art will realize that certain modifications
and variations
will come within the teachings of this invention and that such variations and
modifications
are within its spirit and the scope as defined by the claims.
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